Multi-Layer Contact Plug Structure for Semiconductor Device Isolation
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Solution Overview
Problem
As the thickness of insulating films in semiconductor devices increases, it becomes difficult to secure a contact area and completely fill contact holes with conductive material, leading to open defects and high contact resistance between contact plugs and underlying structures.
Innovation Solution
The semiconductor device employs a multi-layer structure with first and second contact plugs made of different conductive materials, where the first contact plug is formed in the first and second interlayer insulating films, and the second contact plug is formed in the second interlayer insulating film, using barrier metal films and conductive materials like tungsten and copper to ensure reliable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of insulating films is increased, then device integration and isolation are improved, but contact hole filling becomes difficult and open defects increase
Solution Approach 1:
The contact plug structure is segmented into multiple parts: a first contact plug formed in the first interlayer insulating film, and a second contact plug formed in the second interlayer insulating film. This segmentation allows each contact plug to be optimized independently for its specific insulating film thickness, solving the problem of difficult contact hole filling in thick insulating films while maintaining device isolation.
Solution Approach 2:
The invention transitions from a single contact plug approach to a multi-layer contact plug structure spanning multiple interlayer insulating films. By adding the vertical dimension of multiple film layers, the solution accommodates varying insulating film thicknesses and ensures complete filling without open defects.
2Device complexity
If a single contact plug structure is used, then device complexity is reduced, but contact resistance and open defects increase
Solution Approach 1:
The contact structure is divided into multiple contact plugs formed in different interlayer insulating films. This segmentation improves reliability by providing multiple contact points and reducing open defects, while the modular approach keeps the manufacturing process manageable and not excessively complex.
Solution Approach 2:
The first contact plug is formed in the first interlayer insulating film before the second interlayer insulating film is formed. This preliminary action ensures proper contact area and filling in the first film, and the second contact plug is subsequently formed to complete the connection through the second film, achieving reliable contact connection through staged manufacturing.
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes: a substrate; device isolation regions formed in the substrate; an impurity region formed in a region of the substrate between every two adjacent ones of the device isolation regions; a gate electrode formed on the substrate; first and second interlayer insulating films sequentially formed on the substrate; a metal interlayer insulating film formed on the second interlayer insulating film and comprising metal wiring layers; a first contact plug electrically connecting each of the metal wiring layers and the impurity region; and a second contact plug electrically connecting each of the metal wiring layers and the gate electrode, wherein the first contact plug is formed in the first and second interlayer insulating films, and the second contact plug is formed in the second interlayer insulating film.