Smart Card Contact Pad with Organometallic Corrosion Protection
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Solution Overview
Problem
The high manufacturing cost and environmental impact of using precious metals like gold on both sides of smart card contact pads, along with the challenge of preventing oxidation of non-noble metal flip-chip terminal connection layers, are not effectively addressed by existing technologies.
Innovation Solution
A smart card contact pad design featuring a flexible imageable circuit substrate with a noble metal card-reader contact element and a non-noble metal chip terminal connection element, where an organometallic electrically-conductive corrosion-protection layer is applied to the non-noble metal chip terminal connection surface to prevent oxidation, and a roll-to-roll manufacturing process is used to reduce costs and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold is used on both sides of the smart card contact pad, then corrosion and oxidation resistance is improved, but manufacturing cost increases and precious metal depletion accelerates
Solution Approach 1:
The patent applies different metal layers to different sides of the contact pad: gold is used only on the card-reader contact side where corrosion resistance is critical, while the chip mounting side uses a non-noble metal layer (such as copper or aluminum) that is less expensive and does not require the same level of corrosion protection, thus reducing overall precious metal usage while maintaining necessary reliability
Solution Approach 2:
The patent employs composite material structures with multiple layers including non-noble metal layers, noble metal layers, and organic corrosion protection layers. This composite approach allows the contact pad to achieve the required corrosion and oxidation resistance through the combination of materials rather than relying solely on expensive gold on both sides, thereby reducing manufacturing cost while maintaining reliability
2Ease of manufacture
If non-noble metal is used for chip terminal connection layer, then manufacturing cost decreases, but oxidation resistance deteriorates
Solution Approach 1:
The patent introduces an organic corrosion protection layer as an intermediary between the non-noble metal chip terminal connection layer and the environment. This protective layer acts as a barrier that prevents oxidation and corrosion of the non-noble metal, allowing the use of cost-effective non-noble metals while maintaining the required oxidation resistance for reliable operation
Solution Approach 2:
The contact pad uses a composite structure where a non-noble metal layer (such as copper or aluminum) is combined with an organic corrosion protection layer. This composite material system provides both the electrical conductivity and cost benefits of non-noble metals while the organic layer supplies the necessary oxidation protection, resolving the contradiction between manufacturing cost and reliability
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
This design reduces the use of noble metals, prevents oxidation of non-noble metal chip terminal connections, and lowers manufacturing costs while maintaining electrical conductivity and aesthetic appeal, thereby addressing the environmental concerns and cost issues associated with traditional smart card contact pads.
Implementation Method 1
applying an organometallic electrically-conductive corrosion-protection layer to the whole of a non-noble metal chip terminal connection surface prior to mounting of an IC chip
Data Source
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AI summary
A contact smart card (100, 101) comprises a smart card contact pad (10) and an IC chip (200, 300). The smart card contact pad 10 includes an imageable circuit substrate (12), a card-reader contact element (14) on a first side (16) of the imageable circuit substrate (12), and a, preferably flip-chip, connection element (18) on a second side (20) of the imageable circuit substrate (12) which is opposite the first side (16). The card-reader contact element (14) has a noble metal electrically conductive surface (30), and the connection element (18) has a chip terminal connection surface (36) which is not a noble metal. The IC chip (200, 300) is preferably flip-chip mounted at the second side (20) of the imageable circuit substrate (12) and electrically connected to the chip terminal connection surface (36). Furthermore, the chip terminal connection surface is preferably an organometallic electrically conductive corrosion protection layer.