Block Copolymer Phase Separation for Narrow Pitch Pattern Formation
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Solution Overview
Problem
Current methods for forming fine patterns in semiconductor manufacturing using block copolymers are limited in reducing the pitch between hole patterns, as the pitch is controlled by the arrangement of resist film patterns, and using oxide films as guides leads to gaps and increased treatment steps, making it difficult to achieve the required density for higher-density DRAM capacitors.
Innovation Solution
A substrate treatment method involving the use of a block copolymer with a hydrophilic and hydrophobic polymer ratio of 20% to 40%, where the block copolymer is applied after forming circular resist patterns, phase-separated, and the hydrophilic polymer is selectively removed, allowing the hydrophobic polymer to guide the phase-separation of the second block copolymer, preventing gaps and unnecessary patterns during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If oxide films are used as guides for phase-separation, then pattern formation is enabled, but gaps are formed between guides and polymers, and treatment steps increase
Solution Approach 1:
The patent uses hydrophobic polymers as intermediary guides instead of oxide films. These hydrophobic polymer guides enable phase-separation of hydrophilic polymers without forming gaps, as they directly interact with the block copolymer structure. This intermediary approach eliminates the need for additional treatment steps while maintaining pattern formation precision.
Solution Approach 2:
The patent changes the guiding mechanism from oxide film-based physical guides to hydrophobic polymer-based chemical guides. By changing the interaction parameter from physical contact with oxide surfaces to chemical affinity with hydrophobic polymers, the system achieves gap-free pattern formation and reduces treatment complexity.
2Manufacturing precision
If resist pattern arrangement controls pitch, then pattern formation is achieved, but pitch reduction is limited
Solution Approach 1:
The patent enables the block copolymer system to self-organize into desired patterns through phase-separation guided by hydrophobic polymers. The system automatically forms narrow-pitch patterns without requiring dense resist pattern arrangements, as the phase-separation process itself generates the fine patterns. This self-service mechanism overcomes the resist pattern density limitation.
Solution Approach 2:
The patent segments the pattern formation process into two independent stages: first forming hydrophobic polymer guides, then using them to guide phase-separation of hydrophilic polymers. This segmentation allows the pitch to be determined by the phase-separation process rather than the resist pattern arrangement, enabling greater pitch reduction flexibility.
3Manufacturing precision
If block copolymer phase-separation is used, then fine patterns are formed, but gaps are transferred to the film during etching
Solution Approach 1:
The hydrophobic polymers serve as intermediary masks that prevent gap transfer to the film. They maintain direct contact with the etching process, ensuring that the etching pattern perfectly matches the hydrophobic polymer pattern without gaps. This intermediary role eliminates the harmful gap transfer effect while preserving fine pattern formation capability.
Solution Approach 2:
The patent creates a perfect copy of the hydrophobic polymer pattern onto the film through etching. By using hydrophobic polymers as masks, the etching process exactly replicates their pattern without introducing gaps, achieving faithful pattern copying from the polymer guide to the final film structure.
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 allows for the appropriate formation of predetermined patterns on a substrate without transferring gaps to the film, enabling narrower pitches and improving throughput by eliminating the need for additional treatment steps and using hydrophobic polymers as guides instead of oxide films.
Implementation Method 1
the block copolymer is phase-separated into a hydrophilic polymer and a hydrophobic polymer
Implementation Method 2
the hydrophobic polymer to guide the phase-separation of the second block copolymer, preventing gaps and unnecessary patterns during etching
Data Source
AI summary
A substrate treatment method includes: forming a plurality of circular patterns of a resist film on a substrate; thereafter applying a first block copolymer; then phase-separating the first block copolymer into a hydrophilic polymer and a hydrophobic polymer; thereafter selectively removing the hydrophilic polymer; then selectively removing the resist film from a top of the substrate; thereafter applying a second block copolymer to the substrate; then phase-separating the second block copolymer into a hydrophilic polymer and a hydrophobic polymer; and thereafter selectively removing the hydrophilic polymer from the phase-separated second block copolymer. A ratio of a molecular weight of the hydrophilic polymer in the first block copolymer and the second block copolymer is 20% to 40%.