ESD Protection Structure With Stepped Isolation For Via Formation
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Solution Overview
Problem
The existing semiconductor devices face challenges in integrating an ESD protection module due to the difficulty in forming interlayer vias across a large transition step between the MOSFET and the ESD protection module, which affects electrical conductivity and increases manufacturing complexity and cost.
Innovation Solution
A semiconductor device structure with an ESD protection structure featuring a first isolation layer and an ESD protection layer, where the middle portion has a greater thickness than the first and second portions, facilitating the formation of interlayer vias in a single manufacturing step by reducing the transition step height and improving precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick isolation layer is used to electrically isolate the ESD protection module from the substrate, then electrical isolation is improved, but the transition step height increases making via formation difficult
Solution Approach 1:
The isolation layer is segmented into two distinct layers: a first isolation layer directly on the substrate and a second isolation layer on top of it. This segmentation allows the second isolation layer to be thinner, enabling precise via formation through both layers while maintaining the required electrical isolation through the combined thickness of both layers.
Solution Approach 2:
The solution addresses the height problem by distributing the isolation function across multiple layers in the vertical dimension rather than using a single thick layer. This dimensional distribution reduces the transition step height at any single location, facilitating via formation while preserving overall isolation performance.
2Area of stationary object
If the ESD protection module is integrated into the semiconductor device, then device size is reduced, but the complex transition step structure increases manufacturing complexity
Solution Approach 1:
Dividing the isolation structure into two layers simplifies the manufacturing process by enabling via formation through both layers in a single step, reducing the overall manufacturing complexity despite maintaining device integration.
Solution Approach 2:
By changing the thickness parameter of the second isolation layer to be smaller than that of the first isolation layer, the transition step height is optimized for via formation while maintaining electrical isolation, thus reducing manufacturing complexity.
3Reliability
If a single thick isolation layer is used, then electrical isolation is achieved, but multiple via formation steps are required increasing manufacturing cost
Solution Approach 1:
The isolation layer is divided into two layers with different thicknesses, allowing vias to be formed through both layers in a single manufacturing step. This eliminates the need for multiple via formation steps, reducing manufacturing cost while maintaining electrical isolation.
Solution Approach 2:
The two-layer isolation structure is prepared in advance with optimized thicknesses, enabling subsequent via formation to be completed in a single step. This preliminary structuring reduces the number of manufacturing steps required.
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 configuration enhances the formation of interlayer vias with improved precision and reduces the risk of failure, allowing for more efficient electrical conductivity between the gate and source regions while simplifying the manufacturing process.
Implementation Method 1
the first isolation layer is disposed between the ESD protection layer and the substrate to isolate the ESD protection layer from the substrate
Implementation Method 2
The ESD protection module is configured to provide a conduction path between the source and the gate of the semiconductor device, once a gate to source voltage of the semiconductor device caused by ESD exceeds an ESD threshold voltage, so that a large extra energy due to ESD can be discharged promptly through the conduction path
Data Source
AI summary
A semiconductor device having an ESD protection structure and a method for forming the semiconductor device. The ESD protection structure is formed atop a termination area of the substrate and is electrically coupled between a source metal and a gate metal of the semiconductor device. The ESD protection structure has a first portion adjacent to the source metal, a second portion adjacent to the gate metal and a middle portion between and connecting the first portion and the second portion, wherein the middle portion has a first thickness greater than a second thickness of the first portion and the second portion. Such an ESD protection structure is beneficial to the formation of interlayer vias which are formed to couple the ESD protection structure to the source metal and the gate metal.