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Method for an anchor-reinforced metal pad

IP.com Disclosure Number: IPCOM000130483D
Publication Date: 2005-Oct-25
Document File: 2 page(s) / 652K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an anchor-reinforced metal pad. Benefits include improved functionality and improved performance.

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Method for an anchor-reinforced metal pad

Disclosed is a method for an anchor-reinforced metal pad. Benefits include improved functionality and improved performance.

 

Background

      Metal defined (MD) and soldermask defined (SMD) pads are conventionally used as flat pads with uniform diameters for second-level interconnections (SLIs). MD pads are typically smaller than SMD pads and are more subject to thermomechanical stress and cracking (see Figure 1).                                                                                   

      In conventional SMD pads, the contact of the solder mask with the solder ball and the coplanarity of the solder/metal pad interface causes failures from thermomechanical stress. Typical MD pads do not have this weakness because the solder contacts the metal pad on more than one plane, inhibiting the propagation of fractures along the solder/metal interfaces. However, because an MD pad must be smaller than an SMD pad with an equivalent solderable area, the area of metal pad adhered to the FR-4 epoxy resin/woven glass cloth material must decrease. The decreased contact can contribute to failure from mechanical stress.

Description

              The disclosed method is a metal pad on a package or PCB designed to strengthen the electromechanical connection between the PCB and the electronic package or interposer (the SLI). The center contains an elevated area (ancho...