| Popis: |
The implementation of copper processing in semiconductor manufacturing has resulted in major process development and manufacturing challenges. A fundamental understanding of the copper plating processes used in manufacturing has been limited by the lack of in‐line methods for direct measurement and control of process chemistry. Plating bath chemistry adjustments and change‐out frequencies are currently determined using a combination of indirect electrochemical monitoring techniques, off‐line analyses of wafer metrology and analytical lab measurements. There have been a number of industry reports of major process startup delays, yield management problems and reliability issues as a result of these difficulties. A new in‐process mass spectrometry (IPMS) approach enables automated, real‐time measurement of both the inorganic components and organic additives in the copper electroplating chemistry as they change during production. The tool is not only capable of real time direct quantification of the copper, chloride, pH, and organic additives in the plating bath, but can also monitor additive breakdown byproducts as they occur during the production process. These breakdown products, as well as changes in the original bath constituent composition can be expected to have a major impact on process performance. We are now in the process of measuring longer term plating bath stability and chemistry changes in prototype applications in semiconductor fab manufacturing environments. The first results demonstrate improved process understanding and the potential for greatly improved process control. We will discuss the technical challenges that were successfully addressed in developing the IPMS capability for application to the copper plating process and the initial process data subsequently obtained. |
