Semiconductor Contact Structure With Dielectric Isolation Trench
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Solution Overview
Problem
As feature sizes in semiconductor devices continue to decrease, the complexity of fabrication processes increases, making it challenging to form reliable semiconductor devices at smaller scales.
Innovation Solution
The process involves forming a nanostructure stack over a substrate with a fin structure, creating gate stacks and source/drain structures, and then removing portions to form trenches and dielectric isolation structures, which helps in reducing contact resistance and improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency is improved and costs are lowered, but fabrication process complexity increases and manufacturing difficulty increases
Solution Approach 1:
The fabrication process is divided into multiple sequential patterning steps (first pattern layer, second pattern layer, third pattern layer) with each step creating specific features. This segmentation allows complex 3D structures to be built through simpler, repeated processes rather than attempting to create all features in a single step, thereby managing fabrication complexity while achieving high functional density
Solution Approach 2:
The patent transitions from 2D planar structures to 3D vertical structures by forming pattern layers at different heights and depths (e.g., first pattern layer at first depth, second pattern layer at second depth). This dimensional transition enables increased functional density without proportionally increasing fabrication process complexity, as the same patterning techniques are applied across multiple layers
2Area of stationary object
If feature sizes continue to decrease to increase functional density, then chip area is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent forms mandrel structures and spacer structures before final pattern definition. These preliminary structures serve as templates that guide subsequent patterning steps, ensuring precise feature dimensions are achieved through self-aligned processes rather than relying solely on lithographic precision at each step
Solution Approach 2:
The fabrication process employs self-aligned patterning where previously formed structures (mandrels, spacers) automatically define the positions of subsequent features. This self-service mechanism eliminates the need for additional alignment precision beyond what is already achieved in earlier steps, maintaining manufacturing precision while reducing chip area
Data Source
AI summary
A method for forming a semiconductor device structure is provided. The method includes providing a substrate and a nanostructure stack. The method includes forming a first gate stack and a second gate stack wrapped around the nanostructure stack. The method includes forming a first source/drain structure in the nanostructure stack and between the first gate stack and the second gate stack. The method includes removing the second gate stack, the nanostructure stack and the fin under the second gate stack to form a trench passing through the nanostructure stack and the fin. The method includes forming a dielectric isolation structure in the trench. The method includes removing the first gate stack and the first nanostructure. The method includes forming a third gate stack wrapped around the second nanostructure. The method includes forming a first contact structure over the first source/drain structure.