FinFET SDB Formation via Patterned Hard Mask Etching
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Solution Overview
Problem
Current FinFET fabrication processes for forming single diffusion break (SDB) structures face the risk of adjacent SDB structures merging, which complicates the control of critical dimensions and increases the likelihood of fabrication errors.
Innovation Solution
A method involving the formation of a patterned hard mask on a shallow trench isolation (STI) around fin-shaped structures, where parts of the fin-shaped structures adjacent to the mask are removed to create recesses, and dielectric material is deposited into these recesses to form SDB structures, thereby improving the separation and control of fin-shaped structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current FinFET fabrication process is used to form SDB structures, then fin-shaped structures can be created, but adjacent SDB structures may merge and control of critical dimensions becomes difficult
Solution Approach 1:
A patterned hard mask is formed on the STI surface before etching the fin-shaped structures. This preliminary masking step defines the precise locations where SDB structures will be formed, ensuring that the etching process only removes material in the intended areas and prevents merging of adjacent SDB structures.
Solution Approach 2:
The patterned hard mask acts as an intermediary element between the STI and the etching process. It temporarily protects certain areas from etching while allowing etching in other areas, enabling precise control over the formation and separation of SDB structures without direct contact between adjacent structures during processing.
2Productivity
If fin-shaped structures are formed with close spacing, then device density increases, but separation control between structures becomes more difficult
Solution Approach 1:
The STI surface is segmented into different regions using the patterned hard mask, with some areas marked for etching (SDB formation) and others protected. This segmentation allows independent control of each fin-shaped structure's SDB formation, maintaining precise separation even when structures are closely spaced for high device density.
Solution Approach 2:
The patterned hard mask provides local protection to specific areas of the STI, creating different etching conditions in different locations. Areas under the hard mask remain protected while adjacent areas are etched to form SDB structures, enabling precise local control over structure separation and geometry.
Data Source
AI summary
A method for fabricating semiconductor device is disclosed. First, a first fin-shaped structure and a second fin-shaped structure are formed on a substrate, and a shallow trench isolation (STI) is formed around the first fin-shaped structure and the second fin-shaped structure, a patterned hard mask is formed on the STI. Next, part of the first fin-shaped structure and part of the second fin-shaped structure adjacent to two sides of the patterned hard mask are removed for forming a first recess and a second recess, and a dielectric material is formed into the first recess and the second recess.