阅读说明：本技术 去除晶圆表面静电荷的方法 (Method for removing electrostatic charge on surface of wafer ) 是由 朱也方 于 2020-03-19 设计创作，主要内容包括：本发明公开了一种去除晶圆表面静电荷的方法,包括如下步骤：步骤S1,对以设定速度旋转的晶圆表面进行预处理,通过晶圆的旋转引流释放静电；步骤S2,对晶圆表面进行清洗。本发明可以避免晶圆清洗时清洗液瞬间接触晶圆表面且晶圆高速旋转而导致晶圆表面产生静电击穿效应,从而可以彻底去除晶圆表面的静电荷。(The invention discloses a method for removing electrostatic charges on the surface of a wafer, which comprises the following steps: step S1, preprocessing the surface of the wafer rotating at a set speed, and discharging static electricity through the rotation drainage of the wafer; step S2, the surface of the wafer is cleaned. The invention can prevent the cleaning liquid from instantly contacting the surface of the wafer and the wafer from rotating at high speed to cause electrostatic breakdown effect on the surface of the wafer when the wafer is cleaned, thereby thoroughly removing the electrostatic charge on the surface of the wafer.)

1. A method for removing electrostatic charge on the surface of a wafer is characterized by comprising the following steps:

step S1, preprocessing the surface of the wafer rotating at a set speed, and discharging static electricity through the rotation drainage of the wafer;

step S2, the surface of the wafer is cleaned.

2. A method for removing electrostatic charge from a wafer surface as claimed in claim 1, wherein in step S1, the set speed of the wafer rotation is less than 80 rpm.

3. A method for removing electrostatic charge from the surface of a wafer as claimed in claim 1, wherein atomized water is sprayed onto the surface of the wafer in step S1.

4. A method as claimed in claim 1, wherein in step S1, atomized isopropyl alcohol is sprayed on the wafer surface.

5. A method as claimed in claim 1, wherein in step S2, the wafer is cleaned with water having a resistance of less than 0.04 mega ohm cm.

6. A method as claimed in claim 1, wherein in step S2, the wafer is cleaned with a diluent.

7. A method for removing electrostatic charge from the surface of a wafer as claimed in claim 1, wherein the method is performed after the wafer is subjected to plasma dry etching and before the wafer is subjected to wet cleaning.

Technical Field

The invention relates to the technical field of semiconductor manufacturing, in particular to a method for removing electrostatic charges on the surface of a wafer in a wet cleaning process of a semiconductor manufacturing process.

Background

In the wafer manufacturing process technology, in order to obtain the pattern required by the integrated circuit, the pattern on the photoresist must be transferred to the wafer, and one of the methods for completing the pattern conversion is to remove the part which is not masked by the photoresist by selective etching. The etching method comprises dry etching and wet etching. The dry etching is a common etching mode, and has the characteristics of good anisotropy and suitability for small-size etching.

In the dry etching process, high etching rate is usually formed by using etching process conditions such as high power, high plasma density and the like, so that high wafer yield is obtained. Specifically, a plasma is generated in a chamber in which the wafer is located, wherein the plasma is generated by ionization of certain gas, and active radicals in the plasma generate physical or chemical selective etching on the surface of the wafer.

In the existing dry etching process, a wafer is usually adsorbed by an electrostatic chuck in a chamber of etching equipment, and after etching is completed, appropriate reverse voltage is applied to the electrostatic chuck, so that the charge distribution on the electrostatic chuck is reversed, and the charge on the wafer can be neutralized. However, since the amount of charge on the wafer is difficult to control, and the magnitude of the reverse voltage applied by the electrostatic chuck power supply is also difficult to control, more electrostatic charge is usually still left on the etching chamber and the surface of the wafer after the dry etching process is completed. In addition, if a film layer having an insulating property is etched, it may cause difficulty in discharging or insufficient discharge of residual static charge.

Moreover, as the semiconductor industry continues to develop, the critical dimensions and line widths including gate oxide, high-k dielectric gate, finfet, etc. continue to shrink, and the electrostatic charge accumulation effect is easily generated on the wafer surface. After the wafer cleaning is changed from trough cleaning to single-wafer cleaning, because chemicals or cleaning liquid instantly contact the surface of the wafer and rotate at a high speed, the surface of the wafer can generate a strong electrostatic breakdown effect, so that a permanent damage is caused, the yield of the wafer is influenced, and even the product is scrapped. Moreover, the larger the effective surface area of the wafer surface, the more severe the static charge build-up and the greater the losses that result. Therefore, how to remove the electrostatic charge on the wafer surface becomes an urgent problem to be solved.

Disclosure of Invention

The invention aims to provide a method for removing electrostatic charges on the surface of a wafer, which can solve the problem that the electrostatic charges on the surface of the wafer cannot be effectively removed in the existing etching process, so that the wafer is defective or even scrapped.

In order to solve the above problems, the method for removing electrostatic charge on the surface of a wafer provided by the invention comprises the following steps:

step S1, preprocessing the surface of the wafer rotating at a set speed, and discharging static electricity through the rotation drainage of the wafer;

step S2, the surface of the wafer is cleaned.

Further, in step S1, the set speed of the wafer rotation is less than 80 rpm.

Further, in step S1, atomized water is sprayed on the surface of the wafer for pretreatment.

Further, in step S1, atomized isopropyl alcohol is sprayed on the surface of the wafer for pretreatment.

Further, in step S2, the cleaning is performed with ultra-low water blocking.

Further, in step S2, washing is performed with a diluent.

The method is used after the wafer is subjected to plasma dry etching and before the wafer is subjected to wet cleaning.

Compared with the prior art, the method sprays atomized water or atomized Isopropanol (IPA) on the surface of the rotating wafer for pretreatment, takes away the static charge on the surface of the wafer through the rotation of the wafer, controls the rotation speed of the wafer to prevent electrostatic breakdown, and then slowly cleans the surface of the wafer by using water or diluent with ultralow resistance, thereby thoroughly removing the static charge on the surface of the wafer.

Drawings

FIG. 1 is a flowchart illustrating steps of a first embodiment of the present invention;

FIG. 2 is a flowchart illustrating steps of a second embodiment of the present invention;

FIG. 3 is a flowchart illustrating the steps of a third embodiment of the present invention;

FIG. 4 is a flowchart illustrating a fourth step of the present invention;

FIG. 5 is a flowchart illustrating a fifth step of the present invention.

Detailed Description

Other advantages and effects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein it is shown in the accompanying drawings, wherein the specific embodiments are by way of illustration. In the following description, specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced or applied in different embodiments, and the details may be based on different viewpoints and applications, and may be widely spread and replaced by those skilled in the art without departing from the spirit of the present invention.