A Novel Approach for High Precision Printing of Micro-Bumps

High aspect ratio micro-bumps play a critical role in flip chip applications, facilitating enhanced pixel density and reduced pixel-to-pixel coupling noise. The necessity for micro-bumps with a diameter of less than 5 um, featuring these high aspect ratios, underscores the limitation of conventional technologies. This study discussed how HPCAP (High Precision Capillary Printing) Technology, allows the one-step fabrication of such micro-bumps. HPCAP capitalizes on capillary forces and resonance as intrinsic drivers, preventing the requirement for external energy sources. Inspired by Atomic Force Microscopy (AFM), this technique achieves remarkable precision, with up to 5 nm accuracy along the Z-axis and 20 nm along the XY axes. This level of precision ensures impeccable control over the dimensions and shapes of the micro-bumps enabling exceptional versatility in design, dimensions, and choice of materials.