The objective of the project was to significantly reduce VOC emissions of our ACT I photoresist stripper solution and also to reduce the total volume of ACT I solution used in Fab 2A's wafer processing operation. The ACT I solution historically has been one of the larger contributors to Fab 2A's VOC emissions. The solution is volatile and therefore evaporations losses are significant. The ACT I solution is used in wet baths in various production areas to remove photoresists and to clean product wafers.
In January 1993 the first wet hood was upgraded with specially designed covered tanks that reduced evaporation losses. At the beginning of April 1993 three (3) additional sinks were also upgraded so that the total Sony Fab 2A emission of ACT I VOCs could be reduced by approximately 88%.
Also at the beginning of April improved chemical changeout procedures were implemented. Extensive studies were completed that confirmed that by using an alternating clean / dirty bath procedure the ACT I bath life could in effect be extended from 15 lots to 50 lots. This improved changeout procedure resulted in approximately a 30% reduction in chemical usage and a $45,000 annual cost savings.
ACT I VOC emissions were reduced by 88% (approximately 14,000 lbs/yr.) and total chemical usage was reduced by approximately 66% (40,000 lbs/yr.). Excellent performance by all resulted in goals of the project being exceeded in a very timely manner.
Details of Reductions
Additional Information :
project was approximately $70,000. Pay back for the project was six months.