Semiconductor Package Heat Dissipation via Conductive Posts
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Solution Overview
Problem
Traditional chip packaging methods using leadframes or silver epoxy adhesive layers face limitations in heat conduction due to high thermal resistance and thermal stress, leading to inefficient heat dissipation and potential adhesive layer failure.
Innovation Solution
A semiconductor package structure featuring a dielectric layer, patterned metal layer, carrier with heat conductive posts, and a semiconductor die positioned in a containing cavity, allowing direct heat transfer through heat conductive posts, along with additional layers for protection and stress buffering, enhances heat dissipation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silver epoxy adhesive layer is used to transfer heat from chip to package substrate, then heat transfer path is established, but thermal resistance increases and heat conduction deteriorates
Solution Approach 1:
The patent extracts the heat conduction function from the adhesive layer by introducing a separate heat dissipation structure (heat sink with heat dissipation fins) that directly contacts the chip. This removes the thermal resistance bottleneck caused by the adhesive layer while maintaining its bonding function.
Solution Approach 2:
The patent introduces a heat sink as an intermediary component between the chip and the package substrate. This heat sink with high thermal conductivity material serves as a dedicated heat transfer path, bypassing the thermal limitations of the adhesive layer.
2Strength
If adhesive layer is used to fix chip on package substrate, then mechanical bonding is achieved, but thermal stress destroys the adhesive layer
Solution Approach 1:
The patent separates the mechanical bonding function from the thermal management function. The adhesive layer retains only the bonding function, while the heat sink handles thermal stress dissipation, preventing the adhesive layer from being destroyed by thermal stress.
Solution Approach 2:
The heat sink structure with its high thermal conductivity and heat dissipation fins provides beforehand cushioning against thermal stress by actively managing heat flow, preventing thermal stress accumulation that would otherwise destroy the adhesive layer.
3Ease of operation
If leadframe is used as carrier, then chip mounting is enabled, but bonding point density is limited
Solution Approach 1:
The patent changes the structural parameters of the carrier by replacing the traditional leadframe with a package substrate that has a flattened, planar structure. This structural parameter change enables significantly higher bonding point density while maintaining chip mounting capability.
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 structure achieves better heat dissipation efficiency by directly transferring heat from the semiconductor die to the carrier, reducing thermal resistance and stress on the adhesive layer, thereby improving the reliability and performance of the package.
Implementation Method 1
heat conductive post extends from the fourth surface of the carrier to the through hole and is disposed in the through hole, allowing direct heat transfer through heat conductive posts
Data Source
AI summary
A fabricating method of a semiconductor package structure is provided. A dielectric layer having a first surface and a second surface is provided. A patterned metal layer has been formed on the first surface of the dielectric layer. An opening going through the first and the second surfaces is formed. A carrier having a third surface and a fourth surface is formed at the second surface. A portion of the third surface is exposed by the opening of the dielectric layer. A semiconductor die having a joining surface and a side-surface is joined in the opening. At least a through hole going through the third and the fourth surfaces is formed. A metal layer having at least a heat conductive post extending from the fourth surface of the carrier to the through hole and disposed in the through hole and a containing cavity is formed on the fourth surface.