CN116169220A - Substrate and processing method thereof, light-emitting diode and manufacturing method thereof - Google Patents
Substrate and processing method thereof, light-emitting diode and manufacturing method thereof Download PDFInfo
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
- H10H20/01—Manufacture or treatment
- H10H20/011—Manufacture or treatment of bodies, e.g. forming semiconductor layers
- H10H20/013—Manufacture or treatment of bodies, e.g. forming semiconductor layers having light-emitting regions comprising only Group III-V materials
- H10H20/0133—Manufacture or treatment of bodies, e.g. forming semiconductor layers having light-emitting regions comprising only Group III-V materials with a substrate not being Group III-V materials
- H10H20/01335—Manufacture or treatment of bodies, e.g. forming semiconductor layers having light-emitting regions comprising only Group III-V materials with a substrate not being Group III-V materials the light-emitting regions comprising nitride materials
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- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
- H01L21/3046—Mechanical treatment, e.g. grinding, polishing, cutting using blasting, e.g. sand-blasting
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- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
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- H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
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Abstract
The invention aims to provide a processing method of an asymmetric surface type substrate, a light emitting diode and a manufacturing method thereof. Firstly, determining an asymmetric surface type presented by a substrate, determining the asymmetric orientation of the asymmetric surface type, carrying out local sand blasting on the substrate in the asymmetric orientation, recessing the local area, compensating the stress distribution of the substrate, and converging the substrate from the asymmetric surface type to the symmetric surface type. A substrate exhibiting a symmetrical plane shape, such as a bowl shape, is advantageous for optimizing the wavelength uniformity of the subsequently formed epitaxial layer.
Description
Technical Field
The present invention relates to the field of semiconductor manufacturing technology, and in particular, to a substrate, a processing method thereof, a light emitting diode, and a manufacturing method thereof.
Background
In the fabrication of semiconductor devices, it is often necessary to perform epitaxial layer growth with the aid of a growth substrate for which substrate warpage/bending is the most important factor affecting epitaxial uniformity. For example, a sapphire substrate, which is typically a growth substrate for a GaN epitaxial layer, may cause uneven stress to the substrate during the machining of the sapphire substrate, thereby twisting the substrate; for example: in the multi-wire cutting process, as the sapphire is harder, the diamond wire is subjected to larger cutting resistance, jitter and deformation occur, and the positions of two lateral lines of the substrate are asymmetric, so that the substrate is stressed unevenly and is distorted; during the polishing process, the abrasive particles gradually decrease over time, while the pressure of the particles of different sizes against the substrate is different, resulting in different residual stresses of the substrate; after single-sided polishing, the roughness of the two sides of the final substrate is different, which results in different stress conditions on the two sides of the substrate, and distortion is further deteriorated. The bending/twisting of the substrate causes the substrate to exhibit an asymmetric planar shape, which may result in a reduced convergence of the wavelength of the subsequently formed epitaxial layer. The uniformity of the wavelength of the epitaxial layer directly affects the yield of the later devices.
In the prior art, the warpage shape or warpage amount of a substrate is generally controlled by controlling a flat sheet processing process of the substrate, such as processes of crystal growth, cutting, grinding, annealing, copper polishing, and polishing. However, such a method does not allow the substrate to be completely converged into a symmetrical plane type. Therefore, it is necessary to provide a method capable of converging the substrate effectively into a symmetrical plane shape.
Disclosure of Invention
In view of the above-described drawbacks of the prior art, an object of the present invention is to provide a substrate and a processing method thereof, a light emitting diode and a manufacturing method thereof. Firstly, determining an asymmetric surface type presented by a substrate, determining the asymmetric orientation of the asymmetric surface type, carrying out local sand blasting on the substrate in the asymmetric orientation, recessing the local area, compensating the stress distribution of the substrate, and converging the substrate from the asymmetric surface type to the symmetric surface type. A substrate exhibiting a symmetrical plane shape, such as a bowl shape, is advantageous for wavelength uniformity of the subsequently formed epitaxial layer.
To achieve the above and other related objects, one embodiment of the present invention provides a method for processing a substrate: the method comprises the following steps:
providing a substrate and determining an asymmetric profile exhibited by the substrate, the substrate having a first surface and a second surface;
determining an asymmetric orientation of the asymmetric profile and measuring a degree of curvature of the substrate in the asymmetric orientation;
in the asymmetric orientation, locally blasting the substrate to cause the substrate to converge from an asymmetric surface shape to a symmetric surface shape.
Optionally, determining an asymmetric orientation of the asymmetric plane type and measuring a curvature of the substrate in the asymmetric orientation, further comprises the steps of:
determining a first orientation and a second orientation of the asymmetric profile, the first orientation and the second orientation being intersecting asymmetric orientations;
measuring a first curvature bow1 of the substrate in the first orientation along the first surface;
measuring a second bow bow2 of the substrate in the second orientation along the first surface;
defining the substrate to bend in an asymmetric orientation towards the first surface, the bending being negative;
the substrate is bent towards the second surface in an asymmetric direction, and the bending degree is a positive value;
the value of the first curvature bow1 is negative and the value of the first curvature bow is less than the value of the second curvature bow2, defining Δ bow = bow1-bow2.
Optionally, the roughness value of the first surface of the substrate is smaller than the roughness value of the second surface.
Optionally, the surface of the substrate subjected to localized blasting is a second surface.
Optionally, the asymmetric surface shape presented by the substrate includes any one of the following:
concentric ellipses, the substrate being curved in the same direction but different in curvature in the asymmetric direction;
a penetration type substrate which is curved in one direction and is not curved in the other direction asymmetric to the one direction;
saddle-shaped, the substrate being curved in opposite directions in an asymmetric direction.
Optionally, the asymmetric surface type of the substrate is determined according to the measurement result after measurement, and the measuring machine is a flatness measuring instrument.
Optionally, the substrate is also subjected to cutting, grinding, chamfering and annealing treatments prior to measurement.
Optionally, the substrate is also subjected to copper polishing and polishing after measurement, sandblasting.
Optionally, the substrate is locally sandblasted, and the specific steps include: the second curvature bow2 is adjusted to the value of the first curvature bow1 to cause the substrate to converge from an asymmetric profile to a symmetric profile.
Optionally, locally sandblasting the substrate, wherein the sandblasted area is bowknot-shaped, and the specific shape is as follows: and two opposite sectors taking the intersection point of the first orientation and the second orientation of the substrate as a center of a circle and taking the second orientation of the substrate as a symmetry axis.
Optionally, the radius r of the sector is the same as the radius of the substrate, and the radius r of the sector is greater than or equal to 1 inch.
Optionally, the included angle θ of the fan is 30 ° to 120 °.
Optionally, the substrate is locally sandblasted, wherein the sand species comprises diamond, silicon carbide, boron carbide, aluminum oxide or silicon oxide.
Optionally, locally sandblasting the substrate, wherein the pressure p= -k is delta bow, and the value range of k is 0.1-10 Mpa/um.
Optionally, the pressure p of the sand blasting is between 0.01 and 100MPa.
Optionally, locally sand blasting the substrate, wherein the mesh number of the sand is 50-10000 meshes.
Another embodiment of the present invention provides a method for manufacturing a light emitting diode, including the steps of:
providing a substrate and determining an asymmetric profile exhibited by the substrate, the substrate having a first surface and a second surface;
determining an asymmetric orientation of the asymmetric profile and measuring a degree of curvature of the substrate in the asymmetric orientation;
locally blasting the substrate in the asymmetric direction to enable the substrate to be converged from an asymmetric surface shape to a symmetric surface shape;
a light emitting structure is formed over the substrate converged to a symmetrical plane.
Optionally, forming the light emitting structure over the substrate includes the steps of:
forming a first semiconductor layer over the substrate;
forming multiple quantum wells over the first semiconductor layer;
a second semiconductor layer of opposite conductivity to the first semiconductor layer is formed over the multiple quantum well.
Another embodiment of the present invention provides a substrate for epitaxial growth, the substrate having a first surface and a second surface, the substrate being manufactured by the substrate processing method described above, the substrate being converged from an asymmetric surface shape to a symmetric surface shape after being locally sandblasted.
Still another embodiment of the present invention provides a light emitting diode, including a substrate and a light emitting structure formed over the substrate, wherein the substrate is a substrate for epitaxial growth provided by the present invention.
As described above, the substrate and the processing method thereof, the light emitting diode and the manufacturing method thereof provided by the invention have at least the following beneficial technical effects:
in the method, firstly, the asymmetric surface type of the substrate is determined, the asymmetric orientation of the asymmetric surface type is determined, the substrate is subjected to local sand blasting treatment in the asymmetric orientation, uniform stress can be generated on the back surface (the surface with larger roughness) of the substrate by sand blasting, the size of the stress can be controlled by adjusting sand blasting parameters, a bowknot-shaped local sand blasting area is designed aiming at the characteristics of the annealed asymmetric surface type substrate, the warping of a substrate protruding area or a flat area is concave, the whole substrate presents the same concave degree in each radial direction, the asymmetric surface type is adjusted to be the symmetric surface type, and the substrate presents the symmetric surface type, such as a bowl-shaped (or concentric circle-shaped) substrate. And growing the epitaxial layer on the substrate converged to the symmetrical plane type is beneficial to reducing the wavelength dispersion of the epitaxial layer, namely, the wavelength of the epitaxial layer is converged, the convergence of the wavelength of the epitaxial layer is improved to directly influence the yield of subsequent devices, and the device yield is greatly improved.
The substrate for epitaxy and the semiconductor device of the invention can be processed by the method, so the substrate for epitaxy and the semiconductor device have the beneficial effects.
Drawings
FIG. 1 shows a schematic diagram of the bending profile of a saddle-shaped substrate distorted due to non-uniformity of stress distribution as measured by a flatness measuring instrument.
Fig. 2 is a schematic view showing the bending distribution of a penetration type substrate distorted due to uneven stress distribution, which is tested by a flatness measuring instrument.
Fig. 3 shows a schematic diagram of the bending distribution of a concentric oval substrate distorted due to uneven stress distribution, as measured by a flatness measuring instrument.
Fig. 4 shows a schematic diagram of the bending distribution of a planar substrate with uniform stress distribution as measured by a flatness measuring instrument.
Fig. 5 is a flowchart showing a method for manufacturing an epitaxial substrate according to an embodiment of the present invention.
Fig. 6 shows a schematic diagram of a determined asymmetric orientation for a saddle-type substrate.
Fig. 7 shows a schematic view of the shape of the blast area determined for a saddle-type substrate.
Fig. 8 shows a schematic view of a determined asymmetric orientation for a penetrating substrate.
Fig. 9 shows a schematic view of the shape of the blast area determined for a penetrating substrate.
Fig. 10 shows a schematic diagram of a determined asymmetric orientation for a concentric elliptical substrate.
Fig. 11 shows a schematic view of the shape of the blast area determined for a concentric oval substrate.
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
It should be noted that, the illustrations provided in the present embodiment only illustrate the basic concept of the present invention by way of illustration, but only the components related to the present invention are shown in the illustrations, rather than being drawn according to the number, shape and size of the components in actual implementation, and the form, number, positional relationship and proportion of each component in actual implementation may be changed at will on the premise of implementing the present technical solution, and the layout of the components may be more complex. Thus, variations in the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, the exemplary embodiments should not be considered limited to the particular shapes of the regions illustrated in the figures, but may also include deviations in shapes that result, for example, from manufacturing processes. In the drawings, the length and size of certain layers and regions may be exaggerated for clarity. Like reference numerals in the drawings denote like parts. It will also be understood that when a layer is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present.
The preparation of the substrate is an important link in the manufacturing process of the semiconductor device, and the yield of the substrate directly influences the performance of the device. The substrate is usually a very thin sheet, and during the machining process of the substrate, the substrate inevitably has defects such as bending, warping and the like due to uneven stress distribution, and the bending, warping or warping of the substrate directly affects the quality of subsequent epitaxial film formation.
The substrate stress maldistribution causes the substrate to bend, warp or twist in different directions and the degree and/or direction of bending in different directions is different, which causes the substrate to assume an asymmetric planar shape. If the substrate stress distribution is relatively uniform, the substrate tends to have the same bending direction and degree in each radial direction, and the substrate exhibits a symmetrical plane shape. The symmetrical plane type substrate has better bending convergence, and is favorable for wavelength convergence of an epitaxial film-forming layer when the substrate is used for epitaxial film-forming.
As shown in fig. 1 to 3, taking a sapphire substrate as an example, the substrate has a first surface and a second surface opposite to the first surface, two vertical directions in which the substrate extends radially are defined as a transverse direction and a longitudinal direction, and the substrate is tested for curvature distribution from one surface of the substrate by using a flatness measuring instrument, and the sapphire substrate generally has four different surface shapes. As shown in fig. 1, if the peripheral region of the substrate is curved toward the first surface in the lateral direction and the peripheral region of the substrate is curved toward the second surface in the longitudinal direction, the substrate assumes a saddle-like shape, and thus such a substrate face shape is generally referred to as a saddle shape; as shown in fig. 2, if a part of the peripheral region of the substrate is curved toward the same surface (i.e., the first surface or the second surface) in the lateral direction and a part of the peripheral region of the substrate is flat and warp-free in the longitudinal direction, a substrate surface shape exhibiting such a curved type is generally referred to as a penetration type; as shown in fig. 3, if the peripheral region of the substrate is curved toward the same surface (i.e., the first surface or the second surface) in both the longitudinal direction and the lateral direction, and the degree of curvature in the lateral direction is greater than the degree of curvature in the longitudinal direction at the same distance from the center of the substrate, the substrate surface shape assumes a concentric ellipse shape.
The substrate surface patterns shown in fig. 1 to 3 are generally referred to as asymmetric surface patterns because the substrate exhibits different bending directions and/or different bending degrees in different radial directions due to uneven stress distribution, and thus the substrate which should be completely symmetrical in each radial direction of the substrate exhibits asymmetric characteristics in some radial directions.
The substrate shown in fig. 4 has a relatively uniform stress distribution, and the substrate is bent to almost the same degree at each radial position of the peripheral region at the same distance from the center of the substrate, and is bent toward the same surface (i.e., the first surface or the second surface), and the substrate is bent to have a concentric circular or bowl-shaped surface. The concentric circular substrate may be referred to as a symmetrical plane because the stress distribution is relatively uniform, the bending direction of the peripheral region in each radial direction is the same and the degree of bending tends to be the same, and the substrate remains substantially symmetrical in each radial direction. The substrate with concentric circular surface has better bending convergence, and is favorable for wavelength convergence of an epitaxial film-forming layer when the substrate is used for epitaxial film-forming.
With respect to the above-described characteristics of substrate bending, the present embodiment aims to provide a substrate processing method capable of improving substrate surface type convergence.
As shown in fig. 5, in an embodiment of the present invention, the method for manufacturing an epitaxial substrate of the present invention includes the steps of:
s01: providing a substrate and determining an asymmetric profile exhibited by the substrate, the substrate having a first surface and a second surface;
s02: determining an asymmetric orientation of the asymmetric profile and measuring a degree of curvature of the substrate in the asymmetric orientation;
s03: in the asymmetric orientation, locally blasting the substrate to cause the substrate to converge from an asymmetric surface shape to a symmetric surface shape.
In this embodiment, the substrate may be any substrate used in semiconductor manufacturing, and may be, for example, a substrate suitable for epitaxial layer growth. In an alternative embodiment, the substrate is a substrate, such as a sapphire substrate, that can be adjusted in substrate warpage by grit blasting to improve stress distribution. The sapphire substrate has a thickness of about 50 μm to 20mm and may have a diameter of 2 inches to 18 inches.
In this embodiment, taking a sapphire substrate as an example, the substrate has a first surface and a second surface, typically, two surfaces of the sapphire have different roughness, the roughness value of the first surface is smaller than that of the second surface, the roughness value of the first surface is smaller than 0.5nm, the smaller roughness makes the sapphire present a smooth surface so as to facilitate the bonding of chemical bonds of an epitaxial layer material and chemical bonds of the sapphire during epitaxial growth, thereby growing a flat epitaxial layer, when the roughness of the first surface is greater than 0.5nm, a larger thermal expansion coefficient difference exists between the epitaxial layer material and the sapphire substrate, and obvious crystal boundaries appear in the epitaxial layer, resulting in defects; the roughness of the second surface is 0.9-1.2 mu m, so that the brightness of the epitaxial layer in the growth process can be conveniently adjusted. Epitaxy is a heterogeneous crystal growth process, and because of the large difference of thermal expansion coefficients of the sapphire substrate and the epitaxial layer material, the epitaxial layer can present a convex shape with a higher center and a lower peripheral area, and the convex shape is matched with the convex shape, the first surface of the sapphire substrate presents a concave shape with a lower center point and a higher peripheral area at least in 1 asymmetric orientation.
In this embodiment, the bow distribution of the substrate is tested from the first surface of the sapphire substrate using a flatness measuring instrument, thereby determining the surface shape exhibited by the substrate.
In an alternative embodiment of the present embodiment, as shown in fig. 6, the peripheral region of the substrate is curved toward the first surface in two different radial directions of the surface of the substrate, but the degree of curvature of the substrate is different in the two different radial directions at the same distance from the center of the substrate, and at this time, the surface shape of the substrate is a concentric oval shape and an asymmetric surface shape.
After the topography of the substrate is determined, two asymmetric orientations of the substrate exhibiting asymmetric curvature are determined. For the concentric oval-shaped substrate shown in fig. 6, the first orientation 101 and the second orientation 102 of the oval-shaped substrate are determined, and the substrate is curved toward the first surface in both the first orientation 101 and the second orientation 102, but the degree of curvature of the substrate is different at the same distance from the center of the substrate.
After determining the above-mentioned asymmetric orientation of the substrate, the first bow bow1 of the substrate in the first orientation 101 and the second bow bow2 of the substrate in the second orientation 102 are measured, in this embodiment the first bow bow1 and the second bow bow are both negative and the value of bow1 is smaller than the value of bow, and the difference between the first bow bow1 and the second bow bow2 is obtained according to Δ bow = bow1-bow2.
The second surface of the sapphire substrate is sandblasted, the shape of the sandblasted area is a bowknot shape as shown in fig. 7, the intersection point of the first orientation 101 and the second orientation 102 of the sapphire substrate is used as the center of a circle, the second orientation 102 of the sapphire substrate is used as a symmetrical axis, and the two opposite sectors are arranged, wherein the radius of each sector is the same as that of the sapphire substrate and is greater than or equal to 1 inch, in the current sapphire substrate processing industry, the radius of the substrate is greater than 1 inch, the sapphire stress distribution smaller than 1 inch is relatively uniform, and most of the surface shapes are symmetrical surface shapes without adjustment.
The larger the value of Δ bow, the greater the difference between the first curvature bow and the second curvature bow2, the greater the degree of substrate stress non-uniformity, and the larger the area of the blast region fan should be, and therefore the larger the angle θ of the blast region fan should be. In this embodiment, the first curvature bow1 and the second curvature bow are both negative, and the angle θ of the fan-shaped sandblasted area is determined according to the difference between the first curvature bow1 and the second curvature bow2, where the angle θ of the fan-shaped sandblasted area is between 30 ° and 120 °.
The sand species include diamond, silicon carbide, boron carbide, aluminum oxide, or silicon oxide. In this embodiment, the material of the substrate is blue
The hardness of the precious stone and the sand should be greater than that of the sapphire, and diamond, silicon carbide or boron carbide can be selected.
The larger the value of Δ bow, the greater the difference between the first and second curvatures bow, bow, and the greater the degree of substrate stress non-uniformity, the greater the need for a greater sandblasting pressure to adjust the second curvature bow2. In this embodiment, the pressure p= -k Δ bow of the sand blasting is 0.1-10 Mpa/um, when the hardness of the sand is large, a smaller k value can be selected, and when the hardness of the sand is small, a larger k value can be selected.
In this embodiment, the pressure p of the sandblasting is between 0.01mpa and 100mpa, the pressure p of the sandblasting is proportional to the k value, the greater the k value is, the greater the pressure p of the sandblasting is, and the smaller the k value is, the pressure p of the sandblasting is reduced.
When the mesh number of the sand is more than 10000 meshes, the roughness of the second surface of the sapphire substrate can be reduced; when the mesh number of the sand is less than 50 mesh, the roughness of the second surface of the sapphire substrate becomes large. In order to ensure that the roughness of the second surface of the sapphire substrate is 0.9 μm to 1.2 μm, the mesh number of the sand in the embodiment is 50 mesh to 10000 mesh.
In this embodiment, the second surface of the substrate is sandblasted by impacting the second surface of the substrate with high-speed and high-pressure sand to generate a stress difference with the first surface, and the second curvature bow2 which is originally different from the first curvature bow1 is adjusted to the level of the first curvature bow1, so that the substrate has almost the same bending degree in each radial direction towards the first surface, and the surface shape of the substrate is a symmetrical surface shape like a circle or bowl.
In another alternative of this embodiment, as shown in fig. 8, a portion of the peripheral region of the substrate is curved toward the first surface in one radial direction, and in the other radial direction, the portion of the peripheral region of the substrate is flat, free of warpage, and exhibits an asymmetric penetrating profile. Depending on the shape of the surface presented by the substrate, the direction in which part of the peripheral region is bent towards the first surface of the substrate is defined as a first orientation 201 and the direction in which part of the peripheral region is flat and free of warpage is defined as a second orientation 202. The first curvature bow of the substrate in the first orientation 201 and the second curvature bow2 of the substrate in the second orientation 202 are measured. In this embodiment, the first curvature bow1 is a negative value, the second curvature bow2 is 0, the value of bow1 is smaller than that of bow2, and the difference between the first curvature bow1 and the second curvature bow2 is obtained according to Δ bow = bow 1-bow.
The second surface of the sapphire substrate is sandblasted, the shape of the sandblasted area is a bowknot shape as shown in fig. 9, the intersection point of the first orientation 201 and the second orientation 202 of the sapphire substrate is taken as the center of a circle, the second orientation 202 of the sapphire substrate is taken as the symmetry axis, and the two opposite sectors are arranged, wherein the radius of each sector is the same as that of the sapphire substrate and is larger than or equal to 1 inch, the radius of the substrate is larger than 1 inch, the stress distribution of the sapphire with the radius smaller than 1 inch is relatively uniform, and most of the surface shapes are symmetrical surface shapes without adjustment.
The larger the value of Δ bow, the greater the difference between the first curvature bow and the second curvature bow2, the greater the degree of substrate stress non-uniformity, and the larger the area of the blast region fan should be, and therefore the larger the angle θ of the blast region fan should be. In this embodiment, the included angle θ of the fan shape of the sandblasted region is 30 ° to 120 °.
The sand species include diamond, silicon carbide, boron carbide, aluminum oxide, or silicon oxide. In this embodiment, the substrate is made of sapphire, and the hardness of sand should be greater than that of sapphire, and diamond, silicon carbide or boron carbide may be selected.
The larger the value of Δ bow, the greater the difference between the first and second curvatures bow, bow, and the greater the degree of substrate stress non-uniformity, the greater the need for a greater sandblasting pressure to adjust the difference between the second curvatures bow, 2. In this embodiment, the pressure p= -k Δ bow of the sand blasting is 0.1-10 Mpa/um, when the hardness of the sand is large, a smaller k value can be selected, and when the hardness of the sand is small, a larger k value can be selected.
In this embodiment, the pressure p of the sandblasting is between 0.01mpa and 100mpa, the pressure p of the sandblasting is proportional to the k value, the greater the k value is, the greater the pressure p of the sandblasting is, and the smaller the k value is, the pressure p of the sandblasting is reduced.
When the mesh number of the sand is more than 10000 meshes, the roughness of the second surface of the sapphire substrate can be reduced; when the mesh number of the sand is less than 50 mesh, the roughness of the second surface of the sapphire substrate becomes large. In order to ensure that the roughness of the second surface of the sapphire substrate is 0.9 μm to 1.2 μm, the mesh number of the sand in the embodiment is 50 mesh to 10000 mesh.
In this embodiment, the second surface of the substrate is sandblasted by impacting the second surface of the substrate with high-speed and high-pressure sand to generate a stress difference with the first surface, and the second curvature bow2 which is originally different from the first curvature bow1 is adjusted to the level of the first curvature bow1, so that the substrate has almost the same bending degree in each radial direction towards the first surface, and the surface shape of the substrate is a symmetrical surface shape like a circle or bowl.
In an alternative embodiment of the invention, as shown in fig. 10, the substrate is curved in one radial direction towards the second surface of the substrate and in a different radial direction towards the first surface of the substrate, the substrate assuming a saddle-type profile. According to this surface shape of the substrate, as shown in fig. 9, a direction in which the substrate is bent toward the first surface is defined as a first orientation 301, a direction in which the substrate is bent toward the second surface of the substrate is defined as a second orientation 302, and a first bending bow1 of the substrate in the first orientation 301 and a second bending bow2 of the substrate in the second orientation 302 are measured, respectively, in this embodiment, the first bending bow1 is a negative value, the second bending bow2 is a positive value, the value of bow1 is smaller than the value of bow2, and a difference between the first bending bow and the second bending bow2 is obtained according to Δ bow = bow1-bow2.
The second surface of the sapphire substrate is sandblasted, the shape of the sandblasted area is a bow-tie shape as shown in fig. 11, the intersection point of the first orientation 301 and the second orientation 302 of the sapphire substrate is used as a center of circle, the second orientation 302 of the sapphire substrate is used as a symmetrical axis, and the two opposite sectors are arranged, wherein the radius of each sector is the same as that of the sapphire substrate and is larger than or equal to 1 inch, in the current sapphire substrate processing industry, the radius of the substrate is larger than 1 inch, the stress distribution of the sapphire with the radius smaller than 1 inch is relatively uniform, and the surface shape is mostly in a symmetrical surface shape without adjustment.
The larger the value of Δ bow, the greater the difference between the first curvature bow and the second curvature bow2, the greater the degree of substrate stress non-uniformity, and the larger the area of the blast region fan should be, and therefore the larger the angle θ of the blast region fan should be. In this embodiment, the included angle θ of the fan shape of the sandblasted region is 30 ° to 120 °.
The sand species include diamond, silicon carbide, boron carbide, aluminum oxide, or silicon oxide. In this embodiment, the substrate is made of sapphire, and the hardness of sand should be greater than that of sapphire, and diamond, silicon carbide or boron carbide may be selected.
The larger the value of Δ bow, the greater the difference between the first and second curvatures bow, bow, and the greater the degree of substrate stress non-uniformity, the greater the need for a greater sandblasting pressure to adjust the difference between the second curvatures bow, 2. In this embodiment, the pressure p= -k Δ bow of the sand blasting is 0.1-10 Mpa/um, when the hardness of the sand is large, a smaller k value can be selected, and when the hardness of the sand is small, a larger k value can be selected.
In this embodiment, the pressure p of the sandblasting is between 0.01mpa and 100mpa, the pressure p of the sandblasting is proportional to the k value, the greater the k value is, the greater the pressure p of the sandblasting is, and the smaller the k value is, the pressure p of the sandblasting is reduced.
When the mesh number of the sand is more than 10000 meshes, the roughness of the second surface of the sapphire substrate can be reduced; when the mesh number of the sand is less than 50 mesh, the roughness of the second surface of the sapphire substrate becomes large. In order to ensure that the roughness of the second surface of the sapphire substrate is 0.9 μm to 1.2 μm, the mesh number of the sand in the embodiment is 50 mesh to 10000 mesh.
In this embodiment, the second surface of the substrate is sandblasted by impacting the second surface of the substrate with high-speed and high-pressure sand to generate a stress difference with the first surface, and the second curvature bow2 which is originally different from the first curvature bow1 is adjusted to the level of the first curvature bow1, so that the substrate has almost the same bending degree in each radial direction towards the first surface, and the surface shape of the substrate is a symmetrical surface shape like a circle or bowl.
Yet another embodiment of the present invention provides a method for manufacturing a semiconductor device, the method including:
step S100: providing a substrate and determining an asymmetric profile exhibited by the substrate, the substrate having a first surface and a second surface;
step S200: determining an asymmetric orientation of the asymmetric profile and measuring a degree of curvature of the substrate in the asymmetric orientation;
step S300: locally blasting the substrate in the asymmetric direction to enable the substrate to be converged from an asymmetric surface shape to a symmetric surface shape;
step S400: a light emitting structure is formed over the substrate converged to a symmetrical plane.
In the steps S100 to S300, the processing method of the substrate provided by the present invention is the same as that of the previous embodiment of the present invention, and will not be described herein. Wherein, step S400, forming at least one semiconductor epitaxial layer above the first surface of the substrate includes the steps of:
forming a first semiconductor layer over the substrate;
forming multiple quantum wells over the first semiconductor layer;
a second semiconductor layer of opposite conductivity to the first semiconductor layer is formed over the multiple quantum well.
In an alternative embodiment, N number (n=1000) of sapphire substrates are used for epitaxial growth, N/2 number of substrates are processed by the above substrate processing method, the remaining N/2 number of substrates are not processed, the N/2 number of substrates and the remaining N/2 number of substrates simultaneously comprise four types of fig. 1 to 4, and then the N/2 number of sapphire substrates after the sandblasting treatment according to the present invention and the remaining N/2 number of sapphire substrates without the sandblasting treatment are compared, so that the N/2 number of sapphire substrates after the sandblasting treatment according to the present invention can reach 100% of symmetrical surface types; after epitaxial growth, the average wavelength uniformity of the N/2 number of sapphire substrates subjected to the sand blasting treatment is improved by 5% compared with the average wavelength uniformity of the rest N/2 number of sapphire substrates not subjected to the sand blasting treatment.
Another embodiment of the present invention provides a substrate for epitaxial growth, the substrate having a first surface and a second surface, the substrate being manufactured by the substrate processing method described above, the substrate being converged from an asymmetric surface shape to a symmetric surface shape after being locally sandblasted.
Still another embodiment of the present invention provides a light emitting diode, including a substrate and a light emitting structure formed over the substrate, wherein the substrate is a substrate for epitaxial growth provided by the present invention.
As described above, the substrate and the processing method thereof, the light emitting diode and the manufacturing method thereof provided by the invention have at least the following beneficial technical effects:
in the method, firstly, the asymmetric surface type of the substrate is determined, the asymmetric orientation of the asymmetric surface type is determined, the substrate is subjected to local sand blasting treatment in the asymmetric orientation, uniform stress can be generated on the second surface (the surface with larger roughness) of the substrate by sand blasting, sand blasting parameters such as k value and sand blasting pressure can be adjusted, the size of the adjusted stress can be controlled, the bow-tie-shaped local sand blasting area is designed according to the characteristics of the annealed asymmetric surface type substrate, the warping of the substrate in the protruding area or the flat area is adjusted to the degree of protruding in a certain radial direction, the whole substrate is made to present a concave shape with almost the same bending degree in each radial direction, the asymmetric surface type is adjusted to be a symmetric surface type, and the substrate is made to present a symmetric surface type, such as a bowl-shaped (or concentric circle-shaped) substrate. And growing the epitaxial layer on the substrate converged to the symmetrical plane type is beneficial to reducing the wavelength dispersion of the epitaxial layer, namely, the wavelength of the epitaxial layer is converged, the convergence of the wavelength of the epitaxial layer is improved to directly influence the yield of subsequent devices, and the device yield is greatly improved.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (16)
1. A method of processing a substrate, comprising the steps of:
providing a substrate and determining an asymmetric profile exhibited by the substrate, the substrate having a first surface and a second surface;
determining an asymmetric orientation of the asymmetric profile and measuring a degree of curvature of the substrate in the asymmetric orientation;
in the asymmetric orientation, locally blasting the substrate to cause the substrate to converge from an asymmetric surface shape to a symmetric surface shape.
2. The method of processing a substrate according to claim 1, wherein an asymmetric orientation of the asymmetric surface type is determined, and a degree of curvature of the substrate in the asymmetric orientation is measured, further comprising the steps of:
determining a first orientation and a second orientation of the asymmetric profile, the first orientation and the second orientation being intersecting asymmetric orientations;
measuring a first curvature bow1 of the substrate in the first orientation along the first surface;
measuring a second bow bow2 of the substrate in the second orientation along the first surface;
defining the substrate to bend in an asymmetric orientation towards the first surface, the bending being negative;
the substrate is bent towards the second surface in an asymmetric direction, and the bending degree is a positive value;
the value of the first curvature bow1 is negative and the value of the first curvature bow is less than the value of the second curvature bow2, defining Δ bow = bow1-bow2.
3. A method of processing a substrate according to claim 3, wherein the surface of the substrate subjected to localized blasting is a second surface.
4. The method of processing a substrate according to claim 1, wherein the asymmetric surface shape exhibited by the substrate includes any one of the following types:
concentric ellipses, the substrate being curved in the same direction but different in curvature in the asymmetric direction;
a penetration type substrate which is curved in one direction and is not curved in the other direction asymmetric to the one direction;
saddle-shaped, the substrate being curved in opposite directions in an asymmetric direction.
5. The method of processing a substrate according to claim 4, wherein the step of locally blasting the substrate comprises: the second curvature bow2 is adjusted to the value of the first curvature bow1 to cause the substrate to converge from an asymmetric profile to a symmetric profile.
6. The method for processing a substrate according to claim 4, wherein the substrate is locally sandblasted, and the sandblasted area is bow-tie-shaped, and the specific shape is: and two opposite sectors taking the intersection point of the first orientation and the second orientation of the substrate as a center of a circle and taking the second orientation of the substrate as a symmetry axis.
7. The method of processing a substrate according to claim 7, wherein a radius r of the fan shape is the same as a radius of the substrate, and the radius r of the fan shape is 1 inch or more.
8. The method of claim 7, wherein the angle θ of the sectors is between 30 ° and 120 °.
9. The method of processing a substrate according to claim 1, wherein the substrate is locally sandblasted, and the type of sand comprises diamond, silicon carbide, boron carbide, aluminum oxide, or silicon oxide.
10. The method for processing a substrate according to claim 1, wherein the pressure p= -k Δ bow, k of the blasting is in the range of 0.1-10 Mpa/um.
11. The method for processing a substrate according to claim 10, wherein the blasting pressure p is 0.01mpa to 100mpa.
12. The method for processing a substrate according to claim 1, wherein the substrate is locally sandblasted, and the number of the sand is 50 mesh to 10000 mesh.
13. The preparation method of the light-emitting diode is characterized by comprising the following steps of:
providing a substrate and determining an asymmetric profile exhibited by the substrate, the substrate having a first surface and a second surface;
determining an asymmetric orientation of the asymmetric profile and measuring a degree of curvature of the substrate in the asymmetric orientation;
locally blasting the substrate in the asymmetric direction to enable the substrate to be converged from an asymmetric surface shape to a symmetric surface shape;
a light emitting structure is formed over the substrate converged to a symmetrical plane.
14. The method of claim 13, wherein the light emitting diode is formed by a process of,
forming a light emitting structure over the substrate comprises the steps of:
forming a first semiconductor layer over the substrate;
forming multiple quantum wells over the first semiconductor layer;
a second semiconductor layer of opposite conductivity to the first semiconductor layer is formed over the multiple quantum well.
15. A substrate for epitaxial growth, said substrate having a first surface and a second surface, characterized in that,
the substrate is manufactured by the substrate processing method according to any one of claims 1 to 12, and the substrate is converged from an asymmetric surface shape to a symmetric surface shape after being locally sandblasted.
16. A light-emitting diode comprising a substrate and a light-emitting structure formed over the substrate, wherein the substrate is the epitaxial substrate according to claim 15.
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| CN202211188365 | 2022-09-27 | ||
| CN2022111883652 | 2022-09-27 |
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