Automatic wafer feeding and pre-alignment apparatus and method

A method of pre-aligning wafers prior to mask alignment or like treatment thereof without manual handling, comprising,

• A. feeding generally circular wafers in sequence from a supply thereof, each of which includes a flat edge portion, to a buffer station adjacent a pre-alignment station,
• B. providing reading means at said pre-alignment station capable of determining automatically when the flat edge portion of each wafer is in a predetermined orientation,
• C. providing additional wafers in sequence at said buffer station adjacent said pre-alignment station when such station is unoccupied,
• D. initiating rotation of each said wafer during introduction of the same in sequence into said pre-alignment station from said buffer station,
• E. continuing rotation of each said wafer at said pre-alignment station beneath said reading means until said reading means senses each such wafer is in said predetermined orientation and then halting rotation thereof, and
• F. maintaining the predetermined orientation of each said wafer while transferring the same to a mask alignment station from said pre-alignment station.

An apparatus for pre-aligning wafers prior to mask alignment or other treatment thereof, comprising

• A. means for presenting individual wafers in sequence to a pre-alignment station, each such wafer including a flat portion for use in such pre-alignment,
• B. means at said pre-alignment station for rotating each said wafer at said station,
• C. reading means at said station for determining automatically when the flat edge portion of each said wafer is in a predetermined orientation,
• D. said means for rotating wafers at said pre-alignment station, comprising
• 1. a pre-alignment chuck member having directional fluid passages therethrough,
• 2. such wafers being positionable in sequence on said chuck member, and
• 3. means for selectively introducing fluid through said passages to rotate each wafer presented onto said chuck member without manual handling until the flat edge portion of each such wafer is sensed by said reading means and rotation thereof is halted, and
• E. means responsive to said reading means to automatically halt rotation of each such wafer when the same is in said predetermined orientation.

In combination in an apparatus for pre-aligning wafers prior to mask alignment or like treatment thereof, comprising

• A. a magazine at a sender station having therein a supply of generally circular wafers each of which includes a flat edge portion for use in pre-alignment thereof;
• B. transfer means for receiving individual wafers in sequence from said supply magazine and for transferring the same to a pre-alignment station,
• C. means at said pre-alignment station to which said wafers are sequentially delivered by said transfer means for controllably rotating each said wafer at said station, comprising
• 1. a pre-alignment chuck member having directional fluid flow passages therethrough, and
• 2. means for selectively introducing and withdrawing fluid through said passages to alternately raise and lower each wafer presented thereto and to effect rotation thereof without manual handling until the flat edge portion of each such wafer is sensed by a reading means and rotation thereof is halted,
• D. reading means at said pre-alignment station for determining automatically when the flat edge portion of each said wafer is in predetermined orientation,
• E. means responsive to said reading means to halt rotation of each such wafer when the same is in said predetermined orientation, and
• F. means for moving each said pre-aligned wafer from said pre-alignment station to a mask aligning station adjacent said pre-alignment station while maintaining said predetermined orientation of each said wafer during such movement.

In combination in an apparatus for pre-aligning wafers prior to mask alignment or like treatment thereof, comprising

• A. a magazine at a sender station having therein a supply of generally circular wafers each of which includes a flat edge portion for use in pre-alignment thereof,
• B. transfer means for receiving individual wafers in sequence from said supply magazine and for transferring the same to a pre-alignment station,
• C. means at said pre-alignment station to which said wafers are sequentially delivered by said transfer means for controllably rotating each said wafer at said station,
• D. means at a buffer station adjacent said pre-alignment station for maintaining a wafer in position ready for movement into said pre-alignment station when said station is empty, comprising
• 1. fluid bearing track structure in communication with said transfer means which introduces successive wafers into said pre-alignment station and initiates rotation thereof as the same are introduced into said pre-alignment station,
• E. reading means at said pre-alignment station for determining automatically when the flat edge portion of each said wafer is in predetermined orientation,
• F. means responsive to said reading means to halt rotation of each such wafer when the same is in said predetermined orientation, and
• G. means for moving each said pre-aligned wafer from said pre-alignment station to a mask aligning station adjacent said pre-alignment station while maintaining said predetermined orientation of each said wafer during such movement.

An apparatus for pre-aligning wafers prior to mask alignment or other treatment thereof, comprising

• A. means for presenting individual wafers in sequence to a pre-alignment station, each such wafer including a flat edge portion for use in such pre-alignment,
• B. fluid bearing track structure for introducing wafers in sequence into said pre-alignment station, including means to initiate rotation of each wafer during introduction thereof to said station, and for withdrawing wafers in sequence from said station,
• C. means at said pre-alignment station for continuing rotation of each said wafer at said station,
• D. reading means at said station for determining automatically when the flat edge portion of each said wafer is in a predetermined orientation, and
• E. means responsive to said reading means to automatically halt rotation of each such wafer when the same is in said predetermined orientation.