Elastic Heat Spreader Structure for Thermal Expansion Mismatch
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Solution Overview
Problem
The delamination issue between the heat spreader and substrate, as well as the chip, due to different thermal expansion coefficients in large-size semiconductor packaging products, leading to reduced heat dissipation performance.
Innovation Solution
An elastic heat spreader with a top cover plate and a side cover plate that includes an elastic member, allowing telescopic movement, and a grid structure filled with a heat-conducting metal material, along with a supporting portion to stabilize the structure and improve heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the size of the heat spreader is increased to match larger FCBGA packaging products, then the heat dissipation area is improved, but the warpage and stress between the heat spreader and substrate increase due to different thermal expansion coefficients
Solution Approach 1:
The patent introduces an elastic member (comprising elastic columns and elastic beams) between the heat spreader and substrate that acts as a flexible buffer. This elastic structure can deform elastically under thermal stress, accommodating the differential thermal expansion between the heat spreader and substrate without causing delamination or excessive warpage, thus allowing larger heat spreader areas while maintaining structural stability.
Solution Approach 2:
The patent changes the mechanical parameters of the connection structure by introducing elastic elements with specific elastic moduli and geometric parameters (column diameter, beam thickness, etc.). These parameter changes enable the connection structure to have controlled elastic deformation characteristics that match the thermal expansion differences, resolving the contradiction between large area and low warpage.
2Area of stationary object
If the size of the heat spreader is increased to match larger FCBGA packaging products, then the heat dissipation area is improved, but the stress between the heat spreader and substrate increases due to different thermal expansion coefficients
Solution Approach 1:
The elastic member serves as a flexible buffer that absorbs and distributes thermal stress through elastic deformation. The elastic columns and beams are designed with specific geometric parameters to provide appropriate stiffness, reducing the stress concentration between the heat spreader and substrate while maintaining large heat dissipation area.
Solution Approach 2:
The elastic member is pre-installed between the heat spreader and substrate to provide beforehand cushioning against thermal stress. This elastic buffer structure is designed to anticipate and accommodate the thermal expansion differences before they cause damage, reducing the stress between components during temperature changes.
3Stability of the object's composition
If a fixed heat spreader is used, then the structural stability is maintained, but the risk of delamination between the heat spreader and substrate increases due to thermal expansion differences
Solution Approach 1:
The patent replaces the fixed rigid connection with an elastic member comprising elastic columns and beams. This flexible structure maintains structural stability through elastic support while accommodating thermal expansion differences, significantly reducing the risk of delamination between the heat spreader and substrate during temperature cycling.
Solution Approach 2:
The patent transitions from a static fixed connection to a dynamic elastic connection. The elastic member can deform and adapt to thermal stresses in real-time, maintaining structural stability while preventing delamination. The elastic structure provides dynamic response to thermal loading rather than rigid resistance.
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
Reduces the risk of delamination and enhances heat dissipation performance by accommodating thermal expansion, ensuring effective heat transfer from the chip to the surrounding medium.
Implementation Method 1
at least a partial region of the side cover plate is an elastic member; and the elastic member at least enables the side cover plate to be telescopic in a direction perpendicular to the top cover plate
Implementation Method 2
Due to different thermal expansion coefficients of the heat spreader and the substrate, as the size increases, the warpage of the product becomes larger, and the stress between the corresponding heat spreader and the substrate increases
Implementation Method 3
each grid groove is filled with a heat-conducting metal material which covers the grid pieces
Implementation Method 4
the heat generated during chip operation is dissipated into the outside air
Implementation Method 5
Heat generated during chip operation needs to be dissipated to a fluid medium such as air
Data Source
AI summary
The present invention discloses an elastic heat spreader for chip packaging, a packaging structure and a packaging method. The heat spreader includes a top cover plate and a side cover plate that extends outward along an edge of the top cover plate, wherein the top cover plate is configured to be placed on a chip, and at least a partial region of the side cover plate is an elastic member; and the elastic member at least enables the side cover plate to be telescopic in a direction perpendicular to the top cover plate. According to the present invention, a following problem is solved: delamination between the heat spreader and a substrate as well as the chip due to stress generated by different thermal expansion coefficients of the substrate, the heat spreader and the chip in a packaging process of a large-size product.