Process monitoring system for real time statistical process control

A process control and data collection system for wafer fabrication process SPC, and comprising:

• a) a production control computer connected to a RS 485 network through a RS 485 adapter,
• b) a RS 485 to digital converter connecting control data from the RS 485 network to each wafer fabrication process machine,
• c) an analog to RS 485 converter connecting process parameter data from the wafer fabrication process machinery to the production control computer by means of the RS 485 network,
• d) said process parameter data from the wafer fabrication process machinery providing real time process data,
• e) said real time process data compared to SPC limits in the production control computer to determine a probability of yield from the process,
• f) adjustments made to the process depending upon the real time process data as compared to the SPC limits and the probability of yield from the process.

A method for real time process control by means of a process control computer connected to wafer fabrication machinery through a network, and comprising:

• a) collecting process parameter data by a production control computer connected to one or more wafer process machines by means of a network,
• b) storing real time process parameter data into a data base,
• c) computing an average value for each parameter of each product batch,
• d) storing said average values in an historical data file,
• e) determining process control limits from said historical data file,
• f) monitoring wafer fabrication process parameters and comparing to said process control limits.