Addition-Curable Silicone Resin for LED Die Attach
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Solution Overview
Problem
Conventional addition-curable silicone resin compositions used as die attach materials for optical semiconductor devices often result in contamination of gold electrode pads due to low-molecular-weight siloxanes, which affects wire bondability, and existing methods to reduce contamination are time-consuming and costly.
Innovation Solution
An addition-curable silicone resin composition comprising a linear organopolysiloxane, a branched organopolysiloxane, and an organohydrogenpolysiloxane with specific compositional formulas and molecular weight ranges, along with a catalyst, to minimize contamination and enhance wire bondability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If addition-curable silicone resin composition is used as die attach material, then heat resistance and light resistance are improved, but contaminant deposition on electrode pads occurs due to low-molecular-weight siloxanes
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight distribution and chemical composition of the silicone resin. Specifically, it uses organopolysiloxanes with vinyl groups at both ends having a viscosity of 10-1000 Pa·s and organohydrogenpolysiloxanes with a viscosity of 10-10000 Pa·s, optimizing the balance between heat resistance, light resistance, and contaminant reduction without requiring complex removal processes
Solution Approach 2:
The patent employs composite materials by formulating a multi-component resin system comprising vinyl-terminated organopolysiloxane, organohydrogenpolysiloxane, and catalytic components. This composite approach achieves high reliability with heat and light resistance while minimizing low-molecular-weight siloxane contamination through the synergistic interaction of different polymer components
2Object-generated harmful factors
If low-molecular-weight siloxane content is reduced to decrease contaminant deposition, then wire bondability is improved, but resin strength and curing performance may be compromised
Solution Approach 1:
The patent optimizes the viscosity parameters of the polymer components to achieve the desired balance. By specifying vinyl-terminated organopolysiloxane with viscosity of 10-1000 Pa·s and organohydrogenpolysiloxane with viscosity of 10-10000 Pa·s, the formulation maintains adequate low-molecular-weight content for strong curing while limiting excessive contamination that would harm wire bondability
3Object-generated harmful factors
If thin-film distillation unit is used to remove low-molecular-weight siloxanes, then contaminant deposition is reduced, but processing time and cost increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-optimizing the resin composition during manufacturing to inherently minimize low-molecular-weight siloxane content. The selected polymer components with controlled viscosity ranges are formulated to reduce contaminant generation at the source, eliminating the need for subsequent time-consuming distillation or removal operations
Solution Approach 2:
The patent takes out the problematic low-molecular-weight siloxane components by carefully selecting polymer molecular weights and viscosities that prevent excessive low-MW species formation. This extraction approach is achieved through intelligent material selection rather than post-processing removal methods
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 effectively reduces contamination of gold electrode pads and improves wire bondability, providing a high-strength cured product suitable for optical semiconductor devices without the need for extensive low-molecular-weight siloxane removal operations.
Implementation Method 1
addition-curable silicone resin composition which includes: (A-1) a linear organopolysiloxane having at least two alkenyl groups per molecule; (A-2) a branched organopolysiloxane... (B) an organohydrogenpolysiloxane... (C) a catalyst
Implementation Method 2
with the application of heat during the cure, low-molecular-weight siloxanes having silicon atom-bonded hydrogen atoms (SiH groups) thereon vaporize, forming a film on the electrode pads due to hydrolysis reactions
Implementation Method 3
forming a film on the electrode pads due to hydrolysis reactions
Data Source
AI summary
An addition-curable silicone resin composition includes (A-1) a linear organopolysiloxane having at least two alkenyl groups per molecule, (A-2) a terminal alkenyl group-containing branched organopolysiloxane having at least two alkenyl groups per molecule, (B) an organohydrogenpolysiloxane with a content of low-molecular-weight siloxane having a degree of polymerization of up to 10 and one or more terminal SiH group per molecule of 5 wt % or less, and (C) an addition reaction catalyst. The composition can be cured to form a product which, when used as a die attach material for optical semiconductor devices, minimizes contamination of the gold electrode pads on LED chips and imparts a good wire bondability.