A substrate processing method and a semiconductor device manufacturing method

Abstract

The present application aims to provide a substrate processing method and a semiconductor device manufacturing method. In the present application, before cutting the ingot, the side surface of the ingot is first treated with a surface treatment agent, so that the ingot reacts with the surface treatment agent to form a modified layer during subsequent annealing. The ingot after surface treatment is cut to obtain a plurality of substrates, and the outer edge portion of each substrate includes a modified region. Due to the difference in crystal lattice and thermodynamic properties between the modified region and the material of the middle region of the substrate, a stable stress region is formed in the range of the modified layer region of the substrate, the direction and degree of distortion / bending of the substrate are controlled, the surface shape of the substrate is optimized, and the processing quality and quality of the substrate are improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a substrate processing method and a semiconductor device manufacturing method. Background Technology

[0002] In the manufacturing process of semiconductor devices, epitaxial layers are typically grown using growth substrates. For these substrates, substrate twisting / bending is the most significant factor affecting epitaxial uniformity. In existing technologies, crystal growth moles can typically reach over 100 kg, resulting in large sizes and poor temperature field uniformity during growth, leading to significant thermal stress in the crystal. Ingot extraction involves removing ingots of various diameters from the mole. Due to this mechanical processing, substantial mechanical stress is generated around the ingots. The presence of both thermal and mechanical stresses, and their random and uncontrollable nature, results in uneven stress on the final substrate, causing twisting / bending and resulting in an asymmetrical substrate profile. This asymmetrical substrate profile reduces the wavelength convergence of the subsequently formed epitaxial layer. The wavelength uniformity of the epitaxial layer directly affects the yield of the final device.

[0003] Based on the above problems, it is necessary to provide a substrate processing method to improve the processing quality and grade of the substrate. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a substrate processing method and a semiconductor device manufacturing method. In this invention, before cutting the crystal ingot, the sides of the crystal ingot are first treated with a surface treatment agent, causing the crystal ingot to react with the surface treatment agent during the subsequent annealing process to form a modified layer. The surface-treated crystal ingot is then cut to obtain multiple substrates. The outer edge of each substrate includes a modified region. Due to the difference in lattice and thermodynamic properties between the modified region and the middle region of the substrate, the modified region forms a stable stress region, which can control the direction and degree of twisting / bending of the substrate, optimize the substrate surface shape, and improve the processing quality and grade of the substrate.

[0005] To achieve the above and other related objectives, one embodiment of the present invention provides a substrate processing method, which includes the following steps:

[0006] The side surfaces of the crystal rod formed by crystal growth are treated with a surface treatment agent;

[0007] The surface-treated crystal rod is annealed to react the side of the crystal rod with the surface treatment agent to form a modified layer on the side of the crystal rod.

[0008] The crystal rod is cut to obtain multiple substrates, each of which has a modified region at its outer edge.

[0009] Optionally, the surface treatment of the ingot comprises:

[0010] coating a surface treatment agent on the side surface of the ingot, and baking the ingot at a temperature of 100-200°C for 0-2h.

[0011] Optionally, the surface treatment agent is coated on the side surface of the ingot at a coating amount of 0.1-100mg / cm 2 2 .

[0012] Optionally, before the surface treatment of the ingot, the method further comprises the following steps:

[0013] providing a modifier, a catalyst, a dispersant and a solvent;

[0014] mixing the modifier, the catalyst, the dispersant and the solvent to obtain the surface treatment agent.

[0015] Optionally, the annealing of the surface-treated ingot further comprises the following steps:

[0016] putting the ingot coated with the surface treatment agent into a heating furnace;

[0017] annealing the ingot at a temperature of 30-3000°C for 0.1h-30 days.

[0018] Optionally, the annealing of the surface-treated ingot further comprises the following steps:

[0019] warming up: warming up the heating furnace to a temperature of 100-2000°C at a warming-up rate of 0.5-200°C / min;

[0020] holding: holding at a temperature of 100-2000°C for 0.1h-500h;

[0021] cooling down: cooling down the heating furnace to room temperature at a cooling-down rate of 0.5-200°C / min.

[0022] Optionally, the modified layer formed on the side surface of the ingot has a depth of greater than 0 and less than 2mm.

[0023] Optionally, the modified region of the substrate is an annular ring with the center of the substrate as the center, extending inward from the edge of the outer circle of the substrate, and the difference between the outer diameter and the inner diameter of the annular ring is greater than 0 and less than 200μm.

[0024] Optionally, the cut substrate is ground;

[0025] the ground substrate is annealed, chamfered and polished.

[0026] ​Optionally, the substrate chamfered face width is greater than 200 μm.

[0027] A semiconductor device manufacturing method, characterized by comprising the following steps:

[0028] Providing a substrate obtained by the above substrate processing method;

[0029] Forming at least one semiconductor layer on the first surface or the second surface of the substrate;

[0030] Etching the semiconductor layer.

[0031] Optionally, forming at least one semiconductor layer on the first surface or the second surface of the substrate further comprises the following steps:

[0032] Forming a first semiconductor layer on the substrate;

[0033] Forming an active layer above the first semiconductor layer;

[0034] Forming a second semiconductor layer above the active layer, the second semiconductor layer having a conductivity opposite to that of the first semiconductor layer.

[0035] Optionally, the semiconductor device manufacturing method further comprises forming a first electrode and a second electrode in communication with the first semiconductor layer and the second semiconductor layer, respectively.

[0036] As described above, the substrate processing method and the semiconductor device manufacturing method provided by the present application at least have the following beneficial effects: in the method of the present application, first, the side surface of the crystal bar is subjected to surface treatment by using a surface treatment agent, so that the crystal bar reacts with the surface treatment agent to form a modified layer in the subsequent annealing process; the crystal bar after surface treatment is cut to obtain a plurality of substrates, and the outer edge portion of each substrate includes a modified region; due to the difference in crystal lattice and thermodynamic properties between the modified region and the material in the middle region of the substrate, the thermal expansion coefficient of the modified region is different from that of the material in the middle region of the substrate; in the cooling process, the modified region generates consistent stress, so that the substrate forms convergent and controllable distortion / bending; the distortion / bending direction and degree of the plurality of substrates tend to be the same, so the surface shape of the plurality of substrates tends to be consistent; the processing quality and the quality of the substrates can be improved; in addition, the modified region is chamfered in the subsequent chamfering process, and does not have a negative impact on the electrical parameters in the subsequent epitaxial process.

[0037] The semiconductor device of the present application is processed by the above method, so compared with the semiconductor device obtained by conventional substrate processing, the divergence of the wavelength of the epitaxial layer is reduced, the wavelength of the epitaxial layer is more convergent, and the yield of the semiconductor device is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The diagram shows the fabrication process for a conventional substrate.

[0039] Figure 2 The diagram shown is a flowchart of the substrate processing in one embodiment of the present invention.

[0040] Figure 3 The image shown is a side view of a crystal rod according to an embodiment of the present invention. Detailed Implementation

[0041] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0042] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Although the illustrations only show components relevant to the present invention and are not drawn according to the actual number, shape, and size of components in implementation, the shape, quantity, positional relationship, and proportion of each component in actual implementation can be arbitrarily changed under the premise of realizing the technical solution of this invention, and the component layout may also be more complex. Therefore, it is foreseeable that the shape in the schematic diagram may vary, for example, due to manufacturing technology and / or tolerances. Therefore, the exemplary embodiments should not be considered as limited to the specific shape of the area shown in the figure, but may also include shape deviations caused by, for example, manufacturing processes. In the figures, for clarity, the length and size of certain layers and areas may be enlarged. Similar reference numerals in the figures indicate similar parts. It should also be understood that when a layer is referred to as "located on other layers or substrates," the layer may be directly located on other layers or substrates, or there may be intermediate layers.

[0043] Substrate fabrication is a crucial step in semiconductor device manufacturing, and its yield directly impacts device performance. For example... Figure 1The shown is a processing flow chart of a conventional substrate, the substrate is generally a wafer obtained by wire cutting of a crystal bar formed by crystal growth, in the prior art, the crystal bar can reach more than 100 kg, the size is large, the temperature field uniformity in the crystal growth process is not high, which leads to a large thermal stress of the crystal. The bar pulling is to pull out the crystal bar of various diameters from the crystal bar, because it is mechanical processing, a large mechanical stress will be generated around the crystal bar. Due to the existence of thermal stress and mechanical stress, and random uncontrollable, it will lead to the stress of the substrate obtained by the final processing to be uneven, and the substrate will be twisted / bent, so that the substrate presents an asymmetric surface type, the asymmetric surface type of the substrate will lead to the convergence of the wavelength of the subsequently formed epitaxial layer to be reduced. The uniformity of the wavelength of the epitaxial layer directly affects the yield of the later device. The application provides a substrate processing method and a semiconductor device preparation method.

[0044] As shown in the drawings, Figure 2 The shown is a processing flow chart of a substrate in the embodiment, in the embodiment, the above-mentioned crystal bar can be any crystal used for semiconductor device manufacturing, for example, can be glass, compound semiconductor, metal and alloy, oxide, nitride, group III-V compound, group II-VI compound, group IV main group element and compound, halide, silicate, carbonate, etc. The crystal bar selected in the embodiment is a sapphire crystal bar, and the crystal growth process is generally as follows: first, put the raw material aluminum oxide into a crucible, heat the crucible and the aluminum oxide therein, heat the temperature to more than 2000℃, so that the aluminum oxide is melted into a molten state; then, seed crystal is put from the top of the liquid surface, and the seed crystal is in contact with the liquid surface; then, the shoulder is slowly pulled up, the crystal weight is uniformly increased, and the crystal diameter is increased to a predetermined diameter; the equal diameter growth is uniformly pulled up, and the crystal is grown with equal diameter; the cutting is separated, the crystal diameter is reduced, and the crystal is completely separated from the solution by forming a sharp point, and the crystal after being separated from the solution is cooled, thus obtaining a sapphire crystal.

[0045] The bar pulling machine and the high-speed rotating bar pulling cutter are used to pull the sapphire crystal bar along the direction parallel to the sapphire crystal bar surface, thus obtaining the sapphire crystal bar, at this time, due to the existence of thermal stress and mechanical stress in the processing process of the sapphire crystal bar, the defect density of the substrate directly obtained by processing will be increased, and the warpage will be large.

[0046] Therefore, as shown in the drawings, Figure 3As shown, a surface treatment agent is coated on the side 1 of the sapphire crystal rod to perform surface treatment on the sapphire crystal rod. In this embodiment, the surface treatment agent includes a modifier: an aluminate, a silicate, a carbonate, a hydroxide, an oxide, or a halide, etc., a catalyst: a reducing material (carbon, silicon, a sulfide, a metal element, an iodide, a divalent iron salt, and other low-valence compounds), an oxidizing material (potassium permanganate, dichromate, chlorate, nitrate, a trivalent iron salt, a divalent copper salt, and other high-valence compounds), an acid, a base, or an ionic salt, a dispersing agent: at least one of castor oil, triolein, and a phosphate ester, a solvent: various solvents such as alcohols, ketones, toluenes, ethers, esters, and a mixed solvent of one or two of alcohols and ketones or toluenes. The above-mentioned modifier, catalyst, dispersing agent, and solvent are uniformly mixed and then coated on the surface of the substrate. The thickness and concentration of the surface treatment agent can be determined according to the depth of the surface treatment on the sapphire crystal rod. In this embodiment, the thickness of the surface treatment agent is greater than 0.1 mm, and the coating amount of the surface treatment agent is 0.1 mg / cm 2 100 mg / cm 2 .

[0047] After the side of the sapphire crystal rod is coated with the surface treatment agent, the sapphire crystal rod is baked, for example, at a temperature ranging from 100°C to 200°C for 0 to 2 hours. During the baking process, the surface treatment agent hardly reacts with the substrate or reacts to a very small extent. However, during the process, the surface treatment agent is initially dried so as to be closely attached to the sapphire crystal rod, which facilitates the reaction with the sapphire crystal rod during the subsequent annealing process.

[0048] After the above-mentioned surface treatment, the sapphire crystal rod with the surface treatment agent is placed in a heating furnace to perform an annealing process. In this embodiment, the annealing temperature is between 30°C and 3000°C, and the annealing time is about 0.1 hour to 30 days.

[0049] In an optional embodiment, the annealing process mainly includes: a heating stage, in which the heating furnace is heated to a temperature ranging from 100°C to 2000°C at a heating rate of 0.5 to 200°C / min; a holding stage, in which the heating furnace is held at a temperature ranging from 100°C to 2000°C for 0.1 hour to 500 hours; and a cooling stage, in which the heating furnace is cooled to room temperature at a cooling rate of 0.5 to 200°C / min. In a more preferred embodiment, the heating furnace is heated to a temperature ranging from 1300°C to 1800°C at a heating rate of 1 to 20°C / min, held at a temperature ranging from 1300°C to 1800°C for 1 to 100 hours, and then cooled to room temperature at a cooling rate of 1 to 20°C / min.

[0050] In the above heat preservation stage, the surface treatment agent fully reacts with the sapphire crystal bar. In this embodiment, the surface treatment agent is taken as an example of calcium acetate ethanol solution. In the heating stage, the calcium acetate solution loses all ethanol, and the calcium acetate decomposes into acetone and calcium carbonate; in the high-temperature stage, the calcium carbonate decomposes as follows:

[0051] CaCO3→ CaO + CO2↑

[0052] The reaction product CaO of the above decomposition reaction has high reactivity, and under high-temperature conditions, it will react with the sapphire crystal bar, and the specific reaction is as follows:

[0053] CaO + Al2O3→ xCaO·yAl2O3

[0054] In the above reaction formula, x and y are both greater than zero, and different combinations of x and y represent different reaction products. Under the high-temperature conditions of the heat preservation stage described in this embodiment, there are multiple reaction products.

[0055] In the annealing process, the modifier in the surface treatment agent reacts under the action of the catalyst from the side surface of the sapphire crystal bar to form a modified layer. With the passage of time, the modifier continuously diffuses to the inside of the side surface of the sapphire crystal bar, gradually reacts, and the thickness of the modified layer continuously increases. By controlling the heat preservation temperature and the heat preservation time, the thickness of the modified layer can be controlled. For example, according to the requirements of the face width in the subsequent chamfering process, the thickness of the modified layer can be controlled in the range of 0-200 μm.

[0056] After the above surface treatment and annealing, the surface of the side surface of the sapphire crystal bar is modified. The modified structure lattice and thermodynamic properties are different from those of sapphire, and the stress region in the modified region is more stable than that of the sapphire substrate.

[0057] After the annealing is completed, the sapphire wafer is subjected to line cutting, grinding, annealing, chamfering, copper throwing and polishing. In this embodiment, the line cutting and grinding processes are the same as those of a conventional sapphire substrate. In this embodiment, the chamfered surface of the sapphire substrate has a width of greater than 200 μm. In the above processing method, the depth of the modified layer on the side surface of the sapphire wafer is 0-200 μm. Therefore, the modified region of the sapphire substrate obtained after cutting is a circular ring with the center of the sapphire substrate, the outer edge of the sapphire substrate and the center of the substrate, the difference between the outer diameter and the inner diameter of the circular ring is greater than 0 and less than 200 μm. In the chamfering process, the modified region is chamfered into a surface area, which does not affect the electrical parameters of the sapphire substrate in the subsequent epitaxial process. The modified region is a structure obtained by high-temperature annealing. In the annealing process, atoms in the modified material enter the sapphire surface, so that the atoms are rearranged. Due to the difference in thermal expansion coefficient, a relatively stable stress difference is formed at the interface between the modified region and the intermediate region of the substrate during the cooling process. Specifically, the stress generated in the modified region is much greater than the stress in the intermediate region of the substrate. Therefore, the stress difference between the modified region and the intermediate region of the substrate tends to be consistent among multiple substrates. Thus, the stress difference among multiple substrates can be converged, the direction and degree of distortion / bending of multiple substrates tend to be the same, thereby optimizing the surface shape of the substrate and improving the processing quality and quality of the substrate.

[0058] Another embodiment of the present application provides a semiconductor device manufacturing method, which comprises the following steps:

[0059] A substrate is provided, which is obtained by the above substrate processing method. The substrate can also be any substrate suitable for semiconductor manufacturing, for example, glass, compound semiconductors and insulators, metals and alloys, oxides, nitrides, group III-V compounds, group II-VI compounds, group IV main group elements and compounds, halides, perovskite materials, silicates, carbonates, aluminates, etc.

[0060] At least one semiconductor layer is formed on the first surface or the second surface of the substrate. In this embodiment, the formation of the semiconductor layer on the sapphire substrate is taken as an example. The formation of the at least one semiconductor layer comprises: first forming a first semiconductor layer on the substrate, then forming an active layer above the first semiconductor layer, and then forming a second semiconductor layer above the active layer, the second semiconductor layer having a conductivity opposite to that of the first semiconductor layer. In addition, a first electrode and a second electrode are respectively formed to communicate with the first semiconductor layer and the second semiconductor layer.

[0061] The first semiconductor layer can be an N-type semiconductor layer and the second semiconductor layer can be a P-type semiconductor layer, or the first semiconductor layer can be a P-type semiconductor layer and the second semiconductor layer can be an N-type semiconductor layer, and the active layer can be a multiple quantum well. The at least one semiconductor layer is etched to form a semiconductor light-emitting structure.

[0062] In the semiconductor device manufacturing method, the substrate is processed by the substrate processing method, and the yield of the semiconductor device is improved.

[0063] As described above, the substrate processing method and the semiconductor device manufacturing method have the following beneficial technical effects. In the method, the side surface of the ingot is treated by the surface treatment agent before the ingot is cut. The ingot reacts with the surface treatment agent to form a modified layer during subsequent annealing. The ingot is cut after the surface treatment to obtain a plurality of substrates. The outer edge portion of each substrate includes a modified region. The thermal expansion coefficient of the modified region is different from that of the material in the middle region of the substrate due to the difference in the crystal lattice and the thermodynamic properties between the modified region and the middle region of the substrate. Stress is generated in the modified region during the cooling process, and the stress is much greater than that in the middle region of the substrate. Therefore, a relatively stable stress difference is formed at the interface between the modified region and the middle region of the substrate. The stress difference between the plurality of substrates is converged, and the direction and degree of distortion / bending of the plurality of substrates tend to be the same. Thus, the surface shape of the substrate is optimized, and the processing quality and the quality of the substrate are improved. The semiconductor device is processed by the method, and therefore, compared with the semiconductor device obtained by conventional substrate processing, the wavelength divergence of the epitaxial layer is reduced, the wavelength of the epitaxial layer is more converged, and the yield of the semiconductor device is greatly improved.

[0064] The above embodiments only illustrate the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical idea of the present application should be covered by the claims of the present application.

Claims

1. A method for processing a substrate, comprising the steps of: surface-treating a side surface of a crystal bar formed by crystal growth; annealing the crystal bar after the surface treatment, so that the side surface of the crystal bar reacts with the surface treatment agent to form a modified layer on the side surface of the crystal bar; and cutting the crystal bar to obtain a plurality of substrates, each of which comprises a modified region in an outer edge portion, the surface treatment agent comprising a modifier, a catalyst, a dispersant, and a solvent, wherein the solvent comprises an alcohol, a ketone, a toluene, an ether, or an ester, and a stress difference between the modified region and an intermediate region of the substrate tends to be uniform, a convergence of the stress difference controls a direction and a degree of a distortion or a bending of the substrate to be uniform. The surface treatment of the crystal bar comprises coating the side surface of the crystal bar with the surface treatment agent and baking the crystal bar at a temperature of 100-200℃ for 0-2 hours. The coating amount of the surface treatment agent on the side surface of the crystal bar is 0.1-100 mg / cm2. Before the surface treatment of the crystal bar, the method further comprises the steps of: providing the modifier, the catalyst, the dispersant, and the solvent; and mixing the modifier, the catalyst, the dispersant, and the solvent to obtain the surface treatment agent. The annealing of the crystal bar after the surface treatment further comprises the steps of: placing the crystal bar coated with the surface treatment agent into a heating furnace; and annealing the crystal bar at a temperature of 30-3000℃ for 0.1-30 days.

2. The method of processing a substrate according to claim 1, wherein, The annealing of the crystal bar after the surface treatment further comprises the steps of: heating the heating furnace at a heating rate of 0.5-200℃ / min to a temperature of 100-2000℃; maintaining the temperature of 100-2000℃ for 0.1-500 hours; and cooling the heating furnace at a cooling rate of 0.5-200℃ / min to room temperature.

3. The method of processing a substrate according to claim 2, wherein, The modified layer formed on the side surface of the crystal bar has a depth of greater than 0 and less than 2 mm.

4. The method of processing a substrate according to claim 1, wherein, The modified region of the substrate is a circular ring extending inward from an outer edge of the substrate, and a difference between an outer diameter and an inner diameter of the circular ring is greater than 0 and less than 200 μm. The method further comprises the steps of: grinding the substrates obtained by the cutting; and annealing, chamfering, and polishing the substrates after the grinding. The chamfering of the substrate has a face width of greater than 200 μm.

5. The method of processing a substrate according to claim 1, wherein, The method further comprises the steps of: providing the substrate obtained by the processing method according to any one of claims 1-10; forming at least one semiconductor layer on a first surface or a second surface of the substrate; and etching the semiconductor layer. The method for manufacturing a semiconductor device according to claim 11, wherein the forming of the at least one semiconductor layer on the first surface or the second surface of the substrate further comprises the steps of: forming a first semiconductor layer on the substrate; forming an active layer above the first semiconductor layer; and forming a second semiconductor layer above the active layer, the second semiconductor layer having a conductivity opposite to that of the first semiconductor layer. The method further comprises the steps of:

6. The method of processing a substrate of claim 1, wherein, ​ ​ ​ ​ 7. The method of processing a substrate according to Claim 1, wherein, ​ 8. The method of processing a substrate according to claim 1, wherein, ​ 9. The method of processing a substrate according to claim 1, wherein ​ ​ ​ 10. The method of processing a substrate according to claim 9, wherein, ​ 11. A method of manufacturing a semiconductor device, characterized by, ​ ​ ​ ​ ​ ​ ​ ​ ​ 13. The semiconductor device manufacturing method according to claim 12, wherein ​ A first electrode and a second electrode are formed in communication with the first semiconductor layer and the second semiconductor layer, respectively.

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