Semiconductor Contact Spacer Layout to Prevent Gate Bridging
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Solution Overview
Problem
As feature sizes in semiconductor devices decrease, the process window for forming conductive contacts is reduced, leading to a bridging problem between conductive contacts and adjacent conductive features, resulting in yield loss and quality test failures.
Innovation Solution
Forming dielectric contact spacers between conductive contacts and adjacent conductive features in a dielectric layer to increase spacing distances and prevent bridging, using a low-k dielectric material and anisotropic etching processes to fully cover sidewalls of contact openings before forming conductive contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feature sizes are reduced to improve integration density, then integration density is improved, but the process window for forming conductive contacts is reduced causing bridging problems
Solution Approach 1:
The patent segments the formation process into multiple steps: first forming a dielectric spacer layer covering the gate structure, then forming contact openings through the dielectric layer, and finally forming conductive contacts in the openings. This segmentation allows precise control of each step independently, maintaining manufacturing precision despite reduced feature sizes.
Solution Approach 2:
The dielectric spacer layer is formed preliminarily before forming the conductive contacts. This preliminary action defines the contact opening locations and dimensions in advance, ensuring that subsequent contact formation occurs at precise positions with adequate spacing from gate structures, thus preventing bridging.
2Reliability
If spacing distances between conductive contacts and gate structures are increased to prevent bridging, then bridging is prevented, but device area increases
Solution Approach 1:
The patent utilizes the vertical dimension by forming a dielectric spacer layer with controlled thickness to achieve the required horizontal spacing. Instead of increasing horizontal spacing directly, the spacer layer's vertical presence defines the contact opening positions, effectively controlling spacing in a different dimensional approach.
Solution Approach 2:
The patent controls the spacing distance by adjusting the thickness parameter of the dielectric spacer layer. By changing this parameter, precise horizontal spacing is achieved between conductive contacts and gate structures, preventing bridging while minimizing area increase.
3Reliability
If dielectric contact spacers are formed to isolate gate structures from conductive contacts, then bridging is prevented, but process complexity increases
Solution Approach 1:
The dielectric spacer layer serves multiple functions: it acts as an isolation barrier between gate structures and conductive contacts, defines the contact opening locations, and controls the spacing distances. This multi-functionality reduces the need for additional separate structures or processes.
Solution Approach 2:
The dielectric contact spacer layer acts as an intermediary element between the gate structure and the conductive contact. It mediates the interaction by providing physical separation and defining the interface, simplifying the overall structure compared to direct contact or complex isolation schemes.
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 method effectively alleviates or eliminates the bridging problem between conductive contacts and gate structures, improving manufacturing yields and reducing quality test failures by increasing spacing distances and isolating gate structures from conductive contacts with dielectric spacers.
Implementation Method 1
anisotropic etching processes to fully cover sidewalls of contact openings
Data Source
AI summary
A method for manufacturing a semiconductor device includes: forming a transistor on a semiconductor substrate, in which the transistor includes a gate structure and a source/drain structure; forming a patterned dielectric layer on the semiconductor substrate, in which the patterned dielectric layer includes an opening extending from a top surface of the patterned dielectric layer to a top surface of the source/drain structure; forming a dielectric contact spacer to cover a sidewall of the opening; and forming a conductive contact in the opening such that the conductive contact is connected to the source/drain structure and is isolated from the gate structure by the dielectric contact spacer and the patterned dielectric layer.