Laser apparatus having improved via processing rate
US5973290A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 26, 1997 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Feb 26, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/486
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A laser via drilling system, and method of operation thereof, operates at an increased pulse repetition rate, but provides output pulses of sufficient energy and consistent pulse to pulse energy. In order to drill a via hole in a substrate, a pulsed laser beam is formed using a lithium triborate (LiB.sub.3 O.sub.5) crystal for harmonic generation. The laser beam has an energy density that is greater than an ablation threshold of the substrate. A via hole is formed using the pulsed laser beam. The energy density of the pulsed laser beam is decreased to an energy density that is less than the first energy density and is less than the ablation threshold of the substrate. The pulsed laser beam is re-positioned to a site of a next via to be formed. The energy density of the pulsed laser beam is increased back to the original energy density and a next via hole is formed. The energy density of the pulsed laser beam is decreased by increasing the pulse repetition rate of the beam. Likewise, the energy density of the pulsed laser beam is increased by decreasing the pulse repetition rate of the beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.