Silicon Polymer Underlayer for Resist Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current photolithography techniques face challenges in achieving finer patterns due to limitations in wavelength, leading to issues such as pattern collapse and poor adhesiveness between resist layers, especially in advanced node devices like 45 nm and 32 nm-node lithography, where high refractive index immersion lithography and EUV lithography face problems like high power requirements and low transmittance.
Innovation Solution
A silicon-containing polymer and compound are developed, incorporating specific repeating units that form a resist underlayer film with improved adhesiveness and etching selectivity, using a composition that includes a heat/acid leaving group to enhance pattern adhesiveness and prevent collapse in both negative and positive development processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If F2 lithography with 157 nm wavelength is used for finer patterning, then resolution is improved, but etching resistance of resist film decreases and cost increases
Solution Approach 1:
The patent introduces a silicon-containing underlayer film as an intermediary between the resist film and the substrate. This underlayer film has high etching resistance and specific surface properties that enhance adhesiveness to the resist film, thereby compensating for the reduced etching resistance of the resist film when using F2 lithography with 157 nm wavelength.
Solution Approach 2:
The patent modifies the surface properties of the underlayer film by controlling the contact angle through specific chemical groups (carboxyl, hydroxyl, or amine groups). By adjusting the contact angle to 40° or less, the surface wettability is optimized to enhance adhesiveness to the resist film, thereby improving etching resistance without compromising resolution.
2Manufacturing precision
If upper resist layer is made thinner to enable further miniaturization, then patterning precision is improved, but adhesiveness between resist patterns decreases causing pattern collapse
Solution Approach 1:
The silicon-containing underlayer film serves as a mediator between the substrate and the thin upper resist layer. Its specially engineered surface with high adhesiveness provides mechanical support and stabilization to the thin resist patterns, preventing collapse while maintaining patterning precision.
Solution Approach 2:
The patent optimizes the contact angle of the underlayer film surface to 40° or less by incorporating specific chemical groups. This parameter change enhances surface wettability and adhesiveness, providing sufficient mechanical support for thinner resist layers to prevent pattern collapse during processing.
3Productivity
If ArF immersion lithography with water (refractive index 1.44) is used for high speed scanning, then productivity is improved, but wavelength cannot be shortened further for finer patterning
Solution Approach 1:
The patent changes the refractive index parameter by using a liquid immersion medium with higher refractive index than water. This allows further shortening of the effective wavelength for finer patterning while maintaining the immersion lithography configuration that enables high-speed scanning.
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 silicon-containing polymer and compound improve pattern adhesiveness and prevent collapse in fine patterns, enabling stable patterning properties in both negative and positive development processes, and provide high etching selectivity, facilitating precise pattern transfer to substrates even with thinned upper resist layers.
Implementation Method 1
A silicon-containing polymer with specific repeating units that act as heat/acid leaving groups, enhancing adhesiveness by generating reactive species
Implementation Method 2
A silicon-containing polymer with specific repeating units that act as heat/acid leaving groups, enhancing adhesiveness by generating reactive species
Data Source
AI summary
The present invention provides a silicon-containing polymer which contains a repeating unit shown by the general formula (1-3) and one or more repeating units selected from repeating units shown by the general formulae (1-1) and (1-2) as a partial structure. There can be provided a composition for forming a silicon-containing resist under layer film, and a silicon-containing polymer and a silicon-containing compound to give the composition that is capable of forming a resist under layer film improved in adhesiveness in any resist pattern, regardless of negative development or positive development.