Browse Prior Art Database

Method for a split via

IP.com Disclosure Number: IPCOM000020310D
Publication Date: 2003-Nov-12
Document File: 2 page(s) / 64K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a split via. Benefits include improved functionality and improved support for future technology.

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Method for a split via

Disclosed is a method for a split via. Benefits include improved functionality and improved support for future technology.

Background

The interconnect density of resin glass fabric substrate is reaching its limit. As a result, a larger package substrate size is conventionally used.

The conventional method uses a continuous circular pad ring. Each via supports a single trace.

Description

         The disclosed method uses a drilled via to increase the interconnect density capacity of a substrate (see Figure 1).

         The key elements of the method include:

•         Partial pad ring design

•         Cu seed pin to lay an initial Cu seed layer, using electroless plating in specific areas along the via length for the subsequent via plating process

         The disclosed method can be implemented using the following steps:

1. Substitute a partial pad ring for a full-circle pad ring.

2. Drill the via.

3. Use a Cu seed pin to deposit two initial, separate layers of Cu, using electroless plating, along the inside via wall.

4. Plate two parallel traces in each via.

5. Continue with the remaining steps of the process of record.

By splitting each via to support two separate traces, the interconnect density capacity of the substrate is increased.

Advantages

         The disclosed method provides advantages, including:

•         Improved functionality due to increasing the interconnect density capacity of a substrate

•         Improved support for future technology due to improving the functionality

Fig. 1

Disclosed ano...