Fin Structure Verticality via Mandrel Segmentation
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Solution Overview
Problem
Conventional etching techniques fail to produce defect-free FinFET devices with sufficient verticality at advanced technology nodes, resulting in slanted sidewalls and occluded trenches due to inadequate spacer pattern transfer to the hardmask.
Innovation Solution
A substrate processing method involving the formation of patterned hardmask and mandrel structures, followed by deposition and removal of gap fill materials to create second mandrel structures, which are used as masks for forming fin structures, allowing for improved verticality and reduced lateral growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If thick spacers are utilized to pattern an underlying hardmask, then bending or leaning of the patterned spacer is reduced, but less than desirable verticality of the hardmask persists resulting in slanted sidewalls
Solution Approach 1:
The process is divided into multiple sequential steps: forming first mandrels, depositing gap fill material, removing first mandrels, forming second mandrels, and finally forming fins. This segmentation allows each step to independently contribute to the final verticality without compounding errors from previous steps.
Solution Approach 2:
The first mandrels are formed in advance to provide a foundation for gap fill material deposition. This preliminary structure enables subsequent steps to achieve better verticality by building upon a pre-established framework rather than attempting to achieve verticality in a single step.
2Ease of manufacture
If conventional etching techniques are used, then fabrication process is simpler, but defect free FinFET devices with sufficient verticality cannot be achieved at advanced technology nodes
Solution Approach 1:
Multiple intermediary structures (first mandrels, gap fill material, second mandrels) are introduced as mediators between the initial spacer pattern and the final fin structure. These intermediaries enable precise control of fin verticality and shape that cannot be achieved through conventional direct etching alone.
3Measurement precision
If spacer pattern is transferred to hardmask, then pattern definition is achieved, but inadequate verticality transfer results in slanted sidewalls
Solution Approach 1:
The process transitions from two-dimensional spacer patterning to three-dimensional fin structure formation through multiple sequential steps. The introduction of vertical mandrel structures and gap fill material adds dimensional control, enabling independent optimization of pattern definition and sidewall verticality.
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 method achieves enhanced verticality and reduced edge roughness of fin structures, improving the fabrication of semiconductor devices by controlling sidewall growth and maintaining verticality profiles.
Implementation Method 1
A flowable oxide gap fill material is deposited on the hardmask material and the III-V material first mandrel structures
Implementation Method 2
III-V material first mandrel structures are formed on exposed region of the substrate. The III-V material first mandrel structures extend a first distance of greater than about 80 nm above a top surface of the substrate
Data Source
AI summary
Embodiments described herein relate to substrate processing methods. The methods include forming a patterned hardmask material on a substrate, forming first mandrel structures on exposed regions of the substrate, and depositing a gap fill material on the substrate over the hardmask material and the first mandrel structures. The first mandrel structures are removed to expose second region of the substrate form second mandrel structures comprising the hardmask material and the gap fill material and fin structures are deposited on the substrate using the second mandrel structures as a mask.