Grinding disc, chemical mechanical polishing equipment and detection method

Abstract

The invention provides a grinding disc, chemical mechanical polishing equipment and a detection method.The grinding disc comprises at least one finishing area and at least one scratch detection area which are arranged at the grinding end of the grinding disc, the finishing area is used for grinding a wafer, and the scratch detection area comprises a scratch detection material; whether the wafer has a scratch risk or not is judged by detecting whether the scratch detection material is scraped on the grinding pad by the hard particles or not in the wafer grinding process. In the wafer grinding process, if particles with relatively high hardness are generated on the grinding pad, when the particles with relatively high hardness are cleaned by the grinding disc, the scratch detection area is scratched by the particles with relatively high hardness, the scratch detection material is scratched on the surface of the grinding pad, and when the scratched scratch detection material is detected on the grinding pad, an alarm is triggered. Therefore, the wafer scratch can be timely and effectively detected in the wafer grinding process, the subsequent wafer is prevented from being continuously scratched by particles with relatively high hardness, and the yield of the wafer is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a grinding disc, chemical mechanical polishing equipment and a detection method. Background Art

[0002] The semiconductor industry is a high-precision industry that places extremely high demands on wafer processing equipment. With the development of the semiconductor industry, the feature size of integrated circuits continues to shrink, so the flatness quality of the wafer surface is becoming more and more stringent, and the stability requirements for chemical mechanical polishing equipment are also becoming higher and higher.

[0003] Chemical Mechanical Polishing (CMP) is an important means to achieve wafer surface flatness. During the grinding process, the grinding liquid will flow on the grinding pad. The grinding disc is needed to adjust the flow field of the grinding liquid to make the grinding particles evenly distributed. The grinding disc is also needed to clean the derivatives and agglomerated particles in the grinding process. In this process, particles with higher hardness may cause defects such as wafer scratches. Among them, particles with higher hardness may be agglomerated grinding particles in the grinding liquid, debris from the grinding pad, diamonds from the grinding disc, metal or solder debris, hard particles grown by the previous chemical vapor deposition (CVD) or aluminum oxide dropped from the machine.

[0004] In the prior art, if a wafer is found to be scratched when scanning for defects, the usual practice is to shut down the machine immediately, clean the machine, and replace the grinding pad and grinding disc to prevent subsequent wafers from being scratched. However, this detection method may not be timely. If scratches are not found in time when scanning for defects, subsequent wafers may continue to be scratched in the machine. Therefore, it is very important for chemical mechanical polishing equipment to detect wafer scratches in time to stabilize product quality.

[0005] Therefore, it is necessary to provide a grinding disc, a chemical mechanical polishing device and a detection method to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a grinding disc, a chemical mechanical polishing device and a detection method, so as to improve the existing problem that wafer scratches cannot be detected in time during the wafer grinding process.

[0007] In a first aspect, the present invention provides a grinding disc, comprising: at least one trimming area and at least one scratch detection area arranged at the grinding end of the grinding disc, the trimming area being used for grinding wafers, the scratch detection area comprising scratch detection material, and determining whether there is a risk of scratching the wafer by detecting whether the scratch detection material is scraped onto the grinding pad by hard particles during the wafer grinding process.

[0008] In a possible embodiment, the scratch detection material is a fluorescent material or a highly visible material. The beneficial effect is that the fluorescent material and the highly visible material have strong recognizability, so as to be easily identified and detected.

[0009] In a possible embodiment, the trimming area is arranged around the scratch detection area; or, the scratch detection area is arranged around the trimming area; or, the scratch detection area is located in the middle and the trimming area is located on both sides of the scratch detection area; or, the trimming area is located in the middle and the scratch detection area is located on both sides of the trimming area; or, the trimming area and the scratch detection area are nested in multiple layers, and one of two adjacent layer areas is the trimming area and the other is the scratch detection area.

[0010] In a possible embodiment, a plurality of diamonds are arranged at intervals in the trimming area, the bottom surface of the scratch detection area is lower than the bottom end of the diamond, and the height difference between the bottom surface of the scratch detection area and the bottom end of the diamond is 10 to 100 microns. The beneficial effect is that even if the length of the diamond is constantly worn during its life cycle, the bottom surface of the scratch detection area is always set to be lower than the bottom end of the diamond by a certain distance, thereby avoiding excessive friction caused by excessive pressure between the bottom surface of the scratch detection area and the grinding pad, and then avoiding the scratch detection material from falling off, so as to avoid misjudgment.

[0011] In a possible embodiment, the thickness of the scratch detection area is 1 micron to 1 millimeter. The beneficial effect is that by reasonably setting the thickness of the scratch detection area, on the one hand, the internal stress distribution of the grinding disc when it is under pressure can be uniform, and on the other hand, it can be avoided that the scratch detection area is too thin, resulting in too little scratch detection material falling off when high hardness particles contact and scratch the scratch detection area, and cannot be captured by the detection device.

[0012] In a second aspect, the present invention further provides a chemical mechanical polishing device, which includes: a grinding head, a grinding pad, a detection device and a grinding disc as described in any of the above embodiments, wherein the detection device is used to detect the scratch detection material scraped onto the grinding pad.

[0013] In a possible embodiment, the scratch detection material is a fluorescent material, and the chemical mechanical polishing device further comprises a detection light source arranged corresponding to the polishing pad, and under the irradiation of the detection light source, the fluorescent material falling on the polishing pad emits fluorescence. The beneficial effect is that the polishing pad is irradiated by the detection light source emitting light of a specific wavelength, so that the fluorescent material scratched on the polishing pad emits fluorescence, so as to be easily identified and detected.

[0014] In a possible embodiment, the detection device includes a camera arranged corresponding to the grinding pad and an image recognition module connected to the camera, wherein the camera is used to collect the grinding pad image in real time during the wafer grinding process, and the image recognition module is used to identify whether the grinding pad image contains the scratch detection material. The beneficial effect is that the grinding pad image is collected in real time during the wafer grinding process by the camera, so as to facilitate observation of whether there is any scratch detection material scraped off the grinding pad. The image recognition module performs real-time image processing on the collected grinding pad image, and timely identifies whether the grinding pad image contains the scratch detection material, thereby realizing automatic and intelligent detection and improving detection efficiency.

[0015] In a possible embodiment, the chemical mechanical polishing equipment further includes an alarm device connected to the detection device, and during the wafer grinding process, when the detection device detects that the scratch detection material is on the grinding pad, the detection device triggers the alarm device to sound an alarm. The beneficial effect is that the alarm device is linked to the detection device, and when the detection device detects that the scratch detection material is on the grinding pad, the alarm device is immediately triggered to sound an alarm, thereby promptly reminding the operator.

[0016] In a possible embodiment, the alarm device includes an alarm light and / or an alarm speaker. The beneficial effect is that the operator is effectively reminded by the alarm light and / or the alarm speaker.

[0017] In a third aspect, the present invention further provides a detection method, which comprises the following steps:

[0018] During the wafer grinding process, the wafer is ground using a grinding disc as described in any of the above embodiments to detect whether the scratch detection material is scraped onto the grinding pad by hard particles, so as to determine whether there is a risk of scratching the wafer.

[0019] The beneficial effect of the grinding disc provided by the present invention is that during the wafer grinding process, if particles with higher hardness are generated on the grinding pad, when the grinding disc cleans the particles with higher hardness, the scratch detection area will be scratched by the particles with higher hardness, and the scratch detection material will be scraped onto the surface of the grinding pad, so as to timely and effectively detect wafer scratches during the wafer grinding process, thereby preventing subsequent wafers from being scratched by particles with higher hardness, thereby improving the wafer yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a bottom view of the grinding disc of the present invention.

[0021] Figure 2 It is a longitudinal cross-sectional view of the grinding disc of the present invention.

[0022] Figure 3 It is a schematic diagram of the chemical mechanical polishing equipment of the present invention.

[0023] Explanation of symbols: grinding disc 100; dressing area 110; diamond 111; fixing layer 112; scratch detection area 120;

[0024] Polishing head 200; polishing pad 300. DETAILED DESCRIPTION

[0025] Chemical Mechanical Polishing (CMP) technology is a technology that combines chemical and mechanical actions. First, the wafer surface material reacts chemically with the oxidant, catalyst, etc. in the grinding liquid to form a soft layer that is relatively easy to remove. Then, the abrasive in the grinding liquid and the polishing pad mechanically remove the soft layer to expose the wafer surface again. Then, a chemical reaction is carried out again, thereby completing the wafer surface polishing in the alternating chemical and mechanical processes.

[0026] In the prior art, during the wafer grinding process, some particles with higher hardness are generated. For example, the grinding particles in the grinding liquid sometimes aggregate into larger particles, the grinding pad may retain debris of a certain hardness during use, diamond, metal or solder debris on the grinding disc, hard particles grown by the previous chemical vapor deposition (CVD) or aluminum oxide dropped from the machine, etc. The scratch defects caused by these particles with higher hardness will not only leave pits on the wafer surface, but also may scratch the wafer surface pattern, thereby affecting the wafer yield.

[0027] In view of the problems existing in the above-mentioned technologies, an embodiment of the present invention provides a grinding disc 100. Figure 1 is a bottom view of the grinding disc of the present invention, see Figure 1The grinding disc 100 includes: at least one trimming area 110 and at least one scratch detection area 120 arranged at the grinding end of the grinding disc 100, the trimming area 110 is used to grind the wafer, and the scratch detection area 120 includes a scratch detection material. By detecting whether the scratch detection material is scraped onto the grinding pad 300 by hard particles during the wafer grinding process, it is determined whether the wafer has a scratch risk.

[0028] It can be understood that when the scratch detection material is detected on the polishing pad 300 , it is considered that the wafer has a greater possibility of being scratched, otherwise, the wafer has a smaller possibility of being scratched.

[0029] In a preferred embodiment, the scratch detection material is a fluorescent material or a high-visibility material. The fluorescent material has a fluorescent property. When illuminated by a specific light source, the fluorescent material will emit a specific color of fluorescence for easy identification and detection. The high-visibility material, for example, a high-visibility coating such as red, has a distinct color difference from the polishing pad, which is easy to distinguish and identify.

[0030] In a specific embodiment, the trimming area 110 is arranged around the scratch detection area 120, see Figure 1 The scratch detection area 120 is located at the center of the grinding end of the grinding disc 100 . The scratch detection area 120 can be circular or square in shape. The trimming area 110 is annular and is arranged along a circle around the scratch detection area 120 .

[0031] In a specific embodiment, the scratch detection area 120 is arranged around the trimming area 110. For example, the scratch detection area 120 is arranged along the edge of the grinding end of the grinding disc 100. The trimming area 110 is located inside the scratch detection area 120. The trimming area 110 can be circular or square, etc., and the scratch detection area 120 is ring-shaped.

[0032] In some specific embodiments, the grinding end of the grinding disc 100 is divided into three surrounding parts, the scratch detection area 120 is located in the middle, and the trimming area 110 is located on both sides of the scratch detection area 120; or, the trimming area 110 is located in the middle, and the scratch detection area 120 is located on both sides of the trimming area 110.

[0033] In a specific embodiment, the trimming area 110 and the scratch detection area 120 are arranged in a multi-layer nested manner, and one of the two adjacent layers is the trimming area 110, and the other is the scratch detection area 120. For example, the grinding end of the grinding disc 100 is divided into three parts, which are the trimming area 110 located in the center, the scratch detection area 120, and the trimming area 110 located on the outside from the inside to the outside.

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0035] In this embodiment, see Figure 3 During the wafer grinding process, the ordinary grinding particles on the grinding pad 300 will not scrape off the fluorescent material or the highly visible material. However, when the high-hardness particles on the grinding pad 300 rub against the fluorescent material or the highly visible material, they will scrape and peel off the fluorescent material or the highly visible material, causing the fluorescent material or the highly visible material to fall on the grinding pad 300. Figure 3 The circular areas on the grinding pad 300 are the scraped fluorescent materials or high-visibility materials. Since the fluorescent material emits fluorescence of a specific color and brightness under the irradiation of a specific light source, the fluorescent material with fluorescence has a significant color difference with the grinding pad 300 visually, and the high-visibility material has a strong visibility and also has a significant color difference with the grinding pad 300 visually. The fluorescent material and the high-visibility material are easy to identify and detect. When the scraped fluorescent material or high-visibility material is detected on the grinding pad 300, it means that there are high-hardness particles on the grinding pad 300, and the wafer will also be scratched by the high-hardness particles. In the prior art, regular replacement of the grinding pad 300 cannot timely avoid high-hardness particles from scratching the wafer. In the present invention, once the fluorescent material or high-visibility material is found on the grinding pad 300, the operator needs to check and clean the machine, replace the new grinding pad 300 and the grinding disc 100 to avoid subsequent wafers from being scratched by particles with higher hardness, thereby greatly reducing the scratches on the wafer.

[0036] In a preferred embodiment, Figure 2 is a longitudinal sectional view of the grinding disc of the present invention, see Figure 2, a plurality of diamonds 111 are arranged at intervals in the trimming area 110, and the bottom surface of the scratch detection area 120 is lower than the bottom end of the diamond 111, that is, the bottom end of the diamond 111 protrudes out of the bottom surface of the scratch detection area 120, and the height difference between the bottom surface of the scratch detection area 120 and the bottom end of the diamond 111 is 10 to 100 microns. In this embodiment, even if the length of the diamond 111 is constantly worn during its life cycle, the bottom surface of the scratch detection area 120 is always lower than the position of the bottom end of the diamond 111, thereby avoiding excessive friction caused by excessive pressure between the scratch detection area 120 and the polishing pad 300, and then avoiding partial shedding of the scratch detection material, so as to avoid misjudgment.

[0037] In a preferred embodiment, see Figure 2 , the thickness of the scratch detection area 120 is 1 micron to 1 millimeter. In this embodiment, by reasonably setting the thickness of the scratch detection area 120, the accuracy and comprehensiveness of the scratch detection in the scratch detection area 120 can be ensured. On the one hand, it avoids the uneven distribution of internal stress of the grinding disc 100 when it is under pressure due to the scratch detection area 120 being too thick. On the other hand, it avoids the scratch detection area 120 being too thin, which leads to too little scratch detection material falling off when the high hardness particles contact the scratch detection area 120 and produce scratches, and cannot be captured by the detection device.

[0038] In a specific embodiment, see Figure 2 , the bottom surface of the scratch detection area 120 is a plane.

[0039] In a specific embodiment, see Figure 2 The trimming area 110 includes a fixed layer 112 disposed at the grinding end of the grinding disc 100 , and a plurality of diamonds 111 are embedded and fixed in the fixed layer 112 at intervals, and a portion of the diamonds 111 extends out of the bottom surface of the fixed layer 112 .

[0040] In addition, an embodiment of the present invention further provides a chemical mechanical polishing device, see Figure 3 The chemical mechanical polishing equipment includes: a grinding head 200, a grinding pad 300, a detection device and a grinding disc 100 as in any of the above embodiments, and the detection device is used to detect the scratch detection material scraped on the grinding pad 300.

[0041] In this embodiment, a detection device is provided for the grinding pad 300 in the chemical mechanical polishing equipment to detect the scratch detection material, i.e., the fluorescent material or the highly visible material, scraped onto the grinding pad 300. It does not rely on manual observation, and the detection device is used to realize automated detection, thereby improving the detection efficiency and providing timely alarm reminders.

[0042] In a specific embodiment, the scratch detection material is a fluorescent material, and the chemical mechanical polishing device further includes a detection light source arranged corresponding to the polishing pad 300. Under the irradiation of the detection light source, the fluorescent material falling on the polishing pad 300 emits fluorescence. In this embodiment, the detection light source is used to emit light of a specific wavelength and irradiate the polishing pad 300, so that the fluorescent material scraped on the polishing pad 300 emits fluorescence. There is a significant color difference between the fluorescent material with fluorescence and the polishing pad 300. Even if a small fluorescent material is scraped off, it is easy to be detected by the detection device, so that an alarm is issued in time to remind the operator.

[0043] Preferably, the detection light source can be a light source with higher energy such as an ultraviolet light source, a blue light source, etc.

[0044] In a specific embodiment, the detection device includes a camera arranged corresponding to the polishing pad 300, and the camera is used to collect images of the polishing pad 300 in real time during the wafer polishing process. In this embodiment, during the wafer polishing process, the camera is used to collect images of the polishing pad 300 in real time to facilitate observation of whether there is any fluorescent material or highly visible material scraped off the polishing pad 300.

[0045] In a preferred embodiment, the detection device further includes an image recognition module connected to the camera, and the image recognition module is used to identify whether the image of the polishing pad 300 contains fluorescent materials or highly visible materials. In this embodiment, the image recognition module is used to perform image recognition processing on the collected image of the polishing pad 300 to detect and identify whether the image of the polishing pad 300 contains fluorescent materials or highly visible materials. If fluorescent materials or highly visible materials are contained, an alarm is triggered. By designing a detection method based on image recognition technology, automatic and intelligent scratch detection is achieved, and detection efficiency is improved.

[0046] In a preferred embodiment, the chemical mechanical polishing equipment further includes an alarm device connected to the detection device. During the wafer grinding process, when the detection device detects that there is a fluorescent material or a highly visible material on the grinding pad 300, the detection device triggers the alarm device to sound an alarm. In this embodiment, once the detection device detects that there is a fluorescent material or a highly visible material on the grinding pad 300, the alarm device will be immediately triggered to sound an alarm, so as to promptly and effectively remind the operator to take timely measures to prevent subsequent wafers from being affected. The present invention provides effective monitoring during the grinding process of the chemical mechanical polishing process by detecting the scratch condition of the wafer in real time during the wafer grinding process and promptly reminding through an alarm.

[0047] In some specific embodiments, the alarm device includes an alarm lamp and / or an alarm speaker. In this embodiment, a flashing alarm light is emitted by the alarm lamp, and an alarm sound is emitted by the alarm speaker to achieve a double warning effect.

[0048] The chemical mechanical polishing equipment of the present invention provides a technical solution for real-time detection of wafer scratches during wafer grinding. The scratch detection area 120 is set on the grinding disc 100, and the real-time acquisition of the grinding pad 300 image by the camera is used. The image recognition technology is used to automatically identify whether the grinding pad 300 image contains fluorescent materials or highly visible materials, which is not affected by the subjective influence of manual judgment, thereby ensuring the reliability and accuracy of the detection. Once the fluorescent material or highly visible material is scraped on the grinding pad 300, the image recognition module can quickly identify it and trigger the alarm device to send out an alarm. The automated alarm and response mechanism can quickly remind the operator once a scratch is found to avoid scratching subsequent wafers.

[0049] An embodiment of the present invention further provides a detection method, which comprises the following steps:

[0050] During the wafer grinding process, the wafer is ground using a grinding disc 100 as in any of the above embodiments to detect whether the scratch detection material is scraped onto the grinding pad 300 by hard particles, so as to determine whether there is a risk of scratching the wafer.

[0051] In a preferred embodiment, detecting whether the scratch detection material is scraped onto the polishing pad 300 by hard particles to determine whether the wafer has a scratch risk includes:

[0052] A detection device and an alarm device are provided. The detection device is used to detect the polishing pad 300. If the detection device detects scratch detection material on the polishing pad 300, it is determined that the wafer has a scratch risk, and the detection device triggers the alarm device to sound an alarm.

[0053] In a specific embodiment, the detection device includes a camera arranged corresponding to the polishing pad 300 and an image recognition module connected to the camera.

[0054] The polishing pad 300 is detected by using a detection device. If the detection device detects that the polishing pad 300 has scratched the detection material, it is determined that there is a risk of scratching the wafer, and the detection device triggers the alarm device to sound an alarm, including:

[0055] During the wafer grinding process, the camera collects the image of the grinding pad 300 in real time, and the image recognition module identifies whether the image of the grinding pad 300 contains scratch detection material. If it contains scratch detection material, it is determined that the wafer is at risk of scratching, and the image recognition module triggers the alarm device to sound an alarm.

[0056] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes are within the scope and spirit of the present invention in the claims. The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the various technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above-mentioned embodiments only express several embodiments of the present invention, and their descriptions are more specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

[0057] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A grinding disc, characterized in that: include: at least one finishing area and at least one scratch detection area disposed at the grinding end of the grinding disc; The trimming area is used for grinding wafers; The scratch detection area includes a scratch detection material. Whether the scratch detection material is scraped onto the grinding pad by hard particles during the wafer grinding process is detected to determine whether the wafer has a scratch risk.

2. The grinding disc according to claim 1, characterized in that: The scratch detection material is a fluorescent material or a highly visible material.

3. The grinding disc according to claim 1 or 2, characterized in that: The trimming area is arranged around the scratch detection area; Alternatively, the scratch detection area is arranged around the trimming area; Alternatively, the scratch detection area is located in the middle, and the trimming areas are located on both sides of the scratch detection area; Alternatively, the trimming area is located in the middle, and the scratch detection area is located on both sides of the trimming area; Alternatively, the trimming area and the scratch detection area are nested in multiple layers, and one of two adjacent layers is the trimming area, and the other is the scratch detection area.

4. The grinding disc according to claim 1 or 2, characterized in that: A plurality of diamonds are arranged at intervals in the trimming area; The bottom surface of the scratch detection area is lower than the bottom end of the diamond, and the height difference between the bottom surface of the scratch detection area and the bottom end of the diamond is 10 to 100 microns.

5. The grinding disc according to claim 1 or 2, characterized in that: The thickness of the scratch detection area is 1 micrometer to 1 millimeter.

6. A chemical mechanical polishing device, characterized in that: include: A grinding head, a grinding pad, a detection device, and a grinding disc as claimed in any one of claims 1 to 5; The detection device is used to detect the scratch detection material scraped onto the grinding pad.

7. The chemical mechanical polishing equipment according to claim 6, characterized in that: The scratch detection material is a fluorescent material; The chemical mechanical polishing equipment further comprises a detection light source arranged corresponding to the polishing pad, and under the irradiation of the detection light source, the fluorescent material falling on the polishing pad emits fluorescence.

8. The chemical mechanical polishing equipment according to claim 6, characterized in that: The detection device includes a camera arranged corresponding to the polishing pad and an image recognition module connected to the camera; The camera is used to collect the grinding pad image in real time during the wafer grinding process. The image recognition module is used to recognize whether the polishing pad image contains the scratch detection material.

9. The chemical mechanical polishing equipment according to claim 6, characterized in that: It also includes an alarm device connected to the detection device. During the wafer grinding process, when the detection device detects that the scratch detection material is on the grinding pad, the detection device triggers the alarm device to sound an alarm.

10. A detection method, characterized in that: The steps include: During the wafer grinding process, the wafer is ground using the grinding disc as described in any one of claims 1 to 5, and it is detected whether the scratch detection material is scraped onto the grinding pad by hard particles to determine whether there is a risk of scratching the wafer.

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