Intermetallic Compound Substrate Joining for Chip Reliability

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Solution Overview

Problem

Existing methods for joining electronic chips to form complex circuits are costly and limited in versatility due to the need for tailor-made components, and current intermetallic compound connections are prone to mechanical stress-induced failures.

Innovation Solution

A method involving substrates with reception and insertion areas made of different metallic materials, where studs from the insertion area penetrate into the reception area to form separated layers of intermetallic compounds, enhancing mechanical strength and electrical connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an intermetallic compound is formed at the interface between two metallic materials to reduce the distance separating two chips, then the electrical connectivity is improved, but the mechanical strength deteriorates because the intermetallic compound deforms badly plastically and is subject to ruptures under mechanical stresses

Engineering Contradiction:
Improveelectrical connectivityVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent divides the intermetallic compound layer into multiple separated layers instead of forming a single continuous layer. The first intermetallic compound layer is formed between the first metallic material and the second metallic material, while the second intermetallic compound layer is formed between the third metallic material and the second metallic material. These layers are separated by zones of the respective metallic materials, which prevents stress concentration and improves mechanical strength while maintaining electrical connectivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different metallic materials (first, second, and third metallic materials) in different local zones to create specific properties in each region. The second metallic material serves as a common interface material, while the first and third metallic materials are used in specific zones to control the formation of separate intermetallic compound layers, optimizing both electrical and mechanical properties locally.

Inventive Principle:
Principle #3Local quality

2Reliability

If tailor-made chips are produced for a given final circuit to obtain expected synergy between components, then the performance is improved, but the production cost increases significantly

Engineering Contradiction:
Improveperformance synergyVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a universal third metallic material as a base surface that can accommodate multiple different second metallic materials forming studs. This allows the same substrate structure to be used with various chip configurations and metallic material combinations, enabling the assembly of different chip technologies and functions without requiring entirely custom-designed substrates for each application, thereby reducing production costs while maintaining performance synergy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method provides improved mechanical strength and durability by forming intermetallic compounds that resist mechanical stresses and maintain electrical connectivity, while being cost-effective and versatile for various chip configurations.

Implementation Method 1

causing the first metallic material to react with the second metallic material so as to forming a continuous layer of an intermetallic compound based on the first and second metallic materials along the interface between the pads and the reception zone

Methodology Applied
Scientific EffectIntermetallic compound formation: Chemical Bonding

Implementation Method 2

the third th metallic material reacts with the second metallic material to form a second intermetallic compound

Methodology Applied
Scientific EffectIntermetallic compound formation: Chemical Bonding

Data Source

PatentEP2671250B1Method for manufacturing two substrates connected by at least one mechanical and electrically conductive connection and the structure obtained
Publication Date: 2019.06.05 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2671250B1 patent drawingFigure 1~3
  • EP2671250B1 patent drawingFigure 4~7
  • EP2671250B1 patent drawingFigure 8~10

AI summary

A first substrate (2), equipped with an accommodation region (1) made of a first metallic material, is provided. A second substrate (4) equipped with an insertion region (3) comprising a base surface (6) and at least two pads (7) made of a second metallic material is placed facing the first substrate (2). The pads (7) protrude from the base surface (6). Pressure is applied between the first substrate (2) and the second substrate (4) so as to make the pad (7) penetrate into the accommodation region (1). The first metallic material (5) reacts with the second metallic material so as to form a continuous layer of an intermetallic compound (5), based on the first and second metallic materials, along the interface between the pads (7) and the accommodation region (1).