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Anti-Static Package for Electro Discharge

IP.com Disclosure Number: IPCOM000248202D
Publication Date: 2016-Nov-09
Document File: 4 page(s) / 317K

Publishing Venue

The IP.com Prior Art Database

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This is the abbreviated version, containing approximately 45% of the total text.

Page 01 of 4

Anti-Static Package for Electro Discharge

Background

The problem with semiconductor packaging of the affects of electrostatic discharge (ESD) has become increasingly acute since smaller profiles are expected in the integrated circuits. The build-up of electrostatic charges on the packages will result in a spark and thus destroy the semiconductor chips, printed circuits or other electronic units. In a similar way, ultra pure chemicals or drugs in electronic or medical industries have strict restrictions on the amount of foreign particulates present. It causes severe contamination for packaging the chemicals or drugs because an electrostatic charged surface will attract charged particulates in air. Therefore, the prevention and control of static charge build-up on the packages is a major goal in a wide range of industry, from aero space and electronics to medical and drug.

Several anti-static packages and packaging materials are proposed to prevent and minimize static build-up. In one method, a plastic film or sheet is compounded with anti-static additives such as quaternary amines, amine salts or soaps. A major drawback for the method is that the design does not provide shielding from external static fields. In another method, grounding electrostatic charges brought into contact with the envelope or packages is described in U.S. Pat. No. 4,154,344 and No. 4,156,751. The patents teach a design in which a flexible substrate is coated on one side with an anti-static polyethylene material and on the other side with a very thin layer of nickel. The anti-static layer defines the interior of the package and the metal layer is on the exterior of the package. Electrostatic charge will not build up due to the metal layer. However, the optical transmission of the nickel layer in the visual spectrum is not good enough for visual inspection. Furthermore, particulates are likely to flake off from the nickel layer and may contaminate the clean room. In addition, when electronic components are taken out of the package for testing and when are replaced, the external metal layer provides a conductive path and a body contact with an electric terminal may provide a source of electrical shock to the testing personnel.

In U.S. Pat. No. 4,424,900, an anti-static package composed of a multiply flexible film is shown in Fig.1. The inner ply is an anti-static material and the outer ply is an electrically insulating material. A conductive metallic ply is sandwiched between the inner and outer ply. The conductive material is sputtered onto one of the two plies and the other ply is bond by an adhesive bond to the metal ply.

Fig. 1 The anti-static package disclosed in U.S. Pat. No. 4,424,900


Page 02 of 4

Anti-Static Package for Electro Discharge

However, the electrostatic discharge (ESD) is still a severe issue. First, die surface is suffered of high voltage during detaching film in the electro discharge mold process; and second, die surface is suffered of fri...