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Cold Ablation Using a Pico-Second Laser for iTFC Patterning and Via Drilling

IP.com Disclosure Number: IPCOM000132640D
Publication Date: 2005-Dec-28
Document File: 2 page(s) / 56K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses an ultra-short pulse laser to drill micro-vias in the iTFC structure. Benefits include minimizing heat induced damages and eliminating the need for wet etching.

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Cold Ablation Using a Pico-Second Laser for iTFC Patterning and Via Drilling

Disclosed is a method that uses an ultra-short pulse laser to drill micro-vias in the iTFC structure. Benefits include minimizing heat induced damages and eliminating the need for wet etching.

Background

The current iTFC design requires the formation of intricate and complex via arrays that go through a different stack-up of materials, including: organic build up (i.e. ABF), copper, and BST (i.e. ceramic materials). These different iTFC stack-up materials makes it difficult to define a laser source that can drill through without creating damage such as; causing heat-affected zone formations, cracking the BST film, or melting the copper. Preliminarily evaluations at substrate suppliers indicate that long wavelength, wide-pulse lasers are not suitable to process the iTFC structure. This is because they introduce appreciable amounts of thermal energy into the iTFC structure during the laser pulse-on time. Due to the differences in the thermo-physical properties of the different materials, heat build up, cracking, melting, and delimitation are direct results of long-pulse laser irradiation.

General Description

The disclosed method uses an ultra-short pulse laser that minimizes the damage to the iTFC structure, and delivers the required alignment and dimensional accuracy to drill the micro-via structures (see Figure 1). Laser pulses with pulse durations in the pico-second range are an effective solution. Robu...