For decades the process of spin coating has been used to apply a resist film over a silicon wafer as part of the broader process of microcircuit fabrication necessary to produce high yielding silicon wafers.
BEOL semiconductor tools for WLCSP (Wafer level chip scale packaging) take advantage of many lithographic techniques utilized in the manufacture of the chip in the Front End of Line (FEOL).
As the aqueous develop is essentially an etch, it is important that corrosion rather than erosion be the only process so that develop “hot spots” can be avoided.
The primary difficulty in coating substrates of pyroelectric materials is that the materials will build substantial charges leading to very high voltages when heated.
In the formation of both gold bumps and copper pillars it is required to contain the “plated up” structure within a “mold” of polymer material.
Small footprint fully automated single wafer reflow processing using flux and flux cleaning spinners robotically coupled to atmospheric controlled reflow hot plates.