Diblock Copolymer Self-Assembly for Contact Hole Alignment
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Solution Overview
Problem
Conventional semiconductor device fabrication methods face challenges in precisely aligning contact holes with doped areas due to misalignment issues, especially as critical dimensions shrink, leading to reduced yield and potential damage to gate lines.
Innovation Solution
A method involving the use of diblock copolymers, where a self-assembly process forms a circular pattern over a doped area within a recessed interlayer dielectric layer, allowing for precise alignment of contact holes by etching through the diblock copolymer and hard mask layers, ensuring accurate placement and small size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography is used to form contact holes, then the process is simple and compatible with standard fabrication, but misalignment between contact holes and doped areas occurs leading to poor manufacturing precision
Solution Approach 1:
The fabrication process is divided into distinct stages: forming the interlayer dielectric layer with recesses, depositing the diblock copolymer, performing self-assembly to create circular patterns, and selective etching. This segmentation allows each step to be optimized independently, achieving high precision without overwhelming complexity
Solution Approach 2:
The diblock copolymer performs self-assembly to automatically form circular patterns centered on the recesses of the interlayer dielectric layer. This self-organizing behavior eliminates the need for complex alignment procedures, achieving high manufacturing precision through the material's inherent self-structuring capability
2Length of moving object
If photolithography is used with photoresist, then the process is straightforward, but the critical dimension control reaches its limitation as dimensions shrink
Solution Approach 1:
The method changes the fundamental parameter of pattern formation from optical lithography to self-assembly of diblock copolymers. This transition enables critical dimensions below the diffraction limit of light while maintaining precise alignment, as the self-assembly process is governed by molecular-scale interactions rather than optical resolution
Solution Approach 2:
The invention moves from two-dimensional photolithographic patterning to three-dimensional self-assembly of diblock copolymers within the recesses of the interlayer dielectric layer. The vertical confinement in the recesses guides the self-assembly process, enabling precise control of contact hole size and position that cannot be achieved with conventional planar lithography
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 ensures precise alignment and small-sized contact holes, improving semiconductor device yield while being compatible with standard fabrication processes, thus reducing costs.
Implementation Method 1
performing a self-assembly process on the diblock copolymer, so as to form a circular pattern of the first component above the doped area, the circular pattern of the first component being surrounded by the second component
Data Source
AI summary
The present disclosure relates to a method of fabricating semiconductor devices. In the method provided by the present invention, by filling with diblock copolymer a recess of an interlayer dielectric layer naturally formed between two gate lines and then performing a self-assembly process of the diblock copolymer, a small-sized contact hole precisely aligned with an doped area can be formed, and thus misalignment between the contact hole and the doped area can be eliminated or alleviated.