• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.129-133
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• 2005

대기압 글로우 플라즈마를 이용하여 반도체 리드프레임(Alloy 42) 도금 전처리 습식 공정을 건식으로 대체하였다. 13.56 MHz의 RF 전원을 사용하여 300 W 파워에서 안정적인 대기압 글로우 플라즈마를 발생시켰으며, 금속 리드프레임에 플라즈마가 직접 접촉해도 아크나 스트리머 발생이 없었다. 플라즈마 소스 가스로는 알곤(Ar)을 사용하였으며, 활성가스로 산소($O_2$)를 첨가하였다. 300 W 파워에서 산소를 50 sccm 공급하고 100 mm/sec 속도로 리드프레임을 처리한 결과, 처리 전 접촉각이 $82^{\circ}$에서 처리 후 $10^{\circ}$ 이하로 낮아졌다. 플라즈마 처리 후 리드프레임 표면 거칠기 변화를 AFM으로 측정하였다.

• Korean Journal of Materials Research
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• v.7 no.9
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• pp.781-788
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• 1997

Cu/EMC 계면 접착력에 미치는 산화의 규명하기 위해 리드프레임의 저온 산화에 대하여 조사하였다. 이전의 보고와 달리, 저온에서도 Cu$_{2}$O위에 CuO산화물이 형성되어 Cu/Cu$_{2}$O(NiO)/Cu(NiO)/air의 산화층 구조를 나타내었다. Cu/EMC 계면 접착력은 산화가 진행됨에 따라 산화 초기에 급격히 증가하다 최대값에 이르고, 이후의 계속적인 산화로 감소하는 양상을 보였다. 접착력은 산화 온도나 리드프레임의 종류보다 산화막의 두께에 밀접한 상관 관계를 나타내었다. 최대 계면 접착력이 얻어지는 산화막의 두께는 리드프레임의 종류보다 산화막의 두께에 밀접한 상관 관계를 나타내었다. 최대 계면 접착력이 얻어지는 산화막의 두께는 리드프레임의 종류와 무관하게 대략 20nm 와 30nm 사이에 존재하였다. 산화 초기의 접착력 증가는 산화로 인한 EMC에 대한 젖음성의 증가와 기계적 고착 효과의 증가에 기인하였다. 리드프레임과 EMC의 파괴 표면에 대한 AES, XPS 분석으로 부터, 산화막의 두께가 얇을 때에는 Cu$_{2}$O//CuO의 계면 파괴 + EMC 자체 파괴가 복합적으로 발생함을 알 수 있었다. 반면에 과도한 산화로 낮을 접착력을 나타내는 시편은 Cu/Cu$_{2}$/O 계면의 파괴를 나타냈다.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.19-24
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• 2001

The lead frame, which is principal material used in semiconductor packaging, is required to be microscopic in leads and pitches to cope with miniaturization, thin film, large scale integrated. In addition, it is indispensable to eliminate residual stress and burrs occurring at manufacturing lead frames This thesis applied electrolytic abrasion in order to remove burrs and residual stress created during the stamp process. Electrolytic abrasion removed the burrs on the surface of lead frame. Removal of residual stress highly depends on the types of electrolyte solution. In case of perchloric system, electrolytic abrasion removed 23% of residual stress. Through removal of burrs and reducing residual stress, the reliability of lead frame was substantially improved.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.992-999
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• 1999

Due to the inherently poor adhesion strength of Cu-based leadframe/EMC(Epoxy Molding Compound) interface, popcorn-cracking phenomena of thin plastic packages frequently occur during the solder reflow process. In this study, in order to enhance the adhesion strength of Cu-based leadframe/EMC interface, brown-oxide layer was formed on the leadframe surface by immersing of leadframe sheets in hot alkaline solution, and the adhesion strength of leadframe/EMC interface was measured by using SDCB(Sandwiched Double Cantilever Beam) and SBN(Sandwiched Brazil-Nut) specimens. Results showed that brown oxide treatment of leadframe introduced fine acicular CuO crystals on the leadframe surface and improved the adhesion strength of leadframe/EMC interface. Enhancement of adhesion strength was directly related to the thickening kinetics of oxide layer. This might be due to the mechanical interlocking of fine acicular CuO crystals into EMC.

• Journal of Adhesion and Interface
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• v.23 no.4
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• pp.108-115
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• 2022

In this study, we synthesized poly(itaconic acid-co-acrylamide) (IAcAAM) used as a novel polymer adhesion promoter to improve the adhesion strength of surface-treated Cu lead frames and epoxy composites. IAcAAM comprising itaconic acid, acrylamide was prepared through radical aqueous polymerization. The chemical structure and properties of IAcAAM was analyzed by FT-IR, ¹H-NMR, GPC, and DSC. The surface of the copper lead frame was treated with high temperature, alkali, and UV ozone to reduce the water contact angle and increase the surface energy. The adhesive strength of Cu lead frame and epoxy composite increased with the decrease of contact angle. The adhesive strength of Cu lead frame/epoxy composite increased with the addition of IAcAAM in epoxy composite. As silica content increased, the adhesive strength of Cu lead frame and epoxy composite tended to slightly decrease.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.4
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• pp.67-72
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• 2001

An Effort has been made to more accurately analyze the flow in the chip cavity, particularly to model the flow through the openings in the leadframe and correctly treat the thermal boundary condition at the leadframe. The theoretical analysis of the flow has been done by using the Hele-Shaw approximation in each cavity separated by a leadframe. The cross-flow through the openings in the leadframe has been incorporated into the Hele-Shaw formulation as a mass source term. The optimization program based on the complex method integrated with flow analysis program has been successfully used to obtain the optimal filling conditions to avoid short shot.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.97-103
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• 2000

This paper deals with residual stresses induced at the viscoelastic adhesive layer between the semiconductor chip and the leadframe during adhesion process. The adhesive layer has been assumed to be“thermorheologically simple”. The time-domain boundary element method(BEM) has been employed to investigate the behavior of interface stresses. Numerical results show that very large stress gradients are present at the interface corner and such singularity might lead to local yielding or edge delamination.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.5
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• pp.147-156
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• 2001

본 연구에서는 칩 캡슐화 성형 공정 중의 패들 변형을 해석하기 위한 방법론이 연구되었다. 헬레쇼오 근사 모델에 근거한 유한요소법이 칩 캐비티에서의 유동 해석을 위해 사용되었다. 리드 프레임 상의 구멍을 통한 통과 유동해석을 위한 근사모델이 제안되었다. 본 연구에서 제시된 해석모델에 의해 계산된 값과 실험 값은 잘 일치하였다. 유동해석을 통하여 리드프레임과 패들에 의해 경계를 이루고 있는 상, 하 캐비티간의 압력차가 계산되었다. 최종적으로 패들 변형이 압력차 계산 값을 이용하여 계산되게 된다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.256-257
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• 2003

반도체 와이어 본딩(wire-bonding) 조립공정에 사용되는 검사용 현미경 광학계를 설계하였다. 이러한 와이어는 리드프레임에 대해 $\pm$ 1 mm의 단차를 가진다. 이 때 리드프레임은 6배로 관찰하며, 와이어 부분은 2배로 관찰하고자 한다. 그러나 와이어의 단차로 인해 물체거리가 변하게 되며, 일반 광학계로는 배율도 변하게 된다. 물체거리가 변해도 동일한 배율을 가지는 광학계를 설계하기 위해 유한 물점용 3군 줌 광학계를 목적에 맞게 변형시켰다. (중략)

• Journal of the Microelectronics and Packaging Society
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• v.20 no.3
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• pp.31-35
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• 2013

TSOP(Thin Small Outline Package) is the IC package using lead frame, which is the type of low cost package for white electronics, auto mobile, desktop PC, and so on. Its performance is not excellent compared to BGA or flip-chip CSP, but it has been used mostly because of low price of TSOP package. However, it has been issued in TSOP package that thermal deflection of lead frame occurs frequently during molding process and Au wire between semiconductor die and pad is debonded. It has been required to solve this problem through substituting materials with low CTE and improving structure of lead frame. We focused on developing the lead frame structure having thermal stability, which was carried out by numerical analysis in this study. Thermal deflection of lead frame in TSOP package was simulated with positions of anti-deflection adhesives, which was ranging 198 um~366 um from semiconductor die. It was definitely understood that thermal deflection of TSOP package with anti-deflection adhesives was improved as 30.738 um in the case of inside(198 um), which was compared to that of the conventional TSOP package. This result is caused by that the anti-deflection adhesives is contributed to restrict thermal expansion of lead frame. Therefore, it is expected that the anti-deflection adhesives can be applied to lead frame packages and enhance their thermal deflection without any change of substitutive materials with low CTE.