U.S. patent application number 11/172922 was filed with the patent office on 2005-11-17 for probe apparatus.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Yoshioka, Haruhiko.
Application Number | 20050253611 11/172922 |
Document ID | / |
Family ID | 31884628 |
Filed Date | 2005-11-17 |
United States Patent
Application |
20050253611 |
Kind Code |
A1 |
Yoshioka, Haruhiko |
November 17, 2005 |
Probe apparatus
Abstract
A probe apparatus includes a mounting member on which an object
to be inspected is mounted and a temperature thereof is being
adjusted, a probe card arranged opposite to the mounting member, a
driving mechanism which changes a relative positional relationship
between the mounting member and the probe card, and a sensor which
detects the distance between the sensor and the probe card. By way
of detecting the height of the deformed probe card through the use
of the sensor and revising the elevation distance of the mounting
member, the electrode pads of the wafer W and the probe pins can
electrically contact each other with a stable pin pressure,
providing high inspection reliability and an increase in
throughput.
Inventors: |
Yoshioka, Haruhiko;
(Nirasaki-shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
TOKYO ELECTRON LIMITED
Tokyo
JP
|
Family ID: |
31884628 |
Appl. No.: |
11/172922 |
Filed: |
July 5, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11172922 |
Jul 5, 2005 |
|
|
|
10642751 |
Aug 19, 2003 |
|
|
|
6927587 |
|
|
|
|
Current U.S.
Class: |
324/750.23 ;
324/754.11; 324/756.03 |
Current CPC
Class: |
G01R 31/2806 20130101;
G01R 31/2891 20130101; G01R 31/2887 20130101 |
Class at
Publication: |
324/754 |
International
Class: |
G01R 031/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 23, 2002 |
JP |
2002-243785 |
Claims
1-12. (canceled)
13. A probing method for use with a probe apparatus, wherein the
probe apparatus includes a mounting member for mounting thereon an
object to be inspected, a probe card provided with a plurality of
probe pins and a driving mechanism which changes a relative
positional relationship between the mounting member and the probe
card, the probing method comprising the step of: detecting a
displacement of a region of the probe card where the probe pins are
located with respect to the position of a part of the apparatus to
which the probe card is fixed.
14. The probing method of claim 13, wherein the detecting step
includes the step of sensing the displacement from a measuring
point at a back surface of the probe card, the back surface located
opposite a main surface of the probe card where the probe pins are
provided.
15. The probing method of claim 14, wherein the measuring point
corresponds to a center of the probe pins.
16. The probing method of claim 14, wherein the sensing step
includes the steps of: transmitting a laser beam toward the
measuring point; and receiving a laser beam reflected from the
measuring point, wherein the transmitting and receiving steps are
carried out at two separate locations corresponding to two opposite
sides of the probe card.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a probe apparatus; and,
more particularly, to a probe apparatus capable of providing an
enhanced inspection reliability.
BACKGROUND OF THE INVENTION
[0002] FIGS. 5A and 5B illustrate a conventional probe apparatus
used for inspecting electrical characteristics of, e.g., devices
formed on a wafer during the manufacture of the devices. As shown
in FIGS. 5A and 5B, the probe apparatus includes a loader chamber 1
for loading a wafer W and a prober chamber 2 for inspecting
electrical characteristics of the wafer W conveyed from the loader
chamber 1. The loader chamber 1 includes a cassette table 3, a
wafer convey mechanism 4 for conveying the wafer W to the prober
chamber 2, and a sub-chuck 5 for pre-aligning the wafer W with
reference to an orientation flat or a notch thereof during the
process of conveying the wafer W via the wafer convey mechanism
4.
[0003] Further, the prober chamber 2 includes a
temperature-controllable main chuck 6 on which the pre-aligned
wafer W provided by the wafer convey mechanism 4 is mounted; an XY
table 7 which moves the main chuck 6 in X and Y directions; a probe
card 8 arranged above the main chuck 6; and a position alignment
mechanism 9 which enables a plurality of probe pins 8a of the probe
card 8 to be precisely aligned to a plurality of electrode pads
(not shown) of the wafer W mounted on the main chuck 6. The
alignment mechanism 9 includes an upper camera 9b attached to an
alignment bridge 9a to monitor the wafer W and a lower camera 9c
attached to the main chuck 6 to monitor the probe pins 8a. The
alignment bridge 9a aligns the electrode pads of the wafer W and
the probe pins 8a by way of advancing from one end of the prober
chamber 2 to a probe center along a pair of guide rails 9d.
[0004] Furthermore, as shown in FIG. 5A, a test head T of a tester
is movably disposed on a head plate 2a of the prober chamber 2 and
is electrically connected with the probe card 8 via a performance
board (not shown). With the temperature of the wafer W on the main
chuck 6 being set at a temperature ranging from -20.degree. C. to
+150.degree. C., inspection signals are sent from the tester via
the test head T and the performance board to the probe pins 8a. The
electrical characteristics of a multiplicity of semiconductor
elements (devices) formed on the wafer W are inspected by applying
the inspection signals from the probe pins 8a to the electrode pads
of the wafer W.
[0005] The inspection of the wafer includes a high temperature
inspection and a low temperature inspection. During the high
temperature inspection process, the wafer is inspected after being
heated up to a predetermined temperature (e.g., at 100.degree. C.
or higher) by a temperature control mechanism embedded in the main
chuck 6. The low temperature inspection process is carried out
after cooling the wafer down to a predetermined temperature (e.g.,
at 0.degree. C. or lower) by the temperature control mechanism.
[0006] In the high temperature inspection process, however, since
the wafer is inspected at a high temperature at 100.degree. C. or
higher, the probe card 8 is heated by the main chuck 6 and
therefore, may be bent by thermal deformation. As a result, the Z
directional distance (Z vertical distance) between the probe pins
8a and the electrode pads of the wafer W can be varied by, e.g.,
100 .mu.m, causing poor contacts between the probe pins 8a and the
electrode pads of the wafer W and decreasing inspection
reliability. Therefore, the main chuck 6 is heated before the
inspection and the probe card 8 is preheated by placing the main
chuck 6 in proximity to the probe card 8. The wafer is then put
into a pseudo-contact state by considering the thermal deformation
of the probe card 8 and the actual inspection is performed so that
the poor contact problems between the probe pins 8a and the
electrode pads can be ameliorated.
[0007] However, even in such a case where the probe card 8 is
preheated and the wafer W is put into the pseudo-contact state
prior to the actual inspection stage, the Z directional
displacement of the probe card 8 due to a thermal deformation
caused by additional heating during the actual inspection stage and
that due to a contact load urged thereto during the inspection
stage cannot be properly estimated. Accordingly, an excess or
deficiency may occur in the contact load between the probe pins 8a
and the electrode pads of the wafer W, to thereby lower the
inspection reliability. Furthermore, a considerable amount of time
(e.g., 1.about.2 hours) may be required for the probe card 8 to
become thermally stable, leading to a significant decrease in
throughput.
SUMMARY OF THE INVENTION
[0008] It is, therefore, an object of the present invention to
provide a probe apparatus capable of performing the inspection with
improved reliability and increased throughput by way of detecting
the Z directional displacement of the probe card during the
inspection stage and stabilizing the contact load between the probe
pins and the objects to be inspected.
[0009] In accordance with the present invention, there is provided
a probe apparatus including a mounting member on which an object to
be inspected is mounted, a temperature of the object being adjusted
by the mounting member; a probe card arranged opposite to the
mounting member; a driving mechanism which changes a relative
positional relationship between the mounting member and the probe
card; and a sensor which detects the distance between the sensor
and the probe card.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The above and other objects and features of the present
invention will become apparent from the following description of
preferred embodiments given in conjunction with the accompanying
drawings, in which:
[0011] FIG. 1 is a schematic cross sectional view of a main portion
of a probe apparatus in accordance with a first preferred
embodiment of the present invention;
[0012] FIG. 2 shows graphs showing heights of a probe card detected
by a laser displacement sensor illustrated in FIG. 1;
[0013] FIG. 3 schematically illustrates a cross sectional view of a
main portion of a probe apparatus in accordance with a second
preferred embodiment of the present invention;
[0014] FIG. 4 depicts a schematic cross sectional view of a main
portion of a probe apparatus in accordance with a third preferred
embodiment of the present invention;
[0015] FIG. 5A offers a front cross sectional view of a prober
chamber of a conventional probe apparatus; and
[0016] FIG. 5B presents a plane view showing the interior of the
conventional probe apparatus shown in FIG. 5A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] Preferred embodiments of the present invention will now be
described in detail with reference to FIGS. 1 to 4, in which like
parts are denoted by like reference numerals.
[0018] As shown in FIG. 1, a probe apparatus 10 of a first
preferred embodiment includes, as in the conventional one shown in
FIGS. 5A and 5B, a main chuck 12 which is situated inside a prober
chamber 11 and is vertically moved in a Z direction by an elevating
mechanism (not shown) embedded therein; an XY table 13 which moves
the main chuck 12 in X and Y directions; a probe card 14 which is
arranged above the main chuck 12; an alignment mechanism (not
shown) which aligns the probe card 14 with a wafer W mounted on the
main chuck 12; and a controller 15 which controls driving
mechanisms thereof. The probe card 14 is fixed at an opening 11b of
a head plate 11a of the prober chamber 11.
[0019] When the wafer W is inspected, the alignment mechanism and
the XY table 13 cooperate to align the wafer W mounted on the main
chuck 12 to the probe pins 14a of the probe card 14. Afterwards,
the wafer W is moved by the XY table 13 and elevated in the Z
direction by the main chuck 12. When the electrode pads of the
wafer W electrically contact the probe pins 14a, the inspection of
electrical characteristics of the wafer W is carried out.
[0020] On the XY table 13 is installed a laser displacement sensor
16, which emits a laser beam to the probe card 14 to detect the
height thereof (i.e., the distance between the laser displacement
sensor 16 and the probe card 14). The laser displacement sensor 16
detects the height of the probe card 14 each time the XY table 13
moves, consequently detecting heights throughout the whole surface
of the probe card 14. The laser displacement sensor 16 is connected
to the controller 15 and operated under its control. The detected
heights are stored in the controller 15.
[0021] In accordance with the present invention, e.g., at room
temperature where the probe card 14 is not thermally deformed, the
main chuck 12 is moved by the XY table 13 within the inspection
range of wafer W, and the height of the probe card 14 is detected
as Z coordinate by the laser displacement sensor 16 every time a
movement is made. Then the Z coordinate data, and their
corresponding X, y coordinate data of the laser displacement sensor
16 are stored in the controller 15 as reference heights. A dashed
dotted line "B" in FIG. 2 shows a graph of reference heights
representing the relationship between the XY coordinates and the Z
coordinate at room temperature. Referring to the reference height,
the controller 15 obtains the height displacement of the probe card
14 caused by thermal deformation during the high temperature
inspection stage.
[0022] When the wafer W is inspected at a high temperature of,
e.g., 100.degree. C., the wafer W mounted on the main chuck 12 is
heated to 100.degree. C. and moved by the XY table 13, during which
the height of the probe card 14 is detected by the laser
displacement sensor 16 every time a movement is made. The detected
height is compared with the reference height at the same XY
coordinates. If the two heights are identical, the probe card 14 is
considered not to have been thermally deformed.
[0023] Since, however, the probe card 14 is deformed by thermal
expansion during the high temperature inspection process, the
detected height will not be identical with the reference height.
The controller 15 obtains the ratio of the detected height to the
reference height and, based thereon, revises the elevation distance
of the main chuck 12 in order to stabilize the electrical contacts
between the electrode pads of the wafer W and the probe pins 14a
with a constant pin pressure. Accordingly, the inspection of
electrical characteristics can be performed with high
reliability.
[0024] The operation of the probe apparatus 10 will now be
described in detail. While the main chuck 12 is heated under the
control of the controller 15, the wafer W is conveyed from a loader
chamber to the main chuck 12 in the prober chamber 11 via a convey
mechanism (not shown). And then, under the control of the
controller 15, the alignment mechanism and the XY table 13
cooperate to align the electrode pads of the wafer W mounted on the
main chuck 12 to the probe pins 14a of the probe card 14.
[0025] Subsequently, the main chuck 12 arrives at an initial
position of inspection and the laser displacement sensor 16 detects
the height of the heated probe card 14 thereat. At this time, the
probe card 14 is not required to be thermally stable. When the
height of the heated probe card 14 detected at the position of the
laser displacement sensor 16 is denoted by "b" and the height of
the probe card 14 at room temperature detected at the same position
is denoted by "a", the location, e.g., the center, of the probe
card 14 at which the probe pins 14a reside is assumed to be
deformed by the ratio "b/a". Accordingly, when the reference height
at the center of the probe card 14 at room temperature is "H", the
height of the deformed center of the probe card 14 is estimated to
be "H.times.(b/a)". When the main chuck 12 is elevated by a revised
height obtained based on the above estimated height and then
overdriven, the electrode pads of the wafer W and the probe pins
14a electrically contact each other with a predetermined pin
pressure to perform the inspection of electrical characteristics of
a device.
[0026] After the inspection, the main chuck 12 is lowered and the
wafer W is moved to a next device position by the XY table 13.
Then, in the same way described above, the elevation distance of
the main chuck 12 is revised based on the height detected by the
laser displacement sensor 16, making it possible to inspect the
electrical characteristics of the wafer W repeatedly with a stable
pin pressure. Therefore, even in the case where an organic
insulating film exists below the electrode pads, the inspection can
be performed with high reliability without damaging the insulating
film. The height of the probe card 14 during the inspection can be
stored sequentially in the controller 15, and the height variation
is shown in FIG. 2 by a solid line "A".
[0027] Alternately, instead of indirectly estimating a displacement
of the probe pins 14a based on the reference height "a" and the
measured height "b" that are obtained at a position of the probe
card 14 directly above the laser displacement sensor 16, the
displacement of the region of the probe card 14 at which the probe
pins 14a are disposed (which shall be called the "probe region"
hereinafter) can be directly measured by moving the laser
displacement sensor 16 directly underneath the probe region and
measuring the height "h" thereat just prior to adjusting the
elevation distance of the main chuck 12 for each inspection of
electrical characteristics of a device. In this case, such
reference height data as shown in FIG. 2 is not required since the
displacement measurement is carried out only at one center point of
the probe card 14 where the probe pins 14a are located and the
actual inspection is carried out.
[0028] As described above, the first preferred embodiment employs
the laser displacement sensor 16 installed on the XY table 13 to
detect the height of the probe card 14 thereby. Accordingly, even
if the probe card 14 thermally expands and deforms on account of
heat emission from the main chuck 12 during the high temperature
inspection of the wafer W as shown by the dashed dotted line in
FIG. 1, by way of detecting the height of the deformed probe card
14 through the use of the laser displacement sensor 16 and revising
the elevation distance of the main chuck 12, the electrode pads of
the wafer W and the probe pins 14a can electrically contact each
other with a stable pin pressure, providing high inspection
reliability. Moreover, the inspection is not required to be
postponed until the probe card 14 is thermally stabilized, which
leads to an increase in throughput.
[0029] FIG. 3 shows a probe apparatus 20 in accordance with a
second preferred embodiment of the present invention. In FIG. 3, a
controller is omitted. The probe apparatus 20 is identical to that
of the first preferred embodiment, excepting that the laser
displacement sensor 16 is attached to the main chuck 12. Therefore,
even if the main chuck 12 is pushed down and/or slanted by the
contact pressure applied to the main chuck 12 while inspecting a
device disposed at a peripheral region of the wafer W, such
displacement of the main chuck 12, along with the thermal
deformation of the probe card 14, can be detected as an overall
displacement of the probe card 14 by the laser displacement sensor
16. And since the elevation distance is corrected or adjusted based
on the displacement thus detected, the pin pressure between the
electrode pads of the wafer W and the probe pins 14a can be more
stable, leading to high inspection reliability.
[0030] FIG. 4 shows a probe apparatus 30 in accordance with a third
preferred embodiment of the present invention. In FIG. 4, a
controller is omitted for the sake of simplicity. The probe
apparatus 30 is identical to the first and the second preferred
embodiments, excepting that the laser displacement sensor 16(16a,
16b) is attached to the head plate 11a. Since the third preferred
embodiment has the laser displacement sensor 16 attached to the
head plate 11a, the Z directional displacement of the probe card 14
can be detected from the upper side thereof and the pin pressure
between the electrode pads of the wafer W and the probe pins 14a
can be stabilized, rendering high inspection reliability.
[0031] In this preferred embodiment, the laser displacement sensor
16 is comprised of two separate members 16a and 16b because the
laser beam is illuminated at an oblique angle to the upper surface
of the probe card 14. As will be readily appreciated by those
skilled in the art, one of those sensors 16a, 16b would be a laser
beam generating device and the other one would be a photo sensor
receiving a laser beam reflected by the upper surface of the probe
card 14. In the previous embodiments, the two members are
incorporated into a single body of the laser displacement sensor 16
since the laser beam is emitted onto the lower surface of the probe
card 14 at a substantially perpendicular angle. Also, in the third
embodiment, the actual real-time vertical displacement of the probe
card 14 can be directly measured by detecting the Z directional
displacement of the backside of the region where the probe pins 14a
are located. Therefore, the inspection of the devices can be
carried out with even more enhanced reliability. Further, in this
embodiment, such reference height data for the whole XY range as
shown in FIG. 2 is not required since the displacement measurement
is carried out only at one center point of the probe card 14 where
the probe pins 14a are located and the actual inspection is carried
out.
[0032] In the above-described preferred embodiments, the
description is made for the case in which the probe card 14 is
arranged above the main chuck 12. However, their positional
relationship can be arranged alternatively. That is, the main chuck
12 can be placed above the probe card 14. And also, the main chuck
12 and the probe card 14 can be disposed in a side by side
arrangement.
[0033] Further, in the above preferred embodiments, the relative
positional relationship between the main chuck 12 and the probe
card 14 is changed by moving the main chuck 12 in the X, Y and Z
directions through the use of the XY table 13 and the elevating
mechanism embedded therein. The relationship, however, may be
changed by moving the probe card 14 in the X, Y and Z directions
with the main chuck 12 being fixed. Alternately, for instance, the
main chuck 12 can be made to move in the X and Y directions while
the probe card 14 moves in the Z direction, or vice versa.
[0034] Still further, it is to be appreciated that other types of
displacement sensors, e.g., a capacitive sensor, can be used in
lieu of the laser displacement sensor.
[0035] While the invention has been shown and described with
respect to the preferred embodiments, it will be understood by
those skilled in the art that various changes and modifications may
be made without departing from the spirit and scope of the
invention as defined in the following claims.
* * * * *