Self-Aligned Spacer Fabrication for Semiconductor Contact Plugs
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Solution Overview
Problem
Current methods for creating self-aligned contacts in semiconductor devices often damage the substrate, compromising device performance due to limitations in achieving high-density contact openings.
Innovation Solution
A method involving the formation of composite self-aligned spacers, comprising a nitride-containing material layer and a silicon oxide layer, which are etched to define a recess for a contact plug, allowing for the creation of self-aligned contacts without damaging the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If self-aligned contact is created using prior art approaches with spacers formed on gates, then contact openings can be formed, but the substrate is damaged during the fabricating process
Solution Approach 1:
The spacer structure is divided into two separate layers: a first spacer layer and a second spacer layer. This segmentation allows each layer to perform specific functions - the first layer provides structural support while the second layer defines the contact opening, thereby preventing substrate damage during fabrication
Solution Approach 2:
The first spacer layer acts as an intermediary protective layer between the gate structure and the substrate. During etching processes, this intermediate layer protects the substrate from damage while still allowing the second spacer layer to define the contact opening precisely
2Productivity
If circuit density is increased by building high aspect ratio contact plugs, then interlayer connections are improved, but current technology cannot make contact openings at such high density
Solution Approach 1:
The invention transitions from a single-layer spacer approach to a two-layer spacer structure, adding a dimensional layer to the spacer system. This enables precise control of contact opening dimensions and positioning, allowing high-density contact openings to be formed with accurate alignment
Solution Approach 2:
The first spacer layer is formed in advance to establish a protective and structural foundation before the second spacer layer is formed. This preliminary action enables subsequent precise patterning of the contact openings at high density without compromising substrate integrity
Data Source
AI summary
A method of fabricating a semiconductor with self-aligned spacer includes providing a substrate. At least two gate structures are disposed on the substrate. The substrate between two gate structures is exposed. A silicon oxide layer is formed to cover the exposed substrate. A nitride-containing material layer covers each gate structure and silicon oxide layer. Later, the nitride-containing material layer is etched to form a first self-aligned spacer on a sidewall of each gate structure and part of the silicon oxide layer is exposed, wherein the sidewalls are opposed to each other. Then, the exposed silicon oxide layer is removed to form a second self-aligned spacer. The first self-aligned spacer and the second self-aligned spacer cooperatively define a recess on the substrate. Finally, a contact plug is formed in the recess.