Via Hole Fabrication with Etch Stop Patterns for Density Control
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Solution Overview
Problem
As semiconductor devices shrink in size and increase in performance, the density difference between isolation via-holes and dense via-holes becomes significant, leading to process margin issues and increased parasitic capacitance when dummy vias are used to mitigate this difference.
Innovation Solution
A method is developed to fabricate semiconductor devices by forming an interlayer insulating layer with distinct regions, creating specific via-holes and etch stop patterns to control the depth and placement of metal wirings, allowing for the reduction of density differences between isolation and dense via-holes, thereby improving process margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dimensions of via-holes are decreased to improve device performance, then device performance is improved, but the density difference between isolation via-holes and dense via-holes increases
Solution Approach 1:
The patent applies local quality by forming different types of via-holes (first via-holes and second via-holes) with different depths in different regions. The first via-holes penetrate through the interlayer insulating layer to expose the lower metal wiring, while the second via-holes only expose the etch stop pattern. This local differentiation allows isolation via-holes to have the same depth as dense via-holes, equalizing their density and eliminating proximity effect issues.
2Manufacturing precision
If the number of isolation vias is increased to reduce density difference, then density difference is reduced, but process margin problems occur
Solution Approach 1:
The patent segments the via-hole formation process into two distinct types: first via-holes that penetrate through the interlayer insulating layer and second via-holes that stop at the etch stop pattern. This segmentation allows isolation vias to be formed with the same depth control mechanism as dense vias, reducing density difference without requiring an increased number of isolation vias, thereby maintaining process margin.
3Manufacturing precision
If dummy vias are used to reduce density difference, then density difference is reduced, but parasitic capacitance is increased
Solution Approach 1:
Instead of adding dummy vias to increase density in isolation regions, the patent inverts the approach by making isolation via-holes the same depth as dense via-holes. This is achieved by forming second via-holes that stop at the etch stop pattern, eliminating the need for dummy vias and avoiding the associated parasitic capacitance increase.
Data Source
AI summary
A method for fabricating a semiconductor device is provided. The method for fabricating the semiconductor device includes forming an interlayer insulating layer that comprises a first region and a second region, forming an etch stop pattern for exposing the second region in the first region of the interlayer insulating layer and forming a mask pattern that comprises a first via-hole that exposes an upper surface of the etch stop pattern and a second via-hole that penetrates the interlayer insulating layer on the interlayer insulating layer and the etch stop pattern.