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Improving the Adhesion of Plated Metal to Dielectric Materials

IP.com Disclosure Number: IPCOM000130521D
Publication Date: 2005-Oct-25
Document File: 2 page(s) / 42K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that sputters conducting seed layers on dielectric materials prior to the plating process. Benefits include eliminating the need for the chemical and/or mechanical roughening of dielectric surfaces.

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Improving the Adhesion of Plated Metal to Dielectric Materials

Disclosed is a method that sputters conducting seed layers on dielectric materials prior to the plating process. Benefits include eliminating the need for the chemical and/or mechanical roughening of dielectric surfaces.

Background

The following are current issues with the process:

§         The adhesion of finely defined metallic lines to various dielectrics, including polymers used in package substrates (e.g. epoxies and thermo-set polyimides). Roughening the dielectric surface allows the seed layer to penetrate deeper, and create “anchor” points for atoms deposited from the electro-plating bath.

§         Dielectric roughening steps, either mechanical or chemical, are used to ensure the adhesion of plated lines. This causes serious variations in the expected results. Roughening the insulator surface with chromic acid mixes enables a deeper penetration of atoms in the subsequent sputtering process. This process is environmentally unfriendly because it generates massive volumes of waste water that must be treated for Cr ions.

§         Sputtering small atoms like Cr or Ti leads to electrical shortings between fine lines and spaces. Another approach deep sputters Cr atoms to create openings in the dielectric, and then chemically etches Cr after plating. This technique creates short-circuits because deeply sputtered Cr is not accessible to etch solutions, and therefore may conduct electrical currents.

General Description

The discl...