Designed for optoelectronics applications, the AF 32 glass introduced by Schott North America Inc. is suitable for use in the wafer-level chip scale packaging and optics markets. Its coefficient of thermal expansion matches that of silicon, helping to prevent warp during the manufacture of complex assemblies and during reflow, when a wafer-level chip scale packaging imager is attached to a printed circuit board. Thicknesses range from 0.1 to 1.1 mm, and the fire-polished surface of the glass achieves a roughness value below 1 nm rms, eliminating the need for fine mechanical polishing. AF 32 is an aluminoborosilicate glass that is alkali-free in synthesis and is easy to cut and dice. The company says that it exhibits high luminous transmittance and good cosmetic qualities.