Bimetallic Contact Element for Reliable Chip Packaging
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Solution Overview
Problem
Current packaging technologies face challenges in manufacturing electronic chips in a simple and reliable manner, particularly in establishing robust and efficient electrical connections without damaging the semiconductor chip, and in avoiding material bridges between different metallic materials.
Innovation Solution
A bimetallic or multimetallic contact element is used, comprising a first contact structure made of one electrically conductive material and a second contact structure made of another material, which extends through the encapsulant to provide a stable and robust electrical connection, allowing for easier wire bonding and reduced mechanical stress on the chip during packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-material contact element is used, then the manufacturing process is simple, but the mechanical connection stability and wire bonding ease are compromised
Solution Approach 1:
The contact element is constructed as a composite structure with a first contact structure made of a first electrically conductive material and a second contact structure made of a second electrically conductive material. This composite material approach allows each material to be optimized for its specific function: one material for stable mechanical connection to the chip pad and another for ease of wire bonding, thereby resolving the contradiction between connection stability and bonding ease without increasing overall device complexity.
Solution Approach 2:
Different portions of the contact element are made from different materials with properties optimized for their local functions. The first contact structure uses material suitable for chip pad attachment, while the second contact structure uses material optimized for wire bonding. This local differentiation of material properties enables each section to perform its specific function optimally, improving overall reliability without requiring a completely complex multi-component structure.
2Ease of operation
If different metallic materials are used in the contact element, then wire bonding is easier and mechanical stress is reduced, but material bridges may form between different metals
Solution Approach 1:
The patent employs an encapsulant material that acts as an intermediary barrier between the first and second electrically conductive materials. The encapsulant at least partially surrounds the contact element, physically separating the two different metals and preventing direct contact that would lead to material bridge formation. This allows the system to utilize the benefits of different materials for wire bonding ease while the encapsulant mediates and prevents the harmful interaction between dissimilar metals.
3Reliability
If the contact element extends through the encapsulant, then electrical connection is more robust, but the risk of chip damage during packaging increases
Solution Approach 1:
The contact element is pre-formed with its bimetallic structure before the encapsulation process. The first contact structure is already attached to the chip pad, and the second contact structure is prepared for wire bonding. This preliminary preparation allows the encapsulant to be applied without requiring subsequent manipulation that could damage the chip, as the robust electrical connection is already established before the chip is enclosed in the encapsulant.
Data Source
AI summary
A package and method of making a package is disclosed. In one example, the package includes an electronic chip having at least one pad, an encapsulant at least partially encapsulating the electronic chip, and an electrically conductive contact element extending from the at least one pad and through the encapsulant so as to be exposed with respect to the encapsulant. The electrically conductive contact element comprises a first contact structure made of a first electrically conductive material on the at least one pad and comprises a second contact structure made of a second electrically conductive material and being exposed with respect to the encapsulant. At least one of the at least one pad has at least a surface portion which comprises or is made of the first electrically conductive material.