WO2003100849A1

WO2003100849A1 - Semiconductor processor

Info

Publication number: WO2003100849A1
Application number: PCT/JP2003/006541
Authority: WO
Inventors: Shinya Nishimoto
Original assignee: Tokyo Electron Limited
Priority date: 2002-05-28
Filing date: 2003-05-26
Publication date: 2003-12-04

Abstract

A semiconductor processor comprises a mount stage (4) having an electrostatic chuck (42) that electrostatically chucks the rear face of a wafer (W) to be processed. When the rear face of the wafer (W) is electrostatically chucked by the electrostatic chuck (42), charge of first polarity develops on this rear face. A separation member (51) is arranged to selectively separate the wafer (W) from the mount stage (4). A charge supply section (6) is arranged to selectively supply charge of second polarity opposite to the first polarity to the rear face of the wafer (W). A control section (8) controls a charge supply section (6) to supply charge of the second polarity to the rear face of the wafer (W) immediately before the separation member (51) separates the wafer (W) from the mount stage (4).

Description

Specification

Semiconductor processing equipment

Technical field

The present invention relates to a semiconductor processing apparatus and a method of detaching a substrate to be processed from an electrostatic chuck in the semiconductor processing apparatus. Here, semiconductor processing refers to forming a semiconductor layer, an insulating layer, a conductive layer, and the like in a predetermined pattern on a substrate to be processed such as a semiconductor wafer or an LCD substrate. It means various processes performed to manufacture a structure including a semiconductor device II, wiring connected to the semiconductor device, electrodes, and the like on a processing substrate.

Background art

2. Description of the Related Art In a semiconductor device manufacturing process, there are many processes in which a substrate is processed in a vacuum atmosphere, such as, for example, film formation by etching or chemical vapor deposition (CVD). In a vacuum processing apparatus that performs such processing, an electrostatic chuck is generally used to fix a substrate to a mounting table on which a substrate to be processed is mounted.Figure 9 shows a conventional vacuum processing apparatus used in a vacuum processing apparatus. FIG. 2 is a longitudinal sectional view showing the mounting table structure of FIG. 1, showing a state where a semiconductor wafer W is mounted on the mounting table 1. The mounting table 1 includes a base 11, an electrostatic chuck 12 disposed on the upper surface thereof, and a ring body 13 surrounding the electrostatic chuck 12. The electrostatic chuck 12 is made of an insulating layer 15 made of a dielectric material, for example, a polyimide, for example, on both sides of a sheet-like chuck electrode 14 having conductivity. It has a sandwiched configuration. When a DC voltage (chuck voltage) is applied from the DC power supply 16 to the chuck electrode 14, a gap between the electrostatic chuck 12 and the wafer W is generated. Then, a Coulomb force is generated, whereby the wafer W can be suction-held on the mounting table 1.

Inside the mounting table 1, support pins 17 (three in the circumferential direction) for detaching the wafer W from the electrostatic chuck 12 are provided so as to be able to protrude and retract. . When the processing on the wafer W is completed and the electrostatic chuck 12 is removed, the connection of the switch SWA is switched to the ground side when the wafer W is detached. As a result, the application of the positive voltage to the chuck electrode 14 is stopped, and the electric charge existing on the surface of the electrostatic chuck 12 is removed to attract the wafer W to the wafer W on the surface. Weaken power. Next, the support pins 17 are raised to detach the wafer W from the surface of the electrostatic chuck 12. At this time, when the switch SWB is closed, a part of the residual charges on the wafer W side is released to the ground via the conductive support pins 17.

When the wafer W is detached from the electrostatic chuck 12 as described above, static elimination of the surface of the electrostatic chuck 12 is performed. However, due to factors such as the warpage of the wafer W and the undulation of the insulating layer 15, a site where the charge is strongly attracted is localized on the surface of the wafer W and the electrostatic chuck 12 (insulating layer 15). As a result, static elimination may not be performed sufficiently. When the wafer W is detached in such a state, the support pins 17 forcibly peel the wafer W from the electrostatic chuck 12. As a result, for example, problems such as one side of the wafer W jumping up and the wafer W falling from the support pin 17 occur. In addition, if the above method is used to ensure static elimination, a long time is required and the throughput is reduced. 1

3 Disclosure of the invention

An object of the present invention is to prevent the occurrence of a detachment abnormality and to reduce the time required for detachment in a semiconductor processing apparatus when detaching a substrate from an electrostatic chuck. And.

A first aspect of the present invention is a semiconductor processing apparatus for performing semiconductor processing on a substrate to be processed having a conductor or a back surface of a semiconductor,

A processing chamber for storing the substrate to be processed,

A mounting table for mounting the substrate to be processed in the processing chamber; and the mounting table having an electrostatic chuck for electrostatically adsorbing the back surface of the substrate to be processed; and the back surface of the substrate to be processed. When the electrostatic chuck is electrostatically attracted by the electrostatic chuck, a charge of the first polarity is generated on the back surface;

A detaching member for selectively detaching the substrate to be processed from the mounting table,

A charge supply unit that selectively supplies a charge of a second polarity opposite to the first polarity to the back surface of the substrate to be processed;

A control unit configured to control the operation of the detachment member and the charge supply unit; and the control unit supplies the charge supply immediately before the detachment of the substrate to be processed from the mounting table by the detachment member. Supplying the charge of the second polarity to the back surface of the substrate to be processed by a unit;

Is provided.

A second aspect of the present invention is a semiconductor processing apparatus for performing semiconductor processing on a substrate to be processed having a conductor or a semiconductor back surface. The method according to claim 1, wherein the substrate to be processed is detached by a detaching member from an electrostatic chuck that electrostatically attracts the back surface of the substrate to be processed on a mounting table. When the back surface of the substrate is electrostatically attracted by the electrostatic chuck, a charge of a first polarity is generated on the back surface.

Stopping the application of voltage to the chuck electrode of the electrostatic chuck;

Next, supplying a charge of a second polarity opposite to the first polarity to the back surface of the substrate to be processed,

Next, a step of detaching the substrate to be processed from the mounting table by the detachment member,

Is provided.

A third aspect of the present invention is a semiconductor processing apparatus for performing semiconductor processing on a substrate to be processed,

A processing chamber for storing the substrate to be processed,

A mounting table for mounting the substrate to be processed in the processing chamber, and the mounting table having an electrostatic chuck for electrostatically adsorbing a back surface of the substrate to be processed;

A vibration supply unit that selectively supplies vibration to the elevating member; a control unit that controls operations of the detachment member and the vibration supply unit; Immediately before the substrate is detached from the substrate, the vibration supply unit may be in contact with the detaching member and the back surface of the substrate to be treated. Supplying the vibration to the substrate to be processed via the detachment member;

Is provided.

According to a fourth aspect of the present invention, in a semiconductor processing apparatus for performing a semiconductor process on a substrate to be processed, the semiconductor substrate is separated from an electrostatic chuck that electrostatically attracts a back surface of the substrate to be processed on a mounting table. A method for detaching the substrate to be processed by a member,

Next, supplying vibration to the substrate to be processed via the detachment member in a state where the detachment member is brought into contact with the back surface of the substrate to be treated;

Is provided.

BRIEF DESCRIPTION OF THE DRAWINGS--FIG. 1 is a longitudinal sectional view showing a semiconductor processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a method of detaching the wafer from the electrostatic chuck in the apparatus shown in FIG.

3A and 3B are enlarged sectional views showing an electrical relationship between a wafer and an electrostatic chuck in the apparatus shown in FIG.

FIG. 4 is a longitudinal sectional view showing a semiconductor processing apparatus according to a second embodiment of the present invention.

Figure 5 shows the wafer and electrostatic chuck in the device shown in Figure 4. FIG. 4 is a schematic plan view showing the positional relationship between and a support pin.

FIG. 6 is a flowchart showing a method of detaching the wafer from the electrostatic chuck in the apparatus shown in FIG.

7A, 7B, and 7C are cross-sectional views illustrating a method of desorbing a wafer W in a process order.

FIG. 8 is an enlarged cross-sectional view showing an electrical relationship between a wafer and an electrostatic chuck in the apparatus shown in FIG.

FIG. 9 is a longitudinal sectional view showing a conventional mounting table structure used in a vacuum processing apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings. In the following description, components having substantially the same functions and configurations are denoted by the same reference numerals, and repeated description will be made only when necessary.

First Embodiment>

FIG. 1 is a longitudinal sectional view showing an etching apparatus (vacuum processing apparatus) as a semiconductor processing apparatus according to a first embodiment of the present invention.

As shown in FIG. 1, this processing apparatus has a processing chamber 2 formed from a vacuum vessel. The vacuum chamber or processing chamber 2 is formed of, for example, aluminum so as to form an airtight structure and is grounded. In the processing room 2, a shower head 3 serving as a grounded upper electrode is provided on the ceiling. A mounting table 4 also serving as a lower electrode is disposed on the floor in the processing chamber 2 so as to face the shower head 3. On the bottom surface of the processing chamber 2, an exhaust port connected to a vacuum exhaust unit 21 composed of, for example, a turbo molecular pump or a dry pump is formed through an exhaust pipe 22 as a vacuum exhaust path. An opening 23 for carrying a substrate to be processed, for example, a wafer W, is formed in a side wall of the processing chamber ² , and can be opened and closed by a gate valve G. For example, ring-shaped permanent magnets 24 and 25 are disposed outside the side wall at positions sandwiching the opening 23 vertically.

A gas supply unit 33 for supplying a processing gas such as a reactive gas or an inert gas is connected to an upper portion of the shower head 3 via a gas supply pipe 32. In the shower head 3, a large number of holes 31 are formed on the mounting table ⁴ at positions facing the wafer W. The processing gas supplied from the gas supply pipe 32 diffuses in the processing gas flow path formed in the shower head 3 and is uniformly supplied to the surface of the wafer W via the hole 31.

The mounting table 4 includes, for example, a cylindrical base 41 made of aluminum. The base 41 is disposed on the floor of the processing chamber 2 in a state of being insulated by the insulating member 41a. A high frequency power supply 40 for applying a high frequency for bias is connected to the base 41 via a capacitor C 1 and a coil L 1. A baffle plate 44 for forming a uniform exhaust flow in the circumferential direction of the wafer W at the time of evacuation is disposed on the side wall of the mounting table 4. The baffle plate 44 is a ring-shaped plate member extending from the mounting table 4 to the vicinity of the inner wall surface of the processing chamber 2.

Wafer W is held almost horizontally on the upper surface of base 41 An electrostatic chuck 42 is provided to perform the operation. A conductive ring 43, which is a ring-shaped conductive member, is provided so as to surround the periphery of the electrostatic chuck 42. The conductive ring 43 plays a role of diffusing the dense plasma on the periphery of the wafer W and in the vicinity thereof, and improving the uniformity of the plasma. An insulating ring 43a, which is a ring-shaped insulating member, is provided between the conductive ring 43 and the base 41.

The electrostatic chuck 42 is made of a conductive sheet-like chuck electrode 46 which is made of a dielectric material such as polyimide, aluminum, aluminum nitride, or the like. It has a configuration sandwiched between insulating layers 45. The chuck electrode 46 is selectively connected to a DC power supply 47 and a ground via a switch SW1. The distance between the surface of the insulating layer 45 and the chuck electrode 46 is, for example, about 0.25 mm. When a DC voltage (chuck voltage) is applied from the DC power supply 47 to the chuck electrode 46, a Coulomb force is generated between the electrostatic chuck 42 and the wafer W, which causes Thus, the wafer W can be suction-held on the mounting table 4. When releasing the suction of the wafer W, the switch SW1 is switched to release the electric charge near the electrostatic chuck 42 to the ground.

A residual charge monitor 7, which is a residual charge monitoring means, is connected in the middle of a circuit connecting the chuck electrode 46 and the DC power supply 47. The control unit 8 via the residual charge monitor 7 can grasp the progress of the electrostatic chuck 42 in the following manner when static elimination is performed. That is, for example, the charge amount Q 1 flowing when the switch SW 1 is connected to the DC power supply 47 is stored. Next, connect switch SW1. Measure the amount of charge Q 2 flowing when switching to the ground side. Then, the charge amount Q 2 is subtracted from the charge amount Q 1 (Q 1 −Q 2), and the charge remaining in the electrostatic chuck 42 is obtained.

In order to transfer the wafer W to and from an external transfer arm (not shown) inside the mounting table 4, a plurality of support pins 51, which are detachable members, for example, elevating members, are provided. It is arranged to be freely retractable. The support pin 51 is moved up and down by a drive mechanism 53 via a connecting member 52. A bellows 54 is provided to maintain the airtightness between the through hole in which the support pins 51 are provided and the atmosphere side. For the support pin 51, the connecting member 52, and the drive mechanism 53, for example, a material selected from a conductor such as aluminum or stainless steel is used.

A charge supply unit 6 for supplying a positive charge to the wafer W via the support pin 51 is connected to the connecting member 52. The polarity of the charge supplied by the charge supply unit 6 is set so as to be opposite to the charge generated on the back surface of the wafer W when the back surface of the wafer W is electrostatically attracted by the electrostatic chuck 42. Is done. That is, when a negative charge is generated on the back surface of the wafer W during electrostatic chucking, the charge supply unit 6 is set to supply a positive charge, and the positive charge is set on the back surface of the wafer W during electrostatic chucking. Is generated, the charge supply unit 6 is set to supply a negative charge. The charge supply section 6 includes a resistor 61 and a DC power supply 62, and the support pin 51 is selected between the DC power supply 62 and the ground section by switching the switch SW2. Connected. The operation of the drive mechanism 53 and the switching of the switches SW 1 and SW 2 are controlled by the control unit 8. Next, the operation of the processing apparatus shown in FIG. 1 performed under the control of the control unit 8 will be described. The gate valve G is opened, and the load chamber (not shown) set to the adjacent vacuum atmosphere and the processing chamber 2 are communicated through the opening 23. Next, a substrate to be processed, in this example, a semiconductor wafer (silicon wafer) W, is loaded into the processing chamber 2 from the load lock chamber by a transfer arm (not shown). Next, the wafer W is mounted on the mounting table 4, that is, on the electrostatic chuck 42, by the cooperative operation of the transfer arm and the support pins 51. Next, the switch SW 1 is switched to the DC power supply 47 side to turn on the electrostatic chuck 42, and the wafer W is attracted to the surface of the mounting table 4.

On the other hand, after the transfer arm has been withdrawn from the processing chamber 2, the gate valve G is closed, and the inside of the processing chamber 2 is evacuated via the exhaust pipe 22. Next, a processing gas is supplied to the wafer W from the showerhead 3 while the vacuum is being drawn, and the pressure in the processing chamber 2 is, for example, 3 OmTorr to 100 mTorr (about: Adjust so that it is maintained at ~ 13.3 Pa). Next, a high-frequency voltage is applied between the mounting table 4 serving as the lower electrode and the shower head 3 serving as the upper electrode by the high-frequency power source 40 to convert the processing gas into plasma, and the magnet 24 , 25 to increase the density of the plasma. The plasma generated in this manner is used to etch, for example, a silicon oxide film on the surface of the wafer W. After performing etching for a predetermined time, the high-frequency power supply 40 is stopped. Then, the process proceeds to a step of detaching the wafer W from the electrostatic chuck 42.

FIG. 2 shows a static state of the apparatus shown in FIG. This is a flowchart showing a method for detaching the wafer W from the electric chuck 42.

First, the switch SW1 is switched to the ground side to remove static electricity from the electrostatic chuck 42. Next, the drive mechanism 53 starts to raise the support pin 51 (step S1). Next, for example, the lifting operation of the support pin 51 is stopped at a predetermined lifting amount (step S2). In this case, it is preferable to preliminarily carry out a test to determine the amount of elevating and lowering at which the tip of the support pin 51 is pressed against the wafer W with a certain contact pressure to ensure contact. The timing for stopping the raising operation of the support pin 51 is not limited to this. For example, the support pin 51 can be raised to a predetermined contact pressure by using a pressure sensor. Alternatively, the support pin 51 may be raised for a preset time using a timer.

Next, the switch SW2 is switched to the DC power supply 62 side to start supplying the reverse charge to the wafer W (step S3). That is, since a negative charge is generated on the back surface of the wafer W by supplying a positive charge to the chuck electrode 46, the support pin 51 is used in this embodiment. A positive charge is supplied to the wafer W via the. As a result, the negative charges remaining on the rear surface side of the wafer W are neutralized by the injected positive charges. At this time, the control unit 8 monitors the residual charge by the residual charge monitor 7 and compares the residual charge with a predetermined set value (step S4).

When the residual charge falls below the set value, the support pins 51 are raised again by the drive mechanism 53 so that the wafer W is pushed up. Detach it from the mounting table 4 (step S5). It should be noted that the set value of the residual charge can be a level when the negative charge on the back surface of the wafer W is completely neutralized. Alternatively, the set value can be set to a level at which the charge is removed to the extent that a suction force that does not cause a detachment abnormality even when the wafer W is pushed up by the support pins 51 remains. Alternatively, this set value may be set to a level at which a slight positive charge accumulates on the back surface of the wafer W to generate a small repulsive force with the electrostatic chuck 42 as described later. it can.

3A and 3B are enlarged cross-sectional views showing an electrical relationship between the wafer W and the electrostatic chuck 42 in the apparatus shown in FIG. The mechanism of static elimination when the wafer W is detached in the apparatus shown in FIG. 1 will be described with reference to FIGS. 3A and 3B.

As shown in FIG. 3A, when a positive voltage is applied to the chuck electrode 46, the surface of the insulating layer 45 (the surface of the electrostatic chuck 42) becomes positively charged. Although this mechanism is not completely understood, polarization occurs in the case of an insulator, and in the case where a slight low-resistance element is contained in the insulating layer 45, the chuck electrode 46 is formed. It is considered that the positive charge moves to the surface and becomes positive.

The surface of the electrostatic chuck 42 and the back side of the wafer W both have irregularities as shown in FIG. 3A when viewed microscopically. In the vicinity of the approaching parts P l and P 2 where these two irregularities approach, the charge is

It is considered that the binding force between the negative charge on the wafer side and the positive charge on the electrostatic chuck side is strong, and a large amount of charge is gathered here to generate a strong adsorption force. In this state, the coulomb attracts the positive charge of the electrostatic chuck 42 and the negative charge of the wafer W to each other. 6541

The wafer W is electrostatically attracted to the electrostatic chuck 42 by the action of 13 anchors (attraction).

After the etching of the wafer W is completed, the static electricity of the electrostatic chuck 42 is removed through the grounding portion. However, since the residual charge remains, the electrostatic attraction force is weakened, but the electrical state is the same as that shown in Fig. 3A.

On the other hand, as shown in FIG. 3B, when positive charges are gradually injected from the charge supply unit 6 into the wafer W through the support pins 51, the positive charges are self-contained inside the semiconductor wafer W. Move around for free. The positive charge is attracted to and collected by the negative charge collected at the approach site P1, thereby acting to electrically neutralize the negative charge. Therefore, the negative charge of the wafer W is canceled by the injected positive charge. In addition, the positive charge of the electrostatic chuck 42 having no partner to be escaping escapes from the ground portion connected to the chuck electrode 46 and the residual charge decreases. Therefore, the electrostatic attraction force acting between electrostatic chuck 42 and wafer W is weakened.

According to the present embodiment, by supplying a reverse charge to the semiconductor wafer W, the electrostatic chucking force can be weakened and the wafer W can be detached. That is, since the wafer W is a semiconductor, the electric charge can move freely within the wafer W. For this reason, in the wafer W, negative charges are concentrated at the approach site P 1 during electrostatic attraction, and injected charges flow into a portion where the negative charges are concentrated when reverse charges are injected. Since the amount of neutralization (the amount of negative charge to cancel out) and the amount of injection correspond to each other, it is easy to control the injection of reverse charges, and the 03 06541

14

Appropriate timing for W desorption can be created. As a result, the detachment operation of the wafer W is stabilized, and detachment abnormalities such as the wafer W dropping from the support pins 51 or causing a displacement can be suppressed. In addition, since the amount of neutralization and the amount of injection correspond to each other even with a small current, static elimination is performed smoothly, and therefore, throughput can be improved.

It is also conceivable to inject a reverse charge into the electrostatic chuck 42 to cancel the residual charge. However, in this case, it is not clearly understood what polarization state the inside of the insulating layer 45 has at the time of electrostatic adsorption, and even if a reverse charge is injected, the charge is not transferred to the insulating layer 4. There is no guarantee that you will move within 5 to reach the approaching site P2. In addition to the injected charges, there may be charges coming out of the crystal. Therefore, it is difficult to detach the wafer W without causing the detachment abnormality unless the positive charge of the approaching part P 2 is canceled. For this reason, even if the reverse charge is gradually injected into the electrostatic chuck 42, it does not easily desorb. On the other hand, when the charge supply amount (current) per unit time is increased, negative charge is accumulated on the surface immediately after being electrically neutralized, and the wafer W is adsorbed again. When supplying the reverse charge to the electrostatic chuck 42 in this way, there is a problem that it is difficult to control the supply of the reverse charge.

The method for supplying the reverse charge to the wafer W is not limited to the method described above. For example, reverse charges can be supplied in accordance with the amount of change in the residual charge detected by the residual charge monitor 7 per unit time. That is, for example, when the amount of change is large, the voltage is lowered to supply a reverse charge. When the supply amount is small, or when the change amount is small, the control (feedback control) may be performed by increasing the supply amount of the reverse charge. In this case, even if the amount of residual charge varies in each process, a minute charge corresponding to the residual charge can be supplied. Therefore, the electrostatic attraction force can be weakened in a short time, and the same effect as in the above case can be obtained. Further, for example, the reverse charge may be supplied in a pulse form using a pulse generator.

Alternatively, the supply of the reverse charge may completely cancel the negative charges collected at the approaching part P 1 of the wafer w completely, and then the supply of the reverse charge may be continued. In this case, since the wafer W bears a positive charge, a Coulomb force (repulsive force) repelling between the positive charge of the electrostatic chuck 42 and the positive force of the electrostatic chuck 42 acts, and the pushing force of the support pin 51 is reduced. The wafer W can be detached without any need. If the supply amount of the reverse charge is too large, the repulsive force acts so strongly that the wafer W may deviate from the predetermined mounting position. For this reason, it is preferable to determine the timing (set value of the residual charge) to stop the supply of the reverse charge by performing a preliminary test (switch the switch SW 2 to the ground part). .

Further, in order to supply a reverse charge to the wafer W, a member other than the support pins 51 of the elevating member can be used. For example, a low-resistance charge supply member for charge supply may be separately provided. Even with such a configuration, the same effect as described above can be obtained.

In addition, the supply of the reverse charge is stopped and the operation shifts to the desorption operation. PC Mengxiang 541

16 is not limited to the one by the residual charge monitor 7. For example, a configuration may be adopted in which a timer is provided in the control unit 8 so that the desorption operation starts at a time measured in advance. In addition, the substrate to be processed is not limited to the semiconductor wafer W, and the present embodiment can be applied to other substrates to be processed as long as they have a conductor or a back surface of a semiconductor.

Second Embodiment>

FIG. 4 is a longitudinal sectional view showing an etching apparatus (vacuum processing apparatus) as a semiconductor processing apparatus according to a second embodiment of the present invention.

As shown in FIG. 4, this processing apparatus has a processing chamber 102 formed from a vacuum vessel. The vacuum chamber or processing chamber 102 is formed of, for example, aluminum so as to form an airtight structure and is grounded. The ceiling in the processing chamber 1 0 within 2, head 1 ² 1 is arranged to shower that also serves as a top of the electrode which is grounded. The floor in the processing chamber I 0 within 2, is disposed in head 1 ₂ 1 and the counter to载置table 1 0 3 starve catcher Wa one also serving as a lower electrode.

On the bottom of the processing chamber 102, an exhaust port connected to a vacuum evacuation unit 119 such as a turbo molecular pump or a dry pump via an exhaust pipe 120 as a vacuum evacuation path is provided. It is formed. Openings 122, 123 for loading and unloading a substrate to be processed, for example, a wafer W, are formed in the side wall of the processing chamber 102, which can be opened and closed by a gate valve G. . Outside the side walls, for example, ring-shaped permanent magnets 124 and 125 are arranged at positions vertically sandwiching the openings 122 and 123 respectively. PC sure 541

A gas supply unit 129 for supplying a processing gas such as a reaction gas or an inert gas is connected to an upper portion of the shower head 127 via a gas supply pipe 127. Further, a large number of holes 126 are formed in the shower head 122 at positions facing the wafer W on the mounting table 103. The processing gas supplied from the gas supply pipe 127 is diffused in the processing gas flow path 128 formed in the shower head 121, and the processing gas is supplied to the wafer W through the hole 126. It is uniformly supplied to the surface.

The mounting table 103 includes, for example, a cylindrical base 1311 made of aluminum carbide. The base 13 1 is disposed on the floor of the processing chamber 10 2 in a state of being insulated by the insulating member 13 1 a. A high frequency power supply 133 for applying a high frequency for bias is connected to the base 13 1 via a capacitor CI 1 and a coil LI 1. On the side wall of the mounting table 103, a baffle plate 134 for forming a uniform exhaust flow in the circumferential direction of the wafer W at the time of exhaust is disposed. The baffle plate 134 is a ring-shaped plate member extending from the mounting table 1-03 to the vicinity of the inner wall surface of the processing chamber 102. An electrostatic chuck 104 for adsorbing and holding the wafer W substantially horizontally is provided on the upper surface of the base 13 1. A focus ring 132 is provided so as to surround the periphery of the electrostatic chuck 104. The electrostatic chuck 104 is made of a dielectric material, for example, polyimide, alumina, or aluminum nitride, on both sides of the conductive sheet-like chuck electrode 141. It has a structure sandwiched between insulating layers 142. Chuck electrode 144 is selected between DC power supply 144 and ground via switch SW 11 Connected. When a DC voltage (chuck voltage) is applied from the DC power supply 144 to the chuck electrode 1441, a Coulomb force is generated between the electrostatic chuck 104 and the wafer W. Thus, the wafer W can be suction-held on the mounting table 103. When releasing the suction of the wafer W, the switch SW11 is switched to release the electric charge near the electrostatic chuck 104 to the ground.

A residual charge monitor 144 serving as a residual charge monitoring means is provided in the circuit connecting the chuck electrode 144 and the DC power supply 144. The control unit 107 via the residual charge monitor 144 can grasp the progress of the electrostatic chuck 104 in the following manner when the static electricity is removed from the electrostatic chuck 104. That is, for example, the charge amount Q 1 flowing when the switch SW 11 is connected to the DC power supply 144 is stored. Next, the amount of charge Q 2 flowing when the switch SW 11 is switched to the ground side is measured. Then, the charge amount Q 2 is subtracted from the charge amount Q 1 (Q 1 −Q 2), and the charge remaining in the electrostatic chuck 104 is obtained.

An elevating member 105 is provided inside the mounting table 103 in order to transfer the wafer W to and from an external transfer arm (not shown). The elevating member 105 constitutes a detaching means for detaching the wafer W from the surface 144 of the electrostatic chuck 104 after the processing is completed. The elevating member 105 includes a plurality of, for example, four support pins 153, and these are disposed in a hole 155 formed in the mounting table 103. The support pin 1553 extends in the vertical direction, and is attached to the common shaft 151 via the connecting member 152 in the mounting table 103. Shaft 15 1 is, for example, It is moved up and down by a drive mechanism 154 including an air cylinder and a ball screw mechanism, so that the support pin 153 protrudes and sinks against the surface 144 of the mounting table 103.

FIG. 5 is a schematic plan view showing the positional relationship between the wafer W, the electrostatic chuck 104 and the support pins 153 in the apparatus shown in FIG. As shown in FIG. 5, the support pins 153 are, for example, equidistant from the center 156 of the electrostatic chuck 104 (also the center of the wafer W) and along the circumferential direction. It is located at such a location. In addition, since each support pin 153 has the same height at the tip, when ascending, the wafer W placed on the surface 144 can be lifted in a horizontal posture.

The elevating member 105 also functions as a static eliminator after the electrostatic chuck 104 releases the suction. Although details will be described later, for example, the support pins 15 3 are vibrated by the piezoelectric element 16 1 provided at the upper end of the shaft 15 1, and are brought into contact with the wafer W in such a state. Encourages static elimination of both electrostatic chuck 104 and wafer W. The piezoelectric element 16 1 is connected to an AC power supply 16 2 via a capacitor C 12 and a coil L 12. The base 13 1 and the piezoelectric element 16 1 are grounded via a common resistor R 11 and a switch SW 12. The operation of the driving mechanism 154 and the piezoelectric element 161 and the switching of the switches SW11 and SW12 are controlled by the control unit 107.

Next, the operation of the processing device shown in FIG. 4 performed under the control of the control unit 107 will be described. First, open the gate valve G and open the adjacent vacuum atmosphere through the opening 122 (or 123). The load chamber (not shown) that is set to the desired condition and the processing chamber 102 are communicated. Next, a substrate to be processed, in this example, a semiconductor wafer (silicon wafer) W, is carried into the processing chamber 102 from the load lock chamber by a transfer arm (not shown). Next, the transfer arm and the support pin 15 3 (elevating member 105) cooperate with each other to put the surface on the mounting table 103, that is, the surface 14 of the electrostatic chuck 104. 3 Place wafer W on top. Next, the switch SW 11 is switched to the DC power supply 144 side to turn on the electrostatic chuck 104, and the wafer W is attracted to the surface of the mounting table 103.

On the other hand, after the transfer arm is withdrawn from the processing chamber 102, the gate valve G is closed, and the inside of the processing chamber 102 is evacuated via the exhaust pipe 120. Next, a processing gas such as C 4 F ₈ gas, for example, C 4 F ₈ gas is supplied to the wafer W while evacuating, and the pressure in the processing chamber 102 is set to, for example, Adjust so that it is maintained at 1 to 50 Pa. Next, a high-frequency voltage is applied between the mounting table 103 serving as the lower electrode and the shower head 122 serving as the upper electrode by the high-frequency power supply 133 to convert the processing gas into plasma. The density of the plasma is increased by the magnets 124 and 125. Using the plasma generated in this way, for example, a silicon oxide film on the surface of the Ueno and W surfaces is etched. After performing the etching for a predetermined time, the high frequency power supply 133 is stopped. Then, the process proceeds to a step of detaching the wafer W from the electrostatic chuck 104.

FIG. 6 shows a method of detaching the wafer W from the electrostatic chuck 104 under the control of the control unit 107 in the apparatus shown in FIG. It is a flowchart. 7A, 7B, and 7C are cross-sectional views illustrating a method of detaching the wafer W in the order of steps.

First, switch SW11 is switched to the ground side, and switch SW12 is closed to remove static electricity from electrostatic chuck 104. Further, the power supply to the piezoelectric element 161 is started, the piezoelectric element 161 is oscillated at a preset vibration frequency, and the lifting member 105 is oscillated (step S11). At this time, as shown in FIG. 7A, the height of the elevating member 105 is set such that the tip of the support pin 153 is buried inside the mounting table 103. The value of the vibration frequency of the piezoelectric element 161 varies depending on the size and type of the wafer, the type of the film formed on the wafer surface, or the contact pressure between the wafer W and the support pins 153 described later. . However, the value of the vibration frequency is set within a range where the wafer W does not move from the suction surface and only static elimination proceeds.

Next, the lifting member 105 is raised by the drive mechanism 154 (step S12). At this time, the control unit 107 determines whether or not the wafer W has come into contact with the support pins 153 (step S13), and until the contact is obtained, the elevating member 10 5 is continuously increased (step S14). Alternatively, the control unit 107 can continuously raise the elevating member 105 by a predetermined amount so that the wafer W and the support pin 1553 come into contact with each other. You.

When the wafer W comes into contact with the support pin 153 at a predetermined contact pressure (or when the lift of the lifting member 105 reaches a predetermined amount), the lifting of the lifting member 105 stops. While the piezoelectric element The vibration according to 16 1 is continued (step S 15). Therefore, as shown in FIG. 7B, the surface of the wafer W vibrates through the support pins 15 3, and as a result, the residual charges near the surface 14 3 are gradually discharged by the mechanism described later. Is done. The control unit 107 monitors the residual charge by the residual charge monitor 144 before the wafer W comes into contact with the support pins 153, and determines the residual charge and a predetermined set value. (Step S16). The power supply from the AC power supply 162 to the piezoelectric element 161 continues until the residual charge becomes equal to or less than the set value, and discharge is promoted (Step S17) ₀

When the residual charge becomes equal to or less than the set value, the supporting pins 15 3 are raised again by the driving mechanism 15 4 and detached from the mounting table 10 3 so as to push up the wafer W. (Step S18). It should be noted that the set value of the residual charge can be a level when the negative charge on the back surface of the wafer W is completely neutralized. Alternatively, this set value can be set to a level at which the charge is removed to the extent that the suction force that does not cause the detachment abnormality even when the wafer W is pushed up by the support pin 153 is left.

The driving mechanism 154 is stopped when the support pin 153 is raised to a predetermined height. Also, the power supply to the piezoelectric element 161 is stopped, and the vibration of the support pin 153 is stopped (step S19: Fig. 7C). Thereafter, the wafer W is unloaded from the processing chamber 102 in the reverse order of the loading.

FIG. 8 is an enlarged cross-sectional view showing an electrical relationship between the wafer W and the electrostatic chuck 104 in the apparatus shown in FIG. Figure 4 The mechanism of static elimination when the wafer W is detached in the illustrated apparatus will be described with reference to FIG.

The surface 144 of the electrostatic chuck 104 and the back side of the wafer W both have irregularities as shown in FIG. 8 when viewed microscopically. In the vicinity of the approaching portions P 1 and P 2 where the two irregularities approach, the binding force of the electric charge (for example, the negative charge on the wafer side and the positive charge on the electrostatic chuck side) is strong, and many It is considered that the charges gathered to generate a strong adsorption force. In such a state, a Coulomb force (attraction), in which the positive charge of the electrostatic chuck 104 and the negative charge of the wafer W attract each other, acts, and the wafer W becomes electrostatic chuck 104. Is electrostatically attracted.

Therefore, the wafer W is vibrated to slightly increase the distance between the approaching parts Pl and P2 (for example, to such a degree that the wafer W does not detach and bounce), thereby reducing the capacitance in the area. Make Then, the negative charges at the approaching part P 1 are released from the constraint of the Coulomb force, and can freely move around in the silicon wafer W as a semiconductor. As a result, the negative charges are discharged in the direction of lower resistance, and the residual charges on the back surface of the wafer W decrease. Most of the above-mentioned negative charges go to the processing chamber 102 through the gas space, and a part of them is placed on the mounting table 103 (support pins 153, base 131, etc.). It is considered that it works toward the ground contact.

According to the present embodiment, the piezoelectric element 161 is provided on the elevating member 105 for detaching the wafer W adsorbed on the electrostatic chuck 104, and the piezoelectric element 161 is provided via the support pin 153. Vibrates the wafer W. For this reason, the lifting member 105 is raised and the vicinity of the surface 144 is raised. Discharge can be performed quickly by dispersing the residual charges located nearby. As a result, the wafer W can be desorbed in a short time while preventing abnormal desorption.

Since the four support pins 15 3 are vibrated, substantially uniform vibration can be applied to the entire surface of the wafer W, and uniform charge removal can be performed. Since the vibration of the wafer W is performed at the pin points via the support pins 153, for example, the energy required for the vibration is smaller than when the vibration is applied to the entire surface of the mounting table 103. Need to be reduced. Before starting static elimination, support pins

Since 153 is vibrated, static elimination can be performed while maintaining similar conditions almost consistently from the start (at the time of contact) to the end (at the time of detachment) of the vibration. It should be noted that the vibration frequency of the piezoelectric element 161 does not need to be constant at all times. For example, the vibration frequency is gradually changed according to the contact pressure between the wafer W and the support pin 1553. Is also good.

Since the progress of static elimination is checked using the residual charge monitor 144, the desorption operation can be started at appropriate timing. Note that the timing of the transition from the charge removal to the desorption operation is not limited to the residual charge monitor 144. For example, a configuration may be adopted in which a timer is provided in the control unit 107 so that the desorption operation is started at a time measured in advance.

A low resistance grounding line dedicated to static elimination may be provided separately from the route shown in FIG. 4 to promote static elimination. The place where the piezoelectric element 16 1 is installed may be, for example, at or near the tip of the support pin 15 3. Supports piezoelectric element 1 6 1 When it is provided at the tip of the pin 15 3, it is preferable to coat the surface of the tip with an insulating film. In performing the desorption operation of the wafer W, the atmosphere in the processing chamber may be adjusted so as to be an atmosphere that is advantageous for facilitating charge removal. In this case, for example, the type, pressure or flow rate of the purge gas supplied into the processing chamber, or the temperature of the atmosphere can be adjusted.

According to the above-described first and second embodiments, after the voltage application to the chuck electrode is stopped, the electric charge remaining on the rear surface of the substrate to be processed is removed while the elevating member is raised, and the electric charge is removed. A series of steps of detaching a processing substrate can be performed almost simultaneously. For this reason, the desorption time can be significantly reduced while preventing desorption abnormalities in the electrostatic chuck.

In the first and second embodiments described above, etching is mentioned as an example of the processing. However, these embodiments are also applied to the case of performing processing such as CVD, asshing, and sputtering. can do. '

Claims

The scope of the claims

1. A semiconductor processing apparatus for performing semiconductor processing on a substrate to be processed having a conductor or a semiconductor back surface,

A processing chamber for storing the substrate to be processed,

Is provided.

2. The detachment member is electrically conductive and detaches the substrate to be processed from the mounting table while being in contact with the back surface of the substrate to be processed. 2. The processing apparatus according to claim 1, further comprising: supplying the second polarity charge to the rear surface of the substrate to be processed via a member.

3. The charge supply unit connects the detaching member to a power supply and a grounding unit. 3. The processing apparatus according to claim 2, further comprising a switch to be selectively connected, wherein the switch is controlled by the control unit.

4. The monitor further comprises a monitor for monitoring the residual charge of the mounting table, wherein the control unit controls the detachment member after the detection value of the residual charge detected by the monitor becomes equal to or less than a set value. 2. The processing apparatus according to claim 1, wherein the processing target substrate is detached from the mounting table.

5. A switch for selectively connecting a chuck electrode of the electrostatic chuck to a power supply and a grounding unit, wherein the monitor is connected between the chuck electrode and a power supply; The processing apparatus according to claim 4, wherein the residual charge on the mounting table is monitored via the chuck electrode.

6. The control unit may further include a control unit configured to control the detachment member after a predetermined time has elapsed after supplying the charge of the second polarity to the back surface of the substrate to be processed by the charge supply unit. 2. The processing apparatus according to claim 1, wherein the substrate to be processed is detached from a table.

7. In a semiconductor processing apparatus for performing semiconductor processing on a substrate to be processed having a conductor or semiconductor back surface, a semiconductor substrate is removed from an electrostatic chuck that electrostatically attracts the back surface of the substrate to be processed on a mounting table. A method of detaching the substrate to be processed by a release member, wherein the back surface of the substrate to be processed is electrostatically attracted by the electrostatic chuck, and a second surface is formed on the rear surface. Generating a charge of one polarity; and

Stopping the application of voltage to the chuck electrode of the electrostatic chuck; Next, supplying a charge of a second polarity opposite to the first polarity to the back surface of the substrate to be processed;

Is provided.

8. The detaching member is electrically conductive and detaches the substrate to be processed from the mounting table while being in contact with the back surface of the substrate to be processed, and the method includes: 8. The method according to claim 7, wherein the second polarity charge is supplied to the back surface of the substrate to be processed.

9. The residual charge on the mounting table is monitored, and after the detection value of the residual charge becomes equal to or less than a set value, the substrate is detached from the mounting table by the detachment member. The method described in 7.

10. After a predetermined time has elapsed since the supply of the second polarity charge to the back surface of the substrate, the substrate is detached from the mounting table by the detachment member. The method of claim 7.

1 1. A semiconductor processing apparatus for performing semiconductor processing on a substrate to be processed,

A processing chamber for storing the substrate to be processed,

A mounting table for mounting the substrate to be processed in the processing chamber, and the mounting table having an electrostatic chuck for electrostatically adhering a back surface of the substrate to be processed;

The desorption for selectively detaching the substrate to be processed from the mounting table. Release member and,

A vibration supply unit that selectively supplies vibration to the elevating member; a control unit that controls operations of the detachment member and the vibration supply unit; Immediately before the substrate to be detached from the substrate, the vibration supply unit causes the substrate to be detached from the substrate via the detachment member in a state where the detachment member is in contact with the back surface of the substrate to be treated. Supplying the vibration to the processing substrate;

Is provided.

12. The process according to claim 11, wherein the detachment member is conductive and detaches the substrate to be processed from the mounting table by pushing up the substrate to be processed from the back surface side. apparatus.

13. The processing apparatus according to claim 11, wherein the vibration supply unit includes a piezoelectric element attached to the detachable member.

14. The detachment member includes a plurality of lifter pins connected to a common shaft in the mounting table, and the piezoelectric element is connected to the common shaft in the mounting table. Claims attached 1

3. The processing apparatus according to 3.

15. The monitor further comprising: a monitor for monitoring a residual charge of the mounting table, wherein the control unit is configured to perform the desorption after the detection value of the residual charge detected by the monitor falls below a set value. 13. The processing apparatus according to claim 11, wherein the substrate is detached from the mounting table by a member.

16. A switch for selectively connecting a chuck electrode of the electrostatic chuck to a power supply and a grounding unit, wherein the monitor is provided with a switch 16. The processing apparatus according to claim 15, wherein the processing apparatus is connected between the chuck electrode and a power supply, and monitors the residual charge of the mounting table via the chuck electrode.

17. In a semiconductor processing apparatus for performing semiconductor processing on a substrate to be processed, the processing target is separated by a detachable member from an electrostatic chuck that electrostatically attracts the back surface of the substrate to be processed on a mounting table. A method of detaching a substrate,

Stopping the application of voltage to the chuck electrode of the electrostatic chuck; and

Next, supplying vibration to the substrate to be processed via the detachment member in a state where the detachment member is brought into contact with the back surface of the substrate to be treated,

Is provided.

18. The method according to claim 17, wherein the detachment member is conductive and detaches the substrate to be processed from the mounting table by pushing up the substrate to be processed from the back surface side. .

19. The residual charge on the mounting table is monitored, and after the detection value of the residual charge becomes equal to or less than a set value, the substrate is detached from the mounting table by the detachment member. The method of claim 17.

20. The method according to claim 17, wherein the supply of the vibration to the detachment member is started before the detachment member comes into contact with the back surface of the substrate to be processed.