Amorphous Carbon Photomask Patterning for Line Wiggling Control
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Solution Overview
Problem
High aspect ratio stacking in photo patterning techniques leads to line wiggling and pattern defects, causing metal pattern lines to break and resulting in pattern failure during the formation of integrated circuits.
Innovation Solution
A self-aligned patterning process using a mandrel layer with a conformal spacer layer and amorphous carbon bottom layer deposited by CVD, allowing for greater flexibility and stability in material deposition, and a tri-layer mask structure for improved pattern customization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If high aspect ratio stacking is used in photo patterning, then layer integration density is improved, but line wiggling and pattern defects occur causing pattern failure
Solution Approach 1:
The patent segments the patterning process into multiple stages using a tri-layer mask structure (first mask layer, second mask layer, and etch mask layer) with intermediate spacer layers. This segmentation allows each layer to be optimized independently for its specific function, enabling high aspect ratio structures to be formed without line wiggling while maintaining pattern transfer accuracy.
Solution Approach 2:
The patent applies preliminary actions by forming conformal spacer layers and mandrel structures before the final pattern transfer. The mandrel layer is formed with controlled thickness and material properties beforehand, and spacer layers are deposited conformally to prepare the structure for subsequent etching, preventing line wiggling during the actual pattern transfer process.
2Stability of the object's composition
If conformal spacer layer and amorphous carbon bottom layer are deposited by CVD, then film quality and stability are improved, but process complexity increases
Solution Approach 1:
The amorphous carbon bottom layer serves multiple functions: it provides a stable foundation for subsequent film deposition, acts as an etch stop layer, and prevents line wiggling during pattern transfer. The CVD process is used universally for depositing multiple layers (amorphous carbon, conformal spacers, mask layers) with consistent high quality, reducing the need for different specialized processes.
Solution Approach 2:
The patent controls film quality by precisely adjusting CVD deposition parameters including temperature, pressure, and gas flow rates. The amorphous carbon layer is deposited at specific temperatures to achieve desired density and stress characteristics, while conformal spacer layers are deposited with controlled thickness uniformity, maintaining film stability without excessive process complexity.
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
The process enhances pattern transfer accuracy, reduces line wiggling, and improves the quality of deposited films, ensuring consistent and high-quality film formation for integrated circuits.
Implementation Method 1
a conformal spacer layer and amorphous carbon bottom layer deposited by CVD
Data Source
AI summary
Embodiments utilize a photoetching process in forming a patterned target layer. After forming a patterned mandrel layer and spacer layer over the patterned mandrel layer, a bottom layer of a photomask is deposited using a chemical vapor deposition process to form an amorphous carbon film. An upper layer of the photomask is used to pattern the bottom layer to form openings for a reverse material. The reverse material is deposited in the openings of the bottom layer, the bottom layer providing both a mask and template function for the reverse material.