Backside Laminate Removal of Wafer-Level Packaging (WLP) Devices Mounted on Board
Backside Laminate Removal of Wafer-Level Packaging (WLP) Devices Mounted on Board
Thursday, October 8, 2026: 8:20 AM
Summary:
Demounting and mounting of IC devices on printed circuit boards (PCBs) are commonly performed for electrical verification and functional testing. Devices with bumps or solder balls, such as Ball Grid Array (BGA) and Wafer-Level Packaging (WLP) devices require reballing during these processes, which involves repeated heat exposure that can induce stress and potential damage. Traditional backside laminate removal methods, including mechanical and chemical techniques, are either time-consuming or risk damaging the die or PCB. This study demonstrates laser ablation as a method for backside laminate removal of WLP devices while remaining mounted on the PCB. Optical and infrared (IR) imaging confirmed complete exposure of the die backside without scratches, chip-out, or PCB damage. Curve trace testing (CT) before and after the process showed no change in electrical characteristics, indicating preserved device functionality. By eliminating repeated demounting, mounting, and reballing, this technique minimizes thermal and mechanical stress, preserving structural and electrical integrity. Laser laminate removal offers a faster, efficient, and safe solution for fault isolation preparation in failure analysis, addressing the limitations of conventional methods while maintaining both device and PCB functionality.
Demounting and mounting of IC devices on printed circuit boards (PCBs) are commonly performed for electrical verification and functional testing. Devices with bumps or solder balls, such as Ball Grid Array (BGA) and Wafer-Level Packaging (WLP) devices require reballing during these processes, which involves repeated heat exposure that can induce stress and potential damage. Traditional backside laminate removal methods, including mechanical and chemical techniques, are either time-consuming or risk damaging the die or PCB. This study demonstrates laser ablation as a method for backside laminate removal of WLP devices while remaining mounted on the PCB. Optical and infrared (IR) imaging confirmed complete exposure of the die backside without scratches, chip-out, or PCB damage. Curve trace testing (CT) before and after the process showed no change in electrical characteristics, indicating preserved device functionality. By eliminating repeated demounting, mounting, and reballing, this technique minimizes thermal and mechanical stress, preserving structural and electrical integrity. Laser laminate removal offers a faster, efficient, and safe solution for fault isolation preparation in failure analysis, addressing the limitations of conventional methods while maintaining both device and PCB functionality.