Electrostatic Protection Stack Wiring for Low-Resistance Surge Discharge
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Solution Overview
Problem
Existing electrostatic protection elements in semiconductor integrated circuits face challenges in efficiently discharging surge voltage due to high resistance in the discharge path, which can lead to excessive heat generation and deterioration of semiconductor characteristics.
Innovation Solution
The electrostatic protection element incorporates a stack structure with multilayer wiring connected to contact layers, reducing the resistance of the discharge path by integrating contact and through hole structures, thereby enabling efficient surge discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional wiring structure with through holes and multiple contact layers is used to connect the electrostatic protection element to the semiconductor substrate, then the connection is electrically functional, but the resistance of the discharge path becomes large due to series connection of multiple resistive elements
Solution Approach 1:
The patent combines the contact layer and through hole into a single integrated stack structure. The first contact layer is formed directly within the through hole that penetrates the insulation film, eliminating the need for separate contact layers and through holes. This merging reduces the number of series-connected resistive elements and lowers the overall discharge path resistance, enabling more efficient surge discharge.
Solution Approach 2:
The patent transitions from a planar wiring structure to a three-dimensional stack structure. Multiple contact layers (first, second, and third contact layers) are vertically stacked within the same through hole region, connected to different wiring layers (first and second layer wirings). This vertical stacking in the third dimension reduces the horizontal spread of the discharge path and minimizes the number of series-connected resistive elements.
2Ease of manufacture
If multiple contact layers and through holes are used to connect different wiring layers, then electrical connection between layers is achieved, but excessive heat is generated during surge discharge due to high discharge resistance
Solution Approach 1:
The patent merges multiple contact layers into a single integrated stack structure within one through hole. The first contact layer connects to the first layer wiring, the second contact layer connects to the second layer wiring, and the third contact layer provides an additional connection point. This consolidation reduces the total resistance of the discharge path, thereby reducing heat generation during surge discharge while maintaining ease of manufacture through a standardized fabrication process.
Solution Approach 2:
The stack structure employs composite material layers including conductive contact layers, insulation films, and wiring layers with different material properties. The contact layers are formed with materials optimized for electrical conductivity, while the insulation films provide electrical isolation. This composite structure enables efficient heat dissipation during surge events while maintaining electrical functionality.
3Ease of manufacture
If conventional separate contact layers and through holes are used, then each component can be manufactured independently, but the overall discharge path resistance increases due to series connection of multiple elements
Solution Approach 1:
The patent combines the fabrication of contact layers and through holes into a single integrated process step. The contact layers are formed within the through holes during the same fabrication sequence, rather than as separate independent steps. This merging maintains ease of manufacture through process integration while significantly reducing the discharge path resistance by eliminating series-connected interfaces between separate components.
Data Source
AI summary
An electrostatic protection element including: a first impurity layer of second conductivity type formed on a semiconductor substrate of first conductivity type; a second impurity layer of the first conductivity type formed within the first impurity layer; a first contact layer of the first conductivity type formed in a region within the first impurity layer other than at the second impurity layer; a second and a third contact layer both of the second conductivity type and formed within the second impurity layer; and multilayer wiring connected through a stack structure to the first, the second, and the third contact layer, wherein the stack structure includes at least a first layer wiring connected to each of the first, the second, and the third contact layer, and a second layer wiring connected to the first layer wiring directly above each of the first, the second, and the third contact layer.