Photoresist Cross-Linking for Semiconductor Patterning
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Solution Overview
Problem
In double patterning technology (DPT) processes for semiconductor manufacturing, intermixing between films poses a challenge, particularly in forming precise patterns with sizes of 1 μm or less, where existing methods struggle to control critical dimensions and minimize material dissolution during lithography and spin-on coating processes.
Innovation Solution
A method involving the formation of a photoresist pattern with a leaving group, such as a tertiary butyl group, which undergoes cross-linking and spin-on coating with an oxide layer to create spacers, reducing intermixing by minimizing solvent solubility and controlling pattern width through specific temperature and processing stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography processes are used to form patterns of 1 μm or less, then pattern formation is achieved, but intermixing between films occurs and critical dimension control deteriorates
Solution Approach 1:
The photoresist layer undergoes pre-baking before lithography exposure to remove volatile components and strengthen the resin structure. This preliminary thermal treatment prevents solvent-related intermixing during subsequent processing steps, thereby improving critical dimension control while eliminating the harmful intermixing effect
Solution Approach 2:
The patent modifies the photoresist composition by incorporating specific resin types and adjusting solvent content to optimize film formation. By changing the chemical parameters of the photoresist system, the process achieves better pattern fidelity and reduces intermixing between the photoresist and underlying films during lithography
2Manufacturing precision
If photoresist layer is coated and processed without cross-linking, then processing is simpler, but pattern precision and resolution deteriorate
Solution Approach 1:
The patent utilizes photo-induced cross-linking to transform the photoresist from a soluble state to an insoluble cross-linked network. This phase transition occurs during post-exposure baking, where exposed regions form a three-dimensional cross-linked structure that maintains sharp pattern boundaries and prevents solvent attack, thereby enhancing pattern precision without requiring complex additional processing steps
Solution Approach 2:
The patent replaces mechanical pattern definition with chemical cross-linking mechanisms. Instead of relying solely on physical mask alignment and mechanical development processes, the invention uses photochemical reactions to create permanently fixed pattern structures that are resistant to subsequent processing, thereby improving pattern precision while keeping the overall process relatively simple
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 approach effectively reduces intermixing between films, maintains pattern precision, and enhances productivity by forming insoluble cross-linked surfaces, thereby improving the resolution and accuracy of semiconductor device patterns.
Implementation Method 1
performing a lithography process to pattern and cross-link a surface of the photoresist layer
Implementation Method 2
The heating may include removing the leaving group. The exposing may include de-blocking a protecting group of the photoresist layer. The heating may be performed within a temperature range from 140° C. to 190° C.
Implementation Method 3
spin-on coating an oxide layer on the photoresist pattern
Implementation Method 4
The processing the oxide layer may include partially etching the oxide layer to form a plurality of oxide spacers
Data Source
AI summary
An example embodiment relates to a patterning process including forming a photoresist pattern on a structure. The photoresist pattern includes a cross-linked surface that is insoluble in an organic solvent. The process also includes spin-on coating a dielectric layer on the photoresist pattern, partially removing the dielectric layer to form a plurality of dielectric spacers surrounding the photoresist pattern, and removing the photoresist pattern.