Seal rings in electrochemical processors

Abstract

A seal ring for an electrochemical processor does not slip or deflect laterally when pressed against a wafer surface. The seal ring may be on a rotor of the processor, with the seal ring having an outer wall joined to a tip arc through an end. The outer wall may be a straight wall. A relatively rigid support ring may be attached to the seal ring, to provide a more precise sealing dimension. Knife edge seal rings that slip or deflect laterally on the wafer surface may also be used. In these designs, the slipping is substantially uniform and consistent, resulting in improved performance.

Description

BACKGROUND OF THE INVENTION[0001]Production of semiconductor integrated circuits and other micro-scale devices typically requires formation of multiple metal layers on a wafer or other substrate. By electroplating metals layers in combination with other steps, such as planarizing, etching and photolithography, patterned metal layers forming the micro-scale devices are created.[0002]Electroplating is performed with the substrate, or one side of the substrate, in a bath of liquid electrolyte, and with electrical contacts touching a conductive layer on the substrate surface. Electrical current is passed through the electrolyte and the conductive layer. Metal ions in the electrolyte deposit or plate out onto the substrate, creating a metal layer on the substrate. The metal ions also tend to plate out onto the electrical contacts as well. This affect, referred to as “plate-up” changes the electric field around the contacts, causing non-uniform plating. The metal plated onto the electrica...

AI Technical Summary

Benefits of technology

The new seal ring in this patent is designed not to slip when sealed against a wafer surface. It is attached to a rotor and has a straight outer wall. It can be molded onto a metal support ring or used with knife edge seal rings that slip consistently. This design improves performance and reduces the area of contact with the wafer, resulting in higher yield.

Problems solved by technology

This affect, referred to as “plate-up” changes the electric field around the contacts, causing non-uniform plating.

The metal plated onto the electrical contacts consequently must be removed, adding to the time requirements and complexity of the manufacturing process.

Although the use of a seal in a dry contact ring solves the plate-up problem, dry contact rings have their own disadvantages.

Initially, the seal of a dry contact ring necessarily contacts or covers an annular shaped area on the substrate surface, which area cannot be used to form devices.

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