Selective Oxide Passivation for Semiconductor Cleaning Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor processing methods struggle to effectively retain desired oxide layers during cleaning operations, leading to over-etching and potential epitaxial merging issues.
Innovation Solution
The method involves etching a silicon-containing material from a substrate to form recesses, forming a low quality oxide within these recesses, and then selectively passivating the oxide using an organosilane agent. This passivation process protects the oxide layer while allowing the target material to be etched at an equal or faster rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cleaning operations are used to remove silicon-containing material, then the cleaning effectiveness is improved, but the oxide layers are also removed leading to over-etching and epitaxial merging issues
Solution Approach 1:
A passivating agent is introduced as an intermediary substance that selectively bonds to oxide layers, creating a protective interface between the cleaning agent and the oxide. This mediator allows the cleaning agent to remove silicon-containing material while the passivating agent prevents the cleaning agent from attacking the oxide layers, thus resolving the contradiction between cleaning effectiveness and oxide layer retention.
Solution Approach 2:
The passivating agent provides different protective properties to different areas of the substrate. By selectively passivating oxide layers while leaving silicon-containing material exposed, the system creates local quality differences that enable differential etching rates. This allows the cleaning process to affect only the intended material (silicon-containing) while preserving the oxide layers in specific locations.
2Reliability
If the etch rate of oxide layers is reduced to prevent over-etching, then epitaxial merging is minimized, but the cleaning efficiency decreases
Solution Approach 1:
The passivating agent serves as a mediator that decouples the relationship between cleaning agent and oxide layers. Instead of directly reducing the etch rate of oxide layers (which would reduce cleaning efficiency), the passivating agent intervenes to protect the oxide layers, allowing the cleaning agent to maintain its high etch rate on silicon-containing material while the oxide layers are protected through the intermediary protective layer.
3Device complexity
If conventional cleaning agents are used without passivation, then the process simplicity is maintained, but selective etching control is lost
Solution Approach 1:
The passivation step is performed as a preliminary action before the cleaning/etching process. By pre-applying the passivating agent to protect oxide layers before introducing the cleaning agent, the system establishes selective etching control in advance. This preliminary protective measure allows the subsequent cleaning process to proceed with high selectivity without requiring complex real-time control mechanisms.
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 reduces the etch rate of low quality oxides while maintaining the etch rate of the target material, thereby minimizing the risk of epitaxial merging and other defects associated with over-etching.
Implementation Method 1
the passivating agent undergoes a silylation process with one or more hydroxyl groups
Implementation Method 2
contacting the substrate with an etching agent and/or a cleaning agent, wherein the contacting with the cleaning agent removes the silicon-containing material at an equal or faster rate than the low quality oxide
Data Source
AI summary
Exemplary methods and systems of semiconductor processing may include etching a portion of a silicon-containing material from a substrate disposed within a processing region of a semiconductor processing chamber. Methods may include forming a low quality oxide within one or more of the recesses, where the low quality oxide and a silicon-containing material each contain an exposed surface. Methods include contacting the low quality oxide and the high quality semiconductor material with a passivating agent selective to a surface defect of the low quality oxide. Methods include contacting the substrate with an etching agent and/or a cleaning agent, where the contacting with the cleaning agent removes the high quality semiconductor material at an equal or faster rate than the low quality oxide.