ASML to supply EUV pellicle with over 90% transmittance 

ASML will start supplying pellicles used in extreme ultraviolet (EUV) systems with transmittance of over 90% this year.

ASML Korea marketing manager MyoungKuy Lee said at an SMC Korea seminar that the company will begin production of pellicles with over 90.6% transmittance rate.

The pellicles have secured 400watt power durability, Lee said. They were developed with Teradyne.

The Netherlands-based fab equipment maker developed a polysilicon EUV pellicle for the first time in 2016. At the time, it had transmittance rate of 78%.

It developed ones with a rate of around 80% in 2018, and another with over 85% in 2020.

Pellicles are used to protect the mask from dusts. However, a unit costs around 20 million won to 30 million won ($26,000).

EUV systems has the light reflected from a mirror to reach the wafer, unlike previous systems that used argon fluoride lasers that were shot in alight from the top to the wafer.

This required to the pellicles used for EUV systems to be more transparent to make sure the light isn’t weakened when it passes through them reach the wafer.

Samsung and TSMC had previously said it will need pellicles with over 90% transmittance rate for them to consider using them.

These companies have used EUV systems without pellicles despite the risk of dust settling due to the unsatisfactory transmittance rate.

ASML’s pellicles will be made by Japan’s Mitsui Chemical. The pair signed a collaboration agreement on EUV pellicles back in 2019.

South Korean firms FST and S&S Tech are also developing EUV pellicles. Last year, FST had said it plans to launch a silicon carbide based pellicle with over 90% transmittance within the first half of this year.