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Method for thermally conductive fillers for semiconductor packaging materials with low electrical conductivity

IP.com Disclosure Number: IPCOM000011737D
Publication Date: 2003-Mar-12
Document File: 3 page(s) / 72K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for thermally conductive fillers for semiconductor packaging materials with low electrical conductivity. Benefits include improved thermal performance, improved performance, and improved design flexibility.

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Method for thermally conductive fillers for semiconductor packaging materials with low electrical conductivity

Disclosed is a method for thermally conductive fillers for semiconductor packaging materials with low electrical conductivity. Benefits include improved thermal performance, improved performance, and improved design flexibility.

Background

              Due to increasing power and processing speeds, thermal management is a major concern for processors and a growing concern for non-processors. Heat must be removed from the active side of the die without interfering with the electrical function of the die. For non-processors and stacked die packages, thermally conductive mold compounds and die attach materials with low electrical conductivity are required. For processors, thermally conductive underfill materials may be used for additional heat removal.

              Conventional materials used on the active side of the die include:

•             Molding compounds

•             Die attach adhesives

•             Overmold underfills

•             Underfills

              These materials have a very low thermal conductivity of less than ~1 W/mK. Using ceramic fillers, such as BN and Al2O3, which have bulk thermal conductivities of ~80-100 W/mK, the thermal conductivities of the materials could be increased up to ~2 W/mK. The use of metal fillers (such as Ag and Al) have bulk thermal conductivities of ~490 and 230 W/mK, respectively, could provide very high thermal conductivity but also make the material electrically conductive. As a result, they cannot be used in applications that contact the active side of the die or exposed wires. For example, Ag-filled die attach materials are well known but can only be used to attach the inactive side of the die to a substrate. They cannot be used for stacked dies in which the active side of one die is bonded to another die.

General description

      The disclosed method is thermally conductive fillers for semiconductor packaging materials with low electrical conductivity. Semiconductor packaging materials require high thermal conductivity and low electrical conductivity. Fillers remove heat from the active side of the die.

              The key elements of the method include:

•             Filler with a metal core (such as Ag and Al) for high thermal conductivity and an outer shell of metal oxide (such as Ag2O and Al2O3) for electrical insulation

•             Fillers that are comprised of the following:

-         Molding compound

-         Adhesive formulations (such as die-attach adhesives)

-         Underfill materials

-         Overmold/underfill materials

•             Electronic packages that are comprised of a silicon die and a package with one or more filler materials

Advantages

              The disclosed method provides advantages, including:

•             Improved thermal performance due to the fillers removing heat from the active side of the die

•             Improved performance due to the optimization of the filler formulation for the matrix material...