TSMC Develops the World’s First Dry-Clean Technique for EUV Mask, Creating an Accumulated NT$2 Billion of Improvement Effect

TSMC leads the world to adopt EUV lithography technology to help customers rapidly realize advanced product design. To achieve the high yield of EUV process and fulfill the mission of green manufacturing, TSMC develops the world’s first environmental-friendly “Dry-Clean Technique for EUV Mask” to replace the traditional clean process. By means of fall-on analysis and contamination source elimination, the fall-on count of each 10,000 wafers decreased from hundreds of particles to single-digit particles, achieving 99% of reduction rate. Since its introduction, the amount of water saving and chemical usage saving has reached about 735 metric tons and 36 metric tons, respectively.

Analyze, Track, and Eliminate Fall-on Source, Protecting Product Quality

Depending on process requirements, EUV photomask is divided into two types – with pellicle and without pellicle. TSMC has chosen EUV mask without pellicle to enhance optical transmittance, thus reducing energy loss during exposure process. To resolve the fall-on issue, TSMC’s Quality and Reliability Organization has collaborated with Technology Development and Operations Organizations to jointly develop the fall-on analysis technique since 2018.

TSMC develops the “Dry-Clean Technique for EUV Mask” with innovative thinking. Instead of using traditional wet clean process with ultrapure water and chemicals, fall-on particles are rapidly removed by such a dry clean technique. Meanwhile, the fall-on source is precisely located by sub-nanometer analysis technique and therefore contaminations can be excluded thoroughly. With persistent tests and optimization, the fall-on particle reduction rate achieved more than 99% in 2020.

TSMC’s Dry-Clean Technique for EUV Mask

Dry Clean Technique Increases Resource Utilization Efficiency and Creates NT$2 Billion of Improvement Effect

With this innovative Dry-Clean Technique for EUV Mask, TSMC not only reaches the goal of leading the industry to use EUV process for mass production but also greatly enhances resource utilization efficiency. In addition to the saving of ultrapure water and chemicals, the frequency of mask RR and duration are reduced substantially based on the production cycle time control and management system. Since its introduction in 2018, the duty cycle of EUV mask has increased more than 80%, and the lifetime for advanced process EUV mask has also extended, generating an accumulated NT$2 billion of improvement effect.

In 2019, TSMC further developed the automation of the Dry-Clean Technique for EUV Mask. The automatic mass production system was introduced to all 12-inch wafer fabs in January of 2020. Currently, TSMC’s Quality and Reliability Organization continuously develops the analysis and clean technique for tinier fall-on particles, which lays a solid quality management foundation for future advanced process and keeps the commitment of green manufacturing.

Development Timeframe of Dry Clean Technique for EUV Mask in TSMC