Pitch Multiplication via Spacer Formation on Substrates
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Solution Overview
Problem
Photolithographic techniques face limitations in reducing feature size due to minimum pitch constraints, which hinder the continued miniaturization of integrated circuitry.
Innovation Solution
The method involves adsorbing a polymer to the outer surfaces of spaced features on a substrate, allowing for selective etching or removal to form patterns, and potentially using pitch multiplication techniques to create features smaller than the minimum photolithographic resolution by depositing spacer-forming materials and anisotropically etching them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography is used to form patterns, then manufacturing process is simple and reliable, but minimum pitch limits further feature size reduction
Solution Approach 1:
The patent segments the patterning process into multiple stages: first forming mandrels at relaxed pitch, then depositing spacer material around mandrels, and finally removing mandrels to leave only spacers. This segmentation allows achieving sub-lithographic pitch by breaking down the single-step lithography into multi-step self-aligned processes
Solution Approach 2:
The patent performs preliminary actions by first depositing spacer-forming material around mandrels before removing the mandrels themselves. This preliminary spacer deposition establishes the final pattern dimensions independently of the original mandrel dimensions, enabling pitch multiplication beyond the lithographic limit
2Manufacturing precision
If pitch multiplication techniques are used to reduce feature size below minimum pitch, then feature size reduction is achieved, but process complexity increases
Solution Approach 1:
The patent merges multiple functions into the spacer-forming material: it serves as both the dimension-defining element and the final pattern material. By combining the spacer function with the pattern formation function, the process achieves pitch multiplication without requiring separate etching and deposition steps for each layer
Solution Approach 2:
The spacer-forming material automatically defines the pattern dimensions through its own deposition thickness, which is controlled by atomic layer deposition precision rather than lithographic resolution. The system serves itself by using the spacer material's intrinsic properties (deposition control, etch selectivity) to define the final pattern without requiring additional alignment or measurement steps
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 patterns with sizes smaller than the minimum photolithographic resolution, overcoming pitch limitations and allowing for further reduction in feature size in semiconductor processing.
Implementation Method 1
adsorbing a polymer to the outer surfaces of spaced features on a substrate
Implementation Method 2
The spacer-forming materials are commonly anisotropically etched to form sub-lithographic features
Data Source
AI summary
A method of forming a pattern on a substrate includes forming spaced features over a substrate. A polymer is adsorbed to outer lateral surfaces of the spaced features. Either material of the spaced features is removed selectively relative to the adsorbed polymer or material of the adsorbed polymer is removed selectively relative to the spaced features to form a pattern on the substrate. In one embodiment, the polymer is of known chain length and has opposing longitudinal ends. One of the longitudinal ends of the polymer adsorbs to the outer lateral surfaces whereby the adsorbed polymer projects lengthwise from the outer lateral surfaces, with said chain length defining a substantially uniform lateral thickness of the adsorbed polymer on the spaced features. Additional embodiments are contemplated.