• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 춘계학술발표대회 개요집
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• pp.193-195
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• 2003

Micro-structure and shear properties with reflow conditions, reflow temperature and time, for In-48Sn solder on BGA package were examined at the temperature between 140 and 170$^{\circ}C$ for 10 to 3600sec. With increasing reflow temperature and time, the thickness of intermetallic compound formed between solder and pad increased. Shear test indicated shear force increased in the range to a critical value of reflow time, and decreased over a critical reflow time. With increasing reflow temperature and time, the crater occurred on fracture surface because of a increase of crater by voids and IMC particles precipitated in solder.

• 반도체디스플레이기술학회지
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• 제5권3호
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• pp.29-32
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• 2006

Because of new requirements related to the employment of SMT(Surface Mounting Technology) manufacturing and the diversity of components on high density PCB(Printed Circuit Boards), Thermal control of the reflow process is required in order to achieve acceptable yields and reliability of SMT assemblies. Accurate control of the temperature distribution during the reflow process is one of the major requirements, especially in lead-free assembly. This study has been performed for reflow process using the commercial CFD(Computational Fluid Dynamics) tool for predicting flow and temperature distributions. Porous plate was installed to prevent leakage flow which was one of the major problem of temperature uniformity in the reflow process. There is a separation region where the flow is turned. Outside wall made of porous plate is to prevent and minimize separation region for acquiring uniform temperature during operation. This paper provided design concept from CFD results of the steady state temperature distribution and flow field inside a reflow oven.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.561-564
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• 2006

Because of new requirements related to the employment of SMT(Surface Mounting Technology) manufacturing and the diversity of components on high density PCB(printed circuit boards), Thermal control of the reflow process is required in oder to achieve acceptable yields and reliability of SMT assemblies. Accurate control of the temperature distribution during the reflow process is one of the major requirements, especially in lead-free assembly. This study has been performed for reflow process using the commercial CFD tool(Fluent) for predicting flow and temperature distributions. There was flow recirculation region that had a weak point in the temperature uniformity. Porous plate was installed to prevent and minimize flow recirculation region for acquiring uniform temperature in oven. This paper provided design concept from CFD results of the steady state temperature distribution and flow field inside a reflow oven.

• 한국재료학회지
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• 제9권5호
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• pp.538-543
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• 1999

금속 배선 공정에서 응용되고 있는 reflow에 관한 이론올 살펴보고, 금속 박막 reflow에 영향을 미치는 인자 및 re­flow와 grain growth의 관계를 고찰하였다. 금속 박막 reflow의 구동력은 표연 위치에 따른 chemical potential의 차이이며, 이러 한 구동력에 의하여 원자가 이동하게 된다. 반도체 소자의 금속 배선을 제작하는 조건에서 원자의 이동은 주로 surface diffusion에 의하여 이루어진다. 금속 박막의 reflow에 영향율 미치는 인자로는 reflow 온도, reflow 시간, reflow 분위기, 박막 두께, 박막 재료, underlayer 재료, 패턴 size, aspect ratio가 있으며, 박막을 reflow시키는 동안에 발생하는 grain growth에 의하여 reflow 특성이 변할 것으로 예상되므로 reflow 시 grain growth의 영향을 고려하여야 하리라 생각된다.

• 한국표면공학회지
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• 제38권1호
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• pp.28-36
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• 2005

In this study, the reflow characteristics of copper thin films which is expected to be used as interconnection materials in the next generation semiconductor devices were investigated. Cu thin films were deposited on the TaN diffusion barrier by metal organic chemical vapor deposition (MOCVD) and annealed at the temperature between 250℃ and 550℃ in various ambient gases. When the Cu thin films were annealed in the hydrogen ambience compared with oxygen ambience, sheet resistance of Cu thin films decreased and the breakdown of TaN diffusion barrier was not occurred and a stable Cu/TaN/Si structure was formed at the annealing temperature of 450℃. In addition, reflow properties of Cu thin films could be enhanced in H₂ ambient. With Cu reflow process, we could fill the trench patterns of 0.16～0.24 11m with aspect ratio of 4.17～6.25 at the annealing temperature of 450℃ in hydrogen ambience. It is expected that Cu reflow process will be applied to fill the deep pattern with ultra fine structure in metallization.

• 한국광학회지
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• 제20권2호
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• pp.118-122
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• 2009

PET 필름 위에 LCD 백라이트의 프리즘 집광시트의 역할을 대체 할 수 있는 microlens array(MLA) 시트를 설계하고 제작하였다. Photoresist thermal reflow 공정으로 두께 $100{\mu}m$ PET 필름 위에 MLA를 제작하였고, 노광 시간과 reflow의 온도, 시간 등의 변수에 따른 MLA의 형상 변화를 측정하였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년도 춘계 학술대회 개요집
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• pp.36-38
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• 2006

We investigated that the metallurgical, mechanical and electrical properties of the Sn-3.SAg/Cu ball grid array (BGA) solder joints at a reflow temperature of $255^{\circ}C$ for different reflow times of 10, 60, 300 and 1800 s. Two different intermetallic compound (IMC) layers, consisting of scallop-shaped $Cu_6Sn_5$ and very thin $Cu_3Sn$, formed at the solder/substrate interface, and their thicknesses increased with increasing reflow time. The shear force peaked after reflow for 60 s, and then significantly decreased with increasing reflow time. The fracture occurred along the solder ball in the initial reflow, but the fraction of the brittle fracture increased with increasing reflow time. The IMC growth and the volume of Cu dissolved in the solder balls affected the electrical property.

• 한국표면공학회지
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• 제39권6호
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• pp.255-262
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• 2006

Pd-Cu alloy membrane for hydrogen separation was fabricated by sputtering and Cu reflow process. At first, the Pd and Cu was continuously deposited by sputtering method on oxidized Si support, the Cu reflow process was followed. Microstructure of the surface and permeability of the membrane was investigated depending on various reflow temperature, time, Pd/cu composition and supports. With respect to our result, Pd-Cu thin film (90 wt.% Pd/10 wt.% Cu) deposited by sputtering process with thickness of $2{\mu}m$ was heat-treated for Cu reflow The voids of the membrane surface were completely filled and the dense crystal surface was formed by Cu reflow behavior at $700^{\circ}C$ for 1 hour. Cu reflow process, which is adopted for our work, could be applied to fabrication of dense Pd-alloy membrane for hydrogen separation regardless of supports. Ceramic or metal support could be easily used for the membrane fabricated by reflow process. The Cu reflow process must result in void-free surface and dense crystalline of Pd-alloy membrane, which is responsible for improved selectivity oi the membrane.

• 마이크로전자및패키징학회지
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• 제19권1호
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• pp.17-24
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• 2012

Recently, flip chip interconnection has been increasingly used in microelectronic assemblies. The common Flip chip interconnection is formed by reflow of the solder bumps. Lead-Tin solders and Tin-based solders are most widely used for the solder bump materials. However, the flip chip interconnection using these solder materials cannot be applied to temperature-sensitive components since solder reflow is performed at relatively high temperature. Therefore the development of low temperature bonding technologies is required in these applications. A few bonding techniques at low temperature of $150^{\circ}C$ or below have been reported. They include the reflow soldering using low melting point solder bumps, the transient liquid phase bonding by inter-diffusion between two solders, and the bonding using low temperature curable adhesive. This paper reviews various low temperature bonding methods.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 Proceedings of 5th International Joint Symposium on Microeletronics and Packaging
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• pp.17-17
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• 2000

The issue of reflow profiling continues to be a complex topic. The pains often associated with profiling can be reduced greatly if certain guidelines are followed and if there is a strong understanding of the variables that can be encountered during the reflow process. This paper shall discuss the appropriate guidelines and trouble shooting methods for reflow profiling, and in particular shall focus upon the benefits of implementing the linear ramp-to-spike profile. Delta T(T) is defined as the variation of temperature found on an assembly during the reflow process. Too large of a T can result in soldering defects, so to combat T a Ramp-Soak-Spike(RSS) reflow profile often is utilized. However, when using a newer-style reflow oven, the T often is minimized or eliminated, thus, the soak zone of the reflow profile becomes an unnecessary step. Because of this, the implementation of a linear Ramp-To-Spike(RTS) reflow profile should be considered. Benefits such as reduced energy costs, reduced solder defects, increased efficiency, improved wetting, and a simplification of the reflow profile process may be experienced when using the RTS profile. Included in this paper are the suggested process parameters for setting up the RSS and RTS profiles and the chemical and metallurgical reactions that occur at each set point of these profiles. The paper concludes with a discussion and pictures of several profile-related defects. Each of these defects is described, analyzed, and instructions are given for troublshooting these defects.