GaAs semiconductor etching method and semiconductor product
By combining low-concentration hydrogen fluoride aqueous solution and citric acid-hydrogen peroxide aqueous solution treatment with plasma bombardment, the problems of unstable corrosion rate and insufficient selectivity in GaAs semiconductor etching were solved, and the processing efficiency and yield were improved.
Patent Information
- Application Number
- CN202510606410.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-12
- Publication Date
- 2025-09-23
AI Technical Summary
Traditional GaAs semiconductor etching methods have problems such as unstable etching rate, insufficient selectivity for AlxGa-Asx/GaAs etching, and difficulty in controlling etching depth.
The etching process is optimized and the etching depth and selectivity are controlled by soaking in a low-concentration hydrogen fluoride aqueous solution combined with a specific ratio of citric acid-hydrogen peroxide aqueous solution and bombarding with oxygen-containing plasma.
The etching efficiency and yield rate are improved, the processing steps are simplified, the amount of chemical reagents used is reduced, and costs are saved.
Abstract
Description
Technical Field
[0001] The present application belongs to the field of semiconductor manufacturing technology, and specifically relates to a GaAs semiconductor etching method and a semiconductor product. Background Art
[0002] In the process of semiconductor manufacturing, the processing methods of semiconductor materials of different materials vary greatly. In the traditional GaAs processing method, the methods for wafer surface etching are mainly divided into wet etching and dry etching. Among them, wet etching has good controllability, fast etching speed and low cost, and is currently the main research direction.
[0003] In the traditional etching method of GaAs semiconductors, generally, the wafer surface is first subjected to plasma bombardment, followed by GaAs etching, and then the GaAs etching product is cleaned with ammonia dilution solution; the traditional wet etching method of GaAs semiconductors can be mainly divided into two categories. The first category uses ammonia and strong oxidant etching. This type of method has a faster etching rate and is more suitable for GaAs wafers with no bare feet on the surface. It is generally used for chemical polishing or arsenic and gallium recovery; the second category uses phosphoric acid compounds for etching. The advantage is that the etching rate is moderate and the restrictions on layout design are relatively small, but the disadvantage is that the etching stability is not high, and secondary etching is often required to achieve a more accurate etching depth, and the phosphoric acid solution does not have Al x Ga-As x / Selective etching of GaAs.
[0004] Therefore, it is necessary to develop a new etching method for GaAs semiconductors to solve the problems existing in traditional technical means. Summary of the Invention
[0005] The purpose of this application is to address the deficiencies of the prior art and provide a GaAs semiconductor etching method and semiconductor product, specifically adopting the following technical solutions:
[0006] First, the present application provides a GaAs semiconductor etching method, the steps comprising:
[0007] A GaAs wafer A that has completed the yellow light process is taken, and a first plasma bombardment is performed on wafer A to obtain wafer B; a first thickness measurement is performed on wafer B, and the measurement data is recorded at the same time. Subsequently, wafer B is immersed in a hydrogen fluoride aqueous solution with a mass concentration of 1% to 10% for 30 seconds to 60 seconds, and then a first cleaning is performed to obtain wafer C; wafer C is kept in a wet state and, within 1 minute to 5 minutes, wafer C is immersed in a citric acid-hydrogen peroxide aqueous solution for 15 seconds to 30 seconds, and then a second cleaning is performed to obtain wafer D; wafer D is dried, a second thickness measurement is performed on wafer D, and the measurement data is recorded at the same time. Subsequently, a second plasma bombardment is performed using an oxygen-containing plasma to obtain a GaAs semiconductor that has completed etching;
[0008] The data of the first thickness measurement and the data of the second thickness measurement are used to verify the etching depth;
[0009] The citric acid-hydrogen peroxide aqueous solution is prepared by mixing a 50% by mass concentration citric acid monohydrate aqueous solution and a 30% by mass concentration hydrogen peroxide aqueous solution in a volume ratio of (2.2-2.8): (0.7-1.3);
[0010] In the second plasma bombardment step, the chamber temperature is 65°C-75°C and the duration is 180s-300s.
[0011] In some specific embodiments, the first plasma bombardment step includes: performing plasma bombardment on wafer A using plasma containing oxygen.
[0012] In some specific embodiments, during the second plasma bombardment step, the chamber temperature is 70°C.
[0013] In some specific embodiments, the second plasma bombardment is performed within 120 minutes after the wafer D is obtained.
[0014] In some specific embodiments, the first washing step lasts for 3-5 minutes; the second washing step lasts for 3-5 minutes.
[0015] In some specific embodiments, the citric acid-hydrogen peroxide aqueous solution is prepared by mixing a 50% by mass citric acid monohydrate aqueous solution and a 30% by mass hydrogen peroxide aqueous solution in a volume ratio of 2.5:1.
[0016] In some specific embodiments, the concentration of the hydrogen fluoride aqueous solution is 1% by mass.
[0017] In some specific embodiments, the hydrogen fluoride aqueous solution is used at room temperature.
[0018] In some specific embodiments, the citric acid-hydrogen peroxide aqueous solution is used at room temperature.
[0019] Secondly, the present application also provides a semiconductor product produced using the above-mentioned GaAs semiconductor etching method during the processing process.
[0020] The beneficial effects of the present application are as follows: the present application combines a specific etching method, adopts a low-concentration hydrogen fluoride solution for immersion, and then transfers it to a low-concentration citric acid-hydrogen peroxide aqueous solution in a specific ratio in a very short time while maintaining a moist state, supplemented by a specific secondary plasma bombardment, further optimizing the processing path, improving processing efficiency, and improving processing yield, making the specific process simple, efficient and convenient. DETAILED DESCRIPTION
[0021] The following will be combined with the embodiments to clearly and completely describe the concept, specific structure and technical effects of this application so as to fully understand the purpose, scheme and effect of this application. It should be noted that the embodiments and features in the embodiments of this application can be combined with each other unless there is a conflict.
[0022] First, the present application provides a GaAs semiconductor etching method, the steps comprising:
[0023] A wafer A made of GaAs material that has completed a yellow light process is taken, and a first plasma bombardment is performed on wafer A to obtain wafer B; a first thickness measurement is performed on wafer B, and the measurement data is recorded at the same time; then wafer B is immersed in a hydrogen fluoride aqueous solution with a mass concentration of 1% to 10% for 30 seconds to 60 seconds, and then a first cleaning is performed to obtain wafer C; wafer C is kept in a wet state, and within 1 minute to 5 minutes, wafer C is immersed in a citric acid-hydrogen peroxide aqueous solution for 15 seconds to 30 seconds, and then a second cleaning is performed to obtain wafer D; wafer D is dried, a second thickness measurement is performed on wafer D, and the measurement data is recorded at the same time, and a second plasma bombardment is performed using an oxygen-containing plasma to obtain a GaAs semiconductor that has completed etching;
[0024] The data of the first thickness measurement and the data of the second thickness measurement are used to verify the etching depth;
[0025] The yellow light process mentioned in this application is also called "yellow light process" and refers to the lithography technology used in the semiconductor processing process. During lithography processing, the lighting environment in the processing workshop is yellow light, rather than the red light used in general photography darkrooms. Therefore, it is simply referred to as "yellow light processing" or "yellow light process";
[0026] In the present application, the etching method of GaAs semiconductor provided mainly refers to etching GaAs wafers; further, the etching method of GaAs semiconductor provided in the present application mainly targets etching GaAs wafers that have completed the yellow light process;
[0027] Therefore, a GaAs wafer A that has undergone the yellow light process is taken as the starting point of the specific embodiment of the etching method, and a first plasma bombardment process is performed to remove a trace amount of developer glue residue on the wafer surface caused by the yellow light process;
[0028] After the first plasma bombardment, wafer B is obtained and immersed in a 1% by mass hydrogen fluoride aqueous solution (in some other embodiments, the mass concentration of the hydrogen fluoride aqueous solution can be any value within the range of 1%-10%). This is to activate and remove some oxide residues on the surface of wafer B, facilitate precise control of impurities generated during subsequent processing, and thus optimize the production process.
[0029] Furthermore, in the present application, the concentration and processing time of the hydrogen fluoride aqueous solution must be precisely controlled so that the oxide layer on the surface of wafer B after plasma bombardment is properly activated. In this specific embodiment of the present application, wafer B is immersed in a hydrogen fluoride aqueous solution with a mass concentration of 1% (in some other specific embodiments, the mass concentration of the hydrogen fluoride aqueous solution can be any value in the range of 1%-10%) for 40 seconds (in some other specific embodiments, the immersion time can be any value in the range of 30 seconds-60 seconds); then it is rinsed with deionized water to obtain wafer C;
[0030] At this time, wafer C must be kept in deionized water to ensure that it is completely immersed in the deionized water. The wet wafer C should be transferred to the subsequent citric acid-hydrogen peroxide aqueous solution for processing within 1-5 minutes. During this process, wafer C should be kept from being exposed to air as much as possible, and the interval between wafer C and subsequent processing should be shortened as much as possible to allow wafer C to enter subsequent processing as soon as possible. This is to maintain the processing state of the wafer C surface and control impurities generated during the subsequent processing.
[0031] The citric acid-hydrogen peroxide aqueous solution is prepared by mixing a 50% by mass concentration citric acid monohydrate aqueous solution and a 30% by mass concentration hydrogen peroxide aqueous solution in a volume ratio of (2.2-2.8): (0.7-1.3);
[0032] The citric acid-hydrogen peroxide aqueous solution is prepared by a volume ratio of 2.5:1 of a 50% citric acid monohydrate aqueous solution and a 30% hydrogen peroxide aqueous solution (in some other specific embodiments, the volume ratio of the 50% citric acid monohydrate aqueous solution can be any value within the range of 2.2-2.8, and the volume ratio of the 30% hydrogen peroxide aqueous solution can be any value within the range of 0.7-1.3); wherein the citric acid monohydrate is also called "citric acid monohydrate" or "citric acid monohydrate".
[0033] The citric acid-hydrogen peroxide aqueous solution configured in the present application is different from that in the prior art. The citric acid-hydrogen peroxide aqueous solution used in the present application is prepared in a specific ratio and coordinated with the previous steps, so that after the wafer C is etched with the specific citric acid-hydrogen peroxide aqueous solution provided in the present application, the composition of the chemical substances to be removed generated is more controllable and easier to remove through specific subsequent technical means.
[0034] Of particular importance is that, in the present application, wafer C is immersed in the citric acid-hydrogen peroxide aqueous solution for 25 seconds (in some other specific embodiments, the immersion time is any value within the range of 15 seconds to 30 seconds). By immersing for a specific time, the degree of etching of wafer C by the citric acid-hydrogen peroxide aqueous solution can be more accurately controlled, while the composition of the chemical substances formed can also be strictly controlled.
[0035] It is important to emphasize again that in the GaAs semiconductor etching method provided in the present application, after wafer B is soaked in a 1% concentration hydrogen fluoride aqueous solution and cleaned, it must be kept in a wet state, preferably immersed in deionized water, and subsequently soaked in a citric acid-hydrogen peroxide aqueous solution within 1 minute to 5 minutes. During the above process, if wafer B is removed from the wet state at any time, the selectivity of the subsequent processing process will be destroyed, resulting in the inability to proceed with the subsequent part of the specific GaAs semiconductor etching method provided in the present application.
[0036] In the second plasma bombardment step, the chamber temperature is 65°C-75°C and the duration is 180s-300s.
[0037] After the wafer C is immersed in the citric acid-hydrogen peroxide solution, a second cleaning step is required to wash away the residual citric acid-hydrogen peroxide solution. At this time, the wafer D is obtained, and the wafer D can now be freed from the wet state.
[0038] The wafer D is fully dried. In this specific embodiment of the present application, the wafer D is dried by selective drying in a nitrogen environment. At this time, the thickness of the wafer D needs to be measured for the second time, and the measurement data is recorded.
[0039] Subsequently, wafer D is subjected to a second plasma bombardment using plasma containing oxygen to remove the chemical substances to be removed generated in the previous step, thereby obtaining a GaAs semiconductor that has been completely etched. The GaAs semiconductor is the GaAs wafer that has been completely etched.
[0040] It must be emphasized that in the second plasma bombardment step, the chamber temperature is 70°C (in some other specific implementations, it can be any value in the range of 65°C-75°C), the duration is 220s (in some other specific implementations, it can be any value in the range of 180s-300s); the difference between the data obtained by the first thickness measurement and the data obtained by the second thickness measurement is the etching depth of this etching process.
[0041] In some specific embodiments, the first plasma bombardment step includes: using oxygen-containing plasma to perform plasma bombardment on wafer A; using oxygen-containing plasma to perform plasma bombardment on wafer A can effectively remove residual chemicals in the yellow light process.
[0042] In some specific embodiments, during the second plasma bombardment step, the chamber temperature is 70°C; the preferred temperature for the second plasma bombardment is 70°C. Performing the second plasma bombardment at this temperature has the best effect on the chemical substances to be removed generated in the GaAs semiconductor etching method provided in this application.
[0043] In some specific embodiments, a second plasma bombardment is performed within 120 minutes after wafer D is obtained; since wafer D has completed the previous citric acid-hydrogen peroxide aqueous solution reaction, wafer D can now be out of a wet state, shortening the interval for processing wafer D, which can effectively improve the effect of the second plasma bombardment and avoid the generation of unnecessary oxide impurities on the surface of wafer D due to long-term exposure.
[0044] In some specific embodiments, the first washing step lasts for 3-5 minutes; the second washing step lasts for 3-5 minutes.
[0045] Preferably, the citric acid-hydrogen peroxide aqueous solution is prepared by mixing a 50% by mass citric acid monohydrate aqueous solution and a 30% by mass hydrogen peroxide aqueous solution in a volume ratio of 2.5:1. The citric acid-hydrogen peroxide aqueous solution in a specific ratio can bring about a relatively excellent processing effect.
[0046] In some specific embodiments, the concentration of the hydrogen fluoride aqueous solution is 1% by mass concentration. The etching method for GaAs semiconductors provided in the present application overcomes the high-concentration hydrofluoric acid etching existing in traditional technologies and optimizes the entire process in a targeted manner, so that the chemical substances to be removed can be removed by a specific second plasma bombardment, which greatly optimizes the various technical limitations existing in traditional GaAs semiconductor etching, improves efficiency, reduces the amount of chemical reagents used, and saves costs.
[0047] In some specific embodiments, the temperature of the hydrogen fluoride aqueous solution is room temperature; in the specific GaAs semiconductor etching method provided in the present application, the use of the hydrogen fluoride aqueous solution can be carried out at room temperature under normal conditions, which relaxes the processing conditions, simplifies the processing steps, and overcomes the temperature limitations in traditional processing technology.
[0048] In some specific embodiments, the temperature of using the citric acid-hydrogen peroxide aqueous solution is room temperature; in the specific GaAs semiconductor etching method provided in the present application, the use of the citric acid-hydrogen peroxide aqueous solution can be carried out at room temperature under normal conditions, which relaxes the processing conditions, simplifies the processing steps, and overcomes the temperature limitations in traditional processing technology.
[0049] Secondly, the present application also provides a semiconductor product produced using the above-mentioned GaAs semiconductor etching method during the processing process.
[0050] Although the description of the present application has been quite detailed and particularly describes the embodiments, it is not intended to be limited to any of these details or embodiments or any particular embodiment, but should be regarded as providing a broad possible interpretation of these claims in view of the prior art by reference to the appended claims, thereby effectively covering the intended scope of the present application. In addition, the above description of the present application is based on the embodiments foreseeable by the applicant, which is intended to provide a useful description, and those non-substantial changes to the present application that have not yet been foreseen may still represent equivalent changes to the present application.
Claims
1. A method for etching a GaAs semiconductor, characterized in that the steps include: Wafer A made of GaAs material that has completed the yellow light process is taken and subjected to a first plasma bombardment on the wafer A to obtain wafer B; then, the wafer B is immersed in a hydrogen fluoride aqueous solution with a mass concentration of 1% to 10% for 30s to 60s, and then subjected to a first cleaning to obtain wafer C; Keeping wafer C in a wet state, and immersing the wafer C in a citric acid-hydrogen peroxide aqueous solution for 15 seconds to 30 seconds within 1 minute to 5 minutes, followed by a second cleaning to obtain wafer D; drying the wafer D, and then performing a second plasma bombardment using an oxygen-containing plasma to obtain a GaAs semiconductor that has been completely etched; The citric acid-hydrogen peroxide aqueous solution is prepared by mixing a 50% citric acid monohydrate aqueous solution and a 30% hydrogen peroxide aqueous solution in a volume ratio of (2.2-2.8): (0.7-1.3); In the second plasma bombardment step, the chamber temperature is 65° C.-75° C., and the duration is 180 s-300 s.
2. The etching method for a GaAs semiconductor according to claim 1, wherein: The first plasma bombardment step includes: performing plasma bombardment on the wafer A using plasma containing oxygen.
3. The etching method for a GaAs semiconductor according to claim 1, wherein: During the second plasma bombardment step, the chamber temperature is 70°C.
4. The etching method for a GaAs semiconductor according to claim 3, characterized in that: The second plasma bombardment was performed within 120 minutes after the wafer D was obtained.
5. The etching method for a GaAs semiconductor according to claim 1, wherein: The first cleaning step lasts for 3-5 minutes; and / or the second cleaning step lasts for 3-5 minutes.
6. The etching method for a GaAs semiconductor according to claim 1, characterized in that: The citric acid-hydrogen peroxide aqueous solution is prepared by mixing a citric acid monohydrate aqueous solution with a mass concentration of 50% and a hydrogen peroxide aqueous solution with a mass concentration of 30% in a volume ratio of 2.5:
1.
7. The etching method for a GaAs semiconductor according to claim 1, characterized in that: The mass concentration of the hydrogen fluoride aqueous solution is 1%.
8. The etching method for a GaAs semiconductor according to claim 1, wherein: The operating temperature of the hydrogen fluoride aqueous solution is room temperature.
9. The etching method for a GaAs semiconductor according to claim 1, wherein: The operating temperature of the citric acid-hydrogen peroxide aqueous solution is room temperature.
10. A semiconductor product, characterized in that The preparation process includes the GaAs semiconductor etching method according to any one of claims 1 to 9.