Capillary Underfill Adhesive System for Semiconductor Reliability
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Solution Overview
Problem
Traditional capillary underfill resins for semiconductor chips face challenges with high thermal expansion coefficients, low filler loadings, and processability issues, limiting their effectiveness in filling air gaps and improving solder bump fatigue life.
Innovation Solution
A solvent-free adhesive system incorporating a compatibilized and passivated refractory solid dispersed in a low-temperature liquid curing agent, combined with a curable epoxy resin, which allows for higher filler loadings and improved thermal expansion matching with semiconductor chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If filler loading is increased to match CTE of semiconductor chip, then coefficient of thermal expansion is improved, but processability deteriorates
Solution Approach 1:
The patent changes the physical state parameter of the curing agent from solid to liquid at room temperature, and adjusts the filler particle size parameter to nano-scale. These parameter changes enable the system to achieve high filler loading (above 30 wt%) with improved processability, as the liquid curing agent provides better流动性 and the nano-fillers have smaller aggregate sizes that reduce viscosity increase.
Solution Approach 2:
The patent creates a composite adhesive system combining epoxy resin with refractory solid fillers (such as alumina, silica, or titania) and a liquid curing agent. This composite structure allows the fillers to be uniformly dispersed at high concentrations while the liquid curing agent ensures proper flow and bonding characteristics, resolving the contradiction between high filler content and processability.
2Reliability
If filler loading is increased above 30 weight percent, then coefficient of thermal expansion matches semiconductor chip, but viscosity increases and processability decreases
Solution Approach 1:
The patent utilizes parameter changes in the curing agent (liquid state at room temperature) and filler characteristics (nano-scale dimensions) to decouple the relationship between filler loading and glass transition temperature. The liquid curing agent system allows high filler content without proportionally increasing Tg, as the liquid phase provides free volume that maintains molecular mobility despite high filler concentration.
3Reliability
If traditional solid curing agent is used, then curing reaction occurs, but dispersion of refractory solid is poor and processability is limited
Solution Approach 1:
The patent fundamentally changes the physical state parameter of the curing agent from solid to liquid at room temperature. This parameter change dramatically improves the dispersion quality of refractory solids, as the liquid curing agent can readily wet and separate filler particles, preventing aggregation and enabling uniform distribution throughout the adhesive system.
Solution Approach 2:
The liquid curing agent acts as an intermediary medium between the epoxy resin and refractory fillers. It facilitates proper wetting of filler surfaces and enables uniform dispersion by reducing interfacial tension and improving流动性, while still maintaining the ability to cure the epoxy resin effectively.
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 solution achieves a coefficient of thermal expansion below 50 ppm/°C, enables filler loadings greater than 30 weight percent, and maintains processability, transparency, and high glass transition temperatures, enhancing the reliability and durability of electronic devices.
Implementation Method 1
a compatiblized and passivated refectory solid dispersed within a hardener or a curing agent, which are liquid at low temperature
Implementation Method 2
after the addition of a curing agent, the final filler loading may be below 30 weight percent of the total composition
Data Source
AI summary
A cure system including a compatiblized and passivated refectory solid dispersed within a low temperature liquid curing agent is provided. An adhesive system including the cure system is provided, and an associated method. A device including the cured adhesive system is provided.