Precision Laser Drilling for High-Quality Custom Probe Cards

As advanced packaging and Chiplet testing evolve, the I/O density of chips is skyrocketing. Faced with IC testing arrays containing tens of thousands of pins, traditional mechanical drilling falls short. Powered by high-stability femtosecond laser micro-machining, MONO successfully overcomes industry bottlenecks in ceramic substrates, delivering high aspect ratios, zero taper, and ultra-small R-corners.

The Critical Role of Probe Cards in Wafer Sort

In the Wafer Sort process, probe cards are the critical components that enable high-density, high-precision electrical testing. As semiconductor process nodes continue to shrink, the global demand from top-tier testing houses for High-Quality Custom Probe Cards is surging.

The true barrier to manufacturing these premium probe cards lies in the micro-drilling quality of the probe card substrate and the guide plate. If the micro-holes suffer from poor roundness or taper errors, it disrupts the coaxial alignment between the probe and the hole wall. This leads to stuck or broken probes and, ultimately, costly equipment downtime. To address this severe semiconductor test interface challenge, MONO has delivered a groundbreaking solution backed by mass-production data.

A smaller corner radius (R-corner) enhances the conformity of the guide hole to the rectangular probe (thereby reducing the lateral clearance and movement of the probe within the hole), which in turn achieves higher alignment accuracy.

Eliminating Traditional Pain Points with True Cold Laser Processing

When drilling arrays of thousands of micro-holes into high-density advanced ceramics like Silicon Nitride (Si3N4) and Alumina (Al2O3), traditional CNC or conventional lasers struggle with uneven chamfering, non-vertical walls, and thermal damage that causes micro-cracks.

MONO's femtosecond laser utilizes ultra-short pulses (<1 ps) to bypass the optical diffraction limit. This instantaneous optical cleavage enables true cold machining. Because the interaction time is far shorter than the material's thermal diffusion time, it completely prevents the wall deformation and edge burrs caused by the melting and resolidification of materials. The result is flawless structural integrity with a surface roughness of Ra <0.2μm.

Production-Grade Hard Data: Redefining Micro-Drilling Geometric Precision

MONO's femtosecond laser equipment has already achieved highly stable, mass-production processing for domestic enterprises, drastically reducing the processing cycle per card and boosting the yield rate to 98.5%. Core performance metrics include:

• High Aspect Ratio & Zero Taper: Supports hole diameters from Φ20–100 µm with depths reaching 200–500 µm. In a 500 µm thick Al„Oƒ ceramic substrate case study, we successfully machined Φ50 µm round holes (10:1 aspect ratio) with a front-to-back parallelism of <0.5°, achieving true zero taper (error controlled within ≤±1µm).
• Sub-Micron True Roundness: Utilizing dual-lens CCD and confocal height measurement for precision alignment, combined with multi-pass segmented processing, the micro-hole roundness error is strictly controlled to ≤1µm.
• Ultra-Small R-Corner Control (For Guide Plates): Driven by the evolution of fine pitch probe cards, maintaining the inner corner radius (R-corner) of square holes is critical. Through closed-loop visual inspection, MONO controls the R-corner to <5 µm (with chamfer ≤1 µm) for 50×50 µm square holes. For ultra-high-density MEMS probe cards, we can even push the limits to an R-corner of ≤0.4 µm, preventing large corner radii from encroaching on adjacent hole spaces.

We are committed to leveraging our disruptive energy-control capabilities to provide global customers with the ultimate substrate manufacturing solutions for High-Quality Custom Probe Cards.