Substrate, semiconductor device and polishing disk

Abstract

The utility model relates to the technical field of semiconductor manufacturing, in particular to a substrate, a semiconductor device and a polishing disc. The substrate is provided with a growth surface, and an epitaxial growth region is formed on at least part of the surface of the growth surface; the epitaxial growth region is provided with an edge region located at the edge of the epitaxial growth region, and the substrate located at the edge region has a thickness difference h1. Through the thickness difference design of different positions of the substrate, the uniformity of the epitaxial wavelength can be effectively improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of semiconductor, especially relates to a substrate, semiconductor device and polishing disc. BACKGROUND

[0002] At present, the traditional substrate processing is generally through the steps of wire cutting, grinding, annealing, chamfering, copper throwing and polishing to realize the planarization of the substrate surface for the subsequent growth of epitaxial structure. Generally, in order to the uniformity of subsequent yellow light and epitaxial wafer, the thickness difference and warping degree of the substrate need to be small enough, for example, the thickness difference of the substrate is required to be less than 6 microns and the warping degree is required to be less than 12 microns in general process.

[0003] In the process of the planarization of the substrate surface designed according to the prior art and the conventional growth of epitaxial structure, the substrate rotates at high speed in the graphite carrier disc, and the corresponding air flow exists windward side and leeward side, so that the symmetry uniformity of the epitaxial wavelength is prone to be poor. Therefore, how to improve the uniformity of the epitaxial wavelength is still a difficult problem to be solved by the technical personnel at present. SUMMARY

[0004] The utility model provides a kind of substrate, semiconductor device and polishing disc, can solve at least one problem in the background art to effectively improve the symmetry uniformity of epitaxial wavelength.

[0005] Firstly, the utility model provides a kind of substrate, and the substrate has growth surface, and at least part of surface of the growth surface is formed with epitaxial growth area;The epitaxial growth area has edge zone at the edge of the epitaxial growth area, and the substrate in the edge zone has thickness difference h1.

[0006] Secondly, the utility model further provides a kind of polishing disc for preparing the substrate as described in the first aspect, and the polishing disc has a contact surface for placing substrate, and the contact surface has height difference h2 at opposite ends.

[0007] Thirdly, the utility model further provides a kind of light emitting device, using the light emitting component as described in the above embodiment.

[0008] The substrate provided by the utility model can effectively improve the uniformity of epitaxial wavelength by the thickness difference design of different positions of the substrate, and further improve the performance of epitaxial structure when the substrate is applied to epitaxial growth.

[0009] Other features and advantages of the utility model will be described in the subsequent specification, and part of it becomes obvious from the specification, or is understood by implementing the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the description of the embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0011] Figure 1 is a schematic diagram of the epitaxial wavelength distribution on the conventional substrate;

[0012] Figure 2 is a schematic diagram of the epitaxial growth process of the conventional substrate on the base;

[0013] Figure 3 is a schematic diagram of the epitaxial growth process of the substrate of embodiment one on the base;

[0014] Figures 4-7 is a schematic diagram of the cross section of the substrate of each embodiment provided by the embodiment one of the present application;

[0015] Figure 8 is a schematic diagram of the top view structure of the substrate in Figure 7

[0016] Figure 9 is a schematic diagram of the epitaxial wavelength distribution on the substrate of the present embodiment;

[0017] Figure 10 is a schematic diagram of the polishing process of the polishing disc and the substrate in embodiment two.

[0018] Reference signs:

[0019] 1-substrate; S1-growth surface; 11-epitaxial growth area; 11a-edge area; 2-polishing disc; 21-contact surface. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. The technical features designed in different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0021] The present application provides a substrate, the substrate has a growth surface, at least part of the surface of the growth surface forms an epitaxial growth area; the epitaxial growth area has an edge area located at the edge of the epitaxial growth area, and the substrate located in the edge area has a thickness difference h1. Through the setting, the uniformity of the epitaxial wavelength on the substrate can be effectively improved. ​

[0022] In some embodiments, the width d of the edge region is 0.5% to 2% of the width D of the epitaxial growth region, so as to avoid the width d of the edge region being too small to achieve the purpose of uniform epitaxial wavelength.

[0023] In some embodiments, at least part of the edge region of the epitaxial growth region is a tilted surface. Preferably, the tilted surface has good flatness to ensure the quality of epitaxial layer growth.

[0024] In some embodiments, the epitaxial growth region has two opposite sides, and the minimum value of the substrate thickness of the edge region located at one side of the epitaxial growth region is greater than or equal to the maximum value of the substrate thickness of the edge region located at the opposite side of the epitaxial growth region. Through the above setting, the epitaxial wavelength can be better uniform.

[0025] In some embodiments, the angle α between the extension line from the highest point of the substrate thickness of the edge region to the lowest point of the substrate thickness of the edge region and the horizontal plane is 0.006° to 0.05°. By limiting the angle, the angle can be avoided to be too small to improve the epitaxial wavelength difference, and the angle can also be avoided to be too large to increase the difficulty of epitaxial growth and increase the dislocation density.

[0026] In some embodiments, the thickness difference h1 of the substrate located in the edge region is 15 to 30 microns. Through the limitation, the thickness difference can be avoided to be too small to improve the epitaxial wavelength difference, and the thickness difference can also be avoided to be too large to increase the difficulty of epitaxial growth and increase the dislocation density.

[0027] In some embodiments, the epitaxial growth region has two opposite sides, and the thickness of the substrate gradually decreases from one side of the epitaxial growth region to the opposite side. This setting not only achieves the effect of uniform epitaxial wavelength, but also ensures the quality of epitaxial growth.

[0028] In some embodiments, the size of the substrate is 4 to 12 inches, and the thickness of the substrate is 0.4 to 2 mm.

[0029] In some embodiments, the local thickness deviation LTV of the substrate is less than or equal to 3 microns.

[0030] The utility model also provides a kind of semiconductor device, including the substrate of any one embodiment as described above, also include epitaxial layer, the epitaxial layer is located on the epitaxial growth region of the substrate, to improve the symmetric uniformity of epitaxial luminescence wavelength of semiconductor device.

[0031] In some embodiments, the wavelength deviation of the epitaxial layer on the substrate in the edge region is less than or equal to 0.5 nm.

[0032] In some embodiments, the standard deviation of the light emitting wavelength of the epitaxial layer is between 0.5-1 nm.

[0033] The utility model also provides a polishing disc for preparing the substrate as the above embodiment, the polishing disc has a contact surface of placing the substrate, the contact surface has height difference h2 in opposite ends, the substrate prepared through the polishing disc can effectively realize the symmetry uniformity of the epitaxial light emitting wavelength.

[0034] In some embodiments, the contact surface of the polishing disc has an angle β with the horizontal plane, and the angle β is between 0.01°-0.1°.

[0035] In some embodiments, the height difference h2 of the contact surface is between 20-50 microns.

[0036] Next, the technical scheme of the utility model is described and explained in detail through various specific embodiments in combination with the different embodiments and the attached drawings.

[0037] Embodiment one

[0038] Please refer to Figures 4-7 , Figures 4-7 is the cross-sectional view of the substrate of each embodiment provided by the utility model embodiment one. In order to achieve at least one of the advantages or other advantages, the embodiment one discloses a substrate, the substrate 1 has growth surface S1, and at least part of the surface of the growth surface S1 is formed with epitaxial growth area 11. In the embodiment, the substrate 1 can adopt materials with low thermal conductivity, such as sapphire, silicon, silicon carbide and other materials. Of course, the material of the substrate 1 also considers the material that can match the GaN lattice, so as to be effectively applied to GaN epitaxial growth. As an example, the embodiment preferably the size of the substrate 1 is between 4-12 inches, and the thickness of the substrate 1 is between 0.4-2 mm.

[0039] Wherein, the growth surface S1 of the substrate 1 has epitaxial growth area 11, and the epitaxial growth area 11 refers to the area for growing epitaxial layer. Generally, the growth surface S1 of the substrate 1 is consistent with the epitaxial growth area 11, and the epitaxial layer grows to completely cover the entire growth surface S1 of the substrate 1, for example Figures 5-7 Of course, the embodiment does not exclude that the upper epitaxial growth area 11 is in the projection range of the growth surface S1 of the substrate 1, for example Figure 4 That is, the epitaxial layer grows to only cover part of the growth surface S1 of the substrate 1. It can be designed according to actual needs.

[0040] In a conventional substrate, it is generally required that the epitaxial growth region has a very flat surface to ensure the uniformity of subsequent photolithography and epitaxial wafer. However, in a conventional epitaxial process using a substrate with a flat surface, the inventors have found that the epitaxial wavelength exhibits a typical asymmetric distribution. As shown in Figure 1 FIG. 1 shows the distribution of epitaxial wavelength on a substrate in a conventional design, where different color depths represent the difference in epitaxial wavelength, the left green distribution area in the figure represents a relatively shorter epitaxial wavelength, and the right red area represents a relatively longer epitaxial wavelength. The distribution of the left and right areas is not symmetrical. As can be seen, the conventional substrate and the conventional epitaxial growth method have the problem of poor uniformity of epitaxial wavelength.

[0041] To effectively solve the above problems, the substrate is improved in this embodiment, and the uniformity of epitaxial wavelength is compensated by differential adjustment of the thickness of the substrate. In specific implementation, the epitaxial growth region 11 has an edge region 11a located at the edge of the epitaxial growth region 11, and the substrate 1 located at the edge region 11a has a thickness difference h1. By designing the edge of the epitaxial growth region 11 to have a thickness difference h1, the temperature difference of different positions of the edge region 11a of the substrate 1 is ensured to affect the epitaxial wavelength.

[0042] In detail, as shown in Figure 2 , Figure 3 , in the epitaxial growth process, the substrate 1 is generally placed on a pedestal, and the high-speed rotation of the pedestal and the horizontal blowing of the reaction gas from one side of the reaction chamber cause the material to be uniformly deposited on the growth surface S1 of the substrate 1. Since the temperature of the pedestal is higher than that of the substrate 1, and the pedestal is easy to generate centrifugal force in high-speed rotation, the temperature of the substrate 1 is higher on the windward side where the reaction gas is first blown, and the temperature is lower on the leeward side where the reaction gas is blown later. However, the conventional substrate and the conventional epitaxial growth method shown in Figure 2 have the problem of poor uniformity of epitaxial wavelength. Therefore, as shown in Figure 3 , the edge region 11a of the substrate 1 is provided with a thickness difference h1, and the heat conduction of different positions is locally adjusted by the thickness difference. In the epitaxial growth process, the position of the edge region 11a with a thicker thickness of the substrate 1 can be placed on the windward side where the reaction gas is first blown, so as to reduce the heat conduction of the position of the edge region 11a with a thicker thickness, thereby reducing the growth temperature of the position and increasing the epitaxial wavelength at the position, effectively ensuring the consistency of the epitaxial wavelength of the position and other positions of the epitaxial growth region 11. Similarly, in the epitaxial growth process, the position of the edge region 11a with a thinner thickness of the substrate 1 can be placed on the leeward side where the reaction gas is blown last, so as to increase the heat conduction of the position of the edge region 11a with a thinner thickness, thereby increasing the growth temperature of the position and reducing the epitaxial wavelength at the position, effectively ensuring the consistency of the epitaxial wavelength of the position and other positions of the epitaxial growth region 11.

[0043] Based on the above, in the embodiment, the edge area 11a of the epitaxial growth area 11 on the substrate 1 is provided with a thickness difference h1, which can effectively avoid the asymmetry of the epitaxial wavelength in the subsequent epitaxial growth process, and improve the quality and performance of the epitaxial layer.

[0044] Further, as shown in Figure 7 , the embodiment also defines the edge area 11a, which refers to the area range where the edge of the epitaxial growth area 11 is offset inward by a width d. In this area range, the thickness of some positions is relatively thick, and the thickness of some positions is relatively thin. The width d of the edge area 11a is 0.5% to 2% of the width D of the epitaxial growth area 11. By limiting the width d of the edge area 11a, it can avoid the situation that the width is too small to play a role in uniform epitaxial wavelength. Of course, the epitaxial growth area 11 also includes a central area, and the edge area 11a surrounds the central area. The substrate 1 at each position in the central area can have a thickness difference, for example Figure 6 , the central area and the edge area 11a have different thickness difference slopes, for example Figure 7 , the central area and the edge area 11a have the same thickness difference slope; or can not have a thickness difference, for example Figure 5 , which is specifically adjusted according to the actual non-uniformity of the epitaxial wavelength. The embodiment is not limited in this regard.

[0045] Preferably, as shown in Figure 7 , the thickness difference h1 of the substrate 1 located in the edge area 11a is 15 to 30 microns. By limiting the thickness difference h1 of the substrate 1 located in the edge area 11a, it can avoid the situation that the thickness difference is too small to improve the epitaxial wavelength difference, and also can avoid the situation that the thickness difference is too large to increase the epitaxial crystal difficulty and increase the dislocation density.

[0046] In an optional embodiment, as shown in Figure 4 , Figure 5 , at least part of the edge area 11a of the epitaxial growth area 11 is an inclined surface. Specifically, when the epitaxial wavelength has poor uniformity, the variation of the area with shorter or longer wavelength is generally continuous and gradual. Therefore, the edge area 11a is provided as an inclined surface in the embodiment, and the inclined surface is also continuous and gradual, which can better adapt to the continuous and gradual compensation of the epitaxial wavelength, and better ensure the symmetry and uniformity of the epitaxial wavelength.

[0047] Further, as shown in Figure 7The angle α between the extension line of the substrate 1 at its thickest point in the edge region 11a and the extension line at its thinnest point in the edge region 11a and the horizontal plane is between 0.006° and 0.05°. By limiting the angle of the thickness deviation in the edge region 11a, it is possible to avoid the problem that the difference in epitaxial wavelength symmetry uniformity cannot be improved if the angle is too small, while it is also possible to avoid the problem that the epitaxial epitaxialization difficulty and dislocation density will increase if the angle is too large.

[0048] In another optional embodiment, the epitaxial growth region 11 has opposite sides, and the minimum thickness of the substrate 1 of the edge region 11a on one side of the epitaxial growth region 11 is greater than or equal to the maximum thickness of the substrate 1 of the edge region 11a on the opposite side of the epitaxial growth region 11. This arrangement effectively ensures that during epitaxial growth, the thickness of the edge region 11a on the windward side is greater than that on the leeward side, guaranteeing that the edge region 11a on the windward side has lower thermal conductivity and the edge region 11a on the leeward side has higher thermal conductivity. This, in turn, uniformizes the temperature difference between the windward and leeward sides, better achieving symmetrical uniformity of the epitaxial wavelength.

[0049] Considering the epitaxial growth effect, such as Figure 7 As shown, in this embodiment, the thickness of the substrate 1 in the epitaxial growth region 11 gradually decreases from one side to the opposite side, and the thickness decreases linearly, so that the surface of the epitaxial growth region 11 is a uniform and continuous inclined plane. The uniform and continuous inclined plane can not only achieve the effect of uniform epitaxial wavelength, but also ensure the quality of epitaxial growth.

[0050] Preferably, when the substrate 1 is used to grow an epitaxial layer, the standard deviation of the emission wavelength std of the epitaxial layer on the substrate 1 is between 0.5 and 1 nm. Specifically, by adjusting the thickness difference of the epitaxial growth region 11 of the substrate 1, the standard deviation of the emission wavelength std of the epitaxial layer on the substrate 1 can be reduced to 0.5 to 1 nm, thereby effectively ensuring the symmetrical uniformity of the emission wavelength of the epitaxial layer.

[0051] In the design process of the thickness difference of substrate 1, in order to avoid difficulties in epitaxial epitaxy and increased dislocation density due to a large thickness difference, this embodiment preferably has a local thickness deviation (LTV) of substrate 1 that is less than or equal to 3 micrometers. Specifically, regardless of how the thickness difference of substrate 1 changes, this embodiment controls the local thickness deviation of substrate 1 to not exceed 3 micrometers to avoid the impact of excessive thickness deviation on epitaxial growth. Here, the local thickness deviation (LTV) of substrate 1 refers to the thickness deviation value of a local region of substrate 1, where the local region can be defined as an area within a 15*15mm range.

[0052] To effectively illustrate the effect of the substrate 1 designed in the embodiment, the epitaxial wavelength on the substrate 1 with thickness difference is tested in the embodiment, and a distribution diagram of the epitaxial wavelength on the substrate 1 can be obtained as shown in the following table. Figure 10 Figure 1 Figure 10 Only the thickness of the substrate 1 is different, and other conditions are the same. It can be seen that the epitaxial wavelength of the substrate 1 with thickness difference in the embodiment is relatively symmetrical and uniformly distributed.

[0053] Embodiment Two

[0054] The second embodiment provides a semiconductor device, which comprises the substrate 1 as described in the above first embodiment, and further comprises an epitaxial layer grown on the epitaxial growth region 11 of the growth surface S1 of the substrate 1, so as to effectively improve the symmetry and uniformity of the light-emitting wavelength. The semiconductor device can be a light-emitting device with an epitaxial layer, such as a light-emitting diode, a semiconductor laser, etc.

[0055] It should be noted that the substrate 1 applied in the semiconductor device in the embodiment is used as a growth substrate 1 for growing an epitaxial layer, and the skilled person in the art can also apply the substrate 1 mentioned in the above first embodiment to any temporary growth substrate which needs to be epitaxially grown, which also falls within the protection scope of the present application.

[0056] In an optional embodiment, the wavelength deviation of the epitaxial layer on the substrate 1 located in the edge region 11a is less than or equal to 0.5 nm, so as to ensure that the light-emitting wavelength of the epitaxial layer of the edge region 11a is relatively consistent. Specifically, the wavelength deviation of the epitaxial layer can be less than or equal to 0.5 nm by adjusting the thickness difference of the substrate 1.

[0057] In another optional embodiment, the standard deviation of the light-emitting wavelength of the epitaxial layer is between 0.5 nm and 1 nm. Specifically, the standard deviation of the light-emitting wavelength of the epitaxial layer can be adjusted according to the thickness difference of the epitaxial growth region 11 of the substrate 1, so as to reduce the standard deviation of the light-emitting wavelength of the epitaxial layer to 0.5 nm to 1 nm, thereby effectively ensuring the symmetry of the light-emitting wavelength of the epitaxial layer and improving the optical efficiency and the uniformity of the light-emitting brightness of the semiconductor device.

[0058] Embodiment Three

[0059] Please refer to Figure 10 , the second embodiment provides a polishing disc 2 for preparing the substrate 1 as described in the above first embodiment, the polishing disc 2 has a contact surface 21 for placing the substrate 1, and the contact surface 21 has a height difference h2 at opposite ends.

[0060] ​​In a specific application, the contact surface 21 of the polishing disc 2 should be in contact with the growth surface S1 of the substrate 1, and the growth surface S1 of the substrate 1 is polished by the contact surface 21 of the polishing disc 2, so that the growth surface S1 of the substrate 1 has a thickness difference adapted to the contact surface 21 of the polishing disc 2. Specifically, when the growth surface S1 is polished by the height difference h2 of the contact surface 21, different height differences will cause the growth surface S1 to have different contact pressures, and then the growth surface S1 will have different removal rates during polishing, so that the substrate 1 has a thickness difference, so that the prepared substrate 1 can effectively realize the symmetric uniformity of the epitaxial light emitting wavelength.

[0061] Preferably, the height difference h2 of the contact surface 21 is between 20-50 microns. The range of the height difference h2 of the contact surface 21 is greater than the range of the thickness difference h1 of the edge area 11a of the substrate 1. The embodiment preferably h2>h1. Specifically, the area of the growth surface S1 of the substrate 1 is smaller than the area of the contact surface 21 of the polishing disc 2, so that the growth surface S1 of the substrate 1 can be polished sufficiently. Therefore, the height difference h2 of the polishing disc 2 is relatively greater than the thickness difference h1 of the substrate 1.

[0062] Further, the contact surface 21 of the polishing disc 2 has an angle β with the horizontal plane, and the range of the angle β is 0.01°-0.1°. Specifically, the range of the angle β of the contact surface 21 of the polishing disc 2 with the horizontal plane is greater than the range of the angle α of the substrate 1, and the embodiment preferably β>α. This setting is because during polishing, the polishing disc 2 is prone to expansion as the temperature rises, and the intermediate area will be appropriately raised, so the angle range needs to be slightly larger, so as to compensate for the influence of temperature on the polishing of the surface of the substrate 1 during polishing.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A substrate, characterized by: The substrate has a growth surface, at least part of the growth surface forms an epitaxial growth region; the epitaxial growth region has an edge region at the edge of the epitaxial growth region, the substrate at the edge region has a thickness difference h1.

2. The substrate of claim 1, wherein: The width d of the edge region is 0.5% to 2% of the width D of the epitaxial growth region.

3. The substrate of claim 1, wherein: At least part of the edge region of the epitaxial growth region is an inclined surface.

4. The substrate of claim 1, wherein: The epitaxial growth region has opposite sides, the minimum value of the thickness of the substrate at the edge region of one side of the epitaxial growth region is greater than or equal to the maximum value of the thickness of the substrate at the edge region of the opposite side of the epitaxial growth region.

5. The substrate of claim 1, wherein: The angle α between the extension line of the highest point of the thickness of the substrate at the edge region and the lowest point of the thickness of the substrate at the edge region and the horizontal plane is 0.006° to 0.05°.

6. The substrate of claim 1, wherein: The thickness difference h1 of the substrate at the edge region is 15 to 30 microns.

7. The substrate of claim 1, wherein: The epitaxial growth region has opposite sides, the thickness of the substrate at the epitaxial growth region gradually decreases from one side to the opposite side.

8. The substrate of claim 1, wherein: The size of the substrate is 4 to 12 inches, and the thickness of the substrate is 0.4 to 2 mm.

9. The substrate of claim 1, wherein: The local thickness deviation LTV of the substrate is less than or equal to 3 microns.

10. A semiconductor device, characterized by: The substrate according to any one of claims 1 to 9, further comprising an epitaxial layer on the epitaxial growth region of the substrate.

11. The semiconductor device of claim 10, wherein: The wavelength deviation of the epitaxial layer on the substrate at the edge region is less than or equal to 0.5 nm.

12. The semiconductor device of claim 10, wherein: The standard deviation of the emission wavelength of the epitaxial layer is 0.5 to 1 nm.

13. A polishing disk for use in the manufacture of the substrate of claim 1, wherein: The polishing disc has a contact surface for placing a substrate, the contact surface has a height difference h2 at opposite ends.

14. The polishing disk of claim 13, wherein: The contact surface of the polishing disc has an angle β with the horizontal plane, and the angle β is 0.01° to 0.1°.

15. The polishing disk of claim 13, wherein: The height difference h2 of the contact surface is 20 to 50 microns.

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