Wafer carrier position detection apparatus and method, polishing apparatus

Abstract

This disclosure provides a wafer carrier position detection device and method, and a polishing apparatus. The device includes: a plurality of positioning points, which are spaced apart and circumferentially distributed around a target placement area to position the edge of the wafer carrier, wherein at least one positioning point is a laser positioning point; a laser sensor, which is disposed above a polishing pad, emits laser light towards the laser positioning point, and receives reflected laser signals returned from the laser positioning point; and a processor, which is communicatively connected to the laser sensor, for comparing the reflected laser signals with a preset laser signal to determine whether the wafer carrier is in the target position. The wafer carrier position detection device and method and polishing apparatus provided in this disclosure improve the product glazing phenomenon by accurately positioning the wafer carrier and avoiding weak cleaning areas caused by the wafer carrier blocking the high-pressure cleaning water column.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing technology, and in particular to a wafer carrier position detection device and method, and polishing equipment. Background Technology

[0002] During double-sided polishing, due to the inherent instability of the chemical mechanical polishing process, the silicates generated by the reaction between the polished wafer and the alkaline polishing solution are prone to accumulate in the solution. If the cleaning ability after polishing is insufficient, the reaction products are very likely to saturate and precipitate in the polishing pad, polishing solution pipelines, and storage tank, producing white or yellowish-brown precipitates, i.e., the equipment becomes glazed.

[0003] The presence of these precipitates can cause inconvenience for routine equipment maintenance and cleaning, or, more seriously, probabilistically detach and accumulate on the polishing pad surface during material circulation. As the wafer carrier moves, these accumulations periodically form a glaze layer, resulting in uneven surface roughness distribution on the polishing pad. This glaze layer repeatedly grinds the product, leading to product defects, primarily microscopic particle contamination or microscopic scratches. The presence of the glaze layer on the polishing pad surface causes ring marks or yellowing on the polished product surface, a phenomenon known as glazing. Glazing of polished products can be further categorized into ring-shaped glazing, banded glazing, and composite glazing.

[0004] One reason for the formation of ring-shaped glaze is that the wafer carrier is misaligned during placement due to human factors, causing the wafer carrier to physically block the cleaning water column, thus creating a glaze layer.

[0005] In related technologies, the method to solve the problem of ring-shaped glazing in products is to trim the surface of the polishing pad to remove the glaze layer and restore the surface roughness of the polishing pad. However, as the surface of the polishing pad continues to wear down, fixed trimming conditions can no longer guarantee that the polishing pad will maintain a stable removal rate throughout its lifespan. Replacing the polishing pad with a new one will increase costs. Summary of the Invention

[0006] This disclosure provides a wafer carrier position detection device and method, and a polishing equipment. By accurately positioning the wafer carrier, it avoids weak cleaning areas caused by the wafer carrier blocking the high-pressure cleaning water column, thereby improving the glazing phenomenon of the product.

[0007] The technical solutions provided in this disclosure are as follows:

[0008] According to a first aspect of this disclosure, a wafer carrier position detection device is provided for use in a polishing apparatus, the polishing apparatus including a polishing pad having multiple placement areas, the wafer carrier position detection device being used to place the wafer carrier at a target position within a target placement area; the wafer carrier position detection device includes:

[0009] A plurality of positioning points are spaced apart and distributed circumferentially around the target placement area to position the edge of the wafer carrier, wherein at least one of the positioning points is a laser positioning point;

[0010] A laser sensor, disposed above the polishing pad, emits a laser beam toward the laser positioning point and receives the reflected laser signal returning from the laser positioning point; and

[0011] The processor is communicatively connected to the laser sensor and is used to compare the reflected laser signal with a preset laser signal to determine whether the wafer carrier is at the target position.

[0012] For example, there are three positioning points, one of which is the laser positioning point, and the other two are fixed marker points.

[0013] For example, the polishing pad is provided with an inner pin ring and an outer pin ring, the placement area is located in the space between the inner pin ring and the outer pin ring, and one of the two fixed marking points is located at the position corresponding to the tangent point between the target placement area and the inner pin ring, and the other is located at the position corresponding to the tangent point between the target placement area and the outer pin ring. The laser positioning point is located on the edge of the target placement area near the other placement area.

[0014] For example, the wafer carrier includes a carrier body and teeth disposed around the periphery of the carrier body, with gaps formed between adjacent teeth, and the gaps exposing a portion of the surface of the polishing pad. The surface reflectivities of the carrier body, the teeth, and the polishing pad are different. The preset laser signal includes at least whether the wafer carrier is at the target position, and the light intensity value of the laser reflected back by the surface of one of the gaps or the teeth. The processor is specifically used to compare the light intensity value of the reflected laser signal with the light intensity value of the preset laser signal to determine whether the wafer carrier is at the target position.

[0015] For example, the surface reflectivity of the polishing pad is less than that of the carrier body and the teeth; wherein, the preset laser signal includes whether the wafer carrier is at the target position, and a first light intensity value of the laser reflected back by the tooth gap surface; the processor is specifically used for:

[0016] When the intensity value of the reflected laser signal is equal to the first intensity value, it is determined that the wafer carrier is currently at the target position;

[0017] When the intensity of the reflected laser signal is greater than the first intensity value, it is determined that the wafer carrier is not currently at the target position.

[0018] For example, the preset laser signal also includes a second light intensity value of the laser reflected back by the surface of the tooth; the processor is further configured to compare the light intensity value of the reflected laser signal with the second light intensity value to determine the current offset state of the wafer carrier.

[0019] For example, the step of comparing the light intensity value of the reflected laser signal with the second light intensity value to determine the current offset state of the wafer carrier specifically includes:

[0020] When the light intensity value of the reflected laser signal is equal to the second light intensity value, it is determined that the current offset state of the wafer carrier is that it is deviating from the target position in the circumferential direction of the wafer carrier;

[0021] When the intensity value of the reflected laser signal is greater than the second intensity value, it is determined that the current offset state of the wafer carrier is that it is deviating from the target position in the radial direction of the wafer carrier, and the deviation direction is towards the center of the placement area.

[0022] According to a second aspect of this disclosure, a polishing apparatus is provided, including a wafer carrier position detection device as described above.

[0023] According to a third aspect of this disclosure, a wafer carrier position detection method is provided, which uses the wafer carrier position detection device as described above to place the wafer carrier at a target position in a target placement area of ​​a polishing pad; the method includes the following steps:

[0024] When placing the wafer carrier, the edges of the wafer carrier are positioned using a plurality of positioning points, wherein...

[0025] For the laser positioning point, the laser sensor emits a laser towards the laser positioning point and receives the reflected laser signal returned from the laser positioning point;

[0026] Based on the reflected laser signal and the preset laser signal, it is determined whether the wafer carrier is at the target position.

[0027] For example, the preset laser signal includes whether the wafer carrier is at the target position and a first light intensity value of the laser reflected back by the tooth gap surface;

[0028] The step of determining whether the wafer carrier is at the target position based on the reflected laser signal and the preset laser signal specifically includes:

[0029] When the intensity value of the reflected laser signal is equal to the first intensity value, it is determined that the wafer carrier is currently at the target position;

[0030] When the intensity of the reflected laser signal is greater than the first intensity value, it is determined that the wafer carrier is not currently at the target position.

[0031] For example, the preset laser signal also includes a second light intensity value of the laser reflected back by the surface of the tooth;

[0032] The step of determining whether the wafer carrier is at the target position based on the reflected laser signal and the preset laser signal specifically includes:

[0033] The intensity value of the reflected laser signal is compared with the second intensity value to determine the current offset state of the wafer carrier.

[0034] For example, comparing the intensity value of the reflected laser signal with the second intensity value to determine the current offset state of the wafer carrier specifically includes:

[0035] When the light intensity value of the reflected laser signal is equal to the second light intensity value, it is determined that the current offset state of the wafer carrier is that it is deviating from the target position in the circumferential direction of the wafer carrier;

[0036] When the intensity value of the reflected laser signal is greater than the second intensity value, it is determined that the current offset state of the wafer carrier is that it is deviating from the target position in the radial direction of the wafer carrier, and the deviation direction is towards the center of the placement area.

[0037] The beneficial effects of the embodiments disclosed herein are as follows:

[0038] In the above solution, by setting the laser sensor, when the wafer carrier is placed in the target placement area of ​​the polishing pad, the laser sensor can emit a laser to the laser positioning point to detect whether the wafer carrier is accurately placed at the laser positioning point. The laser positioning method is more accurate, and the laser positioning can be combined with other fixed marker points to simultaneously position the edge of the wafer carrier, which can play a foolproof role, so that the wafer carrier is accurately placed in the target position, improving the positioning accuracy of the wafer carrier. Furthermore, when the wafer carrier is accurately positioned in the target position, it can avoid the wafer carrier blocking the high-pressure water jet of the polishing equipment, thereby effectively avoiding the formation of weak cleaning areas due to the wafer carrier blocking the water jet, and thus avoiding the formation of a glaze layer on the surface of the polishing pad due to the presence of weak cleaning areas, thereby improving the glazing phenomenon of the product. Attached Figure Description

[0039] Figure 1 A top view showing the trajectory of a high-pressure cleaning water jet on the surface of a polishing pad in a polishing device;

[0040] Figure 2 This is a partial schematic diagram showing the spraying of a high-pressure cleaning water jet onto the surface of a polishing pad in a polishing equipment.

[0041] Figure 3 The diagram illustrates the spraying of a high-pressure cleaning water jet onto a polishing pad. (a) shows the water jet not being blocked by the polishing pad, and (b) shows the water jet not being blocked by the polishing pad.

[0042] Figure 4 This diagram illustrates the distribution of positioning points in the wafer carrier position detection device provided in this embodiment of the present disclosure.

[0043] Figure 5 A cross-sectional view showing the structure of the polishing equipment provided in the embodiments of this disclosure;

[0044] Figure 6 A schematic diagram showing the peripheral structure of a wafer carrier. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0046] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0047] Before providing a detailed description of the wafer carrier position detection device and method, and polishing equipment provided in the embodiments of this disclosure, the following description of the related technologies is provided:

[0048] In wafer manufacturing, wafers are typically placed in sealed, clean containers or cassettes, and robotic arms automatically handle the loading and unloading operations between these containers / cassettes and the process chamber to prevent contamination by foreign particles. In a known double-sided polishing process, multiple wafer carriers are typically located within the process chamber of the double-sided processing equipment. Each wafer carrier has one or more holding holes for placing wafers. The wafer carriers are connected to a motor controller that drives them to rotate by a specific angle. During the loading and unloading operation, the wafer carrier first rotates by a certain angle under the control of the motor controller, positioning one of the holding holes at a designated loading / unloading position. The robotic arm then moves to directly above this holding hole to perform the loading or unloading operation.

[0049] Before the double-sided polishing operation begins, the wafer carrier needs to be placed on the placement area of ​​the polishing pad. Then, a robotic arm horizontally places the wafer into the holding hole of the wafer carrier, allowing the wafer carrier to move and polish both the top and bottom surfaces. It is known that the movement of the wafer carrier is driven by the engagement of the teeth around its periphery with inner and outer pin rings. During polishing, multiple wafer carriers are simultaneously placed on the polishing pad. These wafer carriers revolve together around the center of the polishing pad while also rotating on their own centers, ensuring that each wafer carried by each wafer carrier is polished over a larger area of ​​the polishing pad, thereby improving polishing uniformity.

[0050] During double-sided polishing, due to the inherent instability of the chemical mechanical polishing process, silicates generated by the reaction between the polished wafer and the alkaline polishing solution are prone to accumulate in the solution. If the cleaning capacity is abnormal, the reaction products are very likely to saturate and precipitate in the polishing pad, polishing solution pipeline, and storage tank, producing white or yellowish-brown precipitates, i.e., the equipment becomes glazed.

[0051] The presence of these precipitates can cause inconvenience to daily maintenance and cleaning of equipment, or, more seriously, cause them to fall off and accumulate on the surface of the polishing pad during material circulation. As the wafer carrier moves, they periodically accumulate to form an enamel layer, resulting in uneven surface roughness distribution of the polishing pad. These enamel layers repeatedly grind the product, leading to product defects. The main product defects are microparticle contamination or micro-scratches.

[0052] The presence of a glaze layer on the surface of the polishing pad can cause ring marks or yellowing on the surface of the polished product; this is known as glazing. Glazing of polished products can be further classified into ring-shaped glazing, band-shaped glazing, and composite glazing.

[0053] In related technologies, there is a lack of in-depth and systematic research on the causes of glazing, and no effective experience has been accumulated. Typically, the method to solve ring-shaped glazing in products is to trim the surface of the polishing pad to remove the glaze layer and restore the surface roughness. However, as the polishing pad surface wears down, fixed trimming conditions can no longer guarantee a stable removal rate throughout the pad's lifespan. Replacing the polishing pad with a new one, on the other hand, increases costs.

[0054] The inventors of this application analyzed the glazing phenomenon in polished products and found that, based on the ring marks and yellowing state, the glazing phenomenon can be further divided into ring-shaped glazing, banded glazing, and composite glazing. For ring-shaped glazing, there are clear boundaries, and the yellowing marks correspond clearly one-to-one with the teeth of the wafer carrier. For banded glazing, the edges are relatively indistinct, with a gradual yellowing process, and it is relatively mild. For composite glazing, it possesses the characteristics of banded glazing, with a gradual deepening of yellowing, but there are sudden deepening ring-shaped glazing marks during the yellowing process. Based on the severity of glazing and its impact on subsequent products, appropriate limits were set according to the severity level to classify the samples.

[0055] The inventors of this application have analyzed the causes of glazing in polished products, and the main causes of glazing are as follows:

[0056] Firstly, chemical causes: During the double-sided polishing process, due to the inherent instability of the chemical mechanical polishing process, the silicates generated by the reaction between the silicon wafer and the alkaline polishing solution after polishing are prone to accumulate in the solution. If the cleaning ability after polishing is abnormal, the reaction products are very likely to saturate and precipitate in the polishing pad, polishing solution pipeline and storage tank, producing different white or yellowish-brown precipitates, which causes the equipment to glaze.

[0057] Secondly, physical accumulation: During normal double-sided polishing, the micropores in the polishing pad can contain the glazing products to a certain extent. However, as the polishing process continues, the products gradually accumulate. Therefore, after a certain processing time, the processed products in the micropores saturate and precipitate, producing glazing products that are visible to the naked eye.

[0058] Thirdly, regarding the annular glazing, its cause lies in the physical obstruction of the cleaning water column by the wafer carrier. Specifically, the reasons are analyzed as follows:

[0059] like Figure 1 and Figure 2 As shown, after polishing, when the polishing pad 2 is subjected to high-pressure cleaning, the robotic arm 3 of the high-pressure cleaning unit (HMPJ) moves along the path shown in the figure. Figure 1 The trajectory a, indicated by the dashed arrow, moves between two adjacent placement areas 1, that is, along the gap between the wafer carriers, to spray water jets onto the surface of the polishing pad 2.

[0060] When the wafer carrier is positioned correctly, the teeth on it will not obstruct the water jet, resulting in good cleaning. However, if the wafer carrier is not positioned correctly, the teeth on adjacent wafer carriers will not align with the trajectory of the water jet. This will cause the wafer carrier teeth to physically obstruct the water jet, creating weak cleaning zones on the surface of the polishing pad. Consequently, some areas of the polishing pad will not be effectively cleaned. Simultaneously, the impact and compression of the high-pressure water jet on the polishing pad surface forces glaze products into these weak cleaning zones, leading to localized accumulation of glaze products and the formation of ring-shaped glaze.

[0061] Figure 3 As shown in (a), this is a schematic diagram of the splash transfer when the water column is not blocked by the teeth; Figure 3 As shown in (b), this is a schematic diagram of product sputtering and transfer when the water column is blocked by the teeth. As the blocked area increases, the degree of product sputtering accumulation increases, which matches the glazing phenomenon.

[0062] Based on the above analysis of the causes of ring-shaped glazing, it can be seen that accurately positioning the wafer carrier to the appropriate target position on the polishing equipment to avoid obstructing the water column and prevent wafer carrier position displacement due to human factors can effectively improve ring-shaped and composite glazing.

[0063] Based on this, the present disclosure provides a wafer carrier position detection device, which accurately positions the wafer carrier to a suitable target position, avoiding the obstruction of the high-pressure cleaning water column by the wafer carrier, thereby avoiding the generation of weak cleaning areas, improving the glazing phenomenon of the product, and playing a foolproof role when placing the wafer carrier, avoiding the wafer carrier position deviation caused by human factors.

[0064] The wafer carrier position detection device provided in this disclosure can be used in polishing equipment, including but not limited to double-sided polishing equipment. The polishing equipment includes a polishing pad with multiple placement areas for placing wafer carriers. The wafer carrier has holding holes in which wafers can be placed.

[0065] The wafer carrier position detection device provided in this embodiment is used to place the wafer carrier at a target position within a target placement area. This target position can be one where, when the wafer carrier is placed in the target placement area, the teeth around the wafer carrier do not obstruct the high-pressure cleaning water column.

[0066] like Figure 4 and Figure 5 As shown in the figure, the wafer carrier position detection device provided in this embodiment includes: a plurality of positioning points A, a laser sensor 100, and a processor (not shown in the figure). The plurality of positioning points A are distributed circumferentially around the target placement area B at intervals; in other words, the plurality of positioning points A are arranged at intervals on the same circumference for positioning the edge of the wafer carrier 200. For example, the plurality of positioning points A may include at least three positioning points A arranged in a triangular shape. Among them, at least one positioning point A is a laser positioning point A1, and for example, at least one positioning point A can be a fixed marker point A2.

[0067] The laser sensor 100 is disposed above the polishing pad 10. The laser sensor 100 emits a laser beam toward the laser positioning point A1 and receives the reflected laser signal returned from the laser positioning point A1. The processor is communicatively connected to the laser sensor 100 and is used to compare the reflected laser signal with a preset laser signal to determine whether the wafer carrier 200 is in the target position. The target placement area B refers to a placement area where the wafer carrier 200 is currently to be placed; the preset laser signal refers to the reflected laser signal corresponding to when the wafer carrier 200 is placed in the target position.

[0068] In the above scheme, by setting the laser sensor 100, when the wafer carrier 200 is placed in the target placement area B of the polishing pad 10, the laser sensor 100 can emit a laser to the laser positioning point A1 to detect whether the wafer carrier 200 is placed accurately at the laser positioning point A1. The laser positioning method is more accurate, and the laser positioning can be combined with other fixed marker points A2 to simultaneously position the edge of the wafer carrier 200, which can play a foolproof role, so that the wafer carrier 200 is accurately placed in the target position, thereby improving the positioning accuracy of the wafer carrier 200.

[0069] Furthermore, when the wafer carrier 200 is precisely positioned at the target location, it can avoid the wafer carrier 200 blocking the high-pressure water jet of the polishing equipment, thereby effectively avoiding the formation of weak cleaning areas due to the wafer carrier 200 blocking the water jet, and thus avoiding the formation of a glaze layer on the surface of the polishing pad 10 due to the presence of weak cleaning areas, thereby improving the glazing phenomenon of the product.

[0070] In some exemplary embodiments of this disclosure, such as Figure 4 As shown, there are three positioning points A, which can be arranged in a triangle. One of the positioning points A is the laser positioning point A1, and the other two positioning points A are fixed marker points A2. Thus, when placing the wafer carrier 200, the wafer carrier 200 can be quickly and initially positioned using the two positioning points A. Then, combined with the laser positioning point A1, the wafer carrier 200 can be precisely positioned to the target location using laser positioning.

[0071] It is understood that the specific number of positioning points A is not limited to three, and the number of laser positioning points A1 is not limited to one. For example, in some embodiments, there may be three positioning points A, with one positioning point A being a fixed marker point A2 and the other two positioning points A being laser positioning points A1.

[0072] It should be noted that the fixed marker point A2 can refer to a marker fixedly set on the polishing equipment, and the specific structure of the marker is not limited. For example, the fixed marker point A2 may include, but is not limited to, a marker graphic.

[0073] In some embodiments of this disclosure, such as Figure 4 and Figure 5 As shown, the polishing pad 10 is provided with an inner pin ring 11 and an outer pin ring 12, and the placement area is located in the space between the inner pin ring 11 and the outer pin ring 12.

[0074] Among them, one of the two fixed mark points A2 is located at the position corresponding to the tangent point between the target placement area B and the inner pin ring 11. That is, one of the fixed marks can be located at the position where the wafer carrier 200 and the inner pin ring 11 are engaged.

[0075] The other of the two fixed marker points A2 is located at the position corresponding to the tangent point between the target placement area B and the outer pin ring 12. That is, the other fixed marker can be located at the position where the wafer carrier 200 and the outer pin ring 12 are engaged.

[0076] The laser positioning point A1 may be located on one edge of the target placement area B, near the other placement area.

[0077] Using the above scheme, the two fixed marker points A2 can respectively position the wafer carrier 200 on its radially opposite sides. In actual positioning operations, the wafer carrier 200 can be initially positioned based on the two fixed marker points A2. Furthermore, since the high-pressure cleaning water column is mainly directed towards the gap between two adjacent placement areas, the laser positioning point A1 can be set on the edge of the target placement area B near the other placement area.

[0078] In some embodiments, such as Figure 6 As shown, the wafer carrier 200 includes a carrier body 201 and teeth 202 disposed around the carrier body 201. A tooth gap 203 is formed between adjacent teeth 202, and the tooth gap 203 exposes a portion of the surface of the polishing pad 10.

[0079] The above analysis of the causes of annular glazing shows that when the high-pressure cleaning water column is directed along trajectory a as shown in the figure towards the tooth gap between the two wafer carriers 200, experiments have revealed that when the teeth 202 of the two wafer carriers 200 are directly opposite each other, the tooth gap pattern formed by the two wafer carriers 200 matches the water column trajectory a well, and the water column is not blocked. However, if the teeth 202 of the two wafer carriers 200 are staggered, the resulting tooth gap pattern will not match the water column trajectory, easily blocking the water column and leading to weak cleaning areas and glazing. Therefore, whether the wafer carrier 200 is in the target position refers not only to whether the center of the wafer carrier 200 is in a suitable position, but also to whether the teeth 202 around the wafer carrier 200 are in a suitable position. The laser positioning point A1 is located on one side edge of the wafer carrier 200 near another placement area, and it can be used to identify whether the peripheral teeth 202 of the wafer carrier 200 are in the appropriate position.

[0080] For example, the surface reflectivity of the carrier body 201, the tooth 202, and the polishing pad 10 are different; wherein, the preset laser signal includes at least whether the wafer carrier 200 is at the target position, and the light intensity value of the laser reflected back by the surface of one of the tooth gaps 203 and the tooth 202; the processor is specifically used to compare the light intensity value of the reflected laser signal with the light intensity value of the preset laser signal to determine whether the wafer carrier 200 is at the target position.

[0081] In the above scheme, the laser positioning point A1 can be the position of the tooth 202 of the wafer carrier 200 at the target position, or the position of the tooth gap 203 of the wafer carrier 200 at the target position. Since the surface reflectivity of the carrier body 201, the tooth 202 and the polishing pad 10 are different, the reflected laser signals when the laser hits the carrier body 201, the tooth 202 and the tooth gap 203 will be different when detecting the position of the wafer carrier 200. Therefore, the light intensity value of the reflected laser signal can be compared with the light intensity value of the preset laser signal to determine whether the wafer carrier 200 is at the target position.

[0082] Figure 6 The middle arrow b shows a schematic diagram of the laser beam hitting the vehicle body 201. Figure 6 The middle arrow c shows a schematic diagram of the laser beam hitting the tooth 202; Figure 6 The middle arrow b shows a schematic diagram of the laser beam hitting the tooth gap 203.

[0083] The tooth gap 203 can expose a local surface of the polishing pad 10. Since there is liquid on the surface of the polishing pad 10, the surface reflectivity of the polishing pad 10 is not high, which is less than the surface reflectivity of the carrier body 201 and the tooth 202. Therefore, when the laser hits the tooth gap 203, the light intensity of the reflected laser is not high, which will be lower than the light intensity detected when the laser hits the tooth 202.

[0084] Therefore, in some embodiments, the preset laser signal includes whether the wafer carrier 200 is at the target position, and the first light intensity value reflected back by the surface of the tooth 203. That is, the laser positioning point A1 is set at the position corresponding to the tooth 202. Specifically, when the wafer carrier 200 is placed at the target position without obstructing the high-pressure cleaning water column, the laser is directed towards the position of the tooth 202 to calibrate the wafer carrier 200, and the reflected laser signal at this time is obtained as the preset laser signal.

[0085] The processor is specifically configured to: determine that the wafer carrier 200 is currently at the target position when the light intensity value of the reflected laser signal is equal to the first light intensity value; and determine that the wafer carrier 200 is not currently at the target position when the light intensity value of the reflected laser signal is greater than the first light intensity value.

[0086] Using the above scheme, since there is a difference in surface reflectivity between the polishing pad 10 and the tooth 202 when the laser hits the tooth 202, the reflected laser signal that the laser just reaches the tooth 202 when the wafer carrier 200 is in the target position is set as the preset laser signal. Therefore, the reflected laser signal is compared with the preset laser signal. When the light intensity value of the reflected laser signal is equal to the first light intensity value, it is determined that the wafer carrier 200 is in the target position; otherwise, it is determined that the wafer carrier 200 is not in the target position.

[0087] In some embodiments, when it is determined that the wafer carrier 200 is not in the target position, the processor may also issue any appropriate alarm prompt, such as a voice or light.

[0088] In addition, in some embodiments, the preset laser signal also includes a second light intensity value reflected back by the surface of the tooth 202; the processor is also used to compare the light intensity value of the reflected laser signal with the second light intensity value to determine the current offset state of the wafer carrier 200.

[0089] By employing the above scheme, not only can the difference in reflected light intensity at different laser positions be used to determine whether the wafer carrier 200 is at the target position, but it can also further determine the offset state of the wafer carrier 200 when it is not at the target position, providing real-time feedback on the adjustment direction of the wafer carrier 200 and avoiding the tedious operation of blind adjustment due to human factors. Generally, the reflected light intensity when the laser hits the surface of the carrier body 201 is less than the reflected light intensity when the laser hits the surface of the tooth 202, but greater than the reflected light intensity when the laser hits the tooth gap 203. Therefore, specifically, the second light intensity value reflected back by the surface of the tooth 202 can be used as the preset laser signal.

[0090] Specifically, the step of comparing the intensity value of the reflected laser signal with the second intensity value to determine the current offset state of the wafer carrier 200 includes:

[0091] When the light intensity value of the reflected laser signal is equal to the second light intensity value, it is determined that the current offset state of the wafer carrier 200 is that it is deviating from the target position in the circumferential direction of the wafer carrier 200;

[0092] When the light intensity value of the reflected laser signal is less than the second light intensity value, it is determined that the current offset state of the wafer carrier 200 is that it is deviating from the target position in the radial direction of the wafer carrier 200, and the deviation direction is away from the center of the placement area.

[0093] Based on the above scheme, the position of the wafer carrier 200 can be corrected after determining the deviation direction of the wafer carrier 200.

[0094] Furthermore, it should be noted that, in conjunction with the control of the polishing equipment's control host (PC), the laser sensor 100 can be automatically activated at the end of each high-pressure cleaning cycle to detect the position of the wafer carrier 200. When a positional shift of the wafer carrier 200 is detected, an alarm can be triggered in advance to prevent the occurrence of ring-shaped glazing.

[0095] Furthermore, this disclosure also provides a polishing apparatus, including the wafer carrier position detection device provided in this disclosure. The polishing apparatus provided in this disclosure includes, but is not limited to, a double-sided polishing apparatus. For example, when the polishing apparatus provided in this disclosure is a double-sided polishing apparatus, it includes an upper mounting plate 20 and a lower mounting plate 30, and the polishing pad 10 may be disposed on the lower mounting plate 30.

[0096] In some embodiments, as shown in the figures, the laser sensor 100 may be disposed on the upper plate 20. It is understood, of course, that the laser sensor 100 may also be disposed on other components of the polishing apparatus.

[0097] In some embodiments, as shown in the figure, one fixed marker point A2 can be located on the inner pin ring 11, and the other fixed marker point A2 can be located on the outer pin ring 12. It is understood, however, that the arrangement of the fixed marker point A2 is not limited to these methods.

[0098] Obviously, the polishing equipment provided in the embodiments of this disclosure can also have the beneficial effects brought by the wafer carrier position detection device provided in the embodiments of this disclosure, which will not be elaborated here.

[0099] Furthermore, this disclosure also provides a wafer carrier position detection method, which uses the wafer carrier position detection device provided in this disclosure to place the wafer carrier 200 at the target position of the target placement area B in the polishing pad 10; the method includes the following steps:

[0100] Step S01: When placing the wafer carrier 200, the edge of the wafer carrier 200 is positioned using a plurality of positioning points A; wherein, for the laser positioning point A1, the specific steps include the following:

[0101] Step S011: The laser sensor 100 emits a laser towards the laser positioning point A1 and receives the reflected laser signal returned from the laser positioning point A1;

[0102] Step S012: Based on the reflected laser signal and the preset laser signal, determine whether the wafer carrier 200 is at the target position.

[0103] In the above scheme, by setting the laser sensor 100, when the wafer carrier 200 is placed in the target placement area B of the polishing pad 10, the laser sensor 100 can emit a laser to the laser positioning point A1 to detect whether the wafer carrier 200 is accurately placed at the laser positioning point A1. The laser positioning method is more accurate, and the laser positioning can be combined with other fixed marker points A2 to simultaneously position the edge of the wafer carrier 200, which can play a foolproof role, so that the wafer carrier 200 is accurately placed in the target position, improving the positioning accuracy of the wafer carrier 200. Furthermore, when the wafer carrier 200 is accurately positioned to the target position, it can avoid the wafer carrier 200 blocking the high-pressure water jet of the polishing equipment, thereby effectively avoiding the formation of a weak cleaning area due to the wafer carrier 200 blocking the water jet, and thus avoiding the formation of a glaze layer on the surface of the polishing pad 10 due to the presence of a weak cleaning area, thereby improving the glazing phenomenon of the product.

[0104] In some exemplary embodiments of this disclosure, when there are three positioning points A, and the three positioning points A can be arranged in a triangle, with one positioning point A being the laser positioning point A1 and the other two positioning points A being fixed marker points A2, the above step S01 specifically further includes:

[0105] When placing the wafer carrier 200, firstly, the wafer carrier 200 is quickly and initially positioned using the two fixed marker points A2; then, steps S011 and S012 are performed to accurately position the wafer carrier 200 to the target position using the laser positioning point A1.

[0106] In some exemplary embodiments of this disclosure, the preset laser signal includes whether the wafer carrier 200 is at the target position, and the first light intensity value of the laser reflected back by the surface of the tooth gap 203; the above step S011 specifically includes:

[0107] Step S0111: When the light intensity value of the reflected laser signal is equal to the first light intensity value, it is determined that the wafer carrier 200 is currently at the target position;

[0108] Step S0112: When the light intensity value of the reflected laser signal is greater than the first light intensity value, it is determined that the wafer carrier 200 is not currently at the target position.

[0109] For example, the preset laser signal also includes a second light intensity value reflected back by the surface of the tooth 202; after step S0112, step S011 specifically includes:

[0110] Step S0113: When it is determined that the wafer carrier 200 is not currently at the target position, the light intensity value of the reflected laser signal is compared with the second light intensity value to determine the current offset state of the wafer carrier 200.

[0111] For example, step S0113 specifically includes:

[0112] When the light intensity value of the reflected laser signal is equal to the second light intensity value, it is determined that the current offset state of the wafer carrier 200 is that it is deviating from the target position in the circumferential direction of the wafer carrier 200;

[0113] When the light intensity value of the reflected laser signal is less than the second light intensity value, it is determined that the current offset state of the wafer carrier 200 is that it is deviating from the target position in the radial direction of the wafer carrier 200, and the deviation direction is away from the center of the placement area.

[0114] The wafer carrier position detection method provided in this embodiment can also have the corresponding beneficial effects brought by the wafer carrier position detection device provided in this embodiment, which will not be described in detail here.

[0115] The following points need to be explained:

[0116] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0117] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the present disclosure, i.e., these drawings are not drawn to actual scale. It will be understood that when an element such as a layer, film, region or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element or there may be intermediate elements.

[0118] (3) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0119] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. The scope of protection of this disclosure shall be determined by the scope of the claims.

Claims

1. A wafer carrier position detection device for use in a polishing apparatus, the polishing apparatus including a polishing pad having multiple placement areas, the wafer carrier position detection device being used to place the wafer carrier at a target position within a target placement area; characterized in that, The wafer carrier position detection device includes: A plurality of positioning points are spaced apart and distributed circumferentially around the target placement area to position the edge of the wafer carrier, wherein at least one of the positioning points is a laser positioning point; A laser sensor, disposed above the polishing pad, emits a laser beam toward the laser positioning point and receives the reflected laser signal returned from the laser positioning point; and The processor is communicatively connected to the laser sensor and is used to compare the reflected laser signal with a preset laser signal to determine whether the wafer carrier is at the target position. The laser positioning point is located on one edge of the target placement area that is closer to the other placement area; The wafer carrier includes a carrier body and teeth disposed around the periphery of the carrier body. A tooth gap is formed between adjacent teeth, and the tooth gap exposes a portion of the surface of the polishing pad. The surface reflectivity of the carrier body, the teeth, and the polishing pad is different. The preset laser signal includes at least whether the wafer carrier is at the target position and the light intensity value of the laser reflected back by the surface of one of the tooth gaps or the teeth. The processor is specifically used to compare the light intensity value of the reflected laser signal with the light intensity value of the preset laser signal to determine whether the wafer carrier is at the target position.

2. The wafer carrier position detection device according to claim 1, characterized in that, There are three positioning points, one of which is the laser positioning point, and the other two are fixed marker points.

3. The wafer carrier position detection device according to claim 2, characterized in that, The polishing pad is provided with an inner pin ring and an outer pin ring. The placement area is located in the space between the inner pin ring and the outer pin ring. One of the two fixed marking points is located at the position corresponding to the tangent point between the target placement area and the inner pin ring, and the other is located at the position corresponding to the tangent point between the target placement area and the outer pin ring.

4. The wafer carrier position detection device according to claim 1, characterized in that, The surface reflectivity of the polishing pad is less than that of the carrier body and the teeth; wherein, the preset laser signal includes a first light intensity value of the laser reflected back by the tooth gap surface when the wafer carrier is at the target position; the processor is specifically used for: When the intensity value of the reflected laser signal is equal to the first intensity value, it is determined that the wafer carrier is currently at the target position; When the intensity of the reflected laser signal is greater than the first intensity value, it is determined that the wafer carrier is not currently at the target position.

5. The wafer carrier position detection device according to claim 4, characterized in that, The preset laser signal also includes a second light intensity value of the laser reflected back by the surface of the tooth; the processor is further configured to compare the light intensity value of the reflected laser signal with the second light intensity value to determine the current offset state of the wafer carrier.

6. The wafer carrier position detection device according to claim 5, characterized in that, The step of comparing the intensity value of the reflected laser signal with the second intensity value to determine the current offset state of the wafer carrier specifically includes: When the light intensity value of the reflected laser signal is equal to the second light intensity value, it is determined that the current offset state of the wafer carrier is that it is deviating from the target position in the circumferential direction of the wafer carrier; When the light intensity value of the reflected laser signal is less than the second light intensity value, it is determined that the current offset state of the wafer carrier is that it is deviating from the target position in the radial direction of the wafer carrier, and the deviation direction is away from the center of the placement area.

7. A polishing device, characterized in that, Includes the wafer carrier position detection device as described in any one of claims 1 to 6.

8. A method for detecting the position of a wafer carrier, characterized in that, Using the wafer carrier position detection device as described in any one of claims 1 to 6, the wafer carrier is placed at the target position in the target placement area of ​​the polishing pad; the method includes the following steps: When placing the wafer carrier, the edges of the wafer carrier are positioned using a plurality of positioning points, wherein... For the laser positioning point, the laser sensor emits a laser towards the laser positioning point and receives the reflected laser signal returned from the laser positioning point; Based on the reflected laser signal and the preset laser signal, it is determined whether the wafer carrier is at the target position.

9. The wafer carrier position detection method according to claim 8, characterized in that, The preset laser signal includes a first light intensity value when the wafer carrier is at the target position and the laser is reflected back by the tooth gap surface; The step of determining whether the wafer carrier is at the target position based on the reflected laser signal and the preset laser signal specifically includes: When the intensity value of the reflected laser signal is equal to the first intensity value, it is determined that the wafer carrier is currently at the target position; When the intensity of the reflected laser signal is greater than the first intensity value, it is determined that the wafer carrier is not currently at the target position.

10. The wafer carrier position detection method according to claim 9, characterized in that, The preset laser signal also includes a second light intensity value of the laser reflected back by the surface of the tooth; The step of determining whether the wafer carrier is at the target position based on the reflected laser signal and the preset laser signal specifically includes: The intensity value of the reflected laser signal is compared with the second intensity value to determine the current offset state of the wafer carrier.

11. The wafer carrier position detection method according to claim 10, characterized in that, The step of comparing the intensity value of the reflected laser signal with the second intensity value to determine the current offset state of the wafer carrier specifically includes: When the light intensity value of the reflected laser signal is equal to the second light intensity value, it is determined that the current offset state of the wafer carrier is that it is deviating from the target position in the circumferential direction of the wafer carrier; When the light intensity value of the reflected laser signal is less than the second light intensity value, it is determined that the current offset state of the wafer carrier is that it is deviating from the target position in the radial direction of the wafer carrier, and the deviation direction is away from the center of the placement area.

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