Polycrystalline Silicon Packaging Method for Carbon Impurity Reduction
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Solution Overview
Problem
Conventional packaging methods for polycrystalline silicon lumps fail to adequately address the issue of surface contamination due to organic impurities, particularly carbon impurities, during the heat-sealing process, which can affect the quality of semiconductor devices and solar cells.
Innovation Solution
A packaging method where the packaging bag is clamped to prevent gas from flowing into the filling part during heat-sealing, with the heat-seal part being sealed by sealing rods and the clamping rods positioned to minimize gas flow, and the excess length part being bent to prevent gas adhesion on the polycrystalline silicon, and a double-packaging method using two bags to further reduce contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat-sealing is performed to seal the packaging bag, then the sealing reliability is improved, but surface contamination by carbon impurities increases
Solution Approach 1:
The heat-sealing process is divided into two stages: first sealing the packaging bag at a position away from the polycrystalline silicon, then sealing the excess length part separately. This segmentation prevents direct contact between generated gas and the silicon surface while maintaining sealing reliability.
Solution Approach 2:
The packaging bag material acts as an intermediary barrier between the heat-sealing process and the polycrystalline silicon. By sealing the bag rather than directly contacting the silicon, the harmful gas is contained within the bag material, preventing contamination of the silicon surface.
2Ease of operation
If the packaging bag is sealed without clamping, then the ease of operation is improved, but gas flows into the filling part causing contamination
Solution Approach 1:
The clamping rods are positioned in advance at a location away from the polycrystalline silicon before heat-sealing begins. This preliminary positioning ensures that when gas is generated during sealing, it is already contained within the sealed region, preventing it from reaching the silicon.
Solution Approach 2:
The harmful gas is extracted and contained within the sealed packaging bag region, separating it from the filling part containing the polycrystalline silicon. The clamping rods create a physical barrier that extracts the gas path from the filling area.
3Ease of manufacture
If the excess length part is left straight, then the ease of manufacture is improved, but gas adhesion on the polycrystalline silicon increases
Solution Approach 1:
The excess length part is bent into a curved configuration rather than remaining straight. This curvature changes the gas flow pattern and prevents direct adhesion of generated gas to the polycrystalline silicon surface, while still maintaining packaging integrity.
Solution Approach 2:
The excess length part is bent in a direction away from the polycrystalline silicon, moving the potential gas adhesion area to a different spatial dimension. This dimensional change ensures that even if gas is generated, it does not contact the silicon surface.
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
Significantly reduces surface contamination of polycrystalline silicon by minimizing gas adhesion and ensuring that generated gases are adsorbed within the packaging bag, thereby improving the quality of both the polycrystalline silicon and the monocrystalline silicon produced from it.
Implementation Method 1
in a state in which a part closer to an opening side of the packaging bag than the filling part is clamped by clamping rods so as not to flow gas into the filling part
Implementation Method 2
the planned heat-seal part is heat-sealed by sealing rods
Implementation Method 3
the excess length part is bent so as not to adhere gas on the polycrystalline silicon
Implementation Method 4
ensuring that generated gases are adsorbed within the packaging bag
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
This packaging method for polycrystalline silicon is for reducing contamination by surface organic impurities, in particular surface carbon impurities. After a packaging bag is filled with polycrystalline silicon, a portion of the packaging bag on the opening part side relative to a filled part where the polycrystalline silicon is filled and on the filled part side relative to a planned heat-seal part where the packaging bag will be heat-sealed is clamped by clamping rods such that no gas flows into the filled part, the planned heat-seal part is heat-sealed by sealing rods on both sides while clamped by the clamping rods, and the clamping rods are removed after the heat-sealing.