Semiconductor Contact Hole Formation Using Segmented Etching
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Solution Overview
Problem
The manufacturing of three-dimensional semiconductor memory devices involves a large number of steps for forming contact holes with various depths, leading to increased costs and manufacturing complexity.
Innovation Solution
A method of forming N2 contact holes with N kinds of depths, where N is an integer of three or more, using a two-step process involving lithography and RIE (Reactive Ion Etching) with resist and organic film slimming to achieve N2 kinds of depths, reducing the number of steps required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple lithography and RIE steps are performed to form contact holes with various depths, then contact holes with different depths can be formed, but the number of manufacturing steps increases
Solution Approach 1:
The patent segments the contact hole formation process into two independent stages: (1) forming all contact holes with a first RIE process to achieve various depths, and (2) performing a second RIE process to further etch only the shallow contact holes. This segmentation allows different depth requirements to be met without requiring multiple lithography steps for each depth level, thereby reducing overall process complexity while maintaining manufacturing precision.
Solution Approach 2:
The patent applies preliminary action by forming all contact holes to their maximum required depths in the first RIE process before performing any selective etching. This preliminary formation of deep holes allows subsequent selective removal of material from shallow holes without affecting the deep ones, enabling efficient depth differentiation with minimal additional steps.
2Manufacturing precision
If multiple lithography and RIE steps are performed to form contact holes with various depths, then contact holes with different depths can be formed, but manufacturing cost increases
Solution Approach 1:
The patent segments the contact hole formation process into two independent stages: (1) forming all contact holes with a first RIE process to achieve various depths, and (2) performing a second RIE process to further etch only the shallow contact holes. This segmentation allows different depth requirements to be met without requiring multiple lithography steps for each depth level, thereby reducing overall process complexity while maintaining manufacturing precision.
Solution Approach 2:
The patent uses a universal first RIE process that forms all contact holes to various depths simultaneously, serving multiple depth requirements in a single step. This multi-functional approach eliminates the need for separate lithography and etching steps for each depth level, significantly reducing manufacturing cost while maintaining the ability to produce contact holes with different depths as required.
3Manufacturing precision
If multiple lithography and RIE steps are performed to form contact holes with various depths, then contact holes with different depths can be formed, but production time increases
Solution Approach 1:
The patent segments the contact hole formation process into two independent stages: (1) forming all contact holes with a first RIE process to achieve various depths, and (2) performing a second RIE process to further etch only the shallow contact holes. This segmentation allows different depth requirements to be met without requiring multiple lithography steps for each depth level, thereby reducing overall process complexity while maintaining manufacturing precision.
Solution Approach 2:
The patent merges the formation of contact holes with different depth requirements into a single first RIE process, rather than performing separate etching operations for each depth level. This combining of multiple depth-forming operations into one step significantly reduces production time while maintaining the ability to achieve various contact hole depths through subsequent selective etching.
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 efficiently forms contact holes and plugs with multiple depths in a semiconductor device, reducing production costs and labor by simplifying the manufacturing process.
Implementation Method 1
performing a first process of forming N2 holes having N kinds of depths in the stacked body
Implementation Method 2
performing a first process of forming N2 holes having N kinds of depths in the stacked body where N is an integer of three or more. The method further includes performing a second process of processing the N2 holes so as to have N2 kinds of depths
Data Source
AI summary
In one embodiment, a method of manufacturing a semiconductor device includes forming a stacked body that alternately includes a plurality of first films and a plurality of second films on a substrate. The method further includes performing a first process of forming N2 holes having N kinds of depths in the stacked body where N is an integer of three or more. The method further includes performing a second process of processing the N2 holes so as to have N2 kinds of depths after performing the first process.