• Title/Summary/Keyword: Thermo-compression bonding

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Ultrasonic ACF Bonding Technique for Mounting LCD Driver ICs (LCD 구동 IC의 실장을 위한 초음파 ACF접합 기술)

  • Joung, Sang-Won;Yun, Won-Soo;Kim, Kyung-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.6
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    • pp.543-547
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    • 2008
  • In the paper, we develop the ultrasonic bonding technique for LCD driver chips having small size and high pin-density. In general, the mounting technology for LCD driver ICs is a thermo-compression method utilizing the ACF (An-isotropic Conductive Film). The major drawback of the conventional approach is the long process time. It will be shown that the conventional ACF method based on thermo-compression can be remarkably enhanced by employing the ultrasonic bonding technique in terms of bonding time. The proposed approach is to apply the ultrasonic energy together with the thermo-compression methodology for the ACF bonding process. To this end, we design a bonding head that enables pre-heating, pressure and ultrasonic excitation. Through the bonding experiments mainly with LCD driver ICs, we present the procedures to select the best combination of process parameters with analysis. We investigate the effects of bonding pressure, bonding time, pre-heating temperature before bonding, and the power level of ultrasonic energy. The addition of ultrasonic excitation to the thermo-compression method reduces the pre-heating temperature and the bonding process time while keeping the quality bonding between the LCD pad and the driver IC. The proposed concept will be verified and demonstrated with experimental results.

Chip on Glass Interconnection using Lateral Thermosonic Bonding Technology (횡방향 열초음파 본딩 기법을 이용한 COG 접합)

  • Ha, Chang-Wan;Yun, Won-Soo;Park, Keum-Saeng;Kim, Kyung-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.7
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    • pp.7-12
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    • 2010
  • In this paper, chip-on-glass(COG) interconnection with anisotropic conductive film(ACF) using lateral thermosonic bonding technology is considered. In general, thermo-compression bonding which is used in practice for flip-chip bonding suffers from the low productivity due to the long bonding time. It will be shown that the bonding time can be improved by using lateral thermosonic bonding in which lateral ultrasonic vibration together with thermo-compression is utilized. By measuring the internal temperature of ACF, the fast curing of ACF thanks to lateral ultrasonic vibration will be verified. Moreover, to prove the reliability of the lateral thermosonic bonding, observation of pressured mark by conductive particles, shear test, and water absorption test will be conducted.

Effects of Bonding Conditions on Mechanical Strength of Sn-58Bi Lead-Free Solder Joint using Thermo-compression Bonding Method (열압착 접합 조건에 따른 경·연성 인쇄회로기판 간 Sn-58Bi 무연솔더 접합부의 기계적 특성)

  • Choi, Ji-Na;Ko, Min-Kwan;Lee, Sang-Min;Jung, Seung-Boo
    • Journal of the Microelectronics and Packaging Society
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    • v.20 no.2
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    • pp.17-22
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    • 2013
  • We investigated the optimum bonding conditions for thermo-compression bonding of electrodes between flexible printed circuit board(FPCB) and rigid printed circuit board(RPCB) with Sn-58Bi solder as interlayer. In order to figure out the optimum bonding conditions, peel test of FPCB/RPCB joint was conducted. The peel strength was affected by the bonding conditions, such as temperature and time. The fracture energies were calculated through F-x (Force-displacement) curve during peel test and the relationships between bonding conditions and fracture behaviors were investigated. The optimum condition for the thermo-compression bonding with Sn-58Bi solder was found to be temperature of $195^{\circ}C$ and time of 7 s.

Design of flexure hinge to reduce lateral force of laser assisted thermo-compression bonding system (레이저 열-압착 본딩 시스템의 Lateral Force 감소를 위한 유연 힌지의 설계)

  • Lee, Dong-Won;Ha, Seok-Jae;Park, Jeong-Yeon;Yoon, Gil-Sang
    • Design & Manufacturing
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    • v.14 no.3
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    • pp.23-30
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    • 2020
  • Laser Assisted Thermo-Compression Bonding (LATCB) has been proposed to improve the "chip tilt due to the difference in solder bump height" that occurs during the conventional semiconductor chip bonding process. The bonding module of the LATCB system has used a piezoelectric actuator to control the inclination of the compression jig on a micro scale, and the piezoelectric actuator has been directly coupled to the compression jig to minimize the assembly tolerance of the compression jig. However, this structure generates a lateral force in the piezoelectric actuator when the compression jig is tilted, and the stacked piezoelectric element vulnerable to the lateral force has a risk of failure. In this paper, the optimal design of the flexure hinge was performed to minimize the lateral force generated in the piezoelectric actuator when the compression jig is tilted by using the displacement difference of the piezoelectric actuator in the bonding module for LATCB. The design variables of the flexure hinge were defined as the hinge height, the minimum diameter, and the notch radius. And the effect of the change of each variable on the stress generated in the flexible hinge and the lateral force acting on the piezoelectric actuator was analyzed. Also, optimization was carried out using commercial structural analysis software. As a result, when the displacement difference between the piezoelectric actuators is the maximum (90um), the maximum stress generated in the flexible hinge is 11.5% of the elastic limit of the hinge material, and the lateral force acting on the piezoelectric actuator is less than 1N.

Thermo-compression Bonding of Electrodes between RPCB and FPCB using Sn-Pb Solder (Sn-Pb 솔더를 이용한 경연성 인쇄 회로 기판간의 열압착 본딩)

  • Choi, Jung-Hyun;Lee, Jong-Gun;Yoon, Jeong-Won;Jung, Seung-Boo
    • Journal of the Microelectronics and Packaging Society
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    • v.17 no.3
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    • pp.11-15
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    • 2010
  • In this paper, we focused on the optimization of bonding conditions for the successful thermo-compression bonding of electrodes between the RPCB and FPCB with Sn-Pb solder. The peel strength was proportionally affected by the bonding conditions, such as pressure, temperature, and time. In order to figure out an optimized bonding condition, fracture energies were calculated through F-x (force-displacement) curves in the peel test. The optimum condition for the thermo-compression bonding of electrodes between the RPCB and FPCB was found to be temperature of $225^{\circ}C$ and time of 7 s, and its peel strength was 22 N/cm.

A method for estimating residual stress development of PCB during thermo-compression bonding process (PCB 열 압착 공정에서 잔류응력 계산을 위한 방법)

  • Lee, Sang-Hyuk;Kim, Sun-Kyung
    • 한국금형공학회:학술대회논문집
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    • 2008.06a
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    • pp.209-213
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    • 2008
  • In this work, we have proposed a method for calculating the residual stress developed during the PCB thermo-compression bonding precess. Residual stress is the most important factor that causes PCB warpage in accordance with the pattern design. In this work, a single-layed double-sided PCB, which is comprised of the dielectric (FR-4) substrate in the middle and copper cladding on the both top and bottom sides, is considered. A reference temperature, where all stress is free, is calculated by comparing the calculated and measured warapge of a PCB of which copper cladding of the top side is removed. Then, the reesidual stress values is calculated for the double-sided PCB.

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Effects of Bonding Conditions on Joint Property between FPCB and RPCB using Thermo-Compression Bonding Method (열압착법을 이용한 경.연성 인쇄회로기판 접합부의 접합 강도에 미치는 접합 조건의 영향)

  • Lee, Jong-Gun;Ko, Min-Kwan;Lee, Jong-Bum;Noh, Bo-In;Yoon, Jeong-Won;Jung, Seung-Boo
    • Journal of the Microelectronics and Packaging Society
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    • v.18 no.2
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    • pp.63-67
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    • 2011
  • We investigated effects of bonding conditions on the peel strength of rigid printed circuit board (RPCB)/ flexible printed circuit board (FPCB) joints bonded using a thermo-compression bond method, The electrodes on the FPCB were coated with Sn by a dipping process. We confirmed that the bonding temperature and bonding time strongly affected the bonding configuration and strength of the joints. Also, the peel strength is affected by dipping conditions; the optimum dipping condition was found to be temperature of $270^{\circ}C$ and time of 1s. The bonding strength linearly increased with increasing bonding temperature and time until $280^{\circ}C$ and 10s. The fracture energy calculated from the F-x (Forcedisplacement) curve during a peel test was the highest at bonding temperature of $280^{\circ}C$.

Wafer Level Bonding Technology for 3D Stacked IC (3D 적층 IC를 위한 웨이퍼 레벨 본딩 기술)

  • Cho, Young Hak;Kim, Sarah Eunkyung;Kim, Sungdong
    • Journal of the Microelectronics and Packaging Society
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    • v.20 no.1
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    • pp.7-13
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    • 2013
  • 3D stacked IC is one of the promising candidates which can keep Moore's law valid for next decades. IC can be stacked through various bonding technologies and they were reviewed in this report, for example, wafer direct bonding and atomic diffusion bonding, etc. As an effort to reduce the high temperature and pressure which were required for high bonding strength in conventional Cu-Cu thermo-compression bonding, surface activated bonding, solid liquid inter-diffusion and direct bonding interface technologies are actively being developed.