U.S. patent application number 12/010040 was filed with the patent office on 2008-05-22 for article transfer system.
Invention is credited to Eran Dvir, Beniamin Shulman.
Application Number | 20080115614 12/010040 |
Document ID | / |
Family ID | 32587612 |
Filed Date | 2008-05-22 |
United States Patent
Application |
20080115614 |
Kind Code |
A1 |
Dvir; Eran ; et al. |
May 22, 2008 |
Article transfer system
Abstract
A system for controlling an axial movement of an article is
presented. The system comprises a support stage assembly and a
spring suspension arrangement mounted on the support stage
assembly. The spring suspension arrangement comprises first and
second assemblies arranged in a coaxial relationship one inside the
other. The first assembly is attached to the support stage
assembly. The second assembly serves for supporting an
article-carrying member and is driven for movement along the axis
with respect to the first assembly. The outer one of the first and
second assemblies is configured to define two spaced-apart parallel
planes perpendicular to said axis. The first and second assemblies
are attached to each other by first and second membrane-like
members arranged in a spaced-apart parallel relationship along said
axis.
Inventors: |
Dvir; Eran; (Ramat Gan,
IL) ; Shulman; Beniamin; (Rehovot, IL) |
Correspondence
Address: |
Gary M. Nath;THE NATH LAW GROUP
112 South West Street
Alexandria
VA
22314
US
|
Family ID: |
32587612 |
Appl. No.: |
12/010040 |
Filed: |
January 18, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10647123 |
Aug 25, 2003 |
7320265 |
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12010040 |
Jan 18, 2008 |
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Current U.S.
Class: |
74/490.08 ;
74/490.07 |
Current CPC
Class: |
B23Q 1/58 20130101; Y10T
74/20354 20150115; G03F 7/70716 20130101; Y10T 74/20341 20150115;
H01L 21/68792 20130101; Y10T 74/20348 20150115; H01L 21/68
20130101; H01L 21/68785 20130101 |
Class at
Publication: |
074/490.08 ;
074/490.07 |
International
Class: |
G05G 11/00 20060101
G05G011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 5, 2003 |
IL |
156330 |
Claims
1. A system for controlling an axial movement of an article, the
system comprising: a support stage assembly; a spring suspension
arrangement mounted on said support stage assembly and comprising
first and second assemblies arranged in a coaxial relationship with
respect to the axis of the article movement, and one inside the
other, the first assembly being attached to said support stage
assembly and the second assembly serving for supporting an
article-carrying member and being driven for a movement along said
axis of the article movement with respect to the first assembly,
the outer one of the first and second assemblies being configured
to define two spaced-apart parallel planes perpendicular to said
axis, said first and second assemblies being attached to each other
by first and second membrane members arranged in a spaced-apart
parallel relationship along said axis, and a motor operable for
rotating said support stage around said axis, said motor being
located inside the inner one of said first and second
assemblies.
2. The system of claim 1, comprising a drive assembly associated
with said first assembly and operable to provide said movement
thereof along said axis.
3. The system of claim 1, wherein said outer assembly is attached
to the support stage assembly, and said inner assembly is driven
for movement along said axis.
4. The system of claim 1, wherein said outer assembly is composed
of at least three spaced-apart pin members kept at a fixed position
with respect to one another, and said inner assembly is composed of
at least one pin member.
5. The system of claim 4, wherein an arrangement of said at least
three fixed members of the outer assembly defines a regular
polygon, and the pin member of the inner assembly is located
substantially at the center of said polygon.
6. The system of claim 1, wherein the outer and inner assemblies
have the same height.
7. The system of claim 1, wherein said outer and inner assemblies
are configured as cylinders or prisms.
8. The system of claim 7, wherein the inner assembly at its top and
bottom is attached to the top and bottom of the outer assembly by
said first and second membrane members, respectively.
9. The system of claim 8, wherein said membrane members have
annular geometry.
10. The system of claim 8, wherein said membrane members are
clamped to the opposite sides of each of the outer and inner
assemblies via clamping rings.
11. The system of claim 7, wherein said inner assembly is driven
for said movement with respect to the outer assembly, said outer
assembly being attached to the support stage assembly.
12. The system of claim 1, comprising the article-carrying member
mounted on the second assembly for rotation with respect to said
second assembly, the system being thereby operable as a
Z-Theta-system.
13. The system of claim 1, wherein said support stage assembly is
driven for movement in a plane perpendicular to said axis.
14. The system of claim 13, wherein said support stage assembly is
driven for movement in a plane perpendicular to the Z-axis, the
system being thereby operable as a Z-R-Theta-system.
15. The system of claim 14 for use in transfer and positioning of a
disk article with respect to said axis, wherein the support stage
assembly is movable along a perpendicular axis for a distance of at
least a radius of the article.
16. The system of claim 1, wherein the article-carrying member is
mounted on a central axis of said second assembly by means of a
pair of spherical washers facing each other by their male and
female surfaces, respectively, thereby enabling precise positioning
of the article-carrying member in a plane perpendicular to said
axis.
17. The system of claim 2, wherein said drive assembly comprises a
mechanical pair formed by a roller bearing mounted on a tapered
surface of the wedge element; and a motor operable for moving the
wedge element along an axis perpendicular to said axis.
18. A system for controlling movement of an article along at least
a vertical axis and rotational movement of the article, the system
comprising: a support stage assembly; a spring suspension
arrangement mounted on said support stage assembly and comprising
first and second vertically oriented cylindrical assemblies
arranged in a coaxial relationship one inside the other, the first
assembly being attached to said support stage assembly and the
second assembly serving for supporting an article-carrying member
and being driven for movement along the vertical axis with respect
to the first assembly, the inner cylindrical assembly at its top
and bottom being attached to the top and bottom of the outer
cylindrical assembly by, respectively, first and second membrane
members thereby arranged in a spaced-apart parallel relationship
along the vertical axis, and a motor operable for rotating the
support stage, said motor being located inside said inner
assembly.
19. The system of claim 18, wherein said support stage assembly is
driven for movement along at least one horizontal axis.
20. A system for controlling movement of an article along the
Z-axis and in the horizontal X-Y-plane, the system comprising: a
support stage assembly driven for movement along X- and Y-axes; a
spring suspension arrangement mounted on said support stage
assembly and comprising first and second vertically oriented
cylindrical assemblies arranged in a coaxial relationship one
inside the other, the first assembly being attached to said support
stage assembly, and the second assembly serving for supporting an
article-carrying member and being driven for movement along the
vertical axis with respect to the first assembly, said
article-carrying member being driven for rotation in the horizontal
plane, the inner cylindrical assembly at its top and bottom being
attached to the top and bottom of the outer cylindrical assembly
by, respectively, first and second membrane members thereby
arranged in a spaced-apart parallel relationship along the vertical
axis, a motor operable for rotating the support stage in the
horizontal plane, said motor being located inside said inner
assembly.
Description
FIELD OF THE INVENTION
[0001] This invention relates to an article transfer system,
particularly useful in applications where precise positioning of an
article with respect to a processing or metrology tool is
required.
BACKGROUND OF THE INVENTION
[0002] Various applications, such as article inspection and
measurements, as well as lithography processing, require precise
movement of the article with respect to a processing tool along a
vertical axis (Z-axis). For example, in the manufacture of
semiconductor devices, as well as testing of circuits on
semiconductor wafers, the wafer is typically supported on a stage
mounted for a Z-axis movement (Z-stage) and sometimes also for
rotation (Z/Theta stage).
[0003] U.S. Pat. No. 5,150,040 discloses a dual mode Z/Theta stage
for supporting and moving a workpiece, such as a semiconductor
wafer, for positioning during testing. The Z/Theta stage has a
peripheral four-point elevator drive. The elevating suspension
comprises parallel, vertically oriented, rigid lift pins, which
bear the weight of a top-plate. The lift pins are located about the
periphery of the stage to provide stability of the support. The top
plate essentially floats on the lift pins so that virtually no
frictional forces are translated to lift pins. The lift pins are
elevated together by the force of four matched pin lift levers,
crank arms. The crank arms are driven by downward force from a
vertically translating air piston, which is in contact with the
crank arms. The air piston provides a gentle force moderated by
pneumatic pressure, which can moderate the full force of a stepping
motor that drives it.
SUMMARY OF THE INVENTION
[0004] There is a need in the art to facilitate processing of
articles by supporting an article on an article transfer system
enabling precise movement of the article along a vertical axis.
Here, the term "processing" signifies also measurement or
inspection of articles.
[0005] The system of the present invention has a simple
construction allowing precise movement of an article along a
vertical axis (Z-axis) within a limited range of distances, and
preferably also rotation of the article about the Z-axis.
[0006] The main idea of the present invention consists of utilizing
a spring suspension arrangement for supporting an article-carrying
member. The spring suspension arrangement is formed by two
assemblies arranged in a coaxial relationship, one inside the
other, wherein the outer assembly is configured to define two
spaced-apart parallel planes perpendicular to the vertical axis.
The arrangement is such that the first assembly is kept at a fixed
position, and the second assembly, which is intended for supporting
an article-carrying member, is driven for movement along a vertical
axis with respect to the first assembly, while the assemblies are
attached to each other by first and second membrane-like members
arranged in a spaced-apart parallel relationship along the vertical
axis. The vertical movement of the second assembly causes the
deformation of the membrane-like members, thereby limiting the
movement of the second assembly (and consequently the
article-carrying member) by the deformability of membranes.
[0007] Thus, according to a broad aspect of the present invention,
there is provided a system for controlling an axial movement of an
article, the system comprising: [0008] a support stage assembly;
[0009] a spring suspension arrangement mounted on said support
stage assembly and comprising first and second assemblies arranged
in a coaxial relationship one inside the other, the first assembly
being attached to said support stage assembly and the second
assembly serving for supporting an article-carrying member and
being driven for movement along said axis with respect to the first
assembly, the outer one of the first and second assemblies being
configured to define two spaced-apart parallel planes perpendicular
to said axis, said first and second assemblies being attached to
each other by first and second membrane-like members arranged in a
spaced-apart parallel relationship along said axis.
[0010] According to one embodiment of the invention, the outer
assembly is composed of at least three spaced-apart pin-like
members kept at a fixed position with respect to one another, and
the inner assembly is composed of at least one pin-like member.
According to another preferred embodiment of the invention, the
outer and inner assemblies are configured as cylinders or prisms,
of preferably substantially the same height. The inner assembly at
its top and bottom is attached to the top and bottom of the outer
assembly by said first and second membrane-like members,
respectively. The membrane-like members are preferably of annular
geometry, and may be clamped to the opposite sides of each of the
outer and inner assemblies via clamping rings.
[0011] According to another aspect of the invention, there is
provided a system for controlling movement of an article along at
least a vertical axis, the system comprising: [0012] a support
stage assembly; [0013] a spring suspension arrangement mounted on
said support stage assembly and comprising first and second
vertically oriented cylindrical assemblies arranged in a coaxial
relationship one inside the other, the first assembly being
attached to said support stage assembly and the second assembly
serving for supporting an article-carrying member and being driven
for movement along the vertical axis with respect to the first
assembly, the inner cylindrical assembly at its top and bottom
being attached to the top and bottom of the outer cylindrical
assembly by, respectively, first and second membrane-like members
thereby arranged in a spaced-apart parallel relationship along the
vertical axis.
[0014] According to yet another aspect of the invention, there is
provided a system for controlling movement of an article along at
least a vertical axis, the system comprising: [0015] a support
stage assembly; [0016] a spring suspension arrangement mounted on
said support stage assembly and comprising first and second
vertically oriented cylindrical assemblies arranged in a coaxial
relationship one inside the other, the outer cylindrical assembly
being attached to said support stage assembly and the inner
cylindrical assembly serving for supporting an article-carrying
member and being driven for movement along the vertical axis with
respect to the outer assembly, the inner cylindrical assembly at
its top and bottom being attached to the top and bottom of the
outer cylindrical assembly by, respectively, first and second
membrane-like members being thereby arranged in a spaced-apart
parallel relationship along the vertical axis, [0017] a drive
assembly associated with said inner cylindrical assembly and
operable to provide said movement thereof.
[0018] The article-carrying member mounted on the second assembly
may be driven for rotation with respect to said second assembly in
a plane perpendicular to said axis of movement of the second
assembly. The support stage assembly may be driven for movement in
a plane perpendicular to said axis of movement of the second
assembly. Considering a disk-like article, the support stage
assembly is preferably movable along at least one perpendicular
axis for a distance of at least a radius of the article The system
may thus be operable as a Z-Theta-stage, R-Z-Theta-stage or
X-Y-Z-Theta-stage.
[0019] Thus, according to yet another aspects of the invention,
there are provided an R-Theta-Z system and an X-Y-Theta-Z system
for controlling movement of an article including the
above-described spring suspension arrangement.
[0020] The system of the present invention has a simple (and low
cost) construction, which can be operable by a simple servo-control
mechanism and provides for smoothness of the article movement with
high precision. These features are of great importance for such
applications as processing/inspection/measurements of semiconductor
wafer structures. Generally, the system of the present invention
can advantageously be used in optical measurements (precise
focusing), electrical measurements (e.g., in four point probe
measurements), near field measurements (e.g., eddy current based
resistivity measurements), etc.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to understand the invention and to see how it may
be carried out in practice, a preferred embodiment will now be
described, by way of non-limiting example only, with reference to
the accompanying drawings, in which:
[0022] FIGS. 1A and 1B schematically illustrate the main
constructional and operational principles of an article transfer
and positioning system according to the invention, where FIG. 1A
shows the system in an initial, non-deformated state of membranes
of a spring suspension arrangement, and FIG. 1B shows the system in
an operative state with the membranes being deformated.
[0023] FIG. 2 exemplifies a specific implementation of the system
of the present the invention;
[0024] FIG. 3 more specifically illustrates a part of the system of
FIG. 2 configured to provide rotation of an article supporting
element about the Z-axis; and
[0025] FIG. 4A schematically illustrates a Z-R-Theta-system of the
present invention; and
[0026] FIG. 4B shows an exploded view of the Z-R-Theta-system of
FIG. 4A.
DETAILED DESCRIPTION OF THE INVENTION
[0027] The present invention provides an article transfer and
positioning system configured and operable to enable precise
movement of the article along a vertical axis (Z-axis), and
preferable also rotation about the Z-axis.
[0028] FIGS. 1A and 1B schematically illustrate the main
constructional and operational principles of a system 10 according
to the invention. The system 10 includes such main constructional
parts as a support stage assembly 12 and a spring arrangement 11
mounted on the support stage assembly 12. The stage 12 may be
driven for movement in a horizontal plane, presenting the so-called
X-Y-stage or alternatively R-Theta stage.
[0029] The spring arrangement 11 includes inner and outer
assemblies 14A and 14B, wherein one of these assemblies--the outer
assembly 14A in the present example--is attached to the stage 12
and define upper and lower horizontal planes P.sub.1 and P.sub.2.
The other assembly--inner assembly 14B in the present example--is
attached to the assembly 14A in a manner to be vertically movable
with respect to the assembly 14A within a limited range of
distances. This is achieved by attaching the assemblies 14A and 14B
to each other via two membrane-like members M.sub.1 and M.sub.2.
Thus, driving of the inner assembly 14B for movement along the
Z-axis would result in the simultaneous deformation of the
membranes M.sub.1 and M.sub.2 (FIG. 1B), the limits of the
Z-movement being defined by the deformability of the membranes and
their dimensions. As shown in the figure in dashed lines, an
article-carrying member 18 is mounted on the inner assembly 14B,
and would thus be movable together with the assembly 14B. The
membranes are preferably identical and are centered at the central
axis CA of the inner assembly 14B.
[0030] It should be understood that, alternatively, the same effect
could be achieved by attaching the inner assembly 14B to the stage
12, rather than the outer assembly 14A, and driving the outer
assembly 14A for movement along the Z-axis in a similar manner.
[0031] Driving of the inner assembly 14B (or outer assembly, as the
case may be) along the Z-axis can generally be achieved by
associating this assembly with any suitable linear driver 20.
[0032] It should also be understood that, generally, in order to
define the upper and lower planes for the membranes' location (in
their non-deformable position), the outer assembly 14A can be
formed by at least three spaced-apart members (e.g. rods or struts)
N.sub.1-N.sub.3, preferably arranged so as to form a regular
polygon (equilateral triangle in the present example) that are
fixed to the stage 12 and are kept at a fixed position with respect
to one another. As for the inner assembly, it may be in the form of
a member (e.g. rod-shaped) N.sub.4 located at the center of this
polygon. Preferably, the assemblies 14A and 14B are configured as
outer and inner prisms or cylinders.
[0033] Referring to FIG. 2, there is illustrated a specific, but
non-limiting, example of implementation of a system 100 according
to the invention for use in transferring and positioning of
articles. The system 100 is configured as a Z-stage, and preferably
also as an R-Theta-stage. The system 100 comprises a spring
suspension arrangement 110 mounted on a stage assembly 112. The
stage 112 can be mounted for movement in a horizontal plane along
one or two perpendicular axes (X-Y plane), i.e., presents an
X-stage.
[0034] The spring arrangement 110 is formed by outer and inner
cylinder-like assemblies (drums) 114A and 114B. The outer drum 114A
is formed with openings, generally at 115, the provision of which
is optional and is aimed at decreasing the weight of the entire
construction and also at allowing access to the inner parts of the
construction (e.g., for maintenance purposes). The drums 114A and
114B are attached to each other by top and bottom membrane-like
members M.sub.1 and M.sub.2 (for example made of a stainless steel
and having a thickness of 0.5 mm). The membranes M.sub.1 and
M.sub.2 have an annular shape and are clamped to the drums by means
of clamping rings 117A and 117B, respectively, and bolts 119A and
119B.
[0035] Further provided in the system 100 is a drive assembly 116
configured and operated for providing a movement of the drum 114B
along the Z-axis. In the present example, the drive assembly 116
comprises a mechanical pair formed by a roller bearing 116A mounted
on a central axis (shaft) CA of the inner drum 114B and a wedge
element 116B supporting the bearing 116A on its inclined surface. A
linear motor 116C is provided being connected to the wedge element
116B for moving it along the X-axis. Thus, when the wedge 116A is
driven for a back and forward movement along the X-axis, the roller
bearing 116B drives the inner assembly 114B for movement along the
Z-axis. The inner drum 114B serves for supporting an article
holding assembly 118. In the present example, where
measurements/inspection/processing of semiconductor wafers is
considered, the wafer supporting assembly 118 includes a chuck unit
120 preferably mounted for rotation in the horizontal plane.
Considering rotation of the chuck carrying a disk-like article
(e.g., semiconductor wafer), the stage 112 is movable along the
X-axis within the range defined by the radius of the article (of at
least the wafer's radius). The system 100 thus presents the
Z-R-Theta stage. It should be understood that, generally, the
system 100 might utilize X-Y-movement of the stage 112 with and
without a rotation of the chuck unit 120.
[0036] FIG. 3, which is a cross-sectional view of a part of the
system 100, more specifically illustrates the chuck unit 120
mounted on the inner drum 114B. As shown, the chuck unit 120 is
mounted on a rotor-part 124A of a motor 124, whose stator-part 124B
is attached to the inner drum 114B. As further shown in FIGS. 2 and
3, the chuck unit 120 is mounted on a shaft of the rotor-part 124A
via a pair of spherical washers 125A (male) and 125B (female)
facing each other by their concave and convex surfaces and a bolt
126, e.g. spherical washers DIN 6319 commercially available from
Ganter Griff. While mounting the chuck, its precise horizontal
positioning can be regulated by displacing the washers with respect
to each other.
[0037] Reference is now made to FIGS. 4A and 4B showing the entire
construction of the system 100 being used for supporting an
article, e.g., wafer W (300 mm diameter). The configuration of the
system 100 presents an accurate R-Theta-Z-system that can be
operable as an integrated or stand-alone wafer stage platform. In
the present example, the system 100 is used for auto-focusing
purposes to control the wafer's in-focus position relative to an
optical measuring module located above the wafer (not shown).
[0038] Wafer W is hold by a buffer unit (frame) 130. The
construction and operation of the buffer unit 130 does not form a
part of the present invention and therefore need not be
specifically described. The preferred implementation of the buffer
unit 130 is disclosed in co-pending U.S. application Ser. No.
10/232,384 assigned to the assignee of the present application. The
buffer unit 130 is mounted on the stage 112 and associated with a
drive mechanism (not shown) to be movable along the Z-axis with
respect to the stage 112, and consequently with respect to the
chuck unit 120, which is mounted on the inner drum 114B of the
spring suspension arrangement. The chuck 120 is typically provided
with openings for vacuum holding of the wafer. Considering the use
of such a buffer unit for gripping and holding a wafer (load/unload
station), the diameter of the chuck 120 is smaller than the
diameter of the wafer. The chuck 120 is movable along the Z-axis
(due to the movement of the drum of spring suspension arrangement)
within a 1 mm-distance at a 0.1 .mu.m precision, and is 360-degree
rotatable. In the present example, also mounted on the stage 112 is
an optical system 132 serving as the so-called "notch finder" for
identifying a wafer located on the chuck and/or providing angular
positioning of the wafer with respect to a processing tool
(measurement, inspection, etc. tool).
[0039] Those skilled in the art will readily appreciate that
various modifications and changes can be applied to the embodiments
of the invention as hereinbefore described without departing from
its scope as defined in and by the appended claims.
* * * * *