Develop methods for ensuring optimal process performance in a large scale, high volume, high flexibility manufacturing environment.
We develop metrology techniques, for in-process measurement of equipment and product (machinery control) and final-product process-level measurements (statistical process control).
Both functional testing and dimensional measurements are important aspects of a complete metrology plan. There will not be a one-size-fits-all metrology solution for all issues. We imagine a multi-tiered approach using super-resolution mechanical and optical techniques such as AFM and confocal microscopy and functional testing on a sampled set of product, and lower resolution techniques relying on digital imagery for defect detection and in-process dimensional measurements.
A key aspect of the work is to address the interface between tooling and parts, that is, how well does the part conform to the tooling that was used to create it. Various metrology concerns include the ability to measure bond quality, feature dimensions, defects and flaws, truth-to-mold, buried feature dimensions, layer thickness, and shrinkage. Also, we seek to correlate the part and mold dimensions and variations such as substrate warpage, curvature, pillar height and roughness to process conditions which created the parts and molds.
Some of our current research endeavors include:
Promulgation of metrology standards for microfluidic devices. Research page.
Examination of optical- and mechanical (e.g., AFM) - based approaches for in-process measurement.
Adaptation of nano-resolution methods to production inspection.
Development of typical process histories and statistical performance. Research page.
In-process, real-time product-level feedback for variation control.
Development of performance standards.
Propagation of variation through multilayer processes. Research page.
We investigate the importance of both small scale errors (at the individual part feature level) and large scale device distortions.