The oxidation control of copper leadframe package for prevention of popcorn cracking

Takano, E.; Mino, T.; Takahashi, Kenji; Sawada, K.; Shimizu, Sachio; Yoo, Hee Yeoul

doi:10.1109/ectc.1997.606149

Cited by 38 publications

(10 citation statements)

References 4 publications

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“…Some research shows chemical oxidation through acidic or alkaline solution is preferred over thermal method because the morphological modification obtained from chemical method to give better adhesion [3]. Findings suggested that optimum oxide thickness was proposed as 20-40nm reported from Tankano et al [4] and 20-30nm from Cho et al [5]. With the optimized oxidation method, the interfacial adhesion has been enhanced from almost zero to 100Jm -2 from Lee's study [6].…”

Section: Introductionmentioning

confidence: 84%

“…Kim, et al demonstrates the interfacial integrity of black oxide treatment decreased 83.1% after aging at 121 o C/100%RH chamber for 120 hours [7]. Takano, et al study showed, when the sample were preconditioned under 85 o C/85%RH, 168hr, 41.7% decrease appeared in button shear test [4]. The SAM P treated sample is the only one showing no drop in interfacial fracture toughness.…”

Section: Figure 7 Comparison Of Fracture Toughness Drop From Differementioning

confidence: 93%

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Thiol based self assembly molecular layer for reliable Cu-epoxy interface

Wong

2010

2010 Proceedings 60th Electronic Components and Technology Conference (ECTC)

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This paper focuses on the use of new hydrophobic thiol based molecular as adhesion promoter for copper-epoxy interfacial adhesion improvement. The motivation of this study is the long term interfacial adhesion reliability under moisture environment. In order to solve this problem, our group introduced the use of thiol-based molecules (SAM P) having hydrophobic characteristic as adhesion promoter through solution deposition. The rationale is to reduce the moisture uptake and hinder the diffusion into the interface. Long alkyl chains structure is intended to provide hydrophobic characteristic of the interface. A reactive hydroxyl group which can achieve covalent bonds with the epoxy system is designed as an end group. This study aims at deriving new hydrophobic SAM layer to tackle the moisture reliability problem of the Cu-epoxy interface. Systematic study on the SAM P treated interface is conducted. SEM and XPS are applied for surface analysis. DI water contact angle using sessile drops is used to quantify the hydrophobicity of the interface. To evaluate the interfacial adhesion with SAM P treatment, copper jigs bonded with an epoxy underfill are tested by the tapered double cantilever beams (TDCB) setup. The interfacial toughnesses (G IC ) are recorded of both fresh samples and samples after 85 o C/85%RH humidity chamber preconditioning. With the hydrophobic treated interfaces, our preliminary results demonstrated that G IC of the interface changes slightly from 117.7±29.4 Jm -2 to 118.3±7.0Jm -2 for the fresh samples and moisture preconditioning ones respectively. The results are compared with samples obtained from previous SAM treatment. The results show that with the SAM P treatment, the interface is resistant to moisture environment. The test results will help to establish the guidelines in formation of SAM for a reliable copper-epoxy interface.

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Section: Introductionmentioning

confidence: 84%

Section: Figure 7 Comparison Of Fracture Toughness Drop From Differementioning

confidence: 93%

Thiol based self assembly molecular layer for reliable Cu-epoxy interface

Wong

2010

2010 Proceedings 60th Electronic Components and Technology Conference (ECTC)

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“…Takano et al [5] reported that the optimum thickness of copper oxides was 20-40nm. As for package assembly, however, the copper oxidation occurs predominantly in processes such as die attach, wire bonding, EMC curing, etc.…”

Section: Introductionmentioning

confidence: 99%

Electroless plating copper cones on leadframe to improve the adhesion with epoxy molding compound

Zhang

Lü

Hang

et al. 2012

2012 13th International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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A simple method to increase the adhesion strength between leadframe and epoxy molding compound (EMC) was reported in this paper. Cone-structured copper film was deposited on copper-based leadframe sheets by electroless plating. SEM observation of the as-prepared film indicates that cone size distinctly depends on plating time. Adhesion strength between EMC and cone-coated leadframe was measured by button shear test (BST). Results show that when deposition time t::;120s, the adhesion strength increases rapidly with the growth of copper cones, when t > 120s, although cones keep growing, the adhesion strength tends to level off. Average adhesion strength reaches maximum value of 33.80(±1.74) MPa, increased by 87% (57%�124%) when substrate was plated for 600s, compared with that of conventional leadframe. By observing leadframe side of fracture surface after destructive button shear test, two failure modes were proposed: failure at interface and inside EMC. It is assumed that the copper nano-cones structure could effectively increase the contact area of EMC and leadframe, which leads to mechanical interlocking. Such micro-nano structure and its unique property are expected to be applied in the practical industry.

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“…Extensive investigation was carried out on the influence of copper oxide thickness on adhesion strength. The findings [4,51 suggested that cupric oxide (CuO) which resulted in needle-like morphology played a dominant role in copperEMC interfacial seen@ and a control of oxide thickness was essential for the success of Cu-epoxy adhesion property. Control of copper oxide thickness is difficult precluding it as a practical method €or adhesion enhancement.…”

Section: Introductionmentioning

confidence: 99%

Investigation of adhesion proper-ties of Cu-EMC interface by molecular dynamic simulation

Wong

Fan

Yuen

EuroSimE 2005. Proceedings of the 6th International Conference on Thermal, Mechanial and Multi-Physics Simulation and Experimen

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Cu-EMC (Copper-Epoxy Molding Compound) interface is known to be the weakest joint in the electronic packages, which causes delamination during reliability test. A prime reason is the lack of adhesion between Cu and epoxy compound. To solve the problem, self-assembly monolayer ( S A M ) is used to improve adhesion of copper-epoxy system. This paper focuses on simulation of adhesion in Cu-SAM-EMC system.In this study, molecular models of bi-material system, which consists of S A M and Cu, were built to evaluate the adhesion force of the Cu-SAM system. Interfacial energy density was derived lkom molecular dynamics (MD) simulation. The newly developed condensed phase optimization molecular potentials for atomistic simulation studies (COMPASS) force field enables prediction of adhesive strength of bi-material system in organic-metal oxide interface. The MD results were compared against: shear load obtained fiom button shear tests. It has been illustrated that MD can provide a reasonable qualitatively prebction of the relative interfacial strength of the selected S A M samples. It is concluded that MD is an effective tool in screening SAM candidates.

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The oxidation control of copper leadframe package for prevention of popcorn cracking

Cited by 38 publications

References 4 publications

Thiol based self assembly molecular layer for reliable Cu-epoxy interface

Thiol based self assembly molecular layer for reliable Cu-epoxy interface

Electroless plating copper cones on leadframe to improve the adhesion with epoxy molding compound

Investigation of adhesion proper-ties of Cu-EMC interface by molecular dynamic simulation

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