Roughening liquid for semiconductor material as well as preparation method and application of roughening liquid

Abstract

The invention provides coarsening liquid for a semiconductor material and a preparation method and application of the coarsening liquid, and belongs to the technical field of semiconductor material processing. The roughening liquid comprises the following components in percentage by mass: 5-30% of inorganic acid, 5-10% of organic acid, 2-5% of an amino complexing agent, 0.5-5% of an oxidizing agent, 0.05-0.5% of a functional additive and the balance of water, the functional additive comprises one or two of polyethylene maleic anhydride and carboxyl modified polyvinyl alcohol. The coarsening liquid is used for surface processing of III-V group semiconductor materials, and the problems that due to the coarsening time difference, surface corrosion is uneven, and water mark-shaped poor appearance is presented can be solved. The roughening liquid is used in the field of semiconductor materials, is suitable for current production equipment and process, and is reliable and effective in scheme.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material processing technology, and in particular to a roughening liquid for semiconductor materials, its preparation method, and its application. Background Technology

[0002] The roughening solution forms a micro-rough structure on the surface of III-V semiconductor materials such as AlGaInP through chemical wet etching, which reduces total internal reflection and improves light extraction efficiency. It is widely used in industries such as red / yellow LEDs, laser diodes and semiconductor chips.

[0003] In the semiconductor manufacturing field, roughening solutions are already widely sold and used. Currently, existing roughening solutions are typically high-concentration acidic salt solutions, composed of organic acids, inorganic acids, and amine / ammonium compounds. Adding oxidants and corresponding stabilizers to the roughening solution can improve the roughening rate. Patent CN 112680227 A adds a highly stable and low-surface-tension perfluorinated surfactant; patent CN 116333745 A adds a nonionic surfactant (fatty alcohol / alkylphenol polyether); and patent CN 116875316 A adds anionic surfactants such as alkyl ammonium bromide and / or sodium alkyl sulfonate. The addition of these wetting agents reduces the interfacial tension of the roughening interface, allowing for more thorough contact between the roughening solution and the interface to be roughened. This facilitates the rapid departure of reaction products and bubbles from the reaction interface, promoting a more regular and uniform roughened interface.

[0004] The roughening solution is a highly concentrated acidic solution. Immersing the semiconductor chip to be roughened vertically in it at room temperature for 60-90 seconds achieves the desired roughening effect. After roughening, the semiconductor chip is removed from the roughening solution and left to rinse in a pure water bath for 20-30 seconds. This allows the roughening solution to flow back into the bath, reducing entrainment and minimizing process losses. As the roughening solution flows from the top to the bottom of the chip surface, the difference in contact time between the solution and the surface can easily lead to uneven surface corrosion, resulting in watermark-like defects. In particular, the aforementioned patent's approach of reducing surface tension makes it easier for the roughening solution to spread and remain on the chip surface, exacerbating the watermark-like defects. Summary of the Invention

[0005] The purpose of this invention is to provide a roughening solution for semiconductor materials, its preparation method and application, to solve the problem of abnormal watermark appearance in the actual processing of existing roughening solutions, and to improve the stability of the roughening process and the product yield.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a roughening liquid for semiconductor materials, comprising the following components in weight percentage: Inorganic acid 5-30%, organic acid 5-10%, amino complexing agent 2-5%, oxidizing agent 0.5-5%, functional additives 0.05-0.5%, balance water; The functional additives include one or both of polyvinyl maleic anhydride and carboxyl-modified polyvinyl alcohol.

[0007] Preferably, the inorganic acid includes one or more of hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, and fluorosilicic acid.

[0008] Preferably, the organic acid includes one or more of formic acid, acetic acid, malonic acid, oxalic acid, tartaric acid, succinic acid, citric acid, gluconic acid, methanesulfonic acid, p-toluenesulfonic acid, aminosulfonic acid, benzoic acid, and phthalic acid.

[0009] Preferably, the amino complexing agent includes one or more of alanine, leucine, glycine, aspartic acid, glutamic acid, serine, histidine, and ethylenediaminetetraacetic acid.

[0010] Preferably, the oxidant includes one or more of nitric acid, potassium periodate, perchloric acid, sodium hypochlorite, and potassium permanganate.

[0011] Preferably, the molecular weight of the polyethylene maleic anhydride is 3,000 to 100,000.

[0012] Preferably, the functional additive further includes a wetting agent, which includes alkylphenol polyoxyethylene ether.

[0013] This invention provides a method for preparing the roughening liquid for semiconductor materials as described in the above technical solution, comprising the following steps: Under continuous nitrogen purging, inorganic acid, organic acid, amino complexing agent, functional additive and oxidant are added to water in sequence. The resulting mixture is filtered to obtain a roughening solution for semiconductor materials.

[0014] Preferably, the water is pure water with a resistivity ≥18 MΩ·cm; the nitrogen gas has a purity of 99.9%. The time intervals between the sequential addition of inorganic acid, organic acid, amino complexing agent, functional additive and oxidant are 10-30 min; the filtration accuracy is 0.1-0.5 μm.

[0015] This invention provides the application of the roughening liquid for semiconductor materials described in the above technical solution or the roughening liquid for semiconductor materials prepared by the preparation method described in the above technical solution in the semiconductor field.

[0016] This invention provides a roughening solution for semiconductor materials comprising the following components by mass percentage: 5-30% inorganic acid, 5-10% organic acid, 2-5% amino complexing agent, 0.5-5% oxidant, 0.05-0.5% functional additive, and the balance being water; the functional additive includes one or both of polyvinyl maleic anhydride and carboxyl-modified polyvinyl alcohol. The carboxyl-modified polyvinyl alcohol has a molecular structure with continuously arranged branched carboxyl groups and branched hydroxyl groups; the polyvinyl maleic anhydride, due to anhydride hydrolysis, exhibits a long carbon chain molecular structure with adjacent carboxyl branches. The carboxyl groups in the functional additive used in this invention partially adsorb onto highly active sites on the newly roughened surface, protecting the already roughened area while the branched carboxyl and carbonyl groups accelerate the transfer of corroded metal ions from the roughened surface to the bulk solution, reducing the metal ion concentration gradient at the roughened area interface, reducing metal precipitate deposition, and promoting roughening of surrounding sites. The carboxyl groups in the functional additive continue to adsorb newly formed highly active sites. As highly active adsorption sites accumulate, the functional additives adhere to the roughened surface, forming a molecular adsorption layer. This restricts direct contact between the roughening solution and the roughened interface, preventing the spreading and retention of the roughening solution on the roughened surface during subsequent drying processes. This avoids watermark-like defects caused by differences in contact time. Using the roughening solution described in this invention for surface processing of III-V group semiconductor materials can solve the problem of uneven surface corrosion and watermark-like defects caused by differences in roughening time.

[0017] The roughening solution of this invention is used in the field of semiconductor materials, is suitable for current production equipment and processes, and the solution is reliable and effective. Attached Figure Description

[0018] Figure 1 Images showing the effect of roughening the chip using the roughening solution in Example 4; Figure 2 The image shows the effect of roughening the chip using the roughening solution in Comparative Example 1. Detailed Implementation

[0019] In this invention, unless otherwise specified, the raw materials or reagents required for preparation are all commercially available products well known to those skilled in the art, and preferably of analytical grade or higher.

[0020] This invention provides a roughening liquid for semiconductor materials, comprising the following components in weight percentage: Inorganic acid 5-30%, organic acid 5-10%, amino complexing agent 2-5%, oxidizing agent 0.5-5%, functional additives 0.05-0.5%, balance water; The functional additives include one or both of polyvinyl maleic anhydride and carboxyl-modified polyvinyl alcohol.

[0021] The roughening solution for semiconductor materials provided by the present invention comprises 5-30% inorganic acid, preferably 10-25%, more preferably 15-22%, and even more preferably 16-20%, by mass percentage.

[0022] In this invention, the inorganic acid preferably includes one or more of hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, and fluorosilicic acid. When the inorganic acid is two or more of the above, this invention does not have a special limitation on the ratio of different types of inorganic acids, and any ratio is acceptable. This invention does not have a special limitation on the concentration or specification of the inorganic acid, and commercially available products well known in the art are acceptable.

[0023] The roughening solution for semiconductor materials provided by the present invention comprises 5-10% organic acid, preferably 6-9%, and more preferably 7-8%, by mass percentage.

[0024] In this invention, the organic acid preferably includes one or more of formic acid, acetic acid, malonic acid, oxalic acid, tartaric acid, succinic acid, citric acid, gluconic acid, methanesulfonic acid, p-toluenesulfonic acid, aminosulfonic acid, benzoic acid, and phthalic acid. When the organic acid is two or more of the above, this invention does not have a special limitation on the ratio of different types of organic acids, and any ratio is acceptable. This invention does not have a special limitation on the specific concentration or specification of the organic acid; commercially available products well known in the art are acceptable.

[0025] This invention uses a combination of organic and inorganic acids to provide a roughened acidic etching environment, with the organic acid in particular providing an acid stability window.

[0026] The roughening liquid for semiconductor materials provided by the present invention comprises 2-5% amino complexing agent, more preferably 2.5-4.5%, and even more preferably 3-4%, by mass percentage.

[0027] In this invention, the amino complexing agent preferably includes one or more of alanine, leucine, glycine, aspartic acid, glutamic acid, serine, histidine, and ethylenediaminetetraacetic acid. When the amino complexing agent is two or more of the above, this invention does not have a special limitation on the ratio of different types of amino complexing agents, and any ratio is acceptable. In this invention, the amino complexing agent can bind to metal ions dissolved in the roughening solution due to corrosion, reduce the concentration of free metal ions in the roughening solution, stabilize the roughening effect, and extend the life of the roughening solution.

[0028] The roughening solution for semiconductor materials provided by the present invention comprises 0.5-5% oxidant, more preferably 1-4%, and even more preferably 2-3% by mass percentage.

[0029] In this invention, the oxidant preferably includes one or more of nitric acid, potassium periodate, perchloric acid, sodium hypochlorite, and potassium permanganate. When the oxidant is two or more of the above, this invention does not have a special limitation on the ratio of different types of oxidants, and any ratio is acceptable. In this invention, the oxidant acts as a roughening promoter, which is beneficial to improving roughening efficiency.

[0030] The roughening liquid for semiconductor materials provided by the present invention comprises 0.05-0.5% functional additives, preferably 0.1-0.4%, more preferably 0.2-0.35%, and even more preferably 0.25-0.3% by mass percentage.

[0031] In this invention, the functional additives include one or both of polyethylene maleic anhydride and carboxyl-modified polyvinyl alcohol; the functional additives preferably also include a wetting agent, which preferably includes alkylphenol polyoxyethylene ether. When the functional additives are two or more of the above, this invention does not have a special limitation on their ratio, and any ratio is acceptable.

[0032] In this invention, the molecular weight of the polyethylene maleic anhydride is preferably 3,000 to 100,000.

[0033] In this invention, the polyethylene maleic anhydride is an ethylene-maleic anhydride copolymer ZeMac (an alternating copolymer of ethylene and maleic anhydride in a 1:1 ratio (wherein the mass ratio: ethylene < 22%, maleic anhydride > 78%)), which is sourced from Shanghai Nasu Alloy Technology Co., Ltd.

[0034] In this invention, the carboxyl-modified polyvinyl alcohol is preferably Kuraray-modified polyvinyl alcohol POVAL 25-88KL.

[0035] After the semiconductor material is roughened using the roughening solution of the present invention, the functional additives can be adsorbed onto the highly active sites on the newly roughened surface. The polycarboxyl functional groups in the additives can accelerate the conduction of corroded metal ions into the bulk solution, reduce the metal ion concentration gradient at the interface, and reduce the roughening defects caused by metal precipitates. In addition, the functional additives can limit the direct contact between the roughening solution and the roughened interface, and prevent the roughening solution from spreading and staying on the roughened surface during the subsequent drying process, thus avoiding watermark-like appearance defects caused by differences in contact time.

[0036] This invention provides a method for preparing the roughening liquid for semiconductor materials as described in the above technical solution, comprising the following steps: Under continuous nitrogen purging, inorganic acid, organic acid, amino complexing agent, functional additive and oxidant are added to water in sequence. The resulting mixture is filtered to obtain a roughening solution for semiconductor materials.

[0037] In this invention, the water is preferably pure water with a resistivity ≥18 MΩ·cm; the purity of the nitrogen is preferably 99.9%.

[0038] In this invention, the time interval between sequentially adding inorganic acid, organic acid, amino complexing agent, functional additive and oxidant is preferably 10-30 min, more preferably 10-20 min; the filtration accuracy is preferably 0.1-0.5 μm, more preferably 0.1-0.3 μm.

[0039] In this invention, the roughening liquid is preferably prepared by physical stirring at room temperature and pressure; the stirring speed is preferably 50~200 r / min, more preferably 100~150 r / min, to achieve uniform mixing.

[0040] In this invention, the preparation method of the roughening liquid is more preferably as follows: In a Class 1000 cleanroom, pure water is added to a polytetrafluoroethylene-lined stirred tank, and stirring is started; every 10 minutes, inorganic acid, organic acid, amino complexing agent, functional additive, and oxidant are added sequentially to the pure water, mixed evenly, and then filtered to obtain the roughening liquid. Throughout the entire process from stirring and mixing to filtration, 99.9% pure nitrogen gas is continuously introduced into the stirred tank to remove air and provide a positive pressure environment inside the stirred tank, preventing impurities such as particles in the outside air from invading and causing liquid contamination.

[0041] The present invention does not impose any special limitation on the components used for filtration; any component with the aforementioned filtration precision that is well known in the art can be used.

[0042] This invention provides the application of the roughening liquid for semiconductor materials described in the above-described technical solutions, or the roughening liquid for semiconductor materials prepared by the preparation method described in the above-described technical solutions, in the semiconductor field. This invention does not specifically limit the method of application; any method well-known in the art can be used.

[0043] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0044] Unless otherwise specified, the experimental methods described in the various embodiments of this invention are conventional methods; unless otherwise specified, the reagents and raw materials described below are all commercially available analytical grade.

[0045] In the following examples, the functional additive, polyethylene maleic anhydride, is ethylene maleic anhydride copolymer ZeMac E10, sourced from Shanghai Nasu Alloy Technology Co., Ltd. The carboxyl-modified polyvinyl alcohol is derived from Kuraray's modified polyvinyl alcohol POVAL 25-88KL from Japan.

[0046] Example 1

[0047] The components of the roughening liquid provided in this embodiment, by mass percentage, Inorganic acids: 2% hydrochloric acid (Shanghai testing brand, content 36~38%), 3% hydrofluoric acid (Shanghai testing brand, content 40%); Organic acids: Acetic acid (Guangzhou Chemical Reagent Factory, 99.5% purity) 7.5%, tartaric acid (Shanghai Test brand, 99.5% purity) 1.5%, benzoic acid (Shanghai Test brand, 99.5% purity) 1%; Amino complexing agents: 2% alanine (BR grade, Shanghai testing brand, 98.5% purity), 2% aspartic acid (BR grade, Shanghai testing brand, 99% purity); Oxidizing agent: 3% nitric acid (Shanghai testing brand, content 65~68%); Functional additive: ZeMac E10 0.25%; Pure water balance.

[0048] The preparation method of the roughening solution is as follows: Under normal temperature and pressure, in a Class 1000 cleanroom, nitrogen gas with a purity of 99.9% is continuously introduced into a stirred tank lined with polytetrafluoroethylene, the stirring speed is 100 r / min, and pure water with a resistivity of 18 MΩ·cm is added; every 10 min, inorganic acid, organic acid, amino complexing agent, functional additive and oxidant are added in sequence; after mixing evenly, the mixture is filtered using a filter bag with a precision of 0.1 μm to obtain the roughening solution.

[0049] Example 2

[0050] The components of the roughening liquid provided in this embodiment, by mass percentage, Inorganic acids: 1% phosphoric acid (Shanghai testing brand, 85% purity), 15% hydrofluoric acid; Organic acids: Formic acid (Guangzhou Chemical Reagent Factory, 88% purity) 2%, gluconic acid (Xingzhou Pharmaceutical Industrial Grade, 50% purity) 3%, phthalic acid (Shanghai Test Brand, 99.8% purity) 1%; Amino complexing agents: 1% glutamic acid (Shanghai testing brand, 98% purity), 1% leucine (Wuxi Jinghai industrial grade, 98.5% purity); Oxidizing agents: Potassium permanganate (Shanghai testing brand, 99.5% purity) 4.5%, perchloric acid (Shanghai testing brand, 70% purity) 0.5%; Functional additives: ZeMac E10 0.2%, POVAL 25-88KL 0.05%; Pure water balance.

[0051] The preparation method is the same as in Example 1.

[0052] Example 3

[0053] The components of the roughening liquid provided in this embodiment, by mass percentage, Inorganic acids: 20% sulfuric acid (Shanghai Test brand, 95-98% purity), 5% fluorosilicic acid (Guangzhou Chemical Reagent Factory, 30% purity); Organic acids: Methanesulfonic acid (BASF industrial grade, 99% purity) 2%, oxalic acid (Shanghai Test brand, 99.5% purity) 2%, malonic acid (Suqian Nanxiang electronic grade, 99.7% purity) 1%; Amino complexing agents: 3% ethylenediaminetetraacetic acid (Wuxi Jinghai industrial grade, 99% purity), 2% serine (Wuxi Jinghai industrial grade, 98% purity); Oxidizing agent: Potassium periodate 4%; Functional additives: ZeMac E10 0.4%, POVAL 25-88KL 0.1%; Pure water balance.

[0054] The preparation method is the same as in Example 1.

[0055] Example 4

[0056] The components of the roughening liquid provided in this embodiment, by mass percentage, Inorganic acids: Phosphoric acid (Shanghai test brand, content 85%) 28%, fluorosilicic acid 2%; Organic acids: citric acid (Shandong Yingxuan industrial grade, 99.5% purity) 3%, p-toluenesulfonic acid (Shandong Jichuang refined grade, 99% purity) 3%, aminosulfonic acid 2%; Amino complexing agents: Histidine (Wuxi Jinghai industrial grade, 99% purity) 1%, glycine (Shanghai testing brand, 99.5% purity) 1.5%; Oxidizing agent: Sodium hypochlorite (Guangzhou Chemical Reagent Factory, content 7.5%) 0.5%; Functional additives: ZeMac E10 0.1%, POVAL 25-88KL 0.2%, Alkylphenol polyoxyethylene ether Triton X100 0.2%; Pure water balance.

[0057] The preparation method is the same as in Example 1.

[0058] Comparative Example 1

[0059] The only difference from Example 4 is that: In the roughening solution provided in this comparative example, the functional additive is only 0.3% of alkylphenol polyoxyethylene ether Triton X100; the other components are the same as in Example 4.

[0060] Comparative Example 2 (compared to Example 2)

[0061] The components of the roughening solution provided in this comparative example are as follows: by mass percentage. Inorganic acids: 1% phosphoric acid, 15% hydrofluoric acid; Organic acids: formic acid 2%, gluconic acid 3%, phthalic acid 1%; Amino complexing agents: 1% glutamic acid, 1% leucine; Oxidizing agents: 4.5% potassium permanganate, 0.5% perchloric acid; Functional additives: None; Pure water balance.

[0062] The preparation method is the same as in Example 1.

[0063] Performance testing

[0064] Testing method for the roughening solution: Under normal pressure and at 24℃, the AlGaInP LED semiconductor chip to be processed was sequentially immersed in roughening solution tanks prepared in different cases, with nitrogen gas bubbled through the tanks. The immersion time in each tank was 30 seconds. After the chip was removed from the roughening tank and drained for 30 seconds, it was rinsed in a pure water tank and then dried with hot nitrogen gas at 70℃. The appearance of the chip was observed visually. The results are shown in [see attached image]. Figures 1-2 See Table 1.

[0065] Figure 1 The image shows the effect of roughening the chip using the roughening solution in Example 4. It can be seen that when the wetting agent alkylphenol polyoxyethylene ether is added, no watermarks or defects are observed on the surface of the material processed using the roughening solution in Example 4, and there are basically no watermarks.

[0066] Figure 2 The image shows the effect of roughening the chip with the roughening solution in Comparative Example 1. After treatment with the roughening solution in Comparative Example 1, the chip surface has an uneven appearance and shows watermarks.

[0067] Table 1. Results of watermarks on chips after roughening solution treatment in Examples 1-4 and Comparative Examples 1-2.

[0068] From Table 1 and Figures 1-2 It is understood that the roughening liquid of the present invention can solve the problem of uneven roughening surface and watermarks, making it more suitable for stable production and improving product yield.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A roughening liquid for semiconductor materials, characterized in that, The components include the following components by mass percentage: Inorganic acid 5-30%, organic acid 5-10%, amino complexing agent 2-5%, oxidizing agent 0.5-5%, functional additives 0.05-0.5%, balance water; The functional additives include one or both of polyvinyl maleic anhydride and carboxyl-modified polyvinyl alcohol.

2. The roughening liquid according to claim 1, characterized in that, The inorganic acids include one or more of hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, and fluorosilicic acid.

3. The roughening liquid according to claim 1, characterized in that, The organic acids include one or more of formic acid, acetic acid, malonic acid, oxalic acid, tartaric acid, succinic acid, citric acid, gluconic acid, methanesulfonic acid, p-toluenesulfonic acid, aminosulfonic acid, benzoic acid, and phthalic acid.

4. The roughening liquid according to claim 1, characterized in that, The amino complexing agent includes one or more of alanine, leucine, glycine, aspartic acid, glutamic acid, serine, histidine, and ethylenediaminetetraacetic acid.

5. The roughening liquid according to claim 1, characterized in that, The oxidizing agent includes one or more of nitric acid, potassium periodate, perchloric acid, sodium hypochlorite, and potassium permanganate.

6. The roughening liquid according to claim 1, characterized in that, The molecular weight of the polyethylene maleic anhydride is 3000~100000.

7. The roughening liquid according to claim 1, characterized in that, The functional additives also include wetting agents, which include alkylphenol polyoxyethylene ethers.

8. The method for preparing the roughening solution for semiconductor materials according to any one of claims 1 to 7, characterized in that, Includes the following steps: Under continuous nitrogen purging, inorganic acid, organic acid, amino complexing agent, functional additive and oxidant are added to water in sequence. The resulting mixture is filtered to obtain a roughening solution for semiconductor materials.

9. The preparation method according to claim 8, characterized in that, The water is pure water with a resistivity ≥18 MΩ·cm; the nitrogen gas has a purity of 99.9%. The time intervals between the sequential addition of inorganic acid, organic acid, amino complexing agent, functional additive and oxidant are 10-30 min; the filtration accuracy is 0.1-0.5 μm.

10. The application of the roughening liquid for semiconductor materials according to any one of claims 1 to 7 or the roughening liquid for semiconductor materials prepared by the preparation method according to any one of claims 8 to 9 in the semiconductor field.

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