CN-122003111-A - Method for improving cleaning efficiency of back hole before gold plating

CN122003111ACN 122003111 ACN122003111 ACN 122003111ACN-122003111-A

Abstract

The invention discloses a method for improving cleaning efficiency before back hole gold plating, which comprises the steps of detecting components of a position to be etched on a wafer by using an EDS, etching the wafer by using an etching machine to form a back hole, continuously detecting signals on the surface of the wafer until gold signals appear as etching end points in the etching process, ending the etching process, detecting the components of the back hole by using the EDS to detect signals of the etched position of the wafer, detecting the surface state of the side wall of the back hole and the roughness of the gold surface of an etching stop layer by using an SEM, wherein the surface state of the side wall is in a smooth state or a rough state, configuring a shower head according to the signal types, the surface state of the side wall and the roughness of the gold surface, and cleaning the back hole by using the configured shower head until the surface state of the side wall is in the smooth state, wherein the signals of the etching position only comprise gold signals and signals derived from semiconductor materials. The invention can simplify the working procedure and improve the cleaning efficiency.

Inventors

YANG YUNCHANG
BIAN XUMING
XU HAO
FU SHENGQUAN
FENG RUI

Assignees

成都航天博目电子科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260209

Claims (9)

1.A method for improving cleaning efficiency of back hole pre-gold plating, comprising: step S1, detecting components of a position to be etched on a wafer by using EDS; Step S2, etching the wafer by using an etching machine to form a back hole, and continuously detecting signals on the surface of the wafer in the etching process until gold signals appear as etching end points, and ending the etching process; Step S3, detecting a signal of the etched position of the wafer by using EDS, and detecting a back hole component, wherein the signal comprises a signal from a mask, a signal from a semiconductor material and a gold signal; S4, checking the surface state of the side wall of the back hole and the roughness of the gold surface of the etching stop layer by using SEM, wherein the surface state of the side wall is in a smooth state or a rough state; Step S5, configuring a shower head according to the signal type in the step S3, wherein the shower head comprises a central single-hole shower head, a super-small Kong Linyu head in a shape of a Chinese character 'mi' and a cross-shaped small Kong Linyu head; And step S6, cleaning back holes by using the shower head configured in the step S5 according to the signal type in the step S3, the side wall surface state and the gold surface roughness in the step S4 until the side wall surface state is in a smooth state, wherein the signal of the etching position is only a gold signal and a signal derived from a semiconductor material.
2. The method as recited in claim 1, further comprising: and S7, performing plating layer deposition on the back holes of the wafer by using metal evaporation equipment, and performing back hole gold electroplating by using electroplating equipment.
3. The method according to claim 1 or 2, wherein in step S3 the signals derived from the mask comprise inorganic signals comprising carbon and oxygen signals and metal signals comprising metallic nickel signals and metallic copper signals, and the signals derived from the semiconductor material comprise Si signals, C signals, ga signals and As signals.
4. The method according to claim 3, wherein in step S5, a shower head with a single center opening is provided when the mask signal is an inorganic signal, and a shower head with a super-small or cross-shaped opening is provided when the mask signal is a metal signal.
5. The method of claim 4, wherein the metal signal is a metal nickel signal and the range of the metal nickel signal is 16-30%, the ultra-small Kong Linyu heads are configured in a zig-zag shape.
6. The method of claim 1 or 2, wherein the ratio of the opening sizes of the mi-shaped ultra-small holes, the cross-shaped small holes and the central single opening is 1:2:4.
7. The method according to claim 3, wherein in step S6, when the signal derived from the mask is an inorganic signal, the acetone cleaning, the piranha solution soaking, the deionized water rinsing and the absolute ethanol rinsing are sequentially performed when the sidewall surface state is a smooth state and the gold surface roughness is 160 to 500 a, the acetone ultrasonic cleaning, the piranha solution soaking and the absolute ethanol soaking cleaning are sequentially performed when the sidewall surface state is a smooth state and the gold surface roughness is 500 to 1 μm, and the DMSO cleaning, the EKC solution soaking and the absolute ethanol soaking cleaning are sequentially performed when the sidewall surface state is a rough state.
8. The method according to claim 3, wherein in step S6, in the case where the signal derived from the mask is a metal signal, the metal signal is a metal copper signal, the metal signal is a metal nickel signal, the metal signal is cleaned with a solution containing one or more of HF, HNO 3 、H 2 SO 4 , and H 3 PO 4 , and the solution containing one or more of a strong acid including one or more of hydrochloric acid, sulfuric acid, nitric acid, concentrated nitric acid, and concentrated hydrochloric acid, and an additive including one or more of a chloride ion, an oxidizing agent, and a surfactant.
9. The method of claim 8, wherein the wafer is automatically moved between SEM equipment, an etcher, and a wafer cleaning equipment, including SEM metrology equipment and EDS equipment, by a robotic arm, the wafer cleaning equipment configured to perform back hole cleaning by a showerhead based on the cleaning signals.

Description

Method for improving cleaning efficiency of back hole before gold plating Technical Field The invention belongs to the field of semiconductor device manufacturing, and particularly relates to a method for improving cleaning efficiency before back hole gold plating. Background The microwave semiconductor device made of the compound semiconductor is required to realize higher working frequency, and has larger gain and bandwidth at high frequency, and heat dissipation is one of the main problems which are urgent to be solved. If the generated heat cannot be solved in time, the resistivity of the metal wire will continuously increase with the rise of temperature in a short period, so that the signal delay on the metal wire will be greatly improved, and the expected speed performance is difficult to obtain, and if the device works for a long time, the device may be blown, and thus the whole circuit may be disabled. The semiconductor material is etched into the back hole, and the back hole is metallized, so that heat dissipation can be guaranteed, the semiconductor material can serve as a lead, and the reliability of the device is greatly improved. One common way of back hole metallization is electroplating. Typically, prior to electroplating, the interior of the back hole needs to be cleaned to remove impurities created by etching, including plasma ions, photoresist, etched region material, and etch stop layer (gold). If the impurities are not cleaned, the back hole metallization is incomplete or even absent, so that the device cannot dissipate heat in time under high current, and the risk of burning exists. As shown in fig. 1, the conventional method for cleaning the back hole before electroplating gold is to clean the gold residues through KI after the wafer surface cleaning, mask manufacturing process and back hole etching process, clean the residues with solvent, and deposit and plate back hole gold after cleaning. The existing cleaning process has the defects that the working procedure is complicated, the treatment result is unexpected, the gold is leached through KI, the residues are treated, then the solvent is used for removing the organic residues on the bottom layer, and if the stubborn residues are encountered, the two steps are needed to be alternately repeated for a plurality of times, so that the efficiency is low. Disclosure of Invention The invention aims to provide a method for improving the cleaning efficiency before back hole gold plating, which can simplify the working procedures and improve the cleaning efficiency. In order to achieve the above object, an aspect of the present invention provides a method for improving cleaning efficiency before back hole plating, comprising: step S1, detecting components of a position to be etched on a wafer by using EDS; Step S2, etching the wafer by using an etching machine to form a back hole, and continuously detecting signals on the surface of the wafer in the etching process until gold signals appear as etching end points, and ending the etching process; Step S3, detecting a signal of the etched position of the wafer by using EDS, and detecting a back hole component, wherein the signal comprises a signal from a mask, a signal from a semiconductor material and a gold signal; S4, checking the surface state of the side wall of the back hole and the roughness of the gold surface of the etching stop layer by using SEM, wherein the surface state of the side wall is in a smooth state or a rough state; Step S5, configuring a shower head according to the signal type in the step S3, wherein the shower head comprises a central single-hole shower head, a super-small Kong Linyu head in a shape of a Chinese character 'mi' and a cross-shaped small Kong Linyu head; And step S6, cleaning back holes by using the shower head configured in the step S5 according to the signal type in the step S3, the side wall surface state and the gold surface roughness in the step S4 until the side wall surface state is in a smooth state, wherein the signal of the etching position is only a gold signal and a signal derived from a semiconductor material. According to the method for improving the cleaning efficiency before back hole gold plating, the working procedure can be simplified, and the cleaning efficiency can be improved. Drawings For a clearer description of the technical solutions of the present invention, the following description will be given with reference to the attached drawings used in the description of the embodiments of the present invention, it being obvious that the attached drawings in the following description are only some embodiments of the present invention, and that other attached drawings can be obtained by those skilled in the art without the need of inventive effort: FIG. 1 is a flow chart of a prior art method of cleaning a back hole before electro-gold plating; FIG. 2 is a flow chart of a method for improving cleaning efficiency before back hole plating in