WO2008002089A1

WO2008002089A1 - Neutral particle beam generating apparatus with increased neutral particle flux

Info

Publication number: WO2008002089A1
Application number: PCT/KR2007/003150
Authority: WO
Inventors: Suk-Jae Yoo; Bong-Ju Lee
Original assignee: Korea Basic Science Institute
Priority date: 2006-06-29
Filing date: 2007-06-28
Publication date: 2008-01-03
Also published as: KR100754370B1

Abstract

The present invention relates to an apparatus for generating neutral particle beam with enhanced neutral particle flux. The apparatus of the present invention comprises a plasma discharging space inside which processing gases are converted into plasma ions through a plasma discharge, a metal plate which converts the plasma ions into neutral particles through collisions with the plasma ions, a plasma limiter which prevents the plasma ions and electrons from passing through and allows the neutral particles produced by collisions of the plasma ions with the metal plate to pass through, and a magnetron unit which applies magnetic field to the plasma discharging space, wherein the plasma discharging space is sandwiched between the metal plate and the plasma limiter, and the magnetron unit applies the magnetic field across the metal plate to the plasma discharging space to control plasma distribution. Preferably, the magnetron unit comprises a central pole and a side pole having a race track arrangement. The magnetic field applied across the metal plate increases density of the plasma ions near the metal plate. This improves the conversion efficiency of the plasma ions into the neutral particles to increase neutral particle flux.

Description

NEUTRAL PARTICLE BEAM GENERATING APPARATUS WITH INCREASED NEUTRAL PARTICLE FLUX

Technical Field

[1] The present invention relates to an apparatus for generating neutral particle beam.

More particularly, the present invention relates an apparatus for generating neutral particle beam for use in surface treatment of a substrate with the neutral particle beam. Background Art

[2] Plasma is a group of charged protons and electrons generated through a plasma discharge, and is being widely used in treating a surface of a substrate in a semiconductor manufacturing process, such as plasma etch and PECVD (Plasma Enhanced- Chemical Vapor Deposition). Nevertheless, the plasma processing method had suffered from a disadvantage that the plasma is a charged particle. For instance, use of charged particles for etching often tends to alter etch profile, damage a circuit formed on the substrate, or lead to voltage gradients which may damage the surface of a substrate.

[3] To overcome such a problem caused by the plasma processing method, systems using neutral particles are suggested. There are two main techniques to produce neutral particles from plasma. One is a charge exchange which produces neutral particles by collisions of the plasma with gas particles. The other is to produce the neutral particles by collisions of the plasma with a metal plate. As an example of the former technique, Japanese patent Nos. 2,606,551 and 2,842,344 may be mentioned as a reference. However, the neutral particles produced through the charge exchange between the plasma and the gas particles had drawbacks that the efficiency of transformation to neutral particles is low and that the directionality of neutral particles and colliding frequency are hard to control. Therefore, the technique to produce neutral particles by collisions of plasma ions with the metal plate is believed to be more desirable.

[4] US Patent No. 4,662,977 discloses a neutral particle beam generating apparatus for treating a surface of a substrate, comprising a plasma gun which produces plasma and directs the produced plasma to a predetermined direction, and a metal plate which converts plasma ions to neutral particles and redirects the neutral particles to the substrate. The system has an advantage of solving drawbacks of the plasma, but is not suitable for treating the surface of a substrate having a size of 8 inches or more, due to a small cross section of the incident neutral particle beams.

[5] WO 01/84611 filed by the present inventors discloses an apparatus for treating surfaces with neutral particle beams, comprising a high frequency electric power in- troducing part, a plasma generating part, a neutral particle generating part and a treating part that loads the target substrate. In the apparatus, high frequency electric power is introduced through the high frequency electric power introducing part, gases introduced into the plasma generating part are converted to plasma with the high frequency electric power, the plasma generated inside the plasma generating part are transformed into neutral particles through collisions of the plasma with a metal plate, and the neutral particles thus generated are used to treat the surface of a substrate. An advantage of the neutral particle beam generating apparatus is to generate uniform plasma that enables to treat targets with comparatively larger areas. WO 2004/036611 discloses a modified neutral particle beam generating apparatus that improves the conversion performance from plasma to neutral particle beams by forming inclined slits or inclined holes within the metal plate to increase the number of plasma collisions to the metal plate, and thereby improving the efficiency of surface treatment of targets. Herein, the inclined slits or inclined holes formed on the metal plate guarantee the collisions of the plasma with the metal plate and prevent plasma and electrons to reach the substrate. The neutral particle beam generating apparatus has advantages that, for example, a plasma discharging space guarantees uniform plasma generation with wider area, and that the effects caused by plasma ions and electrons unconverted to neutral particle is minimized, and that a highly directional neutral particle beams are produced. Nevertheless, according to the neutral particle beam generating apparatus, plasma sheath occurs within the inclined slits or inclined holes and interferes with the production of neutral particles. In other words, the direction of the plasma ions is interrupted by the imperfect sheath formed at the inclined slits or inclined holes and a large number of neutral particles from plasma ions is not reachable to the target.

[6] To overcome the above problems, WO 2005/053365 discloses a neutral particle beam generating apparatus comprising a plasma discharging space inside which processing gases are converted into plasma ions through a plasma discharge, a metal plate which converts the plasma ions into neutral particles through collisions, a plasma limiter which prevents plasma ions and electrons from passing through and allows the neutral particles produced by collisions of the plasma ions with the metal plate to pass through, and a treating housing inside which a substrate to be treated is located, wherein the plasma discharging space is sandwiched between the metal plate and the plasma limiter. With the configuration that the metal plate and the plasma limiter are separated by the plasma discharging space which positioned between them, the apparatus of WO 2005/053365 provides the following advantages. (1) Conversion of the plasma ions into neutral particles is not interfered by the plasma ions or electrons, which simplifies the generation of neutral particles; and (2) generation of neutral particles is enhanced to improve surface treatment efficiency. Disclosure of Invention

Technical Problem

[7] Our inventors have performed extended researches to provide improvements to the apparatus of WO 2005/053365. Throughout the researches, our inventors found new improvements that provide enhanced neutral particle flux. Technical Solution

[8] According to the present invention, there is provided an apparatus for generating neutral particle beam, comprising a plasma discharging space inside which processing gases are converted into plasma ions through a plasma discharge, a metal plate which converts the plasma ions into neutral particles through collisions, a plasma limiter which prevents plasma ions and electrons from passing through and allows the neutral particles produced by collisions of the plasma ions with the metal plate to pass through, and a magnetron unit which applies magnetic field to the plasma discharging space, wherein the plasma discharging space is sandwiched between the metal plate and the plasma limiter, and the magnetron unit applies the magnetic field across the metal plate to the plasma discharging space to control plasma distribution.

[9] According to another preferred embodiment of the present invention, there is provided an apparatus for generating neutral particle beam, wherein the plasma discharging space is positioned below the metal plate, the plasma limiter is positioned below the plasma discharging space, and the magnetron unit is positioned above the metal plate.

[10] According to more preferred embodiment of the present invention, there is provided an apparatus for generating neutral particle beam, wherein the magnetron unit comprises a central pole and a side pole having a race track arrangement into which the side pole surrounds the central pole.

[11] According to another more preferred embodiment of the present invention, there is provided an apparatus for generating neutral particle beam, wherein the magnetron unit is covered with a cover made of magnetic shielding agent to reinforce the magnetic field at inside of the plasma discharging space.

[12] According to further another preferred embodiment of the present invention, there is provided an apparatus for generating neutral particle beam, further comprising a bias voltage source that directs the plasma ions produced inside the plasma discharging space to the metal plate.

[13] According to still another preferred embodiment of the present invention, there is provided an apparatus for generating neutral particle beam, further comprising a collimator to collimate neutral particles which had passed through the plasma limiter. [14] According to further another preferred embodiment of the present invention, there is provided an apparatus for generating neutral particle beam, further comprising a sputtering unit that supplies vaporized neutral atoms to the plasma discharging space.

[15] According to further another preferred embodiment of the present invention, there is provided an apparatus for generating neutral particle beam, comprising: a) a reaction chamber with an opened lower part, comprising an inner space, a gas inlet port installed at side of the reaction chamber, a metal plate and a magnetron unit, wherein the inner space of the reaction chamber is a plasma discharging space, the metal plate is positioned at top of the plasma discharging space, and the magnetron applies magnetic field across the metal plate to the plasma discharging space, processing gases introduced into the plasma discharging space through the gas inlet port being converted into plasma ions through a plasma discharge in which density of the plasma ions is high near the metal plate with aid of the magnetic unit and then the plasma ions being converted into neutral particles by collisions with the metal plate; b) a plasma limiter located below the reaction chamber comprising holes or slits to pass the neutral particles through while interrupting the plasma ions and electrons from passing through; and c) a treating housing located below the plasma limiter inside which a substrate to be treated with the neutral particles is located.

[16] According to another preferred embodiment of the present invention, there is provided a neutral particle beam generating apparatus, further comprising a magnetic unit to impress magnetic field or an electric unit to impress electric field to the holes or slits of the plasma limiter to change pathway of the plasma ions and the electrons.

[17] According to further another preferred embodiment of the present invention, there is provided a neutral particle beam generating apparatus, further comprising a collimator to collimate the neutral particles which had passed through the plasma limiter at between the plasma limiter and the treating housing.

[18] According to yet another preferred embodiment of the present invention there is provided a neutral particle beam generating apparatus, wherein the plasma limit has holes or slits and the collimator has holes.

Advantageous Effects

[19] The neutral particle beam generating apparatus of the present invention has a simple structure and exhibits enhanced flux of the neutral particle beam. For instance, the apparatuses disclosed in WO 01/84611 and WO 2004/036611 had complicatedly structured reflecting panels in order to achieve conversion of plasma ions into neutral particles and exclusion of interference by plasma ions and electrons. To the contrary, the apparatus according to the present invention does not require such a complicated structure. The metal plate which converts plasma ions into neutral particles and the plasma limiter which allows the neutral particles to passing through and prohibits the plasma ions and electrons from passing through are separated by the plasma discharging space. Therefore, the conversion to neutral particles could be simplified and the interruption caused by the plasma ions and the electrons are easily prevented. As a result, the conversion efficiency to the neutral particles and the surface treatment efficiency are remarkably improved. Further, according to the present invention, the distribution of the plasma ions is suitably controlled by the magnetron unit, which further increases the flux of the neutral particles. Ten fold increases in terms of the flux of the neutral particles can be obtained compared with the conventional apparatus of WO 2005/053365. Particularly, the apparatus of the present invention with improved flux of the neutral particles can be suitably applicable to various semiconductor processing including lithography and pattern formation. Brief Description of the Drawings

[20] Fig. 1 is a cross-sectional view showing a preferred embodiment of the neutral particle beam generating apparatus in accordance with the present invention.

[21] Fig. 2 is a cross-sectional view showing another preferred embodiment of the neutral particle beam generating apparatus in accordance with the present invention.

[22] Fig. 3 is a cross-sectional view showing further another preferred embodiment of the neutral particle beam generating apparatus in accordance with the present invention.

[23] Fig. 4 is a perspective view showing preferred combination of a plasma limiter and a collimator used in the neutral particle beam generating apparatus in accordance with the present invention.

[24] Fig. 5 is a perspective view showing preferred embodiment of the arrangement of the magnetron unit used in the neutral particle beam generating apparatus in accordance with the present invention.

[25] Fig. 6 is a cross-sectional view showing preferred embodiment of the plasma limiter used in the neutral particle beam generating apparatus in accordance with the present invention.

[26] Fig. 7 is a cross-sectional view showing further another preferred embodiment of the neutral particle beam generating apparatus in accordance with the present invention. Mode for the Invention

[27] According to the preferred embodiment of the present invention, there is provided an apparatus for generating neutral particle beam, comprising a plasma discharging space inside which processing gases are converted into plasma ions through a plasma discharge, a metal plate which converts the plasma ions into neutral particles through collisions with the plasma ions, a plasma limiter which prevents plasma ions and electrons from passing through and allows the neutral particles produced by collisions of the plasma ions with the metal plate to pass through, and a magnetron unit which applies magnetic field to the plasma discharging space, wherein the plasma discharging space is sandwiched between the metal plate and the plasma limiter, and the magnetron unit applies the magnetic field across the metal plate to the plasma discharging space to control plasma distribution.

[28] Inside the plasma discharging space, processing gases are introduced and converted to plasma through a plasma discharge. In other words, plasma, as a group of plasma ions (or positive ions) and electrons, is generated within the plasma discharging space. At this point, the plasma could be generated through various methods. For instance, a capacitatively coupled plasma discharge, an inductively coupled plasma discharge, a helicon discharge using plasma wave, and a microwave plasma discharge can be applied. The inductively coupled plasma discharge which generates high density plasma under low operating pressure is desirable among them. Concerning the shapes of antenna used for the inductive coupled plasma discharge, please refer to Korean Patent Application Nos. 7010807/2000, 14578/1998, 35702/1999 and 43856/2001.

[29] The plasma ions produced inside the plasma discharging space are converted into neutral particles by collisions with the metal plate. As used herein, the term "a metal plate" should be understood as a plate composed of, or coated on to a plate with a metal that converts the plasma ions to the neutral particles through collisions. Preferably, the surface of the metal plate, where the plasma ions collide, is polished in order to guarantee elastic collisions. Examples of heavy metals to be used are tantalum (Ta), molybdenum (Mo), tungsten (W), gold (Au), platinum (Pt), stainless steel or alloys thereof, but are not limited thereto. Contrary to those of WO 01/84611 and WO 2004/036611, the metal plate does not require any holes for the pathway of neutral particles. That is because, although the metal plate collides with plasma ions and converts them to neutral particles, it does not function as a pathway for the produced neutral particles.

[30] The neutral particles produced by collisions with the metal plate are reflected, and enter into the plasma limiter via the plasma discharging space which positioned between the metal plate and the plasma limiter.

[31] The plasma limiter interrupts the plasma ions and the electrons from passing through and selectively allows the neutral particles to pass through. A passive limiting having holes or slits to limit the plasma ions and the electrons from passing through, or an active limiting in which magnetic or electric field is impressed to the holes and slits to control the moving direction of the charged plasma ions or electrons could be used. The neutral particles, which had passed through the plasma limiter, collide with a substrate located inside the treating housing and perform surface treatment including, for example, removal of organic materials or photo-resist from the substrate.

[32] In order to achieve enhanced surface treatment, the directionality of neutral particles needs to be suitably controlled. For instance, to form a predetermined pattern on a surface by the surface treatment, the directionality of neutral particles is very important. In this case, it is desirable to additionally install a collimator, which collimates the direction of neutral particles, at between the plasma limiter and the processing space. The collimator is configured to have multi holes to provide fixed directionality.

[33] One of the most distinguishing features of the present invention is that the neutral particle beam generating apparatus further comprises a magnetron unit that applied into the plasma discharging space across the metal plate. The magnetic field applied across the metal plate increases the density of the plasma ions near the metal plate. Particularly, the magnetron unit having race track arrangement in which a central pole is surrounded by a side pole forces the electrons to circulate around a mirror race track below the metal plate. The electrons circulating around the race track collide with neighboring neutral gases, which are not converted into the plasma, to produce plasma ions of the neighboring neutral gases. This increases the density of the plasma ions near the metal plate. As a result, the density of the plasma ions is increased near the metal plate. More detailed explanation will be given in the following.

[34] The neutral particle beam generating apparatus according to the present invention can be applicable to various surface treatment such as etching, ashing, formation of oxidized film, cleaning, and thin film deposition. As used herein, the term "surface treatment" various processes performed to manufacture structures including semiconductor apparatus, circuits or electrodes, which are connected to the semi-conductor, by forming semi-conducting layer, insulating layer or conducting layer with a predetermined pattern on a material to be processed such as semi-conductor wafer or liquid crystal substrate.

[35] In the following, the present invention will be more fully described referring to accompanying drawings.

[36] Fig. 1 is a cross sectional view showing a preferred embodiment of the neutral particle beam generating apparatus in accordance with the present invention. The apparatus illustrated in Fig.1 is comprised of a reaction chamber 100 with an opened lower part, a plasma limiter 200 positioned at the opened lower part of the reaction chamber 100 and a treating housing 300 positioned below the plasma limiter 200. The inner space of the reaction chamber 100 is a plasma discharging space 101. An antenna 102 to supply high frequency energy is installed in the plasma discharging space 101 and a gas inlet port 104 is installed at side of the reaction chamber 100. The reaction chamber 100 is operated as follows. First, processing gases are introduced into the plasma discharging space 101 through the gas inlet port 104 and the processing gases undergo a plasma discharge by the high power supplied through the antenna 102 and are converted into plasma 103. The plus ions (plasma ions) of the generated plasma are directed to the metal plate 106 positioned above the plasma discharging space 101, and there, the plasma ions collide with the metal plate 106 and are converted into neutral particles.

[37] Herein, the distribution of the plasma 103 is suitably controlled by the magnetic field applied across the metal plate 106 to the plasma discharging space 101. To accomplish this, a magnetron unit 500 is installed at the rear of the metal plate 106. Preferred embodiment of the arrangement of the magnetron unit 500 is shown in Fig. 5. As shown in Fig. 5, the magnetron unit 500 is comprised of a central pole 501 and a side pole 502 having a race track arrangement into which the side pole 502 surrounds the central pole 501. Herein, the upper of the central pole 501 has N pole (or S pole) and the bottom of the central pole 501 has S pole (or N pole), and the side pole 502 has complementary arrangement to the central pole 501. If necessary, the central pole 501 may be a permanent magnet and the side pole 502 may be a magnetic absorbent body. The magnetic field applied across the metal plate 106 by the magnetron unit 500 having race track arrangement controls the movement of the electrons 103a. In other words, it forces the electrons 103a to circulate around mirror race track inside the plasma discharging space 101. The electrons 103a rotating around mirror race track collides with neutral particles of the processing gas 103c that are not converted into plasma to produce plasma ions 103b. Then, the neutral gases are ionized. As a result thereof, the magnetic field applied across the metal plate 106 captures the electrons 103a around the race track and increases the density of the plasma ions 103b near the metal plate 106. The strength of the magnetic field by the magnetron unit 500 can be suitably adjustable depending upon the kind and the amount of the processing gas. Typically, the magnetic field has the strength of 1000 - 5000 gauss. At below 1000 gauss, the strength is not enough to capture the electrons. At above 5000 gauss, it is not cost effective. The magnetron unit 500 is generally made of the permanent magnet. In order to reinforce the magnetic field inside the plasma discharging space 101, the magnetron unit 500 is preferably covered with a cover 600. Preferably, the cover 600 has high magnetic susceptibility to focus the magnetic field into the plasma discharging space 101 and to reduce the loss thereof. Generally, soft iron is widely used as magnetic shielding agent.

[38] The plasma ions 103b of the plasma 103 produced inside the plasma discharging space 101 are directed to the metal plate 106 positioned at top of the plasma discharging space 101. Herein, the plasma ions 103b could be easily directed to the metal plate 106 by applying a minus bias voltage to the metal plate 106. The power of the bias voltage can be suitably adjustable depending upon the energy of the neutral particles to be required. Typically, the minus bias voltage has the strength of 10 - 100 V, preferably 30 - 50 V. When a minus bias voltage is impressed to the metal plate 106 , the plasma ions 103b are directed to the metal plate 106 substantially or perfectively perpendicularly and collide with the metal plate 106. The surface of the metal plate 106, where the plasma ions 103b collide, may be polished to improve conversion efficiency to neutral particles and to prevent energy loss during the collisions. By collision with the metal plate 106, the plasma ions 103b undergo neutralization such as auger neutralization. The neutral particles thus produced are reflected and enter into a substrate 301 of a treating housing 300 via the plasma discharging place 101 and perform surface treatment of the substrate 301. [39] The plasma limiter 200 is configured to have holes or slits 201. These holes or slits

201 allow the neutral particles to penetrate while interrupting the passage of the plasma ions and the electrons so that the neutral particles could pass through the plasma limiter 200 selectively and reach to the substrate 301 located in the treating housing 300. Although a material for the plasma limiter 200 is not specifically limited, a dielectric such as ceramic is desirable. The reason is that energy of the plasma ions and the electrons is absorbed when the plasma ions and the electrons collide with the side wall

202 of the plasma limiter 200, and thus, the adverse effects caused by the plasma ions and the electrons could be minimized. The plasma limiter 200 may also collide with the neutral particles without definite directionality and absorb their energy so that any adverse effect caused by neutral particles without definite directionality can be also eliminated. The passive limiting of the plasma ions and the electrons by the holes or slits 201 is dependent upon the diameter and the depth of holes or slits 201, and such an adjustment should be suitably performed.

[40] To effectively prevent the plasma ions 103b and the electrons 103a from passing through the plasma limiter 200, a means 203 for applying magnetic field or electric field to the plasma limiter 200 could be additionally installed at the plasma limiter 200. The means for applying magnetic or electric field 203 changes the moving direction of the plasma ions and the electrons, and further prevents them from reaching to the surface of a substrate. This limiting is called as "an active limiting". Fig. 6 shows preferred embodiment of the plasma limiter 200 used in the active limiting. As shown in Fig. 6, the plasma limiter 200 preferably comprises a magnet 203a at a center to apply the magnetic field into the holes or slits 201, conductive metal membranes 203b positioned at both surfaces of the magnet 203a to apply the electric field into the holes or slits 201, and dielectric membranes 204 positioned at both surfaces of the conductive metal membranes 203b to insulate the conductive metal membranes 203b. In order to reduce the loss of the magnetic field applied by the magnet 203a, a magnetic shielding film (not shown) may be formed at bottom of the magnet 203a. As a magnetic shielding agent, any one well known in the art may be used. Preferable is soft iron. The conductive metal membranes 203b is connected to a power supply (not shown). Each of the dielectric membranes 204 may be formed of an insulating material or by oxidizing the surface of the conductive metal membrane 203b. The conductive metal membrane 203b may be partially formed at surface of the magnet 203b. If necessary, the magnetic shielding film may be used as conductive metal membrane 203b. Preferably, the strength of the magnetic field is 1000 - 5000 gauss, and the strength of the electric field is 10 - 100 V having higher potential than that of the plasma discharging space.

[41] The neutral particles, which are protected from interruptions of the plasma ions and the electrons by "the passive limiting" or "the active limiting", perform surface treatment of the substrate 301 installed inside the treating housing 300. For instance, the neutral particles collide with the residual products, which are absorbed or remained on a substrate (for instance, a wafer) 301, and remove them. At this point, the neutral particles are not charged particles and they cause no damage to the substrate 301. The unexplained reference number 302 is a target holder moving up and down by operation of an elevating device connected to a elevating axis (not shown) so that it can carry in the substrate 301 such as a wafer to be newly processed and carry out the processed substrate 301. Meanwhile, the target holder 302 may be horizontally moved by a motor (not shown). This can prevent forming a blind spot caused by local introduction of the neutral particles onto the surface of the wafer. The unexplained reference number 303 is a gas outlet port connected to a vacuum pump (not shown) and maintains the inner pressure of the treating housing 300 at about 1 mTorr.

[42] The processing gases can be suitably chosen regarding the purpose of the surface treatment, which is well known to a person of ordinary to which the present invention pertains. For example, for resist removal or cleaning of organic substances from the substrate 301, it is preferred to use oxygen, ozone, an air, carbon dioxide (CO ), a steam or nitric oxide (N O). In addition, for etching silicon, it is effective to use CF or a chlorinated gas. For reducing metal oxides, it is possible to use a reducing gas such as hydrogen or ammonia. Further, in Si thin film formation, Si-containing gas such as SiH may be used.

[43] Although Fig. 1 shows an example of plasma generation by the inductively coupling plasma discharge, a capacitatively coupled plasma discharge, a helicon discharge using plasma wave and a microwave plasma discharge could be widely applied, under the condition of in situ generation of plasma ions by a discharge in the plasma discharging space and neutral particles generation by collisions of the produced plasma particles with the metal plate. Besides the various applications of the plasma discharging techniques, the plasma ions could be directed to the metal plate 106 by applying a plus bias voltage to the reaction chamber 100, instead of applying the minus bias voltage to the metal plate 106. Applying a minus bias voltage directs the positively charged plasma ions to the metal plate 106 by attraction. To the contrary, a plus bias voltage directs the plasma ions to the metal plate 106 by repulsion.

[44] According to the neutral particle beam generating apparatus of the present invention, an additive gas may be additionally supplied into the treating housing 300 in combination with the neutral particles of the processing gases in order to assist surface treatment. This is specifically explained in WO 2004/036611.

[45] In the above, the neutral particle beam generating apparatus comprises the metal plate 106 additionally installed above the plasma discharging space 101, but it is also possible to use the inner upper wall of the reaction chamber 100 asa metal plate by being formed of a heavy metal or coating a heavy metal thereon. Fig. 2 shows such an example. In Fig. 2, instead of additionally installing the metal plate 106, the inner upper wall of the reaction chamber 100 coated with a heavy metal is used as the metal plate 106, and a minus bias is applied thereto. And the plasma 103 generated in the plasma discharging space 101 collides with the inner upper wall, having a heavy metal coating to act as a metal plate 106, and produces neutral particles. Herein, the inner upper wall is insulated electrically with the other side walls of the reaction chamber 100 by insulators 107', 107". The reference numerals, which are not specifically explained, are same as the neutral particle beam generating apparatus shown in Fig. 1.

[46] Fig. 3 shows further another preferred embodiment of the neutral particle beam generating apparatus in accordance with the present invention. The apparatus illustrated in Fig. 3 is comprised of a reaction chamber 100 with an opened lower part, a plasma limiter 200 located at the opened lower part of the reaction chamber 100, a treating housing 300 located below the plasma limiter 200 and a collimator 400 located at between the plasma limiter 200 and the treating housing 300. Explanation to the reaction chamber 100, the plasma limiter 200 and the treating housing 300 is omitted because they are the same as those described in Fig. 1. The collimator 400, located at between the plasma limiter 200 and the treating housing 300, collimates the neutral particles passed through the plasma limiter 200 to improve the directionality of the neutral particles. The collimator 400 is configured to have multi holes 401. The neutral particles, which had collided with the side wall 402 of the holes 401 more than once, loose their energy during collision, and can no longer perform their role. Therefore, of the neutral particles which had penetrated the collimator 400, the ones perpendicular to the holes 401 can be solely used. As thus, the directionality of the neutral particles is improved by the collimator 400. [47] Fig. 4 is a perspective view showing a preferred combination of the plasma limiter and the collimator. The plasma limiter 200 in Fig.4 has slits formed between flat panels 204 formed of ceramic, and the collimator 400 has holes 401 at a position corresponding to the slits 201 of the plasma limiter 200. The slits 201 formed in the plasma limiter 200 improve the penetrating efficiency of the neutral particles, and the plasma ions and the electrons are interrupted from passing through the slits 201 by impressing the magnetic field created by the magnet 203. And holes 401 formed in the collimator 400 improve the directionality of the neutral particles. Interference by the plasma ions and the electrons is effectively excluded by the combination, and the neutral particles having collimated directionality perform surface treatment of the substrate. The neutral particles with improved directionality by the combination can be usefully applicable to various surface treatment including bonding, etching and ashing. The neutral particle may be used for photo-resist removal on a substrate 301 with a stencil mask. Meanwhile, although the plasma limiter and the collimator are presented as a hexahedron shape in Fig.4, it can be changed to various shapes such as cylindrical or oval shape.

[48] The neutral particle generating apparatus of the present invention may be used for the production of neutral particles of neutral atoms, in combination of a sputtering unit that supplies vaporized neutral atoms to the plasma discharging space. Such an embodiment is suggested in Fig. 7. As shown in Fig. 7, a sputtering unit 700 is installed at side wall of the reaction chamber 100. The sputtering unit 700 supplies vaporized neutral atoms to the plasma discharging space 101. Production of neutral particles of the neutral atoms supplied from the sputtering unit 700 is as follows. Firstly, processing gases are introduced into the plasma discharging space 101 through the gas inlet port 104 and the processing gases undergo a plasma discharge to produce plasma 103 as a group of plasma ions and electrons. Herein, the distribution of the plasma 103 is suitably controlled by the magnetic field applied by the magnetron unit 500. Specifically, the magnetic field applied by the magnetron unit 500 having the race track arrangement captures the electrons around the mirror race track, as shown in Fig. 5. With regard to this point, please refer to the detailed description mentioned in Fig. 5. In this circumstance, the vaporized neutral atoms 105 supplied by the sputtering unit 700 are also present in the plasma discharging space 101. The electrons may collide with the vaporized neutral atoms 105, thereby producing cations 105a of the vaporized neutral atoms 105. The cations 105a of the vaporized neutral atoms 105 is directed to the metal plate 106 and collide with the metal plate 106 to produce neutral particles of the neutral atoms 105 supplied from the sputtering unit 700. The reference numerals, which are not specifically explained in Fig. 7, are same as the neutral particle beam generating apparatus shown in Figures 1 to 3. [49] The neutral particle beam generating apparatus as shown in Fig. 7 is particularly suitable for the production of neutral particles of neutral atoms in a solid state, and applicable to thin film growth, this film deposition and pattern formation. For example, by supplying argon or nitrogen that does not cause damage to the substrate 301 as a processing gas and sputtering vaporized silicon atoms from the sputtering unit 700, neutral particle beam of silicon atoms can be obtainable to accomplish thin film formation or pattern formation on the substrate 301. The sputtering unit 700 produces vaporized neutral atoms 105 through energy shock to a solid source. Specifically, the sputtering unit 700 sputters the vaporized neutral atoms 105 to the plasma discharging space 101 by laser irritation to the solid source, attack of accelerated atoms to the solid source and heating of the solid source. As a solid source, solid carbon lump, silicon membrane or metal film may be used. Fig. 7 exemplifies the embodiment in which one sputtering unit 700 was equipped with. But, this is just an example. The number of the sputtering unit 700 can be suitably adjustable in a range of 1 to 6. In order to increase the uniformity of the neutral particle beam of the neutral atoms, preferably two or more sputtering units are installed in a symmetric arrangement at the side wall of the reaction chamber 100.

[50] As described, it should be evident that the present invention can be implemented through a variety of configurations in the aforementioned technical field without affecting, influencing or changing its spirit and scope of the invention. Therefore, it is to be understood that the examples and applications illustrated herein is intended to be in the nature of description rather than of limitation. Furthermore, the meaning, scope and higher conceptual understandings of the present patent application as well as modifications and variations that arise from thereof should be understood to be extensions to this current application.

Claims

[1] An apparatus for generating neutral particle beam, comprising a plasma discharging space inside which processing gases are converted into plasma ions through a plasma discharge, a metal plate which converts the plasma ions into neutral particles through collisions with the plasma ions, a plasma limiter which prevents the plasma ions and electrons from passing through and allows the neutral particles produced by collisions of the plasma ions with the metal plate to pass through, and a magnetron unit which applies magnetic field to the plasma discharging space, wherein the plasma discharging space is sandwiched between the metal plate and the plasma limiter, and the magnetron unit applies the magnetic field across the metal plate to the plasma discharging space to control plasma distribution.

[2] The apparatus as set forth in claim 1, wherein the plasma discharging space is positioned below the metal plate, the plasma limiter is positioned below the plasma discharging space, and the magnetron unit is positioned above the metal plate.

[3] The apparatus as set forth in claim 1, wherein the magnetron unit comprises a central pole and a side pole having a race track arrangement into which the side pole surrounds the central pole.

[4] The apparatus as set forth in claim 1, wherein the magnetron unit is covered with a cover made of magnetic shielding agent to reinforce the magnetic field applied to inside of the plasma discharging space.

[5] The apparatus as set forth in claim 1, further comprising a collimator positioned below the plasma limiter to collimate the neutral particles which had passed through the plasma limiter.

[6] The apparatus as set forth in claim 1, further comprising a sputtering unit that supplies vaporized neutral atoms to the plasma discharging space.

[7] The apparatus as set forth in claim 5, wherein the plasma limit is configured to have holes or slits and the collimator is configured to have holes.

[8] An apparatus for generating neutral particle beam, comprising: a) a reaction chamber with an opened lower part, comprising an inner space, a gas inlet port installed at side of the reaction chamber, a metal plate and a magnetron unit, wherein the inner space of the reaction chamber is a plasma discharging space, the metal plate is positioned at top of the plasma discharging space, and the magnetron applies magnetic field across the metal plate to the plasma discharging space, processing gases introduced into the plasma discharging space through the gas inlet port being converted into plasma ions through a plasma discharge in which density of the plasma ions is high near the metal plate with aid of the magnetic unit and then the plasma ions being converted into neutral particles by collisions with the metal plate; b) a plasma limiter located below the reaction chamber comprising holes or slits to pass the neutral particles through while interrupting the plasma ions and electrons from passing through; and c) a treating housing located below the plasma limiter inside which a substrate to be treated with the neutral particles is located.

[9] The apparatus as set forth in claim 8, wherein the magnetron unit comprises a central pole and a side pole having a race track arrangement into which the side pole surrounds the central pole. [10] The apparatus as set forth in claim 8, further comprising a collimator positioned at between the plasma limiter and the treating housing to collimate the neutral particles which had passed through the plasma limiter. [11] The apparatus as set forth in claim 8, further comprising a sputtering unit at side wall of the reaction chamber that supplies vaporized neutral atoms to the plasma discharging space.