Method for manufacturing substrate and apparatus for manufacturing substrate

Abstract

This method for manufacturing a substrate includes an adjustment step of adjusting a polishing amount of the substrate according to a correlation between a first variable and a second variable, the first variable being an average power obtained by dividing a total power amount, which is obtained by performing weighting processing on each power amount necessary for driving four motors that move an upper surface plate, a lower surface plate, an internal gear, and a sun gear provided in a double-sided polishing apparatus, by a driving time of the motors, and the second variable being obtained by multiplying the number of substrates by a polishing rate, which is obtained by dividing the polishing amount of the substrate by the driving time of the motors. The correlation is expressed by a relational expression of the polishing amount of the substrate and the power amount which are specified by obtaining coefficients of a regression equation expressing a relationship between the average power and the multiplied value, and the driving time of the motors. The adjustment step includes a driving operation for driving the four motors until the polishing amount of the substrate derived from the relational expression reaches a predetermined target value by sequentially substituting the power amount and the driving time of the motors into the relational expression.

Description

Substrate manufacturing method and substrate manufacturing apparatus

[0001] The present invention relates to a method and apparatus for manufacturing a substrate using a double-side polishing machine.

[0002] When polishing a substrate such as a glass substrate, it has been studied to accurately grasp the state of the polishing apparatus or the object being polished during the polishing process and to control the polishing of the substrate based on the obtained information, thereby performing the polishing process with high precision. Among these, various methods have been studied for polishing glass substrates while precisely controlling the amount of polishing, because this method has a significant effect on the thickness of the glass substrate, which is an important quality characteristic required for glass substrate products.

[0003] For example, infrared-absorbing glass filters are glass filters for adjusting the sensitivity of image sensors called CCD (Charge Coupled Device) sensors or CMOS (Complementary Metal Oxide Semiconductor) sensors used in digital cameras such as cameras in mobile communication terminals, surveillance cameras, and in-vehicle cameras to human visual sensitivity. With the recent trend toward higher precision and smaller size, not only are there increasing demands for the processing accuracy of glass substrates, but there is also a growing demand for mass production. Therefore, there is a need for an efficient manufacturing method that minimizes dimensional variation in the thickness of glass substrates. Conventional methods for controlling the polishing amount of glass substrates include, for example, the following methods (1) to (4).

[0004] (1) For each lot, the polishing rate for the main polishing is calculated using the polishing rate (polishing rate) obtained when polishing is performed in advance, the thickness of the glass substrate before polishing is measured using a mass method or a micrometer method to determine the required polishing amount, and the polishing time is calculated from the polishing rate for the main polishing and the required polishing amount, and the polishing time is determined for each lot. (2) There are methods in which the vertical movement of the upper platen support shaft supporting the upper platen of the polishing device is measured using an eddy current sensor to control the polishing amount of the magnetic disk substrate, and methods in which the relative vertical position of the upper platen support shaft with respect to the slider is identified using a magnescale to control the thickness of the magnetic disk substrate (see, for example, Patent Document 1). (3) There is a method in which a glass substrate for measuring the polishing amount is removed during polishing, and the mass loss of the glass substrate before polishing is measured to control the polishing amount (see, for example, Patent Document 2). (4) There is a method in which, based on a relational expression between the amount of power required to drive a motor provided in a polishing apparatus, the driving time of the motor, and the amount of polishing of the glass substrate, the amount of power and the driving time of the motor are successively substituted into the relational expression while the motor is being driven during actual polishing processing, and the motor is driven until the amount of polishing of the glass substrate derived from the relational expression reaches a predetermined target value.

[0005] Japanese Patent Publication No. 2004-345018 Japanese Patent Publication No. 2008-000825

[0006] However, in the conventional method (1), the polishing rate of the main polishing is calculated using an empirically determined formula for the polishing rate. Therefore, if the polishing rate of the main polishing deviates from the empirical prediction, the polishing amount becomes too large, resulting in the thickness of the substrate, such as a glass substrate, becoming too thin, and the glass substrate must be discarded. Alternatively, the polishing amount is insufficient, and the glass substrate must be polished again to reach the target dimension range. As a result, the dimensional variation of the glass substrate becomes large. Furthermore, the conventional method (2) requires the effort and cost of installing a thickness measurement mechanism in the polishing apparatus. Furthermore, the thickness cannot be controlled with sufficient precision due to vibration of the apparatus, the influence of temperature rise of the apparatus components due to processing, or contamination of the sensor detection point.

[0007] Furthermore, in the above-mentioned conventional method (3), the polishing apparatus is temporarily stopped during polishing, and a glass substrate for measuring the polishing amount is extracted, cleaned, dried, and then its mass is measured, resulting in large variations in the thickness of substrates such as glass substrates and reduced productivity. Furthermore, in the above-mentioned conventional method (4), if the polishing pads attached to the upper and lower plates of the double-sided polishing machine are hard urethane-based pads, the correlation coefficient of the relationship is 0.9 or higher, which is a very good correlation. However, if the polishing pad is a suede-based pad, both the glass substrate and the carrier come into contact with the suede-based pad during double-sided polishing, making it difficult to simply reflect the motor's power consumption in the polishing amount of the glass substrate. This reduces the correlation coefficient of the relationship, resulting in large variations in the thickness of substrates such as glass substrates after polishing between batches. Thus, the current situation is one in which the desired precision cannot be achieved in substrate polishing. The present invention aims to provide a substrate manufacturing method and substrate manufacturing apparatus that can improve the precision of substrate polishing.

[0008] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by the following configuration: (1) A method for manufacturing a substrate, including a polishing step of polishing a substrate using a double-side polishing apparatus equipped with an upper surface plate, a lower surface plate, an internal gear, and a sun gear, comprising an adjusting step of adjusting the amount of polishing of the substrate in accordance with the correlation between a first variable that varies depending on the power or amount of power required to drive four motors for moving the upper surface plate, the lower surface plate, the internal gear, and the sun gear, and a second variable that varies depending on the amount of polishing of the substrate, wherein the first variable is average power, which is a value obtained by dividing the total amount of power obtained by weighting the amount of power required to drive the four motors by the drive time of the four motors, and the second variable is a multiplication value obtained by multiplying the number of substrates by the polishing rate, which is a value obtained by dividing the amount of polishing of the substrate by the drive time of the four motors, and the correlation is expressed by an equation relating the amount of polishing of the substrate, the amount of power, and the drive time of the four motors, which is specified by calculating a coefficient of a regression equation expressing the relationship between the average power and the multiplied value, (2) A method for manufacturing a substrate according to (1), wherein the total amount of power is calculated by equation (A): U'=a×Uupper+b×Uunder+c×Uinter+d×Usun (A) (3) A method for manufacturing a substrate according to (1) or (2), wherein the substrate is a glass substrate.

[0009] (4) A double-side polishing apparatus for polishing a substrate, the apparatus comprising an upper surface plate, a lower surface plate, an internal gear, and a sun gear; and a control unit for adjusting the amount of polishing of the substrate in accordance with a correlation between a first variable that varies depending on the power or amount of power required to drive four motors for moving the upper surface plate, the lower surface plate, the internal gear, and the sun gear, and a second variable that varies depending on the amount of polishing of the substrate, the first variable being an average power obtained by dividing the total amount of power obtained by weighting the amount of power required to drive the four motors by the driving time of the four motors; and a total power consumption of the upper platen, a total power consumption of the lower platen, a total power consumption of the internal gear, and a total power consumption of the sun gear, and coefficients a, b, c, and d are any numbers from 0 to 10. U'=a×Uupper+b×Uunder+c×Uinter+d×Usun (A) (6) The substrate manufacturing apparatus according to (4) or (5), wherein the substrate is a glass substrate.

[0010] According to the present invention, it is possible to provide a substrate manufacturing method and a substrate manufacturing apparatus that can improve the precision of substrate polishing.

[0011] FIG. 1 is a schematic perspective view conceptually showing a double-side polishing apparatus of a substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a first example of a substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a second example of a substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a state in which an upper surface plate is raised in the substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a state in which an upper surface plate is lowered in the substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 6 is a schematic plan view showing an example of a configuration of a lower surface plate, an internal gear, a sun gear, and a carrier in the substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 7 is a schematic cross-sectional view showing an example of a polishing state in the substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 8 is a schematic view showing an example of a drive unit of the substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 9 is a schematic view showing an example of a control system of the substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 10 is a flowchart showing a first example of a substrate manufacturing method according to an embodiment of the present invention.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are merely illustrative for explaining the present invention, and the present invention is not limited to the embodiments shown below. Furthermore, the drawings are simplified for explaining the present invention, and the present invention is not limited to the configuration of the drawings shown below. Note that various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention. In the following, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. For example, when ε is a numerical value ε α ~Number ε β That is, the range of ε is the number ε α and the number ε β The range includes ε α ≦ε≦ε β is.

[0013] The substrate manufacturing method and substrate manufacturing apparatus of the present invention have the following features. When polishing substrates using a double-side polishing apparatus equipped with an upper platen, a lower platen, an internal gear, and a sun gear, the amount of polishing of the substrate is adjusted in accordance with the correlation between a first variable that varies depending on the power or amount of power required to drive four motors for moving the upper platen, the lower platen, the internal gear, and the sun gear, and a second variable that varies depending on the amount of polishing of the substrate. The first variable is average power, which is a value obtained by dividing the total amount of power obtained by weighting the amount of power required to drive the four motors by the drive time of the four motors. The second variable is a multiplication value obtained by multiplying the number of substrates by the polishing rate, which is a value obtained by dividing the amount of polishing of the substrates by the drive time of the four motors. The correlation is expressed by an equation relating the amount of polishing of the substrate, the amount of power, and the drive time of the four motors, which is identified by calculating the coefficient of a regression equation expressing the relationship between the average power and the multiplied value. The electric power amount and the motor drive time are sequentially substituted into a relational expression while the motors are driven, and the four motors are driven to polish the substrate until the substrate polishing amount derived from the relational expression reaches a predetermined target value. This allows the substrate manufacturing method and substrate manufacturing apparatus to estimate the substrate thickness in real time when polishing a substrate using a double-sided polishing apparatus, thereby improving the accuracy of the substrate polishing process. Because the substrate thickness can be estimated in real time, polishing can be automatically stopped when the target thickness is reached. Furthermore, the error between the polished substrate thickness and the target thickness can be reduced. This also reduces the need to re-polish the substrate after polishing. Conventionally, because the substrate thickness cannot be estimated during polishing, it is necessary to collect, clean, dry, and measure the substrate after polishing. This eliminates the need for this series of steps. Furthermore, damage to the substrate that could occur during this series of steps can also be reduced. Furthermore, because the electric power amount and the motor drive time are sequentially substituted into the relational expression while the motors are driven, the motor electric power amount can be recorded as time-series data, enabling data analysis in the double-sided polishing apparatus.

[0014] <Example of Double-Sided Polishing Apparatus> FIG. 1 is a schematic perspective view conceptually illustrating a double-sided polishing apparatus for manufacturing substrates according to an embodiment of the present invention. The double-sided polishing apparatus 11 shown in FIG. 1 is used in the substrate manufacturing apparatus. The double-sided polishing apparatus 11 includes an upper surface plate 12, a lower surface plate 14, an internal gear 15, and a sun gear 16. The upper surface plate 12 and the lower surface plate 14 have circular outer shapes and are arranged facing each other with their outer centers aligned, with the upper surface plate 12 arranged above the lower surface plate 14. An upper polishing pad (not shown) is provided on the surface of the upper surface plate 12 facing the lower surface plate 14 (not shown). The lower surface plate 14 has a recess 14c. A lower polishing pad (not shown) is provided on the bottom surface 14b of the recess 14c of the lower surface plate 14. The lower surface of the substrate 19 is polished by the lower polishing pad (not shown), and the upper surface of the substrate 19 is polished by the upper polishing pad (not shown).

[0015] The internal gear 15 is provided on the inner peripheral surface 14a of the recess 14c of the lower surface plate 14. The sun gear 16 is provided at the center of the bottom surface 14b of the recess 14c of the lower surface plate 14. A gear 17 is provided on the outer peripheral surface 16a of the sun gear 16. Although not shown, the upper surface plate 12, the lower surface plate 14, the internal gear 15, and the sun gear 16 are each connected to a motor, and the double-sided polishing apparatus 11 has a total of four motors. The double-sided polishing apparatus 11 is a four-way type double-sided polishing apparatus that polishes both the upper and lower surfaces of the substrate 19 using the driving force generated by the rotation of the four motors. The motors will be described later. In the double-sided polishing apparatus 11, for example, the upper surface plate 12 rotates in a rotation direction r relative to the central axis C of the sun gear 16. １ The lower surface plate 14, the internal gear 15, and the sun gear 16 rotate in the rotation direction r with respect to the central axis C. ２ Rotation direction r ２ is the rotation direction r １ It is the opposite direction.

[0016] A carrier 18 is provided on the bottom surface 14b of the recess 14c of the lower surface plate 14. The carrier 18 is disk-shaped and holds the substrate 19 to be polished. The carrier 18 is made of, for example, a resin or metal material that is thinner than the substrate 19. The carrier 18 has, for example, a plurality of storage holes 18c arranged concentrically. FIG. 1 illustrates an example of a carrier 18 with three storage holes 18c arranged concentrically, but the arrangement of the storage holes 18c is not particularly limited to a concentric arrangement. The storage holes 18c are formed, for example, with dimensions that allow the outer periphery of the substrate 19 to be stored therein to be held securely without rattle. Note that, while FIG. 1 shows a configuration in which only one carrier 18 is provided, this is not particularly limited, and the number of carriers 18 can be determined according to the size (diameter) of the lower surface plate 14 and the carrier 18.

[0017] A gear 18b is provided on the outer periphery 18a of the carrier 18. The gear 18b of the carrier 18 meshes with the internal gear 15 and the gear 17 of the sun gear 16. The internal gear 15 and the sun gear 16 cause the carrier 18 to rotate about the rotation axis Cs as the center of rotation. The internal gear 15 also causes the carrier 18 to revolve about the central axis C of the sun gear 16. As a result, the carrier 18 rotates about the rotation axis Cs as the center of rotation and revolves about the central axis C of the sun gear 16, and the substrates 19 held by the carrier 18 also rotate and revolve to be polished. This prevents uneven polishing of each substrate 19 and ensures uniform thickness after polishing. In the double-side polishing apparatus 11, the upper surface plate 12 and the lower surface plate 14 rotate relative to each other, i.e., the upper surface plate 12 rotates in the opposite circumferential direction to the lower surface plate 14, allowing the top and bottom surfaces of each substrate 19 held by the carrier 18 between the upper surface plate 12 and the lower surface plate 14 to be simultaneously polished. As will be described later, the substrate manufacturing apparatus includes a double-side polishing machine 11 and a control unit 50 (see FIG. 2) that adjusts the amount of polishing of the substrate. The control unit 50 performs an adjustment step of adjusting the amount of polishing of the substrate, which will be described later.

[0018] <First and Second Examples of Substrate Manufacturing Apparatus> Figure 2 is a schematic cross-sectional view showing a first example of a substrate manufacturing apparatus according to an embodiment of the present invention, and Figure 3 is a schematic cross-sectional view showing a second example of a substrate manufacturing apparatus according to an embodiment of the present invention. In Figures 2 and 3, components identical to those in the double-sided polishing apparatus 11 shown in Figure 1 are designated by the same reference numerals, and detailed descriptions thereof will be omitted. Similar to the double-sided polishing apparatus 11 shown in Figure 1, the substrate manufacturing apparatus 10a shown in Figure 2 and the substrate manufacturing apparatus 10b shown in Figure 3 each include a double-sided polishing apparatus 11 including an upper surface plate 12, a lower surface plate 14, an internal gear 15, and a sun gear 16, and further includes a control unit 50 for adjusting the amount of polishing of the substrate 19. The substrate manufacturing apparatus 10a shown in Figure 2 and the substrate manufacturing apparatus 10b shown in Figure 3 will be described below. The substrate manufacturing apparatus 10a will hereinafter be simply referred to as the manufacturing apparatus 10a, and the substrate manufacturing apparatus 10b will hereinafter be simply referred to as the manufacturing apparatus 10b.

[0019] 2 is configured to simultaneously polish the top and bottom surfaces of a plurality of substrates 19, and includes a base 20, a lower surface plate 14, an upper surface plate 12, an elevating mechanism 22, and a rotation transmission mechanism 24. The lower surface plate 14 is rotatably supported on the upper part of the base 20. Inside the base 20, motors M1 to M4 (see FIG. 8) are provided as driving units that rotate the upper surface plate 12, the lower surface plate 14, the internal gear 15, the sun gear 16, etc.

[0020] The lower surface plate 14 has a bottom surface 14b (see FIG. 1) provided with a lower polishing pad (not shown) for polishing the lower surface of the substrate 19 held by the carrier 18. The upper surface plate 12 is disposed above and opposite the lower surface plate 14 and has an upper polishing pad (not shown) for polishing the upper surface of the substrate 19.

[0021] The lifting mechanism 22 is supported by, for example, a gate-shaped frame 26 that stands above the base 20, and has a lifting cylinder device 28 that lifts and lowers the upper surface plate 12 during carrier replacement. The lifting cylinder device 28 is attached to the center of a beam 27 of the frame 26 so as to be able to extend and retract in a downward direction. A piston rod 29 of the lifting cylinder device 28 extends downward, and a shaft member 31 that fits into the inner periphery of a bearing 30 is connected to the tip of the piston rod 29. The bearing 30 rotatably supports the upper surface plate 12. A rotary joint is provided at the bottom of the shaft member 31.

[0022] Furthermore, suspending member 32 fitted to the outer periphery of bearing 30 is attached so as to suspend upper surface plate 12. Therefore, when piston rod 29 of lifting cylinder device 28 is driven upward or downward, upper surface plate 12 connected to piston rod 29 via suspending member 32 is also driven at the same time to rise or fall.

[0023] Furthermore, the beams 27 of the frame 26 are provided with dressing positioning stopper mechanisms 33 on both sides of the lifting cylinder device 28. These dressing positioning stopper mechanisms 33 position the upper surface plate 12 raised by the thickness of the dress carrier (e.g., approximately 20 mm) when performing the dressing process to smooth the surface of the polishing pad, as described below. The dressing positioning stopper mechanism 33 includes a horizontally mounted horizontal driving cylinder device 34 and a stopper plate 35 supported on the tip of the piston rod of the horizontal driving cylinder device 34. The stopper plate 35 is normally retracted to the outside of the lifting cylinder device 28 and is driven toward the center during the dressing process to position the piston rod 29 at a position elevated by the thickness of the dress carrier. Note that the dressing positioning stopper mechanism 33 is not necessary, and other configurations may be used to position the upper surface plate 12 during the dressing process.

[0024] In the substrate manufacturing apparatus 10b shown in Figure 3, a universal joint 36 connected to the center of a suspension member 32 is coupled to the lower tip of the piston rod 29. The suspension member 32 includes a plurality of support columns 32a extending in the vertical direction and an annular mounting member 32b fixed to the lower ends of the support columns 32a. The upper surface of the upper surface plate 12 is fixed to the lower surface of the annular mounting member 32b. Therefore, when the piston rod 29 of the lifting cylinder device 28 is driven upward or downward, the upper surface plate 12, which is connected via the piston rod 29, universal joint 36, and suspension member 32, is also driven simultaneously to rise or fall.

[0025] In the substrate manufacturing apparatus 10a shown in Fig. 2 and the substrate manufacturing apparatus 10b shown in Fig. 3, the control unit 50 controls the upper surface plate 12, the lifting mechanism 22, and the rotation transmission mechanism 24. In addition, the double-sided polishing apparatus 11 of the substrate manufacturing apparatus 10a shown in Fig. 2 and the substrate manufacturing apparatus 10b shown in Fig. 3 is a four-way double-sided polishing apparatus that polishes the substrate 19 (see Fig. 1) by driving forces generated by the rotation of four motors.

[0026] FIG. 4 is a schematic cross-sectional view showing a state in which the upper surface plate is raised in a substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a state in which the upper surface plate is lowered in a substrate manufacturing apparatus according to an embodiment of the present invention. FIG. 6 is a schematic plan view showing an example of the configuration of the lower surface plate, internal gear, sun gear, and carrier in a substrate manufacturing apparatus according to an embodiment of the present invention. In FIGS. 4 to 6, components that are the same as those in the double-sided polishing apparatus 11 shown in FIG. 1 and the substrate manufacturing apparatuses 10a and 10b shown in FIGS. 2 and 3 are designated by the same reference numerals, and detailed descriptions thereof will be omitted. FIG. 4 is a schematic cross-sectional view showing a state in which the upper surface plate is raised. FIG. 4 shows a state in which the upper surface plate 12 of the substrate manufacturing apparatus 10b shown in FIG. 3 is raised as a representative example.

[0027] When replacing a carrier or pad, the upper surface plate 12 is raised by the lifting cylinder device 28 and moves above (in the Za direction) the lower surface plate 14. In this raised state, multiple substrates and carriers 18 that have been placed on the upper surface of the lower surface plate 14 and have undergone the polishing process can be removed, and another or the same cleaned carrier 18 and unpolished substrates can be mounted on the upper surface of the lower surface plate 14.

[0028] 2, the rotation transmission mechanism 24 has a cylindrical coupling portion 39 formed on the upper end of a motor drive shaft 38 of a motor M1 for moving the upper surface plate 12. The coupling portion 39 has, on its upper surface, a plurality of coupling pins 42 that fit into coupling holes 41 provided in driven holes 40 of the upper surface plate 12. The tips of the coupling pins 42 are formed in a conical shape that makes them easy to insert into the coupling holes 41. When the upper surface plate 12 is lowered by the lifting cylinder device 28, the upper surface plate 12 is lowered while aligning alignment marks provided in advance on the upper surface plate 12 and the coupling portion 39, thereby aligning the relative positions of the coupling holes 41 and the coupling pins 42.

[0029] 3, the rotation transmission mechanism 24 has a key (claw) 44 that can fit into a key groove (recess) 43 formed on the upper side surface of a coupling portion 39 that passes through a center hole (not shown) of the upper surface plate 12. The key 44, which protrudes toward the inner periphery of the upper surface plate 12, is attached to the annular mounting member 32b by a support shaft 45 so as to be swingable around the support shaft 45 as the swing center.

[0030] When the upper surface plate 12 is lowered, the key 44 fits into the key groove 43, and when the upper surface plate 12 is raised, the key 44 is separated from the key groove 43. When the key 44 and the key groove 43 are fitted together, the drive torque of the motor M1 connected to the rotation shaft of the upper surface plate 12 is transmitted to the upper surface plate 12 via, for example, a drive gear, and the upper surface plate 12 rotates together with the coupling portion 39.

[0031] Figure 5 schematically shows the state in which the upper surface plate 12 has been lowered. Figure 5 also shows the state in which the upper surface plate 12 is in contact with the upper surfaces of multiple substrates placed on the lower surface plate 14 under its own weight or a predetermined pressure. As shown in Figure 5, the supply pressure P1 of compressed air to the lower chamber of the lifting cylinder device 28 is lowered. At this time, the upper chamber of the lifting cylinder device 28 is open to the atmosphere, and P2 is atmospheric pressure. As a result, when the piston rod 29 of the lifting cylinder device 28 is driven downward (in the Zb direction) by the weight of the upper surface plate 12, the upper surface plate 12 is lowered together with the hanging member 32.

[0032] In the case of the substrate manufacturing apparatus 10a shown in FIG. 2, the rotational torque of the motor M1 for moving the upper surface plate 12 is transmitted to the upper surface plate 12 via the connecting pins 42 and connecting holes 41 that stand up in the coupling portion 39. Furthermore, since the rotation transmission mechanism 24 is configured so that the connecting pins 42 and connecting holes 41 fit together, it is configured so that, compared to the substrate manufacturing apparatus 10b having a key structure shown in FIG. 3, a component force in the vertical direction is not generated by preventing vertical movement (a kneading movement) that accompanies the engagement of the key 44 with the key groove 43 formed extending in the axial direction of the coupling portion 39. When manufacturing a substrate, the substrate manufacturing apparatus 10a having the connecting pin structure shown in FIG. 2 or the substrate manufacturing apparatus 10b having the key structure shown in FIG. 3 may be used.

[0033] Furthermore, motors M1 to M4 that rotate and drive the upper surface plate 12, lower surface plate 14, internal gear 15, sun gear 16, etc. are disposed inside the base 20 and are not provided on the frame 26. This configuration lowers the center of gravity of the entire apparatus, suppressing vibrations during polishing operation and further improving stability during polishing operation.

[0034] As shown in FIG. 6 , a sun gear 16 is inserted from below into a rotation center hole (not shown) in the bottom surface 14b of the recess 14c of the lower surface plate 14. A gear 17 is provided on the outer circumferential surface 16a of the sun gear 16. An internal gear 15 is provided on the inner circumferential surface 14a of the recess 14c of the lower surface plate 14. For example, four carriers 18 are provided on the bottom surface 14b of the lower surface plate 14. Furthermore, for example, four storage holes 18c for storing substrates 19 are provided concentrically in the carriers 18. A gear 18b is provided on the outer circumferential surface 18a of the carriers 18. The gear 18b of the carriers 18 meshes with the sun gear 16 and the internal gear 15. Therefore, the carriers 18 are rotated by a motor M3 provided on the base 20 of the lower surface plate 14, and the internal gear 15 rotates circumferentially relative to the sun gear 16. That is, the internal gear 15 rotates in the opposite circumferential direction to the sun gear 16, and at the same time, revolves around the sun gear 16 while rotating on its own axis. The sun gear 16 and the internal gear 15 are also rotated on their own axes by the motors M2 and M4 that drive them, respectively. This prevents uneven polishing of the substrates 19 stored in the storage holes 18c of each carrier 18, making it possible to make the thickness of the substrates uniform after polishing.

[0035] FIG. 7 is a schematic cross-sectional view showing an example of a polishing state of a substrate manufacturing apparatus according to an embodiment of the present invention. As shown in FIG. 7 , during polishing, a lower polishing pad 46 held on the bottom surface 14b of the lower surface plate 14 contacts the underside of each substrate 19, and an upper polishing pad 47 held on the upper surface plate 12, which has been lowered to the polishing position by the lifting mechanism 22, contacts the upper surface of each substrate 19. Therefore, in the double-sided polishing apparatus 11, by rotating the upper surface plate 12 in the opposite circumferential direction relative to the lower surface plate 14 as described above, the upper and lower surfaces of each substrate 19 held on the carrier 18 between the upper surface plate 12 and the lower surface plate 14 can be simultaneously polished. The surfaces of the lower polishing pad 46 and the upper polishing pad 47 that contact each substrate 19 constitute the polishing surfaces. The lower polishing pad 46 and the upper polishing pad 47 are made of, for example, hard urethane, suede, or nonwoven fabric. The same material is used for the lower polishing pad 46 and the upper polishing pad 47.

[0036] Next, the configuration of the drive unit provided on the base 20 will be described. Figure 8 is a schematic diagram showing an example of the drive unit of the substrate manufacturing apparatus according to an embodiment of the present invention. The upper surface plate 12, the lower surface plate 14, the sun gear 16, and the internal gear 15 are supported rotatably around the same axis on a platform 21 provided on the lower surface 20a inside the base 20. A motor M1 is connected to the motor drive shaft 38, which is the rotation axis of the upper surface plate 12. A motor M3 is connected to the lower surface plate 14. A motor M2 is connected to the sun gear 16. A motor M4 is connected to the internal gear 15. The upper surface plate 12 rotates at a rotation speed corresponding to the driving force of the motor M1, for example, in a rotation direction r １ The lower surface plate 14 rotates in the direction r (see FIG. 1) at a rotation speed corresponding to the driving force of the motor M2. ２ The lower surface plate 14 rotates in the opposite direction to the upper surface plate 12 (see FIG. 2). The sun gear 16 rotates at a rotation speed corresponding to the driving force of the motor M3, for example, in the rotation direction r ２ The internal gear 15 rotates at a rotation speed corresponding to the driving force of the motor M4, for example, in a rotation direction r ２ The motors M1 to M4 are connected to each other via drive gears to transmit rotational power. The four motors M1 to M4 are drive motors.

[0037] FIG. 9 is a schematic diagram showing an example of a control system of a substrate manufacturing apparatus according to an embodiment of the present invention. As shown in FIG. 9 , the control unit 50 is electrically connected to the lifting cylinder device 28, the pressure mechanism 48, the motors M1 to M4 provided inside the base 20, a notification unit 52 such as a monitor or speaker, an input unit 54 that accepts input information from an operator or another control unit, and a sensor 56 for calculating the power or amount of power of the motors M1 to M4. The control unit 50 generates control signals for controlling each device. A monitor 57 is also connected to the control unit 50. The control unit 50 may be configured as a computer equipped with a central processing unit (CPU), a dedicated device configured with dedicated circuits, or a server configured to run on the cloud. For example, the control signals are generated by executing a program (computer software) stored in a read-only memory (ROM) or the like in the processing unit.

[0038] The input unit 54 is an interface device that receives information from outside the control unit 50 and transmits the information to the control unit 50. The input unit 54 has, for example, an operation unit through which an operator inputs input information, or a communication interface device that enables connection to an external computer. The operation unit is, for example, a touch panel, a button, a lever, a keyboard, etc.

[0039] The sensor 56 is a detection sensor that detects the power or amount of power of the motors M1 to M4. Examples of the sensor 56 include a rotation speed detection sensor that detects the rotation speed of the motors M1 to M4, and a current detection sensor that detects the current flowing through the motors M1 to M4. In this case, the control unit 50 calculates the power or amount of power of the motors M1 to M4 in accordance with an output signal corresponding to the detection value of the sensor 56. The amount of power is the integrated value of the power over time. Therefore, if the sensor 56 can detect the power of the motors M1 to M4, the control unit 50 can calculate the amount of power of the motors M1 to M4 by calculating the integrated value of the power over time of each of the motors M1 to M4.

[0040] In addition, the control unit 50 controls the pressurizing / depressurizing operation of the pressure mechanism 48, which increases or decreases the pressure applied by the upper surface plate 12 to the upper surfaces of the substrates placed on the lower surface plate 14, and the rotation of the motors M1 to M4, which rotate the upper surface plate 12, etc., in accordance with the output signal from the sensor 56. The amount of substrate polishing is adjusted based on the polishing time. The monitor 57 displays, for example, input information input via the input unit 54, the power or power consumption of the four motors, information representing a data set of the first variable (described below), i.e., the value of "U' / t" in equation (4) and the value of RN in equation (4), a scatter diagram plotting the data set, and a calibration curve. The monitor 57 also displays the substrate polishing conditions, the thickness of the substrate before polishing, the set value of the thickness of the substrate after polishing, and the estimated thickness of the substrate. The monitor 57 is not particularly limited, and various known displays, such as a liquid crystal display, can be used.

[0041] <Method for Adjusting the Amount of Substrate Polishing> As described above, various methods for adjusting (controlling) the amount of substrate polishing have been considered. For example, one conventional method counts the elapsed time from the start of polishing by rotating motors M1 to M4, and stops motors M1 to M4 to terminate substrate polishing when a preset time has been reached. However, in this conventional method, the "predetermined time" is empirically set based on the amount of polishing required until the substrate thickness reaches a specified value. For example, it is set by comprehensively taking into account various conditions, such as the substrate hardness, the abrasive particle size of the pad, the type of slurry, the pad pressure, the platen rotation speed, and the polishing rate of the previous lot. Therefore, because this predetermined time is set empirically, there may be a large discrepancy between the amount of polishing predicted before polishing and the amount of polishing actually achieved after polishing. Since the thickness of the substrate cannot be measured during polishing, the actual amount of polishing can be determined by measuring the thickness of the substrate after polishing.

[0042] In contrast, in the present invention, the adjustment of the substrate polishing amount is automatically controlled using the relationship between the integrated value (total power amount) of the load power of the four motors mounted on the substrate polishing apparatus and the polishing amount. It can be thought of as "the total power amount of the motor is equal to the sum of the power amount of the motor when no load is applied and the power amount required by the motor for polishing." By setting each item as follows, the total motor power amount U (kJ) can be expressed by the following formula (1). The following formula (1) shows that the polishing amount is proportional to the total motor power amount. U (kJ) = U Ｖ NV+P ０ t (1) U (kJ): Integrated value of load power (total power) N (pieces): Number of substrates in one batch (one lot) (number of substrates placed on all carriers of the double-side polishing machine and polished) U Ｖ (kJ / μm): Load power required to polish one substrate by 1 μm V (μm): Polishing amount (change in thickness) P ０ (μW): Power of steady load (idle rotation) t (seconds): Polishing time

[0043] The above formula (1) can be transformed to obtain the following formula (2). The following formula (2) includes time as a variable. Therefore, if the calibration curve obtained using the above formula (1) as is is used, the accuracy of the calibration curve may decrease. In other words, the accuracy of predicting the polishing amount may decrease, and as a result, the accuracy of the substrate polishing process may not be improved. Here, when the average power is used, the following formula (3) is obtained. The following formula (3) does not include time as a variable. Therefore, it is possible to suppress the decrease in the accuracy of the calibration curve. Note that R in the following formula (3) is expressed as R = V / t and represents the polishing rate (μm / sec).

[0044]

[0045]

[0046] As is clear from equation (3), when "U / t" is considered as one variable and "RN" is considered as one variable, "RN" can be expressed as a linear function of "U / t". The total amount of power U required to drive the four motors is further weighted to obtain a total amount of power U' (kJ) for each of the amounts of power required to drive the four motors. As a result, equation (3) above becomes equation (4) below. The total amount of power U' obtained by weighting each of the amounts of power required to drive the four motors described above is the weighted integrated amount of power (kJ).

[0047]

[0048] "U' / t" in equation (4) corresponds to a first variable that changes depending on the power or amount of power required to drive the four motors. "RN" in equation (4) corresponds to a second variable that changes depending on the amount of polishing V of the substrate. Note that "U / t" in equation (3) is the total amount of power U required to drive the four motors divided by the polishing time t, that is, the average power value required to drive the four motors during the polishing time t (the drive time of the four motors). Here, when polishing a substrate, all four motors start and stop at the same time. Therefore, the drive time of the four motors is the drive time of any one of the four motors. Therefore, the drive time of the motors can be obtained by measuring the drive time of any one of the four motors. Furthermore, since the substrate is polished by driving the four motors, the drive time of the motors is the polishing time. The drive time of the motors is the elapsed time from when the motors start to rotate to when they stop rotating. The rotation of the motor is controlled by the control unit 50, and the time elapsed from when the motor starts to rotate to when the motor stops to rotate is counted by the control unit 50.

[0049] "U' / t" in equation (4), i.e., the first variable, is the average power, which is the total amount of power U' required to drive the four motors, weighted for each amount of power, divided by the driving time of the four motors. The weighting process for each amount of power required to drive the four motors will be described later. The second variable "RN" is the product of the number of substrates N multiplied by the polishing rate. The polishing rate is the value obtained by dividing the amount of substrate polished by the driving time (polishing time t) of the four motors.

[0050] When a substrate is polished using four motors (for the upper surface plate, the lower surface plate, the sun gear, and the internal gear), the second variable "RN" and the sum of the variables "U / t" for each of the four motors are plotted. When actual data is plotted, a linear correlation exists between the variable "U / t" and the second variable "RN," as shown in equation (3). From this, it can be estimated that, in equation (4) above, a linear correlation exists between the first variable "U' / t" and the second variable "RN," as in equation (3). The correlation is a relationship between the substrate polishing amount, the amount of power consumed, and the drive time of the four motors, identified by calculating the coefficients of a regression equation expressing the relationship between the average power and the multiplied value. This relationship represents a calibration curve showing the relationship between the first variable "U' / t" and the second variable "RN." From this relationship, i.e., the calibration curve, the substrate polishing amount can be estimated with high accuracy. The above-mentioned amounts of power and the drive times of the four motors are successively substituted into the relational equation while the four motors are being driven, and the four motors are driven until the amount of substrate polishing derived from the relational equation reaches a predetermined target value. Here, the power or amount of power required to drive the motors and the drive times of the four motors are recorded during polishing. Successive substitution means inputting the above-mentioned amounts of power and drive times of the four motors obtained at predetermined time intervals into the relational equation. The power or amount of power required to drive the above-mentioned motors can also be, for example, the average power or average amount of power over a predetermined period.

[0051] The above-mentioned relational expression is obtained by performing a regression analysis on the relationship between the actual data representing the first variable "U' / t" and the actual data representing the second variable "RN" to obtain the unknown first coefficient (1 / U Ｖ ) and the unknown second coefficient (-P ０ / U Ｖ ) can be calculated. For example, the least squares method is used for the regression analysis. In the least squares method, the closer the correlation coefficient is to 1, the higher the correlation between the first variable "U' / t" and the second variable "RN".

[0052] The first coefficient (1 / U Ｖ ) and the second coefficient (-P ０ / U Ｖ ) into equation (4) to obtain the above-mentioned relational expression. The relational expression shows the relationship between "RN," which is the product of the polishing rate and the number of substrates, and the average power "U' / t." The relational expression shows a calibration curve. At the time of obtaining the relational expression, the above-mentioned coefficients a, b, c, and d (weighting coefficients) and the number of substrates are determined and are constants. The average power is the time average of the total power amount obtained by weighting the power amounts of the four motors. Therefore, the control unit 50 counts the elapsed time from the start of motor rotation, obtains the motor drive time, and calculates the total power amount U' at predetermined time intervals. According to equation (4) with the determined coefficients, i.e., the relational expression, the total power amount U' obtained by weighting the power amounts of the four motors and the motor drive time are sequentially substituted into the relational expression to calculate the estimated polishing amount from the relational expression. The calculated estimated polishing amount is compared with the target value of the polishing amount (target polishing amount), and the four motors are driven until the calculated estimated polishing amount reaches the predetermined target value of the polishing amount (target polishing amount). When the estimated amount of polishing reaches a predetermined target value (target amount of polishing), the rotation of the four motors is stopped, thereby enabling the actual amount of polishing of the substrate to be adjusted very accurately to the target value (target amount of polishing). The estimated amount of polishing will be described later.

[0053] In this manner, in a polishing process in which substrates are polished by driving four motors provided in a substrate manufacturing apparatus, substrate processing can be controlled with high precision by performing a control operation to control substrate polishing based on the total amount of power obtained by weighting the amounts of power required to drive the four motors and the motor drive times. The control operation to control substrate polishing is performed by the control unit 50. To control substrate processing with high precision, a control operation to control substrate polishing is performed sequentially while the motors are driven based on the total amount of power obtained by weighting the amounts of power required to drive the four motors and the motor drive times. More specifically, while the motors are driven, the total amount of power consumed by the four motors per second is used to control substrate polishing based on data on the average power consumed by the four motors per second. This improves the precision of substrate polishing.

[0054] <First Example of Substrate Manufacturing Method> FIG. 10 is a flowchart showing a first example of a substrate manufacturing method according to an embodiment of the present invention. The substrate manufacturing method uses, for example, the substrate manufacturing apparatuses 10a and 10b described above. Each of the substrate manufacturing apparatuses 10a and 10b is configured with four motors M1 to M4 for driving the upper surface plate 12, the lower surface plate 14, the internal gear 15, and the sun gear 16. Furthermore, when manufacturing substrates, the type and number of substrates are determined, and polishing conditions for the substrates are set. In the substrate manufacturing method, substrates 19 are attached to the carrier 18 of the double-side polishing apparatus 11, and the substrates are polished based on the polishing conditions. During this process, the integrated power consumption for each of the four motors is measured, and the polishing time is recorded. Furthermore, after polishing is completed, the thickness of the substrate is measured to obtain data on the amount of polishing of the substrate (step S10). As described above, the polishing time is the motor drive time. Step S10 is a process for acquiring data for obtaining the above-described time format. Therefore, the above data is acquired for each predetermined polishing time or for each of multiple polishing conditions, thereby obtaining multiple data.

[0055] Next, for each data acquired in step S10, a weighting process is performed on the integrated power consumption of each of the four motors to obtain a total power consumption. The weighted total power consumption is the total power consumption U' in equation (4). The total power consumption U' is divided by the polishing time (motor driving time) to obtain the first variable, i.e., the value of "U' / t" in equation (4). The polishing rate is also obtained from the substrate polishing amount and the polishing time (motor driving time). The second variable, i.e., the value of RN in equation (4), is obtained by multiplying the number of substrates by the polishing rate. The second variable is also referred to as the multiplication value. In this way, a data set of the first variable and the second variable is obtained for one data item acquired in step S10. That is, a data set of the value of "U' / t" in equation (4) and the value of RN in equation (4) is obtained. For all the data acquired in step S10, a data set of the first variable, i.e., the value of "U' / t" in equation (4), and the second variable, i.e., the value of RN in equation (4), is acquired and plotted on a scatter diagram (step S12). The data set plotted on the scatter diagram can be displayed on a monitor.

[0056] Next, in step S12, a regression analysis is performed on the data set of the actual data of the first variable and the actual data of the second variable for all the data acquired in step S10, to find the coefficient of the regression equation that expresses the relationship between the average power and the multiplication value. That is, the first coefficient (1 / U Ｖ ) and the second coefficient (-P ０ / U Ｖ ) is calculated. This allows the relationship between the amount of polishing of the substrate, the amount of power consumed, and the driving times of the four motors to be obtained (step S14). As described above, the regression analysis may be performed using, for example, the least squares method. Although the data set is plotted on a scatter diagram in step S12, step S12 is not necessarily required if the relationship can be obtained in step S14.

[0057] The substrate manufacturing method uses the relational expression obtained in step S14. Next, the pre-polishing thickness of the substrate to be polished is measured. If multiple substrates are being polished, the thickness of the thickest substrate is taken as the pre-polishing thickness of the substrate. The pre-polishing thickness of the substrate is input to the substrate manufacturing apparatus (controller 50) via the input unit 54 (step S16). The post-polishing thickness of the substrate is also set. The set post-polishing thickness of the substrate is input to the substrate manufacturing apparatus via the input unit 54 (step S16). The controller 50 calculates the target substrate removal amount from the pre-polishing thickness and post-polishing thickness of the substrate, and sets the target removal amount. The relational expression obtained in step S14 is input to the substrate manufacturing apparatus (controller 50) via the input unit 54 (step S16). In step S16, preset substrate polishing conditions are also input to the substrate manufacturing apparatus (controller 50) via the input unit 54. As described above, in the substrate manufacturing method, the controller 50 performs an adjustment step to adjust the substrate removal amount.

[0058] Next, the substrate 19 is mounted on the carrier 18 of the substrate manufacturing equipment, and double-sided polishing of the substrate 19 is performed (step S18). In step S18, based on the substrate polishing conditions, the four motors M1 to M4 rotate the upper surface plate 12, the lower surface plate 14, the internal gear 15, and the sun gear 16 to polish both sides of the substrate 19. After the substrate polishing begins (step S18), the sensor 56 measures the integrated power consumption of the four motors, and the power consumption required to drive each of the four motors is weighted to obtain the total power consumption. The motor drive time, i.e., the polishing time, is also recorded, and the average power consumption is calculated from the total power consumption and the polishing time. The average power consumption is calculated by applying the above-mentioned relational equation (calibration curve) to obtain the value of RN. The polishing amount is estimated based on the obtained value of RN (step S20). In step S20, if the value of RN is α and the estimated polishing amount is Ve, then α = (Ve / t)N, and the estimated polishing amount Ve = αt / N. The number of substrates N is known, the polishing time t is measured, and the value α of RN is obtained from the relational expression, so that the estimated polishing amount Ve can be obtained. The estimated polishing amount Ve is determined by sequentially substituting the above-mentioned amounts of power and the driving times of the four motors into the relational expression while the four motors are driving.

[0059] Next, the estimated amount of polishing Ve obtained in step S20 is compared with the target amount of polishing (step S22). If the estimated amount of polishing Ve reaches the target amount of polishing in step S22, the drive of the four motors is stopped to stop polishing (step S24). This completes polishing of the substrate and the substrate is manufactured. On the other hand, if the estimated amount of polishing Ve does not reach the target amount of polishing in step S22, polishing continues and the estimated amount of polishing is calculated again (step S20). The estimated amount of polishing is repeatedly calculated until the estimated amount of polishing Ve reaches the target amount of polishing (step S20). The series of steps S20, S22, and S24 described above corresponds to the adjustment process for adjusting the amount of polishing of the substrate. As described above, in the adjustment process, after polishing of the substrate starts (step S18), in step S20, while the four motors are driven, the estimated amount of polishing Ve is calculated by sequentially substituting the above-mentioned amounts of power and the drive times of the four motors into a relational equation. In step S22, if the estimated polishing amount Ve has not reached the target polishing amount, polishing is continued, and a driving operation is performed to drive the four motors until the estimated polishing amount Ve reaches the target polishing amount (predetermined target value).

[0060] In step S22, for example, a tolerance value of the estimated amount of polishing Ve is set relative to the target amount of polishing. In this case, in step S22, if the estimated amount of polishing Ve is within the tolerance value relative to the target amount of polishing, it is determined that the estimated amount of polishing Ve has reached the target amount of polishing. The setting of the tolerance value is not particularly limited, and may be set so as not to exceed the target amount of polishing, or may be set so as to exceed the target amount of polishing, for example.

[0061] <Second Example of Method for Manufacturing Substrate> A second example of a method for manufacturing a substrate will now be described with reference to the flowcharts shown in Figures 11 and 12. Figures 11 and 12 are flowcharts showing the second example of a method for manufacturing a substrate according to an embodiment of the present invention.

[0062] In step S30 of FIG. 11 , the control unit 50 checks whether the power switch of the double-sided polishing machine has been turned on. If the power switch is turned on, the process proceeds to step S31. In step S31, the supply pressure P1 to the lower chamber of the lifting cylinder device 28 is increased. At this time, the upper chamber of the lifting cylinder device 28 is open to the atmosphere, and P2 is set to atmospheric pressure. This drives the piston rod 29 upward, lifting the upper surface plate 12 together with the suspending member 32 (see FIG. 4 ). This driving of the piston rod 29 separates the upper surface plate 12 above the lower surface plate 14. In the next step S32, an operator places the carrier 18 on the upper surface of the lower surface plate 14. Subsequently, in step S33, an operator attaches substrates 19 (see FIG. 6 ) to the storage holes 18c (see FIG. 6 ) of the carrier 18 (see FIG. 6 ).

[0063] In step S34, the control unit 50 reduces the supply pressure P1 to the lower chamber of the lifting cylinder device 28. At this time, the upper chamber of the lifting cylinder device 28 is open to the atmosphere, and P2 is atmospheric pressure. This causes the piston rod 29 to be driven downward (in the Zb direction) by the weight of the upper surface plate 12 (see FIG. 5). This driving of the piston rod 29 causes the upper surface plate 12 and the suspending member 32 to descend to the stroke end of the piston rod 29. When the connecting hole 41 of the upper surface plate 12 engages with the connecting pin 42 of the coupling portion 39 (see FIG. 2) or when the key 44 connected to the upper surface plate 12 engages with the key groove 43 of the coupling portion 39 (see FIG. 3), the upper polishing pad 47 arranged on the underside of the upper surface plate 12 abuts against the upper surface of each substrate 19 held by the carrier 18. When the upper polishing pad 47 is in contact with the substrates 19, a pressure acts on the upper surface of each substrate 19 due to the mass of the upper surface plate 12 or a predetermined pressure.

[0064] In step S35, the control unit 50 sets the input values ​​input from the input unit 54 as the polishing conditions for this time. For example, the number of substrates N, the thickness of the substrate before polishing, and the thickness of the substrate after polishing are input as input values. The control unit 50 calculates a target polishing amount for the substrate from the thickness of the substrate before polishing and the thickness of the substrate after polishing, and sets the target polishing amount. Furthermore, the relational expression is determined in advance as described above and set in the control unit 50.

[0065] In step S36, the control unit 50 supplies the slurry from the upper surface plate 12 (for example, through a plurality of holes drilled in the upper surface plate 12). Then, the process proceeds to step S37, where the motors M1 to M4 are activated to transmit the driving forces of the motors to the lower surface plate 14 and the upper surface plate 12. In step S38, immediately after the start of polishing, the control unit 50 causes the pressure mechanism 48 to perform a pressure operation. As a result, the upper polishing pad 47 attached to the lower surface of the upper surface plate 12 is brought into close contact with the upper surface of each substrate 19 held by the carrier 18 at a predetermined pressure by the pressure operation of the pressure mechanism 48.

[0066] 2, in step S38, immediately after the start of polishing, the control unit 50 supplies compressed air to the air bag of the pressure mechanism 48. When compressed air is supplied to the air bag, the air bag expands downward, and the pressure of the air bag causes the upper polishing pad 47 attached to the lower surface of the upper platen 12 to come into close contact with the upper surface of each substrate 19 held by the carrier 18.

[0067] In the next step S39, the polishing time (platen rotation drive time), which is the drive time of the motors, is counted, and the sensor 56 acquires the integrated value of the power (integrated power amount) from the time the motors are driven. In step S40, similar to step S20 described above, the control unit 50 performs a weighting process on the amount of power required to drive each of the four motors to obtain a total power amount, and then obtains the average power from the total power amount and the polishing time. After applying the average power to the above-mentioned relational expression (calibration curve), the control unit 50 acquires the estimated polishing amount Ve as described above. The control unit 50 compares the estimated polishing amount Ve with the target polishing amount (predetermined target value) and determines whether the estimated polishing amount Ve has reached the target polishing amount. If the estimated polishing amount Ve has not reached the target polishing amount, polishing is continued without stopping the drive of the four motors, and the estimated polishing amount is again calculated (step S40).

[0068] If it is determined in step S40 that the target removal amount has been reached, the process proceeds to step S41 in FIG. 12, where the control unit 50 controls the pressure mechanism 48 to depressurize the pressure to stop polishing the substrate. The release of pressure through the depressurization operation stops polishing of the substrate. For example, in the case of the double-sided polishing apparatus 11 shown in FIG. 2, if the target removal amount has been reached in step S40, the process proceeds to step S41 in FIG. 12. In step S41, to stop polishing of the substrate, the compressed air inside the air bag of the pressure mechanism 48 is exhausted to reduce the pressure to the atmosphere, thereby releasing the pressure applied by the air bag. The release of pressure through the air bag stops polishing of the substrate. The series of steps S39 to S41 described above corresponds to an adjustment process for adjusting the substrate removal amount. Step S40 includes a drive operation for driving the four motors until the estimated removal amount Ve reaches the target removal amount (predetermined target value).

[0069] At the point in time when it is determined in step S40 that the estimated amount of polishing Ve sequentially derived using the relational expression has reached the target amount of polishing, polishing of the substrate may be stopped by releasing the pressure applied by the pressure mechanism 48. Alternatively, polishing of the substrate may be stopped by gradually reducing the applied pressure of the pressure mechanism 48, or by stopping the rotation of the motor.

[0070] In the next step S42, the motors M1 to M4 are de-energized to reduce the rotational torque to zero. Then, in step S43, the supply of slurry is stopped. In the next step S44, the notification unit 52 notifies the user by voice guidance or monitor display that polishing has been completed.

[0071] Next, proceeding to step S45, the supply pressure P1 to the lower chamber of the lifting cylinder device 28 is increased. At this time, the upper chamber of the lifting cylinder device 28 is open to the atmosphere, and P2 is set to atmospheric pressure. This causes the piston rod 29 to move upward, moving the upper surface plate 12 above the lower surface plate 14 (in the Za direction) (see FIG. 4). This upward movement of the upper surface plate 12 makes it possible to remove the multiple substrates 19 and carrier 18 for which polishing has been completed. In the next step S46, an operator removes the carrier 18 from the lower surface plate 14. Next, in step S47, an operator removes all of the substrates 19 for which polishing has been completed from the lower surface plate 14.

[0072] In the next step S48, the worker determines whether the lower polishing pad 46 and the upper polishing pad 47 are clogged and confirms whether pad replacement is necessary. Whether the lower polishing pad 46 and the upper polishing pad 47 need to be replaced due to clogging can be determined, for example, by the cumulative polishing time, the number of polishing processes, or by an operator's measurement of the pad groove depth. It can also be determined by the motor power or power consumption. Furthermore, if the worker determines in step S48 that the lower polishing pad 46 and the upper polishing pad 47 are clogged, the worker selects whether pad replacement or dressing is necessary. If the worker determines that pad replacement is necessary, the process proceeds to step S51.

[0073] Furthermore, if pad replacement is not required, the operator checks in step S49 whether or not dressing is required for the lower polishing pad 46 and the upper polishing pad 47. If dressing is not required, the operator checks in step S50 whether or not polishing should be continued. If polishing is to be continued in step S50, the operator returns to step S31 described above and repeats the procedures from step S31 onwards.

[0074] Next, in step S51, the worker removes the upper polishing pad 47 from the upper surface plate 12. Then, a new upper polishing pad 47 is attached to the underside of the upper surface plate 12. The lower polishing pad 46 attached to the lower surface plate 14 can also be replaced. In the case of a double-sided polisher, it is preferable to replace both the upper and lower polishing pads at the same time in order to stabilize the polishing accuracy, etc.

[0075] After this, the process proceeds to step S52, where the operator performs pad dressing on the lower polishing pad 46 and the upper polishing pad 47. That is, after raising the upper surface plate 12 using the lifting cylinder device 28, the dressing carrier is placed above the lower surface plate 14, and the upper surface plate 12 is lowered to the dressing height position. With the upper surface plate 12 lowered to the dressing height position, the dressing process is performed while applying a predetermined pressure. At this time, the piston rod 29 of the lifting cylinder device 28 is restricted in its lowered position by the stopper plate 35 of the dressing positioning stopper mechanism 33 (see FIG. 2 ), and the upper surface plate 12 may be positioned at a position raised by the thickness of the dressing carrier. A diamond dresser is attached to the dressing carrier, and the pad surfaces of the lower polishing pad 46 and the upper polishing pad 47 are smoothed by the diamond dresser.

[0076] When the pad dressing process is completed, the upper surface plate 12 is raised by the lifting cylinder device 28, and the dressing carrier is removed. After this, the process returns to the process of step S31 described above, and the processes from step S31 onward are repeated. Also, if it is determined in step S49 that the lower polishing pad 46 and the upper polishing pad 47 need to be dressed, the process also proceeds to step S52 described above, and the worker performs the pad dressing process on the lower polishing pad 46 and the upper polishing pad 47. After this, the process returns to the process of step S31 described above, and the processes from step S31 onward are repeated.

[0077] For example, the amount of power or electric energy required to drive the motor may be used to determine when to perform a dressing process on the polishing pad or when to replace the polishing pad. The amount of power or electric energy required to drive the motor may also be used to determine when to replace the polishing slurry. The amount of power or electric energy required to drive the motor may also be used to determine when to adjust the upper and lower surface plates. For example, the control unit 50 uses the amount of power or electric energy required to drive the motor to determine when to perform a dressing process, when to replace the polishing pad, and when to replace the polishing slurry. This allows for predetermined tasks such as dressing and replacement of the polishing pad, thereby reducing variations in the substrate polishing rate. This improves the characteristics of the polished substrate, such as scratches, surface waviness, surface roughness, and edge shape (sagging), thereby maintaining consistent quality. The control unit 50 may also use the amount of power or electric energy required to drive the motor to detect cracks in the substrate during polishing, and may stop polishing the substrate if a crack is detected. This allows for stable production of substrates.

[0078] (Weighting Process) When obtaining the above-mentioned relational expression, the total amount of power (weighted integrated power) obtained by weighting each amount of power required to drive the four motors is used. By using the total amount of power obtained by weighting each amount of power required to drive the four motors, the correlation coefficient indicating the correlation between the first variable "U' / t" and the second variable "RN" can be increased. For example, when U' is the total amount of power, Uupper is the total amount of power for the upper surface plate, Uunder is the total amount of power for the lower surface plate, Uinter is the total amount of power for the internal gear, and Usun is the total amount of power for the sun gear, and the coefficients a, b, c, and d are any numbers between 0 and 10, the total amount of power is calculated using equation (A). a, b, c, and d are called weighting coefficients. U' = a × Uupper + b × Uunder + c × Uinter + d × Usun (A) For example, in an unweighted state, when the coefficients a, b, c, and d are set to 1.0, the correlation coefficient is 0.79. It has been confirmed that, for example, when the coefficient a is set to 2.0, the coefficient b is set to 0.5, the coefficient c is set to 1.0, and the coefficient d is set to 0.2, the correlation coefficient becomes 0.84.

[0079] The weighting coefficients for the upper surface plate, lower surface plate, internal gear, and sun gear are determined, for example, as follows. The contributions of the upper surface plate, lower surface plate, internal gear, and sun gear to substrate polishing are calculated in advance, and weighting coefficients are determined according to the contributions. Of the upper surface plate, lower surface plate, internal gear, and sun gear, the upper surface plate and lower surface plate have the greatest contribution to substrate polishing. The lower surface plate is affected by factors other than substrate polishing more than the upper surface plate due to the added mass of the upper surface plate. Therefore, of the upper and lower surface plates, the upper surface plate is less affected by other factors with respect to substrate polishing, and the motor power or amount of power required to rotate the upper surface plate reflects the amount of substrate polishing more than the lower surface plate. Furthermore, the internal gear and sun gear only rotate the carrier, and therefore contribute less to substrate polishing than the upper and lower surface plates. In this way, the contribution of each of the upper and lower plates, the internal gear, and the sun gear to substrate polishing is determined, and weighting coefficients are set based on the determined contributions. From the above, it is preferable that the weighting coefficient of the upper platen is larger than that of the lower platen. Furthermore, it is preferable that the sum of the weighting coefficients of the internal gear and the sun gear is smaller than the sum of the weighting coefficients of the upper and lower plates.

[0080] The total power amount using the weighting coefficients (weighted integrated power amount) is not limited to being calculated using the above formula (A). The total power amount using the weighting coefficients can also be calculated using formulas (B) to (D), for example. In the following formula (D), the coefficients a, b, c, and d do not include 0. U' = (Uupper + a) + (Uunder + b) + (Uinter + c) + (Usun + d) (B) U' = (Uupper - a) + (Uunder - b) + (Uinter - c) + (Usun - d) (C) U' = (Uupper / a) + (Uunder / b) + (Uinter / c) + (Usun / d) (D)

[0081] As described above, the lower polishing pad 46 and the upper polishing pad 47 are, for example, hard urethane pads or suede pads. Suede pads are softer than hard urethane pads and may come into contact with carriers as well as substrates during polishing. Therefore, the motor power reflects the amount of substrate polishing to a lesser extent than hard urethane pads, so it is preferable to use the total power amount obtained by weighting the amount of power required to drive the motors. In this weighting process, it is preferable to set weighting coefficients for the four motors according to their contribution to substrate polishing. Setting such weighting coefficients is effective for increasing the correlation coefficient of the relational expression, which, in turn, leads to reduced variation in substrate thickness between batches when polishing with soft suede pads, making this preferable.

[0082] Here, for the double-sided polishing machine 11 configured as shown in FIG. 1 , the total amount of power required to drive the four motors was weighted to determine the correlation coefficient between the first variable "U' / t" and the second variable "RN" in the above formula (4). The correlation coefficient was determined by setting the weighting coefficients a, b, c, and d as shown in Examples 2 to 6 below. Example 1 below is an example in which the coefficients a, b, c, and d have the same value and are not weighted. Therefore, Example 1 corresponds to an example in which the correlation coefficient between the first variable "U / t" and the second variable "RN" in the above formula (3) was determined. In addition, suede-based pads were used for both the upper and lower polishing pads in the double-sided polishing machine 11.

[0083]

[0084] As shown in Table 1 above, by performing weighting processing as shown in Examples 2 to 6, the correlation coefficient can be made larger than in Example 1, where weighting processing is not performed. Specifically, in the weighting processing, the weighting coefficient of the upper surface plate is made larger than that of the lower surface plate, and the weighting coefficient of the lower surface plate is made larger than 0.0, thereby making the correlation coefficient larger than in Example 1, where weighting processing is not performed. As shown in Examples 2 to 6, the coefficients a, b, c, and d for the upper surface plate, lower surface plate, internal gear, and sun gear can make the correlation coefficient larger than in Example 1, where weighting processing is not performed. Therefore, when the coefficient b of the lower surface plate is 0.0 or more and 6.0 or less, the coefficient a of the upper surface plate is preferably 1.0 or more and 8.0 or less, the coefficient c of the internal gear is preferably 0.0 or more and 9.0 or less, and the coefficient d of the sun gear is preferably 0.0 or more and 3.0 or less.

[0085] <Example of Substrate> The substrate to be polished is not particularly limited, and may be, for example, a glass substrate. Examples of glass substrates include glass substrates for magnetic recording media, glass substrates for photomasks, glass substrates for displays such as liquid crystal or organic electroluminescence (EL), and glass substrates for optical components such as lenses, optical filters, and optical pickup elements. In addition to the above, examples of glass substrates include amorphous glass substrates, crystallized glass substrates, and chemically strengthened glass substrates. The raw glass substrate of the glass substrate may be manufactured by the float method or by a press molding method. The substrate may also be a semiconductor substrate such as a silicon substrate or a silicon carbide substrate, a ceramic substrate, or a resin substrate. Examples of ceramic substrates include substrates for semiconductor devices, substrates for high-frequency circuits, substrates for power conversion devices, and LED (light-emitting diode) substrates. Examples of resin substrates include printed circuit boards, flexible substrates, multilayer substrates, and hybrid substrates.

[0086] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0087] This application is based on a Japanese patent application (Patent Application No. 2024-113832) filed on July 17, 2024, the contents of which are incorporated herein by reference.

[0088] According to the present invention, the precision of polishing a substrate can be improved. The present invention is useful for a substrate manufacturing method and a substrate manufacturing apparatus that use a double-side polishing apparatus including an upper surface plate, a lower surface plate, an internal gear, and a sun gear.

[0089] DESCRIPTION OF SYMBOLS 10a, 10b Substrate manufacturing apparatus 11 Double-sided polishing apparatus 12 Upper surface plate 14 Lower surface plate 14a Inner peripheral surface 14b Bottom surface 15 Internal gear 16 Sun gear 16a Outer peripheral surface 17 Gear 18 Carrier 18a Outer periphery 18b Gear 18c Storage hole 19 Substrate 20 Base 20a Bottom surface 21 Table 22 Elevating mechanism 24 Rotation transmission mechanism 26 Frame 27 Beam 28 Elevating cylinder device 29 Piston rod 30 Bearing 31 Shaft member 32 Hanging member 32a Support 32b Annular mounting member 33 Dressing positioning stopper mechanism 34 Horizontal driving cylinder device 35 Stopper plate 36 Universal joint 38 Motor drive shaft 39 Joint portion 40 Driven hole 41 Connecting hole 42 Connecting pin 43 Key groove 44 Key 45 Support shaft 46 Lower polishing pad 47 Upper polishing pad 48 Pressurizing mechanism 50 Control unit 52 Notification unit 54 Input unit 56 Sensor 57 Monitor C Central axis Cs Rotation axis M1, M2, M3, M4 Motor r １ , r ２ Rotation direction

Claims

1. A method for manufacturing a substrate, comprising a polishing step of polishing a substrate using a double-side polishing machine equipped with an upper surface plate, a lower surface plate, an internal gear, and a sun gear, the method comprising: an adjustment step of adjusting the amount of polishing of the substrate in accordance with the correlation between a first variable that varies depending on the power or amount of power required to drive four motors for moving the upper surface plate, the lower surface plate, the internal gear, and the sun gear, and a second variable that varies depending on the amount of polishing of the substrate; the first variable is average power, which is a value obtained by dividing the total amount of power obtained by weighting the amount of power required to drive the four motors by the driving time of the four motors; and the second variable is a multiplication value obtained by multiplying the number of substrates by the polishing rate, which is a value obtained by dividing the amount of polishing of the substrate by the driving time of the four motors; and the correlation is expressed by an equation relating the amount of polishing of the substrate, the amount of power, and the driving time of the four motors, which is specified by calculating a coefficient of a regression equation expressing the relationship between the average power and the multiplied value. a substrate manufacturing method, wherein the adjustment step includes a drive operation of sequentially substituting the amount of power and the drive times of the four motors into the relational equation while the four motors are being driven, and driving the four motors until the amount of polishing of the substrate derived from the relational equation reaches a predetermined target value.

2. The method for manufacturing a substrate according to claim 1, wherein the total power amount is calculated by formula (A) where U' is the total power amount, Uupper is the total power amount of the upper surface plate, Uunder is the total power amount of the lower surface plate, Uinter is the total power amount of the internal gear, and Usun is the total power amount of the sun gear, and coefficients a, b, c, and d are any numbers between 0 and 10. U'=a×Uupper+b×Uunder+c×Uinter+d×Usun (A) 3. The method for manufacturing a substrate according to claim 1 or 2, wherein the substrate is a glass substrate.

4. A double-side polishing apparatus for polishing substrates, comprising an upper surface plate, a lower surface plate, an internal gear, and a sun gear; and a control unit for adjusting the amount of polishing of the substrate in accordance with the correlation between a first variable that changes according to the power or amount of power required to drive four motors for moving the upper surface plate, the lower surface plate, the internal gear, and the sun gear, and a second variable that changes according to the amount of polishing of the substrate, wherein the first variable is average power, which is a value obtained by dividing the total amount of power obtained by weighting the amount of power required to drive the four motors by the driving time of the four motors; and the second variable is a multiplication value obtained by multiplying the number of substrates by the polishing rate, which is a value obtained by dividing the amount of polishing of the substrates by the driving time of the four motors; and the correlation is expressed by an equation relating the amount of polishing of the substrate, the amount of power, and the driving time of the four motors, which is specified by calculating a coefficient of a regression equation expressing the relationship between the average power and the multiplied value. the control unit sequentially substitutes the amount of power and the drive times of the four motors into the relational equation while the four motors are being driven, and drives the four motors to polish the substrate until the amount of polishing of the substrate derived from the relational equation reaches a predetermined target value.

5. The substrate manufacturing apparatus according to claim 4, wherein U' is the total power amount, Uupper is the total power amount of the upper surface plate, Uunder is the total power amount of the lower surface plate, Uinter is the total power amount of the internal gear, and Usun is the total power amount of the sun gear, and the coefficients a, b, c, and d are any numbers between 0 and 10, and the total power amount is calculated by formula (A): U'=a×Uupper+b×Uunder+c×Uinter+d×Usun (A) 6. The substrate manufacturing apparatus according to claim 4 or 5, wherein the substrate is a glass substrate.

Images