Multi-Cassette Diffusion Furnace for Uniform Wafer Processing
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Solution Overview
Problem
The vertical quartz tube structure of diffusion furnaces used in semiconductor manufacturing leads to significant differences in reaction conditions between upper and lower wafers, resulting in non-uniform film quality, increased process time, and difficulties in equipment maintenance due to its height and narrow width.
Innovation Solution
A diffusion furnace design featuring a furnace tube structure with a reduced height and increased width, incorporating a carrying structure with multiple cassettes and a rotatable pedestal, along with a gas path system for uniform gas distribution, to minimize reaction condition differences and facilitate easier maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vertical quartz tube structure with large height is used to accommodate 100-125 wafers, then the productivity is improved, but the manufacturing precision deteriorates due to great difference in reaction conditions between upper and lower wafers
Solution Approach 1:
The patent transitions from a vertical arrangement (single column) to a horizontal arrangement (multiple columns), changing the spatial dimension of wafer placement. This allows multiple wafers to be processed side-by-side at similar reaction conditions, eliminating the height-related gradient issues while maintaining high throughput capacity.
Solution Approach 2:
The reaction chamber is divided into multiple independent columns, each capable of holding and processing wafers separately. This segmentation allows each column to operate under more uniform conditions, improving film quality consistency while the multi-column configuration collectively handles large numbers of wafers.
2Productivity
If a vertical furnace tube with large height and small width is used, then the productivity is improved, but the ease of repair deteriorates due to difficulty of equipment maintenance
Solution Approach 1:
By switching from vertical to horizontal orientation, the patent creates wider access spaces around the furnace tube. Maintenance personnel can approach the tube from multiple sides at ground level, making it much easier to perform repairs and inspections without climbing or working in confined spaces.
Solution Approach 2:
Instead of making the furnace tube taller to increase capacity, the patent inverts the approach by making it wider and shorter. This inversion prioritizes maintenance accessibility while achieving the same or greater wafer processing capacity through increased width rather than height.
3Productivity
If a vertical quartz tube structure with large height is used, then the productivity is improved, but the loss of time increases due to multiplication of process time
Solution Approach 1:
The horizontal multi-column configuration allows for more efficient gas flow distribution and heat uniformity, enabling shorter process times to achieve the same film quality. Multiple columns can be processed simultaneously under optimized conditions, reducing the time each batch requires while maintaining high throughput.
Data Source
AI summary
The present application discloses a diffusion furnace, including: a furnace tube structure including a furnace tube body and a furnace bottom, a bottom of the furnace tube body being connected to the furnace bottom to form a reaction chamber; and a carrying structure including a pedestal and a plurality of cassettes disposed on the pedestal, the pedestal being disposed on the furnace bottom. By disposing the plurality of the cassettes, a height of the furnace tube body can be decreased and a width of the furnace tube body can be increased, thus enlarging a space of equipment repair and maintenance, which is favorable for the repair and maintenance of the equipment.