Adhesive-less carriers for chemical mechanical polishing

Abstract

Embodiments of the disclosure relate to a system, apparatus and method for polishing thin substrates with high planarity. The apparatus comprises a chemical mechanical polishing head and a plate. The polishing head comprises a bottom surface, a retaining ring, a workpiece-receiving pocket defined between the bottom surface and the retaining ring, and at least one vacuum port adapted to provide a vacuum to the workpiece-receiving pocket through the bottom surface of the polishing head. The plate is disposed in the workpiece-receiving pocket such that the upper side of the plate faces the bottom surface of the polishing head and the lower side of the plate faces away from the bottom surface of the polishing head. The plate has a geometry or a material property configured to allow fluid to pass between the upper side and the lower side of the plate upon application of vacuum in the workpiece-receiving pocket.

Description

BACKGROUNDField[0001]Embodiments of the disclosure generally relate to a system, apparatus and method for polishing thin substrates with high planarity.Description of the Related Art[0002]Semiconductors and microelectronic chips are formed starting with a substrate, usually made of silicon. The chips are made on the surface of the substrate using a variety of different deposition and etch processes. In order to make the chips smaller, there are efforts to reduce the thickness of the substrate on which the active circuitry is formed. However, thinner substrates have a high risk of warping and breaking during the deposition and etching processes. In order to prevent warpage and breaking, the substrate is temporarily bonded to a thicker carrier using an adhesive. After bonding, the substrate is thinned, for example, by mechanical grinding.[0003]The ground substrate is then polished using chemical mechanical polishing (CMP) processes to obtain good total thickness variation (TTV) and lo...

AI Technical Summary

Benefits of technology

The patent provides a system, apparatus, and method for polishing thin substrates with high planarity. The system includes a polishing head and a plate, which can hold a substrate during polishing. The polishing head has a vacuum port to create a vacuum in the substrate pocket, while the plate has a property that allows fluids to pass through it during the vacuum. This helps to ensure consistent and high-quality polishing. The method involves vacuum chucking the substrate onto the polishing head and using the polishing pad for effective polishing. Overall, this patent provides a solution for polishing thin substrates with high accuracy.

Problems solved by technology

However, thinner substrates have a high risk of warping and breaking during the deposition and etching processes.

However, these adhesives are unable to tolerate temperatures greater than 180° C. Therefore, it is not possible to use thin substrates that are temporarily bonded to carriers with adhesives for subsequent substrate-to-substrate bonding at higher temperature (100-400° C.) for substrate-to-substrate stacking.

However, the high lateral forces during polishing can overcome the electrostatic chucking force and cause the substrate to slip out from under the carrier.

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