Circuit Module Contact Element With Zinc Intermediate Layer
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Solution Overview
Problem
Current circuit module manufacturing methods face challenges in using aluminum contact areas due to the brittle contact between copper and aluminum conductors, leading to mechanical stress issues and suboptimal performance, especially in semiconductor processes where aluminum is the most common conductor material.
Innovation Solution
A bumpless circuit module design using contact elements with an intermediate layer of a third metal, such as zinc, between aluminum contact areas and copper conductors, where the contact surface area between the intermediate layer and the contact area is smaller than the total contact area, allowing for improved mechanical durability and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If copper conductors are grown directly on top of aluminium contact areas, then manufacturing simplicity is improved, but mechanical durability deteriorates due to brittle contact between copper and aluminium
Solution Approach 1:
An intermediate layer comprising zinc and aluminium is introduced between the copper conductor and the aluminium contact area. This intermediate layer acts as a mediator that prevents direct contact between copper and aluminium, eliminating the brittle interface while maintaining electrical conductivity and mechanical durability.
2Strength
If sputtering technique is used to grow intermediate metal layer, then adhesion between copper and aluminium is improved, but manufacturing cost increases and conducting density is reduced
Solution Approach 1:
The mechanical sputtering process is replaced with electrochemical growing methods (electroplating or electroless plating). These chemical processes deposit the intermediate layer of zinc and aluminium without requiring vacuum equipment, thereby reducing manufacturing cost and increasing conducting density while achieving comparable or superior adhesion.
3Reliability
If contact element fills entire contact area, then electrical contact quality is maximized, but manufacturing complexity increases
Solution Approach 1:
The contact element is designed with non-uniform distribution: the intermediate layer of zinc and aluminium is concentrated at the contact interface with the aluminium contact area, while the copper conductor extends beyond this region. This local concentration of intermediate material optimizes adhesion where needed without requiring complex manufacturing processes for uniform coverage across the entire contact area.
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 solution enables the use of aluminum contact areas in circuit modules with enhanced mechanical durability and electrical properties, allowing for direct integration of semiconductor circuits without the need for separate packaging, while maintaining compatibility with copper conductors.
Implementation Method 1
an intermediate layer, which contains a third metal, is grown at least on the surface of the contact areas in the contact holes
Implementation Method 2
contact elements for forming electrical contacts between the contact areas and the conductors, which contact elements comprise an intermediate layer
Data Source
AI summary
Manufacturing method and circuit module, which comprises an insulator layer and, inside the insulator layer, at least one component, which comprises contact areas, the material of which contains a first metal. On the surface of the insulator layer are conductors, which comprise at least a first layer and a second layer, in such a way that at least the second layer contains a second metal. The circuit module comprises contact elements between the contact areas and the conductors for forming electrical contacts. The contact elements, for their part, comprise, on the surface of the material of the contact area, an intermediate layer, which contains a third metal, in such a way that the first, second, and third metals are different metals and the contact surface area (ACONT 1), between the intermediate layer and the contact area is less that the surface area (APAD) of the contact area.