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Design of Experiments
Figure 2: An example of factorial design of experiments (DOE) in printed circuit manufacturing to minimize innerlayer shifting during lamination.
The second experiment, in Figure 3, uses optimizing photoresist exposure, developing and etching to provide the highest production yield. The variable and levels were a full factorial design of three variables at three levels (center point):
1. Exposure energy in mjoules: 70, 50 & 30
2. Developer speed in inches per minute: 45, 40 & 35
3. Etcher speed in inches per minute: 45, 40 & 35.
The variables were chosen with the center point being the current production process: 50 mjoules, 40 in/min developer and 40 in/min etcher. The highest yield was 95% using slower developer speed, lower exposure intensity, and the slower etcher. Analysis shows that the developer speed has the greatest effect on yield and interacts with etcher speed.
Figure 3: An example of factorial design of experiments (DOE) in printed circuit manufacturing to optimize yield in exposure, developing and etch.
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