• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.179-179
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• 2011

관통전극(TSV, Trough Silicon Via) 기술은 전자부품의 소형화, 고성능화, 생산성 향상을 이룰 수 있는 기술이다. Cu는 현재 배선 기술에 적용되고 있고 전기적 저항이 낮아서 TSV filling 재료로 사용된다. 하지만 확산 방지막에 의해 완벽히 감싸지지 않는다면, Cu+은 빠르게 절연막을 통과하여 Si 웨이퍼로 확산된다. 이런 현상은 절연막의 누설과 소자의 오동작 등의 신뢰성 문제를 일으킬 수 있다. 현재 TSV의 제조와 열 및 기계적 응력에 관한 연구는 활발히 진행되고 있으나 Biased-Thermal Stress(BTS) 조건하의 Cu 확산에 관한 연구는 활발하지 않는 것이 실정이다. 이를 위해 본 연구에서는 TSV용 Cu 확산 방지막 Ti에 대해 Cu+의 drift 억제 특성을 조사하였다. 실험을 위해 Cu/확산 방지막/Thermal oxide/n-type Si의 평판 구조를 제작하였고 확산 방지막의 두께에 따른 영향을 조사하기 위해 Ti의 두께를 10 nm에서 100 nm까지 변화하였으며 기존 Cu 배선 공정에서 사용되는 확산 방지막 Ta와 비교하였다. 그리고 Cu+의 drift 측정을 위해 Biased-Thermal Stress 조건(Thermal stress: $275^{\circ}C$, Bias stress: +2MV/cm)에서 Capacitance 및 Timedependent dielectric breakdown(TDDB)를 측정하였다. 그 결과 Time-To Failure(TTF)를 이용하여 Cu+의 drift를 측정할 수 있었으며, 확산 방지막의 두께가 증가할수록 TTF가 증가하였고 물질에 따라 TTF가 변화하였다. 따라서 평판 구조를 이용한 본 실험의 Cu+의 drift 측정 방법은 향후 TSV 구조에서도 적용 가능한 방법으로 생각된다.

• Korean Journal of Materials Research
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• v.17 no.10
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• pp.509-515
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• 2007

In order to fabricate adhesiveless 2-layer flexible copper clad laminate (FCCL) used for COF (chip on film) with high peel strength, polyimide (PI; Kapton-EN, $38\;{\mu}m$) surface was modified by reactive $O_2^+$ and $N_2O^+$ ion beam irradiation. 300 mm-long linear electron-Hall drift ion source was used for ion irradiation with ion current density (J) higher than $0.5\;mA/cm^2$ and energy lower than 200 eV. By vacuum web coating process, PI surface was modified by linear ion source and then 10-20 nm thick Ni-Cr and 200 nm thick Cu film were in-situ sputtered as a tie layer and seed layer, respectively. Above this sputtered layer, another $8-9{\mu}m$ thick Cu layer was grown by electroplating and subsequently acid and base resistance and thermal stability were tested for examining the change of peel strength. Peel strength for the FCCLs treated by both $O_2^+$ and $N_2O^+$ ion irradiation showed similar magnitudes and increased as the thickness of tie layer increased. FCCL with Cu (200 nm)/Ni-Cr (20 nm)/PI structure irradiated with $N_2O^+$ at $1{\times}10^{16}/cm^2$ ion fluence was proved to have a strong peel strength of 0.73 kgf/cm for as-received and 0.34 kgf/cm after thermal test.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.23-29
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• 2014

Less power consumption, lower cost, smaller size and more functionality are the increasing demands for consumer electronic devices. The three dimensional(3-D) TSV packaging technology is the potential solution to meet this requirement because it can supply short vertical interconnects and high input/output(I/O) counts. Cu(Copper) has usually been chosen to fill the TSV because of its high conductivity, low cost and good compatibility with the multilayer interconnects process. However, the CTE mismatch and Cu ion drift under thermal stress can raise reliability issues. This study discribe the thermal stress reliability trend for successful implementation of 3-D packaging.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.4
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• pp.111-115
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• 2014

Effect of dynamic electric fields on dielectric breakdown behavior in Cu damascene interconnects was investigated. Among the DC, unipolar, and bipolar pulse conditions, the longest dielectric lifetime is observed under the bipolar condition because backward Cu ion drift occurs when the direction of electric field is changed by 180 degrees and Cu contamination is prohibited as a results. Under the unipolar pulse condition, the dielectric lifetime increases as pulse frequency increases and it exceed the lifetime under DC condition. It suggests that the intrinsic breakdown of dielectrics significantly affect the dielectric breakdown in addition to Cu contamination. As the unipolar pulse width decreases, dielectric bond breakdown is more difficult to occur.