A Coarse Polishing Process for Reducing the Overall Flatness of Gallium Arsenide Double Polishing Chips

Abstract

The invention discloses a rough polishing process for reducing the overall flatness of the gallium arsenide double-polished sheet, which comprises the following steps: after a rough polishing solutionis prepared, uniformly placing epoxy resin planetary wheels on a polishing disk surface; then, upwards placing the front side of the gallium arsenide double-polished sheet with the thickness deviation of 3 [mu] m in the hole of the epoxy resin planetary wheel; executing a self-checking program; checking the self-spinning conditions of the epoxy resin planetary wheels and the gallium arsenide double-polished sheet; after the self-checking program is executed, descending the upper polishing disc to finish execution of the rough polishing program for the first time; after the first rough polishing program is finished, turning over the gallium arsenide double-polished sheet; placing the back side of the double-polished sheet upwards and executing the self-checking program; then, executing therough polishing program for the second time; after ten times of operation are repeated, taking out the gallium arsenide double-polished sheet from the epoxy resin planetary wheels; and putting into awhite basket for cleaning and spin-drying. According to the embodiment of the invention, the overall flatness of the gallium arsenide double-polished sheet is effectively improved.

Description

technical field [0001] The invention relates to a rough polishing process for reducing the overall flatness of a gallium arsenide double-throwing sheet, belongs to the technical field of semiconductor material preparation, and is suitable for a double-sided rough polishing method used in the preparation process of a gallium arsenide double-throwing sheet. Background technique [0002] With the development of semiconductor integrated circuits, the diameter of gallium arsenide double throw wafers gradually increases. Although small-diameter GaAs double-polishing wafers are still processed by single-side polishing, in order to pursue better polishing quality, double-side polishing has gradually become the main processing technology for large-diameter GaAs double-polishing wafers. However, the reduction of the electronic characteristic line width and the improvement of the integration level put forward higher requirements for the uniformity of removal on-chip of GaAs double-thro...

AI Technical Summary

Problems solved by technology

Different from single-sided chemical mechanical polishing, in the process of double-sided chemical mechanical polishing, the front and back of gallium arsenide double-throwing wafers are removed at the same time. At present, the commonly used polishing time is 890s, and the polishing pressure is 6kg per piece. The polishing cloth model is SUBAⅣ or SUBAⅩ, the speed of the polishing disc is 45rpm, the speed of the inner ring gear is 35rpm, the speed of the outer ring gear is 25rpm, and the speed of the inner and outer ring gears is operated at a ratio of 1.4:1. Finally, a product with a standard thickness was obtained, but due to the fast speed and the fast removal rate on the surface, the running track of the gallium arsenide double throwing disc was mainly concentrated in the center area of ​​the polishing cloth, and the loss in the center area of ​​the polishing cloth was greater than the edge loss during the polishing process of 890s , so in the subsequent processing process, the removal rate of the center of the GaAs double-throw wafer will decrease, while the removal rate of the edge will remain unchanged, which will cause the center of the GaAs double-throw wafer to be thicker than the edge, and thus make the GaAs double-throw wafer The overall flatness is increased, so the current process is difficult to ensure the overall flatness while ensuring the surface quality of the throwing plate. Usually, the overall flatness can only be guaranteed at 3 µm, and the maximum local flatness per 4 square microns is basically 2.5-3 µm. The average value can only guarantee 2µm

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