Phase-Change Memory Self-Aligned Contact via Etch Rate Differential
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Solution Overview
Problem
The complexity and inefficiency of the semiconductor photolithography process in fabricating semiconductor phase-change memory devices, due to the need for multiple conductive patterns with different dimensions, complicate the structure and fabrication method.
Innovation Solution
A semiconductor phase-change memory device design where a data storage structure with a concave portion is aligned with a data line, and a data contact structure is configured to contact both, with different etch rates for insulating and conductive materials, allowing for self-alignment without the need for repeated photolithography processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple conductive patterns with different dimensions are formed using one-time semiconductor photolithography process, then the data contact structure can contact the data storage structure, but the photolithography process must be repeated multiple times which complicates the fabrication method
Solution Approach 1:
The data contact structure is divided into multiple conductive patterns with different dimensions, where each pattern is formed in a separate interlayer insulating layer. This segmentation allows each layer to be formed independently through sequential photolithography processes, enabling complex contact structures to be built up step-by-step without requiring complete restructuring.
Solution Approach 2:
The patent transitions from forming all conductive patterns in a single planar layer to distributing them across multiple vertical layers (interlayer insulating layers). This dimensional transition from 2D to 3D arrangement allows multiple patterns with different dimensions to coexist without interfering with each other's photolithography formation, reducing overall fabrication complexity.
2Reliability
If the data contact structure has multiple conductive patterns with different dimensions stacked sequentially, then contact with data storage structure is achieved, but the number of photolithography processes increases
Solution Approach 1:
The lower portion of the data contact structure is formed first by filling the concave portion of the data storage structure, establishing a preliminary contact foundation. Subsequent upper portions are then added in sequence, each building upon the previous layer. This preliminary action approach ensures reliable contact transmission is established early, while the modular sequential addition minimizes the total number of photolithography processes required.
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 design minimizes the number of semiconductor photolithography processes required, simplifying the fabrication method and improving the integration of data storage and contact structures within the device.
Implementation Method 1
the lower portion of the data contact structure comprises insulating materials that are sequentially stacked and have different etch rates
Data Source
AI summary
A semiconductor phase-change memory device comprises a data line disposed on a semiconductor substrate and a data storage structure disposed under the data line and having a concave portion extending in a direction along the data line. A data contact structure is configured to contact the data storage structure, and having a lower portion filling the concave portion of the data storage structure and an upper portion surrounding at least a lower portion of the data line. Each of sidewalls of the data storage structure is disposed at substantially the same plane as a corresponding one of sidewalls of the upper portion of the data contact structure.