Semiconductor wafer polishing detection system and semiconductor wafer polishing detection method

Abstract

The invention discloses a grinding detection system of a semiconductor wafer and a grinding detection method of the semiconductor wafer, the grinding detection system of the semiconductor wafer comprises a grinding head which is provided with a motor to drive the grinding head to rotate, a retaining ring which is fixed at a bottom of the grinding head, the retaining ring comprises a plurality of grooves, and the grooves are arranged in the grooves. The polishing device comprises a holding ring, a polishing head arranged on the holding ring, a polishing pad arranged below the polishing head, and a laser sensor arranged beside the holding ring, and the laser sensor is used for measuring the depth of the plurality of grooves on the holding ring. According to the invention, the depth of the groove of the retaining ring can be monitored in real time, and the reliability of the manufacturing process can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor manufacturing processes, and particularly to a method for detecting the grinding process of a semiconductor wafer, which helps to monitor the groove depth of a retaining ring in real time and improves the reliability of the manufacturing process. BACKGROUND

[0002] Chemical Mechanical Polishing (CMP) is an indispensable key step in the semiconductor manufacturing process. Its main purpose is to combine chemical and mechanical effects to perform planarization treatment on the wafer surface, remove excess material, and ensure wafer surface flatness to meet the requirements of subsequent photolithography, thin film deposition, and other processes.

[0003] CMP is usually carried out in a dedicated grinding equipment. The wafer is fixed on a carrier, such as a grinding head, and placed upside down on a grinding pad. The grinding pad is usually made of porous polymer material, which has elasticity and wear resistance. During the grinding process, slurry is introduced between the wafer and the grinding pad. The slurry is a liquid containing abrasive particles and chemical reagents.

[0004] When the grinding head rotates, relative motion occurs between the wafer and the grinding pad, while the abrasive particles in the slurry mechanically grind the wafer surface. At the same time, the chemical reagents in the slurry chemically react with the wafer surface material, making the material soften or dissolve, and more easily removed by mechanical grinding. Through the synergy of chemical and mechanical effects, CMP can efficiently remove the protrusions and unevenness on the wafer surface, achieving planarization.

[0005] CMP has multiple applications in semiconductor manufacturing, mainly including 1. Shallow Trench Isolation (STI): In the STI manufacturing process, CMP is used to remove excess silicon oxide, making the isolation layer flush with the wafer surface, ensuring the correct formation of subsequent components. 2. Metal Interconnection: CMP is a key step in the manufacturing process of metal interconnections (such as copper, tungsten, etc.). It is used to remove excess metal, making the metal lines flush with the surrounding dielectric layer, ensuring the reliability of electrical connections. 3. Multi-layer chip: In multi-layer chip manufacturing, CMP is used to planarize the surface of each layer of chip, ensuring that each layer can be accurately aligned to form reliable electrical connections.

[0006] Although CMP is an important technology in semiconductor manufacturing, it also faces some challenges. For example, the composition of the slurry and the grinding parameters need to be precisely controlled to ensure the grinding effect and the quality of the wafer surface. In addition, defect control during the CMP process is also an important issue. SUMMARY

[0007] A semiconductor wafer polishing detection system includes a polishing head, a motor driving the polishing head to rotate, a retaining ring fixed to a bottom of the polishing head, wherein the retaining ring includes a plurality of grooves, a polishing pad located below the polishing head, and a laser sensor located beside the retaining ring, wherein the laser sensor is used to measure a depth of the plurality of grooves on the retaining ring.

[0008] A semiconductor wafer polishing detection method includes providing a wafer polishing detection system including a polishing head, a motor driving the polishing head to rotate, a retaining ring fixed to a bottom of the polishing head, wherein the retaining ring includes a plurality of grooves, a first polishing pad located below the polishing head, and a laser sensor located beside the retaining ring, installing a wafer on the bottom of the polishing head and inside the retaining ring, the laser sensor performing a first measurement step to measure a first depth of the plurality of grooves on the retaining ring, and performing a first polishing step on the wafer.

[0009] In summary, the applicant found that the depth of the grooves on the retaining ring installed around the wafer in the current semiconductor wafer polishing step affects the amount of polishing liquid flowing below the wafer. If the grooves are too shallow, the polishing quality will be poor, so the retaining ring needs to be replaced regularly. Since the current semiconductor wafer polishing system does not have a method to detect the grooves of the retaining ring in real time during the manufacturing process, it can only observe the groove depth on the retaining ring in a regular manner, so in some cases it may not be possible to immediately detect that the groove depth on the retaining ring is too shallow to affect the quality of the manufacturing process. The present application provides an improved semiconductor wafer polishing detection system and semiconductor wafer polishing detection method, which mainly additionally sets a laser sensor in the system, and the laser emitted by the laser sensor can be used to detect the depth value of the grooves of the retaining ring. Therefore, in a continuous polishing manufacturing process including many polishing steps, the groove depth on the retaining ring can be detected immediately before or after each polishing step. In this way, the manufacturer can receive information in advance before the grooves on the retaining ring are consumed and need to be replaced, and the retaining ring can be replaced in time. The present application has the advantages of improving the reliability of the manufacturing process, simplifying the manufacturing process, improving the efficiency of the manufacturing process, etc. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to make the following text easier to understand, the drawings can be referred to while reading the present application and its detailed text. The specific embodiments of the present application are explained in detail by the specific embodiments herein and with reference to the corresponding drawings, and the principles of the specific embodiments of the present application are explained. In addition, in order to be clear, the features in the drawings may not be drawn according to the actual proportions, so the sizes of some features in some drawings may be intentionally enlarged or reduced.

[0011] Figure 1 Fig. 1 is a schematic diagram of a semiconductor polishing apparatus according to an embodiment of the present application;

[0012] Figure 2 Fig. 2 is a schematic diagram of a partial cross-sectional structure of the semiconductor polishing apparatus of Fig. 1; Figure 1

[0013] Figure 3 Fig. 3 is a schematic diagram of a structure of a retaining ring and a wafer;

[0014] Figure 4 Fig. 4 is a schematic diagram of a cross-sectional structure of a semiconductor polishing apparatus according to another embodiment of the present application;

[0015] Figure 5 Fig. 5 is a schematic diagram of a cross-sectional structure of a retaining ring according to an embodiment of the present application.

[0016] Main component symbol explanation

[0017] 10: stage

[0018] 11: polishing pad

[0019] 11': polishing pad

[0020] 12: motor

[0021] 13: polishing head

[0022] 14: retaining ring

[0023] 15: groove

[0024] 16: polishing liquid nozzle

[0025] 18: polishing pad conditioner

[0026] 20: laser sensor

[0027] L: laser

[0028] S: polishing liquid

[0029] W: wafer DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the present application, preferred embodiments of the present application are described below with reference to the accompanying drawings, and the effects and purposes of the present application are explained in detail.

[0031] ​For convenience of explanation, the drawings of the present application are only schematic and are non-to-scale for the purpose of easier understanding of the present application. The relative positions of the various elements in the drawings described herein should be understood as referring only to the position of these elements in the drawing and are not intended to be limiting in nature. The drawings are therefore to be regarded as being illustrative and not restrictive.

[0032] Although the present application uses the words first, second, third, etc. to describe elements, components, regions, layers, and / or sections, it should be understood that such elements, components, regions, layers, and / or sections should not be limited by such words. Such words are only used to distinguish one element, component, region, layer, and / or section from another element, component, region, layer, and / or section, and do not inherently imply and represent any previous ordinal number of the element, nor represent the arrangement order of one element with respect to another element, or the order of manufacturing method. Therefore, the first element, component, region, layer, or section discussed below can also be referred to as the second element, component, region, layer, or section, without departing from the scope of the embodiments of the present application.

[0033] The words "about" or "substantially" mentioned in the present application generally mean within 20% of a given value or range, such as within 10%, or within 5%, or within 3%, or within 2%, or within 1%, or within 0.5%. It should be noted that the numbers provided in the specification are approximate numbers, i.e. the meaning of "about" or "substantially" is implied without specific indication of "about" or "substantially".

[0034] The words "coupled", "coupling", "electrically connected" mentioned in the present application include any direct and indirect electrically connecting means. For example, if the first component is described as being coupled to the second component in the specification, it means that the first component can be directly electrically connected to the second component, or indirectly electrically connected to the second component through other devices or connecting means.

[0035] Although the following is to describe the invention of the present application through specific embodiments, the inventive principles of the present application can also be applied to other embodiments. In addition, in order not to make the spirit of the present application obscure, specific details will be omitted, which are within the knowledge of those skilled in the art.

[0036] Reference is made to Figure 1 , Figure 1 A structure schematic diagram of a semiconductor polishing apparatus, also known as a chemical mechanical polishing (CMP) device, of an embodiment of the present application is shown. The device is intended to perform planarization processing on the surface of a wafer to improve the flatness thereof to meet the requirements of the surface quality of the wafer in high-tech industries such as semiconductor manufacturing. In the present application, the wafer is a circular substrate used in the semiconductor manufacturing industry, and the wafer is not limited to a circular shape. For example, the wafer can be a rectangular substrate. Figure 1, Semiconductor polishing apparatus includes a stage 10, a polishing pad 11, a motor 12, a polishing head 13, a wafer W, a retaining ring 14, a polishing liquid spray head 16 sprays polishing liquid S onto the polishing pad 10, and a polishing pad conditioner 18.

[0037] The stage 10 functions to support the polishing pad 11 and provides precise movement and rotation control during polishing. The design of the stage 10 takes into account the size, weight, and material properties of the wafer W to ensure stability during polishing and resistance to external disturbances. The stage 10 can move along a plane to ensure uniform contact of the wafer W with the polishing pad 11, avoiding uneven polishing due to uneven contact. In addition, the stage 10 also has a rotation function, through rotation, the wafer W surface everywhere can receive the treatment of the polishing liquid S, to ensure the consistency of the polishing effect. The movement and rotation of the stage 10 are usually controlled by high-precision servo motors or other driving devices, and precise positioning and speed control are achieved through a closed-loop control system.

[0038] The polishing pad 11 is a rough surface, and its surface properties directly affect the polishing effect. The polishing pad 11 is usually made of porous materials such as polyurethane, with specific roughness and porosity. These properties are designed to provide a polishing surface that allows the polishing liquid S to be evenly distributed and fully contact the wafer W surface. The roughness of the polishing pad 11 affects the polishing rate and material removal rate, while the porosity affects the flowability of the polishing liquid S and the removal efficiency of worn particles. In addition, the material of the polishing pad 11 also needs to have good wear resistance and chemical resistance to withstand mechanical stress and chemical corrosion during polishing.

[0039] The wafer W can be fixed on the polishing head 13 using vacuum suction, mechanical clamping, or electrostatic adsorption. The motor 12 is connected to the polishing head 13, and the function of the motor 12 is to drive the polishing head 13 to rotate and move up and down. That is, when the polishing step is needed, the motor applies uniform downward pressure, so that the fixed wafer W rotates and contacts the polishing pad 11, and when the polishing step is completed, the motor stops rotating and moves the polishing head 13 upward and away from the polishing pad 11. The main function of the polishing head 13 is to fix the wafer W, and the design of the polishing head 13 must ensure that the wafer W remains stable during polishing to avoid slipping or falling off. At the same time, the polishing head 13 also needs to have good pressure control ability to achieve uniform material removal and surface planarization. The polishing head 13 usually includes a backing film (not shown in the figure) for uniform pressure distribution and protection of the wafer W from damage. The material and structure design of the backing film has an important influence on the polishing effect, and needs to be selected according to the type, size, and polishing requirements of the wafer W.

[0040] A retaining ring 14 is provided at the periphery of the polishing head 13 to form a barrier that prevents the polishing liquid S from overflowing or flowing underneath the wafer W. The retaining ring 14 helps to ensure uniform distribution of the polishing liquid S on the polishing pad 11, thereby improving the uniformity of the polishing effect. The design of the retaining ring 14 typically takes into account factors such as the viscosity, surface tension, and flow characteristics of the polishing liquid S, as well as the rotational speed of the polishing pad 11, to ensure effective prevention of overflow and flow-in of the polishing liquid S. The material selection for the retaining ring 14 is also crucial, as it needs to have good chemical resistance and wear resistance to withstand the long-term abrasive action of the polishing liquid S.

[0041] The main function of the polishing liquid nozzle 16 is to spray the polishing liquid S onto the surface of the polishing pad 11 at a specific flow rate and pressure. The design of the polishing liquid nozzle 16 needs to ensure stable flow rate and uniform distribution of the polishing liquid S to achieve optimal polishing results. To prevent chemical corrosion and ensure the purity of the polishing liquid, the polishing liquid nozzle 16 is typically made of corrosion-resistant materials such as stainless steel or PTFE (Polytetrafluoroethylene). These materials have excellent chemical resistance and wear resistance, which can ensure that the polishing liquid S is not contaminated during transportation and prolong the service life of the polishing liquid nozzle 16. In addition, the pipe diameter size, the number of nozzles, etc. can be adjusted according to actual needs, for example, according to the required flow rate and pressure of the polishing liquid S. For example, a larger pipe diameter can provide a higher flow rate, but it may cause the pressure of the polishing liquid S to drop. A smaller pipe diameter can provide a higher pressure, but it may limit the flow rate of the polishing liquid S.

[0042] The polishing liquid S is an essential part of the chemical mechanical polishing process. The polishing liquid S usually contains abrasive particles (such as cerium oxide, silicon oxide) and chemical reagents (such as potassium hydroxide). The abrasive particles play a mechanical grinding role in the polishing process, removing surface materials by rubbing against the wafer W surface. The chemical reagents promote material removal through chemical reactions, accelerating the polishing process. For different wafer W materials and polishing requirements, the appropriate polishing liquid S formula needs to be selected, and its composition and concentration need to be accurately controlled.

[0043] The main function of the polishing pad conditioner 18 is to condition the surface of the polishing pad 11 to maintain its flatness and roughness, ensuring the stability and uniformity of the polishing process. During the polishing process, the surface of the polishing pad 11 will gradually wear out, affecting the polishing effect. The polishing pad conditioner 18 removes the worn layer on the surface of the polishing pad 11 to maintain its optimal state. The polishing pad conditioner 18 usually contains one or more diamond particles, which have extremely high hardness and wear resistance, and can effectively remove the worn material on the surface of the polishing pad 11. In addition, the polishing pad conditioner 18 can also control the polishing rate and material removal rate by adjusting the roughness of the polishing pad 11 surface.

[0044] Figure 2 isFigure 1 A partial cross-sectional structural diagram is provided. For simplicity, some components are not shown in the drawing; only the stage 10, polishing pad 11, motor 12, polishing head 13, wafer W, retaining ring 14, and polishing slurry S (located on the polishing pad 11) are shown. Among these components, the retaining ring 14 is mounted below the polishing head 13 and surrounds the wafer W. During polishing, the polishing slurry S on the polishing pad 11 enters the bottom of the wafer W through the structural design of the retaining ring 14, achieving effective polishing. The retaining ring 14 is typically made of wear-resistant materials, such as high-hardness metal alloys or wear-resistant ceramics, to maintain a long service life in high-wear environments.

[0045] Please refer to Figure 3 , Figure 3 A schematic diagram of the retaining ring and wafer structure is shown. From Figure 2 and Figure 3 As can be seen, the retaining ring 14 has multiple grooves 15. The purpose of these grooves 15 is to allow the polishing slurry S to pass through the grooves and enter the area below the wafer W, or to discharge excess polishing slurry S through the grooves 15 when necessary. The grooves 15 can discharge debris, particles and other impurities generated during the polishing process, as well as excess polishing slurry S, to ensure the cleanliness of the polishing area and prevent impurities from damaging the wafer W.

[0046] However, as the grinding process continues, the groove 15 on the retaining ring 14 gradually becomes shallower. This is because the abrasive particles in the grinding slurry S wear down the bottom surface of the retaining ring 14, simultaneously reducing the depth of the groove 15. When the depth of the groove 15 drops below a critical value, the flow of the grinding slurry S will be obstructed, preventing it from smoothly entering or exiting the bottom of the wafer W. This directly affects the uniformity and effectiveness of the grinding. At this point, the retaining ring 14 must be replaced. Otherwise, due to insufficient depth of the groove 15, the grinding slurry S will be unable to properly enter the bottom of the wafer W through the groove, or will not be able to effectively exit the bottom of the wafer W, thus affecting the effect and quality of the grinding process.

[0047] In existing manufacturing processes, manufacturers need to periodically replace the retaining ring 14 to maintain grinding quality. However, because different types of polishing fluids S cause varying degrees of wear on the grooves 15 of the retaining ring 14, in some cases, the grooves 15 of the retaining ring 14 may wear out faster than expected. For example, some polishing fluids S contain harder abrasive particles, which cause faster wear on the grooves 15, resulting in the grooves 15 becoming insufficient to maintain normal polishing fluid S flow before the scheduled replacement time. This means that the grooves 15 of the retaining ring 14 may become insufficient before the replacement time set by the manufacturer, forcing premature replacement of the retaining ring 14.

[0048] However, in the current manufacturing process, the grinding manufacturing process is often composed of multiple continuous grinding steps, that is, multiple grinding is performed in one complete grinding manufacturing process, for example, multiple grinding steps can be performed using multiple grinding pads with different degrees of roughness. In order to improve production efficiency, the operator usually manually checks the retaining ring 14 after completing all manufacturing processes. This approach also has some potential risks, that is, if the groove 15 depth of the retaining ring 14 is reduced below the critical value too early, it will not be discovered in time, which will affect the quality of the subsequent grinding step. In addition, since the groove 15 depth of the retaining ring 14 needs to be checked by manual inspection each time, the grinding step cannot be performed at the time of inspection, and manual inspection may have other error factors, such as misjudging the replacement inspection ring time, or forgetting to replace at that time, which is not conducive to the efficiency of the manufacturing process over time.

[0049] Therefore, in order to improve the situation of the above-mentioned embodiment, Figure 4 A cross-sectional structure diagram of a semiconductor grinding machine table according to another embodiment of the present application is provided. In Figure 4 In this embodiment, a laser sensor 20 is provided beside the retaining ring 14 and aligned with the retaining ring 14 in the horizontal direction. It is worth noting that although the laser sensor 20 is aligned with the retaining ring 14 in the horizontal direction in this embodiment, the present application is not limited thereto, and in other embodiments of the present application, the laser sensor 20 can be provided at other positions, such as diagonally below the retaining ring 14, and such variations also belong to the scope of the present application.

[0050] As mentioned above, a complete grinding manufacturing process can include multiple grinding steps, for example, the same wafer can first be subjected to preliminary grinding with a coarser grinding pad, and then subjected to the next grinding with a finer grinding pad. Depending on the requirements of the manufacturing process, it is also possible to undergo more grinding steps. The interval between each grinding step, the grinding head 13 will stop rotating and another grinding pad will be replaced below the grinding head. Before or after each grinding step, the laser sensor 20 can emit laser L and detect the depth of the groove 15 on the retaining ring 14. For example, the working principle of the laser sensor 20 is to emit laser L to the bottom of the groove 15 and receive the reflected laser L. By measuring the time difference between the emitted and received light beams, the distance traveled by the laser L can be calculated, that is, the depth of the groove 15. In order to ensure measurement accuracy, the laser sensor 20 usually takes multiple measurements and takes the average value to reduce errors. In addition, the laser sensor 20 can also improve measurement accuracy and stability by adjusting the emission angle or using multiple receivers.

[0051] For example, first, a first polishing step can be performed on the wafer W by the polishing pad 11. Before the first polishing step, the laser sensor 20 can detect the depth of the groove 15 of the retaining ring 14, and record the value as A1. Then, the polishing head 13 is lowered and rotated close to the polishing pad 11 to perform the first polishing step on the wafer W. After the first polishing step, the polishing head 13 is raised again, and the retaining ring 14 is parallel to the laser sensor 20 in the horizontal direction. At this time, the laser sensor 20 can detect the depth of the groove 15 of the retaining ring 14 again, and record the value as A2. It is worth noting that at this time, the entire polishing manufacturing process has not been completed, so the values A1 and A2 are values measured during the polishing step. As an example of the present embodiment, the wafer W can need different thicknesses of polishing pads for the polishing step. Therefore, in the first polishing step, the polishing pad 11 can be used first, and after the polishing head 13 is raised, the second polishing step can be continued. At this time, another polishing pad 11' can be moved to the position of the original polishing pad 11, and the subsequent polishing head 13 can be lowered again and perform the second polishing step with the polishing pad 11'. The thickness of the polishing pad 11' can be different from that of the polishing pad 11, for example, the particles of the polishing pad 11' are finer than those of the polishing pad 11, so that the wafer W can be polished more finely.

[0052] In other words, between the first polishing step and the second polishing step, the polishing head 13 is raised and stopped, and at this time, the laser sensor 20 can detect the depth of the groove 15 of the retaining ring 14 and record it into a system (such as a computer). If it is found during the recording of the depth of the groove 15 that the depth of the groove 15 has dropped below a predetermined value, a warning message can be sent to the manufacturer to remind the manufacturer to replace the retaining ring 14. In the present embodiment, the initial depth of the groove 15 of the newly replaced retaining ring 14 is about 3.55 microns, and when the depth of the groove 15 of the retaining ring 14 drops to about 2.25 microns, a new retaining ring 14 needs to be replaced. However, the above values are only one example of the present application, and the present application is not limited thereto. Therefore, the method provided by the present application can detect the depth of the groove 15 of the retaining ring 14 during the polishing manufacturing process, thereby improving the reliability of the manufacturing process.

[0053] It is understood that although only the first grinding step and the second grinding step are mentioned in the embodiments of the present application, in some embodiments, more grinding steps can be performed on the wafer W, that is, after the second grinding step (using the grinding pad 11') is completed, the grinding head 13 is temporarily stopped and raised, and then another grinding pad is moved below the grinding head 13, and a subsequent third grinding step is expected to be performed. At the same time, the depth of the groove 15 of the retaining ring 14 can be measured again by the laser sensor 20 when the grinding head 13 is temporarily stopped. Such a variant is also within the scope of the present application.

[0054] It is worth noting that the time point at which the present application measures the groove 15 of the retaining ring 14 by the laser sensor 20 is when the grinding head 13 is stopped rotating, that is, before grinding or when the grinding pad needs to be switched during grinding. Therefore, at this time point, the grinding head 13 is in a temporary waiting state (for example, waiting for another grinding pad to move below), and the groove depth measurement is performed during this waiting time, so it does not affect the original grinding process time. In other words, the semiconductor wafer grinding system provided by the present application has the same process time as the existing semiconductor grinding system, that is, no additional detection time is required.

[0055] In other applications of the present application, the service life of the retaining ring 14 can also be extended by designing the shape of the groove 15 on the retaining ring 14. For example, Figure 5 A cross-sectional structure diagram of a retaining ring according to an embodiment of the present application is shown. As Figure 5 shown, from the direction of the cross-sectional line A-A' of the retaining ring 14, Figure 3 the depth of the groove 15 near the outside of the retaining ring 14 (that is, near the boundary of the grinding head 13) is shallow, and the depth of the groove 15 near the inside of the retaining ring 14 (that is, near the center of the grinding head 13) is deep, and from the direction of the cross-sectional line B-B' of the retaining ring 14, Figure 3 the groove 15 of the retaining ring 14 is not designed to be rectangular, but is designed to be wide at the top and narrow at the bottom. By designing the shape of the groove 15 in this way, as the retaining ring 14 is worn, the width of the bottom contact with the grinding pad 11 becomes larger and larger, that is, the reduced flow rate of the grinding liquid S after wear can be compensated by increasing the width of the groove 15, thereby extending the service life of the entire retaining ring 14. It is understood that the above-mentioned shape of the groove 15 of the retaining ring 14 is only one example of the present application, and in fact, in order to achieve similar results, the groove 15 can also be designed in other shapes, which are also within the scope of the present application.

[0056] In combination with the above embodiments, the laser sensor 20 can also be combined with the features of the inverted trapezoidal grooves 15 to create new application modes, such as a multi-stage warning function. For example, when the grooves 15 of the retaining ring 14 are consumed by more than a certain percentage (such as more than 80% of the consumed depth, but not limited to this), a first warning can be issued to inform the user that the retaining ring 14 is about to be consumed and needs to be replaced. At this time, the user can adjust the manufacturing process as appropriate, such as avoiding performing a grinding step with coarser particles or higher hardness, so as to avoid accelerating the consumption of the retaining ring 14. When the depth of the grooves 15 of the retaining ring 14 has been consumed to the depth expected to require replacement, a second warning is given to inform the user that the retaining ring 14 needs to be replaced.

[0057] Through the design of the present application, only relatively low-cost component structures, including the laser sensor 20 and the original control system (such as a computer), are needed to detect the depth of the grooves 15 of the retaining ring 14 during the grinding process. At the same time, there is no need for human labor to periodically check the retaining ring, so that the possible shortcomings of manual work (such as inaccurate manual inspection or the possibility of forgetting to check manually) can be avoided, and the reliability of the manufacturing process can be improved. On the other hand, since the labor operation time is saved, the overall productivity is also improved.

[0058] In combination with the above description and drawings, the present application provides a grinding detection system for a semiconductor wafer, mainly referring to Figure 4 , characterized in that it comprises a grinding head 13 driven to rotate by a motor 12, a retaining ring 14 fixed to the bottom of the grinding head 13, wherein the retaining ring 14 comprises a plurality of grooves 15, a grinding pad 11 located below the grinding head 13, and a laser sensor 20 located beside the retaining ring 14, wherein the laser sensor 20 is used to measure the depth of the plurality of grooves 15 on the retaining ring 14.

[0059] In some embodiments of the present application, a wafer W is also included, which is fixed to the bottom of the grinding head 13 and located within the retaining ring 14.

[0060] In some embodiments of the present application, when the wafer W is mounted on the grinding head 13, a bottom surface of the retaining ring 14 is lower than a bottom surface of the wafer W (as shown in Figure 2 , that is, the retaining ring 14 will preferentially contact the grinding pad 11 during the grinding step, and the grinding of the wafer W is mainly performed by the particles in the grinding liquid S).

[0061] In some embodiments of the present application, as viewed from a top view (for example Figure 3 ), the retaining ring 14 is a ring structure and is located around the bottom of the grinding head 13, and the wafer W is located in the center of the ring structure.

[0062] In some embodiments of the present application, the laser sensor 20 is aligned with the retaining ring 14 in an initial horizontal direction.

[0063] In some embodiments of the present application, an analysis system (such as a computer) is further included, connected to the laser sensor 20, and the analysis system further includes an alarm, such as a warning program installed in the computer, which can issue an alarm when the groove depth is too shallow.

[0064] The present application further provides a method for detecting the grinding of a semiconductor wafer, characterized by providing a wafer grinding detection system, which includes a grinding head 13, a motor 12 for rotating the grinding head 13, a retaining ring 14 fixed to the bottom of the grinding head 13, wherein the retaining ring 14 includes a plurality of grooves 15, a first grinding pad 11 located below the grinding head 13, and a laser sensor 20 located beside the retaining ring 14, installing a wafer W on the bottom of the grinding head 13 and inside the retaining ring 14, and the laser sensor 20 performing a first measurement step to measure a first depth Al of the plurality of grooves 15 on the retaining ring 14, and performing a first grinding step on the wafer W.

[0065] In some embodiments of the present application, when the wafer W is installed on the grinding head 13, the bottom surface of the retaining ring 14 is lower than the bottom surface of the wafer W.

[0066] In some embodiments of the present application, before the first grinding step, the retaining ring 14 is located at an initial horizontal position, and the laser sensor 20 is aligned with the retaining ring 14 in the initial horizontal direction.

[0067] In some embodiments of the present application, during the first grinding step, the grinding head 13 starts to rotate and descend, so that the retaining ring 14 is lowered from the initial horizontal position to a first height (i.e. to a height at which the retaining ring 14 can contact the grinding pad 11), and the wafer W is ground on the first grinding pad 11.

[0068] In some embodiments of the present application, after the first grinding step is completed, the grinding head 13 stops rotating and rises, so that the retaining ring 14 returns to the initial horizontal position.

[0069] In some embodiments of the present application, after the first grinding step is completed and the retaining ring 14 returns to the initial horizontal position, the laser sensor 20 performs a second measurement step to measure a second depth A2 of the plurality of grooves 15 on the retaining ring 14.

[0070] In some embodiments of the present application, an analysis system (e.g. a computer) is provided, which is connected to the laser sensor, and the analysis system further comprises an alarm, wherein the alarm is triggered when the first depth Al or the second depth A2 of the plurality of grooves 15 of the retaining ring is below a set value.

[0071] In some embodiments of the present application, the first depth Al is between 2.5 microns and 3.9 microns before the first polishing step is performed (i.e. if the measured groove depth is between these values, the retaining ring does not need to be replaced), and the set value is between 2.0 microns and 2.5 microns (i.e. if the measured groove depth is between these values, the retaining ring needs to be replaced).

[0072] In some embodiments of the present application, after the second measurement step is performed, a second polishing pad 11' is moved under the polishing head, and a second polishing step is performed.

[0073] In some embodiments of the present application, when the wafer W is mounted on the polishing head 13, a bottom surface of the retaining ring 14 is lower than a bottom surface of the wafer W.

[0074] In some embodiments of the present application, as viewed from above, the retaining ring 14 is a ring structure and is located around the bottom of the polishing head 13, and the wafer W is located in the center of the ring structure.

[0075] In some embodiments of the present application, a polishing liquid nozzle 16 is further provided, which sprays a polishing liquid S onto the first polishing pad 11.

[0076] In some embodiments of the present application, in the first polishing step, the polishing liquid S flows from the grooves 15 of the retaining ring 14 to under the wafer W.

[0077] In summary, the applicant found that the groove depth of the retaining ring installed around the wafer affects the amount of polishing liquid flowing to the lower side of the wafer. If the groove is too shallow, the polishing quality will be poor, and the retaining ring needs to be replaced regularly. Since the current semiconductor wafer polishing system does not have a method for detecting the groove of the retaining ring during the manufacturing process, it can only observe the groove depth of the retaining ring in a regular manner. Therefore, in some cases, the shallow groove depth of the retaining ring may not be detected immediately, which may affect the quality of the manufacturing process. The present application provides an improved semiconductor wafer polishing detection system and a semiconductor wafer polishing detection method. A laser sensor is additionally provided in the system, and the laser emitted by the laser sensor can be used to detect the depth value of the groove of the retaining ring. Therefore, in a continuous polishing manufacturing process including many polishing steps, the groove depth of the retaining ring can be detected immediately before or after each polishing step. In this way, the manufacturer can receive information in advance before the groove of the polishing ring is consumed and needs to be replaced, and the retaining ring can be replaced in time. The present application has the advantages of improving the reliability of the manufacturing process, simplifying the manufacturing process, and improving the efficiency of the manufacturing process.

[0078] The above description is only the preferred embodiment of the present application, and any equivalent changes and modifications made according to the claims of the present application shall be within the scope of the present application.

Claims

1. A grinding and inspection system for semiconductor wafers, characterized in that... : The grinding head is equipped with a motor that drives the grinding head to rotate; A retaining ring is fixed to the bottom of the grinding head, wherein the retaining ring includes a plurality of grooves; The grinding pad is located below the grinding head; and A laser sensor is located next to the retaining ring, wherein the laser sensor is used to measure the depth of the plurality of grooves on the retaining ring.

2. The semiconductor wafer grinding and inspection system of claim 1, further comprising a wafer fixed to the bottom of the grinding head and located within the retaining ring.

3. The semiconductor wafer grinding and inspection system as claimed in claim 2, wherein when the wafer is mounted on the grinding head, the bottom surface of the retaining ring is lower than the bottom surface of the wafer.

4. The semiconductor wafer polishing inspection system of claim 2, wherein, viewed from a top view, the retaining ring is an annular structure and is located around the bottom of the polishing head, while the wafer is located at the center of the annular structure.

5. The semiconductor wafer grinding inspection system of claim 1, wherein the laser sensor and the retaining ring are aligned in the initial horizontal direction.

6. The semiconductor wafer grinding and inspection system as claimed in claim 1, further comprising an analysis system connected to the laser sensor, the analysis system further comprising an alarm.

7. A method for inspecting the grinding of semiconductor wafers, characterized in that... : Provides a wafer grinding and inspection system, which includes: The grinding head is equipped with a motor that drives the grinding head to rotate; A retaining ring is fixed to the bottom of the grinding head, wherein the retaining ring includes a plurality of grooves; The first grinding pad is located below the grinding head; and The laser sensor is located next to the retaining ring; The wafer is mounted at the bottom of the grinding head and located within the retaining ring; The laser sensor performs a first measurement step to measure the first depth of the plurality of grooves on the retaining ring; and The wafer is then subjected to the first grinding step.

8. The method for grinding and inspecting a semiconductor wafer as described in claim 7, wherein when the wafer is mounted on the grinding head, the bottom surface of the retaining ring is lower than the bottom surface of the wafer.

9. The grinding and inspection method for semiconductor wafers as claimed in claim 7, wherein before the first grinding step, the retaining ring is in an initial horizontal position, and the laser sensor is aligned with the retaining ring in the initial horizontal direction.

10. The method for grinding and inspecting a semiconductor wafer as claimed in claim 9, wherein during the first grinding step, the grinding head begins to rotate and descends, causing the retaining ring to descend from the initial horizontal position to a first height, so that the wafer is ground on the first grinding pad.

11. The method for inspecting the grinding of a semiconductor wafer as described in claim 10, further comprising: After the first grinding step is completed, the grinding head stops rotating and rises, causing the retaining ring to return to its initial horizontal position.

12. The grinding and inspection method for a semiconductor wafer as claimed in claim 11, wherein when the first grinding step is completed and the retaining ring returns to the initial horizontal position, the laser sensor performs a second measurement step to measure the second depth of the plurality of grooves on the retaining ring.

13. The method for grinding and inspecting semiconductor wafers as claimed in claim 12, further comprising providing an analysis system connected to the laser sensor, the analysis system further comprising an alarm device, wherein the alarm device issues an alarm when the first depth or the second depth of the plurality of grooves on the retaining ring is lower than a set value.

14. The grinding and inspection method for semiconductor wafers as claimed in claim 13, wherein before the first grinding step, the first depth is between 2.5 micrometers and 3.9 micrometers, and the set value is between 2.0 micrometers and 2.5 micrometers.

15. The method for inspecting the grinding of a semiconductor wafer as claimed in claim 12, wherein after the second measurement step is performed, the second grinding pad is moved under the grinding head, and a second grinding step is performed.

16. The method for grinding and inspecting a semiconductor wafer as claimed in claim 7, wherein when the wafer is mounted on the grinding head, the bottom surface of the retaining ring is lower than the bottom surface of the wafer.

17. The method for inspecting the grinding of a semiconductor wafer as claimed in claim 7, wherein, viewed from a top view, the retaining ring is an annular structure and is located around the bottom of the grinding head, while the wafer is located at the center of the annular structure.

18. The method for grinding and inspecting semiconductor wafers as described in claim 7, further comprising a slurry nozzle for spraying slurry onto the first grinding pad.

19. The method for grinding and inspecting a semiconductor wafer as claimed in claim 18, wherein in the first grinding step, the grinding slurry flows from the grooves on the retaining ring to the bottom of the wafer.

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