JP2010056366A - Grinder of wafer, and manufacturing method of semiconductor light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinder or the like capable of grinding a substrate of a wafer in a uniform thickness. <P>SOLUTION: The grinder II of a wafer 10 is provided with a substrate 10a and a compound semiconductor layer formed on the substrate 10a. The grinder ll of the wafer 10 includes: a grinding surface plate 34 having a grinding plane 34 for grinding the substrate 10a of the wafer 10; a carrier plate (fixing plate) 31 arranged so as to face the grinding plane 34a of the grinding surface plate 34 and fixing the wafer 10 so that the substrate 10a of the wafer 10 faces the grinding plane 34a; and a pressing member 20 changing a shape of the carrier plate 31 so as to copy a shape of the grinding plane 34a of the grinding surface plate 34 and applying pressure to make the substrate 10a of the wafer 10 contact with the grinding plane 34a through the carrier plate 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wafer grinding apparatus, and more particularly, to a wafer grinding apparatus for a wafer having a compound semiconductor layer. The present invention also relates to a method for manufacturing a semiconductor light emitting device.

  In general, a semiconductor light emitting device having a compound semiconductor layer such as a group III compound semiconductor layer is prepared by forming a compound semiconductor layer on a substrate made of a sapphire single crystal or the like, and further preparing a wafer provided with a positive electrode, a negative electrode, etc. It is prepared by grinding and polishing the surface to be ground of the substrate (see Patent Documents 1 and 2).

Japanese Patent No. 3026087 JP 2003-347255 A

By the way, when grinding / polishing the substrate of the semiconductor light emitting device, the wafer to be ground is usually ground by rotating the wafer attached to the grinding machine while being pressed against the disk-shaped grinding surface plate with a predetermined pressure.
However, as the grinding process proceeds, the thickness of the central portion of the grinding surface plate decreases, and the grinding surface plate may be deformed into a mortar shape.
If the grinding operation is continued while the grinding platen is deformed into a mortar shape, the surface to be ground of the substrate is more easily ground than the portion pressed against the outer peripheral side of the grinding platen than the portion pressed against the inner peripheral side. As a result, there is a problem that the surface to be ground of the substrate is ground in a tapered shape, and the thickness of the substrate is not uniform.

  An object of the present invention is to provide a grinding apparatus or the like capable of grinding a wafer substrate to a uniform thickness.

  Thus, according to the present invention, there is provided a wafer grinding apparatus having a substrate and a compound semiconductor layer formed on the substrate, the grinding surface plate having a grinding surface for grinding the substrate of the wafer, and the grinding surface plate The fixing plate is arranged so as to face the grinding surface of the wafer and fixes the wafer so that the substrate of the wafer faces the grinding surface, and the shape of the fixing plate is deformed and the pressure is applied to follow the shape of the grinding surface of the grinding surface plate. And a pressure contact member for bringing the wafer substrate into contact with the grinding surface via a fixed plate.

Here, in the wafer grinding apparatus to which the present invention is applied, the pressure contact member that applies pressure to bring the wafer substrate into contact with the grinding surface is a pressure having a space closed by an elastic member provided to contact the fixed plate. It is preferable to provide a chamber.
In this case, it is preferable to have a pressurized fluid supply means for supplying pressurized fluid to the pressure chamber.
The elastic member used when forming the pressure chamber is preferably made of silicone rubber.

  Next, according to the present invention, there is provided a method for manufacturing a semiconductor light emitting device having a substrate and a compound semiconductor layer formed on the substrate, wherein the wafer includes the substrate and the compound semiconductor layer formed on the substrate. The bonding process of fixing the wafer to the fixed plate by bonding the compound semiconductor layer side to the fixed plate of the grinding device, and the substrate of the wafer so that the wafer substrate faces the grinding platen of the grinding device A pressure contact process in which the shape of the fixed plate is deformed to follow the shape of the grinding surface of the grinding surface plate and the wafer substrate is brought into contact with the grinding surface plate by applying pressure, and the grinding surface plate And a grinding step of grinding the substrate of the wafer brought into contact with the semiconductor light emitting device.

Here, in the method for manufacturing a semiconductor light emitting device to which the present invention is applied, it is preferable to increase the pressure for pressing the fixing plate according to the deformation amount of the grinding platen.
It is preferable that a wafer attached to a grinding apparatus and whose substrate is ground is attached to a fixing plate via Japanese paper and a fixing agent.

  According to the present invention, the wafer substrate can be ground to a uniform thickness.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary. Further, the drawings to be used are for explaining the present embodiment and do not represent the actual size.

(Semiconductor light emitting device)
The semiconductor light emitting device used in this embodiment usually has a predetermined substrate and a compound semiconductor layer formed on the substrate. Examples of the compound semiconductor constituting the compound semiconductor layer include a III-V group compound semiconductor, a II-VI group compound semiconductor, a IV-IV group compound semiconductor, and the like. In the present embodiment, a III-V group compound semiconductor is preferable, and among these, a group III nitride compound semiconductor is preferable. Hereinafter, a semiconductor light emitting device having a group III nitride compound semiconductor will be described as an example.

FIG. 1 is a diagram illustrating a stacked semiconductor which is an example of a semiconductor light emitting element used in this embodiment. As shown in FIG. 1, the laminated semiconductor I has an n-type semiconductor layer 14, a light emitting layer 15, and a p-type semiconductor layer 16 sequentially laminated on an intermediate layer 12 formed on a substrate surface 11 a of a substrate 11. These constitute a compound semiconductor layer (group III compound semiconductor layer) 17.
The n-type semiconductor layer 14 includes a base layer 13 made of a group III compound semiconductor, an n-type contact layer 14a, and an n-type cladding layer 14b. The light emitting layer 15 has a structure in which barrier layers 15a and well layers 15b are alternately stacked. In the p-type semiconductor layer 16, a p-type cladding layer 16a and a p-type contact layer 16b are stacked.

Examples of the material constituting the substrate 11 include sapphire, silicon carbide (silicon carbide: SiC), silicon, zinc oxide, magnesium oxide, manganese oxide, zirconium oxide, manganese zinc iron oxide, magnesium aluminum oxide, zirconium boride, and oxidation. Examples include gallium, indium oxide, lithium gallium oxide, lithium aluminum oxide, neodymium gallium oxide, lanthanum strontium aluminum tantalum, strontium titanium oxide, titanium oxide, hafnium, tungsten, and molybdenum.
Among these, sapphire and silicon carbide (silicon carbide: SiC) are preferable.

  The intermediate layer 12 preferably contains A1, and particularly preferably contains A1N which is a group III nitride. The material constituting the intermediate layer 12 is not particularly limited as long as it is a group III nitride semiconductor represented by the general formula A1GaInN. Furthermore, As and P may be contained as a group V. In the case where the intermediate layer 12 has a composition containing A1, GaA1N is preferable, and the composition of A1 is preferably 50% or more.

  As a material used for the underlayer 13, a group III nitride (GaN-based compound semiconductor) containing Ga is used, and in particular, A1GaN or GaN can be suitably used. The film thickness of the underlayer 13 is 0.1 μm or more, preferably 0.5 μm or more, more preferably 1 μm or more.

(N-type semiconductor layer 14)
The n-type semiconductor layer 14 includes an n-type contact layer 14a and an n-type cladding layer 14b. As the n-type contact layer 14a, a GaN-based compound semiconductor is preferably used in the same manner as the base layer 13. Moreover, it is preferable that the gallium nitride compound semiconductor which comprises the base layer 13 and the n-type contact layer 14a is the same composition, The total film thickness of these is 0.1 micrometer-20 micrometers, Preferably it is 0.5 micrometer-15 micrometers, Preferably, it is set in the range of 1 μm to 12 μm.

  The n-type cladding layer 14b can be formed of A1GaN, GaN, GaInN, or the like. Alternatively, a heterojunction of these structures or a superlattice structure in which a plurality of layers are stacked may be used. In the case of GaInN, it is desirable to make it larger than the GaInN band gap of the light emitting layer 15. The film thickness of the n-type cladding layer 14b is preferably in the range of 5 nm to 500 nm, more preferably 5 nm to 100 nm.

(Light emitting layer 15)
The light emitting layer 15 includes a barrier layer 15a made of a gallium nitride-based compound semiconductor and a well layer 15b made of a gallium nitride-based compound semiconductor containing indium, which are alternately stacked. The barrier layers 15a are stacked in the order in which the barrier layers 15a are arranged on the type semiconductor layer 16 side. In the present embodiment, the light emitting layer 15 includes six barrier layers 15a and five well layers 15b that are alternately and repeatedly stacked, and the barrier layer 15a is disposed on the uppermost layer and the lowermost layer of the light emitting layer 15, A well layer 15b is arranged between the barrier layers 15a.

The barrier layer 15a, for example, the well layer 15b larger bandgap energy _{A1 c Ga 1-c N (} 0 ≦ c ≦ 0.3) than that of a gallium nitride-based compound semiconductor containing indium gallium nitride, such as A compound semiconductor can be suitably used.
Furthermore, the well layer 15b can be formed using indium as the semiconductor gallium nitride-based compound containing, for _example, can be used _{Ga 1-s In s N (} 0 <s <0.4) GaN such as indium.
The film thickness of the entire light emitting layer 15 is not particularly limited, but is preferably a film thickness that can obtain a quantum effect, that is, a critical film thickness region. For example, the thickness of the light emitting layer 15 is preferably in the range of 1 nm to 500 nm, and more preferably about 100 nm.

(P-type semiconductor layer 16)
The p-type semiconductor layer 16 includes a p-type cladding layer 16a and a p-type contact layer 16b. As the p-type cladding layer 16a, preferably, one having A1 _d Ga _1-d N (0 <d ≦ 0.4) is mentioned. The film thickness of the p-type cladding layer 16a is preferably 1 nm to 400 nm, more preferably 5 nm to 100 nm.
The a p-type contact layer 16b, at least _{A1 e Ga 1-e N (} 0 ≦ e <0.5) comprising gallium nitride-based compound semiconductor layer. The film thickness of the p-type contact layer 16b is not particularly limited, but is preferably 10 nm to 500 nm, and more preferably 50 nm to 200 nm.

(Manufacturing method of semiconductor light emitting device)
In the present embodiment, the compound semiconductor light emitting device is usually manufactured by the following procedure. First, an intermediate layer 12 made of a group III nitride is formed on a substrate 11 by causing a gas containing a group V element and a metal material to react with each other and reacting with plasma. The underlayer 13, the n-type semiconductor layer 14, the light emitting layer 15, and the p-type semiconductor layer 16 are sequentially stacked.
Here, when the group III nitride semiconductor crystal is epitaxially grown on the substrate 11, for example, a sputtering method or the like is used to form the intermediate layer 12 by depositing the material activated and reacted with plasma on the substrate 11. .
After the intermediate layer 12 is formed by sputtering, an n-type semiconductor layer 14, a light emitting layer 15, and a p-type semiconductor layer 16 are sequentially formed thereon by metal organic chemical vapor deposition (MOCVD).
In addition, after forming the base layer 13 of the n-type semiconductor layer 14 among the compound semiconductor layers 17 by MOCVD, each layer of the n-type contact layer 14a and the n-type cladding layer 14b is formed by sputtering, and light emission thereon. The layer 15 may be formed by MOCVD, and the p-type cladding layer 16a and the p-type contact layer 16b constituting the p-type semiconductor layer 16 may be formed by reactive sputtering.

  Then, after the intermediate layer 12 and the compound semiconductor layer 17 are formed on the substrate 11, a translucent positive electrode (not shown) is laminated on the p-type semiconductor layer 16 of the compound semiconductor layer 17, and positive electrode bonding is performed thereon. A pad (not shown) is formed. Further, a wafer is formed in which an exposed region (not shown) formed in the n-type contact layer 14a of the n-type semiconductor layer 14 is provided with a negative electrode (not shown). Thereafter, the ground surface of the substrate 11 is ground and polished, and then cut into, for example, a 350 μm square to form a compound semiconductor light emitting element.

(Wafer grinding equipment)
Next, a wafer grinding apparatus will be described.
FIG. 2 is a diagram illustrating a wafer grinding apparatus to which the present embodiment is applied. As shown in FIG. 2A, the grinding apparatus II is disposed to face a grinding surface plate 34 having a grinding surface 34a for grinding the substrate 10a of the wafer 10 and the grinding surface 34a of the grinding surface plate 34. The carrier plate 31 is deformed so as to follow the shape of the carrier plate (fixing plate) 31 that fixes the wafer 10 so that the substrate 10a of the wafer 10 faces the grinding surface 34a and the grinding surface 34a of the grinding surface plate 34. The pressure contact member 20 applies pressure to bring the substrate 10a of the wafer 10 into contact with the grinding surface 34a via the carrier plate 31.

  The pressure contact member 20 includes a main body 21 and an elastic member 22 attached to the lower side of the main body 21 in contact with the carrier plate 31. As shown in FIG. 2A, the main body 21 is formed with a pressure chamber 23 having a space closed by an elastic member 22. The pressure contact member 20 brings the substrate 10a of the wafer 10 into contact with the grinding surface 34a of the grinding surface plate 34 via the carrier plate 31 by the pressure contact means 40 placed on the upper surface of the pressure contact member 20 (pressure contact).

The grinding apparatus II also leaks pressurized fluid from the pressurized fluid supply means 50 for supplying pressurized fluid such as pressurized air to the pressure chamber 23 of the pressure contact member 20 and the pressure chamber 23 formed in the pressure contact member 20. And a pressurized fluid leakage means 60 that acts as pressure variable means for varying the pressure when the wafer 10 is brought into pressure contact with the grinding surface plate 34.
Although not shown, the grinding apparatus II is disposed below the grinding surface plate 34 and rotates the grinding surface plate 34 and the grinding surface plate rotation driving means, and is disposed above the pressure contact member 20 and moves the pressure contact member 20 up and down. A vertical movement means and a rotation driving means for rotating the carrier plate 31 and the wafer 10 by rotating the pressure contact member 20 are provided.

The grinding surface plate 34 usually has a disk shape, and the upper surface of the grinding surface plate 34 becomes a grinding surface 34 a for grinding the substrate 10 a of the wafer 10.
In the present embodiment, the carrier plate 31 is formed in a disk shape having a uniform thickness with ceramics having a high rigidity and a high Young's modulus, and a plurality of wafers 10 are formed on a plate surface (pressing surface: lower surface) 31a. Attached and held by gluing.

The main body 21 of the pressure contact member 20 has a disk-like shape that is substantially the same size as the carrier plate 31, and is annular with a flat plate portion 21 a that is formed by providing a cylindrical recess 21 c centered on the axis on the lower surface. It is comprised with the edge part 21b. An annular receiving groove 21d that opens downward is provided on the lower surface of the annular edge portion 21b. As will be described later, the elastic member 22 is attached to the annular housing groove 21d, and the pressure chamber 23 is formed.
The flat plate portion 21a includes a supply communication passage 21e that communicates with the pressure chamber 23 in the axial center, and a plurality of leakage communication passages 21f that communicate with the pressure chamber 23 at equal intervals on a concentric circle centered on the supply communication passage 21e. Is provided.

The elastic member 22 is usually formed of a material having a high coefficient of friction, and a part of the elastic member 22 protrudes from the annular housing groove 21d and is attached to the annular housing groove 21d, and the lower end of the elastic ring portion 22a is closed. And an elastic film 22b. Examples of the material constituting the elastic member 22 include synthetic rubber and the like, specifically, silicone rubber and the like.
When the elastic ring portion 22a of the elastic member 22 is attached to the annular accommodating groove 21d of the pressure contact member 20, a space closed by the elastic member 22 and the main body 21, that is, the pressure chamber 23 is formed.

  The pressure contact means 40 is placed on the upper surface (mounting surface) of the pressure contact member 20, and presses the substrate 10 a of the wafer 10 to the grinding surface 34 a of the grinding surface plate 34 via the pressure contact member 20 and the carrier plate 31. For example, it is composed of a weight. Note that the pressure contact means 40 may be configured to utilize, for example, a fluid pressure by a cylinder in addition to the weight.

The pressurized fluid supply means 50 includes an air compressor 51 that is a pressurizer that supplies pressurized air as a pressurized fluid, a pressure regulator 52 that adjusts the pressure of the pressurized air from the air compressor 51, and a pressure regulator. An air filter 53 that filters and purifies the pressurized air from 52 and a supply communication passage 21 e through which the pressurized air is supplied from the air filter 53 to the pressure chamber 23 of the pressure contact member 20.
A predetermined vertical movement means (not shown) is connected between the air filter 53 of the pressurized fluid supply means 50 and the supply communication path 21e provided in the main body 21 of the pressure contact member 20 and connected to the pressure regulator 52. It is connected by piping arranged in the shaft and a rotary joint (not shown) connected to the supply communication path 21e.
The pressurized fluid leakage means 60 includes a plurality of leakage communication passages 21f provided in the main body 21 of the pressure contact member 20, and a flow rate adjustment valve 61 as a flow rate regulator for adjusting the flow rate of pressurized air leaked from the leakage communication passage 21f. It consists of

Next, the operation of the wafer grinding apparatus II will be described.
First, a plurality of wafers 10 (four in this embodiment, as will be described later) on the plate surface 31a of the carrier plate 31, and the compound semiconductor layer 17 (see FIG. 1) side of the wafer 10 is the side of the grinding apparatus II. The wafer 10 is fixed to the carrier plate 31 by applying wax as a fixing agent to the carrier plate 31 and sticking it on the concentric circles (sticking step). Next, the carrier plate 31 is placed on the grinding surface plate 34 with the plate surface 31 a of the carrier plate 31 facing down and the substrate 10 a of the wafer 10 facing the grinding surface 34 a of the grinding surface plate 34. Then, a predetermined vertical movement means (not shown) is operated to lower the pressure contact member 20, and the bottom surface of the pressure contact member 20 is adjusted so that the axis center of the carrier plate 31 is aligned with the axis center of the pressure contact member 20. The elastic member 22 attached to the carrier plate 31 is brought into contact with the carrier plate 31.

Next, a weight as a pressure contact means 40 is placed on the upper surface of the pressure contact member 20, the elastic member 22 is pressed against the carrier plate 31, and the elastic ring portion 22 a of the elastic member 22 is annularly accommodated in the pressure contact member 20. Airtightness of the pressure chamber 23 is ensured by being brought into pressure contact with the groove 21d.
Further, the air compressor 51 is operated, and the pressure regulator 52 and the flow rate adjustment valve 61 are adjusted to supply pressurized air having a predetermined pressure to the pressure chamber 23, so that a uniform load is applied to the elastic member 22. At the same time, predetermined grinding surface plate rotation driving means (not shown) and carrier plate rotation driving means (not shown) are operated to rotate the grinding surface plate 34 in the direction of arrow A, and the pressure contact member 20 and the carrier plate 31. And the substrate 10a of each wafer 10 is ground. At this time, in the step of grinding the substrate 10a of the wafer 10, a slurry-like predetermined grinding / polishing material is supplied to a portion where the grinding surface 34a of the grinding surface plate 34 and the substrate 10a of the wafer 10 are slid together.

The pressure in the pressure chamber 23 is finely adjusted by the pressurized fluid leakage means 60 that leaks pressurized air as the pressurized fluid. In the present embodiment, by providing a plurality of flow rate adjustment valves 61, the flow rate of the pressurized air that leaks from the pressure chamber 23 is adjusted to adjust the pressure in the pressure chamber 23.
In the present embodiment, the pressure in the pressure chamber 23 can be adjusted by the pressure regulator 52 and the flow rate adjustment valve 61 in this way, and the substrate 10a of the wafer 10 can be uniformly ground.

Next, FIG.2 (b) is a figure explaining the case where the grinding surface 34a of the grinding surface plate 34 deform | transforms into a mortar type | mold by the grinding process progressing.
As described above, when the grinding process of the substrate 10a of the wafer 10 made of a hard material such as sapphire is continued, the grinding surface plate 34 is also ground, and the grinding surface 34a has a mortar shape as shown in FIG. It may be deformed. Here, the mortar type means that the thickness of the inner peripheral portion of the grinding surface 34a is smaller than the thickness of the outer peripheral portion.
In this case, the carrier plate 31 to which the wafer 10 is fixed is pressed against the grinding surface plate 34 in a flat shape as shown in FIG. 2A, and the grinding surface plate 34 is rotated in the direction of arrow A and the pressure contact member 20 and the carrier When the plate 31 is rotated and the grinding operation of the wafer 10 is continued, the substrate 10a of the wafer 10 is ground more excessively than the portion pressed against the outer peripheral side of the grinding surface plate 34 than the portion pressed against the inner peripheral side. easy. As a result, the substrate 10a of the wafer 10 tends to be ground in a tapered shape.

  In the present embodiment, the air compressor 51 is operated, and the pressure regulator 52 and the flow rate adjustment valve 61 are adjusted to increase the pressure in the pressure chamber 23. When the pressure in the pressure chamber 23 increases, a positive pressure is applied to the elastic member 22 attached to the lower side of the pressure contact member 20 from the inside to the outside of the pressure chamber 23 in which airtightness is maintained. Therefore, the elastic member 22 is deformed so that the central portion of the elastic film 22b protrudes outside the pressure chamber 23 in a state where the elastic ring portion 22a is fixed to the annular housing groove 21d, and the carrier plate that contacts the elastic member 22 31 is pressed.

As a result, the shape of the carrier plate 31 is concave as compared with the shape of the grinding surface 34a of the grinding platen 34 deformed into a mortar shape, so that the center portion of the carrier plate 31 is curved from the outer peripheral portion (FIG. 2B). ) Is deformed to be convex downward.
As a result, the substrate 10a of the wafer 10 fixed to the plate surface 31a of the carrier plate 31 is pressed into contact with the deformed grinding surface 34a of the grinding surface plate 34 so as to be substantially parallel. For this reason, the substrate 10a of the wafer 10 can be ground to a uniform thickness without being ground in a tapered shape.

  As described above, in the present embodiment, the pressure for pressing the carrier plate 31 is increased according to the deformation amount of the grinding surface plate 34. The pressure for pressing the carrier plate 31 is appropriately selected depending on the number of times the grinding process is performed on the wafer 10, the time, the number, etc., and is not particularly limited. For example, a method of increasing the pressure according to the deformation amount of the grinding surface plate 34 measured after a certain grinding process is performed, or an empirical method such as increasing the pressure by a predetermined amount after the grinding process is performed a predetermined number of times. Simple operation.

Next, a method for fixing the wafer 10 to the carrier plate 31 will be described.
FIG. 3 is a view for explaining a preferred method of attaching the wafer 10 used in the present embodiment to the grinding apparatus II. FIG. 3A is a diagram illustrating a state in which the wafer 10 is adhered to the carrier plate (fixed plate) 31. FIG. 3B is a diagram illustrating a state in which the carrier plate 31 with the wafer 10 attached is placed on the grinding surface 34 a of the grinding surface plate 34.
As shown in FIG. 3A, a wafer 10 formed by laminating a compound semiconductor layer 17 (see FIG. 1) made of a group III nitride semiconductor on a substrate 10a is composed of a Japanese paper sheet (Japanese paper) 32 and a fixing paper. Four wafers 10 are bonded to a plate surface 31a of a carrier plate 31 formed in a disk shape through a wax (fixing material) 33. The four wafers 10 are stuck on concentric circles of the plate surface 31a so that the substrate 10a is exposed (in FIG. 3A, upward).

  The wafer 10 is attached to the plate surface 31a of the carrier plate 31 by the following procedure. First, the fixing wax 33 is uniformly applied onto the compound semiconductor layer 17 (see FIG. 1) made of a group III nitride semiconductor of the wafer 10 by using, for example, a spin coater. Next, the Japanese paper sheet 32 is placed on the applied fixing wax 33, and the fixing wax 33 is applied onto the Japanese paper sheet 32.

  Subsequently, volatile components such as a solvent contained in the fixing wax 33 are volatilized by baking with a predetermined heating device (not shown). Next, the wafer 10 is adhered to the plate surface 31a of the carrier plate 31 heated to a predetermined temperature so that the substrate 10a is exposed. At this time, the carrier plate 31 is usually heated to about 20 ° C. to 50 ° C. higher than the softening point of the resin as the main component of the fixing wax 33. Thereafter, the carrier plate 31 is cooled by cooling or the like, whereby the resin contained in the fixing wax 33 is solidified and the wafer 10 is fixed to the plate surface 31a. In the present embodiment, the thickness of the two-layer fixing wax 33 and the Japanese paper sheet 32 is 30 μm to 50 μm.

Next, as shown in FIG. 3B, the substrate 10 a of the wafer 10 and the grinding surface 34 a of the grinding surface plate 34 are opposed to each other, and the carrier plate 31 to which the wafer 10 is adhered is placed on the grinding surface plate 34. .
Subsequently, the carrier plate 31 is lowered by a predetermined vertical movement means (not shown), the substrate 10a of the wafer 10 is brought into contact with the grinding surface 34a of the grinding surface plate 34, and the pressure contact member 20 (see FIG. 2A). ), The substrate 10a of the wafer 10 is pressed against the grinding surface 34a with the pressure P.
In this embodiment, the pressure P is pressed against the wafer 10 is pressurized by adjusting the range of ^{70kg / cm 2 ~100kg / cm 2} , the substrate 10a of the wafer 10 on the grinding surface 34a.
Then, the carrier plate 31 and the grinding surface plate 34 are rotated in the direction of arrow A by a predetermined rotation driving means (not shown), and the substrate 10a of each wafer 10 is ground.

  In the present embodiment, the substrate 10a of the wafer 10 is ground by a grinding process of about 20 minutes, and the thickness of the substrate 10a of the wafer 10 is reduced from about 900 μm to about 120 μm. Furthermore, in the present embodiment, following the grinding process, the thickness of the substrate 10a of the wafer 10 is polished from about 120 μm to about 80 μm by a polishing process for about 15 minutes.

  As described above, when the substrate 10a of the wafer 10 having the compound semiconductor layer 17 (see FIG. 1) is ground, the wafer 10 is adhered to the carrier plate 31 of the grinding apparatus via the Japanese paper sheet 32 together with the predetermined fixing wax 33. Thus, even if the substrate 10a of the wafer 10 is warped, or even if the flakes generated by the film forming operation of the compound semiconductor layer 17 (see FIG. 1) remain, the substrate The substrate 10a of the wafer 10 can be ground to a predetermined thickness without causing cracks in 10a.

The fixing wax 33 can be temporarily fixed and fixed so that the wafer 10 does not move to the carrier plate 31 during the grinding process, and the wafer 10 can be easily peeled off from the carrier plate 31 after the grinding process. There is no particular limitation as long as it is possible.
Examples of the fixing wax 33 include, for example, vinyl polymer compounds, petroleum resins, natural resins such as rosin and derivatives thereof, thermoplastic resins such as paraffin wax, fatty acid esters of polyglycerol, and polyglycerol. And an adduct of ethylene oxide or propylene oxide.
In particular as rosin, rosin mainly three-membered ring compound represented by abietic acid (a monocarboxylic acid having a molecular formula C ₂₀ H ₃₀ O _2), partial esters of rosin, partially or completely hydrogenated rosin, polymerized Examples thereof include rosin, disproportionated rosin, dibasic acid-modified rosin which is a modified product of rosin and dibasic acid typified by maleic acid, and derivatives thereof. Furthermore, styrene / acrylic acid copolymer resin and the like can be mentioned.
These resins can be used alone or in combination of two or more.

  Examples of the material of the Japanese paper sheet 32 include thin paper or non-woven fabric. Here, the thin paper refers to mechanically-paste Japanese paper conforming to JIS P4500. Moreover, a nonwoven fabric means the sheet | seat which combined fibers, without weaving or knitting. Examples of the non-woven fabric include natural fibers such as cotton, hemp, wool fiber, palm fiber, and coco fiber; synthetic fibers such as polyamide, polyester, polypropylene, polyethylene, polyacrylonitrile, and polyurethane; glass fibers, carbon fibers, and metal fibers. And those composed of inorganic fibers.

In this embodiment, as Japanese paper sheet 32, the basis weight according to JIS P8124 is composed of tissue paper in the range of ^3g / ^{m 2 ~150g} / m 2 is preferred.
Further, Japanese paper sheet 32, the specific gravity of the apparent by JIS P8101 is composed of tissue paper in the range of 0.2g ^/ cm ³ ~1.3g ^/ cm 3 are preferred.

As the thin paper used in the present embodiment, paper containing fibers made from one or more plants selected from kouzo, mitsumata and ganpi (hereinafter referred to as “Japanese paper”) is preferable.
Specific examples of Japanese paper include, in addition to the above-mentioned thin paper, for example, sandpaper, honsho paper, Kyoto flower paper, Yoshino paper, Azabu paper, Mino paper, half paper, half-cut paper, Uchiyama paper, Hosokawa paper, Zao paper, Nishinouchi, Hodomura , Tosa paper, fountain paper, umbrella paper, Tonoko, Koshu tonoko, cloud paper, ink style, painting paper, hemp paper, fake paper, cloud dragon paper, straw paper, straw flower paper, Ogura paper, gold Japanese paper, Mura Usuzu, Examples include thin paper such as Shibuhiki Usu, strong paper, Wamp paper, straw shibu paper, and konjac paper. In addition, Japanese paper for shoji paper can also be mentioned.
In addition to the fiber which uses the plant as a raw material mentioned above, the Japanese paper may contain other fiber as needed. Examples of other fibers include synthetic fibers such as Manila hemp, wood pulp, straw pulp, waste paper, chemical pulp, and rayon.

In general, “Japanese paper”, in the narrowest sense, is made from the above-mentioned fibers extracted from plants and their old papers, and mixed with the sticky “Neri” extracted from the roots of troro-aoi and barley of Japanese radish, and is called Japan It is defined as handmade paper that incorporates unique techniques.
In the present embodiment, including the above-mentioned most narrowly-defined Japanese paper, paper made by machine paper using a paper machine (machine-made Japanese paper), paper that is longer than western paper and intertwined closely with each other, sticky and thin but tough paper ( Wide Japanese paper) can also be used.
As described above in detail, according to the present embodiment, it is possible to grind the substrate of the wafer having the substrate and the compound semiconductor layer formed on the substrate to a uniform thickness. In particular, when a substrate is warped due to a difference in lattice constant between the substrate and the compound semiconductor layer, such as a group III compound semiconductor light emitting device in which a group III nitride semiconductor is formed on a substrate such as sapphire. Even so, it is possible to uniformly grind the substrate to a predetermined thickness.

It is a figure explaining an example of the laminated semiconductor which is a semiconductor light emitting element used by this Embodiment. It is a figure explaining the grinding device of the wafer to which this embodiment is applied. It is a figure explaining the preferable method of attaching the wafer used by this Embodiment to a grinding device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Wafer, 10a, 11 ... Substrate, 12 ... Intermediate layer, 13 ... Underlayer, 14 ... N-type semiconductor layer, 15 ... Light emitting layer, 16 ... P-type semiconductor layer, 17 ... Compound semiconductor layer (Group III compound semiconductor layer) ), 20 ... pressure contact member, 22 ... elastic member, 23 ... pressure chamber, 31 ... carrier plate (fixing plate), 32 ... Japanese paper sheet, 33 ... wax for fixing, 34 ... grinding platen, 34a ... grinding surface, 50 ... Pressurized fluid supply means

Claims (7)

A wafer grinding apparatus having a substrate and a compound semiconductor layer formed on the substrate,
A grinding surface plate having a grinding surface for grinding a wafer substrate;
A fixing plate that is disposed to face the grinding surface of the grinding surface plate and fixes the wafer so that the substrate of the wafer faces the grinding surface;
A pressure contact member that deforms the shape of the fixed plate so as to follow the shape of the grinding surface of the grinding surface plate and applies pressure to the substrate of the wafer in contact with the ground surface through the fixed plate; A wafer grinding apparatus comprising:   2. The wafer grinding apparatus according to claim 1, wherein the pressure contact member includes a pressure chamber having a space closed by an elastic member provided so as to be in contact with the fixed plate.   3. The wafer grinding apparatus according to claim 2, further comprising pressurized fluid supply means for supplying pressurized fluid to the pressure chamber.   4. The wafer grinding apparatus according to claim 2, wherein the elastic member is made of silicone rubber. A method of manufacturing a semiconductor light emitting device having a substrate and a compound semiconductor layer formed on the substrate,
A bonding step of fixing the wafer to the fixing plate by bonding the compound semiconductor layer side of the wafer having the substrate and the compound semiconductor layer formed on the substrate to the fixing plate of the grinding apparatus;
The fixed plate to which the wafer is attached is disposed on the grinding surface plate so that the substrate of the wafer faces the grinding surface plate of the grinding apparatus, and the shape of the fixed plate is a grinding surface of the grinding surface plate. And a pressure-contacting step in which the substrate of the wafer is brought into contact with the grinding surface plate by applying pressure and deforming so as to follow the shape of
And a grinding step of grinding the substrate of the wafer brought into contact with the grinding platen.   6. The method of manufacturing a semiconductor light-emitting element according to claim 5, wherein a pressure for pressing the fixed plate is increased in accordance with a deformation amount of the grinding surface plate.   The method for manufacturing a semiconductor light emitting element according to claim 5, wherein the wafer is attached to the fixing plate via Japanese paper and a fixing agent.

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