Quadruple Patterning for Sub-25nm Line Widths
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Solution Overview
Problem
Current photolithography technologies face challenges in reducing line/space width below 25/25 nm without replacing existing machines, which is costly and limits the integration density of non-volatile memory devices.
Innovation Solution
A quadruple patterning method involving multiple transfer patterns and conversion processes, including oxidation and nitridation, to increase pattern density by 4 times and reduce pitch to ¼ of its original length, using existing equipment and materials like polysilicon and metal layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing photolithography machines and processes are used, then manufacturing cost is reduced, but line/space width cannot be reduced below 25/25 nm
Solution Approach 1:
The patent divides the patterning process into multiple stages: forming first transfer patterns, performing first conversion process to create first conversion patterns, filling second transfer patterns in gaps, performing second conversion process to create second conversion patterns, filling third transfer patterns in gaps, and finally forming the target pattern. This multi-stage segmentation enables achieving 25/25 nm or smaller line/space widths using existing photolithography equipment by breaking down the complex patterning task into manageable steps that each existing machine can handle.
2Quantity of substance
If existing photolithography machines are used, then equipment investment is reduced, but pattern density cannot be increased beyond current limits
Solution Approach 1:
The patent introduces temporal dimension to the patterning process by performing multiple conversion processes and fill operations sequentially. The first conversion process transforms first transfer patterns into first conversion patterns, then second transfer patterns are filled in the gaps. Subsequently, the second conversion process transforms these into second conversion patterns, and third transfer patterns are filled in remaining gaps. This multi-temporal approach increases pattern density by 4 times and reduces pitch to 1/4 of original length while using existing equipment.
3Manufacturing precision
If new machines with shorter wavelength light sources are used, then line/space width can be reduced below 25/25 nm, but manufacturing cost increases significantly
Solution Approach 1:
The patent creates multiple copies of patterns through the multi-stage process: first transfer patterns are converted to first conversion patterns, then second transfer patterns are copied into gaps, followed by conversion to second conversion patterns, and finally third transfer patterns are copied into remaining gaps. This copying approach enables achieving 25/25 nm or smaller line/space widths using existing photolithography equipment, avoiding the need for expensive new machines with shorter wavelength light sources while still achieving the required 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
Enables line/space widths of 25/25 nm or smaller with existing machines, significantly increasing pattern density and reducing pitch, thereby reducing costs and improving competitiveness without the need for new equipment or photoresists.
Implementation Method 1
a first conversion process is performed to surfaces of the first transfer patterns, so as to form a plurality of first conversion patterns on the surfaces of the first transfer patterns
Implementation Method 2
the first conversion process and the second conversion process each include an oxidation process, a nitridation process, an oxynitridation process or a metal silicidation process
Implementation Method 3
the step of removing the first conversion patterns and the step of removing the second conversion patterns each include performing an etching process
Implementation Method 4
the step of removing the portion of the first transfer layer includes performing an etching back process or a CMP process
Data Source
AI summary
A patterning method is provided. First, a mask layer and a plurality of first transfer patterns are sequentially formed on a target layer. Thereafter, a plurality of second patterns is formed in the gaps between the first transfer patterns. Afterwards, a plurality of third transfer patterns is formed, wherein each of the third transfer patterns is in a gap between a first transfer pattern and a second transfer pattern adjacent to the first transfer pattern. A portion of the mask layer is then removed, using the first transfer patterns, the second transfer patterns and third transfer patterns as a mask, so as to form a patterned mask layer. Further, a portion of the target layer is removed using the patterned mask layer as a mask.