JP2013225537A - Method for manufacturing sapphire substrate and sapphire substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a sapphire substrate capable of adjusting the amount of warpage by warping a substrate to a predetermined surface in the substrate having a large diameter of 4 inches or more, and also to provide the sapphire substrate.SOLUTION: A method for manufacturing a sapphire substrate in which a substrate 10 obtained by slicing a sapphire ingot and having warpage is subjected to processing including a plurality of steps to manufacture a sapphire substrate includes: a grinding step of grinding both surfaces of the substrate 10; a wet blasting step of performing wet blasting process on one or both of surfaces of the substrate 10 after the grinding step: a sticking step of sticking the substrate 10 to a substrate holding member 300 to hold the substrate 10 after the wet blasting step; a lapping step of performing lapping process on a recessed surface of the substrate 10 after the sticking step; and a grinding step of performing CMP grinding on the lapping-processed surface of the substrate 10 after the lapping step.

Description

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

  Nitride III-V compound semiconductors have been put into practical use as light-emitting devices such as LEDs (Light Emitting Diodes) and electronic devices that make use of features excellent in heat resistance and environmental resistance. This group III-V nitride semiconductor is often grown on a single crystal sapphire substrate. In order to promote the growth normally, the sapphire substrate has a mirror-polished semiconductor growth surface, and the substrate thickness is uneven. Those with a small number and those warped opposite to the semiconductor growth surface (that is, the semiconductor growth surface is concave) are preferably used.

  For the manufacture of sapphire substrates, a cutting process for cutting a substrate from a sapphire ingot, a surface attaching process for attaching the surface of the substrate to a ceramic block using wax, and a back surface for lapping the back surface of the substrate supported by the ceramic block A single-sided lapping step, a heat treatment step for reducing processing distortion caused by lapping after removing the ceramic block and the substrate, a backside attaching step for attaching the backside of the substrate to the ceramic block using wax, And a main surface mechanochemical polishing step in which the surface is subjected to CMP (Chemical Mechanical Polishing) (see Patent Document 1).

  In addition, instead of the front surface bonding process and the back surface single-sided lapping process, a double-sided lapping process for lapping both surfaces of the sapphire substrate or a lapping process before the main surface mechanochemical polishing process is performed and rough polishing is performed in advance. This process is also known as the prior art (see FIG. 8).

  The double-sided lapping machine used in double-sided lapping has, for example, a lapping surface plate to which loose abrasive grains having a particle size of several tens to a hundred μm are supplied, and presses the substrate against this lapping surface plate. It is an apparatus that rotates the lapping plate while scraping both sides of the substrate with the supplied free abrasive grains. Since the particle size of the loose abrasive is larger than the loose abrasive for CMP polishing described later, it is used for rough polishing of the substrate.

  A CMP apparatus used in CMP polishing includes a rotatable polishing table, a polishing pad placed thereon, a polishing head that presses the polishing surface of the substrate against the polishing surface of the polishing pad, and the polishing pad and the substrate. A cleaning liquid supply nozzle that injects a cleaning liquid for cleaning, a free abrasive grain supply nozzle that supplies free abrasive grains, and a motor for rotating the polishing table.

  In the main surface mechanochemical polishing step, for example, alkaline colloidal silica having a particle size of several nm is used as the free abrasive grains. This is smaller than the particle size of the loose abrasive used in lapping.

  With such a CMP apparatus, free abrasive grains are dropped on the polishing pad from the free abrasive supply nozzle, the surface to be polished of the substrate is pressed against the polishing surface of the polishing pad by the polishing head, and the polishing table and the polishing head are rotated. Thus, the free abrasive grains of the colloidal silica which are alkaline and the substrate are chemically reacted and polished chemically and mechanically. Therefore, more accurate polishing than lapping is performed.

JP 2006-347776 A

  Recently, due to the increasing demand for cost reduction and performance improvement of semiconductor elements such as LED elements, it is necessary to shorten and reduce the process and to reduce the board cost and improve the performance by improving the performance of the sapphire substrate. Yes.

  In the conventional method for manufacturing a sapphire substrate disclosed in Patent Document 1, a double-sided lapping apparatus is used. Since the double-sided lapping machine has slight warping and thickness unevenness on the lapping surface plate, for example, processing a substrate with a large diameter and thin thickness of 4 inches or more will affect the warp and thickness unevenness and process with high accuracy. It was difficult to do. Therefore, it is difficult to produce a substrate having a desired amount of warpage on a desired surface of a substrate having a large diameter of 4 inches or more.

  Also, if a substrate of 4 inches or more is lapped using a double-sided lapping device, the processing rate is set to be relatively slow in order to produce a substrate with a warp amount of several tens of μm or less on a desired surface of the substrate. For example, it takes about one hour to process about 60 μm, which raises the problem of increasing the manufacturing cost.

  Further, in order to maintain the flatness of the surface of the surface plate of the double-sided lapping apparatus, a fading operation on the surface of the surface plate is required, so that the maintenance operation is very troublesome.

  The present invention has been made in view of such a point, and in a large-diameter substrate of 4 inches or more, the substrate can be warped to a desired surface side, either the front surface or the back surface, and the amount of warpage can be adjusted. An object is to provide a sapphire substrate manufacturing method and a sapphire substrate.

A method for manufacturing a sapphire substrate according to the present invention is a method for manufacturing a sapphire substrate, which is obtained by slicing from a sapphire ingot and manufacturing a sapphire substrate by subjecting a warped substrate to processing over a plurality of steps. A grinding step for grinding both sides of the substrate, a wet blasting step for wet blasting one or both sides of the substrate after the grinding step, and a substrate holding member for holding the substrate after the wet blasting step An attaching step; a lapping step for lapping the concave surface of the substrate after the affixing step; and a polishing step for CMP polishing the lapped surface of the substrate after the lapping step. The sapphire substrate according to the present invention is manufactured by the above manufacturing method.

  With such a specific matter, a sapphire substrate having a desired amount of warpage on either the front surface or the back surface can be manufactured by a wet blast process.

  In the method for manufacturing the sapphire substrate, in the wet blasting process, the wet blasting may be performed by increasing the processing amount of the concave surface rather than the convex surface of the substrate.

  In this case, since both sides of the substrate are processed and the processing amount of the concave surface is larger than the processing amount of the convex surface, the warpage amount of the concave surface can be finely adjusted.

  Further, it is a method for manufacturing a sapphire substrate, which is obtained by slicing from a sapphire ingot and manufacturing a sapphire substrate by subjecting a warped substrate to processing over a plurality of steps, and a grinding step for grinding both surfaces of the substrate, After the grinding step, an affixing step of adhering the substrate to a substrate holding member that holds the substrate, a lapping step of lapping one side of the substrate after the affixing step, and the lapping of the substrate after the lapping step A polishing step for CMP polishing the processed surface, an annealing step for annealing the substrate subjected to CMP polishing after the CMP polishing step, and wet blasting the concave surface of the annealed substrate after the annealing step A wet blasting process.

  In this case, even if the substrate is heated by the annealing process and the substrate is warped, a sapphire substrate having a desired amount of warpage on either the front surface or the back surface is manufactured by the subsequent wet blasting process. can do.

  In the method for manufacturing the sapphire substrate, the wet blasting may be performed in the wet blasting process until the amount of warpage of the substrate is reduced.

  In this case, since the wet blasting is performed until the warpage amount of the substrate is reduced, the warpage amount can be surely reduced.

  In the method for manufacturing a sapphire substrate, the wet blasting may be continued in the wet blasting process until the warpage of the substrate is reversed.

  In this case, since the wet blasting is continued until the warpage of the substrate is reversed, a sapphire substrate having a warp opposite to the warp direction before the wet blasting process can be manufactured.

  In the sapphire substrate, the amount of warpage of the substrate may be several tens of μm or less.

  In this case, since the amount of warpage of the sapphire substrate is several tens of μm or less, it can be easily grown when a semiconductor layer is grown on the sapphire substrate.

  According to the present invention, in a large-diameter substrate of 4 inches or more, the substrate can be warped to the desired surface side of either the front surface or the back surface, and the method of manufacturing the sapphire substrate capable of adjusting the amount of warpage, and the sapphire substrate Can be provided.

The grinding process of the manufacturing method of the sapphire substrate which concerns on this invention is shown, (a) is a schematic diagram before grinding, (b) is a schematic diagram which shows a grinding process. It is a schematic diagram which shows the wet blasting process of the manufacturing method of the sapphire substrate which concerns on this invention. It is a schematic diagram which shows the wet blast process of the manufacturing method of the sapphire substrate which concerns on this invention, Comprising: (a) is a schematic diagram which shows a mode that the wet blast process is performed to the concave surface of a board | substrate, (b) It is a schematic diagram which shows a mode that the wet blast process is performed to a convex surface. It is sectional drawing which shows the sticking process of the manufacturing method of the sapphire substrate which concerns on this invention. The lapping process of the manufacturing method of the sapphire substrate which concerns on this invention is shown, (a) is a top view which shows the outline of a lapping apparatus, (b) is sectional drawing which shows the outline of a lapping apparatus. The CMP process of the manufacturing method of the sapphire substrate concerning this invention is shown, (a) is a top view which shows the outline of a CMP apparatus, (b) is sectional drawing which shows the outline of a CMP apparatus. It is a manufacturing flow which shows the manufacturing method of a sapphire substrate, (a) is a manufacturing flow which shows one Embodiment of this invention, (b) is a manufacturing flow which shows other embodiment of this invention. It is a manufacturing flow of the conventional sapphire substrate.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 7 is a manufacturing flow showing a method of manufacturing a sapphire substrate, (a) is a manufacturing flow showing an embodiment of the present invention, and (b) is a manufacturing flow showing another embodiment of the present invention.

  The method for manufacturing a sapphire substrate according to the present embodiment is a method for manufacturing a sapphire substrate, which is obtained by slicing from a sapphire ingot, and manufacturing the sapphire substrate by processing the substrate 10 having warpage over a plurality of steps, The substrate 10 is affixed to the substrate holding member 300 that holds the substrate 10 after the grinding step for grinding both sides of the substrate 10, the wet blasting step for wet blasting one or both sides of the substrate 10 after the grinding step, and the wet blasting step. And a lapping step for lapping the concave surface of the substrate 10 after the lapping step, and a polishing step for CMP polishing the lapped surface of the substrate 10 after the lapping step.

  The substrate 10 used in the present invention is, for example, 4 inches, has a thickness of 850 μm, a thickness unevenness of ± 20 μm, and a warpage amount of 20 μm. Here, let the convex surface of the board | substrate 10 immediately after slicing from a sapphire ingot be the surface 10A, and let the concave surface of the board | substrate 10 be the back surface 10B (refer Fig.1 (a)). The back surface 10B of the substrate may be concave and the front surface 10A may be convex.

  Hereinafter, a method for manufacturing a sapphire substrate using the substrate 10 will be described along the steps.

-Grinding process First, a grinding process is demonstrated. FIG. 1 shows a grinding process of a method for manufacturing a sapphire substrate according to the present invention, (a) is a schematic diagram before grinding, and (b) is a schematic diagram showing a grinding process.

  In the grinding step, both sides of the substrate 10 are ground by grinding the substrate 10 one side at a time. Grinding apparatus 600 used in the grinding process confronts ceramic plate 620 on which substrate 10 is placed by suction, ceramic plate 620, grindstone 610 for grinding substrate 10, and vacuum suction of substrate 10 and ceramic plate 620. A vacuum pump (not shown). A plurality of holes (not shown) are formed on the surface of the ceramic plate 620, and these holes are connected to a vacuum pump (see FIG. 1B). The grindstone 610 for grinding the substrate 10 is preferably a diamond grindstone.

  Using the grinding apparatus 600, the surface 10A of the substrate 10 is first ground. The back surface 10 </ b> B of the substrate 10 is attached to the ceramic plate 620 through a suction plate 630 that holds the substrate 10. A plurality of holes (not shown) are also formed in the suction disk 630, and the substrate 10 is sucked by the ceramic plate 620 when the vacuum pump is operated. By this adsorption, the substrate 10 is deformed along the surface shape of the ceramic plate 620.

  With the back surface 10B of the substrate 10 adsorbed to the ceramic plate 620, the surface 10A of the substrate 10 is ground by 25 μm with the grindstone 610. After grinding the surface 10A of the substrate 10, the vacuum suction pump is stopped, the substrate 10 is turned over, and the back surface 10B of the substrate 10 is ground by 25 μm in the same manner as described above. At this time, the processing rate of the substrate is about several tens of μm / min. This is a processing rate several tens of times faster than the prior art.

  Thereby, the thickness of the substrate 10 is ground by 50 μm in total on both sides. That is, the thickness of the substrate 10 at the end of the grinding process is 800 μm. At this time, the thickness unevenness of the substrate 10 is ± 2 μm. Therefore, thickness unevenness is reduced as compared with that before the grinding step. Preferably, the thickness unevenness can be further reduced by grinding the substrate 10 to 100 μm. Here, the amount of warpage of the substrate 10 does not change before and after the grinding process. Further, grinding marks by the grindstone 610 remain on the ground surface (both surfaces of the substrate 10). In order to remove the grinding marks and to set the warpage amount of the substrate 10 to a desired value, the next wet blast process is performed.

  In the present embodiment, the front surface 10A is ground first, but the back surface 10B may be ground first.

-Wet blast process Next, a wet blast process is demonstrated. FIG. 2 is a schematic diagram showing a wet blasting process of the method for manufacturing a sapphire substrate according to the present invention, and FIG. 3 is a schematic diagram showing a wet blasting process of the method for manufacturing a sapphire substrate according to the present invention. These are the schematic diagrams which show a mode that wet blasting is performed on the concave surface of a board | substrate, (b) is a schematic diagram which shows a mode that wet blast processing is performed on the convex surface of a board | substrate.

  A wet blasting apparatus 500 used for wet blasting is disposed so as to face a stage 510 on which a substrate 10 is placed, a stage moving mechanism (not shown) that moves the stage 510 in one direction, and the stage 510. A wet blast nozzle 520 for spraying loose abrasive grains 530 in which loose abrasive grains and compressed air are mixed is provided on 510.

  The wet blast nozzle 520 includes a free abrasive grain introduction part 521 into which free abrasive grains are introduced, an air introduction part 522 into which compressed air is introduced, and a mixing chamber in which the introduced free abrasive grains and compressed air are mixed. 523 and a slit shape in which loose abrasive grains 530 sent together with compressed air from the mixing chamber 523 are jetted on a straight line orthogonal to the moving direction of the stage 510 (the direction indicated by the arrow X in FIG. 2) and the stage 510 in the same plane. The injection part 524 is provided.

  In the present embodiment, the wet blast nozzle 520 is disposed at an angle of 90 ° with the substrate 10, but the angle between the wet blast nozzle 520 and the substrate 10 is not limited to this angle.

  The wet blasting of the substrate 10 is performed using the wet blast apparatus 500. The substrate 10 is placed on the stage 510 so that the back surface 10B (concave surface) of the substrate 10 is wet-blasted toward the wet blast nozzle 520 (see FIG. 3A), and the stage 510 is moved by the stage moving mechanism. While moving at a speed of several mm / sec, free abrasive grains 530 are sprayed vertically from the wet blast nozzle 520 toward the substrate 10 at a pressure of 1 MPa or less. When the stage 510 on which the substrate 10 is placed moves, the free abrasive grains 530 are sprayed on the entire back surface 10B of the substrate 10, so that the entire back surface 10B of the substrate 10 is wet-blasted.

  In wet blast processing, the processing rate is set to a speed of several μm / min. The processing rate of wet blast processing depends on the moving speed of the stage 510. That is, the slower the moving speed of the stage 510, the longer the time during which the substrate 10 is exposed to the loose abrasive grains 530, and the greater the processing amount. Conversely, the faster the moving speed of the stage 510, the shorter the time during which the substrate 10 is exposed to the loose abrasive grains 530, and the smaller the processing amount.

  The amount of processing of the substrate 10 by the wet blasting process is at least 5 μm. When the processing amount is 5 μm or more, grinding marks generated on the substrate 10 in the above-described grinding process can be removed. Further, the surface of the substrate 10 subjected to the wet blast processing is a matte surface (matte surface). This mat surface is made into a specular surface specification by lapping and CMP polishing described later.

  In addition, since the material loss increases when the processing amount is about several tens of μm, it is preferable that the processing amount is as small as possible within a range in which the warpage amount can be adjusted.

  Further, when the processing rate is set to several μm / min and the processing amount is set to several μm, the wet blast processing time is completed in several minutes. Therefore, even if the processing time of the grinding process described above is added, the processing can be performed in a shorter time than when the double-sided lapping apparatus disclosed in the prior art is used.

  In addition, although the wafer size of the substrate 10 of the present embodiment is assumed to be 4 inches, the 6-inch substrate 10 can be wet-blasted using a 6-inch stage. By manufacturing a 6-inch sapphire substrate, more semiconductor elements can be formed on the surface of the sapphire substrate than on a 4-inch sapphire substrate, so that the amount of collected semiconductor elements increases. Therefore, the manufacturing cost can be reduced.

  Moreover, since wet blasting does not require management of the surface plate, maintenance can be easily performed.

  The free abrasive grains used for the free abrasive grains 530 are desirably free abrasive grains having a uniform particle diameter in order to improve the flatness of the substrate 10, and alumina having an average particle diameter of several tens to several hundred μm. Is used.

  By the way, in the above-described wet blasting process, wet blasting was performed only on the back surface 10B (concave surface). Instead, after the surface 10A (convex surface) was first wet blasted, the back surface 10B (concave surface) was wet. Blasting may be performed (see FIG. 3B). In this case, the processing amount for wet blasting may be greater on the back surface 10B (concave surface) than on the front surface 10A (convex surface) of the substrate 10.

-Pasting process Next, a pasting process is explained. FIG. 4 is a cross-sectional view showing the attaching process of the method for manufacturing a sapphire substrate according to the present invention.

  In the attaching step, the substrate holding member 300 is attached to a surface opposite to the surface having the substrate 10 as a mirror surface (in this embodiment, the back surface 10B of the substrate 10) by a lapping step and a CMP step described later.

  The substrate holding member 300 includes a plate 310, a holding member 320 that is fixed on the plate 310 and has an opening, and a suction pad 330 that is accommodated in the opening of the holding member 320 and attached to the plate 310.

  The suction pad 330 is attached to the back surface 10B of the substrate 10, and the holding member 320 and the back surface 10B of the substrate 10 are attached to the back surface 10B of the substrate 10 using wax as an adhesive. It is preferable to apply pressure from the surface 10A of the substrate 10 at the time of pasting.

  As a result, the substrate 10 and the substrate holding member 300 are attached via the plate 310. In addition, as an adhesive agent, an acrylic resin or a glass epoxy resin is mentioned, for example. The plate 310 may be a ceramic plate.

  As described above, since the substrate holding member 300 is attached to the back surface 10B of the substrate 10, the substrate 10 is pressed in the direction of the surface plate 410 when the substrate 10 is lapped in the lapping process described later. However, the substrate 10 can be protected by the substrate holding member 300.

-Lapping process Next, a lapping process is demonstrated. 5A and 5B show a lapping process of the method for manufacturing a sapphire substrate according to the present invention, wherein FIG. 5A is a plan view showing an outline of the lapping apparatus, and FIG. 5B is a cross-sectional view showing an outline of the lapping apparatus.

  In the lapping process, the surface 10A of the substrate 10 described above is lapped. The lapping apparatus 400 used in the lapping process discharges a surface plate 410 for lapping the substrate 10, a fixture 420 to which the substrate 10 is attached so as to face the surface plate 410, and free abrasive grains used during lapping. And a motor (not shown) that rotates independently with the center of the fixture 420 as the rotation axis and the center of the surface plate 410 as the rotation axis. As the surface plate 410, a relatively soft metal-based surface plate containing copper or tin is used.

  The lapping apparatus 400 is used to lapping the substrate 10. After attaching the substrate 10 to which the substrate holding member 300 described above is attached to the fixture 420, the fixture 420 is loaded in the direction of the surface plate 410, whereby the surface 10A of the substrate 10 is pressed against the surface plate 410. .

  In this state, the surface plate 410 and the mounting tool 420 are rotated so as to be opposite to each other, and free abrasive grains are discharged from the nozzle 430. The platen 410 is preferably rotated at a rotational speed of 30 rpm to 80 rpm.

  The loose abrasive has a particle size of several μm, and for example, diamond slurry is used. Thereafter, the surface 10A of the substrate 10 is polished with a soft foamed urethane or a suede type polishing cloth using silica particles having a particle diameter of several tens of nm.

CMP process and precision cleaning process Next, the CMP process will be described. 6A and 6B show the CMP process of the method for manufacturing a sapphire substrate according to the present invention. FIG. 6A is a plan view showing the outline of the CMP apparatus, and FIG. 6B is a cross-sectional view showing the outline of the CMP apparatus.

  In the CMP process, after performing the lapping described above, the surface 10A of the substrate 10 on which lapping has been performed is subjected to CMP polishing.

  The CMP apparatus 450 used in the CMP process and the lapping apparatus 400 described above include a cleaning liquid nozzle 460 that discharges a cleaning liquid for precisely cleaning chemicals such as free abrasive grains, Since only the point of using colloidal silica having a particle diameter of several tens of nanometers is different, only the difference will be described below, and the same components are denoted by the same reference numerals and the description thereof is omitted. .

  In the CMP polishing, the surface plate 410 and the mounting tool 420 are rotated by the rotating shaft of the surface plate 410 and the rotating shaft of the mounting tool 420, and free abrasive grains are discharged from the nozzle 430 to perform the CMP polishing. After that, the cleaning nozzle is used to remove foreign substances such as polishing scraps (scraps such as workpieces and polishing pads) and aggregates of loose abrasive grains, and cleaning colloidal silica, which is an alkaline chemical. While discharging from 460, the surface 10A of the substrate 10 is precisely cleaned.

  As a result, a sapphire substrate having a matte surface (matte surface) after the wet blasting process described above and a mirror surface specification after the precision cleaning process can be manufactured.

  Next, Examples 1 to 7 of the wet blasting process in the embodiment described above will be described.

  In Examples 1 to 7, a grinding process is performed on a substrate having a thickness of 850 μm, a thickness unevenness of ± 20 μm, and a warpage amount in the direction of the surface 10A of 20 μm. The thickness is 750 μm, the thickness unevenness is ± 2 μm, and the surface 10A side. Wet blasting was performed on the substrate 10 in which the amount of warpage in the direction was 20 μm (surface 10A was convex).

  In Examples 1 to 4, as shown in FIG. 3A, wet blasting is performed only on the back surface 10B (concave surface) of the substrate 10, and in Examples 5 to 7, FIGS. As shown in FIG. 2B, after wet blasting was first performed on the front surface 10A (convex surface) of the substrate 10, wet blasting was performed on the back surface 10B (concave surface). In Examples 5 to 7, the amount of processing by wet blasting was greater on the back surface 10B (concave surface) than on the front surface 10A (convex surface) of the substrate 10.

[Example 1]
As a result of performing wet blast processing on the back surface 10B of the substrate 10 by 5 μm, it was possible to manufacture the substrate 10 that was warped by 2 μm in the direction of the back surface 10B side of the substrate 10 as opposed to before processing.

[Example 2]
As a result of performing wet blast processing on the back surface 10B of the substrate 10 by 7 μm, it was possible to manufacture the substrate 10 that was warped by 5 μm in the direction of the back surface 10B side of the substrate 10 as opposed to before processing.

[Example 3]
As a result of performing wet blast processing on the back surface 10B of the substrate 10 by 9 μm, it was possible to manufacture the substrate 10 that was warped by 10 μm in the direction of the back surface 10B side of the substrate 10 as opposed to before processing.

[Example 4]
As a result of performing wet blast processing on the back surface 10B of the substrate 10 by 11 μm, it was possible to manufacture the substrate 10 that was warped by 15 μm in the direction of the back surface 10B side of the substrate 10 as opposed to before processing.

[Example 5]
After performing wet blasting on the front surface 10A of the substrate 10 for 5 μm and further performing wet blasting on the back surface 10B of the substrate 10 for 7 μm, the substrate 10 warped by 1 μm in the direction toward the back surface 10B of the substrate 10 as opposed to before processing. Could be manufactured.

[Example 6]
After performing wet blasting on the front surface 10A of the substrate 10 for 5 μm and further performing wet blasting on the back surface 10B of the substrate 10 for 9 μm, the substrate 10 warped by 4 μm in the direction toward the back surface 10B of the substrate 10 as opposed to before processing. Could be manufactured.

[Example 7]
After performing wet blasting on the front surface 10A of the substrate 10 for 5 μm and further performing wet blasting on the back surface 10B of the substrate 10 for 11 μm, the substrate 10 warped by 12 μm in the direction toward the back surface 10B of the substrate 10 as opposed to before processing. Could be manufactured.

  From Examples 1 to 7 above, the substrate 10 that warped 20 μm toward the front surface 10A side of the substrate 10 before the wet blasting process becomes the substrate 10 that warped 15 μm or less toward the back surface 10B side of the substrate 10 after the wet blasting process. It can be seen that the amount of warpage could be reduced.

  Thereby, a sapphire substrate having a desired amount of warpage on either the front surface 10A or the back surface 10B can be manufactured by the wet blasting process, and the amount of warpage can be set to several tens of μm or less. did it.

  Further, by processing both surfaces of the substrate 10 and increasing the processing amount of the back surface 10B (concave surface) from the front surface 10A (convex surface), the warpage amount of the back surface (concave surface) can be finely adjusted and the warpage of the substrate 10 can be adjusted. Could be reversed before and after the wet blasting process.

[Other Embodiments]
Next, another embodiment of the present invention will be described with reference to the drawings.

  FIG.7 (b) is a manufacturing flow which shows other embodiment of the manufacturing method of the sapphire substrate based on this invention.

  The method for manufacturing a sapphire substrate according to the present embodiment is a method for manufacturing a sapphire substrate, which is obtained by slicing from a sapphire ingot and manufacturing a sapphire substrate by performing processing over a plurality of steps on a warped substrate, A grinding step for grinding both surfaces of the substrate; a pasting step for pasting the substrate to a substrate holding member that holds the substrate after the grinding step; and a lapping step for lapping one side of the substrate after the grinding step; After the lapping step, a polishing step for CMP polishing the lapped surface of the substrate; an annealing step for annealing the CMP polished substrate after the CMP polishing step; and after the annealing step, the annealing is performed. And a wet blasting process for wet blasting the concave surface of the substrate.

  In the manufacturing flow according to the present embodiment, the grinding process, the wet blasting process, the attaching process, the lapping process, the CMP process, and the precision cleaning process are performed according to the manufacturing flow according to the previous embodiment shown in FIG. Since these steps are the same as those in FIG. 2, the description of the overlapping steps is omitted here, and only the annealing step will be described.

-Annealing process The annealing process performed after the CMP process in the manufacturing method of the sapphire substrate of this invention is demonstrated.

  In the annealing process, the processing stress and the processing distortion generated in the substrate 10 by the above-described grinding process, lapping process, and CMP process are alleviated. Specifically, the substrate 10 is placed in a high temperature furnace (not shown) and held at a heating temperature of 1600 ° C. for 3 hours.

  Thereby, the processing stress and processing distortion of the substrate 10 can be relaxed.

  The annealing temperature and annealing time described above are merely examples, and are not limited to the above examples.

  Next, Examples 8 to 10 of the wet blast process in the present embodiment will be described.

  In Examples 8 to 10, the annealing process is performed along the manufacturing flow shown in FIG. 7B, and the back surface 10 </ b> B (concave surface) of the substrate 10 in which the surface 10 </ b> A warped by 2 μm on the front surface 10 </ b> A side is a convex surface. Wet blasting was performed.

[Example 8]
As a result of processing the back surface 10B of the substrate 10 by 2 μm by wet blasting with respect to the substrate 10 warped by 2 μm on the front surface 10A side of the substrate 10, a substrate that is warped by 3 μm on the back surface 10B side of the substrate 10 is manufactured contrary to before processing. We were able to.

[Example 9]
As a result of processing the back surface 10B of the substrate 10 by 4 μm by wet blasting with respect to the substrate 10 warped by 2 μm on the front surface 10A side of the substrate 10, a substrate that is warped 8 μm on the back surface 10B side of the substrate 10 is manufactured contrary to before processing. We were able to.

[Example 10]
As a result of processing the back surface 10B of the substrate 10 by 6 μm by wet blasting with respect to the substrate 10 warped by 2 μm on the front surface 10A side of the substrate 10, a substrate having a curvature of 11 μm on the back surface 10B side of the substrate 10 is manufactured contrary to before processing. We were able to.

  In Examples 8 to 10 described above, a substrate warped by 2 μm on the front surface 10A side of the substrate 10 before the wet blasting process, and a substrate having a warpage amount of 15 μm or less on the back surface 10B side of the substrate 10 after the wet blasting process. We were able to.

  Thus, even if the substrate 10 is heated by the annealing process and the substrate 10 is warped, a sapphire substrate having a desired warping amount can be manufactured on the desired surface of the substrate 10 by the subsequent wet blasting process. did it.

  The above-described embodiments and examples of the present invention are all examples of the present invention, and are not of a nature that limits the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Substrate 10A Front surface 10B Back surface 300 Substrate holding member 400 Lapping device 450 CMP device 500 Wet blast device 600 Grinding device

Claims (7)

A method for producing a sapphire substrate, which is obtained by slicing from a sapphire ingot and producing a sapphire substrate by subjecting a substrate having warpage to processing over a plurality of steps,
A grinding step of grinding both sides of the substrate;
After the grinding step, a wet blasting step of wet blasting one or both sides of the substrate;
After the wet blasting step, an attaching step of attaching the substrate to a substrate holding member that holds the substrate;
After the attaching step, a lapping step for lapping the concave surface of the substrate;
After the lapping step, a polishing step for CMP polishing the lapped surface of the substrate;
A method for manufacturing a sapphire substrate, comprising: A method for producing a sapphire substrate according to claim 1,
In the wet blasting process, the wet blasting process increases the amount of processing on the concave surface side of the convex surface side of the substrate. A method for producing a sapphire substrate, which is obtained by slicing from a sapphire ingot and producing a sapphire substrate by subjecting a substrate having warpage to processing over a plurality of steps,
A grinding step of grinding both sides of the substrate;
After the grinding step, an attaching step of attaching the substrate to a substrate holding member that holds the substrate;
After the attaching step, a lapping step for lapping one side of the substrate;
After the lapping step, a polishing step for CMP polishing the lapped surface of the substrate;
After the CMP polishing step, an annealing step for annealing the substrate that has been subjected to CMP polishing; and
A wet blasting step for performing wet blasting on the concave surface of the annealed substrate after the annealing step;
A method for manufacturing a sapphire substrate, comprising: A method for producing a sapphire substrate according to any one of claims 1 to 3,
In the wet blasting process, the wet blasting is performed until the amount of warpage of the substrate is reduced. A method for producing a sapphire substrate according to any one of claims 1 to 3,
In the wet blasting process, the wet blasting is continued until the warpage of the substrate is reversed.   The sapphire substrate manufactured by the manufacturing method of the sapphire substrate of any one of Claim 1 to 5.   The sapphire substrate according to claim 6, wherein the amount of warpage of the substrate is several tens of μm or less.

Images