Useful protocol for evaluating subtle and important differences between photoresist formulations

Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures

Volumn 22, Issue 3, 2004, Pages 869-874

  Pawloski, Adam R ^a   Nealey, Paul F ^b  

^a ADVANCED MICRO DEVICES   (United States)

^b University of Wisconsin Madison   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

FOURIER TRANSFORM INFRARED SPECTROSCOPY; INFRARED SPECTROSCOPY; NANOTECHNOLOGY; PHOTOLITHOGRAPHY; POLYMERS; SILICON WAFERS; STOICHIOMETRY; STRUCTURE (COMPOSITION);

INFRARED REFLECTANCE; PHOTOACIDS; POLYMER FILMS;

PHOTORESISTS;

EID: 3242705165     PISSN: 10711023     EISSN: None     Source Type: Journal    
DOI: 10.1116/1.1695337     Document Type: Article

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15. 2/mJ. The results from the present study determined a greater C parameter than earlier work for the ND-Tf/PTBOCST system. There were several key differences in these experiments that likely explain the discrepancy between measurements. In the prior work, the concentration of ND-Tf was 80 μmol/g in the resist, the postapplication bake was at 90 °C for 60 s, the initial film thickness was approximately 800 nm, and the postexposure bake occurred at 90 °C for 90 s. It is important to recognize that the resist C parameter is a measurement of the overall efficiency of the photoacid generation process in the resist film, and is not a true measurement of the quantum yield of the PAG. It is entirely possible that factors in addition to the radiation chemistry during exposure may affect the magnitude of the C parameter. For example, in Ref. 11 we demonstrated that the concentration of PAG in the resist impacts the apparent efficiency of the photoacid generation process, with greater concentrations of PAG resulting in less efficient photoacid generation.
16. One caveat to the standard addition technique is that the determination of photoacid concentrations is made indirectly from the neutralization of photoacid by base. The major assumption of the technique is that the base acts only to neutralize a stoichiometric equivalence of photogenerated acid prior to the postexposure bake. The verification of this assumption for the 1PE base quencher in PTBOCST can be found in Refs. 4 and 5
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