Lithography Filtration for Semiconductor Manufacturing

Enabling Shrinking Device Geometries

Lithography is the key technology driver for the semiconductor industry.

The industry's continued growth is a direct result of improved lithographic resolution. The complexity of today's fabricated semiconductor chips necessitates the use of numerous microlithographic steps to achieve multilevel circuits.
Several key industry transitions have put an increased burden on contamination control in every aspect of the microlithography process. These transitions include the implementation of DUV photoresist, adoption of top and bottom antireflective coatings, the trend towards thinner coatings and the use of immersion lithography.

Each step introduces the possibility of deleterious particulate contamination, microbubble void defects and metallic contamination onto the wafer surface. The removal of particles that are smaller than the feature size is imperative to prevent circuit failure. Eliminating any air and preventing the formation of microbubbles is critical to reducing coating defects and increasing yields.

Selecting the appropriate materials to minimize metallic contributions while optimizing dispense performance is essential for optimizing the coating process.


Semiconductor overview
Semiconductor - Applications
Semiconductor - Chemical
Semiconductor - CMP
Semiconductor - Gas Filtration and Purification
Semiconductor - Lithography
Semiconductor - Ultrapure Water
Semiconductor - Wastewater Treatment
Photolithography Filtration for Semiconductor Manufacturing Application LiteratureFind a Pall Representative for Answers to Ordering Questions

The use of bulk filters by photoresist manufacturers and point-of-use (POU) dispense filters by end users prevents the deposition of unwanted particles onto the wafer surface during the fabrication of the semiconductor chips.

The International Technology Roadmap for Semiconductors, sponsored by five leading chip manufacturing associations, has cited the removal of particles 20 nm as critical for advanced semiconductor devices. The reduction of feature sizes to 22 nm or smaller has led to the offering of tighter membranes to ensure the removal of yield reducing particles.

The method of delivering lithographic chemicals to the wafer surface is best accomplished by a precision dispense system. The point-of-use filter is an integral part of the dispense system, therefore careful selection of this filter is necessary to reduce defects on the wafer surface. In addition to particle and gel removal, minimization of microbubble formation, reduced chemical consumption and good compatibility are all key areas for point-of-use (POU) filter selection.

Fortunately, several membrane materials are available for filtration of the variety of lithographic chemicals needed in the fabrication of today's and  tomorrow's integrated circuits.
Click to expand/collapse this sectionLithography Flow Schematic and Filter Recommendations
Click to expand/collapse this sectionTechnical Issues in the Filtration of Lithographic Chemicals
Click to expand/collapse this sectionRemoval Efficiency
Click to expand/collapse this sectionGel Removal
Click to expand/collapse this sectionEase in Venting (Minimal Microbubble Production)
Click to expand/collapse this sectionLow Operating Pressure
Click to expand/collapse this sectionReduced Chemical Waste
Click to expand/collapse this sectionMinimal Metal Contamination
Click to expand/collapse this sectionConclusion