Application of metal interconnection process with micro-LED display by laser-assisted bonding technology

Tian, Wenya; Ma, Zehao; Cao, Xuan; Lin, Jiahua; Cui, Yongxin; Huang, Xiuqi

doi:10.1007/s10854-023-11549-6

Cited by 2 publications

(2 citation statements)

References 25 publications

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“…Zhao et al transferred the AlGaInP epitaxial layer onto a silicon substrate using In-Ag bonding technology and epitaxial layer stripping process [18]. The metal bump materials on Micro-LED chips are mainly composed of metals such as Au and Sn [19,20]. This presents two issues.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and bonding of In bumps on Micro-LED with 8 μm pixel pitch

Jiang,

Chen,

Zhang

et al. 2024

Eng. Res. Express

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Indium (In) is currently used to fabricate metal bumps on micro-light-emitting diode (Micro-LED) chips due to its excellent physical properties. However, as Micro-LED pixel size and pitch decrease, achieving high-quality In bumps on densely packed Micro-LED chips often presents more challenges. This paper describes the process of fabricating In bumps on micro-LEDs using thermal evaporation, highlighting an issue where In tends to grow laterally within the photoresist pattern, ultimately blocking the pattern and resulting in undersized and poorly dense In bumps on the Micro-LED chip. To address this issue, we conducted numerous experiments to study the height variation of In bumps within a range of photoresist aperture sizes (3 μm -7 μm) under two different resist thickness conditions (3.8 μm and 4.8 μm). The results showed that the resist thickness had a certain effect on the height of In bumps on the Micro-LED chip electrodes. Moreover, we found that, with the photoresist pattern size increasing under constant resist thickness conditions, the height and quality of the bumps significantly improved. Based on this finding, we rationalized the adjustment of the photoresist pattern size within a limited emission platform range to compensate for the height difference of In bumps caused by different resist thicknesses between the cathode and anode regions. Consequently, well-shaped and dense In bumps with a maximum height of up to 4.4 μm were fabricated on 8 μm pitch Micro-LED chips. Afterwards, we bonded the Micro-LED chip with indium bumps to the CMOS chip, and we found that we could successfully control the CMOS chip to drive the Micro-LED chip to display specific characters through the Flexible Printed Circuit (FPC). This work is of significant importance for the fabrication of In bumps on Micro-LED chips with pitches below 10 μm and subsequent bonding processes.

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Section: Introductionmentioning

confidence: 99%

Fabrication and bonding of In bumps on Micro-LED with 8 μm pixel pitch

Jiang,

Chen,

Zhang

et al. 2024

Eng. Res. Express

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“…LAB technology, exploiting a laser wavelength that exhibits heightened absorption characteristics in Si chips relative to polymer materials, offers the notable advantage of mitigating substrate heating and minimizing warpage [8][9][10]. Through decades of dedicated research, a repertoire of materials and methodologies applicable to LAB, including flux-free underfills, has been cultivated.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Optimization of Sn-58Bi Low-Temperature Solder Fabricated by Intense Pulsed Light (IPL) Irradiation

Go,

Noh,

Jung

et al. 2024

Crystals

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In this study, intense pulsed light (IPL) soldering was employed on Sn-58Bi solder pastes with two distinct particle sizes (T3: 25–45 μm and T9: 1–8 μm) to investigate the correlation between the solder microstructure and mechanical properties as a function of IPL irradiation times. During IPL soldering, a gradual transition from an immature to a refined to a coarsened microstructure was observed in the solder, impacting its mechanical strength (hardness), which initially exhibited a slight increase followed by a subsequent decrease. It is noted that hardness measurements taken during the immature stage may exhibit slight deviations from the Hall–Petch relationship. Experimental findings revealed that as the number of IPL irradiation sessions increased, solder particles progressively coalesced, forming a unified mass after 30 sessions. Subsequently, after 30–40 IPL sessions, notable voids were observed within the T3 solder, while fewer voids were detected at the T9-ENIG interface. Following IPL soldering, a thin layered structure of Ni3Sn4 intermetallic compound (IMC) was observed at the Sn-58Bi/ENIG interface. In contrast, reflow soldering resulted in the abundant formation of rod-shaped Ni3Sn4 IMCs not only at the reaction interface but also within the solder bulk, accompanied by the notable presence of a P-rich layer beneath the IMC.

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Application of metal interconnection process with micro-LED display by laser-assisted bonding technology

Cited by 2 publications

References 25 publications

Fabrication and bonding of In bumps on Micro-LED with 8 μm pixel pitch

Fabrication and bonding of In bumps on Micro-LED with 8 μm pixel pitch

Microstructural Optimization of Sn-58Bi Low-Temperature Solder Fabricated by Intense Pulsed Light (IPL) Irradiation

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