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Structure and method for creating compliant, electromigration-resistant die-substrate interconnects

IP.com Disclosure Number: IPCOM000011843D
Publication Date: 2003-Mar-19
Document File: 3 page(s) / 51K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a structure and method for creating compliant, electromigration-resistant die-substrate interconnects. Benefits include improved performance, improved reliability, and improved ease of manufacturing.

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Structure and method for creating compliant, electromigration-resistant die-substrate interconnects

Disclosed is a structure and method for creating compliant, electromigration-resistant die-substrate interconnects. Benefits include improved performance, improved reliability, and improved ease of manufacturing.

Background

        � � � � � Increasing currents to the die have made the electromigration of the solder typically found in the die-substrate interconnect a concern for meeting future requirements. Decreasing the dielectric constant (K) of on-die dielectrics has resulted in a degradation of mechanical strength to the point where assembly and package stresses often cause structural failure. A die-substrate interconnect solution that simultaneously reduces both electromigration and on-die stress to acceptable levels is required.

        � � � � � The conventional solution is to require the current to the die to be small enough that electromigration damage is minimal. Further, the present strength of the interlayer dielectric (ILD) material is sufficiently high (because the K is relatively high) to enable typical solder bumping to function as an acceptable interconnection, possibly combined with a substrate with a CTE that is better matched to the die’s CTE. However, as current increases and ILD K decreases, this solution is not expected to be sufficient.

        � � � � � High melting temperature intermetallics have a greater resistance to electromigration damage than low melting temperature solders. However, the high melting temperature materials are typically much more resistant to deformation, thereby transferring large stresses to the die, and the temperatures used to process such materials are often incompatible with devices.� All of these factors make their use as a die-substrate interconnect problematic.

General description

        � � � � � The disclosed method is for creating compliant, electromigration-resistant die-substrate interconnects.� These joints are comprised only of high melting temperature materials.

        � � � � � The key elements of the method include:

•        � � � � Compliant interconnects that are used in a series with high melting temperature intermetallics

•        � � � � Intermetallics that are formed at low temperatures over a range of different temperatures

•        � � � � Selection of the stress-free package configuration during assembly

Advantages

� � � � � The disclosed method provides advantages, including:

•        � � � � Improved performance due to...