Thermal Interface Structure With Glass Transition for Semiconductor Packages
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Solution Overview
Problem
Current thermal interface materials (TIM) for semiconductor devices face challenges in providing safe handling at room temperature while maintaining softness and conformity at operating temperatures, which is essential for reliable heat dissipation and electrical insulation.
Innovation Solution
A semiconductor device package is developed with an electrically insulating and thermally conductive interface structure made of an epoxy resin matrix filled with filler particles, such as metal oxides or nitrides, having a glass transition temperature between -40°C to 150°C. This interface structure is designed to provide hardness and scratch resistance at room temperature and softness and compressibility at operating temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone-based thermal interface material is used to achieve high thermal conductivity and snug fit, then thermal performance is improved, but handling safety deteriorates due to sensitivity to scratches
Solution Approach 1:
The patent employs a composite material consisting of a thermoplastic polymer matrix combined with thermally conductive filler particles (such as aluminum oxide, aluminum nitride, or boron nitride). This composite structure achieves high thermal conductivity through the filler particles while the thermoplastic matrix provides scratch resistance and handling safety, resolving the contradiction between thermal performance and mechanical durability.
Solution Approach 2:
The patent utilizes the glass transition temperature parameter of the thermoplastic polymer to achieve parameter change. Below Tg, the material is hard and scratch-resistant for safe handling; above Tg, the material becomes soft and compliant for good thermal contact. This parameter change based on temperature allows the material to exhibit different properties at different stages of use, resolving the contradiction between handling safety and thermal performance.
2Ease of operation
If attachable foil thermal interface material is used to improve handling, then ease of operation is improved, but thermal performance deteriorates due to high contact resistance
Solution Approach 1:
The patent utilizes the glass transition temperature parameter change of thermoplastic polymers to achieve softness and conformability at operating temperatures. When heated above Tg, the material becomes viscous and compliant, allowing it to conform to surface irregularities and reduce thermal contact resistance, thereby maintaining good thermal performance while retaining the handling advantages of foil-based materials.
Solution Approach 2:
The patent applies the principle of local quality by allowing different regions of the thermal interface material to exhibit different properties at different times. During handling and installation (below Tg), the material is hard and structurally stable. During operation (above Tg), the material becomes soft and compliant at the contact interface with the heatsink, ensuring low thermal contact resistance while maintaining overall structural integrity.
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 proposed solution effectively addresses the need for a TIM that is safe to handle at room temperature and thermally conductive at operating temperatures, enhancing the reliability of heat dissipation and electrical insulation in semiconductor devices.
Implementation Method 1
the interface structure (30) comprises a glass transition temperature in a range between -40° C. to 150° C.
Data Source
AI summary
A semiconductor device package comprises an electrically conductive carrier, a semiconductor die disposed on the carrier, an encapsulant encapsulating part of the carrier and the semiconductor die, an electrically insulating and thermally conductive interface structure, in particular covering an exposed surface portion of the carrier and a connected surface portion of the encapsulant, wherein the interface structure comprises a glass transition temperature in a range between −40° C. to 150° C.