Photobase generator and photo decomposable quencher for high-resolution photoresist applications

Abstract

As the critical pitch continues to shrink for advanced technology nodes and the EUV tool is not yet mature, the demand for ArF high-contrast resist becomes stronger than ever. In this paper, we discuss the impact of photosensitive quenchers to lithographic performance. Two types of photosensitive quencher, photo-base generator (PBG) and photo decomposable quencher (PDQ), are studied for its ability to extend the life of immersion ArF lithography. With conventional photoresists using normal non-photosensitive quenchers, the aerial image was substantially linearly transferred to the acid image of the photoresist stimulated by photo acid generator (PAG). The new PBG or PDQ serves as one additional photosensitive component. Such photosensitive quencher changes its base level after exposure. Thus, it modifies the aerial image for better imaging performance. We will present and discuss the imaging results from various formulations of photosensitive quencher and variation in its concentration. The defect performance of these new approaches will also be characterized.

Effective resist profile control

“…In order to maintain the resolution, the main components of the resist, such as PAG 1,2,3 , photo-decomposable quencher (PDQ) 4,5 and ALG, should continue to be used. In such a boundary condition, we introduce new floatable PAG, floatable additives 6,7,8,9 , and new monomer groups to modify the profile without changing the basic formulation.…”

Understanding the onset of EUV resist chemical stochastics

“…This acid diffuses, primarily during the subsequent post-exposure-bake step, and causes deprotection of the polymer leading to the desired dissolution switch of the resist in the liquid developer. While there are other options to improve the performance of the photoresist including binding the PAG to the polymer [2][3][4][5] backbone and replacing the base with a photo decomposable quencher, [6][7][8][9][10] the main issue of resist chemical stochastics is that this is a multi-component system so distributions of molecules can lead to local variations in resist sensitivity and dissolution rate. 5,[11][12][13][14][15][16]…”