광산발생제가 결합된 고분자 레지스트의 합성과 전자빔 리소그래피용 레지스트 특성 향상

Abstract

Next generation lithography is required to achieve critical lithographic performances. Electron beam lithography (EBL) is one of candidates for reaching below 10 nm resolution for device fabrication. Photoresist has an important role in the lithographic performance, and photoacid generator (PAG) is a key component in photoresist for high-resolution patterning with high sensitivity. A triphenylsulfonium salt methyl methacrylate (TPSMA), which includes triphenylsulfonium triflate as a PAG, was synthesized and polymerized with various monomers for polymer-bound PAG. Characterization of polymers-bound PAG was carried out by NMR and FTIR. The molecular weight was analyzed by GPC. Thermal properties were studied using TGA and DSC. The characterization results were in good agreement with corresponding chemical compositions and thermal stability. Polymers-bound PAG were subsequently employed in electron beam lithography and its lithographic performance was confirmed by FE-SEM. These polymers-bound PAG were accomplished to improve the lithographic performance including sensitivity, line width roughness (LWR) and resolution. We found that polymer-bound PAG was capable of 20 nm negative tone patterns with better sensitivity than hydrogensilsesquioxane (HSQ) which is a conventional negative tone resist. Additionally, the out-gassing characteristic of polymer-bound PAG also was examined to be used as extreme ultraviolet (EUV) resist by using EUVL Test Bed Beam Line 11B of Pohang Accelerator Laboratory. |반도체 산업의 발전으로 인해 고 집적화된 소자와 디바이스 제작을 위해 고해상도, 좋은 감도, line width roughness 의 패턴 제작이 요구되고 있으며 그에 따라 차세대 리소그래피 기술의 개발이 진행 되고 있다. 전자빔 리소그래피는 10 nm이하의 디바이스 제작을 위한 차세대 리소그래피 기술의 하나로 알려져 있으며 그에 따라 전자빔 리소그래피용 레지스트의 개발을 진행 하였다. 포토레지스트는 리소그래피 공정 중에 사용되는 핵심 재료로 나노사이즈의 패턴 제작을 위해 성능 향상이 요구 되고 있다. 좋은 감도의 고해상도 패턴 제작을 위해 광산발생제 (PAG)는 레지스트의 핵심적인 요소로 고분자 레진과 blend하여 사용되어 왔다. 본 연구에선 PAG 을 직접 고분자 레진에 결합시키기 위해 광산발생제인 triphenylsulfonium triflate 을 포함하는 triphenylsulfonium salt methyl methacrylate (TPSMA) 를 합성하였고 TPSMA 를 다양한 단량체와 중합하여 polymers-bound PAG 을 제작하였다. 중합된 polymers-bound PAG 의 구조적 특성은 NMR 과 FTIR 을 이용하여 확인하였고 분자량은 GPC를 이용하여 측정하였다. TGA 와 DSC를 통해 레지스트의 열적 특성을 확인하였으며 좋은 안정성을 확인하였다. Polymers-bound PAG 를 이용해 전자빔 리소그래피를 수행한 결과, negative tone 의 패턴이 형성 되었고 고해상도와 좋은 line width roughness (LWR) 의 향상된 패턴을 얻었다. 패턴은 FE-SEM 을 이용하여 확인하였다. 우리의 polymer-bound PAG 은 20 nm 이하의 negative tone 의 패턴 제작에 상업적으로 이용되고 있는 hydrogensilsesquioxane (HSQ) 보다 좋은 감도를 보였으며 포항 가속기 연구소의 EUVL Test Bed Beam Line 11B 를 이용하여 out-gassing 특성을 확인 하여 extreme ultraviolet (EUV) 리소그래피의 레지스트로 응용 가능성을 확인하였다.; Next generation lithography is required to achieve critical lithographic performances. Electron beam lithography (EBL) is one of candidates for reaching below 10 nm resolution for device fabrication. Photoresist has an important role in the lithographic performance, and photoacid generator (PAG) is a key component in photoresist for high-resolution patterning with high sensitivity. A triphenylsulfonium salt methyl methacrylate (TPSMA), which includes triphenylsulfonium triflate as a PAG, was synthesized and polymerized with various monomers for polymer-bound PAG. Characterization of polymers-bound PAG was carried out by NMR and FTIR. The molecular weight was analyzed by GPC. Thermal properties were studied using TGA and DSC. The characterization results were in good agreement with corresponding chemical compositions and thermal stability. Polymers-bound PAG were subsequently employed in electron beam lithography and its lithographic performance was confirmed by FE-SEM. These polymers-bound PAG were accomplished to improve the lithographic performance including sensitivity, line width roughness (LWR) and resolution. We found that polymer-bound PAG was capable of 20 nm negative tone patterns with better sensitivity than hydrogensilsesquioxane (HSQ) which is a conventional negative tone resist. Additionally, the out-gassing characteristic of polymer-bound PAG also was examined to be used as extreme ultraviolet (EUV) resist by using EUVL Test Bed Beam Line 11B of Pohang Accelerator Laboratory.