| 摘要 |
This invention relates to methods and apparatus for delivering liquid precursors to semi-conductor processing apparatus. The liquid precursor delivery system is generally indicated at 10 and includes a source 11, an inlet tube 12, a two-way valve 13, a pump assembly 14, an outlet tube 15, a shut-off valve 16 and a flash evaporator 17. The pump assembly 14 is in the form of a syringe or variable volume pump and is controlled by a combination of a step motor 27 and a linear encoder 30. The arrangement is such that unused liquid precursor can be returned to the source.
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