WO2019042208A1

WO2019042208A1 - System and method for optical measurement

Info

Publication number: WO2019042208A1
Application number: PCT/CN2018/101861
Authority: WO
Inventors: 陈鲁; 张凌云; 张鹏斌
Original assignee: 深圳中科飞测科技有限公司
Priority date: 2017-08-31
Filing date: 2018-08-23
Publication date: 2019-03-07
Also published as: CN109425619B; CN109425619A

Abstract

A system and a method for optical measurement are provided. The system for measurement comprises: an incident light generating unit, configured to generate incident light for performing measurement on a measurement target; a reflected light detection unit, configured to receive reflected light from the measurement target and determine a corresponding measurement result; and a processing unit, configured to specify a measurement path using a light spot formed on the surface of the measurement target by the incident light and to perform measurement on the measurement target, wherein the processing unit determines the distribution of defects in the measurement target on the basis of the measurement result. The system for measurement has a simple structure, a fast detection speed, and low cost. It also generates less stray light and has higher detection sensitivity.

Description

Optical measurement system and method

Technical field

The invention belongs to the field of packaging technology detection, and in particular relates to an optical measuring system and method relating to detecting wafer defects.

Background technique

Chip cracks are one of the most deadly failure modes of integrated circuits. Large stresses in chip processing or constant changes in temperature during operation can cause chip cracks to continue to extend until the product fails. As a result, manufacturers often try to find it at the beginning of a chip crack and filter out cracked products to reduce costs and improve product yield.

The chip crack initially occurs in the silicon substrate portion on the back side of the chip, and exists in the form of wafer cracks. Since the silicon wafer is very thin and brittle, the process of thinning, cutting, packaging, etc. may cause wafer cracks. Therefore, the distribution of cracks has different characteristics corresponding to different processing techniques. For example, the wafer crack can be internal cracking, edge cracking, chipping notch or edge chamfering. It can be seen that some of the cracks are completely hidden inside the wafer, even with a high power microscope. Therefore, how to quickly detect wafer cracks in industrial production has become an important issue to be solved in semiconductor production.

Currently used wafer crack detection methods can be classified into non-optical methods as well as optical methods. A typical example of a non-optical method is an ultrasonic inspection method, which is based on the presence of cracks affecting the amplitude of the ultrasonic waveform, and has a good effect. However, ultrasonic testing requires placing the chip into a liquid, which may cause chip contamination and slow detection. Optical methods can generally be divided into three categories: (1) backlight detection method, the light source and the detector are respectively located on both sides of the chip, and the crack detection is realized by detecting the signal light transmitted through the chip, but it requires the transmittance of the tested chip. Higher, only can measure the die, often used in the grinding process; (2) light / electroluminescence detection method, the method requires the sample to be tested with the corresponding illuminating medium, generally used for solar chip detection; (3) infrared display Micro-imaging detection method, which is imaged by vertical illumination of infrared light source and receiving reflected light. However, the area array detector is an essential component of imaging measurement, and the existing infrared band area array detectors have slow response speed. The disadvantage of expensive price, coupled with the need to use a large numerical aperture objective lens to ensure imaging accuracy, resulting in a small single imaging field of view, so the speed and cost of infrared microscopic imaging seriously restrict its application. In addition, the technical solution using circular spot imaging has a large amount of stray light, which is very easy to cover the crack imaging, resulting in undetectable.

Therefore, there is a need for a crack detection method that is fast and accurate.

Summary of the invention

The present invention is directed to the above problems, and provides an optical measurement system and method for measuring a workpiece based on a line beam.

An aspect of the invention provides an optical measurement system comprising: an incident light generating unit configured to generate incident light for measuring an object to be tested; and a reflected light detecting unit configured to receive from the to-be-tested Reflecting light of the object and determining a corresponding measurement result; and processing unit, and configured to measure the object to be tested by using a spot formed on the surface of the object to be measured by the incident light to specify a measurement path, The processing unit determines a distribution of the defect in the object to be tested based on the measurement result.

In an embodiment, the measurement system further includes a load bearing unit configured to carry the object to be tested.

In one embodiment, the incident light is a line beam.

In one embodiment, the incident light is transparent with respect to the object to be tested.

In one embodiment, the processing unit is communicatively coupled to the carrier unit and/or the incident light generating unit to adjust a relative angle between the carrier unit and the incident light generating unit such that at least A specified measurement path is measured for the object to be measured.

In one embodiment, the reflected light detecting unit includes at least one line array detector to receive the reflected light.

In one embodiment, the specified measurement path includes a first specified measurement path and a second specified measurement path, and the processing unit is configured to measure the object to be tested by using the first specified measurement path And determining a first set of measured values; measuring the object to be tested by using the second specified measuring path, thereby obtaining a second set of measured values.

In one embodiment, the incident light forms a first spot on the surface of the object to be tested when measured according to the first specified measurement path, and the incident light is measured according to the second specified measurement path. Forming a second spot on the surface of the object to be tested, an angle α between the distribution of the first spot on the surface of the object to be tested and the distribution of the second spot on the surface of the object to be tested is greater than 0° and less than 180° .

In one embodiment, the angle a is greater than 0° and less than or equal to 90°.

The angle α of the distribution of the first spot on the surface of the object to be tested and the distribution of the second spot on the surface of the object to be tested are generated by the rotation angle α of the carrying unit relative to the incident light generating unit, or The incident light generating unit is generated with respect to the carrying unit rotation angle α.

In one embodiment, the processing unit is configured to determine a distribution of the defect in the object to be tested based on at least the first set of measured values and the second set of measured values. For example, the defect and the corresponding wafer position for each test can be determined according to the measurement path and the data storage order. By comparing the locations where cracks are detected twice, the repetitive signals are eliminated, giving the distribution of cracks in the wafer.

In one embodiment, the distribution of the defect in the object to be tested includes a position of the defect in the object to be tested, and a size of the defect.

In one embodiment, the direction of extension of the spot is parallel to the direction of extension of the defect. In general, the distribution of defects in different materials has different characteristics. Therefore, before the measurement, the distribution of incident light on the surface of the object to be tested can be determined according to the extension characteristics of the defects in the object to be tested. Improve measurement resolution. The specified plane here can be based on the characteristics of the defect. For the purposes of the present invention, defects may include cracks, bubbles, missing corners, and the like. In the case of cracks, cracks generally extend along the axial direction of the crystal lattice. Therefore, by two inspections, each inspection causes the line spot to extend in an axial direction parallel to the crystal lattice, thereby determining whether or not the wafer exists. crack.

Another aspect of the present invention provides an optical measuring method comprising: detecting an object to be tested by a specified path by incident light; and based on reflected light generated by the object to be tested based on the incident light Determining whether the object to be tested includes a defect.

In one embodiment, the incident light is a line beam.

In an embodiment, the specified path includes a first specified path and a second specified path.

In one embodiment, the incident light forms a first spot on the surface of the object to be tested when measured according to the first specified measurement path, and the incident light is measured when measured according to the second specified measurement path. The surface of the object forms a second spot, and an angle α between the distribution of the first spot on the surface of the object to be tested and the distribution of the second spot on the surface of the object to be tested is greater than 0° and less than 180°.

In one embodiment, the angle a is greater than 0° and less than or equal to 90°. It can be understood that when the object to be tested is a wafer, since the axial directions of the crystal lattices are perpendicular to each other, the angle α between the first light spot and the second light spot may be equal to 90°.

In one embodiment, the object to be tested is measured by the first specified path, thereby determining a first set of measured values; and the object to be tested is measured by the second specified path, thereby determining Two measured value groups.

In one embodiment, the defect is determined in the test object based on at least an extension feature of the defect in the object to be tested, the first set of measured values, and the second set of measured values Distribution.

In one embodiment, the direction in which the incident light is formed on the surface of the object to be tested extends parallel to the direction in which the defect extends in the object to be tested.

By adopting the technical solution of the present invention, the measurement object can be measured in a non-contact manner, and the measurement speed is very fast, and can be used for process monitoring in the production process. In addition, since the present invention uses reflected light as the signal light, the pattern distribution on the wafer has little effect on the detection result, and the wafer crack in any type and any process can be measured.

DRAWINGS

The embodiments are shown and described with reference to the drawings. These figures are used to clarify the basic principles and thus only show the necessary aspects for understanding the basic principles. These drawings are not to scale. In the drawings, like reference characters indicate like features.

Figure 1a is a schematic view of the reflection in the wafer without cracks;

Figure 1b is a schematic view of the reflection of cracks in the wafer;

Figure 2a is a schematic view of the optical path in which the direction of the crack extension is parallel to the direction of the line beam;

Figure 2b is a schematic view of the optical path of the direction in which the crack extends and the direction of the line beam are perpendicular;

3 is a schematic structural diagram of a measurement system according to an embodiment of the present invention;

4 is a flow chart of a crack detecting method according to an embodiment of the present invention;

Figure 5 is a schematic view showing the distribution of the reflected light of the line detector when there is no crack;

6a is a schematic view showing a distribution of reflected light when a line beam direction is parallel to a crack extension direction according to an embodiment of the present invention;

6b is a schematic view showing the distribution of reflected light when the direction of the line beam is perpendicular to the direction in which the crack extends.

Detailed ways

In the detailed description of the preferred embodiments that follow, reference is made to the accompanying drawings that form a part of the invention. The accompanying drawings illustrate, by way of example, specific embodiments The exemplary embodiments are not intended to be exhaustive of all embodiments in accordance with the invention. It is to be understood that other embodiments may be utilized and structural or logical modifications may be made without departing from the scope of the invention. Therefore, the following detailed description is not to be considered as limiting

Techniques, methods and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but the techniques, methods and apparatus should be considered as part of the specification, where appropriate.

In the present application, the lens assembly can include any desired beam expander collimating lens, objective lens, tube mirror, beam splitter, and optical lens set with specific functions. The inventors found through research that various defects may occur in the wafer substrate in the semiconductor process, such as cracks, bubbles, and missing corners. These cracks will split, causing the entire chip to fail. Since some defects are often hidden inside the wafer, the inventors proposed to use an infrared source that is transparent to the silicon material for detection, and then analyze the reflected light to determine whether there is a defect inside the wafer. The following is an example of a defect as a crack. .

Figure 1a is a schematic diagram of the reflection of cracks in the wafer, and Figure 1b is a schematic diagram of the reflection of cracks in the wafer.

As shown in FIG. 1a, when there is no crack in the wafer, the incident light beam S1 will be incident from the lower surface of the silicon substrate and will be emitted from the lower surface of the silicon substrate after being reflected in the upper portion of the silicon substrate. Therefore, the incident beam S1 is horizontally symmetrical with the outgoing beam S2. It can be understood whether the generated reflection in the silicon substrate is total reflection, which will depend on the refractive index of the material of the upper portion of the silicon substrate, and even if total reflection does not occur, there is partial light reflection, in other words, even if there is no crack, The intensity of the outgoing beam S2 is also smaller than the incident beam S1.

As shown in FIG. 1b, when there is a crack in the wafer, the incident beam S1 will be incident from the lower surface of the silicon substrate, and then the slit structure (crack) in the wafer will reflect the incident beam S1 and the incident beam S1. Produces occlusion. The slit structure will reflect the incident beam S1 to produce a reflected beam S3. Therefore, the intensity of the outgoing beam S2' from the inside of the silicon substrate in Fig. 1b will be smaller than that of the outgoing beam S2 compared to the outgoing beam S2 in Fig. 1a. Thereby, whether or not there is a crack can be determined by the comparison between the signal that generates the occlusion and the signal that is not blocked by the slit.

As mentioned above, since the infrared surface detector has the disadvantages of slow response and high cost, the use of a surface array infrared detector will result in slowing down the detection speed of the entire system. In addition, although the existence of cracks in theory will affect the distribution of reflected light, in actual detection, due to the roughness of the bottom surface of the silicon wafer and the uneven distribution of the chip on the upper surface, some light will be scattered and re-reflected, etc. When incident illumination, the reflected light shadow signal generated by the crack is easily covered by stray light at other positions of the spot illumination, and the crack signal cannot be detected. Therefore, the inventors propose a technique for detecting a scanning using a line beam illumination and then performing detection using a line array detector.

The inventors found through further research that for wafers, cracks usually exhibit a three-dimensional distribution of length, width, height, and in a plane parallel to the surface of the wafer, cracks generally extend along the direction of the silicon lattice and appear linearly distributed. In other words, the cracks on the wafer plane generally extend in two directions perpendicular to each other.

2a is a schematic view of the optical path parallel to the direction in which the crack extends and the direction in which the line beam extends, and FIG. 2b is a schematic view of the optical path perpendicular to the direction in which the line extends. In an embodiment of the invention, incident light in the form of a line beam will form a line spot on the surface of the object to be tested.

The angular relationship between the direction of crack propagation on the wafer plane and the direction in which the line spot extends is an important factor affecting the detection accuracy: when the direction of the line beam on the wafer plane is parallel to the direction of the crack, a large amount of reflected light is blocked. The beam received by the line detector is S2; when the line beam extends perpendicular to the direction of the crack extension, less light is blocked, and the beam received by the line detector is S2'; when the line beam is incident and When the crack shows an angle of 0 to 90°, the blocked light is between the two cases. It can be seen from the above that when the direction of the line spot extending in the plane is parallel to the longitudinal direction of the crack, the measured value of the line detector for the beam S2 is smaller than the value measured by the line detector for the beam S2', in other words, in Fig. 2a The dark signal is more than that of Figure 2b. In addition, the existence of any small-size cracks in theory affects the distribution of reflected light, but it is easily submerged by the system stray light when the measured signal is weak. Since the crystal lattice has only two mutually perpendicular directions on a plane parallel to the surface of the wafer, the present invention proposes to perform two scanning measurements on the same object to be measured, each measuring the direction of the line spot and the lattice. An axial parallelism ensures maximum signal acquisition in one measurement, extending the smallest size that can be detected.

Based on the foregoing, the present invention proposes a measurement system comprising: an incident light generating unit configured to generate incident light that is transparent to a test object and is a line beam (for example, infrared light transparent to a wafer) a reflected light detecting unit configured to receive the reflected light from the object to be tested and determine a corresponding measurement result; and a processing unit that determines the distribution of the crack in the object to be tested based on the measurement result and the extended feature. The measurement system can also include a carrier unit for carrying the object to be tested. Additionally, the processing unit may be communicatively coupled to the carrier unit and/or the incident light generating unit to adjust the relative angle between the carrier unit and the incident light generating unit to thereby measure the object to be measured in accordance with at least one specified measurement path.

In an embodiment, the specified measurement path may include a first specified measurement path and a second specified measurement path, and the processing unit is configured to determine the first measurement value group by measuring the object to be measured with the first specified measurement path The measurement object is measured by the second specified measurement path, and the second measurement value group is obtained. For different defects and/or objects to be tested, when the incident light is measured according to the first specified measurement path, a first spot is formed on the surface of the object to be tested, and when the incident light is measured according to the second specified measurement path, a second spot is formed on the surface of the object to be tested. And the angle α between the distribution of the first spot on the surface of the object to be tested and the distribution of the second spot on the surface of the object to be tested is greater than 0° and less than 180°. For example, the angle α may be greater than 0° and less than or equal to 90°. When the object to be tested is a wafer, since the axial directions of the crystal lattices are perpendicular to each other, the angle α between the distribution of the first spot on the surface of the object to be tested and the distribution of the second spot on the surface of the object to be tested may be equal to 90. °. After determining the first set of measured values and the second set of measured values, the processing unit determines the distribution of the defect in the object to be tested based on at least the first set of measured values and the second set of measured values, such as defects in the test object. The location, the size of the defect.

Based on the above, please refer to FIG. 3. FIG. 3 is a schematic structural diagram of a measurement system according to an embodiment of the present invention.

The measurement system 100 includes a light source assembly 110, a beam shaping mirror assembly 120, a machine stage 130, a concentrating mirror assembly 140, a line array detection assembly 150, and a processor (not shown), wherein the processor is coupled to at least the machine table 130 and the detection assembly 150. Form a communication connection. In the present embodiment, the light source assembly 110 is an infrared light source, and the emitted light reaches the wafer 200 on the machine table 130 in an obliquely incident manner via the beam shaping mirror group 120. It can be understood that the light source assembly 110 can directly generate a line beam, or shape the emitted light generated by the light source assembly 110 through the beam shaping mirror group 120, thereby forming a line beam whose spot on the surface of the wafer 200 is Line spot.

The wafer 200 will reflect the line beam, and the reflected beam will reach the detection assembly 150 via the concentrating mirror set 140. The processor will analyze the signals received by the detection component 150 to determine the distribution of cracks in the wafer 200, such as the location, size, and direction of the crack in the wafer 200. Line array detection assembly 150 can include at least one line array detector that receives the reflected light in a plane. For example, the line array detection assembly 150 can include a plurality of line detectors arranged in parallel, thereby increasing the range in which the measurement system can be applied.

At the time of detection, the bottom surface of the wafer 200 is placed on the machine table 130 upward, and the wafer chuck 131 of the annular structure of the machine table 130 can prevent the front side of the wafer 200 from being contaminated. The infrared band beam is obliquely incident on the silicon substrate, and a line spot distribution is formed on the bottom surface of the wafer 200. The incident light in the infrared band penetrates into the interior of the silicon substrate and is reflected at the silicon substrate-chip interface. The light collecting mirror group 140 collects the reflected light from the silicon substrate-chip interface. When there is no crack in the wafer 200, the reflected light is collected by the collecting mirror group 140 and all incident on the line array detecting component 150, and the line array is detected. The normal direction of the receiving surface of the assembly 150 is perpendicular to the optical axis direction. When there is a crack in the wafer 200, the partially reflected light will deflect, and the processor can determine whether the crack exists according to the spot integrity received by the line array detecting component 150.

The present invention also proposes a crack detecting method comprising: detecting a subject to be measured by a specified path by incident light; and determining whether the object to be tested includes a defect based on the reflected light generated by the object to be detected based on the incident light. When the incident light is measured according to the first specified path, a first spot is formed on the surface of the object to be tested, and when the incident light is measured according to the second measuring path, a second spot is formed on the surface of the object to be tested, and the first spot is distributed on the surface of the object to be tested. An angle α between the distribution of the second spot on the surface of the object to be tested is greater than 0° and less than 180°. For example, the angle α may be greater than 0° and less than or equal to 90°. When the object to be tested is a wafer, since the axial directions of the crystal lattices are perpendicular to each other, the angle α between the distribution of the first spot on the surface of the wafer and the distribution of the second spot on the surface of the wafer may be equal to 90°. The first measurement value group can be determined by measuring the object to be measured with the first specified path; and the second measurement value group is determined by measuring the object to be measured with the second specified path. As such, the distribution of defects in the test object can be determined based at least on the extended features of the defect in the object to be tested, the first set of measured values, and the second set of measured values.

In order to further illustrate the concept of the present invention, please refer to both FIGS. 3 and 4, wherein FIG. 4 is a flow chart of a crack detecting method according to an embodiment of the present invention, and an exemplary object to be tested is a wafer.

Step S401: determining a distribution of incident light on the surface of the object to be tested based on the distribution feature of the crack.

In this step, the wafer 200 is placed on the machine table 130, and the gap of the wafer is aligned to a specified position to determine the direction of the silicon lattice. Then, the light source assembly 110 is turned on and the stage 130 is rotated such that the gap of the wafer is parallel to the direction in which the line spots on the measurement plane extend. In other words, the distribution of incident light on the surface of the object to be tested is determined based on the direction of the silicon lattice.

Step S402: Perform one-side detection of the wafer by the first measurement path in the first axial direction of the crystal lattice.

Since the crystal lattice has only two mutually perpendicular directions on a plane parallel to the surface of the wafer 200, the incident light is arranged such that the line spot is parallel to the first axial direction of the crystal lattice. Illuminating the line spot to the scanning detection starting point (such as at the center of the wafer) causes the stage 130 to move in a first path (for example, can be designated as a meandering path) to complete the wafer in the first axial direction of the crystal lattice Detection, obtaining the first set of measured values. It can be understood that the first set of measured values can include a moving path of the machine 130 and reflected light data measured by the line detecting component 150 corresponding to the moving path. If a crack exists and extends in the first axial direction of the crystal lattice, the line array detection component 150 will receive a stronger dark signal. Conversely, if the crack propagates in a second axial direction of the crystal lattice that is perpendicular to the first axial direction, the line array detecting component 150 will receive a weaker dark signal.

Step S403: One-side detection of the wafer by the second measurement path in the second axial direction of the crystal lattice.

In this step, the machine table 130 is rotated at 90°, at which time the wafer gap is perpendicular to the direction of the light on the measurement plane, and then the machine 130 is placed in the second path (for example, it can be designated as the same as the first path or Moving differently to complete the detection of the wafer in the second axial direction of the crystal lattice to obtain a second set of measured values. As can be seen from the foregoing, if the crack propagates in the second axial direction of the crystal lattice, the line array detecting component 150 will detect a stronger dark signal.

Step S404: Determine whether there is a crack in the wafer based on the result of the two-sided detection.

As can be seen from the foregoing, the detection in steps S403 and S404 can ensure that the crack is detected in a direction parallel to the direction in which the crack extends, and therefore, based on the result of the above two-sided detection (ie, the first measured value group and The second set of measurements) is able to determine the presence of a crack. In other words, if the two test results indicate that there is no crack, it means that there is no crack at the test position; if at least one of the two test results indicates that there is a crack, it can be determined in the test. A crack present at the location and the direction in which the crack extends.

Specifically, the defects existing in each detection and the corresponding wafer positions can be determined according to the specified trajectory of the machine 130 and the data storage order. By comparing the locations where cracks are detected twice, the repetitive signal is eliminated, giving the distribution of cracks throughout the wafer. In the present embodiment, "repeating the repeated signal" means that when the positions of the cracks referred to in the two detection results are very close, the position of the two cracks which are in close proximity is determined as a crack position in combination with the systematic error.

Although only the case of two measurements is described in detail in this embodiment, those skilled in the art can understand that in other embodiments, it is also possible to perform multiple measurements on the object to be tested. Similarly, if the crack has only one direction of extension in the object to be tested, only the object to be measured is measured in one incident direction.

Based on the measurement system in Fig. 3, the inventors performed simulation analysis using Lightools software. In this simulation, the measurement system parameters are: the source is a wavelength of 1550 nm, the line spot size is 17*0.08 mm; the collection lens set 140 has a numerical aperture of 0.25, and the full field of view is 3.4 mm, 5 times magnification. The wafer parameters to be tested are: wafer thickness 750 microns, crack size 2*10*100 (height) micron, located at the bottom of the wafer, showing a crack distribution.

FIG. 5 is a schematic diagram showing the distribution of planar reflected light of the line detector receiving surface when there is no crack in the wafer. At this time, the reflected light exhibits a nearly uniform linear distribution, and there are some stray light below the line spot due to surface scattering and the like, that is, a portion having a slightly lighter color.

6a is a schematic view showing a distribution of reflected light when a line spot extending direction is parallel to a crack extending direction according to an embodiment of the present invention; and FIG. 6b is a reflected light distribution when a line spot extending direction is perpendicular to a crack extending direction according to an embodiment of the present invention; schematic diagram.

As can be seen from the foregoing, when there is a crack in the wafer, the crack will reflect the incident light, thereby reducing the intensity of the emitted light. When the direction of the line spread is parallel to the extension of the crack, the contrast of the dark signal is much stronger than when the incident light of the same crack is perpendicular to the longitudinal direction of the crack. This is because when the incident direction of the incident light is perpendicular to the longitudinal direction of the crack, the crack can Reflect more incident light.

As shown in Figure 6a, there is a distinct dark signal in the spot (the central black portion), while for the spot in Figure 6b, the dark signal is relatively weak. Thereby, the position of the crack in the wafer can be determined. The number of cracks can also be determined by multiple measurements.

In actual measurement, factors such as the refractive index and structural distribution of the material on the wafer cause small changes in the angle of reflection.

It can be understood that the solution can also be applied to the detection of other cracks, and different light sources are set according to the material to be tested, and the wavelength of the light source (for example, ultraviolet, visible, infrared, etc.) is changed to realize detection. In addition, although the above embodiment is explained by using a crack as a detection object, those skilled in the art can understand that the measurement system and the measurement method proposed by the present invention are also applicable to other types of defects, such as the inside of the object to be tested. Bubbles, missing corners of the object to be tested, and so on. At this time, the detection method is similar to the crack detection, that is, the presence of the bubble changes the reflected light path of the part of the incident light, thereby causing the received reflected signal to be shadowed, which is detected by the measurement system to determine the presence of the bubble.

The invention adopts an optical method to measure, and is a non-contact non-destructive and pollution-free measuring method, and the measuring speed is very fast, and can be used for process monitoring in a production process. In addition, since the present invention uses reflected light as the signal light, the pattern distribution on the wafer has little effect on the detection result, and the wafer defect in any type and any process can be measured; compared with the reflected light imaging measurement method, the present invention The measurement system has a simple structure, fast detection speed, low cost, and less stray light, and has higher detection sensitivity.

Accordingly, the present invention has been described with reference to the specific examples thereof, which are intended to be illustrative only and not restrictive of the invention, but it will be apparent to those skilled in the art Variations, additions or deletions of the disclosed embodiments may be made on the basis of the spirit and scope of the invention.

Claims

An optical measurement system, comprising:

An incident light generating unit configured to generate incident light for measuring an object to be tested;

a reflected light detecting unit configured to receive reflected light from the object to be tested and determine a corresponding measurement result;

Processing the unit and configured to measure the object to be tested by using a spot formed on the surface of the object to be measured by the incident light, the processing unit determining the defect based on the measurement result Distribution in the test object.
The measurement system of claim 1 further comprising a carrier unit configured to carry the object to be tested.
The measurement system of claim 1 wherein said incident light is a line beam.
The measurement system of claim 1 wherein said incident light is transparent relative to said object to be tested.
The measurement system of claim 2 wherein said processing unit is communicatively coupled to said carrier unit and/or said incident light generating unit to adjust between said carrier unit and said incident light generating unit The relative angle of the measurement so that the object is measured in accordance with at least one specified measurement path.
The measurement system of claim 1 wherein said reflected light detecting unit comprises at least one line array detector for receiving said reflected light.
The measurement system of claim 5 wherein said specified measurement path comprises a first designated measurement path and a second specified measurement path, and wherein said processing unit is configured to pass said first specified measurement path pair The object to be tested is measured to determine a first set of measured values; and the object to be tested is measured by the second specified measuring path, thereby obtaining a second set of measured values.
The measuring system according to claim 7, wherein the incident light forms a first spot on the surface of the object to be tested when measured according to the first specified measuring path, and the incident light is in accordance with the second designation. Measuring a path between the second spot formed on the surface of the object to be tested, the distribution of the first spot on the surface of the object to be tested and the distribution of the second spot on the surface of the object to be tested The angle α is greater than 0° and less than 180°.
The measurement system of claim 8 wherein said angle α is greater than 0° and less than or equal to 90°.
The measurement system of claim 7 wherein:

The processing unit is configured to determine a distribution of the defect in the object to be tested based on at least the first set of measured values and the second set of measured values.
The measurement system according to claim 10, wherein the distribution of the defect in the object to be tested comprises: a position of the defect in the object to be tested, and a size of the defect.
The measurement system according to any one of claims 1 to 11, wherein the direction in which the spot extends is parallel to the direction in which the defect extends.
An optical measuring method, comprising:

Detecting the object to be tested with the specified path by incident light;

Determining whether the object to be tested includes a defect according to the reflected light generated by the object to be tested based on the incident light.
The measuring method according to claim 13, wherein the incident light is a line beam.
The measuring method according to claim 13, wherein the incident light is transparent with respect to the object to be tested.
The measuring method according to claim 13, wherein said specified path comprises a first designated path and a second designated path.
The measuring method according to claim 16, wherein the incident light forms a first spot on the surface of the object to be tested when measured according to the first specified path, and the incident light is measured according to the second specified path. Forming a second spot on the surface of the object to be measured, an angle α between a distribution of the first spot on the surface of the object to be tested and a distribution of the second spot on the surface of the object to be tested is greater than 0° and less than 180 °.
The measuring method according to claim 17, wherein the angle α is greater than 0° and less than or equal to 90°.
The measuring method according to claim 16, wherein the object to be tested is measured by the first specified path, thereby determining a first set of measured values; and the second measured path is used for the measuring The object is measured to determine a second set of measured values.
The measuring method according to claim 19, wherein said defect is determined based on at least an extension characteristic of said defect in said object to be tested, said first set of measured values, and said second set of measured values Distribution in the test object.
The measuring method according to any one of claims 13 to 20, wherein an extending direction of the spot formed by the incident light on the surface of the object to be tested is parallel to an extension of the defect in the object to be tested. direction.