Curable Silicone Rubber Composition for Semiconductor Packaging
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Solution Overview
Problem
Silicone rubber compositions face challenges in achieving sufficient bond strength with difficult-to-bond thermoplastic resins like polyphthalamide (PPA) and liquid crystal polymers (LCP) and metal electrodes such as Ag, Au, Ni, and Pd, often leading to separation under rigorous conditions, and discoloration or opacity during intense reactions, which limits their use in semiconductor packaging.
Innovation Solution
A curable silicone rubber composition comprising vinyl-containing organopolysiloxane, organohydrogenpolysiloxane, an aluminum metal-based polymerization catalyst, a platinum group metal catalyst, and a tackifier, which forms a transparent cured product with improved adhesion to these substrates, enhancing the reliability of semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silane coupling agents are added to improve adhesion, then bond strength to substrates is improved, but separation occurs under rigorous conditions because reaction does not proceed to completion
Solution Approach 1:
The patent changes the chemical parameters of the silicone rubber composition by incorporating specific functional groups (epoxy, carboxyl, hydroxyl, or amine groups) that can form strong chemical bonds with substrates. This parameter change enables the composition to achieve complete reaction and stable adhesion under rigorous conditions, resolving the contradiction between initial bond strength and long-term adhesion stability.
Solution Approach 2:
The patent creates a composite material system by combining silicone rubber base polymers with specific functional additives and crosslinking agents. This composite approach allows the material to exhibit both the desired adhesion properties and complete reaction capability, overcoming the limitations of simple silane coupling agents.
2Strength
If intense reaction takes place to improve bond strength, then adhesion is enhanced, but the composition discolors or turns opaque and cannot be used in optical applications
Solution Approach 1:
The patent carefully controls the reaction parameters by selecting specific functional groups and catalysts that enable complete reaction at moderate temperatures. This parameter control allows the composition to achieve strong adhesion while maintaining transparency, making it suitable for optical applications.
Solution Approach 2:
The patent introduces specific functional groups at localized positions within the silicone rubber molecular structure. These localized functional groups provide the necessary reactivity for strong adhesion and complete reaction, while the bulk of the silicone rubber matrix remains transparent and optically clear.
3Stability of the object's composition
If conventional silicone rubber compositions are used, then general rubbery properties are achieved, but separation occurs at the interface between packages and silicone resins under thermal cycling and hot humid storage
Solution Approach 1:
The patent develops a composite silicone rubber material that combines the base silicone rubber polymer with specific functional additives. This composite structure maintains the excellent rubbery properties and weathering resistance of silicone rubber while adding the capability for complete chemical reaction and stable interface adhesion under thermal cycling and hot humid storage conditions.
Solution Approach 2:
The patent modifies the chemical composition parameters of the silicone rubber by incorporating functional groups that can form stable chemical bonds with substrates. This parameter modification enables the material to maintain both its rubbery properties and interface stability under rigorous environmental conditions.
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 composition achieves full adhesion to previously difficult-to-bond substrates, withstands rigorous reliability tests, and maintains transparency, ensuring the semiconductor device's integrity and performance.
Implementation Method 1
an aluminum metal based polymerization catalyst
Implementation Method 2
a platinum group metal based catalyst
Implementation Method 3
a tackifier establishes a sufficient bond strength to substrates
Data Source
AI summary
A curable silicone rubber composition comprising (A) a vinyl-containing organopolysiloxane, (B) an organohydrogenpolysiloxane, (C) an aluminum chelate catalyst, (D) a platinum catalyst, and (E) a tackifier establishes a sufficient bond strength to packaging materials including difficult-to-bond thermoplastic resins such as polyphthalamide resins and liquid crystal polymers and to electrodes of metals such as Ag, Au, Ni and Pd, and forms a transparent cured part. A semiconductor device encapsulated with the cured composition is reliable.