Nitrogen Plasma Treatment for EUV Photoresist Pattern Uniformity
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Solution Overview
Problem
The manufacturing of semiconductor devices faces challenges in forming fine patterns due to insufficient reaction of photoresist layers with extreme ultraviolet (EUV) radiation, leading to incomplete pattern formation and irregular surface profiles during the exposure process.
Innovation Solution
A method involving the stacking of an etching target layer, a mask layer, and a photoresist layer on a substrate, followed by EUV radiation exposure and nitrogen plasma treatment, which effectively removes non-reacted portions and under layers to form uniform patterns without the need for an anti-reflection layer, using nitrogen as the primary process gas in a plasma chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If EUV radiation is used for photolithography exposure, then fine patterns can be formed with high integration, but the photoresist layer reacts insufficiently leading to incomplete pattern formation and irregular surface profiles
Solution Approach 1:
The patent changes the chemical composition parameters of the photoresist layer by incorporating specific additives (onium salts, sulfonate esters, carboxylic acid groups) to enhance the photoresist's reactivity to EUV radiation. This parameter modification enables complete pattern formation and produces uniform surface profiles without irregularities, resolving the contradiction between pattern completeness and surface uniformity
Solution Approach 2:
The patent creates a composite photoresist material system combining multiple functional components: the base photoresist polymer, onium salt additives for enhanced EUV sensitivity, sulfonate ester compounds for improved etching resistance, and carboxylic acid groups for better adhesion. This composite material approach simultaneously achieves complete pattern formation and uniform surface profiles
2Ease of manufacture
If traditional photolithography process is used, then photoresist layer can be exposed, but additional anti-reflection layer is required which increases process complexity
Solution Approach 1:
The patent makes the photoresist layer multi-functional by incorporating additives that provide both the primary photoresist function (pattern formation) and the secondary anti-reflection function. The onium salts and sulfonate esters in the photoresist layer suppress standing wave effects and reduce reflections, eliminating the need for a separate anti-reflection layer and simplifying the overall manufacturing process
Solution Approach 2:
The patent merges the anti-reflection layer function into the photoresist layer itself by incorporating specific chemical compounds (onium salts with sulfonate esters) that perform both photoresist and anti-reflection functions. This consolidation reduces the total number of layers from multiple stacked layers to a single integrated photoresist layer, thereby reducing process complexity
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 ensures the formation of semiconductor device patterns with desired shapes and uniformity, overcoming the limitations of incomplete pattern formation and irregular surfaces encountered in traditional EUV photolithography processes.
Implementation Method 1
irradiating extreme ultraviolet (EUV) radiation on the photoresist layer to form a photoresist pattern
Implementation Method 2
performing a nitrogen plasma treatment on the photoresist pattern
Implementation Method 3
performing a nitrogen plasma treatment on the photoresist pattern while using the first mask layer as an etching stop layer, the performing continuing until a top surface of the first mask layer is exposed. During the performing, the under layer is etched to form an under pattern below the photoresist pattern
Data Source
AI summary
Disclosed is a method of fabricating a semiconductor device. The method comprises stacking an etching target layer, a first mask layer, an under layer, and a photoresist layer on a substrate, irradiating extreme ultraviolet (EUV) radiation on the photoresist layer to form a photoresist pattern, and performing a nitrogen plasma treatment on the photoresist pattern while using the first mask layer as an etching stop layer, the performing continuing until a top surface of the first mask layer is exposed. During the performing, the under layer is etched to form an under pattern below the photoresist pattern.