Method for detecting imperfect mounting of a rod-shaped metallic object in a metallic hollow shaft and a device
AssigneeTexas Instruments Incorporated
InventorsWolfgang Pfeiffer, Thomas Klein
Life of this patent
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Abstract
A method for detecting an imperfect mounting of an essentially rod-shaped metallic object in a metallic hollow shaft is provided. The imperfect mounting may lead to the formation of metallic particles. The rod-shaped object is mounted electrically insulated from the hollow shaft. The electrical resistance between the rod-shaped object and the hollow shaft is measured. An alert is issued when the electrical resistance is lower than a predefined level. A device includes a spin unit with a hollow drive shaft and a nozzle mounted inside the hollow shaft. The device is configured to use the inventive method.
Claims6
A method for cleaning a wafer, comprising the steps of:
- inserting a nozzle through a hollow drive shaft;
- placing an insulator structure between the nozzle and the hollow drive shaft such that the nozzle is electrically insulated from the hollow drive shaft;
- placing a wafer in a wafer cup connected to the hollow drive shaft;
- spinning the wafer by rotating the hollow drive shaft without rotating the nozzle;
- directing a liquid through the nozzle and onto the wafer while spinning the wafer;
- measuring the electrical resistance between the nozzle and the hollow drive shaft;
- and
- issuing an alert when the electrical resistance is lower than a predefined level.
A system for cleaning a wafer, comprising:
- a hollow drive shaft;
- a nozzle inserted through the hollow drive shaft;
- an insulator structure between the nozzle and the hollow drive shaft such that the nozzle is electrically insulated from the hollow drive shaft;
- a wafer cup connected to the hollow drive shaft such that the wafer cup and the hollow drive shaft are operable to be rotated without rotating the nozzle;
- a motor connected to the hollow drive shaft, the motor and hollow drive shaft connected to ground;
- a measurement unit connected to the nozzle and to ground to measure the electrical resistance between the nozzle and the hollow drive shaft and generate a signal when the electrical resistance is lower than a predefined level.
Dependencies are inferred from the claim text.