Laser-Based Selective Removal of EMI Shielding Layers in System-in-Package (SiP) Modules.

Area of Science:

• Materials Science
• Electrical Engineering
• Manufacturing Technology

Background:

• Increasing complexity in System-in-Package (SiP) technologies drives demand for selective electromagnetic interference (EMI) shielding.
• Conventional sputtering for EMI shielding lacks selectivity and requires additional masking or post-processing.

Purpose of the Study:

• To propose and validate a novel laser-based approach for selective removal of EMI shielding layers.
• To investigate the thermal and mechanical effects of laser irradiation on multilayer shielding structures.

Main Methods:

• Numerical simulations of thermal and mechanical behavior under full-area and laser scanning irradiation.
• Experimental validation using a nanosecond pulsed fiber laser for selective layer removal.
• Optimization of laser power and scanning speed for effective delamination without substrate damage.

Main Results:

• Laser scanning induced higher interfacial shear stress (38.6 MPa) than full-area irradiation (12.5 MPa), promoting delamination.
• Optimized laser power (~6 W) and scanning speed (50 mm/s) achieved complete shielding removal without damaging the epoxy mold compound (EMC).
• Excessive laser power (8 W) led to material degradation, highlighting the importance of parameter optimization.

Conclusions:

• A non-contact, damage-free, and selective laser-based method for EMI shielding removal is feasible.
• This technique offers a promising solution for next-generation semiconductor packaging requiring precise EMI control.
• The study demonstrates efficient material processing with minimal irradiation time (0.14 s).