Organotin Cluster Photoresist Stabilization for EUV Lithography
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Solution Overview
Problem
Conventional organotin cluster photoresists suffer from poor stability, solubility, and short shelf life, leading to aggregation and precipitation issues during photolithography, which result in defects and scums on semiconductor substrates, limiting their application in extreme ultraviolet (EUV) lithography for nanoscale feature sizes below 7 nm.
Innovation Solution
The use of organic molecules with functional groups such as —SH, —OH, —NH2, —COOH, and others to stabilize organotin clusters, preventing aggregation and precipitation, and improving solubility, thereby enhancing the stability, shelf life, and uniformity of the photoresists for EUV lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organotin cluster photoresists are used, then high ultraviolet light absorption and photosensitivity are achieved, but poor stability, solubility, and short shelf life result in aggregation and precipitation
Solution Approach 1:
Organic molecules with functional groups (—SH, —OH, —NH2, —COOH, phosphine, phosphine oxide, phosphonic acid) are introduced as intermediary stabilizing agents. These molecules adsorb onto the organotin cluster surface through coordination bonds, forming a protective layer that prevents direct interaction between clusters, thereby preventing aggregation and precipitation while maintaining the clusters' high UV absorption capability
Solution Approach 2:
The patent creates a composite structure where organic stabilizing molecules are combined with organotin clusters. This composite material integrates the high photosensitivity of organotin clusters with the stabilizing properties of organic molecules, achieving both improved stability and maintained photosensitivity in a single photoresist system
2Reliability
If organic additives are added to stabilize organotin clusters, then stability and solubility are improved, but the complexity of the photoresist composition increases
Solution Approach 1:
The organic molecules are designed to perform multiple functions simultaneously: they stabilize the organotin clusters by preventing aggregation, improve solubility in organic solvents, and maintain or enhance photosensitivity. This multi-functionality reduces the need for multiple separate additives, thereby limiting the increase in composition complexity
Solution Approach 2:
The patent optimizes parameters such as the type of functional groups, their concentration, and molecular structure to achieve effective stabilization with minimal additive amounts. By carefully controlling these parameters, the photoresist composition remains relatively simple while still achieving the desired stability and solubility improvements
3Manufacturing precision
If organotin clusters are used for EUV lithography, then high resolution and sensitivity are achieved, but aggregation and precipitation cause defects and scums on substrates
Solution Approach 1:
Organic stabilizing molecules act as intermediaries that form a protective coating around organotin clusters. This coating prevents cluster aggregation and precipitation that would otherwise cause defects and scums on substrates, while allowing the clusters to maintain their high resolution and sensitivity properties during EUV lithography
Solution Approach 2:
The organic additives provide beforehand cushioning by pre-stabilizing the organotin clusters before they are applied to substrates. This preventive stabilization ensures that clusters remain dispersed and stable throughout the photolithography process, preventing the formation of harmful defects and scums that would compromise pattern quality
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 organic molecule-stabilized organotin cluster photoresists exhibit improved resolution, sensitivity, and reduced line width roughness, ensuring high-quality patterning without pattern collapse, with enhanced stability and solubility, enabling efficient EUV lithography for nanoscale features.
Implementation Method 1
The organic additives comprise organic thiol, organic alcohol, organic amine, organic amide, organic carboxylic acid, organic phosphine, organic phosphine oxide, or organic phosphonic acid, which can be adsorbed, grafted, immobilized, anchored, or coordinated on organotin photoresists
Implementation Method 2
Organometallic compounds have high ultraviolet light adsorption because metals have high adsorption capacity of ultraviolet radiation with various carbon-metal (C-M) bond dissociation energy
Implementation Method 3
after exposure, the exposed portion of organic additive-stabilized organotin photoresists convert to polynuclear oxo-hydroxide network or metal oxides with poor solubility in solvents
Data Source
AI summary
The present disclosure is related to organotin cluster photoresists and stabilization methods, particularly for extreme ultraviolet radiation (EUV) photolithography. The organotin cluster photoresists comprise one or more represented by chemical formulas [RR1Sn]3E3, and [RSn]4E6. The stabilization methods include the application of organic molecules as additives to stabilize organotin cluster photoresists.