Etch-Resistant Disilane Copolymers for Photolithography
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Solution Overview
Problem
In photolithographic manufacturing processes, reducing feature sizes leads to challenges in controlling critical dimensions due to light reflection from layers, necessitating an antireflective material with suitable etch selectivity that is often limited by its similarity to photoresist properties.
Innovation Solution
Development of etch-resistant disilane and saturated hydrocarbon bridged silicon-containing polymers, specifically disilane and hydrocarbon bridge siloxane copolymers with a silylhydride moiety and chromophore, which serve as antireflective coatings and exhibit selective etchability with respect to organic photoresists.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are reduced in photolithographic processes, then device performance and economic savings are improved, but control over critical dimensions deteriorates due to light reflection from layers
Solution Approach 1:
An antireflective coating layer is introduced as an intermediary material between the substrate and the photoresist. This coating has specific optical properties (refractive index and absorption coefficient) that reduce light reflection and standing wave effects, thereby improving the precision of photolithographic patterning at reduced feature sizes
Solution Approach 2:
The patent modifies the chemical composition and molecular structure of the antireflective coating materials, specifically using disilane and saturated hydrocarbon bridged silicon-containing polymers with controlled silylhydride content and chromophore groups. These parameter changes optimize the balance between etch resistance and antireflective performance
2Measurement precision
If an antireflective material is employed under the photoresist, then light reflection is reduced and exposure precision is improved, but etch selectivity deteriorates because many such materials exhibit properties similar to photoresist
Solution Approach 1:
The patent creates a material with spatially differentiated properties by incorporating specific functional groups at controlled concentrations. The disilane units provide etch resistance, while chromophore groups provide antireflective properties. This local quality differentiation within the polymer structure enables simultaneous optimization of both etch selectivity and antireflective performance
Solution Approach 2:
The antireflective coating is designed as a composite polymer system combining multiple monomeric units with distinct functions: disilane units for etch resistance, chromophore-containing units for optical properties, and saturated hydrocarbon bridged units for structural stability. This composite approach enables independent optimization of etch selectivity and antireflective characteristics
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 copolymers provide enhanced precision in photolithographic processes by reducing light reflection and allowing controlled etching, maintaining product yields while enabling smaller feature sizes with improved etch resistance and stability.
Implementation Method 1
a feature formed using a photolithographic process may not be formed with a satisfactory amount of control over critical dimensions as the size of the feature is reduced. In particular, light used to expose a photoresist formed on a layer may reflect from the layer and/or layer interfaces
Implementation Method 2
Such a material may need to exhibit not only antireflective properties, but a suitable etch selectivity with respect to the photoresist as well
Data Source
AI summary
A composition includes a copolymer including a mixture of monomeric units having structures (A), (B), and (C), and one or more of structures (D) or (E):HSiO(3-a)/2(OH)a (A)Si(3-b)/2(OH)b—CH2)n—SiO(3-c)/2(OH)c (B)R1SiO(3-d)/2(OH)d (C)MeSi(3-e)/2(OH)e (D)R2SiO(3-f)/2(OH)f (E)wherein a, b, c, d, e, and f are independently from 0 to 2, n is from 0 to about 10, R1 is a chromophore, and R2 is a hydrophilic group.