TWI744539B - Substrate for semiconductor and manufacturing method thereof - Google Patents

Abstract

[Problem] To provide a semiconductor substrate that does not deform or has little deformation even when film formation or high-temperature heat treatment is performed, and a method for manufacturing the same.　　[Solution] A semiconductor substrate having one surface with convex SORI and the other surface with concave SORI of the same degree as the SORI, and a thickness deviation of 3 μm or less.

Description

Substrate for semiconductor and manufacturing method thereof

The present invention relates to a substrate for a semiconductor and a manufacturing method thereof.

In semiconductor integrated circuits (LSI: Large Scale Integration) or TFT-LCD (Thin Film Transistor-Liquid Crystal Display), the requirements for miniaturization and high-speed operation are increasing, and the films formed on semiconductor substrates are becoming denser.

If the flatness of the polysilicon TFT substrate is impaired, it may be due to the fact that the glass wafer is pinched during the manufacturing process of the liquid crystal display device, or the robot is transported, resulting in improper suction or inability to hold, or the formation of In the photolithography process of applying fine patterns in the process of polysilicon TFT, improper pattern overlap and deterioration are caused.　　 Furthermore, in a liquid crystal panel, if the flatness of the two transparent glass bodies does not match each other, the film thickness of the liquid crystal sandwiched between them is also difficult to become uniform, resulting in uneven color and poor quality.　　 Also, in the case of using polysilicon thin film to manufacture TFT-LCD, as the processing temperature reaches 1000°C or higher, the substrate causes viscous deformation and warp deformation.

In order to solve these problems, for example, Patent Document 1 proposes to provide an active device substrate made of a high-purity quartz glass material with excellent heat resistance by suppressing the hydroxyl concentration and chlorine concentration.　　 Furthermore, Patent Document 2 proposes a method of forming a silicon nitride film on the front and back of the substrate to offset the stress on the front and back of the substrate to prevent warpage of the substrate. In addition, Patent Document 3 discloses that by setting the fluorine concentration within a certain range, and using quartz glass that does not substantially contain alkali metal oxides, the density change caused by the virtual temperature is reduced, and the high temperature treatment before and after The method of using quartz glass substrate for polysilicon TFT LCD with excellent dimensional stability. [Prior Technical Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. 6-11705 　　 [Patent Document 2] Japanese Patent Application Publication No. 11-121760 　　 [Patent Document 3] Japanese Patent Application Publication No. 2005-215319

[The problem to be solved by the invention]

However, in the method of Patent Document 1, even if the flatness of the quartz glass material is improved, the deformation caused by the film stress of the subsequent polysilicon thin film cannot be suppressed. Furthermore, in the method of Patent Document 2, the warpage cannot be excluded unless the same film is formed on the front and back of the substrate. However, the same film is used to form both sides of the TFT side and the color filter side. In general, it is difficult to suppress deformation even with this method. "Also, even with the method of Patent Document 3, although the dimensional stability before and after the high temperature treatment is excellent, it is not one that can suppress the deformation caused by the film stress.

The present invention was created in view of the above-mentioned circumstances, and its object is to provide a semiconductor substrate and a manufacturing method thereof that does not deform or is less deformed even in the case of film formation or high-temperature heat treatment. [Means to solve the problem]

In order to achieve the above-mentioned object, the inventors of the present invention have studied carefully and found that the use of a double-sided polishing device, a single-sided polishing device, a double-sided polishing device, or a single-sided polishing device commonly used in the manufacture of semiconductor substrates can be used at low cost. It also produces semiconductor substrates with good reproducibility that can be controlled arbitrarily and with less thickness deviation. More specifically, the above-mentioned apparatus assumes that the semiconductor substrate is deformed by film stress or high-temperature heat treatment. , Considering the amount of deformation in advance, and planning to produce a substrate with a shape that warps in the opposite direction to the deformation, so that no deformation or less deformation can be obtained even in the case of film formation or high-temperature heat treatment Of the semiconductor substrate, and completed the present invention.

That is, the present invention provides the following: 　　 1. A semiconductor substrate characterized by having one surface of SORI having a convex shape, and the other surface of SORI having a concave shape of the same degree as the above-mentioned SORI, And the thickness deviation is 3 μm or less.　　2. The semiconductor substrate as in 1, wherein the SORI of each of the above-mentioned surfaces is 50~600μm.　　3. The semiconductor substrate of 1 or 2, wherein the BOW of one of the above-mentioned convex SORI faces is +25~+300.　　4. The semiconductor substrate according to any one of 1 to 3, wherein the BOW of the other side of the SORI having the above-mentioned concave shape is -25 to -300.　　 5. The semiconductor substrate as in any one of 1 to 4, wherein the thickness is 0.5 to 3 mm.　　6. The semiconductor substrate according to any one of 1 to 5, wherein the shape of the semiconductor substrate is a circular shape with a diameter of 100 to 450 mm or a rectangular shape with a diagonal length of 100 to 450 mm in a plan view.　　7. The semiconductor substrate according to any one of 1 to 6, wherein it is made of synthetic quartz glass.　　 8. The substrate for semiconductors as in any one of 1 to 7, which is a substrate for polysilicon TFT. 9. A method of manufacturing a semiconductor substrate, comprising: a 　　 preparation process, which prepares a transfer master disk, and the transfer master disk has a surface and a back surface, and has a The middle point on the center line of the center point, the plane orthogonal to the above center line, the SORI and the thickness deviation of the above surface and back side symmetrically; The double-sided polishing device is equipped with two raw material substrates, and processes the surface of each raw material substrate that does not contact the transfer master to make the shape of the transfer master that is transferred to the two sides of each single side. Sheet transfer substrate; 　　 polishing process, which is by polishing both sides of the transfer substrate, or by polishing only the surface of the transfer substrate that does not transfer the shape of the transfer master in the transfer process To make a polished substrate; and grind both sides or one side of the polished substrate. 10. A method of manufacturing a semiconductor substrate, comprising: a 　　 preparation process, which prepares a transfer master, and the transfer master has a surface and a back surface, as opposed to the center connecting the front and back surfaces The middle point on the center line of the point is the plane orthogonal to the center line, any one of the front and back surfaces is parallel, and the other surface of the front and back surfaces that is in contact with the raw substrate is orthogonal to the above The center line is at the same time symmetrical with respect to the center line; the transfer process involves setting the raw substrate in the single-sided polishing device in contact with the other surface of the transfer master, and the raw substrate is The surface that is not in contact with the transfer master is processed to produce a transfer substrate in which the shape of the transfer master is transferred to a single side; the 　　 polishing process is performed by polishing the double of the transfer substrate Surface, or by polishing only the surface of the transfer substrate that has not been transferred with the shape of the transfer master in the transfer process to prepare a polished substrate; and for the double-sided or single-sided polished substrate To grind. [Effects of Invention]

According to the present invention, it is possible to provide a semiconductor substrate having a specific SORI and thickness deviation in consideration of film stress or deformation of the semiconductor substrate due to high-temperature heat treatment in advance. Therefore, even when film formation or high-temperature heat treatment is performed later, a semiconductor substrate of a desired shape can be obtained. Furthermore, the semiconductor substrate of the present invention can be manufactured with a double-sided polishing device, a single-sided polishing device, or a double-sided polishing device or a single-sided polishing device commonly used in the manufacture of semiconductor substrates at low cost and with good reproducibility. .

Hereinafter, the present invention will be specifically described. "The semiconductor substrate related to the present invention is characterized by having one surface with convex SORI and the other surface with SORI concave to the same degree as SORI, and a thickness deviation of 3 μm or less. In this way, by deliberately manufacturing semiconductor substrates that warp in the opposite direction to the deformation after film formation or high temperature heat treatment before film formation or high temperature heat treatment, the stage of manufacturing the device or the stage of assembly can be used. Obtained a semiconductor substrate of the desired shape. Specifically, a semiconductor substrate that is warped in advance to have a concave shape that is the same degree as when it is changed into convexity by film formation or a high-temperature heating process, and a convex shape that is the same degree as that when it is changed into a concave shape is manufactured.

Although the SORI in the semiconductor substrate of the present invention is not particularly limited, as long as the final obtained semiconductor substrate can be made into the desired shape, from the viewpoint of operability, it is preferably 50 to 600 μm, and more preferably It is 100~400μm, the best is 100~200μm. The aspect of SORI in the present invention is not particularly limited. For example, when a semiconductor substrate is deformed into a convex shape center-symmetrically by a film formation or high-temperature heating process, if a center-symmetric concave semiconductor substrate is manufactured That is (refer to Figure 1(A)), if the semiconductor substrate is deformed into a convex shape and the center of the vertex is shifted to the convex shape in the Y-axis direction, it is sufficient to manufacture a concave semiconductor substrate that matches the deviation (refer to 1(B)), the semiconductor substrate is deformed into a convex shape that is line symmetric with respect to the line passing through the center. If a line symmetric concave semiconductor substrate is manufactured (see FIG. 1(C)).

Here, SORI in the present invention refers to the sum of the minimum (absolute value) a and the minimum (absolute value) b of the distance between the least square plane S and the surface of the semiconductor substrate A ( SORI=|a|+|b|).　　 In addition, if the surface of the substrate sufficiently reflects light, and the interference pattern with the reference surface of the device can be obtained, the SORI can be measured with an optical interference flat tester. Conversely, if the substrate surface is rough and no interference pattern can be obtained, the SORI can be obtained by scanning the laser displacement meter by nipping the surface and back of the substrate.

In addition, in the semiconductor substrate of the present invention, the thickness deviation (TTV) is considered to facilitate focusing during exposure, and the pattern thickness is set to be 3 μm or less, preferably 2 μm or less, and more preferably 1 μm or less.　　 Here, the thickness deviation, as shown in Fig. 4, means that the thickness of the thinnest part is subtracted from the thickness of the thickest part on the surface of the substrate A. In addition, the thickness deviation is the same as SORI and can be measured using an optical interference flatness tester or a laser displacement meter.

Furthermore, the semiconductor substrate of the present invention preferably has a BOW of +25~+300 on one side of the SORI having the above-mentioned convex shape, and preferably has a BOW of -25~+300 on the other side of the SORI having the above-mentioned concave shape. -300 is better. In the present invention, BOW digitizes the difference between the center of the substrate surface and the height of the least square average surface obtained as a surface reference, and defines it as a + sign on the upper side of the reference surface and a sign on the lower side. -symbol. In this way, at least in the center of the substrate, it can be determined whether the shape of the substrate is convex or concave. When SORI is convex, the BOW on one side is preferably +25~+300, more preferably +25~+200, most preferably +25~+100, and the BOW on the other side is preferably- 25~-300, more preferably -25~-200, most preferably -25~-100. In addition, when SORI is concave, the BOW on one side is preferably -25~-300, more preferably -50~-200, most preferably -50~-100, and the BOW on the other side is better It is +25~+300, more preferably +50~+200, most preferably +50~+100.　　In this way, in addition to the above-mentioned specific SORI, by specifying the height of the center of the substrate like BOW, the convex and concave can be more clearly defined as the numerical value, and a semiconductor substrate of the desired shape can be obtained.

Here, the BOW in the present invention is as shown in FIG. 3, with the intersection point of the reference plane S2 obtained from the front and back middle surface e and the substrate center line f orthogonal to the reference surface S2, and the front and back middle surface e In the distance d, if the front and back middle surface e is higher than the reference surface S2, it is marked as positive, and if the front and back middle surface e is lower than the reference surface S2, it is marked as negative. The absolute value d is defined as BOW.　　 In addition, if the surface of the substrate reflects light sufficiently, and the interference pattern with the reference surface of the device can be obtained, the BOW can be measured with an optical interference flat tester. Conversely, when the substrate surface is rough and no interference pattern can be obtained, the BOW can be obtained by scanning the laser displacement meter by nipping the surface and back of the substrate.

Furthermore, although the thickness of the semiconductor substrate is not particularly limited, it is preferably 0.5 to 3.0 mm, and more preferably 0.6 to 1.2 mm from the viewpoint of the operability of the substrate or the thickness that can be introduced by the exposure device.

In the present invention, the shape of the semiconductor substrate is not particularly limited, and a general shape such as a circular shape or a rectangular shape in plan view can be adopted. Furthermore, although the diameter or diagonal length of these is not particularly limited, it is preferably 100 to 450 mm, and more preferably 200 to 300 mm. Although the material of the semiconductor substrate of the present invention is not particularly limited, it can be made of glass materials, ceramic materials and other known materials, but from the point of view that the substrate for transmissive polysilicon TFT requires light to pass through, it can be synthesized Quartz glass substrate is preferred. In the case of reflective TFTs, polysilicon substrates are preferred.

As a method of manufacturing the semiconductor substrate of the present invention having the above-mentioned SORI and BOW, a method of forming the desired shape in any of the cutting process, polishing process, and polishing process can be considered. However, in the dicing process, when a general wire saw performs cutting, the ingot is cut while applying the slurry containing the abrasive material to the linearly stretched wire, so the obtained semiconductor substrate is horizontal. The direction is the direction of the wire, and it becomes linear with the wire. In addition, although the vertical direction perpendicular to the wire direction on the surface of the semiconductor substrate is used to lower or raise the ingot, this direction is caused by a mechanism that moves linearly with good reproducibility, making it difficult Curvilinear movement and arbitrary control of SORI and BOW.　　Furthermore, since the thickness of the semiconductor substrate is relatively thin relative to the diameter, the substrate, which becomes the driving force for the production of the expected SORI shape in the polishing process or the polishing process, has less repeated stress. Therefore, it is difficult to set the SORI on the surface to be convex, that is, to set the BOW positive, and to set the SORI on the back to concave, that is to set the BOW, because the SORI and BOW are maintained as they are even if they are polished. Negative, etc., freely control the shape of the substrate.

Therefore, in the present invention, a transfer master is used to manufacture semiconductor substrates having expected SORI and BOW shapes in a polishing process. The shape of the transfer master used in the present invention differs depending on the type of polishing device used in the transfer process or the shape of the target semiconductor substrate. For example, in the case of using a double-sided polishing device, a centrally symmetrical SORI-shaped semiconductor substrate can be prepared by: a preparation process, which prepares a transfer master, and the transfer master has a surface and a back surface. Relative to the midpoint on the center line connecting the center points of the front and back surfaces, the surface orthogonal to the center line, the surface and the back surface symmetrically face SORI and thickness deviation; In the method of mastering, two raw material substrates are installed in the double-sided polishing device, and the surface of each raw material substrate that is not in contact with the transfer master is processed to make the shape of the transfer master. The shape of the transfer master is transferred to each single side The two-piece transfer substrate; polishing process, which is to polish both sides of the transfer substrate obtained in the transfer process, or only polish the surface of the transfer master plate in the transfer substrate that has not been transferred. Polished and processed substrates, and manufactured by grinding both sides or one side of the polished substrates.

Furthermore, in the case of using a single-sided polishing device, a symmetrical SORI-shaped semiconductor substrate can be prepared by: a preparation process, which is to prepare a transfer master, which has a surface and a back surface, and is opposite to By connecting the middle point on the center line of the center points of the front and back sides, the surface orthogonal to the center line, any one of the front and back sides is parallel, and the other side of the front and back sides that is in contact with the raw substrate The surface is orthogonal to the center line, and at the same time symmetrical with respect to the center line; the transfer process is to connect with the other side of the prepared transfer master, and set the raw substrate in the single-sided polishing device to face the raw substrate. Among them, the surface that is not in contact with the transfer master is processed to produce a transfer substrate in which the shape of the transfer master is transferred to a single side; the polishing process is to polish both sides of the transfer substrate, or only polish The shape of the transfer master in the transfer substrate has no surface to be transferred to make a polished substrate, and the polished substrate is polished on both sides or one side.

The double-sided polishing device and the single-sided polishing device used in the present invention are not particularly limited, and can be appropriately selected and used from well-known devices. Transferring the double-side polishing apparatus projects and the number of rotations of the single-side polishing apparatus preferably 5 ~ 50rpm begin with, the load at 10 ~ 200g / cm preferably, in the double-side polishing apparatus, per unit of time to the substituted ^2-bis It is better if the faces are almost the same.

Although the material of the transfer master is not particularly limited, alumina ceramics, metals, resins, etc. can be used, but from the viewpoint of deformation or damage, alumina ceramics are preferred.　　Furthermore, as the abrasive, in addition to using an alumina-based abrasive with an average particle size of preferably 5-20μm, and using 20-60% by mass dispersed in water, silicon carbide or artificial diamonds can also be used.

In the transfer process, when double-sided polishing is used, two raw substrates are sealed in the carrier by the method of nipping the transfer master as described above, and they are respectively set on the polishing platen under the double-sided polishing device. And the upper side polishing platen for processing. Generally, although the double-sided polishing device adjusts the thickness of the carrier according to the thickness of one raw substrate, the present invention considers the thickness of the two raw substrates and the transfer master, and sets the thickness of the carrier to be thicker Better. Otherwise, it can be processed without being particularly different from normal polishing processing. In this stage, each single side of the two raw substrates is processed at the same time, so the shape of the transfer master is only transferred to the single side that is in contact with the lower polishing platen and the upper polishing platen. , There is no change because the surface contacting the transfer master has not been processed.

Since the center of the transfer master is thicker than the outer periphery, the processing pressure of the raw substrate and the polishing platen is concentrated in the center of the raw substrate at the beginning of the transfer process. At this time, since the raw substrate is thin and the reaction force is small, cutting is performed selectively from the center of the raw substrate. If the cutting progresses and the processing reaches the outer periphery of the raw substrate, the shape of the final transfer master is transferred to the opposite side of the raw substrate that is not in contact with the transfer master (that is, it is in contact with the polishing platen Of the face).　　 When the outer peripheral part of the transfer master is thinner than the central part, due to the difference in thickness between the outer peripheral part and the central part, the outer peripheral part of the raw substrate obtained by the transfer process becomes thicker than the central part. Conversely, when the outer peripheral part of the transfer master is thicker than the central part, the outer peripheral part of the raw substrate obtained in the transfer process becomes thinner than the central part due to the difference in thickness between the outer peripheral part and the central part. In this way, the shape to be transferred can be created in accordance with the shape of the transfer master.

In addition, in the transfer process, when a single-sided polishing device is used, a transfer master is set between the raw substrate and the top plate of the single-sided polishing device so that the flat surface faces the top plate side, and After fixing the carrier on the top plate, the raw substrate and the transfer master do not fall off laterally, and then the raw substrate is processed. The raw substrate is processed by the polishing platen under the single-sided polishing device. As the processing progresses, the shape of the transfer master is only transferred to the surface of the polishing platen under the raw substrate.

For the transfer substrate that has undergone the above transfer process, a double-sided polishing device or a single-sided polishing device is used for polishing. The rotation speed of the double-sided polishing device and the single-sided polishing device is preferably 5~50rpm, and the load is preferably 10~200g/cm ² . When using a double-sided polishing device, set the transfer substrate so that the flat surface faces the polishing platen side of the upper side of the double-sided polishing device, and set a carrier to prevent the substrate from falling off, and perform normal polishing processing. Thereby, a polished substrate in which the upper side surface is polished into a convex shape and the lower side surface is polished into a concave shape is obtained. The SORI value of the polished substrate becomes about half of the SORI value before polishing, and the degree of reduction also depends on the diameter and thickness of the transfer substrate. The principle of making the shape of the front and back surface is based on the thickness deviation that has existed in the initial shape, and the in-plane processing pressure difference is generated from the initial stage of processing on both sides, whereby the cut part changes selectively and over time. As a result, the processing distribution within the surface of the substrate is also processed according to this change. As a result, it also depends on the reaction force of the transfer substrate, that is, the diameter and thickness of the transfer substrate, and the shape of the substrate before the original polishing process is halved, while reflecting on the shape of both sides.

In the case of using a single-sided polishing device, set the transfer substrate between the lower polishing platen and the top plate with the flat surface facing the lower polishing platen side, and set the transfer substrate in such a way that it does not fall off laterally The carrier is polished. In this case, since only the surface that has not been transferred is polished, the SORI of the transfer side surface of the original transfer platen is equivalent to the SORI of the polished substrate obtained.

In order to make the polished substrate obtained by the above-mentioned polishing process to be mirror-finished, a double-sided or single-sided polishing process is further carried out as required.　　In the grinding process, a double-sided grinding device or a single-sided grinding device can be used. The surface to be mirrored may be either a convex SORI or BOW positive surface or a concave SORI or BOW negative surface.　　In this way, in the end, various semiconductor substrates having the desired shapes (SORI and BOW) as shown in Fig. 1 can be produced.

Hereinafter, the implementation modes of the present invention will be described with reference to the drawings.　　 FIG. 5 shows an implementation aspect of the transfer process using the double-sided polishing device 1 related to the first embodiment of the present invention. In this embodiment, as shown in FIG. 5, the two raw substrates 11, 11 are enclosed in the carrier 12 in such a manner that the transfer master 10 is sandwiched, and they are installed in the double-sided polishing device. 1 Lower side polishing platen 13 and upper side polishing platen 14.

The transfer master 10 used in this embodiment, as shown in FIG. 6, has a center line L1 with respect to the center point 100A connecting the center point 100A of the surface 100 and the center point 110A of the back surface 110 of the transfer master 10 The center points 100A and 110A of the center point M1, and the imaginary plane S1 orthogonal to the center line L1, the convex SORI and the thickness deviation of the surface 100 and the back surface 110 symmetrically facing each other, which are symmetrical with respect to the center line L1 The shape of the back of the table.

Furthermore, the raw material substrate 11 used in this embodiment is produced by cutting a synthetic quartz glass ingot with a wire, performing chamfering, and removing the saw marks on the front and back by a double-sided polishing device. The diameter is 100mm, thickness 630μm, SORI on the front and back sides are 6μm, and BOW on the front and back sides are +3μm, -3μm, and the thickness deviation is 1μm.

As described above, in the state where two raw substrates 11 are installed, the rotation speed of the double-sided polishing device 1 is 20 rpm and the load is 100 g/cm ² , and the one-sided side of each raw substrate 11 is processed at the same time to obtain a transfer master. The shape of 10 is transferred to the transfer substrate on one side. Next, as shown in FIG. 7, the shape of the transfer master 10 is transferred to the single-sided transfer substrate 11A so that the flat surface faces the upper polishing platen 14 side of the double-sided polishing device 1. One piece is sealed in the carrier 12 and installed, and the double-sided polishing process is performed at a rotation speed of 20 rpm and a load of 100 g/cm ² to transfer the shape of the transfer master 10 even on the surface that has not been transferred in the transfer process By this, a polished substrate can be obtained in which the upper side surface is polished into a convex shape, and the lower side surface is polished into a concave shape.

For the obtained polished substrate, by mirroring both sides with a double-side polishing device (not shown), a SORI synthetic quartz glass substrate having a center symmetry as shown in FIG. 1(A) can be obtained. Specifically, the SORI on the surface is a convex shape of 50μm, the BOW is +25μm, the SORI on the back is a concave shape of 50μm, the BOW is -25μm, the in-plane thickness deviation is 1μm, and the thickness of 500μm on both sides is mirror-surfaced synthetic quartz Glass base board.

FIG. 8 shows the implementation aspect of the transfer process using the single-side polishing device 2 related to the second implementation aspect of the present invention. In addition, in the second embodiment, the same reference numerals are given to the same members as the above-mentioned first embodiment. As shown in FIG. 9, the transfer master 20 used in this embodiment has a center line L2 with respect to the center point 200A connecting the center point 200A of the surface 200 and the center point 210A of the back surface 210 of the transfer master 20. The middle point M2 of the center points 200A and 210A, and the imaginary plane S2 orthogonal to the center line L2, the surface 200 is parallel (flat surface), the back surface 210 is perpendicular to the center line L2, and is symmetrical with respect to the center line L2 Along the convex shape.

Furthermore, the raw substrate 21 used in this embodiment is produced in the same way as in the first embodiment. The diameter is 200mm, the thickness is 855μm, the SORI on the front and back sides is 6μm, and the thickness deviation is 1μm. Disc-shaped synthetic quartz glass substrate.

As shown in FIG. 8, it is arranged so that the flat surface of the transfer master 20 faces the top plate 25 side, and it is set to be in contact with the transfer master 20 along the convex surface. The raw substrate 21 is set in the single-sided polishing device 2, and these are enclosed in the carrier 12 at a rotation speed of 20 rpm and a load of 100 g/cm2. Only the raw substrate 21 is processed by the lower polishing platen. The contact surface of the printing master 20 obtains a transfer substrate in which the shape of the transfer master 20 is transferred to one side.

Next, as shown in FIG. 10, between the polishing platen 13 and the top plate 25 on the lower side of the single-sided polishing device 2, the shape of the transfer master 20 is transferred to the single-sided transfer substrate 21A. in the shape of the transfer of the master disk 20 is transferred to the surface side of the top plate 25 toward a state, the seal carrier 12 is provided, at a rotation of 20 rpm, load of 100g / cm ² for single-sided polishing, even for the turn In the printing process, the shape of the transfer master disk 20 is also transferred to the surface that is not transferred in the printing process, thereby obtaining a polished substrate in which the upper side surface is polished into a concave shape, and the lower side surface is polished into a convex shape.

Regarding the obtained polished substrate, as in the first embodiment, by mirroring both sides, it is possible to obtain a SORI synthetic quartz glass substrate having a center symmetry as shown in FIG. 1(A). Specifically, the surface is convex of SORI100μm, the BOW is +50μm, the back is concave of SORI110μm, and the BOW is -50μm, the in-plane thickness deviation is 1μm, and the thickness of the synthetic quartz glass substrate is 725μm on both sides with mirror surface. .

In addition, the shape, thickness and SORI of the transfer master used in the method of manufacturing a semiconductor substrate of the present invention, the shape and material of the raw substrate, and the specific conditions of each processing are not limited to the above-mentioned embodiments. Therefore, changes or improvements within the scope of achieving the purpose and effects of the invention are also included in the present invention.

For example, in the case of using a double-sided polishing device to manufacture a semiconductor substrate with non-centrosymmetric SORI, in the first embodiment described above, the transfer master 30 shown in FIG. 11 may be used. The transfer master 30 has an intermediate point M3 with respect to each of the vertices 300A and 310A in a straight line L3 passing through the apex 300A of the surface 300 and the apex 310A of the back surface 310, and a virtual plane S3 orthogonal to the straight line L3. A convex SORI with the surface 300 and the back surface 310 facing each other symmetrically. Using this transfer master 30, as in the first embodiment, by performing transfer processing, polishing processing, grinding processing, etc., it is possible to obtain the convex apex as shown in Figure 1(B) shifted from the center To the convex shape in the Y-axis direction, a semiconductor substrate with positive BOW warpage can be obtained.

Furthermore, in the case of manufacturing a semiconductor substrate with non-centrosymmetric SORI using a single-sided polishing device, it is sufficient to use the transfer master 40 shown in FIG. 12 in the above-mentioned second embodiment. The transfer master 40 has an intermediate point M4 between the vertex 410A and the partial point 400 of the straight line L4 that passes through the vertex 410A connecting the back surface 410 and the partial point 400A on the opposite surface 400, and is in line with the straight line L4. The imaginary plane S4 orthogonal to L4 has a parallel surface (flat surface) 400 on the surface, and a convex SORI on the back surface 410. Using this transfer master 40, as in the second embodiment, by performing transfer processing, polishing processing, grinding processing, etc., it is possible to obtain the convex apex as shown in FIG. 1(B) shifted from the center. To the convex shape in the Y-axis direction, a semiconductor substrate with positive BOW warpage can be obtained.

In addition, in the first embodiment described above, when the XY axis orthogonal to the surface of the transfer master as shown in FIG. 13 is provided, the thickness as viewed from the cross section in the X direction and the Y direction is used. The shape has a thickness deviation that is linearly symmetrical to the line (the Y axis in FIG. 13) that penetrates the center of the transfer master disk that is inclined differently from the center to the outer periphery in the X direction and the Y direction. In the case of a printing master, the semiconductor substrate shown in Fig. 1(C) can be obtained. In addition, the curve on the inner side of the substrate in FIG. 13 represents the contour of the thickness. [Example]

Hereinafter, although examples and comparative examples are given to explain the present invention more specifically, the present invention is not limited to the following examples.

[Example 1] As a transfer master, one having the shape shown in FIG. 6 was prepared. Specifically, the SORI for preparing the front and back sides is the same. It is a convex 110μm. Relative to the midpoint on the center line connecting the center points of the front and back sides, the front and back sides are symmetrically facing each other and the thickness is perpendicular to the center line. A master plate made of alumina ceramics with a deviation of 220μm and a center thickness of 3mm and a diameter of 100mm. In addition, a wire saw E450E-12 made by Toyo Advanced Machine Tool (Stock) was used to cut the ingot made of synthetic quartz glass and chamfered. The saw marks on the front and back were removed by the double-sided polishing device to prepare a diameter of 100mm and a thickness of 100mm. 630μm, the SORI on the front and back sides are 6μm, and the thickness deviation is 1μm. By nipping the above-mentioned transfer master plate, the two raw substrates are respectively set on the lower side polishing platen and the upper side polishing platen of the double-sided polishing device, and the polishing with the serial number #1000 alumina as the main component is used. The single-sided side of each raw substrate was processed at the same time at a rotation speed of 20 rpm and a load of 100 g/cm ^{2 to} obtain a transfer substrate in which the shape of two transfer masters was transferred to the single-sided side. The shapes of the obtained transfer substrates were all warped in a concave shape on one side by 110 μm.

In the double-side transfer substrate obtained by a polishing apparatus provided with the same engineering the transfer, a polishing material, at a rotation of 20 rpm, load of 100g / cm ² for a double-sided polishing, even if not previously transferred for engineering The surface to be transferred also transfers the shape of the transfer master. In addition, a polished substrate with a convex surface of SORI 50 μm, a BOW of +25 μm, a concave shape of SORI 50 μm on the back, and a BOW of -25 μm was obtained. In addition, as a process for polishing both sides of the substrate obtained by polishing, the double-sided device is used to mirror both sides to obtain a convex shape of SORI50μm on the surface and a BOW of +25μm, and a concave shape of SORI50μm on the back and a BOW of +25μm. , In-plane thickness deviation (TTV) is 1μm, and the thickness of 500μm is a synthetic quartz glass substrate with mirrored surfaces on both sides. Next, silane gas is supplied to the surface of the obtained synthetic quartz glass substrate to form an amorphous silicon film, and then an annealing process is performed to form a polysilicon film. After the formation of the polysilicon film, the surface of the film is changed to a convex shape of SORI 122μm, and the other surface is changed to SORI1222μm concave shape. After further heat treatment at 1050°C for one hour, the surface of the film can be changed into a convex shape of SORI 4μm and the other surface into a concave shape of SORI 4μm. The in-plane thickness deviation (TTV) is 1μm, which has an almost flat surface. SORI's synthetic quartz glass substrate for polysilicon TFT.

[Example 2] After the transfer process was performed in the same manner as in Example 1 using a double-sided polishing device, the obtained transfer substrate was set so that the surface on which the shape of the transfer master was transferred faces the single-sided polishing device On the top plate side, single-sided polishing is performed at a rotation speed of 200 rpm and a load of 100 g/cm ^{2 to obtain a polished substrate.} In addition, the two sides of the polished substrate obtained by grinding in the same manner as in Example 1, obtained a convex shape of SORI110μm on the surface and a BOW of +55μm, a concave shape of SORI 110μm on the back and a BOW of -55μm, and the thickness deviation in the plane was obtained. (TTV) is a synthetic quartz glass substrate with a thickness of 1μm and a thickness of 500μm with mirrored surfaces on both sides. Next, after forming a polysilicon film on the obtained synthetic quartz glass substrate in the same manner as in Example 1, the surface of the film was changed to a convex shape of SORI 122 μm, and the other surface was changed to a concave shape of SORI 122 μm. After further heat treatment at 1050°C for one hour, the surface of the film can be changed into a convex shape of SORI 4μm and the other surface into a concave shape of SORI 4μm. The in-plane thickness deviation (TTV) is 1μm, which has an almost flat surface. SORI's synthetic quartz glass substrate for polysilicon TFT.

[Example 3] As a transfer master, one having the shape shown in FIG. 9 was prepared. Specifically, one of the front and back surfaces is flat, and the other surface is orthogonal to the center line connecting the centers of the front and back surfaces, and is symmetrically convexly warped with a shape of 110 μm with respect to the center line, and The in-plane thickness deviation (TTV) is an alumina transfer master with a thickness of 2mm in the center of 110μm and a diameter of 200mm. As a raw material substrate, in the same manner as in Example 1, a quartz glass substrate with a diameter of 200 mm, a thickness of 855 μm, a SORI of 6 μm on the front and back sides, and a thickness deviation of 1 μm was prepared. Between the raw material substrate and the top plate of the single-sided polishing device, the transfer master plate is set so that the flat surface faces the top plate side, and the polishing material with serial number #1000 alumina as the main component is used. The number of rotations is 20 rpm, the load is 100 g/cm ² , and the one-sided side of the raw substrate is processed to obtain the transfer substrate in which the shape of the transfer master is transferred to the one-sided side. The shape of the obtained transfer substrate was flat on one side, and the other side was concavely warped by 110 μm.

Next, between the polishing platen and the top plate on the lower side of the single-sided polishing device, the transfer substrate is set so that the surface to be transferred faces the top plate side of the single-sided polishing device, and the polishing material is used in the same way as the above transfer process. One-sided processing was performed at a rotation speed of 20 rpm and a load of 100 g/cm ^{2 to obtain a polished substrate.} The obtained processed substrate was a polished substrate with a convex surface of SORI 10 μm and a concave surface of SORI 110 μm on the back surface. In addition, a single-sided polishing device was used to mirror the convex side of the surface to obtain a convex shape with a surface of SORI 110 μm and a BOW of +55 μm, a concave shape with a SORI of 110 μm on the back and a BOW of -55 μm, and the thickness deviation (TTV ) Is a synthetic quartz glass substrate with a thickness of 1μm and a thickness of 725μm. In the same manner as in Example 1, after forming a polysilicon film on the obtained synthetic quartz glass substrate, the surface of the film was changed to a convex shape of SORI 122 μm, and the other surface was changed to a concave shape of SORI 122 μm. After further heat treatment at 1050°C for one hour, the surface of the film can be changed into a convex shape of SORI 4μm and the other surface into a concave shape of SORI 4μm. The in-plane thickness deviation (TTV) is 1μm, which has an almost flat surface. SORI's synthetic quartz glass substrate for polysilicon TFT.

[Example 4] 　　 The transfer substrate obtained by the transfer process in the same manner as in Example 3 was subjected to double-sided polishing in the same method as in Example 1, to obtain a convex shape of SORI 50 μm on the surface and 150 μm on the back surface. Concave polished substrate. In addition, both sides were polished in the same manner as in Example 1, to obtain a convex shape of SORI150μm on the surface and a BOW of +25μm, a concave shape of SORI50μm on the back and a BOW of -25μm, a thickness deviation of 1μm and a thickness of 725μm. It is a synthetic quartz glass substrate with a mirror surface. "In the same manner as in Example 1, after forming a polysilicon film on the obtained synthetic quartz glass substrate, the surface of the film was changed to a convex shape of SORI 122 μm, and the other surface was changed to a concave shape of SORI 122 μm. After further heat treatment at 1050°C for one hour, the surface of the film can be changed to a convex shape of SORI 4μm, and the other surface is changed to a concave shape of SORI 4μm. The thickness deviation (TTV) is 1μm, with almost flat SORI. Synthetic quartz glass substrate for polysilicon TFT.

[Example 5] As a master for transfer, a shape as shown in FIG. 11 was prepared. Specifically, the shape of the front and back is prepared to be mutually symmetrical convex shapes. The SORI is 110 μm, and the in-plane thickness deviation (TTV) is 220 μm. A alumina ceramic transfer master with a thickness of 3000 μm and a diameter of 100 mm.　　 As a raw substrate, a synthetic quartz glass substrate with a diameter of 100 mm, a thickness of 630 μm, a SORI of 6 μm on the front and back sides, and an in-plane thickness deviation (TTV) of 1 μm were prepared in the same manner as in Example 1. "In the same method as in Example 1, the single-sided side of two raw substrates was processed simultaneously by a double-sided polishing device to obtain a transfer substrate in which the shape of the transfer master was transferred to the single-sided side. The shapes of the obtained transfer substrates were all warped in a concave shape on one side by 110 μm. Furthermore, the thinnest part of the concave shape is offset by 30 mm from the center.

The obtained transfer substrate was set in the double-sided polishing device, and the double-sided polishing process was performed in the same way as in Example 1. Even for the surface that was not transferred in the previous transfer process, the transfer master was also transferred. The shape is a polished substrate with a convex shape of SORI 50 μm on the surface and a concave shape of SORI 50 μm on the back surface. In addition, the convex side surface of the polished substrate obtained was mirror-finished with a single-sided polishing device, and the mirror surface was convex with SORI150μm and the BOW was +20μm, and the rough surface was concave with SORI50μm and the BOW was -20μm. Synthetic quartz glass substrate with inner thickness deviation (TTV) of 1μm and thickness of 500μm.　　 Next, after forming a polysilicon film on the surface of the obtained synthetic quartz glass substrate in the same manner as in Example 1, the surface of the film was changed to a convex shape of SORI 122 μm, and the other surface was changed to a concave shape of SORI 122 μm. After further heat treatment at 1100°C for two hours, the surface of the film can be changed to a convex shape of SORI 4μm, and the other surface is changed to a concave shape of SORI 4μm. The thickness deviation is 1μm, and it is used for polysilicon TFT with almost flat SORI. Synthetic quartz glass substrate.

[Example 6] 　　 As in Example 5, one of the front and back surfaces is flat, and the other surface is convexly warped 110μm, and the in-plane deviation (TTV) is 220μm, from the front and back The thickness is the thickest where the center point is offset by 30mm. The thickness of the part is 3000μm and the diameter of 100mm is alumina ceramic transfer master. ""As a raw material substrate, the same as that of Example 5 was prepared. "In the same way as in Example 3, the one-sided side of the raw substrate was processed by a single-sided polishing device to obtain a transfer substrate in which the shape of the transfer master was transferred to the one-sided side. The shape of the obtained transfer substrate was flat on one side, and the other side was concavely warped by 110 μm. Furthermore, the thinnest part of the concave shape is offset by 30 mm from the center. The transfer substrate obtained by setting the single-sided polishing device and the one-sided polishing process was performed in the same manner as in Example 2. Even if the transfer substrate was not transferred in the transfer process, the surface on the opposite side of the transfer substrate was also transferred. The shape of the transfer master is a polished substrate with a convex surface of SORI 110 μm and a concave surface of SORI 110 μm on the back surface. The convex side surface of the polished substrate obtained was mirror-finished with a single-sided polishing device, and the mirror surface was convex with SORI 110 μm and the BOW was +50 μm, the rough surface was concave with SORI of 110 μm and the BOW was -50 μm. Synthetic quartz glass substrate with inner thickness deviation (TTV) of 1μm and thickness of 500μm.　　 Next, after forming a polysilicon film on the surface of the obtained synthetic quartz glass substrate in the same manner as in Example 1, the surface of the film was changed to a convex shape of SORI 122 μm, and the other surface was changed to a concave shape of SORI 122 μm. After further heat treatment at 1100°C for two hours, the surface of the film can be changed to a convex shape of SORI 4μm, and the other surface is changed to a concave shape of SORI 4μm. The in-plane thickness deviation is 1μm, and it has almost flat SORI polycrystalline silicon. Synthetic quartz glass substrate for TFT.

[Comparative Example 1] 　　 As a transfer master, prepare the SORI of 110μm on the front and back, one side is convex, the other side is concave, the thickness is 2mm, the thickness deviation is 2μm and the diameter is 100mm. A transfer master was prepared, and as a raw substrate, the same as in Example 1 was prepared.　　Using a double-sided polishing device, the raw substrate was subjected to transfer processing in the same manner as in Example 1, to obtain a transfer substrate with a SORI of 1 μm on the front and back sides. In addition, the obtained transfer substrate was mirror-finished on both sides with a double-sided polishing device, and the SORI of the front and back was 1μm and the BOW of the surface was +0.5μm. The BOW of the back was -0.5μm, and the in-plane thickness deviation (TTV) was 1μm, 500μm thick synthetic quartz glass substrate with mirrored surfaces on both sides. "In the same way as in Example 1, after forming a polysilicon film on the obtained synthetic quartz glass substrate, the surface of the film was changed to a convex shape of SORI 120 μm, and the other surface was changed to a concave shape of SORI 120 μm. After further heat treatment at 1050°C for one hour, the in-plane thickness deviation (TTV) remained as it was 1μm, the surface of the film was changed into a convex shape of SORI 60μm, and the other surface was changed into a concave shape of SORI 61μm, which failed to achieve the expected Flat SORI.

[Comparative Example 2] As a transfer master, prepare the SORI of 110μm on the front and back, convex on one side, concave on the other, thickness deviation (TTV) of 1μm, thickness of 2mm, and diameter of 200mm The alumina transfer master was prepared as the raw material substrate, which was the same as in Example 4. After the transfer process was performed on the raw substrate using a single-sided polishing device in the same manner as in Example 4, the obtained transfer substrate was polished ^{with a double-sided polishing device at a rotation speed of 20 rpm and a load of 100 g/cm 2 to obtain} The SORI on the front and back is a polished substrate of 1μm. In addition, double-sided grinding of the obtained polished substrate was performed to obtain a SORI of 1μm on the front and back, a BOW of +0.5μm on the surface, a BOW of -0.5μm on the back, a thickness deviation (TTV) of 1μm, and a thickness of 725μm. Synthetic quartz glass substrate. In the same manner as in Example 1, after forming a polysilicon film on the obtained synthetic quartz glass substrate, the in-plane thickness deviation (TTV) was maintained at 1 μm, and the surface of the film was changed to a convex shape of SORI 120 μm, and the other surface was changed to SORI 120μm concave shape. After further heat treatment at 1050°C for one hour, the in-plane thickness deviation (TTV) was as it was 1μm. The surface of the film was changed to a convex shape of SORI 60μm, and the other surface was changed to a concave shape of SORI 61μm. The expected result was not obtained. Flat SORI.

[Comparative Example 3] 　　 As a transfer master, the SORI of the front and back is 110μm, one side is convex, the other side is concave, the in-plane thickness deviation (TTV) is 1μm, the thickness is 2mm, and the diameter is 110mm The alumina transfer master was prepared as the raw material substrate, which was the same as in Example 2. In the same manner as in Example 2, after the transfer process was performed on the raw substrate using the double-sided polishing device, the flat surface of the transfer master plate without being transferred was set to face the top plate side of the single-sided polishing device. The transfer substrate was polished under the same conditions as in Example 2 to obtain a polished substrate with a surface SORI of 1 μm. In addition, the single side of the polished substrate obtained was mirror-finished with a single-side polishing device, and the SORI of the surface was 1μm and the BOW of the surface was +0.5μm, the BOW of the back was -0.5μm, and the in-plane thickness deviation (TTV) was 1μm, 500μm thick synthetic quartz glass substrate. "In the same method as in Example 1, after forming a polysilicon film on the obtained synthetic quartz glass substrate, the surface of the film was changed to a convex shape of SORI 120 μm, and the other surface was changed to a concave shape of SORI 120 μm. After further heat treatment at 1050°C for one hour, the in-plane thickness deviation (TTV) was as it was 1μm. The surface of the film was changed to a convex shape of SORI 60μm, and the other surface was changed to a concave shape of SORI 61μm. The expected result was not obtained. Flat SORI.

[Comparative example 4] 　　 As a transfer master, the SORI of the front and back is 110μm, one side is convex, the other side is concave, the in-plane thickness deviation (TTV) is 1μm, the thickness is 2mm, and the diameter is 200mm The alumina transfer master was prepared as the raw material substrate, which was the same as in Example 4. In the same manner as in Example 4, after the transfer process of the raw substrate was carried out using the single-sided polishing device, set it so that the flat surface of the transfer master without being transferred faces the top plate side of the single-sided polishing device The transfer substrate was polished under the same conditions as in Example 2 to obtain a polished substrate with a surface SORI of 1 μm. In addition, the single side of the polished substrate obtained was mirror-finished with a single-side polishing device, and the SORI of the surface was 1μm and the BOW of the surface was +0.5μm, the BOW of the back was -0.5μm, and the in-plane thickness deviation (TTV) was Synthetic quartz glass substrate with a thickness of 1μm and a thickness of 725μm. "In the same way as in Example 1, after forming a polysilicon film on the obtained synthetic quartz glass substrate, the surface of the film was changed to a convex shape of SORI 120 μm, and the other surface was changed to a concave shape of SORI 120 μm. After 　　, after further heat treatment at 1050°C for one hour, the in-plane thickness deviation remained as it was 1μm, the film formed surface changed to a convex shape of SORI 60μm, and the other surface changed to a concave shape of SORI 61μm, and the expected flat SORI could not be obtained.

Table 1 shows the conclusions of the above-mentioned Examples and Comparative Examples.

A‧‧‧Semiconductor substrate 1‧‧‧Double-side polishing device 2 Single-side polishing device 10, 20, 30, 40‧‧‧ Transfer master 11A, 21A‧‧‧Transfer substrate 100, 200, 300, 400‧‧‧The surface of the transfer master plate 110, 210, 310, 410‧‧‧The back of the transfer master plate 100A, 110A, 200A, 210A‧‧‧Center point L1, L2‧‧‧Center point S1 S2, S3, S4‧‧‧Imaginary surface (surface orthogonal to the center line) 11, 21‧‧‧Material substrate

Figure 1 shows the state of SORI of the semiconductor substrate of the present invention. (A) shows the state where the center is symmetrically warped into a convex shape, and (B) shows the state where the apex of the warped convex shape is shifted from the center to the Y-axis direction The state of convexity, (C) represents the state of being warped into a convex shape of line symmetry. In addition, the curve inside the surface represents the contour line of the display height. 2 is an explanatory diagram of the SORI of the semiconductor substrate of the present invention, S represents the least square plane, a represents the minimum distance between the surface S and the surface of the semiconductor substrate A, and b represents the difference between the surface S and the surface of the semiconductor substrate A The maximum value of the distance. 3 is an explanatory diagram of the BOW of the semiconductor substrate of the present invention, e represents the middle surface of the front and back, S2 represents the reference plane obtained from e, and f represents the center line of the substrate, so that in the distance between S2 and e intersecting with f, If e is higher than S2, it is marked with +d, if it is lower than S2, it is marked with -d. For those marked with d, it is defined as BOW.　　 FIG. 4 is a graph showing the thickness deviation c of the semiconductor substrate of the present invention.　　 FIG. 5 is a schematic diagram showing a transfer process using a double-sided polishing device related to the first embodiment of the present invention.　　 Fig. 6 is a side view showing a transfer master with a center symmetry of SORI used in the first embodiment.　　 Figure 7 shows a schematic diagram of a polishing process using a double-sided polishing device related to the first embodiment.　　 FIG. 8 is a schematic diagram of a transfer process using a single-sided polishing device related to the second embodiment of the present invention.　　 FIG. 9 is a side view showing a transfer master with a center symmetry of SORI used in the second embodiment.　　 Figure 10 shows a schematic diagram of a polishing process using a single-side polishing device related to the second embodiment.　　 FIG. 11 is a side view showing a transfer master with non-centrosymmetric SORI related to a modification of the first embodiment.　　 Fig. 12 is a side view showing a transfer master with non-centrosymmetric SORI related to a modification of the second embodiment.　　 FIG. 13 is a top view and a side view showing a transfer master disk related to another modification of the first embodiment.

Claims (9)

A semiconductor substrate characterized by having one surface with convex SORI and the other surface with concave SORI of the same degree as the above-mentioned SORI, and a thickness deviation of 3μm or less, made of synthetic quartz glass . As for the semiconductor substrate set forth in claim 1, the SORI of each of the above-mentioned sides is 50~600μm. For the semiconductor substrate set forth in claim 1 or 2, the BOW of one of the above-mentioned convex SORI faces is +25~+300. For the semiconductor substrate set forth in claim 1 or 2, the BOW of the other side of the SORI having the above-mentioned concave shape is -25 to -300. Such as the semiconductor substrate set forth in claim 1 or 2, wherein the thickness is 0.5~3mm. The semiconductor substrate set forth in claim 1 or 2, wherein the shape of the semiconductor substrate is a circular shape with a diameter of 100 to 450 mm or a rectangular shape with a diagonal length of 100 to 450 mm in a plan view. The semiconductor substrate described in claim 1 or 2 is a polysilicon TFT substrate. A method for manufacturing a semiconductor substrate, comprising: a preparation process of preparing a transfer master disk, and the transfer master disk has a surface and a back surface, and has a center point that connects the front and back surfaces. The middle point on the center line of the above, the plane orthogonal to the above center line, the SORI and the thickness deviation of the above surface and back side symmetrically; The polishing device is equipped with two raw substrates, and processes the surfaces of the raw substrates that are not in contact with the transfer master to produce the two transfer masters whose shape is transferred to each single side Transfer substrate; polishing process, which is by polishing both sides of the transfer substrate, or by polishing only the surface of the transfer substrate that has not been transferred with the shape of the transfer master in the transfer process To make a polished substrate; and grind both sides or one side of the polished substrate. A method of manufacturing a semiconductor substrate, comprising: a preparation process of preparing a transfer master disk, and the transfer master disk has a surface and a back surface. The middle point on the center line is the surface orthogonal to the center line, the front and back surfaces are parallel to each other, and the other surface of the front and back surfaces that is in contact with the raw substrate is orthogonal to the center line , And at the same time relative to the above The center line is symmetrical; the transfer process involves setting a raw substrate in a single-sided polishing device in such a way that it is in contact with the other side of the transfer master. The mating surfaces of the master are processed to produce a transfer substrate in which the shape of the above-mentioned transfer master is transferred to a single side; the polishing process is performed by polishing both sides of the above-mentioned transfer substrate, or by only polishing In the transfer substrate, a polished substrate is produced on the surface on which the shape of the transfer master is not transferred in the transfer process; and both sides or one side of the polished substrate are polished.

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