• 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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• 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.

• 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.

• 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.

• 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.

• 마이크로전자및패키징학회지
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• 제27권3호
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• pp.35-39
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• 2020

Nonwet (Head in Pillow) 불량은 SMT(surface mount technology) 공정 불량 유형 중 하나로 이 불량은 solder paste misalign, reflow 조건, package warpage, package ball size 등과 같은 인자에 따라 불량이 발생을 한다. 이에 본 논문은 Nonwet 발생 인자 중 ① reflow 조건 ② package ball & solder paste misalign ③ package ball 크기 type에 대한 인자를 선정하여 nonwet 실험을 진행하였다. 먼저 reflow 조건의 경우 soldering 시간이 길 경우 nonwet risk가 증가를 하나, reflow 공정에 N₂를 적용할 시 solder ball 산화 억제에 따른 nonwet 개선을 확인 할 수 있었다. 또한 package ball과 solder paste misalign 발생 시 ball과 paste의 접촉 깊이가 20 ㎛ 이하의 경우 nonwet에 취약 했으며, package ball 체면적이 작을수록 nonwet 관점 개선됨을 확인 할 수 있었다.

• 마이크로전자및패키징학회지
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• 제14권3호
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• pp.43-49
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• 2007

웨이퍼 레벨 솔더범핑시 under bump metallurgy (UBM)의 종류와 리플로우 시간에 따른 Sn 솔더범프의 평균 금속간화합물 층의 두께와 UBM의 소모속도를 분석하였다. Cu UBM의 경우에는 리플로우 이전에 $0.6\;{\mu}m$ 두께의 금속간화합물 층이 형성되어 있었으며, $250^{\circ}C$에서 450초 동안 리플로우함에 따라 금속간화합물 층의 두께가 $4\;{\mu}m$으로 급격히 증가하였다. 이에 반해 Ni UBM에서는 리플로우 이전에 $0.2\;{\mu}m$ 두께의 금속간화합물 층이 형성되었으며, 450초 리플로우에 의해 금속간화합물의 두께가 $1.7\;{\mu}m$으로 증가하였다. Cu UBM의 소모속도는 15초 리플로우시에는 100 nm/sec, 450초 리플로우시에는 4.5 nm/sec이었으나, Ni UBM에서는 소모속도가 15초 리플로우시에는 28.7 nm/sec, 450초 리플로우시에는 1.82 nm/sec로 감소하였다.

• 한국재료학회지
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• 제9권2호
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• pp.124-131
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• 1999

Copper film, which is expected to be used as interconnection material for 1 giga DRAM integrated circuits was deposited on hole and trench patterns by Metal Organic Chemical Vapor Deposition(MOCVD) method. After a reflow process, contact and L/S patterns were filled by copper and the characteristics of the Cu reflow process were investigated. When deposited Cu films were reflowed, grain growth and agglomeration of Cu have occurred in surfaces and inner parts of patterns as well as complete filling in patterns. Also Cu thin oxide layers were formed on the surface of Cu films reflowed in $O_2$ambient. Agglomeration and oxidation of Cu had bad influence on the electrical properties of Cu films especially, therefore, their removal and prevention were studied simultaneously. As a pattern size is decreased, preferential reflow takes place inside the patterns and this makes advantages in filling patterns of deep submicron size completely. With Cu reflow process, we could fill the patterns with the size of deep sub-micron and it is expected that Cu reflow process could meet the conditions of excellent interconnection for 1 giga DRAM device when it is combined with Cu MOCVD and CMP process.

• Journal of Welding and Joining
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• 제19권3호
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• pp.311-316
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• 2001

This paper presents that the affecting factors to the solderability and initial reliability. It is the factor that the coefficient of thermal expansion between package and PCB(Printed Circuit Board), the quantity of solder paste and reflow condition, and Au thickness of the solder ball pad on polyimide tape. As the reflow soldering condition for 48 ${\mu}BGA$ is changed, it is estimated that the quantity of Au diffusion at eutectic Sn-Pb solder surface and initial bonding strength of eutectic Sn-Pb solder and lead free solder. It is the result that quantitative measurement of Au diffusion quantity is difficult, but the shear strength of eutectic Sn-Pb solder joint is 842 mN at first reflow and increases 879 mN at third reflow. The major failure mode in solder is judged solder fracture. So, Au diffusion quantity is more affected by reflow temperature than by the reflow times.