Spacer-Defined Wafer Features Below Photolithography Critical Dimension
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in achieving critical dimensions smaller than 5 nm due to limitations in photolithographic techniques.
Innovation Solution
A method is developed to form reduced-size features by creating spacer material on the sidewalls of a carbon-containing layer within a cavity, while inhibiting its formation on the bottom surface, thereby defining a smaller opening than initially photolithographically defined.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithographic processes are used to define edges of openings or structures, then the process is manufacturable with current equipment, but the critical dimension cannot be reduced below 5 nm
Solution Approach 1:
The process segments the feature definition into multiple steps: first forming a larger photolithographically-defined opening, then using spacer material deposition on sidewalls to create the final smaller feature. This segmentation allows each step to operate within current equipment capabilities while achieving beyond-current capabilities in the final dimension.
Solution Approach 2:
The spacer material is formed in advance on the sidewalls of the cavity before the final opening is defined. This preliminary action establishes the boundaries of the smaller feature, allowing the final etch to precisely follow the spacer geometry rather than relying on direct photolithographic definition.
2Manufacturing precision
If spacer material is formed on sidewalls to define smaller openings, then features smaller than critical dimension can be created, but spacer material may form on the bottom surface of the cavity
Solution Approach 1:
The spacer material formation process is made selective to different locations: the bottom surface is treated with a carbon-containing layer that inhibits spacer deposition, while sidewalls remain receptive to spacer material. This local differentiation allows spacer formation only where needed on the sidewalls.
Solution Approach 2:
A carbon-containing layer is introduced as an intermediary between the spacer material and the cavity bottom surface. This intermediate layer acts as a barrier that prevents unwanted spacer deposition on the bottom while allowing the spacer to form on the sidewalls, thus controlling the deposition location.
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 allows for the formation of features with smaller lateral dimensions than the critical dimension of the semiconductor process, enabling the creation of advanced semiconductor devices with nanoscale features.
Implementation Method 1
forming spacer material on the sidewalls of the layer including carbon in the cavity with a material forming process
Data Source
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AI summary
A method for forming features on a wafer that includes forming a first opening in a first layer over a layer including carbon and removing material of the layer including carbon through the first opening to form a cavity. The method includes forming spacer material on the sidewalls of the layer including carbon in the cavity with a material forming process, wherein the spacer material is inhibited from forming on the bottom surface portion of the cavity during the material forming process. The formed spacer material formed a spacer that defines a second opening that is has a smaller lateral dimension in a first lateral direction than the first opening.