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Method for electrically conductive metal vacuum cups for pick-and-place equipment

IP.com Disclosure Number: IPCOM000010737D
Publication Date: 2003-Jan-15
Document File: 3 page(s) / 112K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for electrically conductive metal vacuum cups for pick-and-place equipment. Benefits include improved functionality and improved reliability.

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Method for electrically conductive metal vacuum cups for pick-and-place equipment

Disclosed is a method for electrically conductive metal vacuum cups for pick-and-place equipment. Benefits include improved functionality and improved reliability.

Background

              Electrostatic discharge (ESD) is a problem for pick-and-place equipment in the semiconductor industry because of the triboelectric charging of the insulating-compliant elastomers used in vacuum cups on electronic packages. The conventional solution is doping the elastomer chemistry with a conductive material, such as carbon black. This method changes the properties of the elastomer from electrically insulating to electrostatic dissipating.

              A conventional elastomer is silicone rubber.

              Pick-and-place equipment conventionally uses rubber vacuum cups. They are sensitive to temperature extremes, which lead to a balancing act between various materials and material interactions. The problem remains unsolved. Material specification for the rubber cups have been repeatedly tightened, but the problem returns because of lot-to-lot and general variations within typical rubber cup manufacturing process. Another solution is bellow-type cup designs.

              Typical rubber cups have a limited life span and must be replaced after a fixed number of cycles.

General description

              The disclosed method is the use of miniature metal vacuum cups in automatic pick-and-place machinery. The metal cups provide a ground path to the equipment tooling/frame and the chassis ground. Mechanical alignment chucks use one or more vacuum pick-up cups to touch down on the package substrate and provide vacuum coupling for pick up.

 

              The key elements of the method include:

•             Threaded cylindrical metal base to mount into a metal tooling alignment chuck

•             Metal cup touch-down surface for metal pick up

•             Miniature conductive compr...