Wafer/Material Thickness Bow Metrology System

Wafer / Material Thickness Bending Measurement System

Sigmatech uses proprietary technology: Auto Positioning Back Pressure (APBP) to measure the thickness and bend of chips or materials.

In recent years, the newly developed white light optics WLCS (White Light Chromatic Sensing) can produce faster and more accurate measurements. The machine can combine two technologies on the same machine, and its application scope includes semiconductor packaging, chip manufacturing, solar chip manufacturing, special chip (Glass, Sapphire, SiC...) manufacturing, etc.

Back pressure APBP (Auto Positioning Back Pressure) technology: Using the pneumatic Wheatstone bridge principle, when the left probe in the right picture is measuring, the fluctuation of the object surface causes the change of air pressure. In order to balance the air pressure, the device connected to the encoder needs to move to release the pressure, so the change of the object's thickness can be detected. The measurement accuracy can normally reach ±0.1um or above. The left figure is a distance and voltage diagram (representing air pressure). It can be seen that this method will not contact the object to be measured because the back pressure is inversely proportional to the distance.
White Light Collimator (WLC) technology: uses a mercury lamp to generate white light. After passing through a lens, the white light is dispersed into different wavelengths of light with different focal lengths. The detector detects the wavelength with the highest reflection intensity on the surface, and the reference position of the object to be measured can be determined through calculation. After measuring with the upper and lower probes, the thickness of the object to be measured can be obtained. The white light method may be able to measure film thickness (um): that is, by detecting the wavelength of the second reflection after passing through the film, the film thickness can be calculated.