JP5814719B2 - Substrate manufacturing method, mask blank manufacturing method, transfer mask manufacturing method, and correction carrier - Google Patents

Description

  The present invention relates to a substrate manufacturing method, a mask blank manufacturing method, a transfer mask manufacturing method, a correction carrier, and the like.

The shape accuracy (flatness) required for a mask blank substrate has become severe due to the recent increase in density and accuracy of VLSI devices, and an ultrahigh flatness mask blank substrate is required.
Conventionally, in a grinding process of a mask blank glass substrate, a glass substrate held by a carrier is sandwiched at a predetermined pressure between two cast iron surface plates each having a grid-like groove on the surface, and a grinding liquid containing free abrasive grains While supplying (slurry) between the glass substrate and the surface plate, the glass substrate is caused to perform a planetary motion on the surface plate, whereby grinding (lapping) of both main surfaces of the substrate is performed. However, the flatness of the surface plate surface deteriorates as the number of processing batches increases due to the fact that the surface of the surface plate itself can be cut during grinding. For this reason, every time a predetermined number of batches are processed, the correction carrier (correction member is made of cast iron), which is a correction carrier, is used as a planet on the surface plate in the same manner as in the grinding process. The flatness of the surface plate is corrected by moving it.
On the other hand, in the grinding process of the glass substrate for magnetic disks, in recent years, a double-side grinding apparatus in which fixed abrasive grains containing diamond particles are arranged on the grinding surface of a surface plate has been used. Even when using a surface plate in which fixed abrasive grains containing diamond particles are arranged on the grinding surface, the flatness of the fixed abrasive particles (grind surface) of the surface plate due to an increase in the number of processing batches is unavoidable. For each number, the flatness of the surface plate surface is corrected by using a correction carrier and sequentially using metal and glass as correction members (Patent Document 1).

JP 2008-254166 A

In recent years, the use of a double-sided grinding apparatus in which fixed abrasive grains containing diamond particles are arranged on the grinding surface of a surface plate has also been studied in the grinding process of the mask blank substrate.
The present invention is suitable for use in a grinding process or the like in which a fixed abrasive such as a fixed abrasive containing diamond particles is provided on a grinding surface of a surface plate in a grinding process of a glass substrate such as a mask blank substrate. An object is to provide a method for manufacturing a substrate.

As a result of intensive studies, the present inventors have found the following.
As disclosed in Patent Document 1, in consideration of problems such as rotational friction force, the correction carrier has a configuration in which the correction member is arranged only on the outer peripheral side of the correction carrier main body (for example, in the ring-shaped correction carrier main body). In general, a plurality of correction members are arranged.
However, if the overhang amount of the correction member relative to the fixed abrasive (grind surface) of the surface plate is excessively large, the correction member is disposed only on the outer peripheral side of the carrier, or the correction carrier is moved in a planetary motion. It has been found that problems arise due to the modification of the fixed abrasive grains (grinding surface). Specifically, as shown in FIG. 8, when the overhang amount of the correction member 53 with respect to the fixed abrasive grains (grinding surface) 11 of the surface plate 10 is excessively large, the correction member 53 is once fixed on the surface plate. (Grinding surface) After jumping out from the outer peripheral end portion 11a of the surface 11, draw a trajectory that enters the fixed abrasive (grinding surface) 11 of the surface plate 10 from the outer peripheral end portion 11a side again. become. When the correction member 53 enters from the outer peripheral end portion 11a side toward the fixed abrasive grains (grinding surface) 11 of the surface plate 10, the fixed abrasive grains (grinding surface) 11 on the outer peripheral end portion 11a side is changed. The surface of the surface plate 10 may be cut more than necessary, which may hinder the improvement of the flatness correction of the fixed abrasive grains (grinding surface) 11 of the surface plate 10 (for example, the surface plate has a radius of about 800 mm and the surface plate surface has a flatness of 35 μm. The inventor has found that it can only be corrected to a certain extent). After the correction member 53 has once jumped out (inner peripheral side) from the inner peripheral end 11b of the fixed abrasive grains (grinding surface) 11 of the surface plate 10, the fixing of the surface plate 10 is again performed from the inner peripheral end 11b side. The same applies to a case where a trajectory entering the abrasive grains (grinding surface) 11 is drawn.
Further, as shown in FIG. 5, in an arbitrary radial direction on the surface plate 10, the outer peripheral end portion 53 a of the correction member 53 of the correction carrier 51 is the outer peripheral end portion 11 a of the fixed abrasive (grinding surface) 11 of the surface plate 10. And the inner peripheral end 53b of the correction member 53 of the correction carrier 51 is positioned closer to the inner peripheral side than the outer peripheral end 11a of the fixed abrasive grains (grinding surface) 11 of the surface plate 10. The correction member 53 is overhanged on the outer peripheral side of the platen 10, and the outer peripheral end 53 a of the correction member 53 of the correction carrier 51 is inward of the inner peripheral end 11 b of the fixed abrasive (grinding surface) 11 of the surface plate 10. The surface plate 10 is arranged so that the inner peripheral end portion 53b of the correction member 53 of the correction carrier 51 is on the outer peripheral side of the inner peripheral end portion 11b of the fixed abrasive grains (grinding surface) 11 of the surface plate 10 along the peripheral side. Overhang the correction member 53 on the inner circumference side Thus, by correcting the flatness of the fixed abrasive grains (grinding surface) 11 of the surface plate 10, the accuracy of the flatness correction of the fixed abrasive grains (grinding surface) 11 of the surface plate 10 can be greatly improved (for example, the surface plate). The present inventor has found that the radius of the plate is approximately 800 mm and the flatness of the surface plate surface can be reduced to about 20 μm or less, and has filed an application (Japanese Patent Application No. 2011-67476).

On the other hand, the flatness of the fixed abrasive on the surface plate is applied by using the above-described technique for optimizing the overhang amount of the correction member with respect to the fixed abrasive (grind surface) of the surface plate using the above-described correction carrier. It has been found that even if the correction is performed, the shape may be corrected to a convex shape (very small) from the outer peripheral edge side and the inner peripheral edge side toward the central side as viewed in the radial direction of the surface plate (lower surface plate). If the fixed abrasive on the surface plate is modified to such a convex shape, the flatness of the surface grinding surface of the surface plate cannot be further improved. It was found that it could not be further improved, which would be a problem.
The problem that the fixed abrasive on the surface plate is corrected to a convex shape (very small) is that the overhang amount of the correction member is excessively large relative to the fixed abrasive (grind surface) of the surface plate Since the absolute value of the flatness of the surface plate surface was too large, it was not manifested.

The present invention has the following configuration.
(Configuration 1)
A method for manufacturing a substrate, comprising a grinding step in which two main surfaces of a glass substrate are ground on both sides using a grinding apparatus having an upper surface plate and a lower surface plate in which fixed abrasive grains are arranged on a grinding surface,
A correction step of revolving a correction carrier having a correction member while rotating on the surface plate, and correcting the surface of the surface plate by pressing the correction member of the correction carrier and the ground surface of the surface plate against each other and sliding. Have
The correction carrier is composed of a main body portion having two opposing surfaces respectively facing the upper surface plate and the lower surface plate, and correction members respectively disposed on the two opposite surfaces,
The correction member is disposed along the outer peripheral side of the opposing surface, and is also disposed on the opposing surface on a straight line connecting the rotation axis of the correction carrier and a specific point on the outer peripheral side. Method.
(Configuration 2)
The correction member is also disposed on a straight line connecting the specific point and the rotation axis, the straight line extending from the specific point to a point on the outer peripheral side opposite to the rotation axis. The manufacturing method of the board | substrate of the structure 1.
(Configuration 3)
The substrate manufacturing method according to Configuration 1 or 2, wherein the surface plate has fixed abrasive grains including diamond particles arranged on a grinding surface.
(Configuration 4)
4. The method for manufacturing a substrate according to any one of configurations 1 to 3, wherein the correction member is configured by providing fixed abrasive grains including diamond particles.
(Configuration 5)
Any one of the constitutions 1 to 4, wherein the correction step is performed by pressing and sliding the correction member and the grinding surface of the surface plate while supplying a grinding liquid containing loose abrasive grains. A method for manufacturing the substrate according to claim 1.
(Configuration 6)
6. The method of manufacturing a substrate according to any one of configurations 1 to 5, wherein the correcting step is performed subsequent to a fixed abrasive grain arranging step of arranging fixed abrasive grains on a ground surface of a surface plate.
(Configuration 7)
The correction carrier is provided with an outer gear on the outer periphery of the main body, and the correction gear on the surface plate is formed by engaging the outer gear with both gears between the sun gear and the internal gear of the grinding device. 7. The method for manufacturing a substrate according to any one of configurations 1 to 6, wherein the substrate revolves while rotating.
(Configuration 8)
A method for producing a mask blank, comprising: forming a thin film for forming a transfer pattern on a main surface of a substrate produced by the method for producing a substrate according to any one of Structures 1 to 7.
(Configuration 9)
A method for producing a transfer mask, comprising: patterning the thin film in a mask blank produced by the method for producing a mask blank according to Configuration 8 to form a transfer pattern.
(Configuration 10)
For a grinding apparatus having an upper surface plate and a lower surface plate in which fixed abrasive grains are arranged on a grinding surface, a correction carrier used when correcting the surface of the surface plate,
An outer gear provided on the outer periphery to mesh with both gears between the sun gear and the internal gear of the grinding device, and a main body having two opposing surfaces respectively facing the upper surface plate and the lower surface plate;
A correction member disposed on each of the two opposing surfaces,
The correction carrier is arranged along the outer peripheral side of the opposing surface, and is also arranged on the opposing surface on a straight line connecting the rotation axis of the correction carrier and a specific point on the outer peripheral side.
(Configuration 11)
The correction member is also disposed on a straight line connecting the specific point and the rotation axis, the straight line extending from the specific point to a point on the outer peripheral side opposite to the rotation axis. The correction carrier according to Configuration 10.
(Configuration 12)
The correction carrier according to Configuration 10 or 11, wherein the correction member is configured by disposing fixed abrasive grains including diamond particles.

According to the present invention, in addition to arranging the correction member on the correction carrier along the outer peripheral side of the correction carrier, the following effects can be obtained by arranging the correction member also in the radius or diameter direction of the correction carrier. .
(1) Since the correction rate on the center side in the radial direction of the surface plate is faster than the outer peripheral edge side and the inner peripheral edge side in the radial direction of the surface plate, the correction amount on the central side is relatively large, and the central side is convex. It is possible to suppress the phenomenon that is corrected.
(2) If the correction member is arranged on the entire surface of the correction carrier, the frictional force between the correction member and the fixed abrasive on the surface plate becomes excessive, and the load on the apparatus increases. Can be suppressed.
(3) When the correction member is arranged only on the outer periphery of the correction carrier and the flatness correction of the fixed abrasive grains (surface plate surface) on the surface plate is advanced, the distance between each grinding surface of the upper surface plate and the lower surface plate is increased. The same phenomenon occurs. If the distance between the ground surfaces of the upper surface plate and the lower surface plate is the same, the correction rate on the surface plate becomes the same in the surface, and a phenomenon that the tendency of the convex shape cannot be corrected occurs. However, even in this case, by applying the correction carrier of the present invention, the correction rate on the center side in the radial direction of the surface plate becomes relatively fast, so that the shape can be corrected.
According to the present invention, even when the surface plate is provided with fixed abrasive grains such as fixed abrasive grains containing diamond particles on the grinding surface, the above effect can be obtained.

It is a typical top view for demonstrating the structure of the grinding / polishing apparatus of a general planetary gear system. It is a typical sectional view for explaining composition of a general planetary gear system grinding and polisher. It is a schematic plan view which shows the example of the correction carrier and correction member which are used for embodiment of this invention. It is a typical fragmentary sectional view which shows the example of the correction carrier and correction member which are used for embodiment of this invention. It is a schematic plan view which shows the example of the correction carrier and correction member which are used by a comparative example. It is a typical fragmentary sectional view which shows the example of the correction carrier and correction member which are used by a comparative example. It is a typical top view which shows the measurement position of the grinding surface in an Example and a comparative example. It is a schematic plan view which shows the example of the correction carrier and correction member which are used by a reference example. It is a graph which shows the cross-sectional profile of the upper surface plate immediately after bonding a diamond sheet. It is a graph which shows the cross-sectional profile of the lower surface plate immediately after bonding a diamond sheet. It is a graph which shows the cross-sectional profile of the upper surface plate after correction | amendment with the correction | amendment carrier of an Example. It is a graph which shows the cross-sectional profile of the lower surface plate after correction | amendment with the correction | amendment carrier of an Example. It is a graph which shows the cross-sectional profile of the upper surface plate after correction with the correction carrier of a comparative example. It is a graph which shows the cross-sectional profile of the lower surface plate after correction | amendment with the correction | amendment carrier of a comparative example.

Hereinafter, the present invention will be described in detail.
The substrate manufacturing method of the present invention is a substrate manufacturing method including a grinding step in which two main surfaces of a glass substrate are ground on both sides using a grinding apparatus having an upper surface plate and a lower surface plate in which fixed abrasive grains are arranged on a grinding surface. A method,
A correction step of revolving a correction carrier having a correction member while rotating on the surface plate, and correcting the surface of the surface plate by pressing the correction member of the correction carrier and the ground surface of the surface plate against each other and sliding. Have
The correction carrier is composed of a main body portion having two opposing surfaces respectively facing the upper surface plate and the lower surface plate, and correction members respectively disposed on the two opposite surfaces,
The correction member is arranged along the outer peripheral side of the opposing surface, and is also arranged on the opposing surface on a straight line connecting the rotation axis of the correction carrier and a specific point on the outer peripheral side (Configuration 1). ).
According to the above configuration, in addition to arranging the correction member on the correction carrier along the outer peripheral side of the correction carrier, the following effects can be obtained by arranging the correction member also in the radius or diameter direction of the correction carrier. .
(1) Since the correction rate on the center side in the radial direction of the surface plate is faster than the outer peripheral edge side and the inner peripheral edge side in the radial direction of the surface plate, the correction amount on the central side is relatively large, and the central side is convex. It is possible to suppress the phenomenon that is corrected.
(2) If the correction member is arranged on the entire surface of the correction carrier, the frictional force between the correction member and the fixed abrasive on the surface plate becomes excessive, and the load on the apparatus increases. Can be suppressed.
(3) When the correction member is arranged only on the outer periphery of the correction carrier and the flatness correction of the fixed abrasive grains (surface plate surface) on the surface plate is advanced, the distance between each grinding surface of the upper surface plate and the lower surface plate is increased. The same phenomenon occurs. If the distance between the ground surfaces of the upper surface plate and the lower surface plate is the same, the correction rate on the surface plate becomes the same in the surface, and a phenomenon that the tendency of the convex shape cannot be corrected occurs. However, even in this case, by applying the correction carrier of the present invention, the correction rate on the center side in the radial direction of the surface plate becomes relatively fast, so that the shape can be corrected.
In the present invention, the effect can be obtained even when the surface plate is provided with fixed abrasive grains such as fixed abrasive grains containing diamond particles on the grinding surface.
Further, according to the present invention, the accuracy of the flatness correction of the fixed abrasive grains (grinding surface) of the surface plate can be calculated by a numerical value (specifically, fixed abrasive grains (grinding of the upper and lower surface plates in the radial direction of the surface plate). The height difference when the length from the inner peripheral end portion to the outer peripheral end portion of the surface) is about 540 mm can be improved more than about 20 μm. For example, the accuracy of flatness correction when the length from the inner peripheral end portion to the outer peripheral end portion of the fixed abrasive grains (grinding surfaces) of the upper and lower surface plates in the radial direction of the surface plate is about 540 mm, The height difference from the inner peripheral end to the outer peripheral end of the (grinding surface) can be improved to about 15 μm.
The present invention is suitable when a grinding apparatus having a surface plate radius of greater than about 1100 mm is used.

In the present invention, the straight line connecting the rotation axis of the correction carrier and the specific point on the outer peripheral side is, for example, an arbitrary point on the straight line passing through the rotation axis (center) of the correction carrier and extending toward the outer peripheral side of the correction carrier. On a straight line connecting For example, it is on a straight line passing through the rotation axis (center) of the correction carrier and connecting an arbitrary point on the radius of the correction carrier.
In the present invention, in addition to arranging the correction member along the outer peripheral side of the correction carrier, the region including the straight line or the radius or a part of the radius on the rotation axis (center) side rather than the outer peripheral side is included. A correction member can be placed in the region.

In the present invention, the correction member is also arranged on a straight line that connects the specific point and the rotation axis to a point on the outer peripheral side opposite to the specific point with the rotation axis interposed therebetween. (Configuration 2).
In the present invention, for example, the correction member can be arranged in at least one diametric direction of the correction carrier.
In the present invention, correction members can be arranged in a plurality of diametrical directions in the correction carrier. For example, the correction member can be arranged in the cross direction (two directions that form 90 degrees with each other).
In the present invention, a correction member can be arranged in a region including the straight line or a region including the diameter or a part of the diameter.

In the present invention, from the viewpoint of avoiding that the frictional resistance of the correction member becomes too large and the correction member (correction carrier) becomes relatively inoperable with respect to the surface plate, from the viewpoint of ensuring good fluidity such as slurry, It is preferable that the correction member is intermittently disposed on the outer peripheral portion (outer peripheral portion) of the main body of the correction carrier.
In the present invention, the correction member can be arranged on the outer peripheral portion (outer peripheral portion) of the main body portion of the correction carrier at equal distances from the center of the correction carrier and at equal intervals. In this case, the plurality of correction members can have the same shape. The plurality of correction members may have different shapes.
In the present invention, the shape of the correction member may be a circle, a sector, a rectangle, a square, a substantially square whose corners are trimmed, a sector whose corners are trimmed, a rectangle whose corners are trimmed, or a square whose corners are trimmed. Other arbitrary shapes can be mentioned. The same applies to each correction member in the plurality of correction members.
In the present invention, the correction member can be formed on the entire surface (diameter portion) in the diameter direction of the main body portion of the correction carrier.
In the present invention, the correction member may be partially formed in a diametrical region (diameter portion) in the main body of the correction carrier.

In the present invention, the correction member is arranged on both the lower surface plate side and the upper surface plate side in the main body portion of the correction carrier.
The fixed abrasive grains (grinding surfaces) of the upper and lower surface plates in the double-sided grinding apparatus can be flattened simultaneously, and the correction accuracy of the fixed abrasive grains (grinding surfaces) of the upper and lower surface plates can be improved as compared with the case of correcting one by one.
In the present invention, in the correction step, the correction carrier is sandwiched between the grinding surfaces of the upper and lower surface plates, and the correction member of the correction carrier is pressed against both grinding surfaces of the upper and lower surface plates. The surface of the two upper and lower surface plates is corrected by sliding.
In the present invention, the correction member can be arranged on either the lower surface plate side or the upper surface plate side in the main body of the correction carrier. In this case, the surface of only one of the lower surface plate side and the upper surface plate side is corrected.

In the present invention, the outer peripheral end and the inner peripheral end of the fixed abrasive grains (grinding surface) of the surface plate are preferably arranged on the circumference of an equal distance (radius) from the center of the surface plate.
In the present invention, the fixed abrasive grains are obtained by fixing a large number of abrasive grains with an appropriate binder.
In the present invention, the abrasive grains (particles) constituting the fixed abrasive grains on the surface plate include abrasive grains (particles) such as diamond, CBN (cubic boron nitride), silicon carbide, and alumina.
In the present invention, the fixed abrasive on the surface plate may be any one as long as it exhibits an action (for example, a grinding action) equivalent to that of the surface plate provided with the fixed abrasive containing diamond particles.

In the present invention, the surface plate is preferably provided with fixed abrasive grains containing diamond particles on the grinding surface (Configuration 3).
In the present invention, examples of the fixed abrasive grains containing diamond particles include diamond pellets and diamond sheets.
Diamond pellets are diamond abrasive grains (particles) consolidated with resin (resin bond), metal (metal bond), and clay-like binder (vitrified bond). is there. A plurality of these pellets are used on a surface plate with an adhesive.
The diamond sheet is obtained by further solidifying abrasive grains made of glass with glass with resin (resin bond) to form a sheet.
In the present invention, the diamond abrasive grains (particles) constituting the fixed abrasive on the surface plate are preferably about # 1000 to # 4000, more preferably about # 3000 (for example, # 2900 to # 3100).

In the present invention, it is preferable that the correction member is configured by disposing fixed abrasive grains including diamond particles (Configuration 4).
Compared to the case of using other fixed abrasive grains, the calculated numerical value (for example, fixed abrasive grains (grinding of upper and lower surface plates in the radial direction of the surface plate) (grinding) The flatness of the grinding surface when the length from the inner peripheral end to the outer peripheral end of the surface is about 540 mm can be achieved. Also, the processing time is relatively shortened.
In the correction member, examples of the fixed abrasive grains containing diamond particles include diamond pellets and diamond sheets.
Diamond pellets are diamond abrasive grains (particles) consolidated with resin (resin bond), metal (metal bond), and clay-like binder (vitrified bond). is there. A plurality of these pellets are used on a surface plate with an adhesive.
The diamond sheet is obtained by further solidifying abrasive grains made of glass with glass with resin (resin bond) to form a sheet.
In the correction member, the diamond abrasive grains (particles) constituting the fixed abrasive grains preferably have a particle size of about # 1000 to # 4000, and more preferably about # 3000 (for example, # 2900 to # 3100).
In the present invention, the correction member may be made of synthetic quartz, a metal material, or the like. In this case, as compared with the case where the correction member is composed of fixed abrasive grains containing diamond particles, the grinding rate is lowered and the correction time is lengthened.
In the present invention, the correction member may be any member as long as it can correct the grinding surface of the surface plate provided with fixed abrasive grains including diamond particles.

In the present invention, the correction step is preferably performed by pressing the sliding member and the grinding surface of the surface plate against each other while supplying a grinding fluid containing loose abrasive grains (Configuration 5). ).
For example, a surface plate in which fixed abrasive grains containing diamond particles are arranged on a grinding surface and a correction surface of a correction member configured by arranging fixed abrasive grains containing diamond particles are pressed against each other and slid. In this case, if both are diamond particles, the diamond particles on the surface layer are immediately clogged, and the resin bond (the ground surface of the surface plate) cannot be ground. When a grinding fluid containing loose abrasive grains is supplied, both resin bonds can be ground simultaneously.
Examples of the free abrasive grains include alumina, zirconia, silica, silicon carbide and the like. As the free abrasive grains, mixed abrasive grains of alumina, zirconia, and silica are preferable.
In the present invention, the particle size of the loose abrasive grains (particles) is preferably about # 1000 to # 4000, more preferably about # 3000 (for example, # 2900 to # 3100).

In this invention, the said correction process can be performed following the fixed abrasive grain arrangement | positioning process which arrange | positions fixed abrasive grains on the grinding surface of a surface plate (structure 6).
The present invention is excellent in determining the initial conditions of the ground surface of the surface plate. For this reason, for example, each time the diamond sheet is replaced, the initial condition of the flatness of the ground surface of the surface plate can be determined with high accuracy and good reproducibility.
Specifically, according to the present invention, when the surface of the surface plate in which the fixed abrasive is arranged on the grinding surface is corrected by a correction carrier, a surface plate in which the fixed abrasive is arranged on the grinding surface is prepared, Even when initial smoothness is imparted to the fixed abrasive grains (grinding surface) of the surface plate (initial correction is performed), the flatness of the fixed abrasive grains (grinding surface) of the surface plate after correction is obtained. Numerical value (for example, the flatness of the grinding surface when the length from the inner peripheral edge to the outer peripheral edge of the fixed abrasive grains (grinding surfaces) of the upper and lower surface plates in the radial direction of the surface plate is about 540 mm) Can be achieved (initial smoothness can be prepared). As a result, the glass substrate or the like ground using this surface plate can be finished with a flatness of a predetermined value or more each time initial correction is performed.

In this invention, the said correction process can be performed after the grinding process which grinds the main surface of a glass substrate using the surface plate by which the fixed abrasive grain was arrange | positioned by the grinding surface.
The present invention is also excellent in recovering the flatness of the ground surface of the surface plate. Every time a predetermined number of batches are processed, the flatness of the ground surface of the surface plate can be recovered with high accuracy and good reproducibility.
Specifically, according to the present invention, after performing a grinding process of a glass substrate such as a mask blank substrate, even when the surface of the surface plate in which the fixed abrasive grains are arranged on the grinding surface is corrected by the correction carrier, The flatness of the fixed abrasive grains (grind surface) of the surface plate can be reliably recovered to a value greater than the required value.

In the present invention, the correction carrier is provided with an outer gear on the outer periphery of the main body portion, and the outer gear meshes with both gears between the sun gear and the internal gear of the grinding device, whereby the surface plate It is preferable that the correction carrier is revolved while rotating (Configuration 7).
The correction carrier of the present invention can be replaced with a carrier that holds a glass substrate as a substrate to be ground in the grinding apparatus, so that the configuration of the grinding apparatus can be used when correcting the surface of the surface plate. .

In the present invention, the correction carrier is a correction carrier used when the surface of the surface plate is corrected with respect to a grinding apparatus including an upper surface plate and a lower surface plate in which fixed abrasive grains are arranged on the grinding surface,
An outer gear provided on the outer periphery to mesh with both gears between the sun gear and the internal gear of the grinding device, and a main body having two opposing surfaces respectively facing the upper surface plate and the lower surface plate;
A correction member disposed on each of the two opposing surfaces,
The correction member may be arranged along the outer peripheral side of the opposing surface and also arranged on the opposing surface on a straight line connecting the rotation axis of the correction carrier and a specific point on the outer peripheral side (configuration) 10).
According to the modified carrier having such a configuration, the grinding apparatus can be replaced with a carrier that holds a glass substrate that is a substrate to be ground. Available.
Further, according to the correction carrier having such a configuration, the accuracy of the flatness correction of the fixed abrasive grains (grinding surface) of the surface plate can be calculated by a numerical value (specifically, the inner peripheral edge of the fixed abrasive grains (grinding surface)). The height difference from the portion to the outer peripheral end can be improved more than about 20 μm. For example, the accuracy in correcting the flatness of the fixed abrasive grains (grinding surface) of the surface plate can be improved to about 15 μm in height difference from the inner peripheral end portion to the outer peripheral end portion of the fixed abrasive grains (grinding surface).
Furthermore, according to the modified carrier having such a configuration, the fixed abrasive grains (grinding surfaces) of the upper and lower surface plates in the double-side grinding apparatus can be simultaneously flattened.
In the present invention, the correction member is also arranged on a straight line that connects the specific point and the rotation axis to a point on the outer peripheral side opposite to the specific point with the rotation axis interposed therebetween. (Configuration 11). This is the same as described in configuration 2 above.
In the present invention, the correction member may be configured by disposing fixed abrasive grains including diamond particles (Configuration 12). This is the same as that described in configuration 4 above.

In the present invention, it is desirable that the main body (frame) of the correction carrier is formed of a highly rigid material in order to minimize the deformation of the correction carrier during the grinding surface correction process. For example, metal (SUS) is preferable.
In the present invention, the main body of the correction carrier is formed by connecting a ring-shaped (annular) portion (outer peripheral portion) and a ring-shaped portion (outer peripheral portion) in the diameter direction of the ring-shaped portion (outer peripheral portion). It is preferable that the structure has a portion (diameter portion). When the main body of the correction carrier has such a shape, chips and the like are easily removed and the correction carrier is easy to handle, compared to the case where the main body of the correction carrier has a disk shape (no cutout). .

In the present invention, the correction step is such that the outer peripheral end of the correction member in the outer peripheral portion (outer peripheral portion) of the main body portion of the correction carrier is on the outer peripheral side of the outer peripheral end of the fixed abrasive, Overhanging the correction member on the outer peripheral side of the surface plate so that the inner peripheral end is on the inner peripheral side than the outer peripheral end of the fixed abrasive, and
The outer peripheral end of the correction member is on the inner peripheral side of the inner peripheral end of the fixed abrasive, and the inner peripheral end of the correction member is on the outer peripheral side of the inner peripheral end of the fixed abrasive. As described above, it is preferable to overhang the correction member on the inner peripheral side of the surface plate.
According to the said structure, with respect to the outer peripheral edge part and inner peripheral edge part of the fixed abrasive (grinding surface) of a surface plate, the correction member (1 of several correction members in the outer peripheral part (outer peripheral part) of the main-body part of a correction carrier. Or part of the correction member) does not protrude completely. For this reason, regarding the accuracy of the flatness correction of the fixed abrasive grains (grinding surface) of the surface plate, the required numerical value (specifically, the height difference from the inner peripheral edge to the outer peripheral edge of the fixed abrasive grains (grinding surface)) Is about 20 μm).
In the overhang, the correction member (one of the plurality of correction members or a part of the correction member) in the outer peripheral portion (outer peripheral portion) of the main body of the correction carrier is the outer peripheral edge of the fixed abrasive (grind surface) of the surface plate. Or a correction member (one of a plurality of correction members or a part of the correction member) on the outer peripheral portion (outer peripheral portion) of the main body of the correction carrier is fixed abrasive (ground) This occurs when passing near the inner peripheral edge of the surface.
In the present invention, the overhang is an outer periphery of the main body portion of the correction carrier with respect to an outer peripheral end portion of the fixed abrasive (grind surface) of the surface plate in an arbitrary radial direction (one or more radial directions) on the surface plate. The correction member (one of the plurality of correction members or a part of the correction member) in the portion (outer peripheral portion) is shifted (protruded toward the outer peripheral side of the surface plate) toward the distance from the center of the surface plate in the radial direction of the surface plate. (But do not protrude completely) and the correction member (there is a plurality of correction members in the outer peripheral portion (outer peripheral portion) of the main body portion of the correction carrier with respect to the inner peripheral end portion of the fixed abrasive (grinding surface) of the surface plate One of the correction members, or a part of the correction member, shifts (protrudes) toward the center of the surface plate in the radial direction of the surface plate (to the inner peripheral side of the surface plate) (but does not protrude completely) ).
As the correction member in the outer peripheral portion (outer peripheral portion) of the main body of the correction carrier moves relative to the surface plate, the radial position on the surface plate where the correction member overhangs to the maximum also changes. In all the positional relationships that the correction member can take relative to the surface plate, the outer peripheral portion (outer periphery) of the main body of the correction carrier with respect to the outer peripheral end and inner peripheral end of the fixed abrasive (grind surface) of the surface plate It is necessary that the correction member (one of the plurality of correction members or a part of the correction member) does not protrude completely.

The present invention can be applied to grinding of substrates such as quartz glass, alkali-free glass, borosilicate glass, aluminosilicate glass, and soda lime glass. In addition, the present invention can be applied to grinding of a substrate such as crystallized glass on which β-quartz solid solution is precipitated, for example, if it is amorphous glass, SiO ₂ —TiO ₂ glass, or crystallized glass.
The substrate manufacturing method in the present invention can be applied to a mask blank glass substrate, a glass substrate for a display device using liquid crystal or organic EL, a glass substrate for a magnetic disk, and the like.
In the present invention, the case where the substrate is used a glass substrate for a mask blank is preferably a low thermal expansion glass such as synthetic quartz glass or SiO ₂ -TiO ₂ type glass. This is because the present invention is particularly suitable for grinding a substrate made of low thermal expansion glass such as synthetic quartz glass or SiO ₂ —TiO ₂ glass.

The mask blank manufacturing method of the present invention is characterized in that a thin film for forming a transfer pattern is formed on the main surface of the mask blank substrate manufactured by the substrate manufacturing method of the present invention (Configuration 8). .
With the above configuration, it is possible to manufacture a mask blank having a substrate with a high flatness of a predetermined value or less.

The transfer mask manufacturing method of the present invention is characterized by patterning the thin film in the mask blank manufactured by the mask blank manufacturing method of the present invention to form a transfer pattern (Configuration 9).
With the above configuration, it is possible to manufacture a transfer mask having a substrate with high flatness of a predetermined value or less.

  Next, an embodiment of a substrate manufacturing method according to the present invention will be described in detail with reference to the accompanying drawings. In the following, the case of grinding a glass substrate for a mask blank will be described in particular, but the present invention can also be applied to the case of grinding a glass substrate for a display device using a liquid crystal or an organic EL and a glass substrate for a magnetic disk. In the figure, elements not directly related to the present invention are not shown. Similar elements are denoted by the same reference numerals.

  FIG. 1 is a schematic plan view for explaining a configuration of a general planetary gear type grinding / polishing apparatus, and is a view for explaining a planetary motion of a carrier. A ground / polished substrate (glass substrate) 100 is held on a lower surface plate 10 by a carrier 50 having an outer gear on its outer periphery. (Internal gear) 40 is engaged with both gears 30 and 40 respectively. For example, by rotating the sun gear 30 and the internal gear 40 in the directions of the arrows, the carriers 50 revolve while rotating as planetary gears in the directions of the arrows.

FIG. 2 is a schematic cross-sectional view for explaining the configuration of a general planetary gear type grinding / polishing apparatus. The upper surface plate 20 is movable in the vertical direction with respect to the lower surface plate 10. 2 illustrates a state in which both the main surfaces of the grinding / polishing substrate (glass substrate) 100 are ground and polished with the grinding / polishing substrate (glass substrate) 100 interposed therebetween. As shown in FIG. 2, the upper surface plate 20 and the lower surface plate 10 are each provided with fixed abrasive grains 11 and 21 on the grinding surface during grinding (or latticed grooves on the upper and lower surface plates). In this case, polishing pads (polishers) 11 and 21 are provided on the polishing surface. For example, the main surface of the glass substrate 100 is ground and polished by rotating the upper and lower surface plates 10 and 20.
The two-way method in which the upper and lower surface plates 10 and 20 are not driven and the sun gear 30 and the internal gear 40 are driven, and the three-way method in which the internal gear 40 is fixed and the upper and lower surface plates 10 and 20 and the sun gear 30 are driven ( Internal fixed type), three-way system (upper surface plate fixed type) for fixing the upper surface plate 20 and driving the lower surface plate 10, sun gear 30, and internal gear 40, upper and lower surface plates 10, 20, sun gear 30, internal A four-way system that drives all four axes of the gear 40 is applicable.
The planetary gear type grinding / polishing apparatus can be applied to a double-sided grinding / polishing apparatus and a single-sided grinding / polishing apparatus.

The object of the embodiment of the present invention is to perform surface correction of the upper and lower surface plates 10 and 20 in which the fixed abrasive grains 11 and 21 are provided on the grinding surface (see FIGS. 3 and 4).
In order to correct the surface of the surface plate, the flatness of the fixed abrasive grains (grind surface) of the surface plate is corrected using a correction member.

FIG. 3 is a diagram showing an example of a correction carrier and a correction member used in the embodiment of the present invention. 4 is a partial cross-sectional view of the surface plate, and is a cross-sectional view taken along the line AA of FIG.
The correction carrier 51 shown in FIGS. 3 and 4 has a configuration that can replace the carrier 50 shown in FIG. That is, the correction carrier 51 is provided with an outer gear on the outer periphery of the outer peripheral portion 52 constituting the main body portion, and the outer gear is connected to both the gears between the sun gear 30 and the internal gear 40 of the grinding device. By meshing, the correction carrier 51 can be revolved while rotating on the surface plates 10 and 20.

In the present invention, for example, as shown in FIG. 1, each carrier 50 is used as a planetary gear when grinding / polishing the ground / polishing substrate (glass substrate) 100, and each carrier 50 is replaced when the surface of the surface plate is corrected. The correction carrier 51 shown in FIGS. 3 and 4 can be installed as a planetary gear.
When the surface of the surface plate is corrected using the correction carrier, all the carriers 50 shown in FIG. 1 are removed, and the correction carrier 51 shown in FIG. At least one correction carrier 51 may be arranged on the surface plate, but a plurality of correction carriers 51 may be arranged when it is desired to shorten the correction time.

As shown in FIGS. 3 and 4, in the radial direction of the surface plates 10 and 20, fixed abrasive grains (specifically 5 to 100 mm) on the inner peripheral side of the outer peripheral end portions 10 a and 20 a of the surface plate (specifically 5 to 100 mm) Grinding surface) The outer peripheral end portions 11a, 21a of the 11, 21 are located, and are fixed to the outer peripheral side by an appropriate amount (specifically, 5-100 mm) from the inner peripheral end portions 10b, 20b of the surface plates 10, 20 It arrange | positions so that the inner peripheral edge parts 11b and 21b of the grain (grind surface) 11 and 21 may be located. By adopting such an arrangement, the substrate manufacturing method of the present invention can be applied even when a polishing apparatus or a grinding apparatus designed on the assumption that the substrate is not overhanged during polishing or grinding of the substrate is used.
In this case, the outer peripheral end portions 11a and 21a and the inner peripheral end portions 11b and 21b of the fixed abrasive grains (grinding surfaces) 11 and 21 on the surface plates 10 and 20 are respectively substantially equal distances (radius) from the center O of the surface plate. ) Is placed on the circumference.
As the fixed abrasive grains (grinding surfaces) 11 and 21 on the surface plates 10 and 20, a diamond sheet (diamond particle size # 3000) is used.

As shown in FIG. 3, a plurality of circular correction members 53 of the same size are attached along the circumference of a ring (annular) -shaped portion (referred to as an outer peripheral portion) 52 of the correction carrier 51. The plurality of correction members 53 are arranged on the ring-shaped outer peripheral portion 52 of the correction carrier 51 at substantially equal distances from the center O ′ of the correction carrier 51 at substantially equal intervals.
A central portion of the correction carrier 51 has a portion (referred to as a diameter portion) 54 formed to be connected to the ring-shaped outer peripheral portion 52 in the diameter direction of the ring-shaped outer peripheral portion 52. The correction member 55 is formed in a portion excluding the vicinity of the center of the diameter portion 54 in the correction carrier 51. The correction member 55 can also be formed entirely on the diameter portion 54 of the correction carrier 51.
The main body of the correction carrier 51 includes an outer peripheral part 52 and a diameter part 54. In the present invention, correction members 53 and 55 are attached to the upper and lower surfaces (two surfaces opposite to the main body portion) of the outer peripheral portion 52 and the diameter portion 54 constituting the main body portion (metal frame) of the correction carrier, respectively. Is.
As shown in FIG. 3, the correction member 53 is disposed along the circumference of the ring-shaped outer peripheral portion 52 of the correction carrier 51, and the entire ring-shaped outer peripheral portion 52 is not covered with the correction member 53. . This is because if the entire ring-shaped outer peripheral portion 52 is covered with the correction member 53, the frictional force becomes too large when it comes into contact with the surface plate, making it difficult to rotate the correction carrier relative to the surface plate. There is a risk that an excessive shearing force is applied to the fixed abrasive and the fixed abrasive falls off the sheet or the sheet itself peels off from the surface plate.
Further, the size, spacing, arrangement (attachment position), etc., of the correction members 53 and 55 are adjusted in order to achieve the purpose of the correction itself, that is, to achieve the purpose of improving the smoothness of the ground surface of the surface plate by relative movement. There is a need.

When the total area of the correction members 53 is B, the total area of the correction members 55 is preferably 0.4 to 0.8B, and more preferably 0.5 to 0.7B.
When the area of the circle having the radius r shown in FIG. 3 is C, the total area of the correction members 55 is preferably 0.1 to 0.6C, and more preferably 0.3 to 0.5C.

As shown in FIGS. 3 and 4, the arrangement of the correction member 53 in the ring-shaped outer peripheral portion 52 of the correction carrier 51 is in the radial direction of the surface plate passing through the center O of the surface plate and the center O ′ of the correction carrier 51.
The outer peripheral end 53a of the correction member 53 is on the outer peripheral side of the outer peripheral ends 11a and 21a of the fixed abrasive grains (grinding surfaces) 11 and 21, and the inner peripheral end portion 53b of the correction member 53 is the fixed abrasive grains (grinding surface). ) 11 and 21 are located on the inner peripheral side of the outer peripheral end portions 11a and 21a, and
The outer peripheral end 53a of the correction member 53 is on the inner peripheral side with respect to the inner peripheral ends 11b and 21b of the fixed abrasive grains (grinding surfaces) 11 and 21, and the inner peripheral end 53b of the correction member 53 (of the correction carrier 51). The arrangement is such that the end near the center O ′ is closer to the outer peripheral side than the inner peripheral end portions 11b and 21b of the fixed abrasive grains (grinding surfaces) 11 and 21.

As the correction members 53 and 55, a diamond sheet (diamond particle size # 3000) is used.
The flatness of the correction surfaces of the correction members 53 and 55 (measured using a stylus type surface straightness measuring device) is preferably 20 μm or less, and more preferably 10 μm or less.

When the area of the correction member 53 is S, the maximum overhang amount is preferably 0.05 to 0.5S (the overhang amount is less than or equal to half of the total area S of the correction member).
Similarly, when the length h of the correction carrier in the correction member in the radial direction is set to h, the maximum value of the overhang amount is 0.5 h or less (the overhang amount is less than half of the length h of the correction carrier in the radial direction of the correction member) ) Is preferred (see FIG. 3).
The correction member is compressed by the pressure applied by the upper and lower surface plates. When the correction member overhangs from the ends of the fixed abrasive grains (grinding surfaces) 11 and 21 of the upper and lower surface plates (overhangs and jumps out), the overhanging portion of the correction member (the protruding portion and the portion protruding outward) ) Will release the pressure and increase the thickness. The overhanging portion (the protruding portion and the protruding portion) of the correction member whose thickness is increased by releasing the pressure enters toward the fixed abrasive grains (grinding surfaces) 11 and 21 of the upper and lower surface plates. When going, the fixed abrasive grains (grinding surface) of this part are shaved more than necessary, which hinders improvement in the accuracy of flatness correction of the fixed abrasive grains (grinding surface) of the surface plate.
From the viewpoint of reducing the influence of pressure release applied to the correction member by the upper and lower surface plates, the maximum value of the overhang amount is preferably 0.1 to 0.4 S, and preferably 0.2 to 0.00. 3S is more preferable.

When the radius of the correction carrier 51 is R, the radial width w of the correction carrier in the outer peripheral portion 52 of the correction carrier is preferably about 0.1 to 0.3R, and more preferably around 0.2R (see FIG. 3). ).
When the radial width of the correction carrier in the outer peripheral portion 52 of the correction carrier is w, the radial width h of the correction carrier in the correction member 53 is preferably about 0.1 to 0.7 w, and is about 0.4 w ( For example, 0.35 to 0.45 w) is more preferable (see FIG. 3).

As shown in FIG. 4, when correcting the smoothness of the grinding surfaces 11, 21 provided with the fixed abrasive grains of the upper and lower surface plates 10, 20, the correction carrier 51 is ground on the grinding / polishing substrate (glass substrate) 100. In the same manner as in the case, it is sandwiched between the upper and lower surface plates 10 and 20 and is slid while being pressed against each other. As a result, the grinding surfaces 11 and 21 provided with fixed abrasive grains are shaved, and their heights become uniform. In other words, the ground surface that needs to be initially flattened in the preparation process of the surface plate and the flatness of the ground surface that has decreased in the grinding process have been corrected. The flatness of the ground surface can be imparted to and recovered from the substrate 100).
At this time, it is preferable to correct using a slurry containing free abrasive grains (for example, a particle size of 4 to 15 μm). As the free abrasive grains, mixed abrasive grains of alumina, zirconia, and silica are preferable.
In the correction step, the machining allowance of the grinding surfaces 11 and 21 provided with the fixed abrasive grains of the upper and lower surface plates 10 and 20 is preferably 5 to 50 μm.

The thickness obtained by adding the outer peripheral portion 52 or the diameter portion 54 constituting the main body portion of the correction carrier 51 and the correction member 53 or 55 should be thicker than the ground / polishing substrate (glass substrate) 100 shown in FIG. Is preferred.
The reason for providing such a thickness is to increase the correction capability of the correction carrier 51. In the case of a double-side polishing machine such as the upper and lower surface plates 10 and 20, the higher the thickness of the object to be processed that is sandwiched between them, the higher the bending strength, so that the correction carrier is less likely to be deformed, and high-precision correction processing. Easy to do. The same applies when the upper and lower surface plates 10 and 20 are corrected by the correction carrier 51, and the thickness obtained by adding the outer peripheral portion 52 or the diameter portion 54 constituting the main body of the correction carrier 51 and the correction member 53 or 55 is large. The correction ability improves.
The correction surfaces of the correction members 53 and 55 of the correction carrier 51 having such a thickness and the grinding surfaces 11 and 21 of the upper and lower surface plates 10 and 20 are pressed against each other while supplying loose abrasive grains. Thus, the flatness of the grinding surfaces 11 and 21 of the upper and lower surface plates 10 and 20 can be improved.

In the mask blank substrate manufacturing method of the present invention, the grinding conditions are, for example, polishing liquid (alumina, zirconia, silica mixed abrasive grains (average particle size 4 to 15 μm) + water), processing load 50 to 200 g / cm. ² , Polishing time 2 to 60 minutes, Corrected carrier rotation speed 0.5 to 10 rpm, Corrected carrier revolution speed 0.5 to 10 rpm, Polishing surface plate speed 2 to 20 rpm, etc. are preferable.

[Example]
(Example 1, Comparative Example 1)
Four diamond sheets (# 3000) were attached as fixed abrasive grains (grinding surfaces) 11 and 21 to the upper and lower surface plates of a double-sided grinding (lapping) device (see FIG. 7).
The profile of the grinding surface of the upper and lower surface plates immediately after the diamond sheet was pasted (before correction) was measured. The results are shown in FIG. 9 and FIG.
Initial correction was performed with the correction carrier shown in FIGS. 3 and 4 (the correction member 53 was a diamond sheet (# 3000)) (Example 1). The result of measuring the profile of the ground surface of the upper and lower surface plate after correction is shown in FIGS.
Initial correction was performed with the correction carrier shown in FIGS. 5 and 6 (the correction member 53 was a diamond sheet (# 3000)) (Comparative Example 1). The results of measuring the profile of the ground surface of the upper and lower surface plate after correction are shown in FIGS. 5 and 6 are the same as FIGS. 3 and 4 except that the diameter portion 54 and the correction member 55 in the correction carrier 51 are not included in FIGS. No. will be omitted.
Initial correction was performed with the correction carrier shown in FIG. 8 (the correction member 53 was a diamond sheet (# 3000)) (Reference Example 1).
The initial correction was performed under the following conditions.
Grinding fluid: Alumina, zirconia, silica mixed abrasive (average particle size 10 μm) + water processing load: 100 g / cm ²
Grinding time: 10 minutes Corrected carrier rotation speed: 2 rpm
Corrected carrier revolution speed: 5 rpm
Plate rotation speed: 12rpm
Surface plate radius: about 1800mm
Double-side grinding is a four-way method, and the rotation directions of the upper and lower surface plates are reversed, and the rotation directions of the sun gear and the internal gear are reversed.
Further, as shown in FIG. 7, since the sun gear 30 is at the center of the surface plate, the profile cannot be measured with a measuring machine in the diameter direction of the surface plate. For this reason, the profile (entire surface) was measured with a measuring machine at the measurement position shown in FIG. Based on the measurement data, a profile (left) is obtained from the measurement data of the left fixed abrasive portion shown in FIG. 7, and a profile (right) is obtained from the measurement data of the right fixed abrasive portion shown in FIG. . The flatness of the fixed abrasive calculated from this profile (left) or profile (right) is calculated to be equal to or greater than the flatness of the fixed abrasive in the radial direction. For this reason, the flatness of the fixed abrasive calculated from the profile (left) or the profile (right) can be replaced with the flatness of the fixed abrasive in the radial direction. In this way, the measurement data shown in FIGS. 9, 10, 11, 12, 13, and 14 were obtained.
In Example 1, Comparative Example 1 and Reference Example 1, in the radial direction of the surface plate, the outer peripheral ends of the fixed abrasive grains (grinding surfaces) 11 and 21 on the inner peripheral side 100 mm from the outer peripheral end portions 10a and 20a of the surface plate Arrangement is such that the portions 11a and 21a are located, and the inner peripheral ends 11b and 21b of the fixed abrasive grains (grinding surfaces) 11 and 21 are located 100 mm outer peripheral side than the inner peripheral ends 10b and 20b of the surface plate. It is.

As shown in FIG. 9 and FIG. 10, when the diamond sheet is divided into several pieces on the surface plate, the step of the diamond sheet needs to be corrected (initial correction before polishing).
In Example 1, the flatness correction of the grinding surface provided with the fixed abrasive grains containing diamond particles is performed as shown in FIGS. 9 and 10 [the surface plate surface (grind surface) of the upper surface plate is concave (the surface plate surface is horizontal). From the direction, the surface is convex, and the flatness is about 60 μm. The surface of the lower surface plate (grind surface) is convex (the surface is convex upward when viewed from the horizontal direction), and the flatness is about 55 μm]. 11 and 12 [the surface plate surface (grinding surface) of the upper surface plate is concave (the surface is convex upward when viewed from the horizontal direction) and the flatness is about 20 μm, the surface plate surface of the lower surface plate (grind surface) ) Was convex (convex upward when the surface plate surface was seen from the horizontal direction) and the flatness was about 15 μm]. Further, the accuracy of flatness correction can be improved more than the required value (the flatness of the surface plate is about 800 mm and the flatness of the upper and lower surfaceplates is about 20 μm, respectively) (the flatness of the surface plate is about 800 mm and the flatness of the lower surface plate is improved. It was improved to 15 μm).
In Comparative Example 1, the flatness correction of the grinding surface on which the fixed abrasive grains containing diamond particles are arranged is changed from the state shown in FIG. 9 and FIG. 10 to the state shown in FIG. 13 and FIG. Surface) is concave (convex upward when the surface plate surface is seen from the horizontal direction) and flatness is about 20 μm, and the surface plate surface (grind surface) of the lower surface plate is convex (convex shape when the surface plate surface is viewed from the horizontal direction). ), The flatness could be corrected to about 20 μm. In addition, the accuracy of flatness correction can be obtained as required (the radius of the surface plate is about 800 mm and the flatness of the upper and lower surface plates is about 20 μm, respectively). However, as seen in the radial direction of the surface plate (lower surface plate), it is understood that the shape is corrected to a convex shape (very small) from the outer peripheral edge side and the inner peripheral edge side toward the central side.
In Comparative Example 1, when the correction member is arranged only on the outer periphery of the correction carrier and the flatness correction of the fixed abrasive grains (the surface plate surface) on the surface plate is advanced, as shown in FIG. 13 and FIG. A phenomenon occurs in which the distance between the ground surfaces of the surface plate and the lower surface plate is the same (the surface plate surface (grind surface) has the same shape of the crest). If the distance between the ground surfaces of the upper surface plate and the lower surface plate is the same, the correction rate on the surface plate becomes the same in the surface, and a phenomenon that the tendency of the convex shape cannot be corrected occurs.

In Reference Example 1, as shown in FIG. 8, when the correction member 53 overhangs to the maximum on the outer peripheral side of the surface plate 10 with respect to the outer peripheral end portion 11 a of the fixed abrasive grains (grinding surface) 11 of the surface plate 10. The end 53 b on the inner peripheral side of the correction member 53 is located on the outer peripheral side of the outer peripheral end 11 a of the fixed abrasive (grinding surface) 11 of the surface plate 10, that is, the fixed abrasive of the surface plate 10. The entire correction member 53 protrudes from the outer peripheral end portion 11 a of the (grinding surface) 11. Similarly, when the correction member 53 overhangs at the maximum on the inner peripheral side of the surface plate 10 with respect to the inner peripheral end portion 11 b of the fixed abrasive (grinding surface) 11 of the surface plate 10, the correction member 53. The end 53b on the inner peripheral side of the surface plate 10 is located on the inner peripheral side of the inner peripheral end portion 11b of the fixed abrasive (grinding surface) 11 of the surface plate 10, that is, the fixed abrasive (grinding surface of the surface plate 10). ) The entire correction member 53 protrudes from the inner peripheral end portion 11 b of 11. For this reason, in Comparative Example 1, the flatness correction of the grinding surface provided with the fixed abrasive grains containing diamond particles is inferior to the required numerical value (for example, the surface plate has a radius of about 800 mm and the surface plate has a flatness of about 20 μm). It can only be corrected to a numerical value (for example, a surface plate radius of about 800 mm and a surface plate surface flatness of about 35 μm).
In Reference Example 1, the problem that the fixed abrasive on the surface plate shown in Comparative Example 1 is corrected to a convex shape (very small) is the above-mentioned correction to the fixed abrasive (grind surface) of the surface plate. It can be seen that when the overhang amount of the member is excessively large, it does not become obvious.

(Grinding of mask blank substrate)
A glass substrate obtained by chamfering an end surface of a synthetic quartz glass substrate (about 6 inches × about 6 inches) and performing at least a first grinding process by a double-sided lapping apparatus is used for the surface plate in Example 1 and Comparative Example 1 described above. It was set in a double-sided grinding machine that corrected the flatness of the grinding surface, and the grinding process was performed under the following grinding conditions. The processing load and grinding time were adjusted as appropriate.
Grinding liquid: grinding agent + water After the grinding process, the glass substrate was immersed in a cleaning tank (ultrasonic application) to remove the abrasive grains adhering to the glass substrate, and then washed.
The glass substrate or the like ground using the surface plate to which the diamond sheet of Example 1 is attached can be finished to have a flatness of 1.0 μm or less in absolute value on both the front and back surfaces. For this reason, the present invention is not only an alternative to the grinding process by the conventional cast iron surface plate, but also can omit or simplify the rough polishing process (first polishing) described later, which is very useful (polishing process). Part of Therefore, a configuration in which “grinding” is replaced with “polishing” in the present invention described above (in the present specification) is included in the present invention. For example, a configuration in which “grinding” is replaced with “polishing” in the claims, the detailed description of the invention, the embodiment of the invention, the examples, and the like is included in the present invention.
It was difficult to obtain a glass substrate or the like ground using the surface plate of Comparative Example 1 with a flatness of 1.3 μm or less in absolute value on both the front and back surfaces.

(Example 2)
In order to correct the flatness of the ground surfaces of the surface plates 10 and 20 that were lowered in the grinding process after the grinding process of grinding the main surface of several tens of batches of glass substrates, the correction was performed in the same manner as in Example 1. .
The same tendency as the result of the initial correction in Example 1 was observed.

(Example 3)
(Manufacture of mask blank substrate)
(1) Precision polishing process A glass substrate ground using each surface plate of Example 1 and Comparative Example 1 was prepared and set in a double-side polishing apparatus, and a precision polishing process was performed under the following polishing conditions. The processing load and polishing time were adjusted appropriately. Therefore, the rough polishing process (polishing process performed with a cerium oxide polishing liquid having an average particle diameter of 2 to 3 μm) performed before the precision polishing process has been omitted.
Polishing liquid: cerium oxide (average particle size 1 μm) + water polishing pad: soft polisher (suede type)
After completion of the precision polishing step, the glass substrate was immersed in a cleaning tank (ultrasonic application) in order to remove the abrasive grains adhering to the glass substrate and cleaned.

(2) Ultra-precision polishing process The ultra-precise polishing process was carried out under the following polishing conditions after being set in the above-described double-side polishing apparatus. The processing load and polishing time were adjusted as appropriate.
Polishing liquid: colloidal silica (average particle size 100 nm) + water polishing pad: super soft polisher (suede type)
After the completion of the ultraprecision polishing process, the glass substrate was immersed in a cleaning tank (ultrasonic application) in order to remove the abrasive grains adhering to the glass substrate, and cleaning was performed.

(3) Flatness measurement process About the board | substrate (each 12 sheets) of Example 1 after the ultraprecision grinding | polishing process was performed, and flatness (TIR) in the 142-mm square area | region of a main surface. It measured with the measuring device (UltraFlat200M by Corning Tropel). As a result, for the substrate of Example 1, the shape of the main surface was a convex shape with a flatness in the range of 0 μm or more and within +0.2 μm. On the other hand, as for the substrate of Comparative Example 1, as for the shape of the main surface, the convex shape having a flatness (TIR) larger than +0.2 μm occupies the majority (average 9 sheets), resulting in poor yield. It became.

  In the substrate manufacturing method of the present invention, for example, a first grinding step (Lap1), a second grinding step (Lap2), a rough polishing step (first polishing), an edge polishing step, a precision polishing step (second polishing), In the steps of the ultraprecision polishing step 1 (third polishing) and the ultraprecision polishing step 2 (fourth polishing), for example, instead of the first grinding step (Lap1) and the rough polishing step (first polishing), It becomes possible to perform a step of processing the substrate after the second grinding step by using a double-sided grinding apparatus having an upper and lower surface plate whose surface plate (grinding surface) is initially corrected using a correction carrier. In this case, quality such as final substrate flatness (TIR) can be maintained. In this case, the machining allowance in the first grinding step (Lap1) or the like can be reduced by about 30%.

(Evaluation after producing mask blank and photomask)
On one main surface of each glass substrate obtained in Example 1 above, a light-shielding layer (MoSiN film) containing molybdenum, silicon and nitrogen, and an antireflection layer (MoSiN film) containing molybdenum, silicon and nitrogen A light shielding film (total film thickness: 60 nm) having a structure in which two layers are stacked was formed by sputtering, respectively, to manufacture a binary mask blank.
Next, a resist film was applied and formed on the light shielding film of each manufactured mask blank by spin coating. Subsequently, a desired fine pattern was formed on the resist film by exposure and development. Furthermore, by using the resist film as a mask, the light shielding film was dry-etched to form a transfer pattern on the light shielding film, thereby producing a binary transfer mask.

  Using each transfer mask produced from the substrate of Example 1, it was set on the mask stage of the exposure apparatus, and exposure transfer was performed by irradiating ArF excimer laser light onto the transfer object (resist film or the like on the wafer). As a result, it was confirmed that the desired pattern was normally transferred to the transfer object.

(Evaluation after manufacturing reflective mask blank and reflective mask)
A multilayer reflective film in which molybdenum (Mo layer) and silicon (Si layer) were alternately laminated was formed on one main surface of each glass substrate obtained in Example 1 above. Specifically, a Si layer of 4.2 nm and a Mo layer of 2.8 nm are formed from the glass substrate side, respectively, and this is repeated for 40 cycles, and finally a Si layer of 4.0 nm is formed to form a multilayer reflective film. did. Next, a protective film made of a material containing ruthenium was formed to 2.5 nm on the multilayer reflective film. Finally, an absorber film mainly composed of tantalum was formed on the protective film to manufacture a reflective mask blank.

  Next, a resist film was applied and formed on the light shielding film of each manufactured reflective mask blank by spin coating. Subsequently, a desired fine pattern was formed on the resist film by exposure and development. Furthermore, by performing dry etching on the absorber film using the resist film as a mask, a transfer pattern was formed on the absorber film, and a reflective mask was manufactured.

  Using each reflection type mask produced from the substrate of Example 1, it is set on the mask stage of the exposure apparatus, and exposure transfer is performed by irradiating the transfer object (resist film etc. on the wafer) with EUV (Extreme Ultra Violet) light. went. As a result, it was confirmed that the desired pattern was normally transferred to the transfer object.

10 Lower surface plate 20 Upper surface plate 30 Sun gear (sun gear)
40 Internal gear (internal gear)
50 Carrier 51 Correction carrier 52 Outer peripheral portion 53 Correction member 54 Diameter portion 55 Correction member 100 Grinding / polishing substrate (glass substrate)

Claims (12)

A method for manufacturing a substrate, comprising a grinding step in which two main surfaces of a glass substrate are ground on both sides using a grinding apparatus having an upper surface plate and a lower surface plate in which fixed abrasive grains are arranged on a grinding surface,
A correction step of revolving a correction carrier having a correction member while rotating on the surface plate, and correcting the surface of the surface plate by sliding the correction member of the correction carrier and the ground surface of the surface plate while pressing each other. Have
The modified carrier is composed of a main body portion having two opposed surfaces respectively facing the upper surface plate and lower surface plate, respectively arranged modifying member to said two opposite faces,
The main body portion is composed of a ring-shaped outer peripheral portion and a diameter portion formed to be connected to the outer peripheral portion in the diameter direction of the outer peripheral portion,
The method for manufacturing a substrate, wherein the correction member is disposed along a circumference of the opposing surface of the outer peripheral portion , and is also disposed in a portion excluding the vicinity of the center of the opposing surface of the diameter portion . The thickness of the outer peripheral portion and the thickness of each of the correction members disposed on the two opposing surfaces of the outer peripheral portion are thicker than the thickness of the glass substrate, and the thickness of the diameter portion and the diameter The method of manufacturing a substrate according to claim 1, wherein a thickness of each of the correction members disposed on two opposing surfaces of the portion is greater than a thickness of the glass substrate.   The substrate manufacturing method according to claim 1, wherein the surface plate is provided with fixed abrasive grains including diamond particles on a grinding surface.   The method for manufacturing a substrate according to claim 1, wherein the correction member is configured by disposing fixed abrasive grains including diamond particles. 5. The correction step is performed by sliding the correction member and the ground surface of the surface plate while pressing each other while supplying a grinding liquid containing loose abrasive grains. 6. The manufacturing method of the board | substrate in any one.   6. The method for manufacturing a substrate according to claim 1, wherein the correcting step is performed subsequent to a fixed abrasive grain arranging step of arranging fixed abrasive grains on a ground surface of a surface plate. The correction carrier is provided with an outer gear on the outer periphery of the outer peripheral portion, and the outer gear meshes with both gears between the sun gear and the internal gear of the grinding device, thereby The substrate manufacturing method according to claim 1, wherein the correction carrier revolves while rotating.   A method for manufacturing a mask blank, comprising forming a thin film for forming a transfer pattern on a main surface of a substrate manufactured by the method for manufacturing a substrate according to claim 1.   A method for producing a transfer mask, wherein the thin film in the mask blank produced by the method for producing a mask blank according to claim 8 is patterned to form a transfer pattern. For a grinding apparatus having an upper surface plate and a lower surface plate in which fixed abrasive grains are arranged on a grinding surface, a correction carrier used when correcting the surface of the surface plate,
Consists of a body having two opposing surfaces facing each on said surface plate and lower surface plate, respectively arranged modifying member to said two opposite faces,
The main body portion is connected to the outer peripheral portion in a diameter direction of the outer peripheral portion and a ring-shaped outer peripheral portion provided with outer gears that mesh with both gears between the sun gear and the internal gear of the grinding device on the outer periphery. With a diameter part formed by
The correction carrier is disposed along the circumference of the opposing surface of the outer peripheral portion , and is also disposed in a portion excluding the vicinity of the center of the opposing surface of the diameter portion . The thickness of the outer peripheral portion and the thickness of each of the correction members disposed on the two opposing surfaces of the outer peripheral portion are thicker than the thickness of the glass substrate, and the thickness of the diameter portion and the diameter 11. The correction according to claim 10, wherein a thickness obtained by adding each thickness of the correction member disposed on each of two opposing surfaces of the section is thicker than a thickness of a glass substrate to be ground by the grinding apparatus. Career.   The correction carrier according to claim 10 or 11, wherein the correction member is configured by disposing fixed abrasive grains including diamond particles.

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