Use of buffer members during growth of single crystal silicon ingots
AssigneeGlobalWafers Co., Ltd.
InventorsMatteo Pannocchia, Francesca Marchese, James Ho Wai Kitt
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Abstract
Methods for producing single crystal silicon ingots by Continuous Czochralski (CCz) are disclosed. A batch of buffer members (e.g., quartz cullets) is added to an outer melt zone of the crucible assembly before the main body of the ingot is grown. In some embodiments, the ratio of the mass M of the batch of buffer members added to the melt to the time between adding the batch of buffer members to the melt and when the ingot main body begins to grow is controlled such that the ratio of M/T is greater than a threshold M/T.
Claims16
A method for growing a single crystal silicon ingot in a continuous Czochralski process, the method comprising:
- forming a melt of silicon in a crucible assembly;
- adding a batch of quartz cullets to the melt, the batch having a mass M;
- contacting a surface of the melt with a seed crystal;
- withdrawing the single crystal silicon ingot from the melt, the single crystal silicon ingot comprising a main body, there being a time T between adding the batch of quartz cullets to the melt and start of growth of the main body;
- controlling the ratio of M/T to be greater than a threshold M/T to reduce void counts in wafers sliced from the single crystal silicon ingot;
- and
- adding solid polycrystalline silicon feedstock to the crucible assembly while withdrawing the single crystal silicon ingot to replenish the melt.
Dependencies are inferred from the claim text.