Fortrend Engineering Corporation

Fortrend Engineering Coirporation

Eric Meyhofer

Kenneth Alan Hardy

Cyril M Kindt

Torben J Ulander

Torben J H Ulander

William E Wegener

Steven A Bumgardner

Jeffrey M Gordon

An apparatus for determining the presence or absence of wafers in a cassette, i.e. a wafer mapper, is integrated with a door assembly in a load port interface that separates a process environment from an operator environment. In one orientation, a port cover plate seals an opening that pierces a bulkhead, while a door panel rests horizontally on the operator environment side of the bulkhead. In this position, a cassette of wafers may be placed on an inside surface of the door panel, with the top of the stack being open. As the door rotates to a vertical position, the wafer stack moves through the bulkhead opening thereby entering the process environment. A moveable trolley, connected to or within the door, moves parallel to the wafer stack detecting the presence of wafers by sensing light scattered from wafer edges through a window in a cover plate of the door panel. In this way the apparatus determines each wafer's location and may provide that information to subsequent wafer manufacturing operations. A movable air jet on a side of the window opposite the trolley, magnetically coupled to the trolley, moves with the trolley to clear liquid droplets or particles from the process environment side of the window.

Load port door assembly with integrated wafer mapper

A load port interface for determining the presence or absence of wafers in a cassette, i.e. a wafer mapper, is integrated with a port closure assembly in a load port interface separating a process environment from an operator environment. A cover plate and a door are arranged in an L-shape, with both members being able to seal the port in a bulkhead of the load port interface. In one configuration, the cover plate seals the port, while door panel members rest horizontally on the operator side of the bulkhead. In this position, a wafer stack, W, inside of a cassette may be placed on the inside door panel, with the top of the wafer stack, W, being open. As the door is raised from the horizontal position to a vertical position, the wafer stack, W, is rotated through an opening in the bulkhead so that the wafer stack, W, is now on the process side. The wafer mapper features a moveable trolley connected to, or within, the door. The trolley can move parallel to the wafer stack, W, under control of a stepper motor and examine each row of the stack, counting wafers as light is reflected or scattered from the edges of the wafers. Each wafer may be optically probed through a window in a cover plate and characteristic signals may be plotted to provide subsequent wafer manufacturing operations with wafer locations. A movable air knife on a side of the window opposite the trolley is magnetically coupled to the trolley and is moved together with the trolley in order to clear the window of liquid droplets from the process environment. When the load port interface positions the cassette and wafer stack, W, in the process environment, a fine spray of liquid droplets may be directed about the wafer stack, W.

A load port interface (20) receives, opens and closes a wafer carrier (22). A bulkhead (24) carries a changeable mating plate (92) that is pierced by a window (94). Changing the mating plate (92) adapts the load port interface (20) for use with different sizes of carriers(22). A table (32) of the load port interface (20) receives the carrier (22), advances the carrier (22) until it abuts and seals to the bulkhead (24). An end-effector (42), located on an opposite side of the bulkhead (24) from the carrier (22), actuates latch keys (54) to unlatch a door (48) from the carrier (22). The load port interface (20) then moves the unlatched door (48) rectilinearly, first horizontally away from the bulkhead (24) and then vertically downward, to expose semiconductor wafers (48) present within the carrier (22). The end-effector (42) includes sensors (86, 104) for collecting data about wafers (82) within the carrier (22) by detecting edges (118) thereof. This data is analyzed to determine the arrangement of wafers (82) within the carrier (22).

Wafer-mapping load post interface having an effector position sensing

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Palo Alto, CA, United States of America

Eric Meyhofer