Thin Heat Sink Support Using E-Bar Substrates in Semiconductor Packages
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Solution Overview
Problem
The extension of heat sinks in semiconductor packages beyond three times the thickness of the horizontal portion leads to structural issues such as breakage and warpage, limiting their effectiveness in dissipating heat and contributing to premature failure.
Innovation Solution
The use of e-bar substrates to elevate the heat sink, reducing the need for vertical extensions and maintaining structural integrity by providing a vertical offset, thus minimizing the overall height and enhancing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the heat sink is extended vertically down to the HDI substrate for structural support, then the heat sink provides structural support, but the heat sink becomes subject to breakage, warpage, and premature failure due to excessive height
Solution Approach 1:
The heat sink structure is divided into two separate components: a horizontal heat sink portion and a vertical support portion. This segmentation allows each component to be optimized independently - the horizontal portion can be kept thin and robust while the vertical support provides necessary structural elevation without compromising the heat sink's durability
Solution Approach 2:
The patent introduces an intermediary support structure (vertical support portion) that mediates between the heat sink and the HDI substrate. This intermediary provides the necessary structural support and elevation without requiring the heat sink itself to extend vertically, thus preventing breakage and warpage while maintaining structural integrity
2Length of stationary object
If the heat sink vertical extension length exceeds 3 times the thickness of the horizontal portion, then the heat sink reaches the HDI substrate for support, but the heat sink is subject to breakage and warpage
Solution Approach 1:
By segmenting the heat sink into horizontal and vertical portions, the patent eliminates the need for a long continuous vertical extension. The horizontal portion maintains its thin profile while the separate vertical support provides elevation, avoiding the dimensional instability associated with excessive vertical extension length
Solution Approach 2:
The patent transitions from a vertical extension approach to a horizontal support approach. Instead of extending the heat sink vertically downward, the support function is achieved through a horizontal portion that extends laterally, fundamentally changing the dimensional approach to solving the support problem
3Reliability
If the heat sink vertical extension is limited to 3 times the thickness of the horizontal portion, then the heat sink maintains structural integrity, but the heat sink cannot reach the HDI substrate for adequate support in tall semiconductor packages
Solution Approach 1:
The heat sink system is segmented into a horizontal heat dissipation portion and a vertical support portion. This allows the horizontal portion to maintain its thin, structurally sound design while the vertical support portion independently provides the necessary reach to the HDI substrate, solving both structural integrity and support reach requirements
Solution Approach 2:
A vertical support portion acts as an intermediary element that bridges the gap between the thin horizontal heat sink and the HDI substrate. This intermediary provides the necessary vertical reach and structural support without compromising the horizontal heat sink's integrity or requiring it to be thickened
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
E-bar substrates support the heat sink, reducing defects and ensuring effective heat dissipation while maintaining robustness, addressing the limitations of conventional heat sink designs.
Implementation Method 1
improving heat dissipation... E-bar substrates support the heat sink, reducing defects and ensuring effective heat dissipation
Data Source
AI summary
A semiconductor device has a substrate and a semiconductor package disposed over the substrate. An embedded bar (e-bar) substrate is disposed on the substrate around the semiconductor package. A heat sink is formed over the semiconductor package and supported by the e-bar substrate to elevate the heat sink from the substrate and reduce a thickness of the heat sink. A thermal interface material is deposited between the semiconductor package and heat sink. Alternatively, a shield layer can be formed over the semiconductor package and supported by the e-bar substrate. The e-bar substrate has a base layer and a first metal layer formed over a first surface of the base layer. A bump is formed over the first metal layer. A second metal layer can be over a second surface of the base layer opposite the first surface of the base layer. Two or more e-bar substrates can be stacked.