Warping of BGA substrates

Substrate heating caused by ion bombardment. This effect is inherent in RF plasma processing as a result of too little active oxygen species.

Cirrus 80 provides a high density of active and low energy ionized species with no applied RF bias. As a result, substrate heating due to ion bombardment is minimal.

Non-uniform cleaning from edge to center of substrate if processed in magazines

High pressure RF and DC plasma processes have relatively short mean-free paths. This means that the edge of the BGA strips get substantially greater plasma exposure than the center of the strip. Frequently, contact angles are 30 degrees or more at the center of the strip, even after contact angle at the edge has dropped below 10 degrees.

Cirrus 80 excels at low pressure (less than 10 mTorr) plasma processing. At these pressures, the mean-free path of activiated and ionized species is much greater. As a result, diffusion of the plasma into magazines occurs readily, giving uniform cleaning across the substrate.

Degradation (burning) of BGA polymer substrates

RF systems are inefficient producers of active and ionized species. As a result, much of the expended power is dissipated in substrate heating.

Cirrus 80 yield highly efficient production of activated and ionized species. In this case, the plasma is used effectively for cleaning the substrate with minimal temperature rise.