For latest results, please see Project results.
Today there are no available tools or procedures for quality monitoring industrial deposition of PZT thin films. For piezoMEMS, complete devices have to be fabricated and then tested. For cost effective production it is essential to evaluate the film quality at an early stage in production, before more costly process steps like e.g. back side etching are performed.
Quality monitoring can be split into methods that are related to the quality of the morphology, e.g. in-situ XRD or ellipsometry and electrical and electromechanical test methods that are related to the ferroelectric and piezoelectric properties of the PZT. The first group of test equipment gives excellent feedback on the crystallinity, film thickness and the refraction index, whereas the second group would monitor the essential properties directly related to the device performance, e.g. d33, dielectric constant and displacement.
For in-line quality monitoring of the PZT deposition process in a production facility the piezoelectric coefficients must be monitored directly in high throughput at wafer level. This has never been done before. piezoVolume will rely on the DBLI technology, as it is known for high resolution (less than 1 pm), speed and good repeatability for small sample sizes. Hence, aixACCT will develop a tailored DBLI tool for quality control suitable for 150 mm and 200 mm wafers in high volume production.
The DBLI tool will be developed to meet the following testing needs:
Published April 22, 2010
DBLI tool from aixACCT
The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2010-2013) under grant agreement n° 229196