Reactors, systems, and methods for electroplating microfeature workpieces

Abstract

Reactors, systems and methods for electroplating and / or electro-etching microfeature workpieces. Reactors in accordance with the invention have a first chamber configured to direct a first processing solution to a processing zone, a second chamber configured to contain a second processing solution different than the first processing solution, and an ion exchange membrane between the first chamber and the second chamber. The reactors also include (a) a support member in the first chamber that contacts the ion exchange membrane across the surface of the membrane, and (b) a counter electrode in the second chamber. The ion exchange membrane enables a low conductivity catholyte to be used in the first chamber and an inert counter electrode in the second chamber. More specifically, the ion exchange membrane prevents nascent oxygen that evolves from the inert counter electrode from reaching the catholyte to reduce oxidation of constituents of the catholyte, consumption of organic additives in the anolyte, and / or accumulation of bubbles and particulates at the workpiece.

Description

TECHNICAL FIELD [0001] This application relates to reactors, systems, and methods for electroplating microfeature workpieces having a plurality of microdevices integrated in and / or on the workpieces. Particular aspects of the present invention are directed toward electroplating workpieces using a low-profile reactor. BACKGROUND [0002] Microfeature devices, such as semiconductor devices, imagers, displays, and micromechanical components, are generally fabricated on and / or in microfeature workpieces using a number of machines that deposit and / or etch materials from the workpieces. Many current microfeature devices have interconnects and other very small sub-micron sized features (e.g., 45-110 nanometers) formed by depositing materials into small trenches or holes. One particularly useful process for depositing materials into small trenches and / or vias is electroplating. Typical electroplating techniques include plating processes that deposit copper, solder, permalloy, gold, silver, pl...

AI Technical Summary

Benefits of technology

[0007] The present invention provides electroplating reactors for processing seed layers, depositing materials directly onto barrier layers, and / or depositing materials onto microfeature workpieces in other applications. The reactors enable the use of an inert anode and a low conductivity processing solutions so that the reactors of the invention are not plagued by the flaking problems associated with using consumable anodes in high pH solutions. The reactors achieve this result by significantly reducing or eliminating oxidation of certain constituents of the processing solution to prolong its operating life. This reduces the operating costs of using the reactor because the tool does not need to be frequently shut down to change out the processing solution. A further benefit of reactors in accordance with the invention is that they are designed to operate within conventional power consumption ranges and still plate a uniform layer of material on a seed layer or directly on a barrier layer. The reactors also enable the use of high pH processing solutions in the same system. As a result, reactors in accordance with the invention are expected to further reduce the operating costs of electroplating seed layers, depositing materials directly onto barrier layers using low conductivity processing solutions, and / or using high pH processing solutions.

[0009] The support member provides several advantages for using a low-profile reactor. The support member contacts the ion exchange membrane to impart the desired contour or profile to the membrane. This prevents the membrane from having a shape that disturbs the electrical field or traps bubbles. The support member also directs a flow of the first processing solution over the ion exchange membrane and toward the processing zone, and the support member configures the electrical field in the first chamber. The support member enables the reactors to reduce the distance between the processing zone and the electrode in the second chamber so that less power is required to establish a sufficient electrical field compared to conventional reactors. Reactors in accordance with the invention accordingly enable the use of low conductivity, high pH processing solutions with conventional power supplies that are already widely used in plating tools.

Problems solved by technology

This reduces oxidation of constituents of the catholyte, which results in good quality deposits over a long bath life.

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