Nonvolatile Memory Contact Hole Fabrication via Sacrificial Layers
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Solution Overview
Problem
Conventional nonvolatile memory devices using phase-change materials face challenges in achieving low power consumption and reliable data access operations due to limitations in contact hole formation and electrode alignment, leading to inefficiencies in data storage and retrieval.
Innovation Solution
A method of fabricating nonvolatile memory devices involves forming sacrificial layer patterns to create rectangular contact holes and self-aligned bottom electrodes, which improves edge geometry control and reduces power consumption by minimizing the contact area between the electrode and variable resistor pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional contact hole formation methods are used, then manufacturing process is simpler, but contact hole alignment and shape control are poor
Solution Approach 1:
The fabrication process is divided into multiple sequential steps using different sacrificial layer patterns (first sacrificial layer pattern for initial contact hole formation, second sacrificial layer pattern for refinement). This segmentation allows each step to focus on specific aspects of contact hole formation, improving overall precision while managing complexity through systematic breakdown of the process.
Solution Approach 2:
Sacrificial layer patterns are formed in advance before the actual contact hole etching process. These pre-formed patterns serve as precise templates that define the final contact hole geometry and position, ensuring accurate alignment and shape control before the critical etching step occurs.
2Reliability
If larger contact area between electrode and variable resistor is used, then data access reliability is improved, but power consumption increases
Solution Approach 1:
The contact hole geometry is optimized to achieve the appropriate contact area between electrode and variable resistor at the specific location where electrical connection is needed. The rectangular shape with controlled dimensions ensures sufficient contact area for reliable data access while minimizing the overall contact footprint to reduce power consumption.
Data Source
AI summary
A method of fabricating a nonvolatile memory device includes; forming a first sacrificial layer pattern including a first open area that extends in a first direction on a lower dielectric layer, forming a pre-lower dielectric layer pattern including a recess that extends in the first direction using the first sacrificial layer pattern, forming a second sacrificial layer pattern including a second open area that extends in a second direction on the pre-lower dielectric layer pattern and the first sacrificial layer pattern, wherein the second open area intersects the first open area, forming a lower dielectric layer pattern including contact holes spaced apart in the recess using the first sacrificial layer pattern and second sacrificial layer pattern, wherein the contact holes extend to a bottom of the lower dielectric layer pattern, and forming a bottom electrode in the contact hole.