Zero Interface Polysilicon Gate Flash Memory
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Solution Overview
Problem
The challenge in flash memory device manufacturing is the formation of impurities, such as silicon oxide, at the interface of poly layers due to exposure to oxygen-containing atmospheres, which affects the quality and reliability of the devices by altering electrical properties.
Innovation Solution
A method and system for processing a zero angstrom oxide interface dual poly gate structure, where an oxide layer on a first poly layer is removed using hydrogen or nitrogen in the same processing chamber before forming a second poly layer, preventing the formation of impurities at the interface between the two poly layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is transferred from the oxide removal tool to another tool, then the oxide layer can be removed from the first poly layer, but the substrate is exposed to oxygen-containing atmosphere causing silicon oxide impurities to form at the interface
Solution Approach 1:
The patent combines the oxide removal process and the second poly layer formation process into a single processing chamber. After removing the oxide layer from the first poly layer using hydrogen or nitrogen, the chamber atmosphere is switched without transferring the substrate, and the second poly layer is immediately formed. This merging eliminates substrate exposure to oxygen-containing atmosphere and prevents silicon oxide impurity formation at the interface.
2Productivity
If multiple processing steps are performed in separate tools, then each step can be optimized independently, but productivity decreases due to repeated transfers and exposure to oxygen-containing atmosphere
Solution Approach 1:
The patent merges multiple processing steps (oxide removal and poly layer formation) into a single processing chamber to eliminate repeated substrate transfers. This reduces exposure time to oxygen-containing atmosphere and prevents impurity formation, thereby improving both productivity and device reliability simultaneously.
Solution Approach 2:
The patent maintains a continuous processing sequence within the same chamber: oxide removal is followed immediately by second poly layer formation without interruption or substrate removal. This continuous action prevents exposure to oxygen-containing atmosphere and ensures the interface remains free of silicon oxide impurities throughout the process.
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 a substantially oxide-free interface, improving the quality and reliability of flash memory devices by preventing impurity formation, thus enhancing their electrical properties and manufacturing productivity.
Implementation Method 1
removing an oxide and/or oxide layer on the surface of a first poly layer by contacting the first poly layer with hydrogen and/or nitrogen to remove oxide
Data Source
AI summary
A system and method are disclosed for processing a zero angstrom oxide interface dual poly gate structure for a flash memory device. An exemplary method can include removing an oxide on a surface of a first poly layer and forming a second poly layer on the first poly layer in a same processing chamber. A transfer of the structure is not needed from an oxide removal tool to, for example, a poly layer formation tool, an implant tool, and the like. As a result, impurities containing a silicon oxide caused by exposure of the first poly layer to an oxygen-containing atmosphere do not form at the interface of the first and second poly layers.