Smart Card Module Flip-Chip Mounting Thickness Reduction
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Solution Overview
Problem
Existing smart card modules face challenges in achieving a balance between thinness, robustness, and cost-effectiveness due to structural limitations and susceptibility to mechanical loading, particularly with flip-chip mounting and adhesive bonding methods.
Innovation Solution
A smart card module design featuring a semiconductor chip with contact-side connections to a metal layer, encapsulated by a plastic and metal layer combination, which provides flexibility and robustness while maintaining a thin thickness of less than 120 μm, using a resin-coated copper foil or prepreg for enhanced stability and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonds are used to connect the chip, then electrical connection is achieved, but the module thickness increases
Solution Approach 1:
The invention removes the wire bonds and their associated bonding pads from the system. Instead, the chip is directly connected to the substrate through contact pads on the chip's active surface, eliminating the need for wire bonds and thereby reducing module thickness while maintaining electrical connection reliability
Solution Approach 2:
Instead of connecting the chip to the substrate through wire bonds from the chip's back surface, the invention inverts the approach by making direct contact connections from the chip's active surface downward to the substrate, achieving electrical connection without increasing thickness
2Length of stationary object
If flip-chip mounting is used, then module thickness is reduced, but mechanical robustness decreases
Solution Approach 1:
The invention uses a composite structure combining the chip, substrate with metal layers, and encapsulating layer. This composite design provides both thinness (through direct chip-to-substrate connection) and mechanical robustness (through the combined structural integrity of all layers working together)
Solution Approach 2:
The invention applies different material properties to different regions: the chip and substrate provide structural support, the metal layers provide electrical connection and additional mechanical strength, and the encapsulating layer provides protection and environmental sealing. This localized optimization achieves both thinness and robustness
3Strength
If adhesive bonding is used, then mechanical stabilization is achieved, but module thickness increases and delamination risk occurs
Solution Approach 1:
The invention removes the adhesive layer from the system entirely. Instead of using adhesive bonding between the chip and substrate, direct electrical and mechanical contact is established through the contact pads on the chip's active surface, eliminating both the thickness increase and delamination risk associated with adhesives
Solution Approach 2:
The metal layers on the substrate serve as an intermediary structure that provides both electrical connection and mechanical support, replacing the function previously performed by adhesive bonding while avoiding its drawbacks of increased thickness and delamination
Data Source
AI summary
A smart card module and a method for producing a smart card module are provided. The smart card module comprises a semiconductor chip having a contact side with a plurality of contacts, and a base material with at least one metal layer. The contact side of the semiconductor chip faces the base material and the plurality of contacts of the semiconductor chip are electrically connected to the metal layer. The semiconductor chip and at least a portion of the base material are covered with an encapsulation layer.