Method for cleaning high-cleanliness monocrystal silicon grinding slice

Abstract

The invention discloses a method for cleaning a high-cleanliness monocrystal silicon grinding slice. The method includes the steps of, firstly, carrying out initial cleaning on the silicon slice, then adopting a low-concentration inorganic base solution to carry out microscale thickness-removal cleaning on the surface of the silicon slice, enabling a surface-layer smashed crystal layer to react with the solution so as to remove 2-5 micrometer surface-layer smashed crystal layer, and peeling surface inlaid objects. Therefore, cleanliness of the surface of the silicon slice is ensured, an external-gettering function of the silicon slice is kept, and the aim of clean cleaning is achieved.

Description

technical field [0001] The invention relates to the field of single crystal silicon chip processing and manufacturing, in particular to a cleaning method for a high cleanliness single crystal silicon grinding chip. Background technique [0002] As we all know, semiconductor monocrystalline silicon wafers are mainly used to make IC integrated circuits and discrete devices. Since IC manufacturing and device manufacturing processes require high cleanliness, the silicon wafers used as substrates also have high cleanliness requirements. The single crystal silicon growth process is grown directly from the melt under vacuum and low pressure. Qualified crystals are cut to form silicon wafers, and the surface of the silicon wafers is cleaned after heat treatment, chamfering and grinding. The quality of the cleaning process has a direct impact on the surface quality of the finished silicon wafer. [0003] In addition, silicon wafers are ground with cast iron discs for two-way grindi...

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Problems solved by technology

[0003] In addition, silicon wafers are ground with cast iron discs for two-way grinding, so that the silicon wafers reach a uniform thickness. During the grinding process, a broken crystal layer is inevitably formed on the surface of the silicon wafers. Some metal iron, abrasives, silicon powder, and even organic matter will be inlaid during grinding. In the broken crystal layer, traditional cleaning generally uses ultrasonic cleaning, which cannot achieve good removal of surface impurities

It is easy to introduce impurities in the process of device manufacturing such as diffusion, resulting in a decrease in device performance

The cleaning method involved in the patent 200910154751.8 "Cleaning Method of Single Crystal / Polycrystalline Silicon Wafer" does not carry out effective surface organic removal, which increases the unevenness of the surface after cleaning, and the concentration of inorganic alkali on the silicon wafer is relatively high, about 30-50% , such a large concentration of lye is easy to volatilize in actual production, which is not good for operators, and the on-site environment is poor. At the same time, it also increases the difficulty of surface cleaning in the later stage, which may easily cause alkali metal residues on the surface and affect the surface quality of silicon wafers.

At the same time, there is ultrasonic treatment in the inorganic alkali reaction, and ultrasonic is easy to form cavitation on the surface of the silicon wafer, so it will cause uneven reaction on the surface of the silicon wafer and there will be chromatic aberration

Patent 200910035260.1 "A Method for Cleaning Silicon Wafers" involves the dehydration of a large amount of anhydrous ethanol. As we all know, anhydrous ethanol is highly volatile and flammable. Items, in actual production, there is a greater potential safety hazard