Jul 16 2007
HORIBA Jobin Yvon has developed the DigiScreen, a new metrology tool capable of measuring thin films deposited on top of large area glass substrate used in the display industry.
Based on spectroscopic reflectometry, the DigiScreen provides film thickness in less than one second. Delivered to major display process chamber manufacturer for quality control, the DigiScreen has proved to be a reliable metrology tool that combines high throughput with accurate thickness uniformity over hundreds of points. 
DigiScreen: Fast Large Area Film Thickness Uniformity Measured by Spectroscopic Reflectometry
Sample size up to 2.5 m x 2.7 m can be accommodated on the DigiScreen. The sample is manually loaded on a vertical large area mapping stage tilted at an angle of ten degrees. A Quartz Tungsten Halogen (QTH) light source coupled to an optical fibre is focused onto the sample giving a spot size of 2 mm in diameter. A second optical fibre collects the light reflected from the sample. A 2048 pixels CCD coupled with a high resolution spectrograph, measures the reflected intensity. An integrated controller drives simultaneously acquisition and analysis of the data. The collected spectra is analyzed using HORIBA Jobin Yvon spectroscopic ellipsometry Delta Psi 2 algorithms. Delta Psi 2 software package provides a simple and powerful interface for production and research environments.
With a spectral range of 400 nm - 800 nm, the DigiScreen can measure films thickness from 100 nm to several microns. Materials such as SiN, SiON, a-Si(n+), a-Si(HDR, LDR), LTPS, c-Si, Silane based SiOx, TEOS have been successfully characterized. Comparative measurements between the DigiScreen and the FF-1000 (Large Area Spectroscopic Ellipsometer manufactures by HORIBA Jobin Yvon) gave similar thickness values within 0.26%.
The DigiScreen combined high throughput and accurate film thickness uniformity capabilities. It is the perfect metrology tool for quality control of large area display.