A method and device for wireless photoelectrochemical mechanical polishing of semiconductor wafers

Abstract

Semiconductor wafer wireless photoelectrochemical mechanical polishing method: fix the wafer on the polishing head; paste the polishing pad on the bottom of the polishing plate with the same diameter; set a pair of positive and negative electrodes on the bottom wall of the through hole, and merge them into the two bus lines on the top of the plate , connected to the positive and negative terminals of the power supply through a conductive slip ring; during processing, ultraviolet light is irradiated to the wafer through the through hole; the polishing liquid is dripped into the through hole to form a wafer surface, polishing liquid layer and positive and negative electrodes at the bottom. In the photolytic cell, the electrode and the wafer are separated by a polishing pad; after applying voltage, the wafer surface at the bottom of the photolytic cell is in the electric field between the two electrodes, and is oxidized into a soft surface oxide film according to the principle of bipolar electrochemical; Co-rotation of the disc / pad with the wafer allows all surfaces of the wafer to alternate evenly between the photoelectrochemical oxidation and mechanical rubbing steps. The device designed by the invention can efficiently and high-quality process various semiconductor wafers such as gallium nitride wafers with non-conductive sapphire as substrates under normal temperature and pressure, and has great economic significance and popularization value.

Description

technical field

[0001] The invention belongs to the technical field of semiconductor manufacturing, in particular to a method and device for wireless photoelectrochemical mechanical polishing of semiconductor wafers. Background technique

[0002] The third-generation compound semiconductor gallium nitride and silicon carbide have the characteristics of good thermal conductivity, high breakdown electric field and fast electron saturation rate, and are suitable for making high-temperature, high-frequency and radiation-resistant high-power devices. Manufacturing devices from wafers requires frequent polishing processes. At present, the main technology is chemical mechanical polishing (CMP). The processing mechanism is to use the mechanical friction of polishing pads and abrasives while chemically oxidizing the wafer to form a soft surface oxide layer. Remove the oxide layer. However, gallium nitride and silicon carbide differ from other semiconductors in that their chemistry i...

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