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Thermally Assisted Micro Via Drilling for Minimized Smear Residue and Improved Via Quality

IP.com Disclosure Number: IPCOM000132641D
Publication Date: 2005-Dec-28
Document File: 3 page(s) / 186K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that controls and manipulates the thermal field residue (in the organic build-up layer) produced by laser irradiation during the drilling process. Benefits include improving the via hole quality and reliability, increasing the efficiency of the laser drilling process.

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Thermally Assisted Micro Via Drilling for Minimized Smear Residue and Improved Via Quality

Disclosed is a method that controls and manipulates the thermal field residue (in the organic build-up layer) produced by laser irradiation during the drilling process. Benefits include improving the via hole quality and reliability, increasing the efficiency of the laser drilling process.

Background

The current laser drilling technique (in combination with a build-up of dielectric materials) leads to the formation of dielectric residue and some silica filler at the via bottom. The residue interferes with de-smear, plating, and via filling, and leads to severe via failures (e.g. via delamination upon thermal stressing) that often affect the product quality and schedule.

Currently, the residue left over after laser drilling is supposed to be removed during the de-smear process. However, the optimization of the de-smear process for roughening and residue removal is often problematic on the HVM level, due to the instability of the chemical bath; the instability is caused by an interruption in the fluid flow and the increased content of silica filler residue. Depending solely on the de-smear process puts via reliability at risk. This risk can be minimized by optimizing the laser drilling process to allow for less residue at the via bottom.

General Description

The disclosed method addresses the heat dissipation problem by engineering for heat loss. Specifically, the disclosed method increases the temperature of the copper capture pad by using an externally applied thermal current. The higher the copper capture pad temperature, the lower the delta temperature be...