Chemically Amplified Resist Composition for High-Resolution E-Beam Patterning
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Solution Overview
Problem
Current resist compositions face challenges in achieving high sensitivity, resolution, and minimal edge roughness due to increased accelerating voltage in electron beam exposure systems, which leads to reduced sensitivity and increased acid diffusion, affecting the formation of fine patterns in microelectronic devices.
Innovation Solution
A chemically amplified resist composition using a polymer with recurring units containing a succinimide structure and a group capable of polarity switching with acid, which effectively suppresses acid diffusion and enhances dissolution contrast, resulting in high sensitivity and resolution with minimal edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the accelerating voltage of the electron beam is increased to improve resolution and reduce forward scattering, then the resolution and dimensional control are improved, but the sensitivity of the resist film decreases
Solution Approach 1:
The patent changes the chemical parameters of the resist composition by incorporating specific basic compounds (amines with pKa 3-10) that modify the acid-base chemistry of the system. This allows the resist to maintain high sensitivity even at 50-100 kV electron beam accelerating voltages where conventional resists would show reduced sensitivity due to decreased ionization efficiency.
Solution Approach 2:
The patent creates a composite resist system combining polyhydroxystyrene polymer matrix with specifically selected basic compound additives. This composite approach allows the resist to simultaneously achieve high resolution (from reduced forward scattering at high voltage) and high sensitivity (from enhanced acid generation efficiency via the basic compounds).
2Productivity
If chemically amplified resist compositions are used to improve sensitivity, then the sensitivity and contrast are enhanced, but acid diffusion increases causing image blur and reduced resolution
Solution Approach 1:
The patent modifies the chemical parameters by selecting basic compounds with specific pKa values (3-10) that optimize the balance between acid generation and acid diffusion. The post-exposure bake conditions are also optimized (90-110°C for 60-120 seconds) to control the diffusion distance while maintaining sufficient deprotection reaction.
Solution Approach 2:
The patent creates local quality differences by using the basic compounds to generate acid locally at the exposed regions. The acid then diffuses a controlled distance to catalyze deprotection, creating a gradient effect that maintains high contrast while achieving sufficient sensitivity enhancement.
3Manufacturing precision
If the temperature and time of post-exposure bake are reduced to suppress acid diffusion, then the resolution is improved, but the sensitivity and contrast are drastically reduced
Solution Approach 1:
The patent changes the thermal parameters by optimizing the post-exposure bake temperature (90-110°C) and time (60-120 seconds) to achieve the right balance. The presence of basic compounds with appropriate pKa values enables sufficient deprotection reaction at these moderate temperatures, maintaining sensitivity while limiting acid diffusion to achieve high 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 resist composition achieves high sensitivity, full suppression of acid diffusion, and improved pattern profiles with minimal edge roughness, making it suitable for manufacturing VLSIs and photomasks with enhanced process adaptability and resolution.
Implementation Method 1
the electron beam exposure system to increase the accuracy of line width
Implementation Method 2
image blurs due to acid diffusion become a problem
Implementation Method 3
a polymer comprising recurring units having a succinimide structure and recurring units containing a group capable of polarity switch with the aid of acid
Implementation Method 4
recurring units containing a group capable of polarity switch with the aid of acid
Implementation Method 5
deprotection reaction does not take place, or even when deprotection reaction takes place, a slow reaction rate leads to a loss of contrast
Data Source
AI summary
A resist composition is provided comprising a polymer comprising recurring units (a) having a succinimide structure and recurring units (b) containing a group capable of polarity switch with the aid of acid. The resist composition suppresses acid diffusion, exhibits a high resolution, and forms a pattern of satisfactory profile with low edge roughness.