Semiconductor Fin Patterning via Oxidizable Masking
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Solution Overview
Problem
Existing methods for forming semiconductor fin structures using spacers often result in increased spacing between fin structures due to height-to-width ratio parameters, limiting the density of transistors per die area.
Innovation Solution
A process involving the oxidation of an oxidizable material layer to form oxide masks, which are then used to pattern and define semiconductor fin structures, allowing for closer spacing between fins by controlling the growth of oxide layers and selective etching to pattern the underlying layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spacers are used to define semiconductor fin structures, then fin width can be reduced below lithographic critical dimension, but the distance between fin structures increases beyond desired spacing
Solution Approach 1:
An oxidizable material layer is introduced as an intermediary between the spacer and the fin structure. This layer is selectively oxidized to form oxide masks that define the fin structures. The oxidizable material acts as a mediator that allows precise fin width control through oxidation while maintaining desired spacing between fins, resolving the contradiction between fine feature control and spacing requirements
Solution Approach 2:
The invention changes the physical and chemical parameters of the patterning process by introducing oxidation as a key step. The oxidizable material layer undergoes chemical transformation when exposed to oxidizing conditions, forming oxide masks with specific properties. This parameter change enables independent control of fin width (through oxidation extent) and fin spacing (through original layer spacing), resolving the trade-off in traditional spacer-based patterning
2Manufacturing precision
If first fin structures are formed to create spacers, then sub-lithographic fin width is achieved, but transistor density per die area decreases
Solution Approach 1:
The oxidizable material layer serves as an intermediary that enables sub-lithographic patterning without requiring large spacer distances. By using oxidation to define fin boundaries, the method achieves fine feature sizes while maintaining compact layouts, thereby increasing transistor density while still achieving sub-critical-dimension fin widths
Solution Approach 2:
The invention adds a chemical dimension (oxidation state) to the patterning process. Instead of relying solely on physical spacer dimensions, the fin width is controlled through the extent of oxidation of the intermediary layer. This dimensional addition enables independent optimization of both fin width and spacing, maximizing transistor density
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
This approach enables the formation of semiconductor fin structures with spacings less than the critical dimension of the lithographic process, allowing for a higher density of fins per unit area and improved transistor performance.
Implementation Method 1
oxidizing sidewalls of the oxidizable layer to form oxide masks
Data Source
AI summary
Forming structures such as fins in a semiconductor layer according to a pattern formed by oxidizing a sidewall of a layer of oxidizable material. In one embodiment, source/drain pattern structures and a fin pattern structures are patterned in the oxidizable layer. The fin pattern structure is then masked from an oxidation process that grows oxide on the sidewalls of the channel pattern structure and the top surface of the source/drain pattern structures. The remaining oxidizable material of the channel pattern structure is subsequently removed leaving a hole between two portions of the oxide layer. These two portions are used in one embodiment as a mask for patterning the semiconductor layer to form two fins. This patterning also leaves the source/drain structures connected to the fins.