Resist-Modifying Composition for Double Patterning Alignment
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Solution Overview
Problem
Current double patterning processes face challenges in forming effective alignment pattern features due to insufficient retention of large area pattern features during the freezing process, leading to misregistration and reduced throughput, especially when using resist-modifying compositions that fail to adequately inactivate the first resist pattern for the second resist process.
Innovation Solution
A process involving a first positive resist composition with a polymer having recurring units that increase alkali solubility and lactone structure, combined with a resist-modifying composition containing a basic nitrogen-containing compound, allows for the retention of large area pattern features and effective alignment marks, enabling a double patterning process with single dry etching and improved alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resist-modifying composition is applied to inactivate the first resist pattern, then the first resist pattern can be modified for the second resist process, but the large area pattern feature is lost due to insufficient retention
Solution Approach 1:
The patent changes the chemical parameters of the resist-modifying composition by specifying a basic nitrogen-containing compound with a conjugate acid pKa of at least 4. This parameter change ensures adequate reaction with the acid generated during the second exposure, thereby retaining the large area pattern feature while enabling the second resist process to proceed correctly.
Solution Approach 2:
The basic nitrogen-containing compound acts as an intermediary substance that mediates between the first resist pattern and the second resist process. It neutralizes the acid generated during the second exposure in the large area pattern feature, preventing its dissolution while allowing the second resist pattern to form correctly.
2Manufacturing precision
If double patterning process is used to form fine size pattern, then the pattern rule can be made finer, but the throughput is reduced due to multiple processing steps
Solution Approach 1:
The patent performs preliminary inactivation of the first resist pattern using a resist-modifying composition before the second resist process. This preliminary action ensures that the first pattern is properly prepared to serve as a mask during the second exposure, enabling fine pattern formation while maintaining process efficiency.
Solution Approach 2:
The patent uses a disposable resist-modifying composition that is applied and then removed or integrated into the structure. This approach allows for a streamlined process where the modifying composition serves its purpose and can be discarded or incorporated without requiring complex recovery or reuse mechanisms, thereby maintaining throughput.
3Productivity
If the first resist pattern is not adequately inactivated, then the second resist process can proceed, but misregistration occurs due to loss of alignment marks
Solution Approach 1:
The patent applies local quality by ensuring that the basic nitrogen-containing compound is specifically retained in the large area pattern feature where alignment marks are formed. This localized retention ensures that alignment marks remain intact for accurate registration during the second resist process, while other areas of the resist pattern can be adequately inactivated.
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 proposed process effectively retains large area pattern features and forms fine size patterns with enhanced alignment accuracy, overcoming the limitations of existing double patterning techniques by ensuring the first resist pattern is adequately modified for the second resist process, thus improving throughput and pattern fidelity.
Implementation Method 1
applying a resist-modifying composition comprising a basic nitrogen-containing compound having a conjugate acid pKa of at least 4 to the first resist pattern and heating to modify the first resist pattern
Implementation Method 2
a polymer comprising recurring units adapted to increase alkali solubility under the action of acid and recurring units having lactone structure
Implementation Method 3
applying a resist-modifying composition comprising a basic nitrogen-containing compound having a conjugate acid pKa of at least 4 to the first resist pattern and heating to modify the first resist pattern
Data Source
AI summary
A pattern is formed by (1) coating a first positive resist composition onto a substrate, baking, patternwise exposing, PEB, and developing to form a first positive resist pattern including a large area feature, (2) applying a resist-modifying composition comprising a basic nitrogen-containing compound and heating to modify the first resist pattern, and (3) coating a second positive resist composition thereon, patternwise exposing, and developing to form a second resist pattern. The large area feature in the first resist pattern has a film retentivity of at least 50% after the second pattern formation.