FinFET Fin Sidewall Shaping to Prevent Collapse
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices continue to shrink in size, the adhesion forces between adjacent fins in FinFETs can lead to collapse during manufacturing, reducing yield and process reliability.
Innovation Solution
The formation of semiconductor fins is modified to reduce contact area by etching hard mask regions with lateral protrusions and applying a rough film, or roughening the sidewalls of the fins to minimize adhesion forces, thereby reducing the chance of fin collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the minimum feature size is reduced to improve integration density, then more components can be integrated into a given area, but adhesion forces between adjacent fins increase causing fin collapse during manufacturing
Solution Approach 1:
The patent applies curvature by forming the fins with rounded corners instead of sharp edges. This is achieved through the etching process that creates fins with curved sidewalls and rounded top surfaces. The curved geometry reduces the contact area between adjacent fins, thereby minimizing adhesion forces and preventing fin collapse during subsequent manufacturing steps while maintaining high integration density
Solution Approach 2:
The patent changes the geometric parameters of the fins, specifically the aspect ratio and curvature radius. By optimizing these parameters, the fins achieve a shape that minimizes adhesion forces between adjacent structures. The modified geometry allows for reduced minimum feature size without increasing the risk of collapse, thus resolving the contradiction between integration density and manufacturing yield
2Reliability
If the contact area between adjacent fins is reduced to minimize adhesion forces, then fin collapse is prevented, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by forming the curved fin geometry and reducing contact area during the initial etching step. This pre-shaping of the fins ensures that adhesion forces are minimized from the outset, preventing collapse in subsequent processing steps without requiring additional complexity-reducing steps later in the manufacturing process
Data Source
AI summary
A method includes depositing a mask layer over a semiconductor substrate, etching the mask layer to form a patterned mask, wherein a sidewall of the patterned mask includes a first sidewall region, a second sidewall region, and a third sidewall region, wherein the first sidewall region is farther from the semiconductor substrate than the second sidewall region and the second sidewall region is farther from the semiconductor substrate than the third sidewall region, wherein the second sidewall region protrudes laterally from the first sidewall region and from the third sidewall region, etching the semiconductor substrate using the patterned mask to form fins, forming a gate stack over the fins, and forming source and drain regions in the fin adjacent the gate stack.