A method for etching and pre-cleaning micropores of semiconductor silicon electrodes

Abstract

This invention discloses a pre-cleaning method for etching micropores of semiconductor silicon electrodes, comprising the following steps: 1) immersing the silicon electrode to be cleaned in an alkaline degreasing solution; 2) rinsing the micropores of the silicon electrode with pure water; 3) immersing the rinsed silicon electrode in pure water for ultrasonic cleaning; and 4) immersing the treated silicon electrode in a hydrogen peroxide solution. This invention effectively removes surface particles and contaminants from the silicon electrode surface by immersing it in an alkaline degreasing solution, rinsing it with pure water, and ultrasonic cleaning. Finally, immersing the silicon electrode in a hydrogen peroxide solution allows the hydrogen peroxide solution to release oxygen in the alkaline solution. This released oxygen can penetrate into the micropores of the silicon electrode with a diameter of 0.2-0.5 mm, rapidly and effectively oxidizing contaminants inside the micropores. This ensures a uniform reaction during subsequent etching, achieving consistent etching conditions inside and outside the pores and preventing trailing color differences.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor fabrication technology, and specifically relates to an etching pre-cleaning method for micropores in semiconductor silicon electrodes. Background Technology

[0002] As semiconductor devices become increasingly integrated, silicon electrode microvias, as a key structure for vertical interconnects between chip layers, typically have a diameter of ≤0.5mm and can number in the thousands. Their processing quality directly impacts the electrical performance of the devices. Before the etching process, a pre-cleaning step must thoroughly remove contaminants from the surface and within the microvias to avoid defects such as sidewall roughness, critical dimension deviations, and uneven reactions during subsequent etching.

[0003] Currently, the industrial sector commonly uses ultrasonic-assisted degreasing cleaning, controlling the temperature at 45-50℃. This method utilizes ultrasonic cavitation to remove surface particles, resulting in a more uniform subsequent etching reaction. While effective for conventional structures, this method is ineffective against high-density fine pores with diameters of 0.2mm-0.5mm. The degreasing solution is hindered by surface tension, making it difficult to penetrate to the bottom of the pore. Furthermore, the ultrasonic energy attenuates rapidly within the narrow pores, resulting in extremely weak cleaning ability on the inner walls and rendering it completely ineffective in treating the inner surface.

[0004] Furthermore, incomplete pre-cleaning directly leads to serious quality problems in subsequent etching processes: for example, residual contaminants on the inner walls of micropores cause uneven etching reaction rates, significant differences in etching degree between the orifice and the bottom, and obvious trailing color differences on the surface of the micropores, ultimately resulting in uneven etching across the entire product surface. This defect not only damages the uniformity of appearance but also causes electrical performance problems such as fluctuations in contact resistance and increased leakage current, significantly reducing product yield. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the main objective of this invention is to provide an etching pre-cleaning method for semiconductor silicon electrode micropores that can overcome micropore penetration barriers and effectively clean the inner walls of 0.2mm-0.5mm fine pores.

[0006] The objective of this invention is achieved through the following technical solution: A method for etching and pre-cleaning micropores of semiconductor silicon electrodes, comprising the following steps: 1) Immerse the silicon electrode to be cleaned in an alkaline degreasing solution; 2) Rinse the small holes of the silicon electrode after step 1) with pure water; 3) Immerse the silicon electrode rinsed in step 2) in pure water for ultrasonic cleaning; 4) Immerse the silicon electrode treated in step 3) in hydrogen peroxide solution.

[0007] In some specific embodiments, the soaking process conditions in step 1) are soaking in an alkaline degreasing solution at 40-50°C for 5-10 minutes.

[0008] In some specific embodiments, the silicon electrode described in step 1) has a diameter of 320 mm, a thickness of 25 mm, and a pore size of ≤0.5 mm.

[0009] Furthermore, the pore size of the silicon electrode mentioned in step 1) is 0.2-0.5 mm.

[0010] In some specific embodiments, the ultrasonic cleaning process conditions in step 3) are: ultrasonic treatment for 5-15 minutes at a current of 2.0-3.0A and a frequency of 30-50Hz.

[0011] In some specific embodiments, the hydrogen peroxide solution in step 4) is prepared by the following method: prepare a solution according to the mass ratio of H2O2:H2O of 1:(15-30), then add 0.5‰-2‰ alkali to the solution, heat to dissolve, and mix evenly.

[0012] The alkali mentioned is either sodium hydroxide or potassium hydroxide.

[0013] In some specific embodiments, the hydrogen peroxide solution also contains copper or iron blocks.

[0014] In some specific embodiments, the soaking process conditions in step 4) are: soaking in hydrogen peroxide solution at 50-60℃ for 5-10 minutes.

[0015] Compared with the prior art, the present invention has at least the following advantages: 1) This invention involves ultrasonically cleaning the silicon electrode to be cleaned in an alkaline degreasing solution to remove surface oil and some particulate matter. Then, the surface and micropores of the silicon electrode are rinsed with pure water, and the rinsed silicon electrode is immersed in pure water for ultrasonic cleaning to remove the attached degreasing solution and particulate matter. Finally, the silicon electrode is immersed in a hydrogen peroxide solution. Under alkaline conditions, the hydrogen peroxide solution can release oxygen, which can enter the fine pores of the silicon electrode with a diameter of 0.2-0.5 mm, quickly and effectively oxidizing the contaminants present inside the pores. This effectively removes particulate matter and contaminants from the surface of the silicon electrode and the inner wall of the pores, allowing for a uniform reaction during subsequent etching, achieving a consistent etching state inside and outside the pores, and preventing trailing color differences.

[0016] 2) The hydrogen peroxide solution in this invention also contains copper or iron metal. The addition of this metal can catalyze the rapid release of a large amount of oxygen from the hydrogen peroxide, resulting in dense, fine bubbles in the solution, which puts the solution into a boiling state. This effectively cleans the inner walls of the micropores and greatly improves the cleaning efficiency. At the same time, this metal does not participate in the reaction in the solution, nor is it corroded or contaminated, and can be used for a long time. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0018] Figure 1 The image shows the physical appearance of the silicon electrode etched after only the cleaning processes in steps 1), 2), and 3) provided in Embodiment 1 of the present invention. Figure 2 This is a physical appearance diagram of the silicon electrode etched after being cleaned by the cleaning method provided in Embodiment 1 of the present invention; Figure 3 This is a physical appearance diagram of the silicon electrode etched after being cleaned by the cleaning method provided in Embodiment 3 of the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are merely descriptive and not limiting, and should not be construed as limiting the scope of protection of the present invention.

[0020] When a quantity, concentration, or other value or parameter is described as a range, preferred range, or preferred upper and lower limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper or preferred values ​​with any lower or preferred values, regardless of whether the range is specifically disclosed. Unless otherwise stated, the numerical range values ​​listed herein include the endpoints of the range and all integers and fractions within that range.

[0021] Unless otherwise stated, all percentages, parts, ratios, etc. in this document are by weight.

[0022] The materials, methods, and embodiments described herein are exemplary and should not be construed as limiting unless otherwise stated.

[0023] In the following examples, the alkaline degreasing solution is model ZB-700, purchased from Zhenbao Technology; The silicon electrode has a diameter of 320 mm, a thickness of 25 mm, and a pore size of ≤0.5 mm; further, the silicon electrode has a diameter of 320 mm, a thickness of 25 mm, and a pore size of 0.4 mm. Example 1

[0024] This embodiment provides an etching pre-cleaning method for micropores in semiconductor silicon electrodes, which includes the following steps: 1) Immerse the silicon electrode to be cleaned in an alkaline degreasing solution at 40°C and sonicate for 10 minutes; 2) Rinse the silicon electrode surface and pores treated in step 1) with pure water for 15 minutes; 3) Immerse the silicon electrode after rinsing in step 2) in pure water and perform ultrasonic cleaning for 10 minutes in an ultrasonic container with a current of 2.0A and a frequency of 50Hz. 4) Mix H2O2 and H2O at a mass ratio of 1:15 to obtain a mixed solution; then add 1‰ sodium hydroxide by mass of the mixed solution, heat to 50℃ to dissolve and mix evenly to obtain a hydrogen peroxide solution; immerse the silicon electrode treated in step 3) in the hydrogen peroxide solution at 50℃ for 10 minutes.

[0025] This application etches the silicon electrode obtained after cleaning in steps 3) and 4) of this embodiment, wherein the etching process is alkaline etching, and the etched silicon electrode is subjected to visual inspection. The surface of the etched silicon electrode after step 3) is as follows: Figure 1 As shown in the figure, the surface of the etched silicon electrode after step 3) has a significant color difference. However, the surface of the etched silicon electrode after step 4) is as shown in the figure. Figure 2 As shown in the figure, the etching reaction of the silicon electrode after step 4) is uniform and consistent, achieving a consistent etching state inside and outside the hole, without any trailing color difference. According to the test results of steps 3) and 4), the particles on the surface and inner wall of the small hole of the silicon electrode after the hydrogen peroxide cleaning step can be effectively cleaned, so that the surface state of the product after subsequent etching is consistent. Example 2

[0026] This embodiment provides an etching pre-cleaning method for micropores in semiconductor silicon electrodes, which includes the following steps: 1) Immerse the silicon electrode to be cleaned in an alkaline degreasing solution at 50°C for 5 minutes; 2) Rinse the small holes of the silicon electrode treated in step 1) with pure water for 15 minutes; 3) Immerse the silicon electrode rinsed in step 2) in pure water and perform ultrasonic cleaning for 8 minutes in an ultrasonic container with a current of 2.4A and a frequency of 40Hz. 4) Mix H2O2 and H2O in a mass ratio of 1:25 to obtain a mixed solution; then add 2‰ potassium hydroxide by mass of the mixed solution, heat to 55℃ to dissolve and mix evenly to obtain a hydrogen peroxide solution; immerse the silicon electrode treated in step 3) in the hydrogen peroxide solution at 55℃ for 6 minutes. Example 3

[0027] This embodiment provides an etching pre-cleaning method for micropores in semiconductor silicon electrodes, which includes the following steps: 1) Immerse the silicon electrode to be cleaned in an alkaline degreasing solution at 50°C for 5 minutes; 2) Rinse the small holes of the silicon electrode treated in step 1) with pure water for 15 minutes; 3) Immerse the silicon electrode rinsed in step 2) in pure water and perform ultrasonic cleaning for 5 minutes in an ultrasonic container with a current of 3.0A and a frequency of 30Hz. 4) Mix H2O2 and H2O in a mass ratio of 1:30 to obtain a mixed solution; add 2‰ of the mass of the mixed solution as alkali, heat to 55℃ to dissolve and mix evenly, then add a catalytic amount of copper block to obtain a hydrogen peroxide solution; immerse the silicon electrode treated in step 3) in the hydrogen peroxide solution at 55℃ for 6 minutes.

[0028] This application etches the silicon electrode prepared in this embodiment, wherein the etching process is alkaline etching (same as in Example 1), and the etched silicon electrode is subjected to appearance inspection, the results of which are as follows. Figure 3 As shown in the figure, the silicon electrode surface prepared in this embodiment has a uniform texture and no color difference defects, and the microstructure of each region on the silicon electrode surface is consistent.

[0029] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for etching and pre-cleaning micropores of semiconductor silicon electrodes, characterized in that, It includes the following steps: 1) Immerse the silicon electrode to be cleaned in an alkaline degreasing solution; 2) Rinse the small holes of the silicon electrode after step 1) with pure water; 3) Immerse the silicon electrode rinsed in step 2) in pure water for ultrasonic cleaning; 4) Immerse the silicon electrode treated in step 3) in hydrogen peroxide solution.

2. The etching pre-cleaning method for semiconductor silicon electrode micropores according to claim 1, characterized in that, The soaking process conditions described in step 1) are soaking in an alkaline degreasing solution at 40-50℃ for 5-10 minutes.

3. The etching pre-cleaning method for semiconductor silicon electrode micropores according to claim 1, characterized in that, The silicon electrode mentioned in step 1) has a diameter of 320 mm, a thickness of 25 mm, and a pore size of ≤0.5 mm.

4. The etching pre-cleaning method for semiconductor silicon electrode micropores according to claim 3, characterized in that, The pore size of the silicon electrode mentioned in step 1) is 0.2-0.5 mm.

5. The etching pre-cleaning method for semiconductor silicon electrode micropores according to claim 1, characterized in that, The ultrasonic cleaning process conditions described in step 3) are: ultrasonic treatment for 5-15 minutes at a current of 2.0-3.0A and a frequency of 30-50Hz.

6. The etching pre-cleaning method for semiconductor silicon electrode micropores according to claim 1, characterized in that, The hydrogen peroxide solution mentioned in step 4) is prepared by the following method: prepare the solution according to the mass ratio of H2O2:H2O of 1:(15-30), then add 0.5‰-2‰ alkali to the solution, heat to dissolve, and mix evenly.

7. The etching pre-cleaning method for semiconductor silicon electrode micropores according to claim 6, characterized in that, The hydrogen peroxide solution also contains copper or iron.

8. The etching pre-cleaning method for semiconductor silicon electrode micropores according to claim 7, characterized in that, The soaking process conditions in step 4) are: soaking in hydrogen peroxide solution at 50-60℃ for 5-10 minutes.

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