Overview of LPKF TGV ProcessBase material is an industrial standard glass for interposers.
Additional Process Steps for Interposer Production
Variable ProcessesGlass interposers are mainly manufactured using two processes, both of which can be implemented with the LPKF TGV technology. Thus, the TGV process can be smoothly integrated into existing production chains. In the wafer-based process, blind holes are first produced in the glass. Then the wafer is polished down to the desired glass thickness. This creates conical through-glass vias with constant taper angles and aspect ratios (hole diameter to glass thickness) of up to 1:10. The panel-based process generates classic vias, usually in thin substrates. The glass is processed over the entire thickness by laser modification. Subsequent etching is performed uniformly on both sides to produce the desired hourglass shape. Here, too, aspect ratios of up to 1:10 can be achieved.
The laser and etching steps generate conical blind vias in the glass. Subsequent polishing opens the holes of the bottom side.
The vias exhibit pinched waists. The top diameter adjusts itself in relation to the extent of material reduction.
Variable Hole GeometriesBoth processes can be used for glass with a thickness of up to 300 μm. Hole diameter is primarily a function of the etching time. Currently holes with diameters down to 5 μm can be made in 50-micron-thick glass in mass production operations. Through control of the etching duration, the hole diameter can be adjusted precisely. The etching process reduces the overall thickness of the glass wafer by approximately 20 %.
- Glass as interposer
- Efficient ultrafast laser process
- More than 5 000 holes per second
- Panel or wafer format
LPKF Process for High-Speed TGV Formation