Presentation
4 March 2019 Stress metrology for flexible and flat-panel display manufacturing (Conference Presentation)
Wei-Chun Hung, Raphael Morency, Wojtek J. Walecki
Author Affiliations +
Proceedings Volume 10925, Photonic Instrumentation Engineering VI; 109250R (2019) https://doi.org/10.1117/12.2511183
Event: SPIE OPTO, 2019, San Francisco, California, United States
Abstract
The photo-elastic stress metrology is well known measurement technique widely used in mechanical engineering applications since at least 1940 [1]. Its use in semiconductor manufacturing has been limited since the direct measurements of the stress in silicon are complicated by relatively low values of stress-optic coefficient and need of use on NIR array detectors. The advent of flexible electronics and wide spread of use of PI films as passivation layer give opportunity to take advantage of very strong stress induced birefringence effect in PI for practical application. Here we present practical tool enabling measurement of stress in PI films with resolution down to 1 MPa. The optical system comprises of (light emitting device) LED panel (light source), polarization components, color filters and camera. Due to the birefringence caused by the stress, the sample changes the light into the elliptically polarized light. To analyze the elliptically polarized light and to eliminate the ambiguity when unwrapping the phase, we employed three (550 nm, 589 nm, and 632 nm) placed directly in front of the camera. We demonstrate performance of this system for flat panel displays having dimensions up 185 cm x 150 cm (G6). Discuss throughput and repeatability of this metrology. We also discuss scalability of this metrology. [1] K. Ramesh, “Digital Photoelasticity Advanced Techniques and Applications,” Springer, 2000.
Conference Presentation
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Wei-Chun Hung, Raphael Morency, and Wojtek J. Walecki "Stress metrology for flexible and flat-panel display manufacturing (Conference Presentation)", Proc. SPIE 10925, Photonic Instrumentation Engineering VI, 109250R (4 March 2019); https://doi.org/10.1117/12.2511183
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KEYWORDS
Metrology

Flat panel displays

Manufacturing

Birefringence

Cameras

Mechanical engineering

Near infrared

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