Apparatus and method for plating solution analysis

Abstract

A method and apparatus for analyzing plating solutions. The apparatus generally includes a plating cell, a reference electrolyte input, one or more external additive pumps, and a process controller. In one embodiment, the plating cell includes a cavity therein having a larger volumetric portion adjacent a smaller volumetric portion adapted to hold one or more solutions therein. The plating cell also includes a base disposed adjacent the bottom of the plating cell and adapted to receive and mix one or more test solutions as part of the plating solution analysis. In one configuration, the base includes electrical ports adapted to connect stimulation signals to a working electrode, counter electrode, and reference electrode disposed within the cell. The base also includes a thermal sensor in thermal contact with test solutions contained within the vessel.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of co-pending U.S. patent application Ser. No. 10 / 287,901, filed Nov. 4, 2002 (APPM / 006884). The aforementioned related patent application is herein incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] Embodiments of the invention generally relate to an apparatus and method for conducting chemical analysis of substrate plating solutions. [0004] 2. Description of the Related Art [0005] Metallization of sub-quarter micron sized features is a foundational technology for present and future generations of integrated circuit manufacturing processes. More particularly, in devices such as ultra large scale integration-type of devices, i.e., devices having integrated circuits with more than a million logic gates, the multilevel interconnects that lie at the heart of these devices are generally formed by filling high aspect ratio interconnect features with a conductive mate...

AI Technical Summary

Problems solved by technology

However, as interconnect sizes decrease and aspect ratios increase, efficient void-free interconnect feature fill by conventional deposition techniques becomes increasingly difficult.

Unfortunately, as test volumes may vary from a few milliliters to several hundred milliliters, the cell size must be changed accordingly to accommodate the differing test volumes.

Further, as tubes or syringes are used to inject the additives into the plating solutions, it is difficult to accurately inject a microliter or less of the additives into the plating solutions as the volume of the additives must be large enough to be dispensed as a droplet.

However, residual additives contained within the tubes may diffuse out into the reference bath during the test and contaminate the measurement.

Accordingly, due to the potential variation of additives due to the imprecise injections, a plating solution under test may be incorrectly analyzed and therefore cause a plating problem that may affect several batches of substrates affecting the plating throughput, and may ultimately increase the cost of production.

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