A method for fine regulation of macro-damage and sub-damage on surface of indium arsenide substrate

Abstract

The application discloses a method for fine regulation of macroscopic damage and sub-damage on an indium arsenide substrate surface, and comprises the following steps: S1, thinning the substrate by using a diamond blade; S2, mechanically grinding the substrate by using alumina or other abrasives to remove macroscopic surface defects and cutting marks generated in the thinning process; S3, performing chemical mechanical polishing to remove macroscopic damages such as scratches generated in the mechanical grinding process; S4, performing chemical polishing on a multilayer structure porous high-surface-area composite polishing pad to effectively remove a sub-damage layer; S5, soaking and cleaning the substrate by using a soaking liquid; and S6, performing secondary cleaning and drying by using megasonic waves. The method is simple in process, and by accurately regulating process parameters and using the composite polishing pad, the surface quality of the indium arsenide substrate is effectively improved, and a non-damage high-quality substrate is provided for semiconductor device manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor material surface treatment technology, specifically relating to a method for fine control of macroscopic and sub-damage on the surface of an indium arsenide substrate. Background Technology

[0002] Indium arsenide, as an important group III-V compound semiconductor material, is a major substrate material for the fabrication of long-wave infrared detectors and laser epitaxy due to its excellent properties such as high electron mobility and narrow bandgap.

[0003] Indium arsenide is a typical soft and brittle semiconductor material, with a critical shear stress (CRSS) of only 0.8 N·mm. -2 In the surface treatment of indium arsenide substrates, whether through mechanical cutting, grinding, or chemical mechanical polishing, a sub-damage layer inevitably forms on the substrate surface. This sub-damage layer contains crystal defects such as lattice distortion, dislocations, and vacancies, and its thickness is typically between tens and hundreds of nanometers. The presence of these sub-damage defects severely affects the performance of the indium arsenide substrate. From an electrical performance perspective, the sub-damage layer increases the scattering probability of charge carriers and reduces electron mobility. From an optical performance perspective, sub-damage defects introduce a large number of non-radiative recombination centers, reducing the luminous efficiency of light-emitting devices. During the epitaxial growth of devices, the sub-damage layer leads to an increase in lattice mismatch between the epitaxial layer and the substrate, causing an increase in the defect density in the epitaxial layer, affecting the crystal quality of the epitaxial layer and the reliability of the device.

[0004] Currently, methods for removing damage layers from semiconductor substrate surfaces mainly include chemical mechanical polishing (CMP), chemical etching, and ion beam etching. However, these methods have many problems when applied to indium arsenide substrates. Although CMP can achieve surface planarization, for soft materials like indium arsenide, abrasive particles can easily embed into the substrate surface during polishing, introducing new impurities and damage. Traditional chemical etching is difficult to precisely control the etching rate and etching uniformity, easily leading to over-etching or under-etching. Although ion beam etching has high etching precision, high-energy ion bombardment can cause secondary damage to the substrate surface, forming new defect layers.

[0005] Therefore, there is an urgent need to develop a method for finely controlling macroscopic and sub-damage on the surface of indium arsenide substrates. Summary of the Invention

[0006] This invention aims to provide a method for finely controlling macroscopic and sub-damage on the surface of indium arsenide substrates. By precisely controlling process parameters and innovatively using composite polishing pads for chemical polishing, the sub-damage layer can be accurately removed, effectively improving the crystal quality and surface flatness of the indium arsenide substrate surface, and providing high-quality substrate materials for the high-performance manufacturing of subsequent semiconductor devices.

[0007] The method for removing the sub-damaged layer on the surface of an indium arsenide substrate according to the present invention specifically includes the following steps: S1, thinning: Using diamond blades to thin the substrate, the original indium arsenide substrate is cut to the target thickness. This step effectively removes most of the unnecessary substrate material, laying the foundation for subsequent fine processing. During the cutting process, cutting parameters, such as the cutting rate, must be strictly controlled to reduce initial damage introduced by the cutting.

[0008] S2, Mechanical grinding: Mechanical polishing of the thinned substrate aims to remove macroscopic damage generated during the thinning process and to initially smooth the substrate surface. During polishing, abrasives such as alumina, silicon carbide, and diamond can be used in the polishing slurry. The abrasive particles in the slurry roll, squeeze, and scrape between the polishing disc and the substrate, removing material from the substrate surface. Simultaneously, it is crucial to control parameters such as polishing pressure, polishing disc rotation speed, and polishing time to ensure uniform polishing results and avoid over-polishing that could cause further damage.

[0009] S3, Chemical Mechanical Polishing (CMP): Chemical mechanical polishing (CMP) utilizes the synergistic effect of mechanical and chemical processes to remove scratches and other damage introduced from the previous process. During CMP, the abrasive particles in the polishing slurry interact physically and chemically with the substrate surface, improving surface smoothness while removing a certain thickness of material. Parameters such as polishing pressure, polishing disc rotation speed, and polishing slurry flow rate need to be adjusted appropriately.

[0010] S4, Chemical Polishing (CP): After chemical mechanical polishing (CMP), the presence of abrasive particles introduces a sub-damage layer onto the indium arsenide substrate surface. Chemical polishing (CMP) removes this sub-damage layer by combining the abrasive action of the polishing pad with the chemical action of the polishing slurry. This process corrodes the substrate surface material, causing oxides to form and dissolve into the polishing slurry. This removes macroscopic surface damage, sub-damage, abrasive particles, and polishing mist adhering to the substrate surface. Strict control of factors such as CMP time, CMP pressure, CMP grinding wheel speed, CMP slurry volume, CMP slurry ratio, and CMP slurry pH is crucial to ensure stable polishing rate and surface quality.

[0011] A multi-layered, porous, high-surface-area composite polishing pad is employed. The composite polishing pad comprises a substrate layer and a polishing layer. The substrate layer provides stable support and appropriate elasticity for the polishing process, while the polishing layer includes a coarse polishing layer, a semi-fine polishing layer, and a fine polishing layer. The composite polishing pad has a gradient pore structure, with large pores on the upper layer for rapid liquid storage and small pores on the lower layer for conveying the polishing slurry. The composite polishing pad has a high surface area, which can increase the contact area with the polishing slurry and the wafer through nanoscale pores and microgrooves. The chemical polishing solution is prepared as follows: 0.1 mol / L sodium hypochlorite 15-20 vol%, 30% hydrogen peroxide 30-40 vol%, 1 mol / L ammonium persulfate 10-15 vol%, and the remainder is water. The pH of the solution is then adjusted to 5-7 using a pH adjuster. Chemical polishing pressure is 50-100 g / cm 2 The chemical polishing disc rotation speed is 15-25 rpm, the chemical polishing fluid flow rate is 1.5-3.0 mL / min, and the chemical polishing time is 15-20 min.

[0012] S5, Cleaning: After chemical polishing, the substrate is quickly sprayed with ultrapure water. This prevents surface oxidation and further removes residual particulate contaminants. Subsequently, it is immersed in an immersion solution to thoroughly remove any remaining chemical polishing solution and other impurities, ensuring a clean substrate surface.

[0013] S6, Drying: Mega-sound rotary cleaning is used to further remove surface contaminants, and drying is carried out by nitrogen blowing or centrifugal drying.

[0014] Furthermore, the diamond grinding wheel used in the thinning method in step S1 has a mesh size of 6000 or higher, a cutting rate of 1.0-3.0 μm / min, and a preferred thinning thickness of ≥30 μm is used to remove wafer cutting damage.

[0015] Furthermore, in step S2, the mechanical grinding abrasive can be one or more of the following: alumina, silicon carbide, diamond, etc., with a D50 (median particle size) of 3µm to 5µm. The mechanical grinding pressure is 200-300 g / cm. 2 The mechanical grinding disc rotation speed is 5-15 rpm, the mechanical grinding fluid flow rate is 10-20 mL / min, and the time is 10-20 min.

[0016] Further, the CMP abrasive in step S3 is one or more of silicon dioxide, diamond, magnesium oxide, cerium oxide, etc., with a particle size of 80-120 nm. The chemical mechanical polishing slurry contains 5-10 vol% of an oxidant, which may be one or more of hydrogen peroxide, nitric acid, sodium hypochlorite, potassium dichromate, etc., and contains 25-30 vol% colloidal abrasive, with the remainder being water. The chemical mechanical polishing pressure is 300-350 g / cm³. 2 The chemical mechanical polishing (CMP) grinding disc rotation speed is 35-50 rpm, the CMP slurry flow rate is 3-5 mL / min, and the time is 90-120 min.

[0017] Furthermore, the CP in step S4 differs from conventional chemical polishing processes. The CP of this invention employs a multi-layered, porous, high-surface-area composite polishing pad. This multi-layered composite polishing pad includes a substrate layer and a polishing layer. The substrate layer is further divided into a rigid substrate layer and an elastic substrate layer, providing stable support and appropriate elasticity for the polishing process. The polishing layers are a coarse polishing layer, a semi-fine polishing layer, and a fine polishing layer, each bonded together by an elastic layer. The composite polishing pad has abundant pores of varying sizes, forming a gradient pore structure. The upper layer has large pores for rapid liquid storage, while the lower layer has small pores for uniform polishing liquid delivery, facilitating the storage, transport, and uniform distribution of the polishing liquid. The composite polishing pad has a high surface area, increasing the contact area with the polishing liquid and the wafer through nanoscale pores and microgrooves. The chemical polishing pressure is 50-100 g / cm³. 2 The chemical polishing disc rotation speed is 15-25 rpm, the chemical polishing fluid flow rate is 1.5-3.0 mL / min, and the chemical polishing time is 15-20 min.

[0018] Further, the chemical polishing solution in step S4 is prepared as follows: 0.1 mol / L sodium hypochlorite 15-20 vol%, 30% hydrogen peroxide 30-40 vol%, 1 mol / L ammonium persulfate 10-15 vol%, the remainder being water, and the pH adjuster is the weak organic acid lactic acid. The preferred chemical polishing solution has a pH of 5-6.

[0019] Furthermore, the soaking solution used in step S5 can be anhydrous ethanol, methanol, toluene, acetone, or other organic solvents, with a soaking time of ≥30 min and a soaking temperature of 60-70℃.

[0020] Furthermore, in step S6, if nitrogen blowing is used for the drying process, the nitrogen pressure should be ≤0.2MPa and the temperature ≤35℃ to avoid damage to the substrate surface due to excessive airflow or high temperature; if centrifugal drying is used, the rotation speed should be 3000-5000rpm and the drying time should be 30-60s to ensure that the moisture on the substrate surface is completely removed and that the substrate does not shift or get damaged during the drying process, ultimately obtaining a clean and dry indium arsenide substrate.

[0021] The present invention has the following advantages and effects: 1. Precise removal of sub-damaged layers: By precisely controlling various process parameters and using composite polishing pads, it is possible to precisely remove the sub-damaged layers on the surface of indium arsenide substrates, providing high-quality substrates without damage for semiconductor device manufacturing.

[0022] 2. Significantly improve crystal surface quality: By introducing an innovative damage removal process, defects such as stress layers, scratches, and shallow marks on the substrate surface can be effectively eliminated, providing a higher quality base material for subsequent semiconductor device manufacturing.

[0023] 3. Ensuring High-Performance Semiconductor Device Manufacturing: High-quality indium arsenide substrates are crucial for achieving high-performance semiconductor devices. The substrate material provided by this invention, due to its excellent crystal quality and flatness, can effectively reduce device defects during subsequent device manufacturing processes.

[0024] 4. Strong Process Compatibility and Repeatability: The process steps and parameters of this invention have been systematically optimized, exhibiting good compatibility with existing semiconductor manufacturing processes and facilitating widespread application on existing production lines. Furthermore, by clearly defining the specific parameters and operating conditions for each process step, this method achieves high repeatability, enabling the stable production of high-quality indium arsenide substrates, ensuring product quality consistency, reducing defect rates during production, and improving production efficiency. This results in significant economic benefits and promising industrial application prospects. Attached Figure Description

[0025] Figure 1 The surface treatment steps for the indium arsenide substrate of the invention.

[0026] Figure 2 The images are optical microscope images after the substrate processing is completed, where a and b are optical microscope images after the substrate processing is completed in Example 2 and Comparative Example 1, respectively.

[0027] Figure 3 These are sub-damage corrosion diagrams, where a, b, c, and d are sub-damage corrosion diagrams for Comparative Example 1, Example 1, Example 2, and Example 3, respectively.

[0028] Figure 4 The diagram shows the location and thickness distribution of the oxide layer. In the diagram, 4a is the location of the oxide layer on a 2-inch indium arsenide substrate, and 4b is the thickness distribution of the oxide layer in Examples 1, 2, and 3.

[0029] Figure 5 The image shows the surface roughness test results for Example 2. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1 A method for finely controlling macroscopic and sub-damage on the surface of an indium arsenide substrate includes the following steps: S1, Diamond thinning of indium arsenide single crystal slices: A 2-inch (100) indium arsenide single crystal was thinned using a 6000-mesh diamond grinding wheel at a cutting rate of 1.2 μm / min on both sides, with a thinning thickness of 50 μm on each side.

[0032] S2, Mechanical polishing of indium arsenide single crystal substrate: The thinned substrate was fixed on a glass disk and then mechanically ground using a polishing machine. The abrasive used was alumina with a median particle size of 3 μm, and the pressure was 300 g / cm². 2 The rotation speed was 10 rpm, the flow rate of the alumina polishing solution was 18 mL / min, and after polishing for 15 minutes, the sample was removed, the sample surface was washed with ultrapure water, and then dried with a nitrogen gun.

[0033] S3, Chemical-mechanical polishing of indium arsenide single crystal substrate: The polished substrate was then subjected to chemical mechanical polishing (CMP) using a silica abrasive with a particle size of 80-120 nm. The CMP solution consisted of 5 vol% sodium hypochlorite, 30 vol% colloidal silica, and 65 vol% water. The CMP pressure was 300 g / cm³. 2 The grinding wheel speed was 50 rpm, the chemical mechanical polishing fluid flow rate was 5 mL / min, and after chemical mechanical polishing for 120 min, the sample was removed, the sample surface was cleaned with ultrapure water, and dried with a nitrogen gun.

[0034] S4, chemical polishing of indium arsenide single crystal substrate: The substrate is placed on a polishing device for chemical polishing. The polishing pad is a multi-layered, porous, high-surface-area composite polishing pad. The multi-layered structure of the composite polishing pad includes a substrate layer and a polishing layer. The substrate layer is further divided into a rigid substrate layer and an elastic substrate layer, providing stable support and appropriate elasticity for the polishing process. The polishing layers are a coarse polishing layer, a semi-fine polishing layer, and a fine polishing layer, each bonded by an elastic layer. The composite polishing pad has abundant pores of varying sizes, forming a gradient pore structure. The upper layer has large pores (200-500nm) for rapid liquid storage, while the lower layer has small pores (50-200nm) for uniform delivery of the polishing slurry, facilitating the storage, transport, and uniform distribution of the polishing slurry. The composite polishing pad has a high surface area, increasing the contact area with the polishing slurry and wafer through microstructures such as nanoscale pores (50-200nm diameter) and microgrooves (1-3μm depth, 5-10μm width). The chemical polishing pressure is 50-100 g / cm³. 2 The chemical polishing disc rotation speed is 15-25 rpm, the chemical polishing fluid flow rate is 1.5-3.0 mL / min, and the chemical polishing time is 15-20 min.

[0035] The chemical polishing solution was prepared as follows: 0.1 mol / L sodium hypochlorite 15 vol%, 30% hydrogen peroxide 40 vol%, 1 mol / L ammonium persulfate 10 vol%, and the remainder was water. The pH adjuster was lactic acid, a weak organic acid, resulting in a pH of 5.5. The polishing pressure was 100 g / cm³. 2 The grinding disc speed was 15 rpm, and the chemical polishing slurry flow rate was 3 mL / min. After chemical polishing for 10 min, the sample was removed, the sample surface was rinsed with ultrapure water, and then dried with a nitrogen gun.

[0036] S5, Cleaning of indium arsenide single crystal substrate: After chemical polishing, the substrate is immersed in alcohol at 60°C for 30 minutes to thoroughly remove residual polishing solution, etching agent and other impurities, ensuring that the substrate surface is clean.

[0037] S6, Drying of the indium arsenide single crystal substrate: The substrate, which had been soaked in alcohol, was subjected to mega-sonic cleaning at 5000 rpm for both cleaning and spin-drying. The ultrapure water cleaning time was 300 s, and the spin-drying time was 60 s. After completion, the sample was removed and placed in a sample box for later use.

[0038] Example 2 The S4 chemical polishing time in Example 2 was 20 min, and the other process parameters were exactly the same as in Example 1.

[0039] Example 3 The S4 chemical polishing time in Example 3 was 30 min, and the other process parameters were exactly the same as in Example 1.

[0040] Comparative Example 1 Comparative Example 1 did not undergo S4 chemical polishing, but all other process parameters were exactly the same as in Example 1, to illustrate the effect of chemical polishing on the removal of sub-damaged layers on indium arsenide single crystal substrates.

[0041] Special note: In this invention, the etching method reported in relevant literature is used to remove the sub-damaged layer of the indium arsenide substrate: the etching solution ratio is hydrochloric acid: hydrogen peroxide = 10:1 (volume ratio), and the etching time is 10 min.

[0042] Under the corrosive effects of the aforementioned liquid, sub-damage manifests as pits and scratches. The absence of pits and scratches indicates the absence of sub-damage (e.g., ...). Figure 3 (As shown).

[0043] Through the above specific implementation methods, the sub-damaged layer of indium arsenide single crystal substrate can be accurately removed, providing high-quality substrate materials for the manufacture of high-performance semiconductor devices.

[0044] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for finely controlling macroscopic and sub-damage on the surface of an indium arsenide substrate, characterized in that, Includes the following steps: S1, Substrate thinning, cutting the original indium arsenide substrate to the target thickness; S2, Mechanical polishing of the thinned substrate; S3, chemical mechanical polishing, wherein: Chemical mechanical polishing abrasives are one or more of silicon dioxide, diamond, magnesium oxide, and cerium oxide, with a particle size of 80-120 nm; Chemical mechanical polishing fluids contain colloidal abrasives; S4, chemical polishing A multi-layered, porous, high-surface-area composite polishing pad is employed. The pad comprises a substrate layer and a polishing layer. The substrate layer consists of a rigid substrate layer and an elastic substrate layer, providing stable support and appropriate elasticity for the polishing process. The polishing layer includes a coarse polishing layer, a semi-fine polishing layer, and a fine polishing layer, each bonded together by the elastic layer. The composite polishing pad has a gradient pore structure; the upper layer has large pores (200-500 nm) for rapid liquid storage, while the lower layer has small pores (50 nm) for transporting the polishing fluid. -200nm; the surface of the composite polishing pad also has a microgroove structure with a depth of 1-3μm and a width of 5-10μm, which can increase the contact area with the polishing slurry and wafer through nanoscale pores and microgrooves; the chemical polishing slurry is prepared as follows: 0.1mol / L sodium hypochlorite 15-20vol%, 30% hydrogen peroxide 30-40vol%, 1mol / L ammonium persulfate 10-15vol%, and the remainder is water; the pH is adjusted to 5-6 using lactic acid; the chemical polishing pressure is 50-100 g / cm², the chemical polishing disc speed is 15-25 rpm, the chemical polishing slurry flow rate is 1.5-3.0 mL / min, and the chemical polishing time is 15-20 min; S5, Cleaning; S6, dry.

2. The method for finely controlling macroscopic and sub-damage on the surface of an indium arsenide substrate according to claim 1, characterized in that, In step S1, a diamond grinding wheel is used for thinning. The diamond grinding wheel has a mesh size of 6000 or higher, a cutting rate of 1.0-3.0 μm / min, and a thinning thickness of ≥30 μm.

3. The method for finely controlling macroscopic and sub-damage on the surface of an indium arsenide substrate according to claim 1, characterized in that, In step S2, the abrasive used for mechanical grinding is one or more of the following: alumina, silicon carbide, and diamond abrasives with a D50 of 3µm to 5µm. The mechanical grinding pressure is 200-300 g / cm. 2 The mechanical grinding disc rotation speed is 5-15 rpm, the mechanical grinding fluid flow rate is 10-20 mL / min, and the time is 10-20 min.

4. The method for finely controlling macroscopic and sub-damage on the surface of an indium arsenide substrate according to claim 1, characterized in that, In step S3: The chemical mechanical polishing pressure is 300-350 g / cm². 2 The chemical mechanical polishing (CMP) grinding disc rotation speed is 35-50 rpm, the CMP slurry flow rate is 3-5 mL / min, and the time is 90-120 min.

5. The method for finely controlling macroscopic and sub-damage on the surface of an indium arsenide substrate according to claim 1, characterized in that, In step S5, the substrate is first sprayed with ultrapure water to prevent oxidation of the substrate surface and further remove residual particulate contaminants. Then, it is soaked and cleaned with an immersion solution to remove residual chemical polishing solution and impurities.

6. The method for finely controlling macroscopic and sub-damage on the surface of an indium arsenide substrate according to claim 5, characterized in that, Ultrapure water spraying time ≥180s; the soaking solution used for soaking and cleaning can be anhydrous ethanol, methanol, toluene, acetone organic solvents, soaking time ≥30min, soaking temperature 60-70℃.

7. A method for finely controlling macroscopic and sub-damage on the surface of an indium arsenide substrate according to any one of claims 1-6, characterized in that, In step S6, mega-sound rotary cleaning is used to further remove surface contaminants, and drying is performed by nitrogen blowing or centrifugal drying.

8. The method for finely controlling macroscopic and sub-damage on the surface of an indium arsenide substrate according to claim 7, characterized in that, When using nitrogen to dry, the nitrogen pressure should be ≤0.2 MPa and the temperature ≤35℃; when using centrifugal drying, the rotation speed should be 3000-5000 rpm and the drying time should be 30-60 s.

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