The AF 32 glass is designed for leading-edge opto-electronics, image sensor packaging, WLO, and MEMS applications. It matches the CTE of silicon, which helps prevent warp during the manufacture of complex assemblies and during reflow, when a WLCSP imager is attached to a printed circuit board. These properties enable manufacturers to use thinner wafer cover glasses and replace the back glasses on their packages with plastic. The glass comes in thicknesses ranging from 0.1 to 1.1 mm. A statistic process control system enforces a tight thickness tolerance in the AF 32 glass, so a total thickness variation of ±5µm can be achieved right from the tank. The AF 32’s fire-polished surface possesses a roughness value below 1 nm RMS, ensuring that costly fine mechanical polishing is not required. AF 32 is an aluminoborosilicate glass that is alkali-free in synthesis. SCHOTT North America Inc., Elmsford, NY; www.us.schott.com .