Metrosemi - Model FLX 2320S -Wafer Stress Laser Scanner
The FLX-2320-S determines stress by measuring the curvature change of pre- and post- film deposition. It can measure film stress from -65ºC to 500ºC at a heating rate up to 30ºC/min. Stress variation with temperature is able to be used to characterize film properties, such as moisture concentration, phase changes, thermal expansion, volume changes, and plastic deformations. Other characteristics of the instrument include: – Dual wave lengths – Calculation of biaxial modules of elasticity, linear expansion coefficient, stress uniformity and file subtraction – Calculation of water diffusion coefficient – 2-D and 3-D view of wafer topography – Wafer size: 75 – 200 mm – Measurement temperature: from -65ºC to 500ºC – PC base controller – Speed: 5 sec for 150 mm wafer – Minimum scan step: 0.02 mm – Maximum points per scan: 1250
FLX-2320 is a thin film stress machine. A laser scanner is used to measure the changes in the radius of curvature of the substrate caused by the deposition of a thin film on the wafer. This is accomplished by first measuring the wafer curvature before the film is deposited and then re- measuring the curvature after the film is deposited. A well known mathematical relation is then used to calculate the stress of the thin film.