US 12,622,195 B2 · Methods for polishing bulk silicon devices

Abstract

Methods for polishing bulk silicon are disclosed. In one aspect, mechanical polishing is facilitated by cyclically alternating between a silicon reactive slurry and deionized water while a mechanical polishing head operates on a surface. In exemplary aspects, the polishing head is polishing a bulk silicon carrier wafer to expose a backside of a radio frequency (RF) complementary metal oxide semiconductor (CMOS) switch, although other semiconductors may also benefit from exemplary aspects of the present disclosure. While the silicon slurry is present, a reaction between the bulk silicon and the slurry takes place allowing the polishing head to remove the bulk silicon. The deionized water interrupts this reaction and helps prevent overpolishing which might otherwise damage the device.

Claims16

Dependent claims

A method for exposing a semiconductor device for backside processing, the method comprising:

providing the semiconductor device comprising a trench delimited by insulator sidewalls;
grinding away a portion of a backside of the semiconductor device;
selecting a slurry time based on a desired thickness of silicon to be removed from the backside of the semiconductor device, where the slurry time corresponds to an incubation period between a silicon slurry and silicon on the backside of the semiconductor device;
polishing the backside of the semiconductor device with the silicon slurry and a polishing head such that silicon in the trench is removed at a pace faster than any silicon between the insulator sidewalls and the backside;
and
rinsing the semiconductor device with deionized water to remove the silicon slurry and interrupt the reaction between the silicon slurry and the silicon.

3 more elements

Dependencies are inferred from the claim text.

Methods for polishing bulk silicon devices

Life of this patent

Methods for polishing bulk silicon devices

Life of this patent

Abstract

Claims16