Method and apparatus for polishing semiconductor wafers
AssigneeLam Research Corporation
InventorsEdward T. Ferri JR., Randall L. Green, Anil K. Pant
Life of this patent
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Abstract
A system and method for planarizing a plurality of semiconductor wafers is provided. The method includes the steps of processing each wafer along the same process path using at least two polishing stations to each partially planarize the wafers. The system includes an improved process path exchanging a detachable wafer carrying head with spindles at each processing point and conveying the detached wafer carrying heads in a rotary index table between processing points. The system also provides for improved polishing accuracy using linear polishers having pneumatically adjustable belt tensioning and aligning capabilities.
Claims51
A method for uniformly planarizing and cleaning a surface of at least one semiconductor wafer comprising the steps of:
- providing a semiconductor wafer and a semiconductor wafer polishing system;
- mounting the semiconductor wafer in a wafer holder on the semiconductor wafer polishing system;
- transporting the semiconductor wafer from the wafer holder to a wafer conveyor loading device in the semiconductor polishing system;
- transferring the semiconductor wafer from the wafer conveyor loading device to a wafer conveyor and transporting the semiconductor wafer to a first primary polishing station;
- performing a first polishing procedure to partially planarize the surface of the semiconductor wafer;
- transporting the semiconductor wafer on the wafer conveyor to a second polishing station;
- and
- performing a second polishing procedure to complete planarization of the semiconductor wafer.
A method of efficiently and uniformly planarizing a semiconductor wafer comprising the steps of:
- providing a plurality of semiconductor wafers;
- providing a wafer polishing apparatus having a plurality of polishing stations positioned around a semiconductor wafer conveyor;
- a) transferring a semiconductor wafer to the semiconductor wafer conveyor;
- b) moving the semiconductor wafer to a first of the plurality of polishing stations;
- c) removing the wafer from the semiconductor wafer conveyor;
- d) polishing the semiconductor wafer at the first polishing station for a set time period;
- e) transferring the wafer to the wafer conveyor;
- f) moving the semiconductor wafer to a next one of the plurality of polishing stations;
- g) removing the wafer from the wafer conveyor;
- h) polishing the semiconductor wafer at the next polishing station for the set time period;
- and
- i) repeating steps e) through h), wherein the set time period equals a predetermined total polishing time divided by a total number of the plurality of polishing stations.
A method of transporting a semiconductor wafer between a wafer conveyor and each of a plurality of wafer processing stations in a wafer polishing system comprising the steps of:
- placing a semiconductor wafer onto a wafer holding head, the wafer holding head removably mounted on a rotatable, axially movable spindle;
- moving the wafer holding head to a wafer head retainer on the wafer conveyor;
- disengaging the wafer holding head from the spindle and releasably locking the wafer holding head to the wafer conveyor;
- moving the wafer conveyor so that the wafer holding device moves to a wafer processing station;
- removing the wafer holding head from the wafer head retainer and transporting the wafer holding head from the wafer conveyor to the wafer processing station;
- and
- processing the wafer at the wafer processing station.
An apparatus for performing chemical mechanical planarization of a plurality of semiconductor wafers implementing a single process path for each of the plurality of semiconductor wafers, the apparatus comprising:
- a wafer conveyor having a plurality of wafer receiving areas, the wafer conveyor movable to receive a semiconductor wafer in each of the plurality of wafer receiving areas from a wafer conveyor loading device and sequentially move each of the plurality of semiconductor wafers along a process path;
- a first polishing station positioned along the process path for planarizing a semiconductor wafer over a predetermined time to produce a partly planarized semiconductor wafer;
- and
- a second polishing station positioned along the process path, the second primary polishing station designed to planarize the partly planarized semiconductor over the predetermined time to produce a fully planarized semiconductor wafer, whereby each of the plurality of semiconductor wafers travels the process path via the wafer conveyor and each of the plurality of semiconductor wafers is planarized on both the first and second primary polishing stations.
The apparatus of claim 13 further comprising a third polishing station positioned along the process path to receive the fully planarized semiconductor wafer from the wafer conveyor, the third polishing station for removing residual scratches and polishing fluid from the fully planarized wafer.
A semiconductor wafer transfer mechanism for transporting a semiconductor wafer between a wafer conveyor and a wafer processing point, the transfer mechanism comprising:
- a rotatable, axially movable spindle;
- a lever arm attached to the spindle having a first end connected to a movable frame and a second end connected to a fine adjustment spindle driver, the fine adjustment spindle driver attached to the movable frame;
- a coarse adjustment spindle driver attached to a fixed frame and connected to the movable frame, wherein the coarse adjustment spindle drive is adapted to move the movable frame relative to the fixed frame in an axial direction of the spindle.
A wafer polishing station for performing chemical mechanical planarization of a semiconductor wafer using an abrasive polishing agent, the wafer polishing station comprising:
- a polishing member movable in a linear direction with respect to a surface of the semiconductor wafer;
- a polishing member drive assembly for moving the polishing member in the linear direction;
- and
- a pneumatic steering and tension adjustment mechanism for controlling operation of the polishing member.
A wafer conveyor loading apparatus for loading and unloading semiconductor wafers from a wafer conveyor, the wafer conveyor loading device comprising:
- a rinse containment tub positioned adjacent the wafer conveyor, the rinse containment tub having an open end and a closed end, the open end oriented toward the wafer conveyor, the rinse containment tub movable relative to the wafer conveyor;
- a wafer receiving area sized to receive a semiconductor wafer, the wafer receiving area movably connected to the rinse containment tub and positioned coaxially relative to a vertical axis of the rinse containment tub;
- and
- at least one spray nozzle positioned within the rinse containment tub for rinsing a semiconductor wafer.
An apparatus for performing chemical mechanical planarization of a plurality of semiconductor wafers implementing a single process path for each of the plurality of semiconductor wafers, the apparatus comprising:
- a wafer conveyor having a plurality of wafer receiving areas, the wafer conveyor movable to receive a semiconductor wafer in each of the plurality of wafer receiving areas from a wafer conveyor loading device and sequentially move each of the plurality of semiconductor wafers along a process path;
- a first polishing station positioned along the process path for planarizing a semiconductor wafer over a predetermined time to produce a partly planarized semiconductor wafer;
- a second polishing station positioned along the process path, the second primary polishing station designed to planarize the partly planarized semiconductor over the predetermined time to produce a fully planarized semiconductor wafer;
- a third polishing station positioned along the process path to receive the fully planarized semiconductor wafer from the wafer conveyor, the third polishing station for removing residual scratches and polishing fluid from the fully planarized wafer;
- and
- a central controller electrically connected to the wafer conveyor, the first, second and third polishing stations, wherein the central controller manages processing of the plurality of semiconductor wafers along the process path.
Dependencies are inferred from the claim text.