Paper
1 July 1991 Simulation analysis of deep-UV chemically amplified resist
Takeshi Ohfuji, Masanobu Soenosawa, Hiroshi Nozue, Kunihiko Kasama
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Abstract
The simulation analysis of standing wave effects in deep-UV lithography, which is the most serious problem in 64 MDRAM fabrication, is studied. One lithographic problem for device fabrication is periodic linewidth variation due to multireflection light in the resist film. It was observed that the amplitude of linewidth variation was more than 0.1 micrometers for a 3- component chemically amplified negative resist using a KrF excimer laser stepper (NAequals0.42). So, we simulated the standing wave effect as a function of resist material, exposure tool, and process conditions in order to minimize periodic linewidth variation. The SAMPLE simulator was improved to calculate a series of pattern profiles automatically, to change simulation parameters, and to create a periodic linewidth curve from the simulated pattern profiles. The following discoveries were made: Increasing optical resistance slightly decreases linewidth variation, although the resist pattern profiles degrade significantly. High NA lenses can also decrease linewidth variation under best focus conditions, but, linewidth variation increases significantly under slight defocus. Also, an optimum lens NA value, that minimizes periodic linewidth error, was found. Finally the Anti-Reflecting-Coating (ARC) technique, which can diminish standing wave effects, also degrades pattern profiles. To summarize, in order to minimize linewidth variation due to standing wave effects, it is important to minimize reflectivity, to optimize lens NA and coherency factor by simulation analysis.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Takeshi Ohfuji, Masanobu Soenosawa, Hiroshi Nozue, and Kunihiko Kasama "Simulation analysis of deep-UV chemically amplified resist", Proc. SPIE 1463, Optical/Laser Microlithography IV, (1 July 1991); https://doi.org/10.1117/12.44794
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KEYWORDS
Reflectivity

Lithography

Chemical analysis

Absorbance

Chemically amplified resists

Deep ultraviolet

Photoresist processing

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