Dynamic chuck for semiconductor wafer or other substrate

Details Dynamic chuck for semiconductor wafer or other substrate Dynamic chuck for semiconductor wafer or other substrate

1999-02-09

2001-01-02

Stinson, Frankie L. (Department: 1746)

Cleaning and liquid contact with solids

Apparatus

With means to movably mount or movably support the work or...

C134S153000, C134S902000, C034S058000, C414S941000

Utility Patent

active

06167893

ABSTRACT:

BACKGROUND OF THE INVENTION
Semiconductor wafers and other substrates are frequently subjected to high-speed spinning when they are rinsed or dried. During the spinning operation the wafer must be properly centered, with its center of gravity at or very near the axis of rotation. The wafer must also be held securely, to prevent any disparity between its center of gravity and the axis of rotation from causing the wafer to be thrown outward by centrifugal force. This is particularly the case as the speed of rotation increases.
Most wafer holding systems are either passive or active. That is, either the wafer rests in or on the supporting surface (frequently referred to as a “chuck”) or some type of mechanism or force system is used to hold the wafer in place. Example of such mechanisms and systems are mechanical grippers and vacuum clamps. Passive systems generally require that the wafer be placed on the chuck with great precision. While this can normally be done where the wafers are manually loaded, it is difficult to consistently load the wafers in the proper position with automatic, robot-operated systems.
SUMMARY
A dynamic chuck according to this invention includes a wafer supporting member and a plurality of pivotable clamping arms. Each of the clamping arms is pivotable about a horizontal axis of rotation located below a wafer supported on the supporting member. Each of the clamping arms has a center of gravity located below the axis and a holding surface located above said axis for contacting a peripheral edge of said wafer.
In one embodiment according to this invention, three pivotable clamping arms are mounted, respectively, on three beams which extend radially from a vertical axis about which the wafer rotates. The wafer is supported on three support pins positioned, respectively, near the ends of the beams such that the support pins make contact with a peripheral region of the bottom surface of the wafer. Tapered guide pins also positioned near the ends of the beams provide surfaces for guiding the wafer to an approximate position on the support pins. The beams are connected to a spin motor which rotates the chuck and the wafer about the vertical axis during rinsing and/or drying operations.
Since the center of gravity of each clamping arm is located below its horizontal axis of rotation, as the chuck is rotated the upper portions of the clamping arms are urged inward and grip the edge of the wafer. The pressure exerted by each clamping arm against the wafer is a function of, among other things, the distance between the center of gravity and axis of rotation of the clamping arm and the speed of rotation of the radial beams.
This invention also includes a method which comprises positioning a semiconductor wafer between a plurality of clamping arms, each of the clamping arms being positioned equidistant from a vertical axis of rotation of the wafer and being rotatable about a horizontal axis, and each of the clamping arms having a center of gravity which is spaced apart from the horizontal axis of rotation; and causing the clamping arms to revolve about the vertical axis of rotation such that a centrifugal force acting on each of the clamping arms causes each of the clamping arms to rotate about the horizontal axis and thereby causes a holding surface on each of the clamping arms to exert a force against an edge of the wafer.
The relative positions of the center of gravity and horizontal axis of rotation of each clamping arm also assures that the clamping arms will pivot to an open position when the chuck is not rotating about its vertical axis.
A dynamic wafer chuck according to this invention allows a wide positioning tolerance when a wafer is placed on the chuck and eliminates the need for precise wafer position sensing before cleaning, rinsing and spin-drying the wafer.


REFERENCES:
patent: 4724619 (1988-02-01), Poli et al.
patent: 4788994 (1988-12-01), Shinbara
patent: 5421056 (1995-06-01), Tateyama et al.
patent: 5445172 (1995-08-01), Thompson et al.
patent: 5566466 (1996-10-01), Hearne
patent: 5666985 (1997-09-01), Smith, Jr. et al.
patent: 5715610 (1998-02-01), Smith, Jr. et al.
patent: 5775000 (1998-07-01), Maekawa et al.
patent: 5954072 (1999-09-01), Matusita

Affiliated with

Also associated with

Rating

Dynamic chuck for semiconductor wafer or other substrate does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Dynamic chuck for semiconductor wafer or other substrate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamic chuck for semiconductor wafer or other substrate will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2480096