Browse Prior Art Database

Method for a thin die, thin TIM package with amorphous metal TIM

IP.com Disclosure Number: IPCOM000008900D
Publication Date: 2002-Jul-22
Document File: 3 page(s) / 87K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a thin die, thin thermal interface material (TIM) package with amorphous metal TIM. Benefits include improved electrical and thermal performance.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 50% of the total text.

Method for a thin die, thin TIM package with amorphous metal TIM

Disclosed is a method for a thin die, thin thermal interface material (TIM) package with amorphous metal TIM. Benefits include improved electrical and thermal performance.

Background

              Die and substrate coefficient of thermal expansion (CTE) mismatch leads to solder ball fatigue, ILD cracking and delamination, and system warpage. No conventional solution to this problem exists.

              To keep the scalability of metal oxide semiconductor field-effect transistor (MOSFET) transistors with a gate length less than 70nm, many new transistors require a biaxially strained channel. Conventionally, the SiGe layer is used to strain the channel of MOSFET transistor. The composition of Ge is limited in many cases. Bigger tensile/compressive strain is required.

General description

      The disclosed method includes the use of a thin, creep resistant amorphous metal layer as the TIM in a package that is comprised of a thin die strongly bonded to a thick copper heat lid. Through controlling the bonding temperature, the biaxial strain in a Si die can be engineered to enhance the carrier mobility, increasing the performance of a variety of transistors.

              When a die is thinned to a relatively small thickness and bonded with a stiff bond to a thick copper heat lid, the die is forced to expand and contract with the lid during thermal cycles. This situation creates a mechanical advantage by eliminating the expansion mismatch between die and package. Problems such as solder ball fatigue and ILD cracking are also eliminated. However, if the material bonding of the die to the lid is able to deform by plastic flow, this advantage may be lost. Using an amorphous metal as the TIM eliminates this problem, as amorphous metals suffer very little time-dependent plastic deformation.

              When the MOSFET channel is under a biaxial strain, the band structure changes and carrier mobility changes. Tensile or compressive strain can be used to enhance the ca...