Stitched Cut Mask Decomposition for Tighter Contact Enclosure Spacing
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Solution Overview
Problem
Current photolithography techniques face challenges in achieving tight contact enclosure spacing rules due to inner corner rounding in cut masks, leading to increased line end consumption and potential electrical resistance issues in semiconductor devices.
Innovation Solution
The use of a stitched, multiple patterned cut mask that decomposes the target pattern into sub-target patterns with overlapping rectangular-shaped openings, allowing for precise control of contact-to-end-of-cut-line spacing without inner corner rounding, enabling tighter contact enclosure spacing rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single cut mask with non-rectangular opening features is used to pattern line-type features, then the target pattern can be formed, but inner corner rounding occurs leading to increased contact enclosure spacing requirements
Solution Approach 1:
The patent divides a single complex cut mask with non-rectangular openings into multiple simpler cut masks, each containing only rectangular opening features. This segmentation eliminates inner corner rounding issues while achieving the same target pattern through sequential application of multiple masks, thereby reducing contact enclosure spacing requirements.
2Volume of moving object
If tighter contact enclosure spacing rules are applied, then chip shrinkage is enabled, but line end consumption increases due to inner corner rounding in traditional cut masks
Solution Approach 1:
By segmenting the cut mask into multiple masks with rectangular openings only, the patent eliminates inner corner rounding that causes line end consumption. This enables tighter contact enclosure spacing and smaller chip size while maintaining precise line end positioning through the sequential patterning process.
3Productivity
If multiple exposures are used to define the target pattern, then feature density can be increased, but the process complexity and number of steps increase
Solution Approach 1:
The patent segments the patterning process into multiple exposures, each using a simpler cut mask with rectangular openings. While this increases the number of process steps, each individual mask is simpler to manufacture and aligns better with photolithography capabilities, ultimately enabling higher feature density that would be impossible with a single complex mask.
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 reduction of contact enclosure spacing while maintaining accurate alignment and electrical performance, facilitating the production of smaller semiconductor devices by eliminating the need for excessive spacing and minimizing line end consumption.
Implementation Method 1
selectively exposing the radiation-sensitive material to a light generated by a light source (such as a DUV or EUV source) to transfer a pattern defined by a mask or reticle
Implementation Method 2
Various process operations, such as etching or ion implantation processes, may then be performed on the underlying layer of material or substrate through the patterned mask layer
Data Source
AI summary
A method involving identifying a pattern for an overall target cut mask to be used in patterning line-type features that includes a target non-rectangular opening feature having an inner, concave corner, decomposing the overall target cut mask pattern into first and second sub-target patterns, wherein the first sub-target pattern comprises a first rectangular-shaped opening feature corresponding to a first portion, but not all, of the target non-rectangular opening feature and the second sub-target pattern comprises a second rectangular-shaped opening feature corresponding to a second portion, but not all, of the target non-rectangular opening feature, the first and second openings overlapping adjacent the inner, concave corner, and generating first and second sets of mask data corresponding to the first and second sub-target patterns, wherein at least one of the first and second sets of mask data is generated based upon an identified contact-to-end-of-cut-line spacing rule.