Analysis of the Photoresist and Its Possible By-product Used in Semiconductor Manufacturing Industries

Abstract

Objective: The semiconductor industry is known to use various chemicals but little is known. Especially, numerous chemical compounds including organic solvents and trade secrets have been used in photolithography process. The purpose of this study was to identify the chemical constituents of photoresist products and their by-products, and to compare the constituents with material safety data sheets (MSDS) and analytical results. Methods: A total of 51 photoresists with 48 MSDS were collected from 4 companies. Analysis consisted of two parts

first, the constituents of the chemical products were identified with MSDS and organic solvents were analyzed by the gas chromatography with mass spectrometer (GC/MS) for qualitative evaluation and gas chromatography with flame ionization detector (GC/FID) for quantitative analysis. Second

for verification of by-product of the chemical products, analysis was performed by headspace solid-phase microextraction (HP-SPME) with GC/MS. The 75 ㎛ carboxen /polydimethylsiloxane (CAR/PDMS) fiber for VOCs and the 65 ㎛ polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber for formaldehyde were used. The chemical constituents were categorized according to its hazard indices carcinogen, mutagen, reproductive toxicant, and trade secret. Results: Forty-five out of 48 (94%) products contained trade secrets, and its amount range was from 1 to 65%. A total of 238 ingredients with multiple counting (35 ingredients removing multiple counting) were identified in MSDS of 48 products and 48.7% of ingredients were labeled as a trade secret. In the result of analysis, 5 ingredients which should not be designated as a trade secret by Korea Occupational Safety Health Act (KOSHAct) were detected and not specified their toxicological information in MSDS, and the concordance rates between MSDS and analytical result was 41.7%. In the result of the analysis of by-products, 129 chemicals classified according to CAS No. were detected, and 17 chemicals were CMRs. Also formaldehyde was released from 12 of 21 products which use novolak resin. Conclusion: We confirmed that several photoresists contain carcinogens, and some were not specified their toxicological information in MSDS. Also, hazardous chemicals including benzene and formaldehyde were released from photoresist products as the by-products. Therefore, it is necessary to establish a systematic management system of chemical compounds and the working environment.