Trench Portion Blocking via Selective Etching
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Solution Overview
Problem
In semiconductor device manufacturing, particularly at advanced nodes, the challenge is to pattern trench interruptions without increasing the number of layers in the hard mask stack, which becomes impractical when multiple lithographic masks are used, leading to difficulties in alignment and electrical shorting risks.
Innovation Solution
A method involving a hard mask stack with a first coating that can be selectively etched, where a vertical via is etched to block trench portions, creating two new trenches with well-defined dimensions, allowing for precise control of spacing and reducing the risk of electrical shorting without increasing the hard mask stack layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple lithographic masks are used to define trench interruptions, then the patterning precision of trench portions is improved, but the number of layers in the hard mask stack increases making alignment difficult
Solution Approach 1:
The patent segments the hard mask stack into functionally distinct layers: a first hard mask layer for defining trenches and a second hard mask layer for defining interruptions. This segmentation allows each layer to be optimized for its specific function and enables independent patterning processes, resolving the contradiction by maintaining multiple patterning capabilities while organizing the stack to manage complexity through clear functional separation and selective etching processes.
2Manufacturing precision
If multiple lithographic masks are used to define trench interruptions, then the patterning completeness is improved, but the alignment difficulty increases due to inability to identify common reference layer
Solution Approach 1:
The patent introduces an intermediary etch-stop layer positioned between the first and second hard mask layers. This intermediary layer serves as a stable reference that can be detected during alignment processes, enabling accurate registration between multiple lithographic masks. The etch-stop layer acts as a mediator that provides a common reference point for alignment while allowing the multi-layer stack to maintain its functional separation for complete trench interruption definition.
3Ease of manufacture
If conventional trench blocking methods are used, then the process simplicity is maintained, but the electrical shorting risk increases due to poor spacing control
Solution Approach 1:
The patent changes the critical parameter for spacing control from lithographic overlay accuracy to via hole diameter, which can be precisely controlled through etch process parameters. By defining the blocked portion dimensions through the via hole size rather than through complex multi-layer overlay, the method maintains relative process simplicity while significantly improving spacing control accuracy and reducing electrical shorting risk between adjacent trenches.
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 method enables accurate blocking of trench portions, reducing the risk of electrical shorting and maintaining a stable hard mask stack, allowing for efficient formation of connecting lines in semiconductor devices without increasing the number of layers, thus improving manufacturing efficiency.
Implementation Method 1
the first coating comprises one or more materials that can be etched selectively with respect to a second coating
Data Source
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AI summary
A method for blocking a portion of a longitudinal through-hole during manufacture of a semiconductor structure, comprising the steps of: - forming a stack comprising: o A hard mask (5) comprising at least one trench, and o A first coating (11) filling the at least one trench and coating the hard mask, wherein the first coating comprises one or more materials that can be etched selectively with respect to a second coating, - Etching at least one vertical via in said first coating directly above said portion of the trench in such a way as to remove the first coating over at least a fraction of the depth of the trench, - Filling the at least one via with the second coating material (16), - Removing the first coating selectively with respect to the second coating from at least the one or more longitudinal through-holes in such a way as to leave in place any of the first coating present directly underneath the second coating.