Wide Bandgap Semiconductor Electric Field Relaxation
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Solution Overview
Problem
Wide band gap semiconductor materials, such as SiC, require a high dielectric breakdown intensity sealing material due to increased electric field intensity, but existing silicone gel sealing methods fail to adequately relax electric fields at the semiconductor chip's peripheral edge, leading to potential dielectric breakdown and increased manufacturing costs.
Innovation Solution
A high electric field resistance sealing member with a thicker film thickness and a specific shape, including inclined or projected sections, is applied between the semiconductor chip and the silicone gel to effectively relax electric fields without increasing the size of the termination part, thereby enhancing the reliability and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard thickness sealing member is used, then the device structure is simple and manufacturing is easy, but the electric field intensity exceeds the dielectric breakdown intensity of the sealing material causing reliability issues
Solution Approach 1:
The sealing member employs varying film thicknesses in different regions: a first film thickness in the first region and a second film thickness (greater than the first) in the second region. This local quality variation allows the sealing member to provide enhanced dielectric strength where needed while maintaining overall structural simplicity, resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The invention transitions from a uniform two-dimensional sealing layer to a three-dimensional structure with varying thickness. By introducing the thickness dimension as a variable parameter across different regions, the sealing member achieves higher dielectric breakdown resistance without proportionally increasing overall device complexity.
2Reliability
If the termination part size is increased to relax electric fields, then electric field relaxation is improved, but the manufacturing cost increases
Solution Approach 1:
The invention changes the parameter of film thickness rather than increasing the termination part area. By varying the thickness parameter of the sealing member across different regions, effective electric field relaxation is achieved without expanding the termination part size, thereby avoiding increased manufacturing costs.
3Reliability
If the sealing member film thickness is increased, then dielectric breakdown resistance is improved, but the device size and manufacturing complexity increase
Solution Approach 1:
Instead of uniformly increasing the sealing member thickness across the entire device, the invention applies a greater second film thickness only in the second region where it is most needed for dielectric strength, while maintaining a smaller first film thickness in the first region. This localized approach improves dielectric breakdown resistance without proportionally increasing overall device size.
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 suppresses dielectric breakdown of the silicone gel and improves the reliability of the semiconductor device by thickening the sealing member's film thickness and optimizing its shape to manage electric field relaxation, allowing for a smaller termination part and reduced manufacturing costs.
Implementation Method 1
the intensity of an electric field which is imposed on a sealing body which is in contact with the wide band gap semiconductor material is increased, a sealing material for the wide band gap semiconductor material is requested to be high in dielectric breakdown intensity
Data Source
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AI summary
In a semiconductor device (SA1) which uses a wide band gap semiconductor material which is larger than silicon in band gap, reliability of the semiconductor device (SA1) is improved by realizing a structure which relaxes intensity of an electric field on the vicinity of an outer end part of a semiconductor chip (CHP1) . For example, the semiconductor device (SA1) includes the semiconductor material which is larger than silicon in band gap and includes the semiconductor chip (CHP1) which has a high electric field resistance sealing member (MR) which covers a peripheral edge part of an element formation face and a silicone gel (GL) which covers the semiconductor chip (CHP1). At this time, an end face of the semiconductor chip (CHP1) and an outer end part of the high electric field resistance sealing member (MR) include parts which are flush with each other, and dielectric breakdown electric field intensity of the high electric field resistance sealing member (MR) is larger than dielectric breakdown electric field intensity of the silicone gel (GL).