Low-Temperature Liner Deposition for Phase Change Memory
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Solution Overview
Problem
Conventional semiconductor fabrication methods expose temperature-sensitive materials to detrimental thermal conditions exceeding 300° C, which can alter or render them inoperable, posing challenges in developing suitable fabrication sequences for structures like phase change memory arrays.
Innovation Solution
The method involves forming liners along the sidewalls of features using temperature-resistant materials like silicon nitride, which are deposited and cured below 300° C, followed by filling the gaps with flowable materials that are also cured at non-detrimental temperatures, preventing chemical interaction and delamination, and ensuring the temperature-sensitive materials are not exposed to high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional thermal processing is used for depositions and cures, then manufacturing processes can be completed, but temperature-sensitive materials are exposed to temperatures exceeding 300° C causing chemical and physical alteration
Solution Approach 1:
The patent changes the temperature parameter from conventional high-temperature processing (>300° C) to low-temperature processing (<300° C). This is achieved by using plasma-enhanced chemical vapor deposition (PECVD) and other low-temperature fabrication techniques that enable complete manufacturing processes while maintaining temperature-sensitive materials within safe thermal limits, thus resolving the contradiction between manufacturing completion and thermal damage prevention
Solution Approach 2:
The patent introduces plasma as an intermediary medium that enables chemical reactions and material deposition at lower temperatures. The plasma provides reactive species that facilitate deposition and curing processes without requiring high thermal energy, thereby allowing manufacturing completion while protecting temperature-sensitive materials from thermal degradation
2Reliability
If temperature-resistant materials like silicon nitride are used for liners, then protection against chemical interaction is improved, but deposition and curing temperatures may still threaten temperature-sensitive materials
Solution Approach 1:
The patent applies plasma-enhanced chemical vapor deposition (PECVD) to deposit silicon nitride liners at temperatures below 300° C. The plasma activation enables the formation of high-quality, chemically resistant liner materials at low temperatures, thus achieving both protection against chemical interaction and avoidance of thermal damage to temperature-sensitive materials simultaneously
Solution Approach 2:
The patent replaces conventional thermal processing mechanisms with plasma-based mechanisms for liner deposition. Instead of relying on high thermal energy to drive chemical reactions, the system uses plasma-generated reactive species and ion bombardment to enable low-temperature deposition of protective liners, thereby maintaining both reliability and temperature control
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 allows for the fabrication of structures without damaging temperature-sensitive materials, preventing thermal degradation and ensuring reliable operation by maintaining the materials within safe thermal limits during processing.
Implementation Method 1
flowable material to fill gaps between the spaced-apart features
Implementation Method 2
utilizing flowable material which is cured under conditions which do not expose the temperature-sensitive material to a temperature in excess of 300° C
Implementation Method 3
The liners may, for example, protect materials of the features from chemically reacting with the flowable material
Data Source
AI summary
Some embodiments include methods of forming structures. Spaced-apart features are formed which contain temperature-sensitive material. Liners are formed along sidewalls of the features under conditions which do not expose the temperature-sensitive material to a temperature exceeding 300° C. The liners extend along the temperature-sensitive material and narrow gaps between the spaced-apart features. The narrowed gaps are filled with flowable material which is cured under conditions that do not expose the temperature-sensitive material to a temperature exceeding 300° C. In some embodiments, the features contain memory cell regions over select device regions. The memory cell regions include first chalcogenide and the select device regions include second chalcogenide. The liners extend along and directly against the first and second chalcogenides.