Block Copolymer Self-Assembly for Sub-Resolution Patterning
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Solution Overview
Problem
Current semiconductor fabrication techniques face limitations in achieving fine patterns due to the constraints of exposure process resolution, particularly with the use of KrF and ArF light sources, which require expensive EUV equipment or immersion lithography with refractive index limitations, leading to issues like bubble formation in water-based processes.
Innovation Solution
A method involving a self-assembly induction layer with distinct regions, a block copolymer layer, and specific pattern formation and etching processes to create fine patterns, where the block copolymer layer is phase-separated to form patterns with different materials and shapes, allowing for etching as a mask to achieve finer features than traditional photolithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If immersion lithography process is used to increase numerical aperture and improve resolution, then manufacturing precision is improved, but bubbles are generated at the boundary between water and photoresist layer
Solution Approach 1:
A self-assembly induction layer is introduced as an intermediary between the photoresist layer and the water medium. This induction layer prevents direct contact between water and photoresist, thereby eliminating bubble generation while maintaining the high numerical aperture benefits of immersion lithography. The induction layer acts as a mediator that allows the water-based immersion process to proceed without the harmful bubble formation effect.
2Manufacturing precision
If EUV exposure equipment is used to achieve shorter wavelength and improve resolution, then manufacturing precision is improved, but equipment cost increases significantly
Solution Approach 1:
The patent changes the process parameters by using a self-assembly induction layer that enables conventional exposure equipment to achieve fine patterns through self-assembly mechanisms. Instead of changing to expensive EUV equipment, the invention modifies the photoresist system parameters (adding the induction layer) to enable sub-resolution patterning with existing ArF or KrF excimer laser equipment, thereby avoiding the high equipment cost while achieving improved resolution.
3Ease of manufacture
If conventional photolithography is used to maintain equipment cost, then ease of manufacture is improved, but line width resolution is limited
Solution Approach 1:
The photoresist system is segmented into two functional layers: a conventional photoresist layer and a self-assembly induction layer. The induction layer is designed with specific molecular structures that enable self-assembly into periodic patterns. This segmentation allows the conventional photoresist to be exposed with standard equipment while the induction layer provides the fine pattern definition through self-assembly, achieving sub-resolution line widths without requiring expensive equipment upgrades.
Solution Approach 2:
The self-assembly induction layer is prepared in advance before the actual exposure process. This layer is designed to undergo spontaneous self-assembly into periodic structures when exposed to the excimer laser radiation. By performing this preliminary action of creating the self-assembly capable layer, the system enables fine pattern formation through the inherent self-organizing properties of the material, rather than relying solely on the resolution limits of the exposure equipment.
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 patterns with line widths smaller than those achievable by conventional photolithography, overcoming resolution limits and equipment costs associated with EUV exposure, while maintaining etching resistance and pattern precision.
Implementation Method 1
forming a first pattern, a second pattern, and a third pattern by phase separating the block copolymer
Implementation Method 2
forming a self-assembly induction layer having a first region and a second region on a semiconductor substrate
Data Source
AI summary
Methods of forming a pattern and methods of fabricating a semiconductor device having a pattern are provided, the methods include forming a self-assembly induction layer including a first region and a second region on a semiconductor substrate. A block copolymer layer is coated on the self-assembly induction layer. A first pattern, a second pattern and a third pattern are formed by phase separating the block copolymer. At least one of the first, second and third patterns may be removed to form a preliminary pattern. An etching process may be performed using the preliminary pattern as an etching mask. The first pattern contains the same material as that of the second pattern, and the third pattern contains a material different from that of the first pattern.