Contact Hole Formation via Block Copolymer Self-Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for forming contact holes with minute pitches below 40 nm are limited by photolithography resolution and are complex, and direct self-assembly methods face challenges in achieving desired arrangements due to thermodynamic stability issues with hexagonal material arrangements.
Innovation Solution
A method involving the formation of guide patterns and block copolymer structures with specific material layers and pitches, followed by etching processes, to create contact holes with desired arrangements and pitches of 20 to 50 nm, using polymethyl methacrylate (PMMA) and polystyrene (PS) materials, allowing for the formation of contact holes with non-hexagonal shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography is used for forming patterns, then conventional manufacturing processes can be applied, but it is difficult to form patterns with minute pitch below 40 nm due to resolution limits
Solution Approach 1:
The patent applies segmentation by dividing the pattern formation process into multiple stages using guide patterns and block copolymer structures. The guide patterns are segmented into first and second guide patterns with respective openings, allowing the formation of contact holes at pitches (20-50 nm) that are below the resolution limit of conventional photolithography.
Solution Approach 2:
The patent uses guide patterns as intermediary structures to enable the formation of contact holes at ultra-fine pitches. The guide patterns with first and second openings serve as mediators that guide the self-assembly of block copolymers, allowing precise positioning of contact holes at 20-50 nm pitches without directly relying on photolithography resolution.
2Manufacturing precision
If direct self assembly (DSA) method is used to form minute pitch patterns, then contact holes with desired pitch can be formed, but the material arranges in hexagonal shape due to thermodynamic stability making it difficult to achieve desired arrangements
Solution Approach 1:
The patent applies asymmetry by designing guide patterns with rectangular openings instead of allowing natural hexagonal self-assembly. The first guide pattern has first openings and the second guide pattern has second openings arranged in specific asymmetric configurations that guide the block copolymer material to form contact holes in desired rectangular arrangements rather than thermodynamically stable hexagonal shapes.
Solution Approach 2:
The patent uses preliminary action by forming guide patterns before the block copolymer self-assembly process. The guide patterns with predetermined opening positions and shapes are created in advance to direct and constrain the subsequent self-assembly of block copolymers, ensuring the material forms the desired rectangular contact hole arrangement rather than natural hexagonal structures.
3Manufacturing precision
If multiple guide patterns and block copolymer structures are formed sequentially, then contact holes with precise arrangement and pitch of 20 to 50 nm can be achieved, but the process complexity increases
Solution Approach 1:
The patent applies self-service by utilizing the self-assembly property of block copolymers to automatically form ordered structures within the guide pattern openings. The block copolymers spontaneously organize themselves into the desired configurations without requiring additional complex processing steps, reducing overall process complexity while maintaining precision.
Solution Approach 2:
The patent uses nested doll by forming a second guide pattern within and aligned to the first guide pattern structure. The second guide pattern openings are positioned to correspond with the first guide pattern openings, creating a nested configuration that enables precise contact hole formation through sequential but integrated processing steps.
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
Enables the formation of contact holes with precise arrangement and pitch control, overcoming the limitations of existing technologies by achieving contact holes with pitches as low as 20 to 50 nm and allowing for desired geometric configurations.
Implementation Method 1
a first block copolymer (BCP) structure is formed in each of the first openings. The first BCP structure includes a plurality of first material layers arranged in the first direction at a first pitch in each of the first openings
Implementation Method 2
a method of forming a minute pitch pattern, particularly, contact holes using a direct self assembly (DSA) has been developed
Implementation Method 3
The first BCP layer may be annealed
Implementation Method 4
the first material layers may be removed by performing a dry etching process or a wet etching process
Implementation Method 5
the first material layers may be removed by performing a dry etching process or a wet etching process
Data Source
AI summary
Methods of forming contact holes include forming a first guide pattern over an etching target layer. The first guide pattern has first openings each extending in a first direction and each first opening arranged in a direction perpendicular to the first direction. A first BCP structure is formed in each first opening. The first BCP structure includes first material layers in the first direction at a first pitch in each of the first openings, and second material layers filling a remaining portion of each first opening. First holes are formed by removing the first material layers. A second guide pattern is formed over the first guide pattern and the second material layers, and the above processes are performed on the second guide pattern to form second holes. Portions of the etching target layer overlapped by the first holes or the second holes are removed to form a desired pattern.