Replacement Gate Contact Layout to Prevent FinFET Shorting
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Solution Overview
Problem
The semiconductor industry faces challenges in scaling down integrated circuit (IC) manufacturing due to increased complexity and the need for advanced processing techniques to maintain efficiency and cost-effectiveness as geometry sizes decrease and functional density increases.
Innovation Solution
The method involves forming fins on a semiconductor substrate, creating dummy gate structures, replacing them with replacement gate structures, and using a contact etch stop layer and interlayer dielectric layers to prevent electrical shorting and improve manufacturing precision, allowing for precise control of gate and source/drain contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If geometry size is decreased to increase functional density, then production efficiency is improved and costs are lowered, but processing complexity increases
Solution Approach 1:
The fabrication process is divided into multiple sequential stages: forming fins at a first pitch, forming dummy gate structures, selectively removing portions, forming replacement gate structures, and forming source/drain contacts. This segmentation allows complex nanoscale patterning to be achieved through manageable steps, resolving the contradiction between scaling down geometry and managing processing complexity
Solution Approach 2:
The patent transitions from two-dimensional planar transistors to three-dimensional FinFET structures by forming vertical fins protruding from the substrate. This dimensional change increases functional density and electrical performance while maintaining scalability, addressing the challenge of continued miniaturization
2Manufacturing precision
If dummy gate structures are used to maintain structural integrity during fabrication, then manufacturing precision is improved, but additional processing steps are required
Solution Approach 1:
Dummy gate structures are formed in advance before the actual gate structures are created. These preliminary structures provide reference alignment features and structural support during subsequent processing steps, enabling precise placement of replacement gates and source/drain contacts while maintaining ease of fabrication
Solution Approach 2:
The dummy gate structures serve as intermediary elements that facilitate the fabrication process. They act as temporary placeholders and alignment references that are later replaced by the actual gate structures, simplifying the overall manufacturing sequence while improving precision
Data Source
AI summary
A method of forming a semiconductor device includes forming a dummy gate structure across a fin protruding from a substrate, forming gate spacers on opposite sidewalls of the dummy gate structure, forming source/drain epitaxial structures on opposite sides of the dummy gate structure, forming a first interlayer dielectric (ILD) layer on the source/drain epitaxial structures and outer sidewalls of the gate spacers, replacing the dummy gate structure with a replacement gate structure, etching back the replacement gate structure to form a first recess between the gate spacers, forming a source/drain contact in the first ILD layer, and forming a second interlayer dielectric (ILD) layer to fill in the first recess between the gate spacers and over the source/drain contact.