Two Technologies in One Tool
SSEC has combined two process techniques in a single system to provide superior results at the lowest cost of ownership. Immersion processing is used with heated solvents for longer cycle time processing, while the single wafer spray process is used as a final processing step. Because each system is a sealed, nitrogen purged system, with separate solvent recirculators, solvent consumption, emissions, and disposal are kept to an absolute minimum.
Batch Immersion Processing Each wafer is soaked under precisely controlled conditions in a heated, recirculated, solvent immersion bath. Typical soaking times are on the order of 20 minutes, with the robotics system automatically shuttling wafers in and out, based upon the downstream process times and number of single wafer spray stations. After the initial soaking time for the first wafer, this sequencing maintains a high number of wafers per hour per square foot, with systems available to 100 wafers per hour.
Single Wafer Solvent Spray Processing
Following the soak, the solvent wet wafer is transported to a single wafer spin process station for lift off processing. With resist softened from the soak, metals or resist are rapidly removed with a high pressure process that includes needle and fan spray, both with heated solvent solutions at pressures up to 3,000 psi. Backside cleanliness is maintained with either backside rinses or programmable backside spray dispense arms. Spray configurations for both fan and needle spray are under per-step program control. The high pressure spray is fully controlled through a flow rate monitoring system, with per wafer collection of data. The flow data can be passed through an SECS GEM link. By monitoring the flow rate, the software can detect a clogged nozzle, clogged filters, leaks in plumbing or pumps, and other faults. The high pressure spray process is enhanced through the utilization of point-of-use, high pressure solvent heaters. These ETL listed heaters will heat the solvent to the chemistry flash point. |