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Semiconductors require ever increasing purity in fluids that come in contact with the devices to reduce the defectivity during the manufacturing process. Defect control is extremely critical and continues to be one of biggest challenges in lithography processes for integrated device manufacturers (IDMs) as the critical dimension (CD) size shrinks . Any defect could result in an unusable device, resulting in a financial loss for the IDMs. Particularly in 193nm lithography processes, there have been widespread occurrences of various defects in the coated films, and many factors could play a role in defect formation. For example, photoresist and BARC coating defects could be affected by the dispense process, cleanliness of the materials, and filtration process.
Particle removal filters are used in almost every process step where a liquid comes in contact with a wafer. Implementation of polymer membrane-based microfiltration in the photochemical manufacturing process effectively improves the cleanliness of the materials. Furthermore, in today’s state-of-the art semiconductor fabs, an extra filtration step at the point of dispense on the coater module is adopted to further minimize coating defects by providing particle/bubble-free photochemical dispense on the wafer.
With the continuous demands for defect reduction and high productivity, Entegris has developed a new, highly retentive 5nm rated asymmetric ultrahigh molecular weight polyethylene (UPE) filter to address these demands particularly in advanced lithography processes. The purpose of this application note is to provide data to show the performance of 5nm asymmetric UPE filters and its effectiveness of reducing the wafer defects for various lithographic processes.