Effect of design parameters on novel high-aspect pin mounting process in advanced packaging based on design of experiment

The semiconductor industry's growing demand for advanced packaging in smaller devices has led to the adoption of high-aspect ratio Cu pins as an alternative to conventional solder bumps. This approach allows for higher density and increased terminals in applications like mobile phones and wearables. A novel mounting method for these pins involves repeated dropping onto the package surface using a specially designed 3D mask stencil, as traditional pick-and-place methods prove challenging due to the pins' aspect ratio. The efficiency of this process is evaluated through statistical analysis and simulation. A mounting simulation model is developed, incorporating pre-defined design parameters of the 3D mask at various levels. The response surface method is used to assess the impact of each design parameter on mounting efficiency and determine the optimal 3D mask design. The design of experiments considers three parameters (counter bore diameter, depth, and hole diameter) at three levels, with simulations repeated five times under each condition. Analysis results indicate that the hole diameter in the 3D mask is the most significant factor influencing mounting efficiency. To validate these findings, an experimental setup compares the number of mounted pins for each 3D mask design. The study concludes that optimizing the hole diameter, a crucial design parameter in the 3D mask, can substantially improve mounting efficiency in this innovative packaging approach.