CN115831712A

CN115831712A - Deep hole cleaning method after semiconductor wafer etching

Info

Publication number: CN115831712A
Application number: CN202211515163.4A
Authority: CN
Inventors: 王超
Original assignee: Chengdu Hiwafer Technology Co Ltd
Current assignee: Chengdu Hiwafer Technology Co Ltd
Priority date: 2022-11-29
Filing date: 2022-11-29
Publication date: 2023-03-21

Abstract

The invention discloses a method for cleaning a deep hole of a semiconductor wafer after etching, which comprises the following steps: cleaning the etched semiconductor wafer for the first time by adopting an EKC solution, wherein the EKC solution is a mixed solution of an NMP solvent and amine with alkalinity; carrying out secondary cleaning on the semiconductor wafer by adopting an NMP solvent; cleaning the semiconductor wafer for the third time by using an IPA solvent; and cleaning the semiconductor wafer for the fourth time by adopting pure water: cleaning the semiconductor wafer for the fifth time by using a KI solvent; carrying out sixth cleaning on the semiconductor wafer by adopting pure water; carrying out seventh cleaning on the semiconductor wafer by adopting a DHF solvent; carrying out eighth cleaning on the semiconductor wafer by adopting pure water; and drying the semiconductor wafer. By adding KI and DHF solvent for cleaning, the invention can completely clean the polymer in the deep hole and the metal residue generated in dry etching, and ensure the performance, yield and reliability of the finished product of the semiconductor device.

Description

Deep hole cleaning method after semiconductor wafer etching

Technical Field

The invention relates to the technical field of semiconductor manufacturing processes, in particular to a method for cleaning a deep hole after semiconductor wafer etching.

Background

In the production process of semiconductor devices, the etched deep holes need to be cleaned, and the deep hole cleaning is directly related to the realization of the final functions of the semiconductor devices. If the polymer can not be cleaned, the polymer can directly influence the conductivity of a metal layer formed in a subsequent gold plating process, so that the grounding performance of a device is influenced, the performance, the yield and the reliability of a finished product can be seriously influenced, even the electrical function can not be realized, and the product is scrapped.

The deep hole is usually formed by a dry etching process, polymer is generated in the dry etching process, in the current process, the polymer generated in the dry etching process is removed by a wet process for cleaning, and the chemical used for cleaning is EKC, which is an organic solvent, can play a significant role in the process of cleaning the polymer and is not corrosive. However, with the increase of patterns and the increase of depth on the device, the etching depth can reach 100 microns, and in addition to polymers, other metal-containing byproducts are generated in the dry etching process. When the cleaning of the polymer and metal byproducts in the side walls and deep trenches in a complex pattern is faced, the pure EKC cleaning capability is slightly insufficient, which may result in polymer and metal substance residues at the bottom and side walls of the deep trenches, and further in the process of growing metal at the bottom and side walls of the deep trenches, the conduction function of the formed metal layer is affected, even the metal layer falls off, and the direct consequence is that the electrical property, yield and reliability of the device are seriously reduced, and even the electrical property function cannot be realized at all. The economic loss brought indirectly to the company and the loss brought by factors such as the delay of the product delivery period of the client are immeasurable.

Disclosure of Invention

The invention aims to overcome the problem that the existing deep hole cleaning technology is difficult to completely clean polymers in deep holes, other byproducts formed in dry etching and metal-containing byproducts, and provides a deep hole cleaning method after semiconductor wafer etching.

The purpose of the invention is realized by the following technical scheme:

mainly provides a method for cleaning a deep hole after etching a semiconductor wafer, which comprises the following steps:

s1, cleaning an etched semiconductor wafer for the first time by adopting an EKC solution, wherein the EKC solution is a mixed solution of an NMP solvent and amine with alkalinity;

s2, carrying out secondary cleaning on the semiconductor wafer by adopting an NMP solvent;

s3, cleaning the semiconductor wafer for the third time by using an IPA solvent;

s4, cleaning the semiconductor wafer for the fourth time by adopting pure water;

s5, cleaning the semiconductor wafer for the fifth time by adopting a KI solvent;

s6, carrying out sixth cleaning on the semiconductor wafer by adopting pure water;

s7, carrying out seventh cleaning on the semiconductor wafer by adopting a DHF solvent;

s8, carrying out eighth cleaning on the semiconductor wafer by adopting pure water;

and S9, drying the semiconductor wafer.

In one example, the first cleaning, the second cleaning, the third cleaning, the fourth cleaning, the fifth cleaning and the sixth cleaning are performed by soaking or spraying.

In one example, the process time of the first cleaning is 30 minutes, and the process temperature is 90 degrees.

In one example, the second cleaning process is carried out for 30 minutes at a process temperature of 90 degrees.

In one example, the third cleaning process is carried out for 1-5 minutes.

In one example, the process time of the fifth cleaning is 1 minute to 5 minutes, and the process temperature is normal temperature.

In one example, the process time of the seventh cleaning is 1 minute to 5 minutes, and the process temperature is normal temperature.

In one example, the process time of the fourth, sixth and eighth cleaning is 1-5 minutes.

In one example, the deep hole cleaning method after the semiconductor wafer etching is carried out, the drying mode is spin drying or nitrogen blow drying, and the drying duration is 5 minutes.

In one example, the concentration of the NMP solvent is more than 95%, and the concentration of the IPA solvent is more than 95%.

It should be further noted that the technical features corresponding to the above options can be combined with each other or replaced to form a new technical solution.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, after EKC and NMP solvent cleaning is carried out, KI and DHF solvent cleaning is added, so that polymers in deep holes and metal residues generated in dry etching can be completely cleaned, and the performance, yield and reliability of finished products of semiconductor devices are ensured.

Drawings

Fig. 1 is a flowchart illustrating a deep hole cleaning method after etching a semiconductor wafer according to an embodiment of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not intended to indicate or imply relative importance.

Furthermore, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, a method for cleaning a deep hole after etching a semiconductor wafer is provided, which comprises the following steps:

s1, cleaning an etched semiconductor wafer for the first time by adopting an EKC solution, wherein the EKC solution is a mixed solution of an NMP solvent and amine with alkalinity; the EKC solution contains NMP (N-Methyl pyrrolidone) solvent and is alkaline, so that the EKC solution has a certain etching effect on the bulk of a semiconductor wafer, but can play a significant role in cleaning a polymer and simultaneously avoid or reduce the etching effect as much as possible by adjusting the addition ratio of amine. In this embodiment, the first cleaning mode is soaking or spraying, and when the cleaning mode is soaking, the soaking time is 30 minutes, and the soaking temperature is 90 °.

S2, the semiconductor wafer is cleaned for the second time by adopting an NMP solvent, wherein the NMP solvent is a pure organic solvent and is not corrosive, so that the method can play a remarkable role in the process of cleaning the polymer and cannot generate a moment effect on the semiconductor wafer body. Optionally, the concentration of NMP solvent is 95% or more.

In this embodiment, the second cleaning mode is soaking or spraying, and when the cleaning mode is soaking, the soaking time is 30 minutes, and the soaking temperature is 90 °.

And S3, carrying out third cleaning on the semiconductor wafer by using an IPA (isopropyl alcohol) solvent, wherein the concentration of the IPA solvent is more than 95%. In this embodiment, the process time of the third cleaning method R is 1 minute to 5 minutes.

And S4, carrying out fourth cleaning on the semiconductor wafer by adopting pure water, wherein in the embodiment, the fourth cleaning mode is soaking or spraying, and the cleaning process time is 1-5 minutes. Optionally, the pure water is deionized water.

And S5, carrying out fifth cleaning on the semiconductor wafer by using a KI solvent, wherein in the embodiment, the fifth cleaning is carried out by soaking or spraying, and the cleaning process time is 1-5 minutes. Wherein, KI solvent refers to potassium iodide solvent.

And S6, carrying out sixth cleaning on the semiconductor wafer by adopting pure water, wherein in the embodiment, the sixth cleaning mode is soaking or spraying, and the cleaning process time is 1-5 minutes. Optionally, the pure water is deionized water.

And S7, carrying out seventh cleaning on the semiconductor wafer by adopting a DHF solvent, wherein in the embodiment, the seventh cleaning mode is soaking or spraying, and the cleaning process time is 1-5 minutes. Wherein, DHF solvent refers to dilute hydrofluoric acid solvent.

Furthermore, KI and DHF solvents are used for removing metal byproducts except polymers, and in order to ensure the integrity of the deep hole, certain bombardment is required to be carried out on the metal layer at the bottom of the hole in the final stage of deep hole etching, so that metal particles are formed in the hole and mixed with the polymers in the hole, and the metal particles can be dissolved by using KI and DHF.

Further, the residual metal particles are exposed after the fourth cleaning, and then the corresponding metal particles can be removed by using the fifth cleaning (KI solvent) and the sixth cleaning (DHF solvent). If the fifth cleaning (KI solvent) and the sixth cleaning (DHF solvent) are used before the fourth cleaning, the metal particles are protected by the polymer, which is not beneficial to cleaning. There is no definite sequence requirement between step S5 and step S7, and the adjustment can be made according to the actual situation.

And S8, carrying out eighth cleaning on the semiconductor wafer by adopting pure water, wherein in the embodiment, the eighth cleaning mode is soaking or spraying, and the cleaning process time is 1-5 minutes. Optionally, the pure water is deionized water.

And S9, drying the semiconductor wafer in a spin drying mode or a nitrogen drying mode, wherein the drying duration is 5 minutes.

Further, the spraying method preferably adopted by the involved spraying method can bring better cleaning effect.

Further, the setting of the cleaning parameters such as time, temperature, concentration, etc. can be adjusted according to the actual situation.

Through the manner, the deep hole cleaning method after semiconductor wafer etching in the embodiment of the invention can completely clean the polymer in the deep hole and the metal residue generated in dry etching by adding KI and DHF solvent cleaning after EKC and NMP solvent cleaning, thereby ensuring the finished product performance, yield and reliability of the semiconductor device.

The above detailed description is for the purpose of describing the invention in detail, and it should not be construed that the detailed description is limited to the description, and it will be apparent to those skilled in the art that various modifications and substitutions can be made without departing from the spirit of the invention.

Claims

1. A method for cleaning a deep hole of a semiconductor wafer after etching is characterized by comprising the following steps:

and S9, drying the semiconductor wafer.

2. The method as claimed in claim 1, wherein the first cleaning, the second cleaning, the third cleaning, the fourth cleaning, the fifth cleaning and the sixth cleaning are performed by soaking or spraying.

3. The method as claimed in claim 1, wherein the process time of the first cleaning is 30 minutes, and the process temperature is 90 °.

4. The method as claimed in claim 1, wherein the second cleaning is performed for 30 minutes at a temperature of 90 °.

5. The method as claimed in claim 1, wherein the third cleaning process is performed for 1-5 minutes.

6. The method as claimed in claim 1, wherein the fifth cleaning is performed for a time period of 1-5 minutes at a normal temperature.

7. The method as claimed in claim 1, wherein the process time of the seventh cleaning is 1 to 5 minutes, and the process temperature is normal temperature.

8. The method as claimed in claim 1, wherein the process time of the fourth, sixth and eighth cleaning is 1-5 minutes.

9. The method as claimed in claim 1, wherein the drying is spin drying or nitrogen blow drying, and the drying duration is 5 minutes.

10. The method as claimed in claim 1, wherein the concentration of the NMP solvent is 95% or more and the concentration of the IPA solvent is 95% or more.