High Precision Dispense System
Presisely controlled dispensing of photoresist is one of the key process steps in photolithography. Beside basic requirements like a bubble free dispense, the accuracy and flowrate profile influence the uniformity of a coating. Up to date, high precision dispensing was an exclusive domain of positive displacement pump-systems. SUSS MicroTec recently introduced a pressure based dispense system, which breaks into this area. A dispense volume repeatability of ± 1 % (3 σ) and accuracy of ± 2 % was made possible by means of sophisticated monitoring and control mechanisms. Furthermore a flow-sensor located at the latest possible point allows for monitoring the real flow and controlling the system accor-dingly. Software algorithms act as back bone of the system performance. The system can be used to dispense chemicals with viscosities from 1 cps to 10,000 cps.