Peripheral Opening Layout for Uniform Plasma Etching
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Solution Overview
Problem
In the manufacturing of three-dimensional stacked semiconductor memories, there is a discrepancy in the shape of openings formed in the etching target film, particularly between the central and peripheral portions, due to uneven etching rates caused by the incident angle of ions during plasma etching, leading to shallower openings at the peripheral regions.
Innovation Solution
A substrate structure is implemented with a first film, such as an amorphous carbon layer, having multiple openings with a specific layout and a second opening outside these, where the second opening has a larger width but smaller depth, ensuring uniform etching progress across the substrate by maintaining a consistent etching rate and preventing the second opening from reaching the etching target film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching is performed to form openings in the etching target film, then openings are formed in the film, but the etching rate becomes uneven between central and peripheral portions due to ion incident angle variations
Solution Approach 1:
The patent applies local quality by creating different opening configurations in different regions of the first film. Specifically, multiple first openings are formed in the central region with a first pitch, while a second opening is formed in the peripheral region with a second pitch that is 0.5 to 2.0 times the first pitch. This local variation in opening spacing compensates for the uneven etching rates caused by ion incident angle differences between central and peripheral regions during plasma etching, thereby achieving uniform opening shapes across the entire substrate.
2Quantity of substance
If the first film has multiple openings with small pitch to increase density, then the etching uniformity across the substrate deteriorates due to peripheral regions being further from the center
Solution Approach 1:
The patent implements local quality by differentiating the pitch between central and peripheral openings. The multiple first openings in the central region are spaced at a first pitch, while the second opening in the peripheral region is spaced at a second pitch that is 0.5 to 2.0 times larger. This approach allows high-density opening formation in the central region while maintaining etching uniformity across the entire substrate by adjusting peripheral opening spacing to compensate for the increased distance from the etching source.
3Manufacturing precision
If the second opening has larger width to improve etching uniformity, then the depth of the second opening becomes smaller
Solution Approach 1:
The patent applies local quality by creating openings with different dimensions in different regions. The first openings in the central region have a first width and first depth, while the second opening in the peripheral region has a second width that is 0.5 to 2.0 times the first width and a second depth that is 0.5 to 2.0 times the first depth. This dimensional adjustment in the peripheral region compensates for the reduced ion flux and slower etching rate at greater distances from the substrate center, thereby achieving uniform etching depth and shape across the entire substrate.
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 effectively suppresses the discrepancy in opening shapes by ensuring consistent etching across the substrate, maintaining the integrity of the etching target film and preventing the formation of additional openings in the target film, thus enhancing the manufacturing process for three-dimensional stacked semiconductor memories.
Implementation Method 1
there is performed a process of forming holes having a high aspect ratio densely in a stacked film which is composed of a multiple number of insulating films stacked on top of each other
Implementation Method 2
due to uneven etching rates caused by the incident angle of ions during plasma etching
Data Source
AI summary
A substrate includes an etching target film as a target of etching and a first film. The first film is formed on the etching target film and is made of a material having an etching rate smaller than an etching rate of the etching target film. The first film has multiple first openings formed at a first distance therebetween in one direction of a surface of the first film. The first film has a second opening formed at an outside of the multiple first openings in the one direction while being spaced apart from an outermost one of the first openings by a second distance equivalent to the first distance. The second opening has a width larger than a width of the first openings and a depth smaller than a depth of the first openings.