The Importance of Quick Dump Rinsing in Semiconductor Manufacturing

After chemical treatment of semiconductor wafers for cleaning, etching or stripping applications, or MEMS device KOH/HF etching applications, the process chemicals should be completely removed from the surface in order to stop the chemical reaction and take away chemical residues. Chemistry is still covering the wafer surface, in particular within recess structures of the topology (moats, trenches) resulting in continuation of the chemical process outside the bath. This is critical for etch applications, since over-etching might occur destroying the pattern and causing significant yield loss. Custom plastic tanks, PFA tanks are the common choices for quick dump rinsing steps.

The primary objectives of effective rinsing processes after all chemical steps are:

  1. To quickly and effectively stop the chemical reaction on the surface after the wafers have been removed from the bath.
  2. To fully remove chemical and contaminant residues from the wafer, which are carried over from the chemical bath without ANY impact on the wafer surface.
  3. To take off particulates from the wafer before the next chemical step or drying.

Basically, three types of rinsing are used in semiconductor manufacturing, depending on the tool type and application:

  • Overflow rinsing: immersion of wafers into a rinse bath with continuous introduction of water from the bottom of the tank and overflowing at the top rim.
  • Spray rinsing: Dispense of ultra pure water through spray nozzles directly onto the wafer at variable flow, pressure or temperature in a single pass mode (standard process of single wafer equipment)
  • Quick dump rinsing: a combination of the above for wet benches consisting of placing the wafer into an overflowing rinse tank, dump the ultra pure water in a very fast manner and refill the tank by spray and /or fill from the bottom.

To better equip Quick Dump Rinsers, Imtec has developed the Imtec Quick Dump Rinse (QDR) valve, custom designed to improve the rinsing process. Please also check out the Megasonic Quick Dump Process Recommendations.