Effect of surface treatments on interfacial adhesion energy between UV-curable resist and glass wafer

Jang, E.J.,Park, Y.B.,Lee, H.J.,Choi, D.G.,Jeong, J.H.,Lee, E.S.,Hyun, S. IPC Science and Technology Press ; Elseiver Scienc 2009 International journal of adhesion and adhesives Vol.29 No.6

The interfacial adhesion energy between the resist and the substrate is very important in nanoimprinting because of problems with the resist sticking or pulling off during separation of the mold from the substrate. Substrate surface treatments with a self-assembled monolayer or oxygen plasma provide good adhesion between a resist coating and a silica substrate. In this paper, we describe the adhesion properties of a resist and a glass wafer measured using the four-point bending test. The interfacial adhesion energy between the resist and the glass wafer was evaluated for various substrate surface treatments of adhesion promoters and anti-sticking layers. The interfacial fracture energy without treatment was 1.23J/m<SUP>2</SUP>, and was in the range 0.49-2.57J/m<SUP>2</SUP> for the other treatments tested. The interfacial fracture surfaces were also investigated by field emission scanning electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy to determine the fracture mode at the interfaces.

Characterization of the surface energies of functionalized multi-walled carbon nanotubes and their interfacial adhesion energies with various polymers

Roh, Sang Chul,Choi, Eun Yub,Choi, Yeon Sik,Kim, C.K. Elsevier 2014 Polymer Vol.55 No.6

<P><B>Abstract</B></P> <P>The surface energies of pristine multi-walled carbon nanotubes (MWCNTs) and MWCNTs functionalized with carboxylic acid (MWCNT-COOH), acyl chloride and ethyl amine were characterized, and the effects of the changes in MWCNT surface energies on the interfacial adhesion and reinforcement of the composites were explored. When the surface energy of pristine MWCNTs was compared to that of functionalized MWCNTs, a decrease in the dispersive surface energy and an increase in the polar surface energy were observed. Interfacial adhesion energies between MWCNTs and various polymers were estimated from surface energy values of MWCNTs and various polymers. Among the MWCNTs, polyethylene, polystyrene and bisphenol-A polycarbonate (PC) had the highest interfacial energy with pristine MWCNTs, while nylon 6,6 and polyacrylamine exhibited the highest interfacial energy with MWCNT-COOH. When tensile properties and adhesion at the interface of PC and nylon 6,6 composites containing MWCNTs were examined, composites having high interfacial adhesion energy exhibited greater adhesion at the interface and reinforcement.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

미세 배선 적용을 위한 Ta/Cu 적층 구조에 따른 계면접착에너지 평가 및 분석

손기락,김성태,김철,김가희,주영창,박영배,Son, Kirak,Kim, Sungtae,Kim, Cheol,Kim, Gahui,Joo, Young-Chang,Park, Young-Bae 한국마이크로전자및패키징학회 2021 마이크로전자 및 패키징학회지 Vol.28 No.1

The quantitative measurement of interfacial adhesion energy (Gc) of multilayer thin films for Cu interconnects was investigated using a double cantilever beam (DCB) and 4-point bending (4-PB) test. In the case of a sample with Ta diffusion barrier applied, all Gc values measured by the DCB and 4-PB tests were higher than 5 J/㎡, which is the minimum criterion for Cu/low-k integration without delamination. However, in the case of the Ta/Cu sample, measured Gc value of the DCB test was lower than 5 J/㎡. All Gc values measured by the 4-PB test were higher than those of the DCB test. Measured Gc values increase with increasing phase angle, that is, 4-PB test higher than DCB test due to increasing plastic energy dissipation and roughness-related shielding effects, which matches well interfacial fracture mechanics theory. As a result of the 4-PB test, Ta/Cu and Cu/Ta interfaces measured Gc values were higher than 5 J/㎡, suggesting that Ta is considered to be applicable as a diffusion barrier and a capping layer for Cu interconnects. The 4-PB test method is recommended for quantitative adhesion energy measurement of the Cu interconnect interface because the thermal stress due to the difference in coefficient of thermal expansion and the delamination due to chemical mechanical polishing have a large effect of the mixing mode including shear stress. Cu 배선(interconnect) 적용을 위한 다층박막의 적층 구조에 따른 최적 계면접착에너지(interfacial adhesion energy, Gc) 평가방법을 도출하기 위해, Ta, Cu 및 tetraethyl orthosilicate(TEOS-SiO2) 박막 계면의 정량적 계면접착에너지를 double cantilever beam(DCB) 및 4-점 굽힘(4-point bending, 4-PB) 시험법을 통해 비교 평가하였다. 평가결과, Ta확산방지층이 적용된 시편(Cu/Ta, Cu/Ta/TEOS-SiO2)에서는 두 가지 평가방법 모두 반도체 전/후 공정에서 박리가 발생하지 않는 산업체 통용 기준인 5 J/㎡ 보다 높게 측정되었다. Ta/Cu 시편의 경우 DCB 시험에서만 5 J/㎡ 보다 낮게 측정되었다. 또한, DCB시험 보다 4-PB시험으로 측정된 Gc가 더 높았다. 이는 계면파괴역학 이론에 따라 이종재료의 계면균열 선단에서 위상각의 증가로 인한 계면 거칠기 및 소성변형에 의한 에너지 손실이 증가 하는것에 기인한다. 4-PB시험결과, Ta/Cu 및 Cu/Ta계면은 5 J/㎡ 이상의 높은 계면접착에너지를 보이므로, 계면접착에너지 관점에서는 Ta는 Cu배선의 확산방지층(diffusion barrier layer) 및 피복층(capping layer)으로 적용 가능할 것으로 생각된다. 또한, 배선 집적공정 및 소자의 사용환경에서 열팽창 계수 차이에 의한 열응력 및 화학적-기계적 연마 (chemical mechanical polishing)에 의한 박리는 전단응력이 포함된 혼합모드의 영향이 크므로 4-PB 시험으로 측정된 Gc와 연관성이 더 클 것으로 판단된다.

FOWLP Cu 재배선 적용을 위한 절연층 경화 온도 및 고온/고습 처리가 Ti/PBO 계면접착에너지에 미치는 영향

손기락,김가희,박영배 한국마이크로전자및패키징학회 2023 마이크로전자 및 패키징학회지 Vol.30 No.2

The effects of dielectric curing temperature and temperature/humidity treatment conditions on the interfacial adhesion energies between Ti diffusion barrier/polybenzoxazole (PBO) dielectric layers were systematically investigated for Cu redistribution layer applications of fan-out wafer level package. The initial interfacial adhesion energies were 16.63, 25.95, 16.58 J/m2 for PBO curing temperatures at 175, 200, and 225 ℃, respectively. X-ray photoelectron spectroscopy analysis showed that there exists a good correlation between the interfacial adhesion energy and the C-O peak area fractions at PBO delaminated surfaces. And the interfacial adhesion energies of samples cured at 200 ℃ decreased to 3.99 J/m2 after 500 h at 85 ℃/85 % relative humidity, possibly due to the weak boundary layer formation inside PBO near Ti/PBO interface. 팬 아웃 웨이퍼 레벨 패키지의 Cu 재배선층 적용을 위해 Ti 확산방지층과 폴리벤즈옥사졸(polybenzoxazole, PBO) 절연층 사이의 계면 신뢰성을 평가하였다. PBO 경화 온도 및 고온/고습 시간에 따라 4점 굽힘 시험으로 정량적인 계면접착에너지를 평가하였고, 박리계면을 분석하였다. 175, 200, 및 225℃의 세 가지 PBO 경화 온도에 따른 계면접착에너지는 각각 16.63, 25.95, 16.58 J/m2 로 200℃의 경화 온도에서 가장 높은 값을 보였다. 박리표면에 대한 X-선 광전자 분광분석 결과, 200℃에서 PBO 표면의 C-O 결합의 분율이 가장 높으므로, M-O-C 결합이 Ti/PBO 계면접착 기구와 연관성이높은 것으로 판단된다. 200℃에서 경화된 시편을 85℃/85% 상대 습도에서 500시간 동안 고온/고습 처리 하는 동안 계면접착에너지는 3 .99 J/m2까지 크게 감소하였다. 이는 고온/고습 처리동안 Ti/PBO 계면으로의 지속적인 수분 침투로 인해 계면 근처 PBO의 화학결합이 약해져서 weak boundary layer를 형성하기 때문으로 판단된다.

FOWLP 적용을 위한 Cu 재배선과 WPR 절연층 계면의 정량적 계면접착에너지 측정방법 비교 평가

김가희,이진아,박세훈,강수민,김택수,박영배 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.2

Fan-out wafer level packaging (FOWLP) 적용을 위한 최적의 Cu 재배선 계면접착에너지 측정방법을 도출하기 위해, 전기도금 Cu 박막과 WPR 절연층 계면의 정량적 계면접착에너지를 90o 필 테스트, 4점 굽힘 시험법, double cantilever beam (DCB) 측정법을 통해 비교 평가 하였다. 측정 결과, 세 가지 측정법 모두 배선 및 패키징 공정 후 박리가 일어나지 않는 산업체 통용 기준인 5 J/m2보다 높게 측정되었다. 또한, DCB, 4점 굽힘 시험법, 90o 필 테스트 순으로계면접착에너지가 증가하는 거동을 보였는데, 이는 계면파괴역학 이론에 의해 위상각 증가에 따라 이종재료 계면균열 선단의 전단응력성분 증가에 따른 소성변형에너지 및 계면 거칠기 증가 효과에 의한 것으로 설명이 가능하다. FOWLP 재배선에 대한 최적의 계면접착에너지 도출을 위해서는 시편제작 공정, 위상각 차이, 정량적 측정 정확도 및 결합력 크기등을 고려하여 4점 굽힘 시험법 또는 DCB 측정법을 적절히 혼용 사용하는 것이 타당한 것으로 판단된다. The quantitative interfacial adhesion energy measurement method of copper redistribution layer and WPR dielectric interface were investigated using 90o peel test, 4-point bending test, double cantilever beam (DCB) measurement for FOWLP Applications. Measured interfacial adhesion energy values of all three methods were higher than 5 J/m2, which is considered as a minimum criterion for reliable Cu/low-k integration with CMP processes without delamination. Measured energy values increase with increasing phase angle, that is, in order of DCB, 4-point bending test, and 90o peel test due to increasing roughness-related shielding and plastic energy dissipation effects, which match well interfacial fracture mechanics theory. Considering adhesion specimen preparation process, phase angle, measurement accuracy and bonding energy levels, both DCB and 4-point bending test methods are recommended for quantitative adhesion energy measurement of RDL interface depending on the real application situations.

후속 열처리에 따른 Cu 박막과 ALD Ru 확산방지층의 계면접착에너지 평가

정민수,이현철,배병현,손기락,김가희,이승준,김수현,박영배 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.3

The effects of Ru deposition temperature and post-annealing conditions on the interfacial adhesion energies of atomic layer deposited (ALD) Ru diffusion barrier layer and Cu thin films for the advanced Cu interconnects applications were systematically investigated. The initial interfacial adhesion energies were 8.55, 9.37, 8.96 J/m2 for the sample deposited at 225, 270, and 310oC, respectively, which are closely related to the similar microstructures and resistivities of Ru films for ALD Ru deposition temperature variations. And the interfacial adhesion energies showed the relatively stable high values over 7.59 J/m2 until 250h during post-annealing at 200oC, while dramatically decreased to 1.40 J/m2 after 500 h. The X-ray photoelectron spectroscopy Cu 2p peak separation analysis showed that there exists good correlation between the interfacial adhesion energy and the interfacial CuO formation. Therefore, ALD Ru seems to be a promising diffusion barrier candidate with reliable interfacial reliability for advanced Cu interconnects. 차세대 초미세 Cu 배선 적용을 위한 원자층증착법(atomic layer deposition, ALD)을 이용하여 증착된 Ru확산방지층과 Cu 박막 사이의 계면 신뢰성을 평가하기 위해, Ru 공정온도 및 200oC 후속 열처리 시간에 따라 4점굽힘시험으로 정량적인 계면접착에너지를 평가하였고, 박리계면을 분석하였다. 225, 270, 310oC 세 가지 ALD Ru 공정온도에 따른계면접착에너지는 각각 8.55, 9.37, 8.96 J/m2로 유사한 값을 보였는데, 이는 증착온도 변화에 따라 Ru 결정립 크기 등 미세조직 및 비저항의 차이가 적어서, 계면 특성도 거의 차이가 없는 것으로 판단된다. 225oC의 공정온도에서 증착된 Ru 박막의 계면접착에너지는 200oC 후속 열처리시 250시간까지는 7.59 J/m2 이상으로 유지되었으나, 500시간 후에는 1.40 J/ m2로 급격히 감소하였다. 박리계면에 대한 X-선 광전자 분광기 분석 결과, 500시간 후 Cu 계면 산화로 인하여 계면접착에너지가 감소한 것으로 확인되었다. 따라서 ALD Ru 박막은 계면신뢰성이 양호한 차세대 Cu 배선용 확산방지층 후보가 된다고 판단된다.

Effects of Post-annealing and Co Interlayer Between SiNx and Cu on the Interfacial Adhesion Energy for Advanced Cu Interconnections

Hyeonchul Lee,Minsu Jeong,김가희,Kirak Son,Jeongmin Seo,Taek-Soo Kim,Young-Bae Park 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.4

Effects of Co interlayer and 200 °C post-annealing treatment on interfacial adhesion energy of SiNx/Cu structure were systematically investigated. Initial interfacial adhesion energy of SiNx/Cu structure measured by double cantilever beam test was 0.92 J/m2. The interfacial adhesion energy increased to 2.94 J/m2 with Co interlayer between SiNx and Cu films. After post-annealing treatment at 200 °C for 500 h, the interfacial adhesion energy of SiNx/Co/Cu structure decreased to 0.95 J/m2. X-ray photoelectron spectroscopy analysis revealed that the interfacial adhesion energy increased for SiNx/Co/Cu thin films due to CoSi2 reaction layer at SiNx/Co interface, but sharply decreased during post-annealing treatment by SiO2 formation at SiNx/Co interface.

후속열처리 및 고온고습 조건에 따른 Cu 배선 확산 방지층 적용을 위한 ALD RuAlO 박막의 계면접착에너지에 관한 연구

이현철,정민수,배병현,천태훈,김수현,박영배,Lee, Hyeonchul,Jeong, Minsu,Bae, Byung-Hyun,Cheon, Taehun,Kim, Soo-Hyun,Park, Young-Bae 한국마이크로전자및패키징학회 2016 마이크로전자 및 패키징학회지 Vol.23 No.2

The effects of post-annealing and temperature/humidity conditions on the interfacial adhesion energies of atomic layer deposited RuAlO diffusion barrier layer for Cu interconnects were systematically investigated. The initial interfacial adhesion energy measured by four-point bending test was $7.60J/m^2$. The interfacial adhesion energy decreased to $5.65J/m^2$ after 500 hrs at $85^{\circ}C$/85% T/H condition, while it increased to $24.05J/m^2$ after annealing at $200^{\circ}C$ for 500 hrs. The X-ray photoemission spectroscopy (XPS) analysis showed that delaminated interface was RuAlO/$SiO_2$ for as-bonded and T/H conditions, while it was Cu/RuAlO for post-annealing condition. XPS O1s peak separation results revealed that the effective generation of strong Al-O-Si bonds between $AlO_x$ and $SiO_2$ interface at optimum post-annealing conditions is responsible for enhanced interfacial adhesion energies between RuAlO/$SiO_2$ interface, which would lead to good electrical and mechanical reliabilities of atomic layer deposited RuAlO diffusion barrier for advanced Cu interconnects. 차세대 반도체의 초미세 Cu 배선 확산방지층 적용을 위해 원자층증착법(atomic layer deposition, ALD) 공정을 이용하여 증착한 RuAlO 확산방지층과 Cu 박막 계면의 계면접착에너지를 정량적으로 측정하였고, 환경 신뢰성 평가를 수행하였다. 접합 직후 4점굽힘시험으로 평가된 계면접착에너지는 약 $7.60J/m^2$으로 측정되었다. $85^{\circ}C$/85% 상대습도의 고온고습조건에서 500시간이 지난 후 측정된 계면접착에너지는 $5.65J/m^2$로 감소하였으나, $200^{\circ}C$에서 500시간 동안 후속 열처리한 후에는 $24.05J/m^2$으로 계면접착에너지가 크게 증가한 것으로 평가되었다. 4점굽힘시험 후 박리된 계면은 접합 직후와 고온고습조건의 시편의 경우 RuAlO/$SiO_2$ 계면이었고, 500시간 후속 열처리 조건에서는 Cu/RuAlO 계면인 것으로 확인되었다. X-선 광전자 분광법 분석 결과, 고온고습조건에서는 흡습으로 인하여 강한 Al-O-Si 계면 결합이 부분적으로 분리되어 계면접착에너지가 약간 낮아진 반면, 적절한 후속 열처리 조건에서는 효과적인 산소의 계면 유입으로 인하여 강한 Al-O-Si 결합이 크게 증가하여 계면접착에너지도 크게 증가한 것으로 판단된다. 따라서, ALD Ru 확산방지층에 비해 ALD RuAlO 확산방지층은 동시에 Cu 씨앗층 역할을 하면서도 전기적 및 기계적 신뢰성이 우수할 것으로 판단된다.

Cooptimization of Adhesion and Power Conversion Efficiency of Organic Solar Cells by Controlling Surface Energy of Buffer Layers

Lee, Inhwa,Noh, Jonghyeon,Lee, Jung-Yong,Kim, Taek-Soo American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.42

<P>Here, we demonstrate the cooptimization of the interfacial fracture energy and power conversion efficiency (PCE) of poly[N-9'-heptadecany1-2,7-carbazole-alt-5,5-(4',7'di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT)-based organic solar cells (OSCs) by surface treatments of the buffer layer. The investigated surface treatments of the buffer layer simultaneously changed the crack path and interfacial fracture energy of OSCs under mechanical stress and the work function of the buffer layer. To investigate the effects of surface treatments, the work of adhesion values were calculated and matched with the experimental results based on the Owens-Wendt model. Subsequently, we fabricated OSCs on surface treated buffer layers. In particular, ZnO layers treated with poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7(9,9-dioctylfluorene)] (PFN) simultaneously satisfied the high mechanical reliability and PCE of OSCs by achieving high work of adhesion and optimized work function.</P>

3차원 적층패키지의 Cu-Cu 접합부의 정량적 접합강도 평가 및 향상에 관한 연구

장은정,김재원,Kim, Bioh,Thorsten Matthias,현승민,이학주,박영배 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

The quantitative interfacial adhesion energy of Cu-Cu direct thermo-compression specimen with bonding temperature and wet pre-treatment was measured by using 4 point bending test for 3-D IC integration. The evaluated interfacial adhesion energy was 2.79±0.82, 3.46±0.87, 4.93±0.2 J/㎡ bonding temperature 300, 350, 400℃ and 0.29, 1.28, 1.64, 1.17 and 0.43 J/㎡ acetic acid pre-treatment at 35℃ for 0, 1, 5, 10, and 15 min. From the result, 5 min treated Cu to Cu thermo-compression bonding has the highest interfacial adhesion energy at 350℃.