A method for controlling the thickness of heavily mixed products after polishing

Abstract

The invention provides a method for controlling the thickness of heavily mixed products after polishing, comprising the following steps: calculating the removal rate of the wafer during polishing; determining the polishing stage of the wafer according to the initial thickness of the wafer, and calculating the standard removal rate; calculating according to the standard removal rate The polishing time of the incoming material that enters the polishing stage, and is polished according to the polishing time. The beneficial effect of the present invention is that it is used to control the thickness of heavily mixed products during the polishing process, to ensure the uniformity of the thickness of the polished silicon wafer, to ensure the consistency of the thickness in the mass production process, and to facilitate the control of the stability of the geometric parameters of the wafer. .

Description

technical field [0001] The invention belongs to the technical field of semiconductor preparation, in particular to a method for controlling the thickness of heavily doped products after polishing. Background technique [0002] For lightly doped products, the laser can be used to irradiate the surface of the wafer during processing, and reflections will occur on the upper and lower surfaces of the wafer. The reflection spectrum can be obtained through the reflection on the upper and lower surfaces of the wafer, and different The spectral information is converted into wafer thickness information, so that the wafer thickness can be obtained during processing. However, for heavy doped products, the reflection spectrum cannot be obtained after the laser is irradiated on the surface of the wafer, and the thickness information of the wafer cannot be obtained, and the thickness of the wafer cannot be accurately controlled. The thickness after polishing can only be estimated by contr...

AI Technical Summary

Problems solved by technology

However, for heavy doped products, the reflection spectrum cannot be obtained after the laser is irradiated on the surface of the wafer, and the thickness information of the wafer cannot be obtained, and the thickness of the wafer cannot be accurately controlled. The thickness after polishing can only be estimated by controlling the polishing time. This will lead to non-uniform thickness of wafers during batch processing of wafers, and large fluctuations in geometric parameters