Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Method for a diffusion barrier for copper metallization of semiconductor packages

IP.com Disclosure Number: IPCOM000033137D
Publication Date: 2004-Nov-29
Document File: 4 page(s) / 83K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a diffusion barrier for copper metallization of semiconductor packages. Benefits include improved functionality, improved performance, improved ease of manufacturing, and improved ease of implementation.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 41% of the total text.

Method for a diffusion barrier for copper metallization of semiconductor packages

Disclosed is a method for a diffusion barrier for copper metallization of semiconductor packages. Benefits include improved functionality, improved performance, improved ease of manufacturing, and improved ease of implementation.

Background

      The conventional semiconductor package includes a core material with copper traces and solder resist which is a polymer based material (see Figure 1). Unfortunately, copper forms a weak chemical bond with polymer and diffuses into it to form agglomerates. This chemical reaction decreases the effective separation between copper lines. When two adjacent copper wires are at different potentials, an intense electric field forms in the dielectric because the separation of the copper wires is in the submicron range. The electric field strength can easily damage the dielectric and result in electrical shorting, especially when the semiconductor package is subjected to high temperature and humidity.

              Conventionally, no solution exists to resolve the copper migration problem in high and low density interconnect semiconductor packages. A possible solution is the introduction of impurities in the copper, which would reduce the conductivity of the interconnect material.                                                                                               

The prevention of copper migration becomes increasingly important as copper lines become closer in the future.

      The distance between adjacent copper lines is limited due to copper migration across the dielectric when the unit is subjected to high temperature, moisture and electric field conditions during reliability testing. The degree of copper migration is highly dependent on the properties of the dielectric material. Typical copper migration levels range from 5-7 microns.  The proximity restrictions can be overcome to allow tighter design rules by the introduction of diffusion barrier.

      General description

      The disclosed method is a coating of a metallic thin film that serves as a diffusion barrier for copper metallization of high and low density interconnect semiconductor packages.  The method uses a metallic thin-film coating on the surface of copper metallization in semiconductor packages. The metallic thin film encapsulates the copper. The thin film is deposited via an electroless process and can be composed of any one of the following alloy systems or pure metals: Co(P), CoWP, Ni-Co(P), Ni(P),Co(P), Co, Ni. Electroless deposition is a conventional technique for forming interconnect structures on semiconductor packages.

Advantages

              The disclosed method provides advantages, including:

•             Improved functionality due to preventing the migration of copper atoms across dielectric due to the presence of a diffusion...