Large-Diameter Silicon Electrode Plate via Segmented Crystal Growth
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Solution Overview
Problem
The production of large-diameter single-crystalline silicon electrode plates for semiconductor devices is challenging due to difficulties in growing wide-diameter single-crystalline silicon, leading to non-uniform etching and device failures caused by particle formation and impurities at crystal grain boundaries when poly-crystalline silicon is used.
Innovation Solution
A silicon member is fabricated by sawing a columnar crystal silicon ingot grown from seed crystals aligned in the same crystal orientation, reducing crystal grain boundaries and allowing for the production of electrode plates with diameters exceeding 450 mm, which maintains etching uniformity and reduces impurity-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If poly-crystalline silicon is used for the electrode plate, then large-diameter electrode plates can be produced, but particle formation and device failures occur due to crystal grain boundaries
Solution Approach 1:
The electrode plate is divided into multiple single-crystal regions, each grown from a separate seed crystal. By segmenting the growth process into multiple controlled single-crystal regions rather than attempting to grow one large single crystal, the method achieves large overall diameter while maintaining single-crystal quality in each segment, eliminating crystal grain boundary issues.
Solution Approach 2:
Multiple single-crystal regions grown from individual seed crystals are combined to form a large-diameter electrode plate. The individual single-crystal segments are merged during the solidification process to create a unified large-diameter structure that maintains the benefits of single-crystal material throughout.
2Manufacturing precision
If single-crystalline silicon is used for the electrode plate, then etching uniformity is maintained, but production of large-diameter plates becomes difficult and costly
Solution Approach 1:
The single-crystal growth process is segmented into multiple regions, each nucleated from a separate seed crystal. This segmentation allows the production of large-diameter plates by combining multiple manageable single-crystal growth zones rather than attempting to grow one extremely large single crystal, thereby maintaining etching uniformity while improving manufacturability.
Solution Approach 2:
The invention changes the growth parameters by using multiple seed crystals simultaneously with controlled orientations, rather than attempting to grow one large crystal from a single seed. This parameter change enables large-diameter production while maintaining the single-crystal structure necessary for uniform etching.
3Volume of moving object
If multiple seed crystals are used to grow the columnar crystal silicon ingot, then large-diameter electrode plates can be produced, but crystal grain boundaries may form between the grown crystals
Solution Approach 1:
Each seed crystal region is maintained as a distinct single-crystal zone with controlled orientation and quality. The local quality of each segment is optimized independently during growth, ensuring that each region develops as a pure single-crystal structure without introducing grain boundaries at the interfaces between segments.
Solution Approach 2:
The multiple seed crystals are arranged and oriented to create equipotential growth conditions, where the solidification front advances uniformly across all seed crystal regions. This equipotential approach prevents the formation of crystal grain boundaries by ensuring continuous, coordinated growth without orientation mismatches between adjacent regions.
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
The approach results in high uniformity during plasma etching and reduces particle formation and device failures, achieving performance equivalent to single-crystalline silicon while minimizing crystal grain boundary-related issues, with specific oxygen and nitrogen concentration controls further enhancing etching rates.
Implementation Method 1
growing a single-crystal from each of seed crystals
Data Source
Figure 1
Figure 2A~3B
Figure 4A~5
AI summary
A silicon member for a semiconductor apparatus is provided. The silicon member has an equivalent performance to one fabricated from a single-crystalline silicon even though it is fabricated from a unidirectionally solidified silicon. In addition, it can be applied for producing a relatively large-sized part. The silicon member is fabricated by sawing a columnar crystal silicon ingot obtained by growing a single-crystal from each of seed crystals by placing the seed crystals that are made of a single-crystalline silicon plate on a bottom part of a crucible and unidirectionally solidifying a molten silicon in the crucible.