Precise thickness profile measurement insensitive to spatial and temporal temperature gradients on a large glass substrate

2020 ◽  
Vol 59 (20) ◽  
pp. 5881
Author(s):  
Jungjae Park ◽  
Hiroki Mori ◽  
Yoon-Soo Jang ◽  
Jonghan Jin
2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Xiangyu Guo ◽  
ChaBum Lee

Abstract This paper presents a novel thickness profile measuring system that measures double-sided thin pipe wall surfaces in a non-contact, continuous, cosine error-free, and fast manner. The surface metrology tool path was developed to align the displacement sensors always normal to the double-sided surfaces to remove cosine error. A pair of capacitive-type sensors that were placed on the rotary and linear axes simultaneously scans the inner and outer surfaces of thin walls. Because the rotational error of the rotary axis can severely affect the accuracy in thickness profile measurement, such error was initially characterized by a reversal method. It was compensated for along the rotational direction while measuring the measurement target. Two measurement targets (circular and elliptical metal pipe-type thin walls) were prepared to validate the developed measurement method and system. Not only inner and outer surface profiles but also thin-wall thickness profiles were measured simultaneously. Based on the output data, the circularity and wall thickness variation were calculated. The thickness profile results showed a good agreement with those obtained by a contact-type micrometer (1-µm resolution) at every 6-deg interval. The uncertainty budget for this measuring system with metrology tool path planning was estimated at approximately 1.4 µm.


2008 ◽  
Vol 46 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Young-Min Hwang ◽  
Sung-Won Yoon ◽  
Jung-Hwan Kim ◽  
Souk Kim ◽  
Heui-Jae Pahk

1998 ◽  
Vol 508 ◽  
Author(s):  
Kiyoshi Yoneda

AbstractSince being introduced to the production line in 1996, replacing the first generation a-Si TFT line, low-temperature poly-Si production technology aimed at manufacturing small and medium size LCD products has improved steadily corresponding to customers' requirements for rapid growth of the DVC and DSC markets. In the future, this production technology must progress to actual industry technology levels in order to cope with production applied not only to large size displays, which have a major market share in the present display market, but also to a large glass substrate, which effectively cuts the cost of products, although improvement of production yield and productivity in terms of pursuing cost reduction must be proceeded.This paper has described existing problems of inherent low-temperature poly-Si TFT processes and their relating additional processes in present production methods. We have also discussed updating production technologies. To cope with production for a large size display, it is necessary to establish fabrication technology of higher performance TFTs with electron mobility larger than 200cm2/V s. We believe that one key technology is to fabricate a large-scale and highly-uniform recrystallized poly-Si film with smooth surface morphology as well as precisely-controlled grain size in production. To cope with production using a large glass substrate, it is essential to develop ELA equipment with laser power greater than 200W.


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