Recently, Semiconductor Engineering magazine discussed the current status and future directions of mask manufacturing with four experts, including Harry Levinson, chief lithographer at HJL Lithography, Aki Fujimura, CEO of D2S, Ezequiel Russell, senior director of mask technology at Micron, and Christopher Progler, executive vice president and chief technology officer of Photronics.
Mask cost status and challenges
Changes in cost ratio
Russell: The proportion of mask in total cost has decreased relatively, but due to EUV, the life of mask is shortened and replacement is frequent, so the total cost of the whole set of masks is still high.
Levinson: In high-end logic design (cost of hundreds of millions of dollars), mask cost of 10-20 million US dollars is acceptable; low-end market (automotive/consumer electronics) is extremely sensitive to mask cost.
EUV increases costs
Progler: EUV mask costs remain a huge concern, and customers are more concerned about delivery speed rather than price.
Russell: EUV masks are used less frequently and need to be replaced more frequently, turning masks from a one-time investment into a recurring cost.
Low industry acceptance
Progler: "No one really accepts the current mask cost." Optimization strategies include improving yield, reducing EUV blank mask material costs, and using computing tools to reduce experimental waste.
Fujimura: Mask quality is linked to wafer performance (e.g., improving mask CD uniformity can improve wafer quality), and new technology investment (e.g., curved ILT) may be worthwhile.
The disruptive impact of high numerical aperture EUV
Impact of large-size masks
Progler: If 6×12-inch masks are used, all equipment such as mask writers/etchers/inspection tools need to be redesigned.
Fujimura: The infrastructure has changed completely, which is a major transformation. It is necessary to evaluate whether the wafer-level benefits are worth the huge investment.
Comprehensive changes in the supply chain
Levinson: High numerical aperture brings new challenges, such as sub-resolution assist features (SRAF) printing starts at 4.5 nanometers, which requires improved mask resolution; customized absorption layer stacking will subvert the current standardized process.
Progler: High numerical aperture requires deformation exposure, splicing and more stringent pattern fidelity, film and substrate flatness.
Unified platform impact
Russell: ASML's unified platform strategy requires high/low numerical aperture EUV to use 6×12-inch masks, and mask factories need to replicate the entire production line (inspection/etching/writing tools), which increases capital burden.
Risk of industry differentiation: Unprepared companies may be excluded from the next generation of lithography machines.
Directions of technological change in the next five years
Resolution roadmap controversy
Progler: Mask resolution demand may stagnate. If wafer-level value cannot be improved, suppliers need to turn to other differentiated competition (non-resolution priority).
Curve process deepening
Levinson: Surface features will subvert data formats, defect detection and other links.
Fujimura: Curved ILT has a profound impact on mask manufacturing and needs to be continuously optimized.
AI-driven ecosystem
Progler: AI's ability to predict lithography results may subvert the working mode, and high-performance computing to build a model-driven ecosystem is a key opportunity.
Russell: ASML's unified platform forces the entire industry to turn to large-size masks, and unprepared companies face the risk of elimination.
Source: Content compiled from semiengineering
Reference link: https://semiengineering.com/disruptive-changes-ahead-for-photomasks/
