Substrate polishing method, substrate polishing apparatus, and computer-readable recording medium for recording program

Abstract

This invention relates to a substrate polishing method, which involves pressing polishing tape onto a substrate such as a wafer to polish the substrate. In the substrate polishing method, the actual polishing conditions of previously polished substrates and the actual amount of polishing tape used in the actual polishing conditions are stored in a database (21a), and the actual polishing conditions and actual usage are matched. Before polishing the substrate to be polished, actual polishing conditions that are consistent with the preset polishing conditions of the substrate to be polished are retrieved from the database (21a). The actual amount of polishing tape that is matched with the actual polishing conditions that are consistent with the preset polishing conditions is determined as the predicted amount of polishing tape required for polishing the substrate to be polished. The remaining amount of polishing tape used in polishing the substrate to be polished is compared with the determined predicted amount. When the remaining amount of polishing tape is greater than the predicted amount, the substrate to be polished is polished using polishing modules (4A, 4B).

Description

Technical Field

[0001] This invention relates to a substrate polishing method for polishing substrates such as wafers, and more particularly to a substrate polishing method that polishes a substrate by pressing an polishing tape onto the substrate. Furthermore, this invention relates to a substrate polishing apparatus equipped with a polishing module that presses an polishing tape onto a substrate to polish it. Furthermore, this invention relates to a process for polishing a substrate using an polishing tape. Prior Technology

[0002] From the perspective of improving the manufacturing yield of semiconductor devices, the management of substrate surface condition has received considerable attention in recent years. During the manufacturing process of semiconductor devices, various materials are deposited on silicon wafers. This can lead to the formation of unwanted films or surface roughness at the periphery of the substrate. In recent years, methods have generally been adopted that transport the substrate while holding only the periphery with an arm. However, in this context, the unwanted films remaining at the periphery peel off during various processes and adhere to the devices formed on the substrate, resulting in reduced yield. Therefore, substrate polishing equipment is used to polish the periphery of the substrate to remove the unwanted films formed thereon.

[0003] This type of substrate polishing apparatus polishes the periphery of the substrate by sliding an polishing belt onto it. More specifically, the substrate is held by a substrate holding part and rotated while the polishing head presses the polishing belt against the periphery of the substrate, thereby polishing the periphery. During substrate polishing, the polishing belt is fed from the belt feed reel to the belt take-up reel by the polishing belt supply mechanism through the polishing head. [Previous Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2008-87136 Summary of the Invention

[0005] [The problem the invention aims to solve]

[0006] An end mark is provided near the rear end of the polishing tape wound on the tape feed spool of the polishing tape supply mechanism, and an end mark detection sensor is installed near the tape feed spool to detect the end mark. During the polishing of the substrate periphery, if the end mark detection sensor detects an end mark on the polishing tape, the control unit of the substrate polishing apparatus stops supplying polishing tape to the polishing head from the polishing tape supply mechanism, thus stopping the polishing of the substrate periphery. In other words, the polishing of the substrate periphery is interrupted. Therefore, the error of interrupting substrate polishing due to the detection of an end mark on the polishing tape is sometimes referred to as an "end mark error."

[0007] Substrates whose grinding was interrupted due to incorrect terminal markings are discarded because it is difficult to ascertain the grinding progress at the point of interruption, making it difficult to perform additional grinding. Patent Document 1 describes a processing apparatus that detects the remaining amount of grinding tape from the outer diameter of the grinding tape roll. However, conventional processing apparatuses cannot accurately calculate the actual amount of grinding tape used in grinding, and only determine whether to replace the grinding tape based on the remaining amount. Therefore, sometimes the grinding tape is replaced even when there is still enough grinding tape remaining on the tape reel to grind the next substrate.

[0008] Therefore, the present invention provides a substrate polishing method that, by accurately predicting the amount of polishing tape used in actual polishing, can maximize the consumption of polishing tape and prevent polishing tape terminal errors, thereby reducing the number of waste substrates. Furthermore, the present invention provides a substrate polishing apparatus for polishing substrates using this polishing method. Furthermore, the present invention provides a computer-readable recording medium that records a program for executing this polishing method. [Technical means to solve the problem]

[0009] In one embodiment, a substrate polishing method is provided, which involves storing the actual polishing conditions of at least one previously polished substrate and the actual amount of polishing tape used in the actual polishing conditions in a database, and pairing the actual polishing conditions with the actual amount of usage. Before polishing the substrate to be polished, the method retrieves actual polishing conditions that are consistent with the preset polishing conditions of the substrate to be polished from the database, determines the actual amount of polishing tape used that is paired with the actual polishing conditions that are consistent with the preset polishing conditions as the predicted amount of polishing tape required for polishing the substrate to be polished, compares the remaining amount of polishing tape used in polishing the substrate to the determined predicted amount of usage, and when the remaining amount of polishing tape is greater than or equal to the predicted amount of usage, the polishing module polishes the substrate to be polished. In one case, when determining the aforementioned predicted usage amount, if there are no actual polishing conditions in the aforementioned database that are consistent with the aforementioned preset polishing conditions, the predicted usage amount of the aforementioned polishing tape used in polishing the aforementioned substrate is calculated based on the aforementioned preset polishing conditions and thus determined.

[0010] In one state, the aforementioned actual polishing conditions include a polishing head identification code for identifying the polishing head used in polishing at least one previously polished substrate among a plurality of polishing heads, and the aforementioned preset polishing conditions include a polishing head identification code for identifying the polishing head used in polishing the aforementioned target substrate. In one state, the aforementioned actual polishing conditions include a polishing belt identification code for identifying the type of polishing belt used in polishing at least one previously polished substrate among a variety of polishing belts, and the aforementioned preset polishing conditions include a polishing belt identification code for identifying the type of polishing belt used in polishing the aforementioned substrate to be polished. In one state, the aforementioned actual polishing conditions include the polishing conditions of multiple polishing steps included in the polishing of at least one previously polished substrate, the aforementioned actual usage amount is the actual usage amount of polishing tape used from the start to the end of the polishing process including the aforementioned multiple polishing steps, and the aforementioned preset polishing conditions include the polishing conditions of multiple polishing steps applicable to the polishing of the aforementioned substrate. In one state, in the aforementioned substrate polishing method, a hash value corresponding to the aforementioned actual polishing conditions is generated, and the aforementioned actual usage amount is paired with the aforementioned hash value and stored in the aforementioned database. A retrieval hash value corresponding to the aforementioned preset polishing conditions of the aforementioned substrate to be polished is generated, and a hash value that matches the aforementioned retrieval hash value is retrieved from the aforementioned database. In terms of determining the aforementioned predicted usage amount, the actual usage amount of the aforementioned polishing tape that matches the aforementioned hash value that matches the aforementioned retrieval hash value is determined as the predicted usage amount of polishing tape required to polish the aforementioned substrate to be polished.

[0011] In one embodiment, a substrate polishing apparatus is provided, comprising a polishing module for polishing a substrate with polishing tape and a control system having a database and a computing device. The control system is configured to: store the actual polishing conditions of at least one substrate that has been previously polished and the actual amount of polishing tape used in the actual polishing conditions in the database and pair the actual polishing conditions with the actual amount of polishing tape used; before polishing the substrate to be polished, retrieve actual polishing conditions that are consistent with preset polishing conditions of the substrate to be polished from the database; determine the actual amount of polishing tape used that is paired with the actual polishing conditions that are consistent with the preset polishing conditions as the predicted amount of polishing tape used for polishing the substrate to be polished; compare the remaining amount of polishing tape used in polishing the substrate to be polished with the determined predicted amount of polishing tape used; and when the remaining amount of polishing tape is greater than or equal to the predicted amount of polishing tape used, issue an instruction to the polishing module to polish the substrate to be polished. In one state, the aforementioned control system is configured as follows: when there are no actual polishing conditions in the aforementioned database that are consistent with the aforementioned preset polishing conditions, the predicted amount of polishing tape used in polishing the aforementioned substrate is calculated based on the aforementioned preset polishing conditions.

[0012] In one state, the aforementioned actual polishing conditions include a polishing head identification code for identifying the polishing head used in polishing at least one previously polished substrate among a plurality of polishing heads, and the aforementioned preset polishing conditions include a polishing head identification code for identifying the polishing head used in polishing the aforementioned target substrate. In one state, the aforementioned actual polishing conditions include a polishing belt identification code for identifying the type of polishing belt used in polishing at least one previously polished substrate among a variety of polishing belts, and the aforementioned preset polishing conditions include a polishing belt identification code for identifying the type of polishing belt used in polishing the aforementioned substrate to be polished. In one state, the aforementioned actual polishing conditions include the polishing conditions of multiple polishing steps included in the polishing of at least one previously polished substrate, the aforementioned actual usage amount is the actual usage amount of polishing tape used from the start to the end of the polishing process including the aforementioned multiple polishing steps, and the aforementioned preset polishing conditions include the polishing conditions of multiple polishing steps applicable to the polishing of the aforementioned substrate. In one state, the aforementioned control system is configured as follows: generating a hash value corresponding to the aforementioned actual polishing conditions, pairing the aforementioned actual usage amount with the aforementioned hash value and storing it in the aforementioned database, generating a retrieval hash value corresponding to the aforementioned preset polishing conditions of the aforementioned polishing target substrate, retrieving a hash value consistent with the aforementioned retrieval hash value from the aforementioned database, and determining the actual usage amount of the aforementioned polishing tape paired with the hash value consistent with the aforementioned retrieval hash value as the predicted usage amount of polishing tape required for polishing the aforementioned polishing target substrate.

[0013] In one embodiment, a computer-readable recording medium with a recording program is provided to issue instructions to a control system, causing the computer to perform the following steps: storing the actual polishing conditions of at least one previously polished substrate and the actual amount of polishing tape used in the actual polishing conditions in a database and matching the actual polishing conditions with the actual amount of usage; before polishing the substrate to be polished, retrieving from the database actual polishing conditions that are consistent with the preset polishing conditions of the substrate to be polished; determining the actual amount of polishing tape used that is matched with the actual polishing conditions consistent with the preset polishing conditions as the predicted amount of polishing tape required for polishing the substrate to be polished; comparing the remaining amount of polishing tape used in polishing the substrate to be polished with the determined predicted amount of usage; and when the remaining amount of polishing tape is greater than or equal to the predicted amount of usage, issuing instructions to the polishing module to polish the substrate to be polished. [Comparison with the effectiveness of previous technologies]

[0014] According to the present invention, the predicted amount of grinding tape used is the actual amount of grinding tape paired with the actual grinding conditions that are consistent with the grinding conditions of the substrate to be ground. In this way, the substrate grinding apparatus can determine the correct predicted amount of grinding tape, which reflects the changes in tape feed speed during grinding, the amount of grinding tape feed when the grinding head moves between head positions, and the amount of grinding tape feed between different grinding steps.

[0015] Furthermore, according to the present invention, the substrate polishing apparatus compares the predetermined predicted usage amount with the remaining amount of polishing tape before polishing the substrate to be polished, thereby maximizing the consumption of polishing tape and preventing the occurrence of polishing tape end errors, thereby reducing the number of waste substrates. Simple Explanation of the Diagram

[0016] Figure 1 is a top view of one embodiment of the display substrate polishing apparatus. Figure 2A shows an enlarged cross-sectional view of the periphery of the display substrate. Figure 2B shows an enlarged cross-sectional view of the periphery of the display substrate. Figure 3 is a schematic diagram showing one implementation of the grinding module. Figure 4 is a schematic diagram showing one embodiment of the grinding head. Figure 5 is a top view showing one implementation of the tilting mechanism. Figure 6 shows the state of the continuously polished substrate. Figure 7 shows the state of the substrate being fixed and polished. Figure 8 is a flowchart of one of the implementation methods of the substrate polishing process. Figure 9 is a table showing one example of the grinding conditions for the grinding steps shown in Figure 8. Figure 10 is a flowchart of one implementation of the processing operation of the display substrate polishing apparatus. Figure 11 illustrates the steps of storing the actual polishing conditions and actual usage of polishing tape of previously polished substrates in a database. Figure 12 illustrates the steps of retrieving data from a database and determining the actual polishing conditions that match the preset polishing conditions of the substrate to be polished in order to predict the amount of material to be used. Figure 13 illustrates a method for searching using search hash values. Figure 14 is a top view showing one embodiment of the arrangement of multiple grinding target substrates. Implementation

[0017] The embodiments of the present invention are described below with reference to the drawings. Figure 1 is a top view showing one embodiment of the substrate polishing apparatus. This embodiment of the substrate polishing apparatus is used to polish the peripheral portion of a substrate including a beveled portion. In one embodiment, the substrate polishing apparatus can also be used to polish the notch portion of the substrate. The substrate polishing apparatus includes polishing modules 4A and 4B, standby stages 5A and 5B, a cleaning and drying unit 7, a loading port 10, a first transport robot 16, a second transport robot 17, a third transport robot 18, and a fourth transport robot 19. The polishing modules 4A and 4B, standby stages 5A and 5B, the cleaning and drying unit 7, the first transport robot 16, the second transport robot 17, the third transport robot 18, and the fourth transport robot 19 are disposed within a housing 100.

[0018] The substrate to be ground is stored in substrate cassette 2, which is placed on loading port 10. A first transport robot 16 is disposed adjacent to loading port 10. The first transport robot 16 removes the substrate to be ground from substrate cassette 2 on loading port 10 and transfers it to the second transport robot 17.

[0019] In this embodiment, the substrate polishing apparatus has two polishing modules 4A and 4B. However, in another embodiment, the substrate polishing apparatus may have only one polishing module, or it may have three or more polishing modules. Similarly, in this embodiment, the substrate polishing apparatus has two standby stages 5A and 5B. However, in another embodiment, the substrate polishing apparatus may have only one standby stage, or it may have three or more standby stages.

[0020] Grinding modules 4A and 4B and standby stages 5A and 5B are arranged along the long side of the housing 100. The substrate to be ground is placed on the standby stages 5A and 5B before being ground by the grinding modules 4A and 4B. In one embodiment, the standby stages 5A and / or 5B may also include a notch aligner (not shown). The notch aligner is a device used to detect the notch (groove) of the substrate and align the notch of the substrate to a predetermined position. The specific configuration of the notch aligner is not particularly limited as long as it can detect the notch of the substrate and align the notch of the substrate to a predetermined position.

[0021] The peripheral portion of the substrate to be polished is polished by at least one of polishing modules 4A and 4B. The peripheral portion of the substrate to be polished may be polished by only one polishing module 4A or 4B, or it may be polished by two polishing modules 4A and 4B.

[0022] Polishing module 4A has two polishing heads 33A and 33B. Polishing of the substrate by polishing module 4A can be performed using only one polishing head 33A or 33B, or it can be performed using both polishing heads 33A and 33B. Polishing module 4B has two polishing heads 33C and 33D. Polishing of the substrate by polishing module 4B can be performed using only one polishing head 33C or 33D, or it can be performed using both polishing heads 33C and 33D.

[0023] The second transport robot 17 is arranged adjacent to the grinding modules 4A and 4B, the standby stages 5A and 5B, and the cleaning and drying unit 7. The second transport robot 17 transports substrates received from the first transport robot 16, performing substrate pickup and drop between the grinding modules 4A and 4B and the standby stages 5A and 5B. Furthermore, the second transport robot 17 transfers the substrates received from the grinding modules 4A and 4B to the cleaning and drying unit 7.

[0024] The cleaning and drying unit 7 includes a first cleaning module 12 and a second cleaning module 13 for cleaning the substrate after the peripheral portions of the substrate have been polished by the polishing modules 4A and 4B, and a drying module 14 for drying the cleaned substrate. The first cleaning module 12, the second cleaning module 13, and the drying module 14 are arranged along the long side of the housing 100. The first cleaning module 12 is configured to perform brushing with a roller-shaped sponge member. The second cleaning module 13 is configured to perform brushing with a pencil-shaped sponge member. In this embodiment, the cleaning and drying unit 7 includes the first cleaning module 12 and the second cleaning module 13. In another embodiment, the cleaning and drying unit 7 may also include either the first cleaning module 12 or the second cleaning module 13.

[0025] A third transport robot 18 is positioned between the first cleaning module 12 and the second cleaning module 13. A fourth transport robot 19 is positioned between the second cleaning module 13 and the drying module 14. The third transport robot 18 performs substrate transport between the first cleaning module 12 and the second cleaning module 13. The fourth transport robot 19 performs substrate transport between the second cleaning module 13 and the drying module 14.

[0026] In the substrate polishing apparatus, multiple substrates are polished in sequence by polishing modules 4A and / or 4B, and the substrates are cleaned and dried by cleaning and drying unit 7, thereby polishing multiple substrates.

[0027] The substrate polishing apparatus further includes a control system 20, which is electrically connected to polishing modules 4A and 4B, standby stages 5A and 5B, cleaning and drying unit 7, first transport robot 16, second transport robot 17, third transport robot 18, and fourth transport robot 19. The control system 20 controls the operation of polishing modules 4A and 4B, standby stages 5A and 5B, cleaning and drying unit 7, first transport robot 16, second transport robot 17, third transport robot 18, and fourth transport robot 19.

[0028] The control system 20 includes a storage device 21 for storing the database 21a and the program (described later), and a computing device 22 for executing calculations according to the program. The storage device 21 includes a main storage device (e.g., random access memory) accessible by the computing device 22 and an auxiliary storage device (e.g., a hard disk drive or solid-state drive) for storing the database 21a and the program. The computing device 22 includes a CPU (central processing unit) or GPU (graphics processing unit) that performs calculations according to the instructions contained in the program stored in the storage device 21.

[0029] In one embodiment, the control system 20 may also have a display screen (not shown in the figure) for displaying the processing results and processed data from the computing device 22, and an input device (not shown in the figure) for inputting data, programs and various information into the storage device 21.

[0030] The control system 20 includes at least one computer. For example, the control system 20 may be an edge server connected to the substrate polishing apparatus via a communication line, or a cloud server connected to the substrate polishing apparatus via a network such as the Internet. The control system 20 may be a combination of multiple servers. For example, the control system 20 may be a combination of edge servers and cloud servers interconnected via communication networks such as the Internet or a local area network, or it may be a combination of multiple servers not connected by a communication network. However, the specific configuration of the control system 20 is not limited to these examples. In one embodiment, the control system 20 is composed of various devices, and may also include a storage device 21 and a computing device 22.

[0031] Next, the detailed configuration of polishing modules 4A and 4B will be explained. Polishing modules 4A and 4B have essentially the same configuration, therefore, polishing module 4A will be described below. In this embodiment, polishing module 4A is configured to polish the peripheral portion of the polishing substrate W shown in Figures 2A and 2B. Figures 2A and 2B are enlarged cross-sectional views showing the peripheral portion of the substrate W. More specifically, Figure 2A is a cross-sectional view of a so-called straight substrate, and Figure 2B is a cross-sectional view of a so-called rounded substrate. The straight portion B has a chamfered shape or a rounded shape.

[0032] In the substrate W of Figure 2A, the beveled portion B is the outermost peripheral surface of the substrate W, formed by the upper beveled surface (upper beveled portion) B1, the lower beveled surface (lower beveled portion) B2, and the side portion (top) B3. In the substrate W of Figure 2B, the beveled portion B is the portion that forms the outermost peripheral surface of the substrate W and has a curved cross-section. The top edge portion E1 is an annular flat portion located radially inward of the beveled portion B. The bottom edge portion E2 is located on the opposite side of the top edge portion E1, and is an annular flat portion located radially inward of the beveled portion B. The top edge portion E1 may also include an area where components are formed. In this specification, the peripheral portion of the substrate W refers to the area that includes any one of the top edge portion E1, the beveled portion B, and the bottom edge portion E2.

[0033] Figure 3 is a schematic diagram showing one embodiment of the polishing module 4A. The polishing module 4A includes: a substrate holding part 40 for holding and rotating the substrate W to be polished; two polishing heads 33A and 33B for pressing polishing belts 32A and 32B onto the periphery of the substrate W, which is rotated by the substrate holding part 40, to polish the periphery of the substrate W; a lower supply nozzle 42 for supplying liquid to the lower surface of the substrate W; and an upper supply nozzle 43 for supplying liquid to the upper surface of the substrate W. Pure water can be cited as an example of the liquid supplied to the substrate W. During the polishing of the substrate W, liquid is supplied to the lower surface of the substrate W from the lower supply nozzle 42 and to the upper surface of the substrate W from the upper supply nozzle 43.

[0034] In this embodiment, the polishing module 4A has two polishing heads 33A and 33B. However, in another embodiment, the polishing module 4A may have only one polishing head, or it may have three or more polishing heads. The substrate W to be polished is polished by at least one of the polishing heads 33A and 33B of the polishing module 4A. When polishing head 33A is in the polishing position, polishing head 33B is in the avoidance position. When polishing head 33B is in the polishing position, polishing head 33A is in the avoidance position.

[0035] Figure 3 shows the state where the grinding head 33A is positioned in the grinding position and the grinding head 33B is positioned in the avoidance position. The grinding head 33A faces the periphery of the substrate W. The substrate holding part 40 holds the substrate W. The substrate holding part 40 includes a holding stage 34 that holds the substrate W by vacuum adsorption, a shaft 35 connected to the center of the holding stage 34, and a holding stage drive mechanism 37 that rotates the holding stage 34 and moves it up and down. The holding stage drive mechanism 37 is configured to allow the holding stage 34 to rotate around its axis Cr and move along the axis Cr in the up and down direction.

[0036] The substrate W is placed on the substrate holding surface of the holding stage 34 by the second transport robot 17 (see Figure 1) with the center O1 of the substrate W located on the axis Cr of the holding stage 34. The substrate holding part 40 is capable of rotating the substrate W about the axis Cr of the holding stage 34 (that is, the axis of the substrate W) and moving the substrate W up and down along the axis Cr of the holding stage 34.

[0037] The grinding module 4A includes a grinding belt supply mechanism 46A, which supplies the grinding belt 32A to the grinding head 33A and recovers it from the grinding head 33A. The grinding module 4A further includes a grinding belt supply mechanism 46B, which supplies the grinding belt 32B to the grinding head 33B and recovers it from the grinding head 33B. The grinding belt supply mechanisms 46A and 46B have essentially the same configuration; therefore, the grinding belt supply mechanism 46A will be described below.

[0038] The polishing belt supply mechanism 46A includes: a belt feed reel 47 for supplying the polishing belt 32A to the polishing head 33A; and a belt take-up reel 48 for recovering the polishing belt 32A used for polishing the substrate W. The belt feed reel 47 and the belt take-up reel 48 are respectively connected to tension motors (not shown in the figure). Each tension motor applies a predetermined torque to the belt feed reel 47 and the belt take-up reel 48, thereby applying a predetermined tension to the polishing belt 32A.

[0039] The polishing belt 32A is supplied to the polishing head 33A with its polishing surface facing the periphery of the substrate W. The polishing belt 32A is supplied to the polishing head 33A from the belt feed reel 47, and the used polishing belt 32A is retrieved by the belt take-up reel 48. The polishing belt supply mechanism 46A further includes multiple guide rollers 50, 51, 52, and 53 for supporting the polishing belt 32A. The travel direction of the polishing belt 32A is guided by the guide rollers 50, 51, 52, and 53.

[0040] Next, the details of the structure of grinding heads 33A and 33B will be explained. Grinding heads 33A and 33B have essentially the same structure, so grinding head 33A will be described below. The structures of grinding heads 33C and 33D of grinding module 4B are also essentially the same as those of grinding head 33A described below, so their repeated description is omitted. Figure 4 is a schematic diagram showing one embodiment of grinding head 33A. Grinding head 33A is equipped with a belt feed device 56, which feeds the grinding belt 32A from the belt feed reel 47 (see Figure 3) toward the belt take-up reel 48 (see Figure 3). Grinding head 33A has a plurality of guide rollers 60, 61, 62, 63, 64, 65, and 66, which guide the grinding belt 32A so that the grinding belt 32A travels in a direction orthogonal to the tangential direction of the substrate W.

[0041] The belt feed device 56, located on the grinding head 33A, includes a belt feed roller 56a, a belt support roller 56b, and a belt feed motor M that rotates the belt feed roller 56a. The belt feed motor M is located on the side of the grinding head 33A, and the belt feed roller 56a is mounted on the rotation shaft of the belt feed motor M. The belt support roller 56b is arranged adjacent to the belt feed roller 56a. The belt support roller 56b is supported by a mechanism not shown in the figure and applies force in the direction indicated by the arrow NF in Figure 4 (towards the belt feed roller 56a), thus pressing the belt feed roller 56a.

[0042] If the belt feed motor M rotates in the direction indicated by arrow R in Figure 4, the belt feed roller 56a rotates, causing the grinding belt 32A to be fed along its long side. The belt carrier roller 56b is configured to rotate around its axis, rotating due to the feeding of the grinding belt 32A. The belt feed motor M has a rotary encoder (not shown in the figure) to calculate the number of rotations of the belt feed motor M.

[0043] The grinding head 33A further includes: a pressing member 68 for pressing the grinding belt 32A onto the substrate W; and a cylinder 54, which acts as an actuator to move the pressing member 68 toward the periphery of the substrate W. The pressing force of the grinding belt 32A onto the substrate W is adjusted by controlling the air pressure supplied to the cylinder 54. The pressing member 68 is disposed on the back side of the grinding surface 32p (the surface with abrasive grains) of the grinding belt 32A. When the pressing member 68 moves toward the substrate W due to the cylinder 54, the pressing member 68 presses the grinding belt 32A onto the periphery of the substrate W from its back side. In this way, the grinding head 33A grinds the periphery of the substrate W.

[0044] Figure 5 is a top view showing one embodiment of the tilting mechanisms 70A and 70B that tilt the grinding heads 33A and 33B. As shown in Figure 5, the grinding module 4A further includes two tilting mechanisms 70A and 70B, which tilt the grinding heads 33A and 33B at a predetermined angle. The tilting mechanism 70A is connected to the grinding head 33A, and the tilting mechanism 70B is connected to the grinding head 33B. The tilting mechanism 70A that tilts the grinding head 33A and the tilting mechanism 70B that tilts the grinding head 33B have essentially the same configuration, so the tilting mechanism 70A will be described below.

[0045] The tilting mechanism 70A is configured to tilt the grinding head 33A relative to the substrate holding surface of the holding stage 34. More specifically, the tilting mechanism 70A includes: a crank arm 72 connected to the grinding head 33A; and an arm rotation device 73 for rotating the crank arm 72. One end of the crank arm 72 is substantially at the same height as the substrate holding surface of the holding stage 34 and is connected to the arm rotation device 73. The other end of the crank arm 72 is connected to the grinding head 33A.

[0046] If the arm rotating device 73 rotates the crank arm 72, the grinding head 33A can be tilted relative to the substrate W on the substrate holding surface of the holding stage 34 at a predetermined tilting speed. Therefore, the grinding head 33A can grind the periphery of the substrate W while tilting at a predetermined tilting speed. The tilting speed is the angle at which the grinding head tilts per unit time. For example, the unit of tilting speed is expressed in "degrees per minute". Furthermore, the tilting mechanism 70A is configured to maintain the grinding head 33A at a predetermined tilting angle. Therefore, the grinding head 33A can grind the periphery of the substrate W while maintaining a predetermined tilting angle. In addition, as long as the grinding head 33A can be tilted relative to the substrate holding surface of the holding stage 34 and the substrate W, the specific configuration of the tilting mechanism 70A is not limited to the embodiment shown in FIG. 5.

[0047] The polishing module 4A is electrically connected to the control system 20, which controls the operation of each component of the polishing module 4A. The polishing heads 33A and 33B, the substrate holding part 40, the lower supply nozzle 42, the upper supply nozzle 43, the polishing belt supply mechanisms 46A and 46B, and the tilting mechanisms 70A and 70B are electrically connected to the control system 20. The operation of the polishing heads 33A and 33B, the substrate holding part 40, the lower supply nozzle 42, the upper supply nozzle 43, the polishing belt supply mechanisms 46A and 46B, and the tilting mechanisms 70A and 70B is controlled by the control system 20.

[0048] Grinding modules 4A and 4B perform two grinding modes for the peripheral area of ​​the substrate, depending on the movement of the grinding head during grinding: continuous grinding and fixed grinding. In this specification, the grinding mode in which "the grinding head is continuously tilted at a predetermined tilting speed while grinding the peripheral area of ​​the substrate" is referred to as "continuous grinding." The grinding mode in which the grinding head is kept at a predetermined tilting angle while grinding the peripheral area of ​​the substrate is referred to as "fixed grinding."

[0049] Figure 6 shows the continuous grinding of the peripheral portion of the substrate W by the grinding head 33A of the grinding module 4A. During continuous grinding, the tilt angle of the grinding head 33A is continuously changed by the tilting mechanism 70A (see Figure 5), while the grinding head 33A presses the grinding tape 32A onto the peripheral portion of the substrate W. More specifically, as shown in Figure 6, the tilting mechanism 70A continuously changes the tilt angle of the grinding head 33A from a head position G1 with a tilt angle of α1 (e.g., 60 degrees) to a head position G2 with a tilt angle of α2 (e.g., -60 degrees) at a predetermined tilting speed. During the tilting of the grinding head 33A by the tilting mechanism 70A, the pressing member 68 of the grinding head 33A presses the grinding tape 32A onto the peripheral portion of the substrate W by the cylinder 54. In this way, the grinding head 33A grinds the peripheral portion of the substrate W. The tilting mechanism 70A causes the polishing head 33A to move back and forth between head position G1 and head position G2 with a predetermined number of tilting movements. During the polishing of the substrate W, the polishing belt 32A is fed at a predetermined speed by the belt feed device 56 (see Figure 4).

[0050] Figure 7 shows the state in which the peripheral portion of the substrate W is fixedly polished by the polishing head 33A of the polishing module 4A. In the fixed polishing example shown in Figure 7, the polishing head 33A is sequentially maintained at a predetermined number of tilt angles by the tilting mechanism 70A shown in Figure 5, and the polishing tape 32A is pressed onto the peripheral portion of the substrate W by the polishing head 33A. More specifically, as shown in Figure 7, the tilting mechanism 70A maintains the polishing head 33A at a head position G1 with a tilt angle of α1 (e.g., 60 degrees) for a predetermined polishing time. Then, the tilting mechanism 70A moves the polishing head 33A from the head position G1 to the head position G2 with a tilt angle of α2 (e.g., 30 degrees) at a predetermined tilting speed, and maintains the polishing head 33A at the head position G2 for a predetermined polishing time. Next, the tilting mechanism 70A moves the grinding head 33A from head position G2 to head position G3 with a tilt angle of α3 (e.g., -30 degrees) at a predetermined tilting speed, and maintains the grinding head 33A in head position G3 for a predetermined grinding time. Then, the tilting mechanism 70A moves the grinding head 33A from head position G3 to head position G4 with a tilt angle of α4 (e.g., -60 degrees) at a predetermined tilting speed, and maintains the grinding head 33A in head position G4 for a predetermined grinding time.

[0051] During the movement of the polishing head 33A between head positions, the polishing belt 32A leaves the substrate W. After the polishing head 33A is positioned at a predetermined head position, it presses the polishing belt 32A onto the substrate W, polishing the periphery of the substrate W. During the polishing of the substrate W and during the movement of the polishing head 33A between head positions, the polishing belt 32A is fed at a predetermined speed by the belt feed device 56 (see Figure 4). In one embodiment, the polishing head 33A can also press the polishing belt 32A onto the substrate W and polish the periphery of the substrate W while moving between head positions.

[0052] In this embodiment, the head position of the grinding head 33A is one of four positions, from head position G1 to head position G4. However, in another embodiment, the head position of the grinding head 33A may be three or fewer or five or more.

[0053] The substrate polishing apparatus of this embodiment can also supply different types of polishing tapes to polishing heads 33A and 33B of polishing module 4A and polishing heads 33C and 33D of polishing module 4B for polishing. For example, the polishing head 33A of polishing module 4A can be used to perform rough polishing on the entire peripheral portion of substrate W, including the top edge portion E1, the beveled portion B, and the bottom edge portion E2 (see Figures 2A and 2B), and then the polishing head 33B can be used to perform fine polishing on the entire peripheral portion of substrate W, including the top edge portion E1, the beveled portion B, and the bottom edge portion E2. In this case, the polishing tape for rough polishing (i.e., the polishing tape with large abrasive grains) is supplied to polishing head 33A from polishing tape supply mechanism 46A, and the polishing tape for fine polishing (i.e., the polishing tape with small abrasive grains) is supplied to polishing head 33B from polishing tape supply mechanism 46B. Alternatively, the grinding head 33A of the grinding module 4A can be used to perform rough grinding on the periphery of the substrate W, which includes the top edge E1, the beveled part B and the bottom edge E2. Then, the grinding head 33B can be used to perform fine grinding on the top edge E1. After that, the grinding head 33C of the grinding module 4B can be used to perform fine grinding on the beveled part B. Finally, the grinding head 33D can be used to perform fine grinding on the bottom edge E2.

[0054] The polishing of the periphery of substrate W is performed using preset polishing conditions. These preset polishing conditions are, for example, input by the user into the control system 20 via an input device (not shown in the figure) and then stored in the storage device 21 of the control system 20. The control system 20 controls the operation of polishing module 4A (and / or polishing module 4B) according to the polishing conditions stored in the storage device 21, causing polishing module 4A (and / or polishing module 4B) to perform polishing of the periphery of substrate W.

[0055] Figure 8 is a flowchart illustrating one embodiment of the polishing steps for substrate W. In this embodiment, the polishing of substrate W includes four polishing steps: a first polishing step, a second polishing step, a third polishing step, and a fourth polishing step. First, in the first polishing step, substrate W is continuously polished using polishing head 33A of polishing module 4A. Then, in the second polishing step, substrate W is fixedly polished using the same polishing head 33A. Next, substrate W is continuously polished using polishing head 33C of polishing module 4B. Finally, substrate W is fixedly polished using polishing head 33D of polishing module 4B. As with the first and second polishing steps, one polishing head 33A can also be used to perform continuous polishing and fixed polishing with different polishing modes on one substrate. In one embodiment, the polishing of substrate W may also include only a single polishing step.

[0056] Figure 9 is a table showing an example of the grinding conditions for the grinding steps shown in Figure 8. The grinding conditions in this embodiment include the formula name, formula update date and time, grinding module identification code, grinding head identification code, grinding belt identification code, grinding mode, belt feed speed, tilting speed, number of tilts, tilt angles α1~α4 for each head position, and grinding time T1~T4 for each head position. The parameters shown in Figure 9 are an example of grinding conditions; however, the grinding conditions are not limited to these as long as they include the parameters required for the motion control of grinding modules 4A and 4B.

[0057] The formula name is the name (e.g., a string of words) of the grinding formula created by the user, serving as an identifier for specific grinding conditions. The grinding formula contains a combination of grinding condition parameter values ​​from all grinding steps performed by grinding modules 4A and 4B. The formula name is pre-paired with each parameter value of the grinding conditions, allowing for unambiguous identification of each parameter value based on the formula name. In the embodiment shown in Figure 9, the grinding formula represented by the formula name "ABC" includes the parameter values ​​contained in the grinding conditions of grinding steps 1 through 4.

[0058] The formula update date and time refer to the date and time when the parameter values ​​of the grinding conditions paired with the formula name are updated. When a new formula name and grinding conditions are registered in the control system 20, or when the parameter values ​​of the grinding conditions paired with an already registered formula name are changed, the control system 20 will automatically register (record) the formula update date and time.

[0059] The grinding module identification code is a value (numerical, textual, or a combination thereof) used to identify the grinding module used in each grinding step. In one example, the grinding module identification code is "4A" or "4B".

[0060] The grinding head identification code is a value (numerical, textual, or a combination thereof) used to identify the grinding head used in each grinding step. In one example, the grinding head identification codes are "33A", "33B", "33C", and "33D".

[0061] The abrasive belt identification code is a value (numerical, literal, or a combination thereof) used to identify the type of abrasive belt used in each abrasive step. Abrasive belts come in various types depending on the roughness of the abrasive grains on the abrasive surface and the width of the abrasive belt. In one example, the abrasive belt identification codes are "32A", "32B", "32C", and "32D".

[0062] The grinding mode is used to specify the value (numerical, textual, or a combination thereof) of the grinding mode applied in each grinding step. In the embodiment shown in Figure 9, the grinding mode of the first grinding step is "continuous grinding", the grinding mode of the second grinding step is "fixed grinding", the grinding mode of the third grinding step is "continuous grinding", and the grinding mode of the fourth grinding step is "fixed grinding".

[0063] The feed rate is a set value for the feed rate of each grinding belt in each grinding step. In the embodiment shown in Figure 9, the grinding belt feed rate is "50 mm / min".

[0064] The tilting speed is the set value of the tilting speed of each grinding head in each grinding step. In the embodiment shown in Figure 9, the tilting speed is "2000 degrees / minute".

[0065] The tilting number is a set value for the number of times the grinding head tilts when the grinding mode is continuous grinding. In the embodiment shown in Figure 9, the tilting number in the first grinding step and the third grinding step (continuous grinding) is "5 times". That is, as shown in Figure 6, the grinding head moves back and forth 5 times between head position G1 and head position G2.

[0066] The tilt angles α1 to α4 of the head positions G1 to G4 are set values ​​for the tilt angle of the grinding head at each head position. In the embodiment shown in Figure 9, the tilt angle α1 of the head position G1 in the first grinding step and the third grinding step (continuous grinding) is "60 degrees", and the tilt angle α2 of the head position G2 is "-60 degrees". That is, in the continuous grinding shown in Figure 6, the tilt angle α1 of the head position G1 is 60 degrees, and the tilt angle α2 of the head position G2 is -60 degrees. In the second grinding step and the fourth grinding step (fixed grinding), the tilt angle α1 of the head position G1 is "60 degrees", the tilt angle α2 of the head position G2 is "30 degrees", the tilt angle α3 of the head position G3 is "-30 degrees", and the tilt angle α4 of the head position G4 is "-60 degrees". That is, in the fixed grinding shown in Figure 7, the tilt angle α1 of head position G1 is 60 degrees, the tilt angle α2 of head position G2 is 30 degrees, the tilt angle α3 of head position G3 is -30 degrees, and the tilt angle α4 of head position G4 is -60 degrees.

[0067] The grinding times T1 to T4 for head positions G1 to G4 are set values ​​for the grinding time at each head position when the grinding mode is fixed grinding. In the embodiment shown in Figure 9, the grinding times T1 to T4 for head positions G1 to G4 in the second grinding step and the fourth grinding step (fixed grinding) are each "2 seconds". That is, in the fixed grinding shown in Figure 7, grinding heads 33A and 33D are maintained in head positions G1 to G4 for 2 seconds each.

[0068] The control system 20 controls the operation of the grinding modules 4A and 4B according to the parameter values ​​included in the preset grinding conditions, and performs grinding on the periphery of the substrate.

[0069] Next, the processing operation of the substrate polishing apparatus shown in Figure 1 will be explained. The processing operation of the substrate polishing apparatus described below includes the polishing operation of the peripheral portion of the substrate in the polishing modules 4A and 4B, which is controlled by the control system 20 shown in Figure 1.

[0070] Figure 10 is a flowchart illustrating one embodiment of the processing operation of the substrate polishing apparatus. The control system 20 stores the actual polishing conditions and actual usage of substrates previously polished by polishing modules 4A and 4B in database 21a (see Figure 1) and pairs the actual polishing conditions and actual usage (step 1). In this specification, the polishing conditions previously used by polishing modules 4A and 4B for polishing substrates are referred to as "actual polishing conditions." The actual amount of polishing tape consumed under the actual polishing conditions of previously polished substrates is referred to as "actual usage." Each time a polishing formula is executed, the actual polishing conditions and actual usage are stored in database 21a. Since at least one substrate has been previously polished, and multiple substrates have been previously polished, database 21a stores multiple actual polishing conditions and multiple actual usage amounts.

[0071] Before polishing the substrate to be polished, the control system 20 retrieves actual polishing conditions that match the preset polishing conditions of the substrate to be polished from the database 21a (step 2). When a polishing condition that matches the preset polishing conditions of the substrate to be polished exists in the database 21a ("Yes" in step 3), the control system 20 determines the actual usage amount that matches the actual polishing condition that matches the preset polishing conditions as the predicted usage amount of polishing tape used in polishing the substrate to be polished (step 4).

[0072] When the actual polishing conditions that match the preset polishing conditions of the substrate to be polished are not found in the database 21a (No in step 3), the control system 20 calculates the predicted amount of polishing tape used in polishing the substrate to be polished by the method described later, and determines the predicted amount of usage (step 5).

[0073] The control system 20 compares the remaining amount of polishing tape used in polishing the substrate with the predicted usage amount determined in step 4 or step 5 (step 6). If the remaining amount of polishing tape is greater than the predicted usage amount ("Yes" in step 6), the control system 20 issues a command to polishing module 4A or polishing module 4B to perform polishing of the substrate under the aforementioned preset polishing conditions (step 7). The control system 20 can also store the actual polishing conditions and actual usage amount during polishing of the substrate in database 21a after polishing the substrate (step 1).

[0074] When the remaining amount of polishing tape used in polishing the substrate is less than the predicted usage ("No" in step 6), the control system 20 issues a tape depletion alarm, urging the user to replace the polishing tape (step 8). The user replaces the polishing tape (step 9). After the tape depletion state is cleared, the control system 20 issues a command to polishing module 4A or polishing module 4B to perform polishing of the substrate under the aforementioned preset polishing conditions (step 7). The control system 20 can also store the actual polishing conditions and actual usage of the substrate in database 21a after polishing (step 1).

[0075] The control system 20 operates according to commands contained in a program stored electronically in the storage device 21 (see Figure 1). That is, the control system 20 performs the following steps: storing the actual polishing conditions of at least one substrate that has been previously polished and the actual amount of polishing tape used in the actual polishing conditions in the database 21a and matching the actual polishing conditions with the actual amount used (see step 1 above); retrieving actual polishing conditions that match the preset polishing conditions of the substrate before polishing the substrate (see step 2 above); determining the actual amount of polishing tape used that matches the actual polishing conditions that match the preset polishing conditions as the predicted amount of polishing tape needed to polish the substrate (see step 4 above); comparing the remaining amount of polishing tape used in polishing the substrate with the determined predicted amount of use (see step 6 above); and issuing a command to the polishing module 4A or the polishing module 4B when the remaining amount of polishing tape is greater than or equal to the predicted amount of use, and polishing the substrate with the preset polishing conditions (see step 7 above).

[0076] When the control system 20 does not have actual polishing conditions that match the preset polishing conditions in the database 21a, it performs a step of calculating and determining the predicted amount of polishing tape to be used based on the preset polishing conditions (refer to step 5 above). Furthermore, the control system 20 performs the following steps: issuing a tape depletion alarm to urge the user to replace the polishing tape when the remaining amount of polishing tape is less than the predicted amount to be used in polishing the substrate (refer to step 8 above); and issuing a command to polishing module 4A or polishing module 4B to polish the substrate under the preset polishing conditions after the tape depletion state is resolved (refer to step 7 above).

[0077] The program used to cause the control system 20 to perform these steps is recorded on a computer-readable recording medium that is a non-transient tangible object and provided to the control system 20 through the recording medium. Alternatively, the program can also be input into the control system 20 through communication networks such as the Internet or a local area network.

[0078] The feed speed of the polishing belt during substrate polishing is not actually fixed. In continuous polishing, the feed speed can vary due to friction caused by the tilting of the polishing head. Furthermore, in stationary polishing, the polishing belt feeds as the polishing head moves between positions, and the feed amount varies depending on the distance the head moves between positions. Moreover, the polishing belt also feeds during the transition between continuous and stationary polishing. Therefore, conventional techniques have struggled to accurately calculate the predicted amount of polishing belt used.

[0079] Therefore, in this embodiment of the substrate polishing apparatus, the actual amount of polishing tape used, which matches the actual polishing conditions of the substrate to be polished, is used as the predicted amount of polishing tape to be used. In this way, the substrate polishing apparatus can determine the correct predicted amount of use, which reflects the changes in tape feed speed during polishing, the amount of tape feed when the polishing head moves between head positions, and the amount of tape feed between different polishing steps. Furthermore, before polishing the substrate to be polished, the substrate polishing apparatus compares the remaining amount of polishing tape with the determined predicted amount of use, thereby maximizing the consumption of polishing tape, preventing errors in tape termination, and reducing the number of discarded substrates.

[0080] Next, the details of each of the above processing actions will be explained. Figure 11 illustrates the steps of storing the actual polishing conditions AP1, AP2, AP3 and the actual usage amounts AU1, AU2, AU3 of the previously polished substrates W1, W2, W3 in database 21a (refer to step 1 in Figure 10). As shown in Figure 11, when the polishing of substrate W1 is completed, the control system 20 stores the actual polishing conditions AP1 and the actual usage amount AU1 of the polishing tape in database 21a. For example, as described with reference to Figure 8, if the polishing of substrate W1 includes polishing steps 1 to 4, the actual polishing conditions AP1 and the actual usage amounts AU1 of polishing tapes 32A, 32C, 32D are stored in database 21a only at the end of the 4th polishing step.

[0081] The actual polishing conditions AP1 for polishing substrate W1 include the polishing conditions for polishing steps 1 to 4. The actual polishing conditions, as illustrated with reference to FIG9, include at least one of the following: formula name, formula update date and time, polishing module identification code, polishing head identification code, polishing belt identification code, polishing mode, belt feed speed, tilting speed, number of tilts, tilting angles α1 to α4 at each head position, and polishing time T1 to T4 at each head position.

[0082] The actual amount of polishing tape used is calculated for each polishing head used in the substrate polishing process. That is, the amount of polishing tape 32A actually used by polishing head 33A in the first and second polishing steps, the amount of polishing tape 32C actually used by polishing head 33C in the third polishing step, and the amount of polishing tape 32D actually used by polishing head 33D in the fourth polishing step are calculated.

[0083] The rotary encoder (not shown) installed in the feed motor M (see Figure 4) of the grinding heads 33A-33D constitutes a system for calculating the number of rotations of the feed motor M. The control system 20 calculates the actual usage of the grinding belts 32A-33D from the number of rotations of the feed motor M of the grinding heads 33A-33D and the outer circumference length of the feed roller 56a (see Figure 4). For example, if the feed motor M of the grinding head 33A rotates 5.7 times between the first and second grinding steps, the control system 20 multiplies the outer circumference length of the feed roller 56a by 5.7 to calculate the actual usage of the grinding belt 32A.

[0084] Similarly, if the polishing of substrate W2 is completed, the control system 20 stores the actual polishing conditions AP2 and the actual amount of polishing tape used AU2 in the database 21a. Furthermore, if the polishing of substrate W3 is completed, the control system 20 stores the actual polishing conditions AP3 and the actual amount of polishing tape used AU3 in the database 21a. When storing the actual polishing conditions and actual usage in the database 21a, the control system 20 displays the login date and time of storing the actual polishing conditions and actual usage, matching them together with the actual polishing conditions and actual usage.

[0085] The control system 20 can also generate hash values ​​HV1, HV2, and HV3 corresponding to the actual polishing conditions AP1, AP2, and AP3 respectively via the computing device 22 (see Figure 1), and store the actual polishing conditions AP1, AP2, and AP3 and the generated hash values ​​HV1, HV2, and HV3 in the database 21a respectively. The hash value is an identification code generated based on the parameter values ​​of each actual polishing condition and by an algorithm contained in the program stored in the storage device 21 (see Figure 1). The hash value is composed of numerical values, text, or combinations thereof, and unambiguously corresponds to a combination of multiple parameter values ​​of each actual polishing condition. By using the hash value, the control system 20 can speed up the processing of retrieving actual polishing conditions from the database 21a that match the polishing conditions of the substrate to be polished.

[0086] In one implementation, when the actual grinding conditions include grinding steps performed by multiple grinding heads, the control system 20 can also generate a hash value corresponding to the actual grinding conditions for each grinding head. The multiple hash values ​​generated for each grinding head are then paired with the multiple grinding heads. Furthermore, the control system 20 can also pair the actual amount of grinding tape used, calculated for each grinding head, with the hash values ​​generated for each grinding head and store them in the database 21a.

[0087] For example, referring to FIG8, when the actual polishing conditions AP1 of the substrate W1 include the polishing conditions of polishing steps 1 to 4, the same number of hash values ​​as the number of polishing heads are generated for each of polishing heads 33A, 33C, and 33D. More specifically, the control system 20 generates three hash values, which are the hash value paired with polishing head 33A corresponding to the actual polishing conditions of polishing steps 1 and 2, the hash value paired with polishing head 33C corresponding to the actual polishing conditions of polishing step 3, and the hash value paired with polishing head 33D corresponding to the actual polishing conditions of polishing step 4.

[0088] Furthermore, the control system 20 pairs and stores the actual usage of the grinding belt 32A of the grinding head 33A with the hash value paired with the grinding head 33A in the database 21a, pairs and stores the actual usage of the grinding belt 32C of the grinding head 33C with the hash value paired with the grinding head 33C in the database 21a, and pairs and stores the actual usage of the grinding belt 32D of the grinding head 33D with the hash value paired with the grinding head 33C in the database 21a.

[0089] Thus, the control system 20 stores the actual polishing conditions, the actual amount of polishing tape used, and the hash value in the database 21a at the end of all polishing steps on a substrate each time. The storage device 21 constructs the database 21a based on the actual polishing conditions, actual amount of polishing tape used, and hash value data of previously polished substrates. The computing device 22 can read the actual polishing conditions, actual amount used, and hash value stored in the database 21a.

[0090] Figure 12 illustrates the steps of retrieving actual polishing conditions from database 21a that match the preset polishing conditions of the substrate to be polished and determining the predicted usage amount (refer to steps 2 to 4 in Figure 10). Database 21a, as shown in Figure 12, stores data including the actual polishing conditions AP1, actual usage amount AU1, and hash value HV1 of a previously polished substrate W1; the actual polishing conditions AP2, actual usage amount AU2, and hash value HV2 of a previously polished substrate W2; and the actual polishing conditions AP3, actual usage amount AU3, and hash value HV3 of a previously polished substrate W3.

[0091] Before grinding the substrate to be ground, the control system 20 retrieves actual grinding conditions from the database 21a that match the preset grinding conditions of the substrate to be ground. The preset grinding conditions of the substrate to be ground, as described with reference to FIG9, include at least one of the following: formula name, formula update date and time, grinding module identification code, grinding head identification code, grinding belt identification code, grinding mode, belt feed speed, tilting speed, tilting times, tilting angles α1 to α4 at each head position, and grinding time T1 to T4 at each head position.

[0092] When the control system 20 has an actual polishing condition in the database 21a that matches the preset polishing condition for the substrate to be polished, it determines the actual usage amount paired with the actual polishing condition that matches the preset polishing condition as the predicted usage amount of polishing tape used in polishing the substrate. For example, as shown in FIG12, when the preset polishing condition SP matches the actual polishing condition AP1 stored in the database 21a, the control system 20 determines the actual usage amount AU1 paired with the actual polishing condition AP1 as the predicted usage amount of polishing tape used in polishing the substrate.

[0093] The preset polishing conditions for the substrate being polished during the search include at least one of the following: formula name, polishing module identification code, polishing head identification code, polishing belt identification code, polishing mode, belt feed speed, tilting speed, number of tilts, tilt angles α1 to α4 for each head position, and polishing time T1 to T4 for each head position. The polishing conditions used during the search can be only the formula name or a part of the parameters of the polishing conditions. The user can arbitrarily select the polishing conditions used during the search through the input device (not shown in the figure) of the control system 20.

[0094] For example, when searching by formula name, sometimes the database 21a may contain multiple formula names that match the preset polishing conditions of the substrate being polished. The control system 20 can also select the actual polishing condition with the latest formula update date and time from among the multiple actual polishing conditions that match the preset polishing conditions.

[0095] Furthermore, when using formula names for retrieval, even if the formula name of the preset polishing condition for the target substrate matches the formula name of the actual polishing condition, it is possible that the values ​​of previously paired polishing conditions may have changed, resulting in discrepancies between the actual and modified polishing condition values. To determine the correct predicted usage amount, all values ​​in the polishing conditions of the target substrate must match all values ​​in the actual polishing conditions of previously polished substrates. However, using all values ​​in the polishing conditions for retrieval would result in a large amount of data, increasing the processing load on the control system 20. Therefore, the control system 20 generates a hash value for the polishing conditions and uses it as a retrieval hash value, thereby accelerating the processing speed of the control system 20 during retrieval.

[0096] Figure 13 illustrates a method for retrieval using a retrieval hash value. The control system 20 can also generate a retrieval hash value SH corresponding to the preset polishing conditions SP of the substrate to be polished via the computing device 22 (see Figure 1). The retrieval hash value SH is an identification code generated by an algorithm contained in a program stored in the storage device 21 (see Figure 1) based on the parameter values ​​of the preset polishing conditions of the substrate to be polished. This algorithm is the same as the algorithm for generating hash values ​​stored in the database 21a described with reference to Figure 11.

[0097] When the control system 20 finds a hash value in the database 21a that matches the search hash value SH, it determines the actual usage amount paired with the hash value SH as the predicted usage amount of the polishing tape used in polishing the substrate. For example, as shown in FIG13, when the search hash value SH matches the hash value HV1 stored in the database 21a, the control system 20 determines the actual usage amount AU1 paired with the hash value HV1 as the predicted usage amount of the polishing tape used in polishing the substrate.

[0098] In one embodiment, when the preset polishing conditions include polishing steps performed by multiple polishing heads, the control system 20 can also generate a lookup hash value corresponding to the preset polishing conditions for each polishing head. The multiple lookup hash values ​​generated for each polishing head are then paired with the multiple polishing heads. Furthermore, if the control system 20 has a hash value in database 21a that matches the lookup hash value generated for each polishing head, it can also determine the actual amount of polishing tape used in polishing the substrate being polished based on the amount of polishing tape used that matches the hash value generated for each polishing head.

[0099] Next, we will explain the method for determining the predicted amount of polishing tape used in polishing the substrate when there are no actual polishing conditions in the database 21a that match the preset polishing conditions of the substrate to be polished (see step 5 in Figure 10). The control system 20 calculates the predicted amount of polishing tape to be used based on the preset polishing conditions when there are no actual polishing conditions in the database 21a that match the preset polishing conditions of the substrate to be polished.

[0100] The method for calculating the predicted usage of the grinding belt varies depending on the grinding mode. When the grinding mode is continuous grinding, the predicted usage is calculated from the preset grinding conditions of the substrate being ground: belt feed speed, tilting speed, number of tilts, tilt angle α1 at head position G1, and tilt angle α2 at head position G2 (see Figure 6). The tilting time Ta required to tilt from tilt angle α1 at head position G1 to tilt angle α2 at head position G2 is obtained by subtracting the tilt angle α2 at head position G2 from the tilt angle α1 at head position G1, and then dividing by the tilting speed TS (Ta = (α1 - α2) / TS). The tilting time Ta is equivalent to half the time it takes for the grinding head to travel back and forth once between head position G1 and head position G2; therefore, the time required for the grinding head to travel back and forth once is the value obtained by multiplying the tilting time Ta by two. Therefore, the predicted usage amount EUa during continuous grinding is calculated by multiplying the number of tilting times TC by twice the tilting time Ta, and then multiplying by the feed rate FS (EUa = Ta × 2 × TC × FS).

[0101] When the grinding mode is fixed grinding, the predicted usage is calculated from the feed rate of the preset grinding conditions of the substrate being ground, the grinding time T1 at head position G1, the grinding time T2 at head position G2, the grinding time T3 at head position G3, and the grinding time T4 at head position G4 (see Figure 7). The total grinding time is calculated by adding up the grinding times T1 to T4 for each head position G1 to G4. Therefore, the predicted usage EUb for fixed grinding is calculated by multiplying the sum of the grinding times T1 to T4 by the feed rate FS (EUb = (T1 + T2 + T3 + T4) × FS).

[0102] Next, the steps for comparing the remaining amount of polishing tape with the predetermined predicted usage will be explained (see step 6 in Figure 10). When the polishing tape is replaced with a new one, the control system 20 stores the initial length of the new polishing tape in the storage device 21. The initial length can be known in advance from the polishing tape specifications provided by the manufacturer. The remaining amount of polishing tape is calculated as follows: at the end of each polishing operation on the substrate using this polishing tape, the actual amount of polishing tape used in previous polishing operations is subtracted from the initial length. The control system 20 compares the calculated remaining amount of polishing tape with the predetermined predicted usage.

[0103] The comparison between the remaining amount of polishing tape and the predetermined usage amount is performed individually for each of the polishing heads 33A to 33D. More specifically, the control system 20 compares the remaining amount of polishing tapes 32A to 32D supplied to each of the polishing heads 33A to 33D with the corresponding predicted usage amount for each polishing tape 32A to 32D. When the remaining amount of polishing tapes 32A to 32D supplied to the polishing heads 33A to 33D is above the corresponding predicted usage amount, the polishing modules 4A and 4B perform polishing on the substrate under preset polishing conditions. If any of the polishing tapes 32A to 32D has a remaining amount less than the corresponding predicted usage amount, a tape depletion alarm is issued for that polishing head, prompting the user to replace the polishing tape.

[0104] The substrate polishing apparatus shown in Figure 1 can polish multiple substrates simultaneously. Therefore, at the point in time when the control system 20 compares the remaining amount of polishing tape with the predetermined predicted usage, there may be other substrates in the substrate polishing apparatus, either before or during polishing, besides the substrate being polished. In this case, the remaining amount of polishing tape does not reflect the actual usage of polishing tape for the other substrates before or during polishing. The control system 20 can also calculate the remaining amount of polishing tape by subtracting both the actual usage of polishing tape used in previous polishing processes and the predicted usage of polishing tape for the other substrates before or during polishing from the initial length.

[0105] Figure 14 is a top view showing an embodiment of the arrangement of multiple substrates W1 to W5 to be polished. Substrate W1 is placed in the substrate cassette 2 of the loading port 10. Substrate W2 is placed in the standby stage 5A. Substrate W3 is placed in the standby stage 5B. Substrate W4 is polished by the polishing head 33A of the polishing module 4A. Substrate W5 is polished by the polishing head 33C of the polishing module 4B.

[0106] In this embodiment, substrates W1, W2, W3, W4, and W5 are polished by polishing modules 4A and 4B in the same manner. More specifically, substrates W1, W2, W3, W4, and W5 are polished by polishing heads 33A and 33B of polishing module 4A, and then polished by polishing heads 33C and 33D of polishing module 4B. Figure 14 shows substrates W1, W2, and W3 in their pre-polishing state, and substrates W4 and W5 in the polishing process.

[0107] After being polished by polishing head 33C of polishing module 4B, substrate W5 is polished by polishing head 33D. Once polishing of substrate W5 is complete, substrate W5 is transported from polishing module 4B to cleaning and drying unit 7 by second transport robot 17. Afterwards, substrate W5 is cleaned and dried by cleaning and drying unit 7.

[0108] Substrate W4 is polished by polishing head 33A of polishing module 4A, and then polished by polishing head 33B. Once polishing of substrate W4 is complete and substrate W5 is removed from polishing module 4B, substrate W4 is transported from polishing module 4A to polishing module 5A by the second transport robot 17. Afterwards, substrate W4 is polished by polishing head 33C of polishing module 4B, and then by polishing head 33D.

[0109] If substrate W4 is removed from polishing module 4A, substrate W3 is transported from standby stage 5B to polishing module 4A by second transport robot 17. Then, substrate W3 is polished by polishing head 33A of polishing module 4A, and then polished by polishing head 33B.

[0110] If substrate W3 is removed from standby stage 5B, substrate W2 is transported from standby stage 5A to standby stage 5B by the second transport robot 17. If substrate W2 is removed from standby stage 5A, substrate W1 is transferred from the first transport robot 16 to the second transport robot 17, which then places it on standby stage 5A. In this way, multiple substrates W1 to W5 are processed by moving in the order of loading port 10, standby stage 5A, standby stage 5B, polishing module 4A, polishing module 4B, and cleaning and drying unit 7.

[0111] The actions described in steps 2 to 6 with reference to FIG10 are performed before the multiple substrates W1 to W5 to be polished are transported from the substrate cassette 2 of the loading port 10. The control system 20 determines the predicted usage of the polishing belts 32A to 32D used by the polishing heads 33A to 33D. When the remaining amount of polishing belts 32A to 32D is all above the predicted usage, the control system 20 issues a command to the first transport robot 16 to transport the substrate W1 shown in FIG14 from the substrate cassette 2 to the second transport robot 17.

[0112] The control system 20 compares the remaining amount of polishing tapes 32A-32D with the predicted usage at a given time. Since the polishing of substrates W2, W3, W4, and W5 is not yet complete, the actual usage of polishing tapes 32A-32D used in polishing substrates W2-W5 is not yet determined. The control system 20 calculates the remaining amount of polishing tapes 32A-32D by subtracting the predicted usage of polishing tapes 32A-32D for substrates W2-W5 from the current remaining amount. The control system 20 then compares the calculated remaining amount of polishing tapes 32A-32D with the predicted usage.

[0113] According to this embodiment, even when there are other substrates being ground or being ground before the substrate to be ground, the control system 20 can compare the "remaining amount of grinding tape reflecting the predicted usage of grinding tape for other substrates being ground or being ground" with the "predicted usage of grinding tape for the substrate to be ground". This allows for maximum consumption of grinding tape, prevents grinding tape termination errors, and reduces the number of discarded substrates.

[0114] The purpose of describing the above embodiments is to enable those skilled in the art to implement the present invention. Various modifications of the above embodiments can certainly be made by those skilled in the art, and the technical concept of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but should be interpreted as encompassing the maximum scope of the technical concept defined in the claims. [Industry availability]

[0115] This invention can be used in a substrate polishing method that presses an polishing tape onto a substrate such as a wafer to polish the substrate. Furthermore, this invention can be used in a substrate polishing apparatus equipped with a polishing module that presses an polishing tape onto a substrate to polish the substrate. Furthermore, this invention can be used in a process for polishing a substrate using an polishing tape.

[0116] 2: Substrate box 4A, 4B: Grinding Module 5A, 5B: Standby platform 7: Clean the drying section 10: Loading Port 12: First Cleaning Module 13: Second Cleaning Module 14: Drying Module 16: First Delivery Robot 17: Second Delivery Robot 18: The 3rd Delivery Robot 19: The 4th Delivery Robot 20: Control System 21: Storage device 21a: Database 22: Computing device 32A, 32B, 32C, 32D: Grinding belts 32p: Grinding surface 33A, 33B, 33C, 33D: Grinding heads 34: Maintain the stage 35: Axis 37: Maintaining the stage drive mechanism 40: Substrate holding section 42: Lower supply nozzle 43: Upper supply nozzle 46A, 46B: Grinding belt supply mechanism 47: Roll feeder 48: Rewind spool 50, 51, 52, 53: Guide rollers 54: Cylinder 56: Belt feed device 56a: Belt feed roller 56b: Load-bearing roller 60, 61, 62, 63, 64, 65, 66: Guide rollers 68: Pressing component 70A, 70B: Tilting Mechanism 72: Crank arm 73: Arm Rotation Device 100: Casing AP1, AP2, AP3: Actual grinding conditions AU1, AU2, AU3: Actual usage B: Sloping face B1: Upper inclined surface B2: Lower inclined surface B3: Side Cr: Axis E1: Top edge E2: Bottom edge G1, G2, G3, G4: Head position HV1, HV2, HV3: Hash values M: Feed motor NF: Arrow O1: Center R: Arrow SH: Hash value used for retrieval SP: Preset grinding conditions W,W1,W2,W3,W4,W5: substrate

Claims

1. A substrate polishing method, comprising storing in a database the actual polishing conditions of at least one previously polished substrate and the actual amount of polishing tape used in the actual polishing conditions, and pairing the actual polishing conditions with the actual amount of tape used; before polishing the substrate to be polished, retrieving from the database actual polishing conditions that are consistent with the preset polishing conditions of the substrate to be polished; determining the actual amount of polishing tape used that is paired with the actual polishing conditions consistent with the preset polishing conditions as the predicted amount of polishing tape used for polishing the substrate to be polished; comparing the remaining amount of polishing tape used in polishing the substrate to be polished with the previously determined predicted amount of tape used; and polishing the substrate to be polished using a polishing module when the remaining amount of polishing tape is greater than or equal to the predicted amount of tape used.

2. The substrate polishing method of claim 1, wherein, in determining the aforementioned predicted usage amount, when there are no actual polishing conditions in the aforementioned database that are consistent with the aforementioned preset polishing conditions, the predicted usage amount of the aforementioned polishing tape used in polishing the aforementioned substrate is calculated based on the aforementioned preset polishing conditions and thereby determined.

3. The substrate polishing method of claim 1, wherein the aforementioned actual polishing conditions include a polishing head identification code for identifying the polishing head used in polishing at least one previously polished substrate among a plurality of polishing heads, and the aforementioned preset polishing conditions include a polishing head identification code for identifying the polishing head used in polishing the substrate to be polished.

4. The substrate polishing method of claim 1, wherein the aforementioned actual polishing conditions include a polishing belt identification code for identifying the type of polishing belt used in polishing at least one previously polished substrate among a variety of polishing belts, and the aforementioned preset polishing conditions include a polishing belt identification code for identifying the type of polishing belt used in polishing the aforementioned substrate to be polished.

5. The substrate polishing method of claim 1, wherein the aforementioned actual polishing conditions include the polishing conditions of multiple polishing steps included in the polishing of at least one previously polished substrate, the aforementioned actual usage amount is the actual usage amount of polishing tape used from the start to the end of the polishing process including the aforementioned multiple polishing steps, and the aforementioned preset polishing conditions include the polishing conditions of multiple polishing steps applicable to the polishing of the aforementioned substrate.

6. The substrate polishing method of claim 1, wherein a hash value corresponding to the aforementioned actual polishing conditions is generated, and the aforementioned actual usage amount is paired with the aforementioned hash value and stored in the aforementioned database, a retrieval hash value corresponding to the aforementioned preset polishing conditions of the substrate to be polished is generated, and a hash value that matches the aforementioned retrieval hash value is retrieved from the aforementioned database, and in determining the aforementioned predicted usage amount, the actual usage amount of the aforementioned polishing tape that matches the aforementioned retrieval hash value is determined as the predicted usage amount of polishing tape required to polish the aforementioned substrate to be polished.

7. A substrate polishing apparatus, comprising: a polishing module for polishing a substrate to be polished with a polishing tape; and a control system having a database and a computing device; wherein the control system is configured to: store in the database actual polishing conditions of at least one previously polished substrate and the actual amount of polishing tape used in the actual polishing conditions, and pair the actual polishing conditions with the actual amount of polishing tape used; before polishing the substrate to be polished, retrieve from the database actual polishing conditions that are consistent with preset polishing conditions of the substrate to be polished; determine the actual amount of polishing tape used that is paired with the actual polishing conditions that are consistent with the preset polishing conditions as a predicted amount of polishing tape used for polishing the substrate to be polished; compare the remaining amount of polishing tape used in polishing the substrate to be polished with the predicted amount of polishing tape used; and when the remaining amount of polishing tape is greater than or equal to the predicted amount of polishing tape used, issue a command to the polishing module to polish the substrate to be polished.

8. The substrate polishing apparatus of claim 7, wherein the aforementioned control system is configured to: when there are no actual polishing conditions in the aforementioned database that are consistent with the aforementioned preset polishing conditions, calculate the predicted amount of polishing tape to be used in polishing the aforementioned substrate based on the aforementioned preset polishing conditions.

9. The substrate polishing apparatus of claim 7, wherein the aforementioned actual polishing conditions include a polishing head identification code for identifying, among a plurality of polishing heads, the polishing head used in polishing at least one previously polished substrate, and the aforementioned preset polishing conditions include a polishing head identification code for identifying, the polishing head used in polishing the aforementioned target substrate.

10. The substrate polishing apparatus of claim 7, wherein the aforementioned actual polishing conditions include a polishing belt identification code for identifying, among a variety of polishing belts, the type of polishing belt used in polishing at least one previously polished substrate, and the aforementioned preset polishing conditions include a polishing belt identification code for identifying, the type of polishing belt used in polishing the aforementioned substrate to be polished.

11. The substrate polishing apparatus of claim 7, wherein the aforementioned actual polishing conditions include the polishing conditions of multiple polishing steps included in the polishing of at least one previously polished substrate, the aforementioned actual usage amount is the actual usage amount of polishing tape used during the period from the start to the end of polishing including the aforementioned multiple polishing steps, and the aforementioned preset polishing conditions include the polishing conditions of multiple polishing steps applicable to the polishing of the aforementioned substrate to be polished.

12. The substrate polishing apparatus of claim 7, wherein the aforementioned control system is configured to: generate a hash value corresponding to the aforementioned actual polishing conditions; pair the aforementioned actual usage amount with the aforementioned hash value and store it in the aforementioned database; generate a retrieval hash value corresponding to the aforementioned preset polishing conditions of the aforementioned substrate to be polished; retrieve a hash value consistent with the aforementioned retrieval hash value from the aforementioned database; and determine the actual usage amount of the aforementioned polishing tape paired with the hash value consistent with the aforementioned retrieval hash value as the predicted usage amount of polishing tape required for polishing the aforementioned substrate to be polished.

13. A computer-readable recording medium that records a program issues instructions to a control system, causing the computer to perform the following steps: storing in a database the actual polishing conditions of at least one previously polished substrate and the actual amount of polishing tape used in the aforementioned actual polishing conditions, and pairing the aforementioned actual polishing conditions with the aforementioned actual amount of tape used. Before polishing the substrate to be polished, actual polishing conditions that are consistent with the preset polishing conditions of the substrate to be polished are retrieved from the aforementioned database; the actual amount of polishing tape that is matched with the actual polishing conditions that are consistent with the aforementioned preset polishing conditions is determined as the predicted amount of polishing tape required to polish the substrate to be polished. The remaining amount of the aforementioned polishing tape used in polishing the aforementioned substrate to be polished is compared with the previously determined predicted amount; and when the remaining amount of the aforementioned polishing tape is greater than or equal to the previously predicted amount, an instruction is issued to the polishing module to polish the aforementioned substrate to be polished.

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