레이저 비전도성 페이스트(LNCP) 소재 최적화를 통한 상온 레이저 압착 접합(LABC) 기반 30 μm 피치 인터커넥션 신뢰성 향상

As the trend in advanced semiconductor packaging continues toward finer pitch and higherintegration, bonding technologies are increasingly expected to meet stricter thermal and mechanicalperformance requirements. However, conventional methods such as Thermo-Compression Bonding (TCB) oftenlead to problems including thermal stress, long processing times and limitations of fine-pitch bonding. Toovercome these challenges, this study introduces Room-Temperature Laser-Assisted Bonding with Compression(LABC), a next-generation bonding technique that enables localized heating and rapid cooling, minimizingthermal stress while improving alignment accuracy and process efficiency. To further enhance the electrical andmechanical reliability of LABC, we developed two types of Laser Non-Conductive Paste (LNCP), designatedLNCP-(A) and LNCP-(B). These eco-friendly materials, flux-free and solvent-free, not only prevent voidformation and fume generation but also eliminate the need for post-bond cleaning and underfill processes. Thebonding experiments were conducted on 30 μm-pitch daisy-chain bump structures formed on 11 mm × 7 mmsilicon chips, simulating High Bandwidth Memory (HBM). The glass transition temperatures (Tg) of LNCP-(A)and LNCP-(B) were measured to be 36.27 °C and 51.23 °C, respectively, via Differential Scanning Calorimetry(DSC). Following the bonding process, electrical resistance measurements, cross-sectional microstructuralanalysis, and temperature cycling (TC) tests were performed. LNCP-(B), with its higher Tg, exhibited improvedthermal stability and lower resistance variation compared to LNCP-(A). Furthermore, the LABC processeffectively suppressed intermetallic compound (IMC) growth, resulting in consistently thinner IMC thicknesscompared to those formed by TCB. In addition, shear strength testing confirmed the mechanical robustness ofthe bonded joints. These results demonstrate the effectiveness of LABC with optimized LNCP materials as apromising solution for high-reliability, fine-pitch interconnections in next-generation semiconductor packaging.