Electron-Beam-Induced Decomposition Mechanisms of High-Sensitivity Chlorinated Resist ZEP520A

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ZEP resist patterns, which have been widely used in nanofabrication in research laboratories, are shrunk during an SEM observation. This shrinkage effect makes it challenging to accurately determine their original sizes. In this work, the shrinkage effect of electron beams on ZEP resist line-space patterns was explored by AFM measurement at different exposure doses. The results shown that the shrinkage happened at doses as low as 0.05 mC/cm 2 , and dramatically increased before being saturated at high doses of 16 -24 mC/cm 2 (at 30 keV). For patterns with the same height, a smaller pattern tended to undergo a bigger shrinkage. The heights of patterns also had a great impact on their shrinkages. In the saturation region at high does, the patterns were unchanged in isopropyl alcohol developer. The insolubility of the patterns suggested that the resist had changed to a negative tone, where the number of crosslinking sites of the resist was high, and caused the saturation of shrinkage. A new method for estimating of the original size was also introduced using a combination of SEM, EB exposure, and AFM.

Section: 5mentioning

confidence: 89%

Section: 5mentioning

confidence: 92%

Section: Shrinkage Of 154nm-height Patterns With Different Linewidthsmentioning

confidence: 96%

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Electron-Beam Induced Shrinkage Effects on Line-Space Patterns of ZEP Resist

Dinh

Oshima

Nishijima

et al. 2016

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“…In previous work, the mechanisms of degradation of ZEP520A were investigated based on analysis of the final products of degradation by means of X-ray photoelectron spectroscopy (XPS), gel permeation chromatography (GPC), Fourier transform IR spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) spectroscopy. Efficient random chain scission with a G-value of approximately 8 was observed by means of GPC [7], and the decomposition of C−Cl bonds in irradiated ZEP520A was observed using XPS and FT-IR [6,7]. Moreover, NMR spectroscopy confirmed that terminal double bonds (−CH=CH 2 ) generated via main-chain scission were formed at both the α-chloromethacrylate unit and α-methylstyrene unit [7].…”

Section: Introductionmentioning

confidence: 92%

Pulse Radiolysis Study on a Highly Sensitive Chlorinated Resist ZEP520A

Hosaka

Oyama

Oshima

et al. 2013

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ZEP520A is one of the most popular positive electron beam (EB) resists used in research and photomask fabrication owing to its good spatial resolution, high sensitivity, and high dry etching resistance. Herein, EB-induced early reactions of ZEP520A were investigated via pulse radiolysis. Dissociative electron attachment and formation of a charge transfer complex were definitive contributing factors to the efficient degradation of ZEP520A. Furthermore, products induced by direct ionization of ZEP520A were observed in a highly concentrated ZEP520A solution in tetrahydrofuran, suggesting that early reactions in the ZEP520A solid film that were induced only by direct ionization could be simulated during pulse radiolysis in specific solutions.

“…It is known that its halogen groups are easier to react to the electron or EUV light, so it is cut inside molecular and promoted to dissociate combinations. In addition, gL3002-T has simple chemical structure which is same formula of ZEP520-A [4] as shown in Fig. 1.…”

Section: Experiments Samplementioning

confidence: 99%

Resist Investigation Method using <i>ab initio</i> MO Calculation on basis of Approximation Molecular Model

Nagata

Niihara

Harada

et al. 2017

The technical issues of EUV resist are high resolution, high sensitivity, low line edge roughness (LER), and low outgas. Between these, there is a trade-off relationship, and the most significant point in these issues is the simultaneous achievement of high sensitivity and low LER. In order to efficiently develop high-performance EUV resist, it is necessary to understand the chemical reaction of EUV resist. Thus, we have studied the EUV chemical reaction using the soft X-ray absorption spectroscopy. In this method, the absorption spectra had a lot of absorption peak which could not be assigned to the chemical bonding. For analysis of these unknown peaks, the molecular orbital (MO) calculation using the first principle, socalled "ab initio", is expected to be an effective support computation method. Since the chemicalstructural-optimization is necessary for the first-principle calculation, we introduced the MO calculation software Conflex that can search the position of reactive active molecules in the conformational space, optimize resist chemical structure, and create a resist molecular model. Based on this optimized molecular model, the MO calculation software Gaussian was performed to calculate IR spectrum. By comparing the IR spectra obtained by an experiment and the calculation, some IR peaks was assigned to a chemical group, and chemical-bond transformation was suggested. From these results, it was confirmed that MO calculation had an ability for analyze the chemical reaction of resist material. Thus, MO calculation can accelerate the development of high-performance resist material, which will help a breakthrough of semiconductor devices for "the internet of things".