Semiconductor Chip Step Surface Light Shielding for Resin Reliability
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Solution Overview
Problem
Semiconductor devices using wide band gap semiconductors face deterioration of sealing resins due to light generated by electron and hole recombination, particularly at the chip end portion, which affects the reliability and longevity of the device.
Innovation Solution
A semiconductor device design featuring a wide band gap semiconductor substrate with an active region, edge termination region, and dicing line, where a step surface is created between the edge termination and dicing line, covered with a first protective film of low light transmittance, specifically a black polyimide film or non-doped polysilicon, to block light emitted from the drift region, thereby preventing resin deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a wide band gap semiconductor device is used to achieve high voltage and high temperature operation, then the device performance is improved, but light is generated by electron and hole recombination that deteriorates the sealing resin
Solution Approach 1:
A light blocking film is introduced as an intermediary layer between the semiconductor chip and the sealing resin. This film blocks the harmful light generated by electron and hole recombination in the wide band gap semiconductor, preventing the light from reaching and deteriorating the sealing resin, while allowing the semiconductor device to maintain its high performance operation
Solution Approach 2:
The harmful light generated by electron and hole recombination is blocked by the light blocking film, converting this harmful effect into a benefit by protecting the sealing resin from deterioration. The light that would have degraded the resin is now contained and used only for its intended functional purpose in the semiconductor device
2Reliability
If a light blocking film is added to block light and prevent resin deterioration, then the reliability is improved, but the device structure becomes more complex
Solution Approach 1:
A thin light blocking film is applied to the chip side surface of the semiconductor chip. This thin film structure provides effective light blocking to prevent resin deterioration while adding minimal structural complexity and maintaining a compact device design
Solution Approach 2:
The light blocking function is implemented by applying a film to the side surface (chip side surface) of the semiconductor chip, utilizing the lateral dimension to block light before it reaches the sealing resin, rather than adding complex three-dimensional structures
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 light-induced deterioration of the sealing resin, enhancing the reliability and longevity of the semiconductor device by blocking blue light and ultraviolet light, ensuring better adhesion and film properties.
Implementation Method 1
the first protective film having a low light transmittance... The first protective film has a light transmittance of 5% or less in a visible light wavelength region
Data Source
AI summary
A semiconductor device includes an active region, which is a region where main current flows, an edge termination region surrounding the active region, a step surface surrounding the edge termination region, and a dicing line surrounding the step surface. The active region has a first pn junction of a first semiconductor region and a second semiconductor layer and a second pn junction of an outer peripheral region and the second semiconductor layer. The step surface is provided with a first protective film for shielding light generated as forward current flows through the first and second pn junctions in the active region.