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Modified Polyimide for Low End Packaging

IP.com Disclosure Number: IPCOM000040808D
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+3]

Abstract

Polyimides are useful in packaging applications where multilayer structures are utilized. For example, polyimide is an electrically insulating layer between multiple layers of metallurgy. While polyimide is suitable for an intermediate layer in a structure, its low thermal conductivity makes it unsuitable as a top layer where it is subjected to heat when chips are softer bonded to the structure. In order to increase the thermal conductivity of polyimide without sacrificing its insulating properties, a particulate filler having a higher thermal conductivity and a lower electrical conductivity is incorporated into the polyimide. An example is boron nitride (BN).

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Modified Polyimide for Low End Packaging

Polyimides are useful in packaging applications where multilayer structures are utilized. For example, polyimide is an electrically insulating layer between multiple layers of metallurgy. While polyimide is suitable for an intermediate layer in a structure, its low thermal conductivity makes it unsuitable as a top layer where it is subjected to heat when chips are softer bonded to the structure. In order to increase the thermal conductivity of polyimide without sacrificing its insulating properties, a particulate filler having a higher thermal conductivity and a lower electrical conductivity is incorporated into the polyimide. An example is boron nitride (BN).

As a precursor, BTDA-ODA polyamic acid can be "loaded" with suspended inorganic particles without the use of surfactants.

The BTDA-ODA polyimide is prepared and loaded with particles of an inorganic powder, such as the following suspensions: iron oxide, carbon, aluminum oxide, silica, and boron nitride. If the particles to be loaded into the polyamic acid are conductors, then the organic solid content is on the order of 10 to 15%, producing an intermediate molecular weight product. In the case of insulators, then the solid content is increased to approximately 20 to 25%, to produce a high molecular weight product. This process appears to be a function of the pH of the particles with respect to the ODA. The loaded solution is then spin-coated onto a substrate and cure...