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Method for 3-D surface-mount PCB and package pads

IP.com Disclosure Number: IPCOM000019852D
Publication Date: 2003-Oct-01
Document File: 3 page(s) / 105K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for three-dimensional (3-D) surface-mount printed circuit board (PCB) and package pads. Benefits include improved reliability.

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Method for 3-D surface-mount PCB and package pads

Disclosed is a method for three-dimensional (3-D) surface-mount printed circuit board (PCB) and package pads. Benefits include improved reliability.

Background

Conventional solder joints have 2-D flat copper pads (both on packages and motherboards) that can result in unimpeded fatigue crack growth along the surface of the copper pad in thermal cycling. The mechanical strength of the interface can improve resistance to shock and vibration by increasing the pad area without increasing the footprint. However, improved tensile and shear resistance are required (see Figure- 1).

General description

The disclosed method is a 3-D surface-mount pad for PCBs and ball grid array (BGA) packages. The method improves the thermo-mechanical resistance of the solder joint and improves the solder joint reliability.

         The 3-D pad provides added wettable surface area and improves the mechanical strength of the solder joint. The 3-D nature of the copper pad provides a barrier to crack growth by deflection.

Advantages

         The disclosed method provides advantages, including:

•         Improved reliability due to improved mechanical impedance to the propagation of the fatigue crack by redirection

•         Improved reliability due to improved mechanical strength because of a larger area of joint adhesion

•         Improved reliability due to improved interfacial strength by and increased area of attachment

Detailed description

         The disclosed method adds 3-D structure to a p...