Interconnect Notch Design for Bridging Prevention
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Solution Overview
Problem
As semiconductor devices shrink, the reduced overlay window in multi-layer interconnect structures increases the likelihood of misalignment between upper and lower conductive devices, leading to circuit bridging defects due to exposed lower conductive devices creating bridging paths between adjacent upper conductive devices.
Innovation Solution
An interconnect structure featuring a substrate with a dielectric layer, a first conductive pattern, and a second conductive pattern where the exposed portion of the first conductive pattern has a notch, formed by an etching process using chlorine gas and a protective gas, to prevent bridging paths between adjacent conductive patterns, thereby increasing the overlay window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the overlay window is reduced to increase integration density, then the chip surface utilization is improved, but misalignment between conductive devices occurs more easily
Solution Approach 1:
The patent applies preliminary action by forming a protective coating layer on the lower conductive device before the upper conductive device is formed. This pre-protection measure ensures that even if misalignment occurs during subsequent fabrication steps, the exposed lower conductive device remains insulated and cannot create bridging paths, thus resolving the contradiction between reduced overlay window and alignment precision.
2Adaptability or versatility
If the lower conductive device is exposed due to misalignment, then the multi-layer interconnect design flexibility is improved, but circuit bridging defects occur
Solution Approach 1:
The patent introduces an intermediary protective coating layer between the lower conductive device and the upper conductive device. This intermediary layer allows the lower conductive device to be exposed for design flexibility while simultaneously preventing circuit bridging by providing electrical insulation, thus resolving the contradiction between design flexibility and circuit reliability.
3Quantity of substance
If the exposed lower conductive device creates a bridging path, then the conductive connectivity is improved, but circuit bridging defects are created
Solution Approach 1:
The patent converts the potentially harmful exposure of the lower conductive device into a beneficial situation by applying a protective coating. The coating transforms the exposed conductive surface from a source of bridging defects into a controlled interface that maintains design flexibility while preventing harmful electrical connections, thus resolving the contradiction between conductive connectivity and circuit bridging defects.
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 notch in the exposed portion of the first conductive pattern effectively cuts bridging paths between adjacent conductive patterns, preventing circuit bridging defects and enhancing the overlay window between the second and first conductive patterns.
Implementation Method 1
a forming method of the notch includes partially removing the exposed portion of the first conductive pattern by performing an etching process on the exposed portion of the first conductive pattern with the second conductive pattern as a mask
Data Source
AI summary
An interconnect structure including a substrate, a dielectric layer, a first conductive pattern, and a second conductive pattern is provided. The dielectric layer is disposed on the substrate and has an opening. The first conductive pattern is disposed in the opening. The second conductive pattern is disposed on the first conductive pattern and exposes an exposed portion of the first conductive pattern. The exposed portion of the first conductive pattern has a notch.