CN-118824893-B - Substrate etching method and device

Abstract

The invention discloses a substrate etching method and device. The substrate etching method comprises immersing a substrate in a treatment tank containing an etching solution, wet etching the substrate with the etching solution to form a deep structure on the surface of the substrate, and supplying gas into the etching solution based on pulse signals to generate bubbles in the etching solution, wherein one pulse time of the pulse signals comprises a gas supply period and an intermittent period, and the intermittent period depends on diffusion time required by key components in the deep structure to reach diffusion balance after the gas supply period is ended.

Inventors

• WANG HUI
• XU RONG
• WANG JUN
• LI YAZHOU
• ZHANG XIAOYAN

Assignees

• 盛美半导体设备(上海)股份有限公司
• 盛帷半导体设备(上海)有限公司

Dates

Publication Date

20260512

Application Date

20230419

Claims (19)

1. 1. A method of etching a substrate, comprising: Immersing a substrate in a treatment tank containing etching solution, and carrying out wet etching on the substrate through the etching solution, wherein a deep structure is formed on the surface of the substrate; Providing a gas into the etching solution based on a pulse signal for generating bubbles in the etching solution, wherein one pulse time of the pulse signal comprises a gas supply period and an intermittent period, the intermittent period is dependent on a diffusion time required for a critical component in the deep structure to reach diffusion balance after the gas supply period is ended, wherein the critical component comprises etching reactants and/or etching products, the intermittent period is denoted as t2, the diffusion time required for the critical component in the deep structure to reach diffusion balance after the gas supply period is ended is denoted as Td2, t2 is proportional to Td2, and the time required for the critical component in the deep structure to reach diffusion balance after the gas supply period is denoted as t2=k Td2, where k >0, The substrate etching method is used for improving etching uniformity in the deep structure.
2. 2. The method of claim 1, wherein the intermittent period is 10ms to 1s.
3. 3. The method of claim 1, wherein k is not less than 0.5.
4. 4. The method of etching a substrate according to claim 3, wherein the k has a value in a range of 0.5 to 2.
5. 5. The method of claim 1, wherein the gas supply period supplies gas to the etching solution at a first gas amount, and wherein the intermittent period supplies gas to the etching solution at a second gas amount, the second gas amount being less than the first gas amount.
6. 6. The method of claim 5, wherein the second amount of gas is zero.
7. 7. The method according to claim 5, wherein a gas nozzle is disposed in the processing tank for supplying a gas to the etching solution to generate bubbles, and the second gas amount is not less than a critical gas flow, which is a minimum gas flow for avoiding backflow to the gas nozzle.
8. 8. The method of claim 1, wherein the air supply period is 10ms to 1s.
9. 9. The method according to claim 1, wherein the number of bubbles generated in the gas supply period is N, N is a natural number and N is 10 or less.
10. 10. The method of claim 9, wherein the air supply period generates an adjacent bubble spacing time T g that is less than a diffusion time T d1 required for a critical component in a deep structure to reach diffusion equilibrium after a disturbance of a previous bubble in the adjacent bubble.
11. 11. The method of claim 10, wherein the T is g =k 1 T d1 ,k 1 ∈(0,0.5)。
12. 12. The substrate etching method of claim 9, wherein the gas supply period continuously supplies gas to the etching solution.
13. 13. The method of claim 12, wherein the flow rate of the gas continuously supplied to the etching solution is 0.5L/min to 2L/min.
14. 14. The method of etching a substrate according to claim 9, wherein the gas supply period intermittently supplies gas to the etching solution based on N sub-pulse signals each of which generates one bubble, N being a natural number and N being 10 or less.
15. 15. The method of claim 14, wherein the pulse time of each sub-pulse signal is 10ms to 100ms.
16. 16. The method according to claim 14, wherein a flow rate of the gas supplied to the etching solution by the sub-pulse signal is not lower than 2L/min.
17. 17. The method of claim 16, wherein the sub-pulse signal supplies a gas flow rate of 2L/min to 30L/min to the etching solution.
18. 18. The method of claim 1, wherein the pulse signal is periodic or aperiodic.
19. 19. A substrate etching apparatus comprising: A processing tank for containing an etching solution; A holding mechanism for holding a substrate and immersing the substrate in an etching solution, the surface of the substrate being formed with a deep structure; A gas supply part for supplying gas into the etching solution to generate bubbles to disturb the etching solution, and A controller configured to control the gas supply portion to supply gas into the etching solution based on a pulse signal, wherein one pulse time of the pulse signal includes a gas supply period and an intermittent period, the intermittent period is dependent on a diffusion time required for a critical component in the deep structure to reach diffusion balance after the gas supply period is ended, wherein the critical component includes an etching reactant and/or an etching product, the intermittent period is denoted as t2, a diffusion time required for the critical component in the deep structure to reach diffusion balance after the gas supply period is ended is denoted as Td2, t2 is proportional to Td2, and t2=k is denoted as Td2, where k >0, The substrate etching device is used for improving etching uniformity in the deep structure.

Description

Substrate etching method and device Technical Field The present invention relates to the field of semiconductor manufacturing, and in particular, to a method and apparatus for etching a substrate. Background Wet etching is to dip the substrate into an etching solution, and chemically etch the thin film to be removed by the etching solution. In wet etching, gas is also generally supplied to the etching solution to generate bubbles for improving etching effect. Currently, efforts are made in the industry to optimize the flow of the supplied gas and the gas distribution, achieve better etch rates and etch uniformity, and generally focus on improving in-substrate and inter-substrate etch uniformity in terms of improvement of etch uniformity. However, when wet etching is performed on a thin film in a deep structure on a substrate, for example, when wet etching is performed on a silicon nitride film in a deep structure such as a narrow void, a narrow trench, and/or a high aspect ratio via formed on a substrate, etch uniformity in the deep structure will also become an important factor affecting the reliability of a semiconductor device. Macroscopic flow and mass transfer efficiency at the bottom of the deep structure is reduced compared to the top of the deep structure, resulting in different concentrations of etch products and etch reactants at the top and bottom of the deep structure, creating a concentration gradient. And the larger the depth-to-width ratio of the deep structure is, the larger the concentration gradient in the deep structure is, which can increase etching differences at different positions of the deep structure, thereby affecting the etching uniformity in the deep structure. Therefore, improvements in wet etching are needed to regulate etch uniformity in deep structures. Disclosure of Invention In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a method and apparatus for etching a substrate, which are used for solving the problem of non-uniform etching in a deep structure of a substrate in the prior art. To achieve the above and other related objects, the present invention provides a substrate etching method, comprising: Immersing a substrate in a treatment tank containing etching solution, and carrying out wet etching on the substrate through the etching solution, wherein a deep structure is formed on the surface of the substrate; A gas is supplied to the etching solution based on a pulse signal for generating bubbles in the etching solution, and one pulse time of the pulse signal includes a gas supply period and an intermittent period depending on a diffusion time required for a critical component in the deep structure to reach diffusion balance after the gas supply period ends. Optionally, the interval time T g between adjacent bubbles generated in the air supply period is smaller than the diffusion time T d1 required for the critical components in the deep structure to reach diffusion balance after the previous bubble in the adjacent bubbles is disturbed. Optionally, the gas supply period continuously supplies gas to the etching solution. Optionally, the gas supply period intermittently supplies gas to the etching solution based on N sub-pulse signals, each of which generates one bubble, where N is a natural number and N is less than or equal to 10. In another aspect, the present invention further provides a substrate etching apparatus, including: A processing tank for containing an etching solution; A holding mechanism for holding a substrate and immersing the substrate in an etching solution, the surface of the substrate being formed with a deep structure; A gas supply part for supplying gas into the etching solution to generate bubbles to disturb the etching solution, and And a controller configured to control the gas supply part to supply the gas into the etching solution based on a pulse signal, one pulse time of the pulse signal including a gas supply period and an intermittent period, the intermittent period being dependent on a diffusion time required for the critical component in the deep structure to reach diffusion balance after the gas supply period ends. As described above, the invention provides a substrate etching method and device, which have the following beneficial effects: 1) In the wet etching process, gas is provided to the etching solution in a pulse mode, one pulse time comprises a gas supply period and an intermittent period, the intermittent period is determined according to the diffusion time required by the key components in the deep structure to reach diffusion balance after the gas supply period is finished, the disturbance interval of the adjacent gas supply period to the groove is reasonably controlled, the diffusion degree in the groove is regulated and controlled, and the etching uniformity in the groove is further improved; 2) The adjacent bubbles generated in the air supply period have smaller inter