Oxidizing Method for Semiconductor Wafers Using Segmented Gas Supply
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Solution Overview
Problem
Conventional oxidizing methods for semiconductor wafers fail to achieve uniform film thickness and sufficient selective oxidation, especially when different materials like silicon and silicon nitride layers are exposed, leading to inadequate film quality in advanced semiconductor integration circuits.
Innovation Solution
The method involves supplying oxidative gas and reducing gas into a processing container with strategically placed sub-supply units along its length, creating an atmosphere with active oxygen and hydroxyl species, and resupplying oxidative gas partway to maintain uniform film thickness and enable selective oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a wet oxidizing method is used under normal pressure to achieve high oxidation rate, then productivity is improved, but manufacturing precision deteriorates due to poor uniformity within film thickness
Solution Approach 1:
The processing container is divided into multiple zones along the longitudinal direction, with separate oxidative gas supply units positioned at different locations (upstream, middle, downstream). This segmentation allows independent control of oxidation conditions in each zone, enabling high oxidation rates while maintaining uniform film thickness across the wafer surface.
Solution Approach 2:
Different regions of the processing container are provided with tailored gas supply conditions. The upstream region receives oxidative gas to initiate oxidation, the middle region provides continued oxidation, and the downstream region ensures complete oxidation. This local quality approach ensures each area contributes optimally to achieving both high oxidation rate and uniform film thickness.
2Device complexity
If conventional single-point oxidative gas supply is used, then device complexity is reduced, but manufacturing precision deteriorates due to non-uniform film thickness
Solution Approach 1:
Instead of a single gas supply point, the system uses multiple oxidative gas supply units positioned at different longitudinal locations within the processing container. This segmentation of the gas supply system enables precise control of oxidation conditions across different zones, achieving uniform film thickness without excessive complexity.
3Ease of operation
If hydrogen-burning oxidizing method is used under relatively high pressure, then ease of operation is improved, but manufacturing precision deteriorates due to density difference of moisture vapor causing non-uniform film thickness
Solution Approach 1:
The system changes the oxidation mechanism from moisture vapor-based (hydrogen-burning) to direct oxidative gas-based oxidation. By introducing oxidative gas directly at multiple positions, the method eliminates reliance on moisture vapor density gradients, achieving uniform film thickness while maintaining ease of operation through simplified gas control.
4Adaptability or versatility
If conventional oxidizing method is used for selective oxidation, then selectivity is improved, but manufacturing precision deteriorates due to inadequate control of oxidation extent
Solution Approach 1:
The processing container is segmented into multiple zones with independent oxidative gas supply, allowing different oxidation conditions in each zone. This enables precise control of oxidation extent for selective oxidation processes, achieving both material selectivity and accurate film thickness control.
Solution Approach 2:
The system provides dynamic control of oxidation conditions by independently adjusting gas flow rates at different positions. This dynamic capability allows real-time optimization of oxidation parameters to achieve desired selectivity and film thickness precision simultaneously.
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 high uniformity in film thickness and allows for selective oxidation of different materials, preventing excessive oxidation of silicon nitride layers and maintaining the designed ONO-film structure, thereby improving the quality of oxide films formed on semiconductor wafers.
Implementation Method 1
supplying the oxidative gas and the reducing gas into the processing container in order to form an atmosphere having active oxygen species and active hydroxyl species
Implementation Method 2
the active species rise up in the processing container, come in contact with surfaces of the wafers W, and oxidize the surfaces
Data Source
AI summary
An oxidizing method for an object to be processed according to the present invention includes: an arranging step of arranging a plurality of objects to be processed in a processing container whose inside can be vacuumed, the processing container having a predetermined length, a main supplying unit of an oxidative gas and a supplying unit of a reducing gas being provided at one end of the processing container, a sub supplying unit of the oxidative gas being provided on a way in a longitudinal direction of the processing container; an atmosphere forming step of supplying the oxidative gas and the reducing gas into the processing container in order to form an atmosphere having active oxygen species and active hydroxyl species in the processing container; and an oxidizing step of oxidizing surfaces of the plurality of objects to be processed in the atmosphere. In the atmosphere forming step, the oxidative gas is adapted to be supplied from the main supplying unit of the oxidative gas and the sub supplying unit of the oxidative gas.