Semiconductor Package Beam Structure for Thermal Deformation Control
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Solution Overview
Problem
Power semiconductor devices face deformation issues due to thermal expansion and contraction, which can lead to peeling of sealing insulating materials and disconnection of wiring, reducing their reliability and operability as maximum operable temperatures increase.
Innovation Solution
A semiconductor device design that includes a semiconductor element mounted on a base plate, a frame-shaped case, a flat plate-shaped beam with a smaller linear expansion coefficient than the sealing insulating material, and a sealing insulating material filling the internal space, where the beam is positioned above the semiconductor element to reduce thermal deformation and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the maximum operable temperature of the power semiconductor device is increased, then the device can operate at higher temperatures, but deformation caused by thermal expansion and thermal contraction increases
Solution Approach 1:
The patent changes the physical parameter of the beam material by selecting a material with a linear expansion coefficient smaller than that of the sealing insulating material. This parameter difference creates a compensatory effect where the beam's smaller thermal expansion counteracts the sealing insulating material's larger thermal expansion, thereby reducing overall deformation of the semiconductor device at high operating temperatures.
Solution Approach 2:
The patent utilizes the differential thermal expansion between two materials (beam and sealing insulating material) to achieve a beneficial effect. The beam's smaller linear expansion coefficient causes it to expand less than the sealing insulating material when heated, creating an internal constraint that reduces the total thermal deformation of the device structure.
2Reliability
If the linear expansion coefficient of the sealing insulating material is increased to match the semiconductor element, then thermal deformation is reduced, but the sealing insulating material becomes more susceptible to peeling and disconnection
Solution Approach 1:
The beam acts as an intermediary structural element between the semiconductor element and the sealing insulating material. It provides mechanical support and stress distribution, preventing direct stress concentration at the sealing insulating material interfaces. This intermediary structure reduces both thermal deformation and the risk of peeling/disconnection by distributing thermal stresses more evenly across the device.
Solution Approach 2:
The patent creates a composite structure combining the beam material and sealing insulating material with different linear expansion coefficients. This composite configuration allows the beam to bear mechanical loads and provide structural stability while the sealing insulating material provides electrical insulation and sealing, with the differential expansion properties working together to reduce overall device deformation.
3Reliability
If a beam with a smaller linear expansion coefficient than the sealing insulating material is added, then thermal deformation is reduced, but the device structure becomes more complex
Solution Approach 1:
The beam is designed to serve multiple functions simultaneously: it provides mechanical support to the semiconductor element, distributes thermal stresses, reduces overall device deformation through its differential expansion properties, and prevents peeling of the sealing insulating material. By consolidating these multiple functions into a single component, the patent reduces structural complexity compared to using separate elements for each function.
4Manufacturing precision
If the beam covers the semiconductor element in plan view, then local deformation around the semiconductor element is reduced, but the manufacturing process becomes more difficult
Solution Approach 1:
The patent addresses the positioning challenge by transitioning from two-dimensional planar alignment to three-dimensional spatial configuration. The beam extends in the thickness direction above the semiconductor element, providing coverage and stress distribution in the vertical dimension. This dimensional approach simplifies manufacturing by allowing the beam to be positioned and secured in the thickness direction rather than requiring precise alignment solely in the planar direction.
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 design effectively reduces deformation and stress around the semiconductor element, improving the reliability of the device by minimizing peeling and disconnection risks, even at higher temperatures, and maintaining productivity without compromising assemblability.
Implementation Method 1
the linear expansion coefficients of materials constituting the power semiconductor device vary, the semiconductor device is deformed by the heat generation
Implementation Method 2
reduces deformation due to thermal expansion and thermal contraction
Data Source
AI summary
A semiconductor device includes a semiconductor element, a case, a beam, and a sealing insulating material. The semiconductor element is mounted on a base plate. The case has a frame shape in plan view. The case is attached to the base plate. The case houses the semiconductor element inside the frame shape. The beam has a flat plate shape. The beam is held by the case. The beam is held over an internal space that is a space inside the frame shape of the case. The sealing insulating material fills the internal space of the case and covers at least a part of the beam. The beam is provided above the semiconductor element and covers the semiconductor element in plan view.