EUV Photoresist Underlayer with Sn In Dopants
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Solution Overview
Problem
Current EUV lithography methods require high doses of photoresist exposure due to low EUV photon flux and long exposure times, leading to inadequate contrast between exposed and unexposed areas in photoresist patterns.
Innovation Solution
The introduction of EUV photoresist underlayers with Sn and/or In dopants, specifically Sn(0) and In(0), which reduce the required exposure dose by 5% or more while maintaining excellent roughness, achieved through a layer deposition process involving a reactor chamber, precursor adsorption, and plasma exposure with H2 and a noble gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional photoresist is used in EUV lithography, then the process can be performed with standard materials, but the required exposure dose is high due to low EUV photon flux
Solution Approach 1:
An underlayer comprising Sn and/or In dopants is introduced as an intermediary between the substrate and the photoresist. This underlayer mediates the EUV photon interaction by enhancing the contrast between exposed and unexposed areas, thereby reducing the required exposure dose and exposure time while maintaining effective pattern transfer.
Solution Approach 2:
The chemical composition of the underlayer is modified by incorporating Sn and/or In dopants, which change the optical parameters of the structure. These dopants alter the absorption and scattering characteristics of EUV photons, improving the overall efficiency of the lithography process and reducing the exposure dose requirement.
2Loss of time
If EUV exposure dose is reduced, then exposure time can be decreased, but pattern contrast between exposed and unexposed areas may become inadequate
Solution Approach 1:
The underlayer with Sn and/or In dopants serves as a mediator that enhances the contrast mechanism. It amplifies the difference in optical properties between exposed and unexposed photoresist regions, ensuring that even at reduced exposure doses, sufficient pattern contrast is achieved for accurate pattern transfer.
Solution Approach 2:
The structure becomes a composite system combining the underlayer material with Sn/In dopants and the photoresist layer. This composite structure provides synergistic effects where the underlayer's enhanced optical properties complement the photoresist's patterning function, maintaining high contrast at lower doses.
3Quantity of substance
If Sn and In dopants are added to EUV photoresist underlayer, then exposure dose requirement is reduced by 5% or more, but the process complexity increases
Solution Approach 1:
The composition of the underlayer is optimized by controlling the concentration and type of Sn and In dopants. By adjusting these parameters within specific ranges, the exposure dose is reduced while the deposition process remains manageable through established thin-film fabrication techniques.
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
The use of Sn and In dopants in EUV photoresist underlayers significantly reduces the exposure dose needed for EUV lithography, enhancing pattern formation efficiency and maintaining surface roughness.
Implementation Method 1
providing a precursor comprising Sn and/or In to said reactor chamber thereby adsorbing said precursor on the surface of said substrate
Implementation Method 2
forming an EUV photoresist underlayer on the surface of the substrate within the reaction chamber by exposing the precursor adsorbed on the surface to a plasma
Implementation Method 3
forming an EUV photoresist underlayer on the surface of the substrate within the reaction chamber by exposing the precursor adsorbed on the surface to a plasma
Data Source
AI summary
The disclosure generally relates to the field of semiconductor substrate processing technology, and more particularly to methods for depositing layers of materials on substrates, to structures formed accordingly, and for systems for executing such methods and for forming such structures. Aspects relate to a layer deposition process comprising the steps of forming an extreme ultraviolet (EUV) photoresist underlayer on a surface of a substrate; providing a substrate within a reactor chamber; providing a precursor comprising Sn and/or In to the reactor chamber thereby adsorbing the precursor on the surface of the substrate; and forming an EUV photoresist underlayer on the surface of the substrate within the reactor chamber by exposing the precursor adsorbed on the surface to a plasma, wherein the plasma comprises H2 as reactant and a noble gas as carrier gas.