Pitch Doubling Pattern Formation on Substrates
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Solution Overview
Problem
Photolithography techniques face limitations in reducing feature size due to minimum pitch constraints, making it challenging to form smaller and denser integrated circuitry, and there is a need for methods to achieve uniformity in feature dimensions.
Innovation Solution
The method involves pitch doubling and pitch multiplication techniques by depositing spacer-forming layers, anisotropically etching them to form sub-lithographic features, and using fill materials to create patterns that allow for feature size reduction and uniformity, including the formation of contact openings to node locations in integrated circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If photolithography techniques are used to form patterns, then manufacturing process is well-established and reliable, but minimum pitch limits feature size reduction
Solution Approach 1:
The pitch doubling process segments the pattern formation into distinct stages: first forming mandrels at relaxed pitch, then creating spacers around mandrels to achieve sub-lithographic features. This segmentation allows each stage to be optimized independently, overcoming the minimum pitch limitation while maintaining manufacturing precision.
Solution Approach 2:
The method performs preliminary actions by first forming mandrels and spacers before final pattern transfer. The spacers are formed as preliminary structures that define the final feature locations and dimensions, enabling precise feature formation beyond photolithography limits.
2Length of moving object
If pitch doubling techniques are used to reduce feature size, then minimum pitch limitation is overcome, but process complexity increases
Solution Approach 1:
The spacer formation process is self-aligned, where spacers automatically position themselves relative to mandrels through conformal deposition. This self-service mechanism eliminates the need for additional alignment steps and complex lithography processes, reducing overall process complexity despite multiple deposition and etch steps.
Solution Approach 2:
The method merges multiple functions into unified process steps: spacer deposition simultaneously forms protective layers and defines feature dimensions, while anisotropic etching both removes mandrels and transfers patterns. This merging reduces the total number of separate process steps required.
3Manufacturing precision
If conventional photolithography is used, then process is simple and well-established, but feature uniformity deteriorates at small dimensions
Solution Approach 1:
The method replaces mechanical photolithographic patterning with vapor-phase deposition and anisotropic etching processes. The spacer thickness, controlled by atomic layer deposition, provides precise and uniform feature dimensions that are less sensitive to optical limitations and more consistent at small feature sizes.
4Productivity
If feature size is reduced to increase circuit density, then productivity improves, but manufacturing precision requirements increase
Solution Approach 1:
The method changes the controlling parameter for feature dimension from photolithographic wavelength to spacer layer thickness. By controlling deposition thickness at the nanometer scale through atomic layer deposition, the process achieves superior dimensional control and uniformity, enabling higher circuit density with maintained precision.
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 smaller and more uniform features beyond the limitations of conventional photolithography, allowing for the creation of denser integrated circuitry with precise pattern formation and contact openings.
Implementation Method 1
The spacer-forming layers are commonly anisotropically etched to form sub-lithographic features
Data Source
AI summary
A method of forming a pattern on a substrate includes forming a repeating pattern of four first lines elevationally over an underlying substrate. A repeating pattern of four second lines is formed elevationally over and crossing the repeating pattern of four first lines. First alternating of the four second lines are removed from being received over the first lines. After the first alternating of the four second lines have been removed, elevationally exposed portions of alternating of the four first lines are removed to the underlying substrate using a remaining second alternating of the four second lines as a mask. Additional embodiments are disclosed and contemplated.