Multi Trigger Resist

Description

Keywords: EUV lithography, photoresist, molecular resist, multi-trigger resist, chemical amplification, crosslinking

The development of a photoresist to support EUV lithography in high volume manufacturing for the next node and beyond remains a challenging issue, with no material currently meeting the combined resolution, sensitivity, and line width roughness (RLS) requirements, and additional stochastic defectivity issues yet to be addressed. Whilst traditional chemically amplified resists will likely support the initial insertion, a wide range of materials options are being examined for future nodes [1–3], aiming to identify a photoresist that simultaneously meets RLS and defectivity requirements.

Irresistible Materials (IM) is developing novel resist systems based on the multi-trigger concept. In a multi-trigger resist multiple elements of the resist must be simultaneously activated to enable the catalytic reactions to proceed. In high dose areas the resist therefore behaves like a traditional CAR, whilst in low dose areas, such as line edges, the reaction is second-order increasing the chemical gradient. Effectively there is a dose dependent quenching-like behaviour built in to the resist, enhancing chemical contrast and thus resolution and reducing roughness, whilst eliminating the materials stochastics impact of a separate quencher.

The multi-trigger material previously presented [4, 5] consists of a base molecule and a crosslinker, which represent the resist matrix, together with a photoacid generator (PAG). MTR2 showed 16 nm half pitch lines patterned with a dose of 38 mJ/cm2, giving a LER of 3.7 nm on the NXE3300 [4]. Since then, research has been undertaken to improve this resist. In particular we are focusing on improving resist opacity and present initial results for the MTR262Z(D) resist formulation here. Figure 1 shows semi-dense 15.8 nm CD lines patterned using the NXE EUV Scanner in MTR262Z(D) at a halfpitch of 20nm, and dose of 13mJ/cm2. Figure 2 shows lines with a CD of 12 nm patterned at 22.5 mJ/cm2 on a 16 nm halfpitch.

Period	12 Jun 2019
Event title	EUVL Workshop
Event type	Workshop
Location	Berkeley, United States, CaliforniaShow on map
Degree of Recognition	International