Semiconductor Heat Sink Bonding Protrusion Adhesive Separation
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Solution Overview
Problem
Semiconductor devices experience adhesive separation from the substrate due to thermal stress, leading to increased thermal resistance and electrical impedance, especially when the heat sink is electrically connected, causing electromagnetic shielding failures.
Innovation Solution
The use of protrusions on the substrate, bonded to the heat sink with an adhesive, acts as an anchor to reduce adhesive separation and enhance bonding strength, thereby maintaining effective heat dissipation and electromagnetic shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thermally conductive adhesive is used to secure the heat sink to the substrate, then the heat sink can be bonded to the substrate, but thermal stress causes separation of the adhesive from the substrate
Solution Approach 1:
The adhesive bonding area is segmented into multiple regions: a first adhesive bonding area directly bonding the heat sink to the substrate, and a second adhesive bonding area extending from the first area to bond the protrusion to the substrate. This segmentation allows different portions of the adhesive structure to bear different mechanical loads, with the protrusion serving as a stress distribution element that prevents concentrated stress at single bonding points.
Solution Approach 2:
The protrusion acts as an intermediary mechanical element between the heat sink and the substrate. It provides an additional bonding interface that distributes thermal stress away from the primary adhesive bonding area, preventing adhesive separation while maintaining thermal conduction path integrity.
2Adaptability or versatility
If the substrate undergoes deformation due to thermal stress, then the substrate responds to heat expansion and contraction, but this causes separation of the adhesive from the substrate
Solution Approach 1:
The adhesive structure is designed to dynamically accommodate substrate deformation through the protrusion element. The protrusion can elastically deform or shift position in response to thermal expansion and contraction, allowing the adhesive bonding areas to maintain integrity while adapting to changing dimensional conditions of the substrate.
Solution Approach 2:
The design changes the geometric parameters of the bonding structure by introducing a protrusion with specific dimensions and positioning. This creates a multi-area bonding configuration that can accommodate parameter changes in the substrate due to thermal stress, maintaining bonding strength through distributed stress accommodation.
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 solution effectively reduces adhesive separation from the substrate, maintaining low thermal resistance and electrical connectivity, ensuring reliable heat dissipation and electromagnetic shielding performance.
Implementation Method 1
a first adhesive disposed between the first surface and the heat sink to bond the first protrusion and the heat sink
Data Source
AI summary
A semiconductor device includes a substrate and a semiconductor element mounted on the top surface of the substrate. On the top surface of the substrate, one or more pads are disposed outside the mounted semiconductor element when seen in a plan view. Then, a protrusion is disposed on each of the pads. A heat sink is disposed above the semiconductor element and the protrusions, and then bonded to the substrate by an adhesive provided between the heat sink and the substrate. The adhesive is provided in such a manner as to be in contact with the protrusions on the substrate.