Negative Tone Photoresist Template Patterning for Block Copolymer Self-Assembly
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Solution Overview
Problem
Conventional methods for forming patterned template materials for chemical pattern-directed self-assembly of block copolymers are inefficient, costly, and pose health, safety, and environmental concerns due to the limited number of suitable plasma and developer chemistries, particularly requiring hazardous materials like dimethyl sulphoxide (DMSO).
Innovation Solution
A method involving the formation of a template material with preferential wetting to a polymer block, followed by a photoresist material exposed to radiation, where non-photoexposed regions are removed with a negative tone developer, and then the patterned photoresist and template material are processed with an oxidizing plasma, allowing for the use of a positive tone developer to finalize the patterned template, thereby reducing complexity and hazardous material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods using positive tone photoresist and negative tone developer (e.g., DMSO) are used to form patterned template material, then the patterned template material can be formed for block copolymer self-assembly, but the process becomes costly, inefficient, and requires hazardous materials with specialized equipment
Solution Approach 1:
The patent inverts the conventional approach by using negative tone photoresist instead of positive tone photoresist. This inversion allows the use of positive tone developers (which are less hazardous and more commonly available) rather than negative tone developers like DMSO. The negative tone photoresist forms patterns where unexposed regions remain, enabling the same patterning function to be achieved with a reversed chemistry approach that eliminates the need for specialized hazardous material handling equipment
Solution Approach 2:
The patent changes the chemical parameters of the photoresist system by selecting a negative tone photoresist with specific compositional characteristics. This parameter change enables compatibility with a broader range of developer chemistries, particularly positive tone developers, while maintaining the required patterning precision for block copolymer self-assembly. The altered photoresist parameters allow for more flexible and safer processing conditions
2Manufacturing precision
If conventional methods with limited plasma and developer chemistries are used, then patterned template material can be formed, but the number of suitable chemistries is restricted and requires hazardous materials
Solution Approach 1:
The patent achieves universality by selecting a negative tone photoresist that can be processed with multiple types of plasma chemistries and positive tone developers. This multi-functional photoresist formulation allows the same patterning process to work with various etch chemistries (fluorocarbon, oxygen, nitrogen-based plasmas) and different positive tone developer solutions, eliminating the restriction to a single or limited chemistry pathway and enabling greater process flexibility and adaptability
3Ease of manufacture
If hazardous materials like DMSO are used for negative tone development, then patterned photoresist material can be removed, but health, safety, and environmental concerns arise requiring specialized equipment
Solution Approach 1:
The patent converts the potential harm of requiring specialized hazardous material handling into a benefit by using negative tone photoresist that can be removed with positive tone developers. These positive tone developers are generally less hazardous, more environmentally friendly, and do not require specialized equipment for safe handling. The inversion of the tone approach transforms a harmful dependency into a beneficial one, improving health and safety outcomes while maintaining manufacturing ease
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 method enhances efficiency, reduces costs, and mitigates health and environmental concerns while achieving feature dimensions comparable to or better than conventional methods, using a broader range of etch chemistries and less toxic materials.
Implementation Method 1
forming a template material exhibiting preferential wetting to a polymer block of a block copolymer over a substrate
Implementation Method 2
A photoresist material may be formed over the template material, and may be selectively exposed to radiation to form a photoexposed photoresist material
Implementation Method 3
The patterned photoresist material and regions of the template material unprotected by (e.g., exposed through) the patterned photoresist material may be exposed to an oxidizing plasma to remove portions of the patterned photoresist material and the template material
Data Source
AI summary
A method of forming a semiconductor device structure comprises forming a template material over a substrate, the template material exhibiting preferential wetting to a polymer block of a block copolymer. A positive tone photoresist material is formed over the template material. The positive tone photoresist material is exposed to radiation to form photoexposed regions and non-photoexposed regions of the positive tone photoresist material. The non-photoexposed regions of the positive tone photoresist material are removed with a negative tone developer to form a pattern of photoresist features. The pattern of photoresist features and unprotected portions of the template material are exposed to an oxidizing plasma to form trimmed photoresist features and a pattern of template features. The trimmed photoresist features are removed with a positive tone developer. Other methods of forming a semiconductor device structure, and a semiconductor device structure are also described.