Semiconductor Patterning With Ion Beam Trimmed Carbon Hard Mask
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Solution Overview
Problem
As semiconductor processes downscale, there is a growing need for more exact patterning layers to reduce edge placement errors and improve the non-uniformity and distribution of line-end critical distances, while also reducing line-end bridge defects.
Innovation Solution
A directional ion beam trimming process is employed in a lithography and etching process to form square shapes in line-end structures, which improves edge placement errors and reduces non-uniformity and distribution of line-end critical distances. This process involves using a carbon-rich material with a carbon content between 50% and 100% by atomic weight, which hardens and reduces the etching rate, allowing for greater control and maintaining critical dimensions within process tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography and etching processes are used for down-scaled semiconductor devices, then manufacturing capability is maintained, but edge placement errors increase and patterning precision deteriorates
Solution Approach 1:
A mandrel structure is formed beforehand, followed by depositing a sacrificial material layer around it. This preliminary configuration enables subsequent precise patterning operations to achieve accurate edge placement and critical dimensions that cannot be obtained through conventional direct lithography alone.
Solution Approach 2:
The mandrel structure serves as an intermediary element that facilitates precise patterning. The sacrificial material layer acts as a mediator that transfers the mandrel's precise geometry to the final pattern, enabling accurate edge placement while the mandrel itself can be removed after serving its patterning function.
2Productivity
If feature density is increased to improve device capacity, then device functionality improves, but line-end bridge defects increase
Solution Approach 1:
The mandrel and sacrificial material layer are formed in advance with precise spacing, creating a template that prevents line-end bridge defects during high-density patterning. This preliminary structure ensures that even as feature density increases, the spacing and alignment are controlled to avoid bridging between adjacent lines.
3Length of moving object
If critical dimensions are reduced to improve device density, then device capacity increases, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The mandrel structure is formed with precisely controlled dimensions before the sacrificial material is deposited. This preliminary definition of critical dimensions through the mandrel provides a physical template that ensures accurate dimensional control, enabling the fabrication of smaller features with high precision that would be difficult to achieve through lithography alone.
Solution Approach 2:
The patent replaces reliance on optical lithography resolution with a mechanical/physical template approach using the mandrel structure. The mandrel's physical dimensions directly define the critical dimensions of the pattern, substituting optical precision requirements with mechanical precision in the mandrel fabrication, which can achieve smaller and more precise dimensions.
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
The directional ion beam trimming process achieves a significant reduction in edge placement errors and line-end bridge defects, with up to a 76% reduction in instances of line-end bridge defects, while improving the non-uniformity and distribution of line-end critical distances.
Implementation Method 1
the directional ion beam trimming process includes hardening the carbon-rich material. The hardening of the carbon-rich material reduces an etching rate in the carbon-rich material
Data Source
AI summary
A method for forming a semiconductor device is provided. In some embodiments, the method includes forming a target layer over a semiconductor substrate, forming a carbon-rich hard masking layer over the target layer, patterning features in the carbon-rich hard masking layer using an etching process, performing a directional ion beam trimming process on the features patterned in the carbon-rich hard masking layer, and patterning the target layer using the carbon-rich hard masking layer as a mask.