Semiconductor Common Electrode Trenches for Thermal Warping
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Solution Overview
Problem
Semiconductor devices with shared transistors face challenges in thermal expansion, leading to warping and mounting defects due to the differing linear expansion coefficients of metal electrodes and the semiconductor substrate, which complicates singulation and mounting on wiring substrates.
Innovation Solution
The implementation of trenches in the common electrode and source electrodes to reduce volume, create unevenness, and manage thermal expansion, while maintaining a thicker common electrode to minimize on-resistance and enhance bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common electrode is made thicker to minimize on-resistance, then the electrical performance is improved, but the thermal expansion difference causes warping and mounting defects
Solution Approach 1:
The common electrode is divided into multiple segments by forming trenches that extend from the front surface toward the back surface. This segmentation reduces the continuous metal volume while maintaining electrical connectivity through the trenches, thereby reducing thermal expansion effects and warping while preserving low on-resistance characteristics
Solution Approach 2:
The common electrode is designed with a porous or hollow structure by forming trenches that create voids within the electrode material. This reduces the overall metal volume and thermal mass, minimizing thermal expansion differences with the semiconductor substrate while maintaining sufficient electrical conductivity for low on-resistance
2Stability of the object's composition
If the metal electrode volume is reduced to suppress thermal expansion, then warping is suppressed, but the bonding strength may be compromised
Solution Approach 1:
The trenches segment the metal electrode into multiple regions, reducing overall volume and thermal expansion while the segmented structure maintains adequate bonding surface area. The segmentation allows the electrode to bond at multiple discrete locations rather than requiring continuous large-area bonding
Solution Approach 2:
The electrode structure combines metal material with void spaces created by trenches, forming a composite structure that reduces thermal mass and expansion while maintaining bonding capability through the remaining metal portions. The composite structure optimizes the balance between thermal properties and mechanical bonding strength
3Stability of the object's composition
If trenches are formed in the common electrode to reduce volume, then thermal expansion is managed, but the manufacturing complexity increases
Solution Approach 1:
The trench formation process segments the electrode manufacturing into manageable steps that can be integrated into existing fabrication processes, reducing thermal expansion through geometric design rather than requiring complex material science solutions
Solution Approach 2:
The complex thermal expansion management problem is solved by a simple geometric modification (trenches) rather than complex material compositions or active control systems. The mechanical structure itself manages the thermal expansion through its geometry
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
This approach effectively suppresses warping caused by thermal expansion, maintains low on-resistance, and improves bonding strength, thereby facilitating easier singulation and reliable mounting on wiring substrates.
Implementation Method 1
the differing linear expansion coefficients of metal electrodes and the semiconductor substrate, which complicates singulation and mounting on wiring substrates
Data Source
AI summary
A semiconductor device includes a semiconductor part including a first surface, a second surface, a first region provided between the first surface and the second surface, and a second region provided between the first surface and the second surface; a common electrode provided at the second surface; a first electrode provided on the first surface at the first region; a second electrode provided on the first surface at the second region and separated from the first electrode; a first control electrode provided in the first region; and a second control electrode provided in the second region. A first trench is provided in the common electrode.