content_image/907384.jpg content_image/907382.jpg content_image/907383.jpg
imaging polymer. The resists were spin coated onto respec› tive HMDS-primed wafers. The wafers were baked on a hot plate at 110° C. for 1 minute. The resist-coated wafers were exposed at 25 kV on ElectronCure™-200M flood exposure tool manufactured by Electron Vision Group. After expo› sure, resists were baked at 110° C. for 1 minute before being developed with 0.263 N TMAH for 60s. The following table lists the doses to clear large square exposed with different DMPHS PFBUS loadings. 

<img src='content_image/907384.jpg'>

## Resist with Mixed Acid Generators (DMPS PFBUS and DMPHS PFBUS) According to the Invention 

Resist formulations were obtained in the manner of Example 4 except that a combination ofDMPHS PFBUS of Example 1 and DMPS from Example 2 was substituted for TPS TRF. The loading of the acid generators is indicated in the table below based on the weight of the imaging polymer. 

The resists were spin coated onto respective HMDS› primed wafers. The resist-coated wafers were baked on a hot plate at 110° C. for 1 minute. The resist-coated wafers were exposed using an IBM-built 25 kV Gaussian-beam system (FELS). After exposure, resists were baked at 110° C. for 1 minute before being developed with 0.263 N TMAH for 60s. The following table lists the doses to resolve 150 nm 1/s images with different DMPS PFBUS and DMPHS PFBUS loadings and image profiles. 

<img src='content_image/907382.jpg'>

## Resist with Mixed Acid Generators (TPS TRF and DMPHS PFBUS) According to the Invention 

Resist formulations were obtained in the manner of Example 4 except that a combination ofDMPHS PFBUS of Example 1 and TPS TRF was substituted for TPS TRF. The loading of the acid generators is indicated in the table below 

## EXAMPLE6 

## EXAMPLE 7 

based on the weight of the imaging polymer. The resists were spin coated onto respective HMDS-primed wafers. The resist-coated wafers were baked on a hot plate at 110° C. for 1 minute. The resist-coated wafers were exposed using an IBM-built 25 kV Gaussian-beam system (FELS). After exposure, resists were baked at 110° C. for 1 minute before being developed with 0.263 N TMAH for 60s. The follow› ing table lists profiles for 150 nm and 200 nm 1/s images with different TPS TRF and DMPHS PFBUS loadings at both 1.5 µC/cm 2 and 2.0 µC/cm 2 . 

<img src='content_image/907383.jpg'>

A study of resist performance characteristics ( e.g., dose latitude, resist profile as related to unexposed dissolution, sensitivity, and E$_{0}$/Ecn) was performed to determine an optimal composition using the imaging polymer of Example 3 and the combination of acid generators of Example 7. From this study, it appears that a composition having 0.28 wt.% TBAH, 7 wt.% TPS TRF and 7.37 wt.% DMPHS PFBUS provided the best overall performance (31 % dose latitude, 7.4 A/second unexposed dissolution rate, an E$_{0}$ / Es,ze of 0.74, and a sensitivity of 3.9 mC/cm 2 with vertical resist profiles). 

Wafers coated with this formulation in the manner of Example 4 were then imaged on a soft x-ray (1.1 nm wavelength) lithography tool from JMAR Technologies Inc. Using soft x-ray, the resist of the invention required a dose of less than 15 mJ/cm 2 . Commercial resists would have an exposure dose requirement in the range of 50-90 mJ/cm $^{2 }$for the same soft x-ray exposure process. 

What is claimed is: 

1. A resist composition comprising (a) an imaging poly› mer, and (b) a radiation sensitive acid generator component, said radiation sensitive acid generator component compris› ing: 

(i) a first radiation sensitive acid generator selected from the group consisting of dissolution-inhibiting acid gen› erators, and 

(ii) a second radiation sensitive acid generator selected from the group consisting of unprotected acidic group› functionalized radiation sensitive acid generators. 

2. The resist composition of claim 1 wherein said imaging polymer comprises a ketal-functionalized acid sensitive polymer. 

3. The resist composition of claim 1 wherein said second radiation-sensitive acid generator is an acidic group-func- 

## EXAMPLE 8 

## Optimized Formulation 

