Chip Module Encapsulation Using Dual-Polymer Chemical Resistance
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Solution Overview
Problem
Conventional encapsulation materials for smart cards are inadequate in protecting semiconductor chips against various chemical attacks, as they can be easily removed by wet-chemical attacks, and materials like glass or ceramics are not suitable due to high processing temperatures and thermal expansion issues, leading to chip damage.
Innovation Solution
A thermosetting polymer composition with multiple polymer components, each providing resistance to different classes of chemical attacks, combined with a filler material like quartz or fluorocarbons, forms a virtually universal wet-chemical resistant encapsulation that can only be removed layer by layer with great difficulty, preventing chip damage during attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encapsulation materials are used, then the chip is protected against mechanical loading, but the encapsulation can be easily removed by wet-chemical attacks
Solution Approach 1:
The patent applies composite materials by combining multiple polymer components (at least two different polymer types) into a single encapsulation material. Each polymer component provides resistance to different classes of chemical attacks, creating a composite structure that offers broader chemical resistance than individual materials. This directly resolves the contradiction by maintaining mechanical protection while adding resistance to wet-chemical attacks through the synergistic combination of materials.
Solution Approach 2:
The patent changes the chemical composition parameters of the encapsulation material by specifying particular polymer types with distinct chemical resistance profiles. By selecting polymers resistant to different classes of chemicals (e.g., acid-resistant vs. base-resistant polymers), the material's chemical resistance parameters are optimized to withstand various wet-chemical attack scenarios while maintaining its mechanical protective function.
2Reliability
If glass or ceramic materials are used for encapsulation, then chemical resistance is improved, but chip damage occurs due to high processing temperatures and thermal expansion
Solution Approach 1:
The patent changes the processing temperature parameter by using polymer-based encapsulation materials that can be cured at low temperatures (typically below 150°C), unlike glass or ceramics requiring high-temperature processing. This temperature parameter change prevents thermal damage to the chip while achieving the desired chemical resistance through the polymer's molecular structure and crosslinking.
Solution Approach 2:
The patent applies local quality by selecting polymer materials with specific local properties tailored to different aspects of chip protection. The polymer composition can be locally optimized to provide chemical resistance at the chip surface while maintaining flexibility and thermal compatibility throughout the encapsulation body, avoiding the uniform high-temperature processing required by glass or ceramic materials.
3Reliability
If glass or ceramic encapsulation is used, then chemical resistance is improved, but adhesion to chip is insufficient allowing mechanical removal
Solution Approach 1:
The patent changes the adhesion parameter by using polymer materials that can form strong chemical and physical bonds with chip surfaces at low processing temperatures. The polymer's functional groups and curing mechanisms enable strong interfacial adhesion, preventing the encapsulation from being mechanically removed while maintaining chemical resistance throughout the material structure.
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 encapsulation material effectively protects smart card chips from wet-chemical attacks, making it extremely difficult to decompose without damaging the chip, thus enhancing security against data manipulation and unauthorized access.
Implementation Method 1
the first polymer component imparting resistance toward a first class of chemically reactive compounds and the second polymer component imparting resistance toward a second class of chemically reactive compounds
Implementation Method 2
a polymer composition having at least a first polymer component and a second polymer component which are chemically covalently bonded by means of a crosslinker
Data Source
AI summary
A chip module with a substrate having a top side, a chip mounted on the top side of the substrate, and an encapsulation includes an encapsulation material. The encapsulation is applied on the chip and the top side of the substrate in such a way that the chip and the top side of the substrate are at least partly covered. The encapsulation material includes a polymer composition having at least a first polymer component and a second polymer component which are chemically covalently bonded by means of a crosslinker, the first polymer component imparting resistance toward a first class of chemically reactive compounds and the second polymer component imparting resistance toward a second class of chemically reactive compounds, the reactivities differing between the first and second classes of chemically reactive compounds.