Closed loop residual gas analyzer process control technique
View Patent ↗A technique for use in fabricating an integrated circuit are disclosed. The method generally begins by performing an operation on a wafer using a fabrication tool. Next, volatiles are desorbed from the wafer. The desorbed volatiles are sampled and raw spectral data indicating the content of the desorbed volatiles is generated. The raw spectral data is subjected to a spectroscopic analysis. An operational parameter of the fabrication tool is then modified responsive to the result of the results of the spectroscopic analysis. In one particular aspect of the invention, a controller receives the raw spectral data and processes the raw spectral data to determine the presence of a residual material on the wafer. The controller then controls the process flow operation to reduce the amount of the residual material on the wafer responsive to the results of processing the raw spectral data. Other aspects of the invention include the apparatus implementing the process flow and the controller itself.
1. A process for use in fabricating an integrated circuit, comprising:
performing an operation on a wafer using a fabrication tool;
generating desorbed volatiles from the wafer after performing the operation;
sampling the desorbed volatiles;
generating raw spectral data from the sampled desorbed volatiles, the raw spectral data indicating the content of the desorbed volatiles;
performing a spectroscopic analysis of the raw spectral data; and
modifying an operational parameter of the fabrication tool responsive to the result of the results of the spectroscopic analysis.
2. The process of claim 1 , wherein performing an operation on a wafer using a fabrication tool includes performing a chemical mechanical polishing operation, a plasma etching operation, or a wafer cleaning operation.
3. The process of claim 2 , wherein modifying the operational parameter of the fabrication tool includes increasing a rinse time or increasing a polishing time of the chemical mechanical polishing operation.
4. The process of claim 1 , wherein modifying the operational parameter of the fabrication tool includes increasing a rinse time of a chemical mechanical polishing operation, increasing a polishing time of a chemical mechanical polishing operation, resetting a scheduled maintenance time.
5. The process of claim 1 , wherein generating desorbed volatiles from the wafer after performing the operation includes heating the wafer in a vacuum chamber to generate desorbed volatiles.
6. The process of claim 5 , wherein heating the wafer in a vacuum chamber includes heating the wafer in a lamp degas chamber or a pedestal temperature controlled process chamber.
7. The process of claim 1 , wherein sampling the desorbed volatiles includes sampling the desorbed volatiles with a residual gas analyzer.
8. The process of claim 1 , wherein modifying the operational parameter includes issuing a new APC plan.
9. The process of claim 1 , further comprising at least one of:
storing the results of the spectroscopic analysis;
performing a trend analysis on the results of the spectroscopic analysis; and
performing a variability analysis on the results of the spectroscopic analysis.