Composite Thermal Interface Material Structure for Semiconductor Packaging
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Solution Overview
Problem
The challenge in semiconductor packaging is efficient heat dissipation, as the existing methods struggle to effectively transfer heat from densely packed, high-power consumption microelectronic devices to heat spreaders, leading to thermal resistance and potential cracking of semiconductor dies during thermal processes.
Innovation Solution
A composite thermal interface material (TIM) structure is formed between semiconductor dies and heat-dissipating features, comprising a metal-containing matrix material layer with polymer particles coated in a metal cover, which provides thermal conductivity, mechanical support, and a stress buffer to mitigate cracking and achieve uniform thickness, thereby enhancing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple thermal interface material is used between semiconductor dies and heat spreader, then the device complexity is reduced, but the thermal resistance increases and heat dissipation efficiency deteriorates
Solution Approach 1:
The patent applies composite materials by combining metal particles (high thermal conductivity) with polymer matrix (mechanical flexibility and stress buffering). This creates a thermal interface material that simultaneously achieves low thermal resistance and mechanical compliance, resolving the contradiction between simple structure and effective heat dissipation.
Solution Approach 2:
The patent implements local quality by incorporating metal particles with high thermal conductivity specifically in regions where heat transfer is most critical. The composite structure provides enhanced thermal properties at the thermal interface while maintaining overall structural integrity and mechanical compliance throughout the material.
2Loss of energy
If high thermal conductivity material is used to improve heat dissipation, then the thermal resistance is reduced, but the material becomes rigid and may cause cracking of semiconductor dies during thermal processes
Solution Approach 1:
The composite material combines rigid metal particles (for thermal conductivity) with a flexible polymer matrix (for stress buffering). This combination allows the material to conduct heat effectively while accommodating thermal expansion differences and preventing die cracking through mechanical compliance.
Solution Approach 2:
The patent changes the physical and mechanical parameters of the thermal interface material by adjusting the metal particle size, concentration, and distribution within the polymer matrix. These parameter adjustments optimize both thermal conductivity and mechanical compliance to prevent die cracking while maintaining effective heat dissipation.
3Reliability
If the thermal interface material is made thicker to provide better stress buffering, then the reliability improves, but the thermal resistance increases and heat dissipation efficiency deteriorates
Solution Approach 1:
The composite structure allows the material to achieve effective stress buffering at reduced thickness because the metal particles provide rigid support while the polymer matrix provides flexibility. This enables thinner material sections that maintain both mechanical compliance and thermal conductivity, avoiding the trade-off between thickness and thermal resistance.
Solution Approach 2:
The patent applies local quality by concentrating metal particles in regions where stress buffering is most needed while maintaining continuous thermal pathways. This localized enhancement allows thinner overall material thickness while preserving both mechanical support and thermal conductivity.
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 composite TIM structure effectively reduces thermal resistance and prevents cracking of semiconductor dies, improving heat dissipation and the reliability of semiconductor packages by providing a robust and efficient thermal interface.
Implementation Method 1
The metal-containing matrix material layer provides good thermal conductivity, so that the heat generated by the semiconductor dies can be effectively transferred to the heat-dissipating feature
Implementation Method 2
The polymer particle coated with the metal cover provides a stress buffer for the semiconductor die, so as to prevent or mitigate the formation of cracks in the semiconductor die during the thermal process
Data Source
AI summary
A method of forming a semiconductor package is provided. The method includes forming a metallization stack over a semiconductor die. Polymer particles are mounted over the metallization stack. Each of the polymer particles is coated with a first bonding layer. A heat spreader lid is bonded with the semiconductor die by reflowing the first bonding layer. A composite thermal interface material (TIM) structure is formed between the heat spreader lid and the semiconductor die during the bonding. The composite TIM structure includes the first bonding layer and the polymer particles embedded in the first bonding layer.