Resist Composition Solvent Optimization for 25 nm Gate Uniformity
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Solution Overview
Problem
Current methods for forming resist patterns in semiconductor production fail to achieve sufficient dimensional uniformity, particularly with gate dimensions shrinking to 25 nm and beyond, as existing techniques cannot consistently control the dimensional uniformity of resist patterns during photolithography processes.
Innovation Solution
A pattern forming method involving a resist composition with a solid content concentration of 1.0 to 10.0 mass%, coated at rotational speeds of 500 to 1,500 rpm, and exposed to light with wavelengths between 150 to 250 nm, using a compound that generates acid upon irradiation, a resin with increased alkali developer solubility, and a mixed solvent comprising propylene glycol monoalkyl ether carboxylates, propylene glycol monoalkyl ethers, and γ-butyrolactone, along with a surfactant for improved film thickness and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography processes are used with standard resist compositions, then the basic pattern formation can be achieved, but the dimensional uniformity of the resist pattern cannot meet the required 2.2 nm 3-sigma control for 25 nm gate dimensions
Solution Approach 1:
The patent applies parameter changes by optimizing the solvent composition (specific ratios of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and γ-butyrolactone), solid content concentration (1.0-10.0 mass%), and coating conditions (rotational speed 500-1,500 rpm) to achieve uniform film thickness and excellent dimensional uniformity of resist patterns, enabling consistent dimensional control at 25 nm gate dimensions
Solution Approach 2:
The patent uses a composite resist composition comprising multiple solvent components (propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and γ-butyrolactone), a photoacid generator, and a resin that becomes soluble in alkali developer by acid action. This composite formulation works synergistically to produce resist patterns with superior dimensional uniformity and consistency
2Productivity
If the gate dimension is reduced to 25 nm to increase integration density, then the productivity and capacity are improved, but the dimensional variation increases beyond the acceptable 2.2 nm 3-sigma limit
Solution Approach 1:
The patent achieves both high integration density and precise dimensional control by optimizing resist composition parameters (solvent ratios, solid content 1.0-10.0 mass%) and processing parameters (coating rotational speed 500-1,500 rpm, baking temperature and time), enabling consistent patterning at 25 nm gate dimensions with 2.2 nm 3-sigma variation
3Length of stationary object
If the rotational speed is increased to reduce film thickness to the 50-200 nm range, then the resolution for fine patterns is improved, but the coating uniformity and film quality may deteriorate
Solution Approach 1:
The patent achieves both reduced film thickness (50-200 nm) and high coating uniformity by optimizing the coating rotational speed (500-1,500 rpm) in conjunction with specific resist composition parameters, including solvent composition and solid content concentration (1.0-10.0 mass%), ensuring uniform film formation at the required thickness range for fine pattern resolution
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 method achieves a uniform resist film with excellent dimensional uniformity, enhancing the masking effect and preventing defects during substrate etching, while maintaining a suitable film thickness for effective pattern formation.
Implementation Method 1
a compound capable of generating an acid upon irradiation with one of actinic rays and radiation
Implementation Method 2
coating a resist composition having a solid content concentration of 1.0 to 10.0 mass% on a substrate; adjusting the rotational speed of the substrate within the range of 500 to 1,500 rpm to adjust the film thickness
Implementation Method 3
the wafer is applied with a developer to remove the chemically changed photoresist layer (or chemically unchanged photoresist layer)
Data Source
AI summary
A pattern forming method comprising: coating a resist composition on a substrate; adjusting a rotational speed of the substrate within a range of 500 to 1,500 rpm so that a film thickness of the resist composition coated is adjusted; and subjecting the resist composition to drying, exposure and development, wherein the resist composition includes: (A) a compound capable of generating an acid upon irradiation with one of actinic rays and radiation; (B) a resin of which dissolution rate in an alkali developer increases under the action of an acid; (C) a mixed solvent; and (D) a surfactant, and the mixed solvent (C) includes at least one member selected from a group A of solvents and at least one member selected from a group B of solvents, or includes at least one member selected from the group A of solvents and at least one member selected from a group C of solvents: Group A: propylene glycol monoalkyl ether carboxylates, Group B: propylene glycol monoalkyl ethers, alkyl lactates, acetic acid esters, one of chain and cyclic ketones, and alkoxyalkyl propionates, and Group C: γ-butyrolactone, ethylene carbonate and propylene carbonate.