수소 열처리에 따른 구리 박막의 응집 거동 현상

베준우,임재원,Minoru Isshiki 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.9

The agglomeration and time dependence of Cu films in Cu(100 nm)/Ta(50 nm)/Si structure deposited by ion beam deposition was examined. Copper thin films were annealed at 650℃ for 1 to 60 min in hydrogen atmosphere. The surface morphology, crystalline microstructure and electrical resistivity were investigated by field-emission scanning electron microscopy, X-ray diffraction and Van der Pauw method, respectively. Experimental results revealed that the nucleation and growth of voids ocurred in the copper film annealed for 5 min. Further annealing made the film a connected island structure and then isolated island structure.

Precise Analysis of H, C, N, and O as Dominant Impurities in Cu Films: Complementary Use of SIMS and GDMS

Jae Won Lim 대한금속학회 2005 METALS AND MATERIALS International Vol.11 No.4

비질량분리형 이온빔증착법에 의한 ULSI 금속배선용 구리박막에 관한 특성연구

임재원,Isshiki, Minoru 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.8

Cu thin films have been deposited on Si (100) substrate by using a non-mass separated ion beam deposition system. The effect of the substrate bias voltage on the properties of the deposited films was investigated using X-ray diffraction, resistivity measurement and scanning electron microscopy. In the case of Cu thin films deposited without bias voltage, a columnar structure and small grains were observed distinctly, and the electrical resistivity of the deposited Cu films was very high. By applying the substrate bias voltage, no clear columnar structure and grain boundary were observed. The resistivity of Cu films decreased remarkably and reached a minimum value of 1.8±0.1μΩcm at a bias voltage of -50V, which is close to that of Cu bulk (1.67 μΩcm).

음의 기판 바이어스에 의한 탄탈 박막내의 주요불순물의 농도감소

임재원,Isshiki, Minoru 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.4

Ta films were deposited on Si (100) substrates at substrate bias voltages of 0 V, -50 V, and -125 V by a non-mass separated ion beam deposition. Secondary ion mass spectrometry (SIMS) and glow discharge mass spectrometry (GDMS) were used to determine the concentrations of dominant impurity elements, i.e., H, C, N, and 0, which are likely to contaminate Ta films during the deposition. The GDMS results revealed that dominant impurities during the deposition were C, N, and 0 elements and many unknown peaks observed in the SIMS spectra of the Ta film were assigned to cluster states such as C_(x)H_(x), O_(x)H_(x), C_(x)O_(x)H_(x). Furthermore, it was found that the concentrations of these impurities in the Ta films can be controlled by the negative substrate bias voltage. (Received September 7, 2005)

SIMS와 GDMS를 이용한 구리와 탄탈 박막내의 주요불순물 분석

임재원,Minoru Isshiki 한국진공학회 2004 Applied Science and Convergence Technology Vol.13 No.2

본 논문은 구리와 탄탈 박막내에 불순물로써 함유되기 쉬운 수소와 탄소, 그리고 산소 원소에 대해 이차이온 질량분석기(secondary ion mass spectrometry)와 글로우방전 질량분석기(glow discharge mass spectrometry)를 이용하여 분석하였고, 이들의 분석결과에 대해서 고찰하였다. 구리와 탄탈 박막은 실리콘 기판 위에 비질량 분리형 이온빔 증착장비를 이용하여 기판 바이어스를 걸지 않은 경우와 -50 V(구리 박막) 또는 -125 V(탄탈 박막)의 기판바이어스를 걸은 상태에서 증착하였다. 세슘 이온빔을 이용하여 분석한 SIMS 결과에서, 기판 바이어스를 걸지 않은 경우, 상당히 많은 피크들이 강하게 관찰되었는데 이는 위의 주요불순물들의 결합에 의한 상태로 검출된 것으로 이들 주요불순물들의 조합에 의해 가능한 질량번호를 산출하여 SIMS 결과의 모든 피크들을 해석할 수 있었다. 또한, 박막 내의 주요불순물들의 정량적인 GDMS 분석에 의해 SIMS 결과와의 일치성을 확인할 수 있었다. Secondary ion mass spectrometry(SIMS) and glow discharge mass spectrometry(GDMS) were used to determine the impurity concentrations of hydrogen, carbon, and oxygen elements in the Cu and Ta films, and the results of SIMS and GDMS analysis were carefully considered. The Cu and Ta films were deposited on Si (100) substrates at zero substrate bias voltage and a substrate bias voltage of -50 V(Cu films) or -125 V(Ta films) using a non-mass separated ion beam deposition method. As a result of SIMS with Cs+ ion beam, in the case of the Cu and Ta films deposited without the substrate bias voltage, many strong peaks were observed, which is considered to be detected as a the cluster state such as CxHx, OxHx, CxOxHx. All the peaks of SIMS results could be interpreted by the combination of these dominant impurities. Moreover, it was confirmed that the quantitative results of GDMS analysis were accordant to the SIMS results.

고주파 스퍼터타입 이온소스를 이용한 비질량분리형 이온빔증착법에 관한 특성연구

임재원,Minoru Isshiki 한국진공학회 2003 Applied Science and Convergence Technology Vol.12 No.2

본 논문은 비질량분리형 이온빔증착법에 이용하기 위한 고순도의 고주파 스퍼터타입 이온소스에 대한 특성을 평가했다. 고주파 구리 코일과 고순도 (99.9999 %)의 구리 타겟으로 이루어진 이온소스에 대한 기본적인 특성과 ULSI금속배선용 구리 박막으로의 응용가능성에 대해서 고찰하였다. 구리 타겟에 걸어주는 전압에 따른 구리 타겟에 흐르는 전류 특성을 고주파 전원 또는 아르곤 가스 압력을 변화시키면서 특성을 평가한 후 구리박막제작을 위한 조건에 대해서 고찰하였다. 박막 증착을 위한 기본적인 조건으로써, 타겟의 전압 -300 V와 고주파 전원 240 W, 그리고 아르곤 압력 9 Pa이 정해졌으며, 이 같은 조건에서 기판 바이어스 -50 V에서 증착된 구리 박막의 비저항값은 1.8 $\pm$ 0.1 $mu\Omega$cm로 이는 구리 벌크의 저항값(1.67 $\pm$ 0.1 $\mu\Omega$cm)에 근접한 값임을 알 수 있었다. In this paper, high purity RF sputter-type ion source for non-mass separated ion beam deposition was evaluated. The fundamental characteristics of the ion source which is composed of an RF Cu coil and a high purity Cu target (99.9999 %) was studied, and the practical application of Cu thin films for ULSI metallization was discussed. The relationship between the DC target current and the DC target voltage at various RF power and Ar gas pressures was measured, and then preparation conditions for Cu thin films was described. As a result, it was found that the deposition conditions of the target voltage, the target current and the Ar pressure were optimized at -300 V, 240 W and 9 Pa, respectively. The resistivity of Cu films deposited at a bias voltage of -50 V showed a minimum value of 1.8 $\pm$ 0.1 $mu\Omega$cm, which is close to that of Cu bulk (1.67 $mu\Omega$cm).

기판 바이어스에 의한 구리 seed layer의 특성 향상

임재원,Isshiki, Minoru 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.2

Cu films as a seed layer were deposited on Si (100) substrates by applying a negative substrate bias voltage. The electrical resistivity, surface roughness, impurity content and step coverage of the Cu films were investigated using the resistivity measurement, X-ray diffraction analysis, atomic force microscopy, secondary ion mass spectroscopy and scanning electron microscopy. The Cu films deposited at the substrate bias voltage of -50 V showed higher purity, stronger (111) preferred orientation, smoother surface and better step coverage than those of the Cu films deposited without the substrate bias voltage. The electrical resistivity of the Cu films considerably increased as the film thickness decreased. In the case of Cu(100nm)/Ta(50nm)/Si structures, the Cu films deposited by applying the substrate bias voltage maintained a complete (111) preferred orientation without (200) texture even after the thermal annealing at 450℃ for 60 min.

Ta 확산 방지막 특성에 미치는 기판 바이어스에 관한 연구

임재원,배준우,Minoru Isshiki 한국진공학회 2003 Applied Science and Convergence Technology Vol.12 No.3

본 논문은 탄탈 확산 방지막의 증착시 음의 기판 바이어스에 의한 탄탈막의 특성변화와 열적 안정성에 대해서 고찰하였다. 기판 바이어스를 걸지 않은 경우, 탄탈막은 원주형 모양의 결정 성장을 보이는 주상구조와 250 $\mu\Omega$cm의 높은 비저항값을 보였으나, 기판 바이어스를 걸어줌에 파라서 주상구조가 아닌 치밀한 미세구조와 표면이 평탄한 막이 형성되었고 비저항값도 현저히 감소되었으며, 특히 -125 V에서 증착된 탄탈막은 비저항값이 약 40 $\mu\Omega$cm로 이는 탄탈 벌크의 저항값 (13 $\mu\Omega$cm)에 근접한 값임을 알 수 있었다. 또한, 탄탈 확산 방지막의 열적 안정성에 대해서도, 기판 바이어스를 걸지 않은 탄탈막의 경우 $400^{\circ}C$에서 구리와 실리콘의 반응에 의해 비저항 값이 크게 증가한 결과에 비해, 기판 바이어스에 의해 증착된 탄탈막의 경우 $600^{\circ}C$까지 확산 방지막의 효과를 유지하고 있는 것으로 관찰되었다. Ta diffusion barriers have been deposited on Si (100) substrate by applying a negative substrate bias voltage. The effect of the substrate bias voltage on the properties of the Ta films was investigated. In the case of the Ta films deposited without the substrate bias voltage, a columnar structure and small grains were observed distinctly, and the electrical resistivity of the deposited Ta films was very high (250 $\mu\Omega$cm). By applying the substrate bias voltage, no clear columnar structure and grain boundary were observed. The resistivity of the Ta films decreased remarkably and at a bias voltage of -125 V, reaching a minimum value of 40 $\mu\Omega$cm, which is close to that of Ta bulk (13 $\mu\Omega$cm). The thermal stability of Cu(100 mm)/Ta(50 mm)/Si structures was evaluated after annealing in H2 atmosphere for 60 min at various temperatures. The Ta films deposited by applying the substrate bias voltage were found to be stable up to $600^{\circ}C$, while the Ta films deposited without the substrate bias voltage degraded at $400^{\circ}C$.

기판 바이어스에 의해 증착된 Ta 확산 방지막의 열적 안정성

임재원,배준우,Isshiki, Minoru 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.11

The interfacial reactions of the Cu(100 nm)/Ta(50 nm)/Si structures and their relationship with the microstructure of Ta diffusion barriers are investigated. The Ta films were deposited on Si (100) substrates at various bias voltages ranging from 0 to -200 V. The Ta diffusion barrier which was deposited at the substrate bias voltages of -50 V and -125 V prevented Cu-Si interaction up to 600℃ in flowing purified H₂ for 60 min, whereas the Ta layer with a columnar structure which was deposited at zero bias voltage degraded at 400℃. It was found that a slight resistivity increase of the Cu/Ta(-50 V or -125 V)/Si structures at 650℃ seemed to be due to a Cu agglomeration. To confirm the thermal stability of the Ta diffusion barrier deposited at the substrate bias voltage, a SiO₂ capping layer was used as a suppressor and was deposited on the Cu/Ta(-125 V)/Si structure. As a result, the Cu/Ta(-125 V)/Si structures were stable up to 650℃ without the Cu-Si interaction. Two different reactions of the Cu/Ta(0 V)/Si and the Cu/Ta(-50 V or -125 V)/Si structures concerning the thermal stability were discussed on the basis of the experimental results.

이차이온 질량분석기를 이용한 탄탈 박막내의 불순물 분석

임재원,배준우,Minoru Isshiki 한국진공학회 2004 Applied Science and Convergence Technology Vol.13 No.1

본 논문은 탄탈 박막의 증착시 음의 기판 바이어스에 의한 탄탈 박막내의 불순물 농도변화에 대해서 고찰하였다. 탄탈 박막은 실리콘 기판 위에 이온빔 증착장비를 이용하여 기판 바이어스를 걸지 않은 경우와 -125 V의 기판 바이어스를 건 상태에서 증착하였다. 탄탈 박막내의 불순물 농도를 관찰하기 위해서 이차이온 질량분석기(secondary ion mass spectrometry)를 이용하였다. 세슘 클러스터 이온에 의한 깊이분석에서, -125 V의 기판 바이어스를 걸어줌으로써 산소, 탄소, 그리고 실리콘 불순물의 농도가 기판 바이어스를 걸지 않은 경우에 비해 상당히 감소한 것을 알 수 있었다. 또한, 세슘 이온빔과 산소 이온빔을 이용한 전체 불순물의 농도분포에서도, 음의 기판 바이어스가 박막 증착시 각각의 불순물 농도에 영향을 준다는 결과를 얻었고 이에 대한 고찰을 하였다. Ta films were deposited on Si (100) substrates at zero substrate bias voltage and a substrate bias voltage of -125 V ($V_{s}$ = -125 V) using a non-mass separated ion beam deposition system. To investigate the effect of the negative substrate bias voltage on the impurity concentration in the Ta films, secondary ion mass spectrometry (SIMS) was used to determine impurities in the Ta films. By the SIMS depth profiles with $Cs^{+}$ cluster ion beam, high intensities of O, C and Si were clearly found in the Ta film at $V_{s}$ = 0 V, whereas these impurities remarkably decreased in the Ta film at $V_{s}$ = -125 V. Furthermore, from the SIMS result with $Cs^{+}$ and $O_2^{+}$ ion beams, it was found that applying the negative substrate bias voltage could affect individual impurity contents in the Ta films during the deposition. Discussions concerning the effect of the negative substrate bias voltage on the impurity concentration of Ta films will be described in details.