Block Copolymer Pattern Formation via Selective Plasma Etching
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Solution Overview
Problem
Existing methods for forming periodic patterns using block copolymers struggle with selective etching of polymer components, leading to inadequate masking during the etching process due to similar etching rates of PMMA and ArF photoresist films, resulting in incomplete pattern formation and reduced effectiveness in semiconductor manufacturing.
Innovation Solution
A method involving self-assembly of block copolymers, where a first polymer and a second polymer are etched using plasma-generated gases, followed by deposition of protective films to selectively etch the second polymer, allowing for precise control of the etching process and improved pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If PMMA and ArF photoresist film are etched using conventional plasma etching, then the etching process can be performed, but the selective ratio between PMMA and ArF photoresist film becomes insufficient because they have similar etching rates, resulting in inadequate masking and incomplete pattern formation
Solution Approach 1:
The patent applies preliminary action by depositing a protective film on the ArF photoresist film before the etching process begins. This protective film is deposited in advance to prevent the photoresist from being etched during subsequent PMMA etching, thereby ensuring adequate masking from the start of the process
Solution Approach 2:
The protective film acts as an intermediary layer between the PMMA and the ArF photoresist film. It mediates the etching process by providing a barrier that prevents the plasma from directly attacking the photoresist, allowing selective removal of PMMA while preserving the underlying photoresist structure
2Productivity
If the etching rate of PMMA is increased to improve pattern formation speed, then productivity increases, but the selective ratio between PMMA and ArF photoresist film decreases further, worsening the masking problem
Solution Approach 1:
By depositing the protective film in advance, the system enables higher etching rates to be used without compromising pattern quality. The pre-deposited protective film ensures that even at increased etching speeds, the photoresist remains protected, allowing productivity improvement without sacrificing manufacturing precision
Solution Approach 2:
The patent changes the process parameters by introducing a protective film layer, which fundamentally alters the etching dynamics. This parameter change allows the system to operate at higher etching rates while maintaining or improving pattern formation quality, as the protective film prevents the harmful effects that would normally limit etching speed
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 enables the formation of precise periodic patterns while depositing protective films, enhancing the selective ratio of PMMA to the guide layer and maintaining the integrity of the guide layer, thus improving the etching process and pattern quality in semiconductor devices.
Implementation Method 1
a block copolymer layer containing at least two polymer block components A and B that do not mix with each other is applied to an underlayer film. After that, the polymer block components A and B spontaneously separate in phase from each other by being annealed.
Implementation Method 2
a first etching step of etching the second polymer by plasma generated from a first gas
Data Source
AI summary
A method for causing a first polymer and a second polymer of a block copolymer to be self-assembled on an underlayer film and forming a periodic pattern in a guide layer is provided. The method includes a first etching process of etching the second polymer by plasma generated from a first gas, a first film deposition process of depositing a first protective film on surfaces of the first polymer and the guide layer except for an etched portion of the second polymer by plasma generated from a second gas after the first etching process, and a second etching process of further etching the second polymer by the plasma generated from the first gas after the first film deposition process.