U.S. patent application number 12/042286 was filed with the patent office on 2008-06-26 for method for probing impact sensitve and thin layered substrate.
Invention is credited to Sun Ya Lei, Uday Nayak, Lynn Howard Whitney.
Application Number | 20080150559 12/042286 |
Document ID | / |
Family ID | 39310170 |
Filed Date | 2008-06-26 |
United States Patent
Application |
20080150559 |
Kind Code |
A1 |
Nayak; Uday ; et
al. |
June 26, 2008 |
METHOD FOR PROBING IMPACT SENSITVE AND THIN LAYERED SUBSTRATE
Abstract
A method of moving a substrate to a probe card. The method
comprises moving a probe card and a substrate vertically closer to
one another employing dynamically changing velocities during the
moving. More than two different velocities are used during the
moving. The velocities are at zero only at an initial location and
a final location. The moving is such that the probe card and the
substrate contact each other with a soft impact. The velocities for
the moving begin with a high velocity and reduce to a lower
velocity so that the contact between the probe card and the
substrate us a microtouch impact.
Inventors: |
Nayak; Uday; (San Jose,
CA) ; Lei; Sun Ya; (Singapore, SG) ; Whitney;
Lynn Howard; (Lakehead, CA) |
Correspondence
Address: |
BLAKELY SOKOLOFF TAYLOR & ZAFMAN
1279 OAKMEAD PARKWAY
SUNNYVALE
CA
94085-4040
US
|
Family ID: |
39310170 |
Appl. No.: |
12/042286 |
Filed: |
March 4, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11271416 |
Nov 9, 2005 |
7362116 |
|
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12042286 |
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Current U.S.
Class: |
324/750.19 ;
324/754.11 |
Current CPC
Class: |
G01R 31/2887
20130101 |
Class at
Publication: |
324/754 |
International
Class: |
G01R 31/02 20060101
G01R031/02 |
Claims
1. A method for testing an electrical device comprising: moving a
first structure and a substrate vertically closer to one another
employing dynamically changing velocities during said moving,
wherein more than two different velocities are used during said
moving, and wherein velocities are at zero only at an initial
location and a final location, wherein said moving is such that
said first structure and said substrate contact each other with a
soft impact.
2. The method of claim 1 wherein said velocities are varied
continuously such that motions for said moving are continuous until
the final location.
3. The method of claim 1 wherein parameters for varying said
velocities are updated at least every 60 microsecond.
4. A method comprising: placing a substrate on a substrate
supporter provided in a cleaning chamber, said substrate supporter
moveable in XYZ directions; providing a first structure coupled to
a chuck, said first structure having at least one component
configured to perform a procedure on said substrate, said first
structure being moveable in XYZ directions; moving said first
structure and said substrate supporter in the Z-direction toward
one another using dynamically changing velocities during said
moving, wherein a plurality of different velocities are used during
said moving, wherein velocities are at zero only at an initial
location and a final location, wherein said moving further includes
moving said first structure and said substrate in the Z-direction
toward one another at a fast velocity before said first structure
and said substrate contact each other and impact at a slow velocity
as said first structure and said substrate contact each other
producing a microtouch impact.
5. The method of claim 4 wherein moving said first structure and
said substrate toward one another further comprising: moving said
substrate supporter in the Z-direction toward said first structure
using the initial velocity of zero, a second velocity, a third
velocity, and the final velocity of zero without stopping until a
desired contact is achieved between said first structure and said
substrate.
6. The method of claim 5 wherein said second velocity is faster
than said third velocity.
7. The method of claim 6 further comprising: returning said
substrate supporter to an initial position.
8. The method of claim 4 wherein moving said first structure and
said substrate supporter toward one another further comprising:
moving said first structure toward said substrate supporter using
an initial velocity of zero, a second velocity, a third velocity,
and a final velocity of zero without stopping until a desired
contact between said first structure and said substrate is
achieved.
9. The method of claim 8 wherein said second velocity is greater
than said third velocity.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of co-pending U.S. patent
application Ser. No. 11/271,416, filed Nov. 9, 2005, entitled
"Method For Probing Impact Sensitive and Thin Layered Substrate"
which is hereby incorporated herein by reference in its
entirety.
FIELD
[0002] The present invention relates generally to semiconductor
processing and more particularly to a probe card system and a
method for probing impact sensitive and thin-layered
substrates.
BACKGROUND
[0003] Integrated circuits are often manufactured on a
semiconductor substrate, such as a silicon wafer. The silicon wafer
is typically a thin circular plate of silicon that is 150, 200 or
300 millimeters in diameter and approximately 25 mils thick. A
single wafer will have numerous devices which are integrated
circuits and are imprinted on the wafer comprising a lattice of
devices. Each device consists of numerous layers of circuitry and a
collection of bonding pads. The bonding pads are small sites,
typically 3 mils square, made usually with aluminum (or other
conductive material) that eventually serves as the device's
connections to the pin leads. Other than the bonding pads, the
remainder of the wafer is coated with a final layer of an
insulating material such as silicon nitride, called the passivation
layer, which in many respects behaves like glass. The aluminum
itself forms a thin non-conductive layer of aluminum oxide, which
must be eliminated or broken through before good electrical contact
can be made.
[0004] Since the packaging of a device is somewhat expensive, it is
desirable to test a device before packaging to avoid packaging bad
devices. This process of testing devices before packaging is
referred to as the sort process. This process involves connecting a
device called a probe card to a special tester. The probe card has
a collection of electrical contacts or pins (also referred to as
probe elements) that stands in for the normal pins and wire leads
of a packaged device. The wafer is then positioned so that the
contacts or pins on the probe card make contact with a given
device's bonding pads and the tester runs a battery of electrical
tests on the device. A special machine, called a wafer prober, is
used to position each device on the wafer with respect to the probe
card. High accuracy is required, because the bonding pads are small
and if a probe card pin makes contact outside the bonding pad area,
the result may be a break in the passivation layer, which generally
results in a damaged device. Also, the card pins need to be cleaned
to ensure accuracy of such contact.
[0005] A primary purpose of wafer probing is to accurately position
the collection of devices, or dice, on a wafer in such a manner so
that the device's bonding pads make good electrical contact with a
probe card's probe pins so that the device may be properly tested
before dicing and packaging. Inaccuracy positioning may cause
damages to either the probe pins or the bonding pads, and/or other
components of the probe card and the devices on the substrate.
[0006] Types of damages that may occur include gouging of the
bonding pads so as to expose the metal layer underneath and
cracking of the pads thereby damaging the active components below.
Other damages include damages to the probe pins such as bending and
breaking. To avoid damages such as damages to the bonding pads, the
motions of the probe system are controlled so as to achieve a
"softer" (e.g., slower and less forceful) contact between the probe
pins and the bonding pads. In one current method, the substrate is
moved up to a specific height of contact, stopped, and the motion
of moving the substrate is changed. The motion is slowed down so
that the substrate can be moved closer to the probe pins with a
reduced motion. In that way, the contact between the bonding pads
and the probe pins is softer or slower. Such change of motion
substantially impacts the probe system's throughput.
[0007] It is desirable to provide a probe card cleaning device and
method, which overcomes the above limitations and drawbacks of the
conventional testing devices.
SUMMARY
[0008] Embodiments of the present invention provide improved
methods for moving a probe card toward a substrate in a probe
system for a particular procedure.
[0009] In one aspect, the invention pertains to a method of moving
a substrate to a probe card. The method comprises moving a probe
card and a substrate vertically closer to one another employing
dynamically changing velocities during the moving. More than two
different velocities are used during the moving. The velocities are
at zero only at an initial location and a final location. The
moving is such that the probe card and the substrate contact each
other with a soft impact. The velocities for the moving begin with
a high velocity and reduce to a lower velocity so that the contact
between the probe card and the substrate use a microtouch
impact.
[0010] In another aspect, the invention pertains to a method which
comprises placing a substrate on a substrate supporter provided in
a probe system. The substrate supporter is moveable in XYZ
directions. Next, a probe card coupled to a probe chuck of the
probe system is provided. The probe card has at least one probe pin
configured to perform a procedure on the substrate. The probe card
is also moveable in XYZ directions. Next, the probe chuck and the
substrate supporter are moved in the Z-direction toward one another
using dynamically changing velocities. During the moving, a
plurality of different velocities are used and the velocities are
at zero only at an initial location and a final location of the
probe card and the substrate. The method further includes moving
the probe card and/or the substrate in the Z-direction a fast
velocity before the probe card and the substrate contact each other
and at a slow velocity as the probe card and the substrate contact
each other producing a microtouch impact.
[0011] In another aspect, the invention pertains to a method which
comprises obtaining a first characteristic associated with a
substrate loaded on a substrate supporter and a second
characteristic associated with a probe card loaded on a probe card
supporter. Next, determine a set of velocities and a sequence of
velocities for moving the substrate supporter and the probe card
supporter toward each other based on the first characteristic and
the second characteristic to cause a contact between the probe card
and the substrate. The velocities including one or more fast
velocities and one or more slower velocities with respect to the
fast velocities. The velocities provides for a fast moving of the
probe card and/or the substrate toward each other and a slow moving
of the probe card and/or the substrate into contact with a
microtouch impact between the probe card and said substrate. Next,
execute a series of motions to carry out the moving.
[0012] More details of the embodiments of the present invention are
followed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The invention will be understood more fully from the
detailed description given below and from the accompanying drawings
of various embodiments of the invention, which, however, should not
be taken to limit the invention to the specific embodiments, but
are for explanation and understanding only. In the drawings:
[0014] FIG. 1 illustrates an example wafer prober system;
[0015] FIG. 2 illustrates another exemplary embodiment of a probe
system;
[0016] FIGS. 3-4 illustrate exemplary embodiment of a scrub pad
that can be used with various embodiments of the present
invention;
[0017] FIGS. 5-6 illustrate a motion profile of moving a substrate
to contact a probe card; and
[0018] FIGS. 7A-7C illustrate exemplary motion profiles that can be
used to move a substrate and a probe card closer to contact one
another with a microtouch impact; and
[0019] FIG. 8 illustrates an exemplary method of moving a probe
card and a substrate closer to one another according to some
embodiments of the present invention.
DETAILED DESCRIPTION
[0020] In the following description, for purposes of explanation,
numerous specific details are set forth in order to provide a
thorough understanding of the invention. It will be apparent t one
skilled in the art, however, that the invention can be practiced
without these specific details. In other instances, structures and
devices are shown in block diagram form to avoid obscuring the
invention.
[0021] Prior to describing exemplary methods of the present
invention that pertain to moving a probe card and a substrate
closer to and contact each other with a microtouch impact a short
description of an exemplary probe system is provided. An exemplary
probe system that can benefit from embodiments of the present
invention is described below. The probe system below is only an
example of a probe system that can be used with the present
invention. It is to be understood that other systems can also be
used in conjunction with embodiments of the present invention and
likewise benefit from the invention. Although the discussion of the
exemplary embodiments focus mainly on a probe system, the
embodiments are similarly applicable for other system where two
surfaces (or components thereon) need to come into contact with
each other with a microtouch impact, an impact where the surfaces
or components contact each other smoothly and softly without an
excessive force that may cause damages.
[0022] FIG. 1 of the accompanying drawings illustrates a probe
apparatus 100, according to an embodiment of the present invention,
for an electrical testing of a substrate (e.g., a silicon wafer)
having a plurality of terminals. The apparatus 100 includes a frame
101, a probe card 130, a substrate holder 102, a scrub device 152,
and a translation device 110.
[0023] The frame 101 includes an opening 116 through which the
probe card 130 is introduced into the frame 101. The frame 101 also
can define a testing and cleaning chamber 103 for the apparatus
100. The chamber 103 can be set to a suitable condition (e.g.,
suitable temperature and pressure) for the testing and cleaning a
wafer.
[0024] The probe card 130 is mounted to a probe card support
structure 140, which is further mounted or extended from a probe
card chuck 142. The chuck 142 actuates, manipulates, positions, or
controls the position of the probe card 130. The chuck 142 can be
connected to an arm 143 that is coupled to or is part of a motor
that is used to move actuate, manipulate, position, or align the
probe card 130. The probe chuck 142 may be configured to provide
movements of the probe card 130 in any of the X, Y, Z, and theta
directions 199. In addition, the movements of the probe card 130
can also be controlled by a processing unit or a controller 120
provided with or coupled to the apparatus 100. The controller 120
is typically a computer or a machine having a processor (not shown)
that can execute a program (a set of instructions) that controls
all of the components of and steps associated with the apparatus
100. In one embodiment, a computer program product is stored in a
machine-readable medium (not shown) or a memory storage medium that
communicates with the controller 120 and is executed by the
processor. In this embodiment, the program controls movements of
the probe card supporter, the substrate supporter, a testing cycle,
cleaning cycle, and other steps associated with the apparatus 100.
User interactive devices such as keyboard, mouse, and display (not
shown) can also be coupled to the controller 120 to allow for
controlling of the apparatus 100.
[0025] The probe card 130 includes a plurality of probe elements,
pins, or bars 132 extending from the bottom surface of the probe
card 130. The elements 132 are contact electrodes which may include
metallic pins. The probe elements 132 are also secured to the probe
card 130. The probe card 130 is used for making electrical contact
with terminals (contact pads) 114 on a substrate 112. The probe
elements 132 are brought into contact with the terminals 114. An
electrical tester (not shown) is connected to the probe elements
132 and the probe card 130. Electrical signals can be transmitted
from the electrical tester thorough the probe elements and the
terminals to the electrical circuits, or signals can be sent from
the circuits through the terminals and probe elements to the
electrical tester. The probe card 130 may be any of the different
varieties of probe cards, including for example membrane probe
cards.
[0026] The substrate holder 102 is mounted or supported by a wafer
chuck 106 which is further coupled to a base 104. In one
embodiment, the base 104 is located on a horizontal surface of the
frame 103. The base 104 is configured to translate a force to the
wafer chuck 106 to allow it to move in a vertical and/or horizontal
direction. In one embodiment, wafer chuck 106 is moveably coupled
to the base 104 in a manner which allows the wafer chuck 106 to be
moved in the X, Y, Z, and theta directions 199. The base 104 can
include a motor or an actuation mechanism 103 (known in the art) to
move the wafer chuck 106 in the X, Y, Z, and theta directions.
[0027] The wafer chuck 106 also accepts the attachment of a
substrate 112 via the substrate support 102. The substrate 112 is a
semiconductor wafer having one or more electrical components (not
shown) built or formed thereon or therein. Contact pads (terminals)
114 are provided on the substrate 112 for a testing purpose, in one
embodiment.
[0028] The wafer chuck 106 and the base 104 can also be coupled to
the controller 120 similar to previously described for the probe
card support structure 140 and the probe card chuck 142. In
addition, the movement of the wafer chuck 106, the base 104, as
well as the substrate support 102 can also be controlled by the
controller 120 coupled to the apparatus 100.
[0029] For a testing cycle, the probe card 130 is brought into
contact with the substrate 112 such that the probe elements 132
make contact with the contact pads 114 on the substrate so that a
particular electrical testing can take place. For instance, the
elements 132 make contact with the pads 114 of the substrate 112
when the probe card 130 and the substrate 112 are properly aligned
and brought sufficiently close to each other by the apparatus 100,
for example, via the assistance of an operator and/or the
controller 120. The pads 114 may comprise any contact electrode
surface including, but not limited to a flat surface or a solder
bump or pins or posts. The probe card 130 and the substrate 112
contact one another with a "microtouch" impact, in that the probe
card 130 and the substrate 112 sufficiently contact each other to
allow for the connection between the elements 132 and the pads 114
without too much force or too much impact that may cause damages to
the probe elements 132, the pads 114, or other elements of the
substrate 112 and/or the probe card 130, In according to
embodiments of the present invention, the probe card 130 and the
substrate 112 are brought into contact with a microtouch impact by
using a set of velocities where only the initial velocity and the
final velocity are at zero and the velocities during the moving are
changing from fast to slow to prevent excessive impact. More
details on controlling the velocities are described in more details
below.
[0030] The alignment for the probe card 130 with respect to the
substrate 112 can also be accomplished using a vision subsystem
(not shown) incorporated into the apparatus 100 and positioned in
the chamber 103. The vision subsystem of the apparatus 100 of the
present embodiment may use two cameras, a wafer alignment camera
(not shown) and a sensor camera (not shown). The wafer alignment
camera, which may contain both coaxial and oblique illumination
sources, is configured to view a substrate 112 on the wafer chuck
102. The vision subsystem is also configured to view a probe card
130 attached to the probe chuck 140.
[0031] While the system shown in FIG. 1 probes the wafer
horizontally, it will be appreciated that the various aspects of
the present invention may be used with vertical prober system in
which the flat surface of the wafer is rotated 90-degree from the
position shown in FIG. 1. Also, although the apparatus 100 shown in
this figure illustrates only one probe card 130 and one substrate
112, it is to be understood that the apparatus 100 may very well
include more than one of such components.
[0032] After a certain testing cycles, the probe elements 132 may
need to be cleaned or otherwise treated. A scrub device 152 is
provided for such cleaning or treating purpose. The scrub device
152 may be included within the chamber 103 as shown in FIG. 1. In
one embodiment, the scrub device 152 is placed on scrub supporter
150 and can be moved in the X, Y, and Z direction 199. The scrub
device 152 includes a scrub substrate or pad 154 placed on top of
the scrub device 152. The scrub supporter 150 can be moved by the
base 104 similarly to how the wafer chuck 106 is moved. A motor
similar to the motor 103 may be included in the base 104 to move
the scrub supporter 150. The scrub device 152 is aligned with the
probe card 130 for cleaning. The scrub device 152 is moved
vertically upward in the D.sub.100 direction so that the scrub pad
154 is at a higher position than the substrate 112; for instance,
the scrub device 152 is raised a distance 156 so as to place the
scrub device 152 to be higher than the substrate 112. In one
embodiment, a motor (not shown) is coupled to the scrub device 152
to move the scrub device 152 in the vertical direction (Z
direction) so that the scrub pad 154 can be brought closer to the
probe elements 132. The motor can also be configured to be able to
rotate the scrub device 152 for a particular cleaning process.
Alternatively, the motor that is used to control the probe card 130
can also be configured to rotate the probe card 130 for similar
cleaning processes.
[0033] The scrub pad 154 can be made of various materials that can
clean a probe element 132 of a probe card 130. In cleaning the
probe element 132, the scrub pad 154 can scrub, clean, maintain,
reshape, sharpen, or even modify the probe element 132 depending on
a desired cleaning process. The scrub pad 154 may also have a
predetermined mechanical or chemical characteristic such as
abrasiveness, density, elasticity, tackiness, planarity, and
chemical properties (acetic or basic).
[0034] In one embodiment, the scrub pad 154 includes a chemical
layer or layers or a gel-like material for a particular cleaning
process. FIGS. 3-4 illustrate an exemplary scrub pad 300 that can
be used for the scrub pad 154. In the present embodiment, the scrub
pad 300 includes a frame 302 that surrounds a cleaning stack 304.
The cleaning stack 304 includes one or more chemical layers or
cells that may be acetic or basic which can oxidize, reduce, or
clean contaminants, or which can induce a chemical reaction and/or
a mechanical action that removes contaminants. FIG. 4 illustrates
an exemplary cleaning stack 304 in more detail. The stack 304
includes a substrate 306, a layer 310 disposed on the layer 309,
and a layer 312 disposed on the layer 310. Between each layer,
there may be a seal layer 314 and 316. Each of the layers 308, 310,
and 312 may be a chemical layer having a particular characteristic
for a particular cleaning. The stack 304 may include a combination
of layer that performs both chemical and mechanical cleaning for a
probe element. The scrub pad 300 can include materials such as
tungsten, ceramic, aluminum, stainless steel, gel pad, sand paper,
etc. More details of the apparatus 100 can be found in a co-pending
patent application entitled "Method and apparatus for cleaning a
probe card," which has a Ser. No. 11/195,926, which is hereby
incorporated by reference in its entirety.
[0035] FIG. 2 illustrates yet another exemplary probe apparatus 200
that can be used for or benefit from embodiments of the present
invention. The apparatus 200 is similar to the apparatus 100 except
that in the apparatus 200, the scrub device is attached to a
platform that supports the substrate and that the apparatus 200
utilizes a mechanism that is used to move the substrate in
alignment with the probe card for testing to move a scrub device in
alignment with the probe card for cleaning the probe elements.
[0036] The apparatus 200 includes a frame 220, a probe card 230, a
substrate holder or supporter 202, a scrub pad mounting
plate/platform 210, and a translation device 201. The frame 220
includes an opening 203 through which the probe card 230 is
introduced into the chamber 205 of the apparatus 200.
[0037] The probe card 230 is mounted to a probe card support
structure 240, which is further mounted or extended from a probe
card chuck 242. The chuck 242 actuates, manipulates, positions, or
controls the position of the probe card 230. The chuck 242 can be
connected to an arm that is coupled to or is part of a motor that
is used to move, actuate, manipulate, position, or align the probe
card 230. The probe chuck 242 may be configured to provide movement
of the probe card 230 in any of the X, Y, Z, and theta directions
299. In addition, the movement of the probe card 230 can also be
controlled by a processing unit or a controller 221 coupled to the
apparatus 200 (similar to the controller 120 for the apparatus
100).
[0038] The probe card 230 includes a plurality of probe elements,
pins, or bars 232 extending from the bottom surface of the probe
card 230. The probe elements 232 are brought into contact with
terminals 209 provided on a substrate 212 for a particular
testing.
[0039] The substrate holder 212 is controlled by the translational
device 201. In one embodiment, the substrate holder 212 is mounted
to a platform 202 which is further supported by a wafer chuck 206
which is further coupled to a base 204. In one embodiment, the base
204 is located on a horizontal surface of the frame 220. The base
204 is configured to translate a force to the wafer chuck 206 to
allow it to move in a vertical and/or horizontal direction. In one
embodiment, wafer chuck 206 is moveably coupled to the base 204 in
a manner which allows the wafer chuck 206 to be moved in the X, Y,
Z, and theta directions 299. The base 204 can include a motor or an
actuation mechanism 203 (known in the art) to move the wafer chuck
in the X, Y, Z, and theta directions. Moving of the wafer chuck 206
translates respective movement to the platform 202 and the
substrate holder 212.
[0040] The wafer chuck 206 also accepts the attachment of a
substrate 208 via the substrate support 212. The substrate 208 is a
semiconductor wafer having one or more electrical components (not
shown) built or formed thereon or therein. Contact pads 209 are
provided on the substrate 208 for a testing purpose, in one
embodiment.
[0041] The wafer chuck 206 and the base 204 can also be coupled to
the controller 221 similar to previously described for the probe
card support structure 240 and the probe card chuck 242. In
addition, the movement of the wafer chuck 206, the base 204, the
platform 202, as well as the substrate support 202 can also be
controlled by the controller 220 coupled to the apparatus 200.
[0042] The elements 232 make contact with the pads 209 of the
substrate 208 when the probe card 230 and the substrate 208 are
properly aligned by the apparatus 200, for example, via the
assistance of an operator and/or the controller 221. The alignment
can also be accomplished using a vision subsystem (not shown)
incorporated into the apparatus 200 and positioned in the chamber
220. The vision subsystem of the apparatus 200 of the present
embodiment may use two cameras: a wafer alignment camera (not
shown) and a sensor camera (not shown). The wafer alignment camera,
which may contain both coaxial and oblique illumination sources, is
configured to view a substrate 208 on the substrate supporter 212.
The vision subsystem is also configured to view a probe card 230
attached to the probe chuck 240.
[0043] The scrub pad mounting plate 210 is also controlled by the
translational device 201. The scrub pad mounting plate 210 is
mounted on the platform 202. In one embodiment, the scrub pad
mounting plate 210 is coupled to the wafer chuck 206 (via the
platform 202) so that the chuck 206 can move the scrub pad mounting
plate 210 in the same way that the wafer chuck 206 moves the
substrate supporter 212. In one embodiment, the scrub pad mounting
plate 210 is attached to and adjacent to the substrate supporter
212. Thus, the same action that is used to move the substrate
supporter 212 is used to move the scrub pad mounting plate 210. In
the present embodiment, only one actuation mechanism is used to
move both the substrate supporter 212 and the scrub pad mounting
plate 210.
[0044] The scrub pad mounting plate 210 includes one or more
coupling member or mounting member 214 for securing a scrub pad
216A to the scrub pad mounting plate 210. The mounting member 214
can have the form of a track where complimentary track on the scrub
pad 216A can mount to and be secured thereto.
[0045] The scrub pad 216A and the scrub pad mounting plate 210 are
dimensioned so that when the scrub pad 216A is mounted onto the
scrub pad mounting plate 210, the scrub pad 216A is higher than the
substrate 208 that is loaded on the substrate supporter 212. When
mounted, the scrub pad 216A has a distance D.sub.200 that is higher
than the substrate 208 that is mounted on the substrate supporter
212. The wafer chuck 206 moves both the scrub pad mounting plate
210 and the scrub pad 216A using the same mechanism but with the
scrub pad 216A being dimensioned to be sufficiently thick, when
loaded, the scrub pad 216A is higher than the substrate 208 by the
distance D.sub.200. Thus, the same mechanism is used to raise the
substrate supporter 212 and the scrub pad mounting plate 210 at the
same time but with the scrub pad 216A ends up being higher than the
substrate due to its thickness. The scrub pad 216A thus can be
brought closer to the probe card for cleaning the probe elements
without an additional actuation mechanism.
[0046] In one embodiment, the scrub pad mounting plate 210 is
configured to allow loading/unloading of a new scrub pad. In one
embodiment, the apparatus 200 includes a loading/unloading station
231 that holds one or more scrub pads 216A-216G. The station 231
can be a cassette system configured to store a plurality of scrub
pads. The station 231 can also be a docking station with
compartments or slots configured to hold a plurality of scrub pads.
The loading/unloading station 231 can also be configured to load a
scrub pad onto the scrub pad mounting plate 210. In one embodiment,
the loading/unloading station 231 removes one scrub pad from the
scrub pad mounting plate 210 and places another scrub pad onto the
scrub pad mounting plate 210 (e.g., replacing a used scrub pad with
a new scrub pad).
[0047] In one embodiment, the loading/unloading station 231 is
configured to store a set of scrub pad 216A-216G of multiple scrub
pad materials of same types of different types. A used scrub pad
can be replaced by an unused pad at the loading/unloading station.
The apparatus 200 can also load a different scrub pad depending on
a particular cleaning process without shutting down the apparatus
200 for the replacement. In one embodiment, the loading/unloading
station 231 is configured to store scrub pads of different sizes
thus, the apparatus 200 can also conveniently load different size
probe card and different size scrub pad accordingly without
shutting down the apparatus 200 to replace the scrub pad.
[0048] The loading/unloading station 231 may be configured to
identify the types of scrub pad being stored at the
loading/unloading station 231. This ability enables cleaning cycle
recipe or parameter changes depending on the identified
characteristics of the particular scrub pad.
[0049] In one embodiment, the loading/unloading station 231 is
mounted on a track 218 that allows for the station 231 to be moved
around. A motor (not shown) may be coupled to the apparatus 200 to
control the movement of the station 231. The controller 221 can
also be coupled to the motor, the station 231, or the track 218 to
execute the movement of the station 231. In one embodiment, the
station 231 is moved closed to the scrub pad mounting plate 210 for
the loading and unloading of a scrub pad. In other embodiments, the
base 204 moves the platform 202 and the scrub pad mounting plate
210 over to the station 231 for the loading and unloading of a
scrub pad.
[0050] In one embodiment, the apparatus 200 includes a robotic
assembly 234 with a handle 233. The robotic assembly 234 may be
coupled to the station 231 and configured to move together with the
station 231. Upon command, the robotic assembly 234 (via the handle
233) moves a scrub pad from the station 231 and loads it onto the
scrub pad mounting plate 210. Similarly, the robotic assembly 234
also removes a scrub pad form the scrub pad mounting plate 210,
places it into the station 231 and optionally, loads another scrub
pad onto the scrub pad mounting plate 210. In one embodiment, the
robotic assembly includes a motor (not shown) that allows it to
move closer to the scrub pad mounting plate 210 to load and unload
a scrub pad. Thus, both the scrub pad mounting plate 210 and the
loading/unloading station 231 need not be moving for loading and
unloading a scrub pad and only the robotic assembly 234 needs to
move for such loading and unloading. Each of the scrub pads
216A-216G can be similar to the scrub pad 300 previously described.
More details of the apparatus 200 can also be found in the
previously referenced and incorporated application Ser. No.
11/195,926.
[0051] It is to be appreciated that the apparatus 100 may also be
configured to include a similar loading/unloading station to the
station 230 although it is not shown in FIG. 1. Additionally,
although apparatuses 100 and 200 are described, it is to be
understood that embodiments of the present invention can be
similarly applied to other probe systems.
[0052] FIGS. 5-6 illustrate exemplary motion profiles used by
current methods to move a substrate closer to a probe card for a
particular procedure or testing. To avoid damages to the probe
card, probe pins, substrate, devices on the substrate, and/or other
elements of the probe card and substrate, motion parameters used to
move the substrate closer to the probe card are adjusted and
changed to achieve a softer contact. Current methods include moving
the substrate up to specific heights of contact but not physical
contact and change the motion parameter (slower velocity) and
continue moving further up toward the height with the reduced
motion parameter and move down in the reverse sequences. As
illustrated in FIGS. 5-6, over a course of time (T) for moving a
substrate 12 loaded on a substrate chuck 10 to a probe card 20
having probe pins 22, several velocities are employed. Initially,
the substrate 12 begins with an initial velocity of zero, V.sub.0
and at a height H.sub.0. The substrate 12 is moved to a height
H.sub.100 with a fast velocity or full speed V.sub.100, then is
stopped for a duration of T.sub.100. During the time T.sub.100, the
velocity is adjusted. The velocity is also dropped to zero,
V.sub.0, during the time T.sub.100. The motion for the substrate 12
is then changed to a new velocity parameter V.sub.200, which is
slower than the V.sub.100. The substrate 12 moves up to a second
height H.sub.200 from the first height H.sub.100 at the velocity
V.sub.200. The substrate 12 is then again stopped for a duration of
T.sub.200. During the time T.sub.200, the velocity is adjusted. The
velocity is dropped to zero, V.sub.0, during the time T.sub.200.
The motion for the substrate 12 is then changed to yet another new
velocity parameter V.sub.300, which is slower than the V.sub.100
and V.sub.200. The velocity V.sub.300 should be one that will allow
the substrate 12 to touch the probe card 20 with a soft touch to
prevent damages. The substrate 12 moves a third height H.sub.300
from the height H.sub.200 at the velocity V.sub.300 where the probe
pins 22 can contact certain necessary components on the substrate
12 for a particular procedure. The current methods suffer a
substantial impact on the motion time, which impacts the system's
throughput due to the stopping, adjusting, and resetting velocity
at one or more intermediate heights and moving to the final
height.
[0053] Embodiments of the present invention describe a method to
move a substrate and a probe card closer to each other with a
microtouch impact (soft, smooth, and controlled touch without
potentially causing bending or other kind of damages to components)
and with motions that are varied "on the fly" without the need to
move to a specific height, stop, and change velocity. Motions are
varied on the fly when the motions are changing form one velocity
to another velocity without a stop or without using a velocity of
zero. The velocities (or accelerations) of the moving components
are thus dynamically changing (changing continuously) and until the
final position (impact) is achieved, the velocity is not at zero.
The velocities or the motion parameters for moving a substrate and
a probe card closer to each other are configured using continuously
changing (dynamically changing) motions. For a particular substrate
and probe card, information such as thickness, materials, and
density characteristics are obtained and used to configure a
particular motion profile. The motion profile includes a sequence
of velocities that will be used to move such substrate and probe
card closer and into contact with each other. The motion profile
can be programmed into a controller provided to run the probe
system, which can then execute the motions profile to bring the
substrate and probe card into contact with each other. The methods
of moving the substrate and the probe card closer to each other
according to the embodiments of the present invention change the
rate of force or impact as the substrate contacts the probe card.
The motion profile has initial velocities being fast and full speed
and reduced on the fly to slower velocities and slower velocities
for impact. Such motion profile reduces the impact with which the
probe elements initially contact the substrate elements without
sacrificing throughput.
[0054] In one embodiment, the substrate is moved toward a
stationary probe card with a full (fast) speed and the velocity of
the moving substrate is changed or reduced so that the substrate
approaches the probe card slower to allow the microtouch impact.
The velocities are constantly monitored and changed according to
the position of the substrate relative to the probe card. It is to
be understood that in other embodiments, the substrate may be
stationary instead and the probe card moves toward the substrate
with similar constantly monitored and changing velocities.
[0055] In one embodiment, the positions of the probe card supporter
and the substrate supporter in a probe system are determined so
that the velocities can be continuously monitored and changed as
the probe card and the substrate are brought closer to one another.
The initial and desired final positions and positions during moving
are also monitored or determined. For instance, with respect to the
apparatus 100 or 200, the initial positions for the probe card (130
or 230) and the substrate (112 or 208) are determined so that when
the substrate is moved up to the probe card (or the probe card
moving down to the substrate) the sequence of velocities for the
moving can be configured, implemented, and the velocities are
monitored and varied continuously to provide the microtouch impact.
The velocities of the motions for moving the probe card or the
substrate (or the probe card) from an initial location to a final
location for a microtouch impact between the substrate and the
probe card are continuously monitored and changed until the desired
impact is achieved.
[0056] In one embodiment, a probe card and a substrate are moved
vertically closer to one another using continuous or dynamically
changing velocities from fast to slow to prevent excessive force on
impact. The velocities are changing as the probe card and/or the
substrate is moving so that the velocities are only at zero at an
initial location (probe card and substrate apart) and a final
location (probe card and substrate contact each other). The
velocities for the moving may be updated frequently, such as at
least every 40-60 microseconds. The duration of the updates depends
on the locations (initial and final) of the substrate and the probe
card.
[0057] FIGS. 7A-7C illustrate exemplary motion profiles that can be
implemented into a probe system to move a substrate and a probe
card into contact with one another with a microtouch impact. In
FIG. 7A, the velocity begin from V.sub.0 and increases to
V.sub.fast to begin moving either the substrate toward the probe
card, the probe card toward the substrate, or both the probe card
and substrate toward one another. Under V.sub.fast, the probe card
and substrate are not yet at the locations to contact each other.
To decrease the impact force, the velocity decreases from
V.sub.fast to V.sub.medium, and decreases further to V.sub.slow1
and V.sub.slow2 until V.sub.0, which is the point where a contact
occurs. Until the contact point, the velocity of the moving
component is not at zero. Although not show, a similar motion
profile can be used to bring the substrate and/or the probe card
back to their initial location. Additionally, it may be that only
one velocity is needed to bring the components back to their
initial location after the contact and a particular procedure or
testing. The actual values of the velocities may vary depending on
information of the probe system, the initial locations, the desired
final locations, and other characteristics of the probe card and
the substrate. Such information is taken into account when the
sequence of velocities is being configured for the moving. As
mentioned, the sequence of velocities can be programmed into the
probe system in order to execute the moving.
[0058] In FIG. 7B, the velocity begin from V.sub.0 and increases to
V.sub.300 to begin moving either the substrate toward the probe
card, the probe card toward the substrate, or both the probe card
and substrate toward one another. The velocity V.sub.300 is
typically a fast speed used to move the probe card and substrate
toward one another but not to allowed them contact each other. To
decrease the impact force, the velocity changes (decreases) from
V.sub.300 to V.sub.320, and adjusts further to V.sub.330 until
V.sub.0, which is the point where a contact occurs. Until the
contact point, the velocity of the moving component is not at zero.
As before, a similar motion profile can be used to bring the
substrate and/or the probe card back to their initial location.
Additionally, it may be that only one velocity is needed to bring
the components back to their initial location after the contact and
a particular procedure or testing. The actual values of the
velocities may vary depending on information of the probe system,
the initial locations, the desired final locations, and other
characteristics of the probe card and the substrate. Such
information is taken into account when the sequence of velocities
is being configured for the moving. As mentioned, the sequence of
velocities can be programmed into the probe system in order to
execute the moving.
[0059] In FIG. 7C, the velocity begin from V.sub.0, increases to
V.sub.400, increases further to V.sub.420, and changes to V.sub.440
to begin moving either the substrate toward the probe card, the
probe card toward the substrate, or both the probe card and
substrate toward one another. Under V.sub.400-V.sub.440, the probe
card and substrate are not yet at the locations to contact each
other. To decrease the impact force, the velocity decreases from
V.sub.440 to V.sub.460, and may decrease further until V.sub.0,
which is the point where a contact occurs. Until the contact point,
the velocity of the moving component is not at zero. As before, a
similar motion profile can be used to bring the substrate and/or
the probe card back to their initial location. Additionally, it may
be that only one velocity is needed to bring the components back to
their initial location after the contact and a particular procedure
or testing. The actual values of the velocities may vary depending
on information of the probe system, the initial locations, the
desired final locations, and other characteristics of the probe
card and the substrate. Such information is taken into account when
the sequence of velocities is being configured for the moving. As
mentioned, the sequence of velocities can be programmed into the
probe system in order to execute the moving.
[0060] FIG. 8 illustrates an exemplary method 700 of moving a probe
card and substrate closer to one another to create a microtouch
impact for a particular testing. At 702, a probe card's
characteristic(s) are determined. The probe card characteristics
include at least the probe card material, thickness, composition,
length of the probe pins that will penetrate a layer on a
substrate, thickness of the probe pins, and location of the probe
card in a probe system. The probe card characteristics constitute
one or more attributes that are considered in configuring a
sequence of velocities for moving the probe card and substrate into
contact. At 704, a substrate's characteristic(s) are determined.
The substrate characteristics include at least the substrate
material, thickness, composition, length and/or width of the
substrate's contact pads, thickness of the contact pads, thickness
and material of a layer that the probe pins can penetrate, material
and thickness of a layer that cannot be disturbed, and location of
the substrate in a probe system. The initial locations and desired
final locations of the probe card, the substrate, as well as the
supporters for the probe card and the substrate are also determined
so as to determine the sequence of velocities to move the probe
card and the substrate into contact.
[0061] An auto alignment system and/or a visualization system may
be provided in a probe system to facilitate the determination of
the location or position of the probe card and the substrate
relative to one another. For instance, the visualization or the
alignment system may be configured to locate a known position on
the substrate relative to a known position on a motor used to move
the substrate supporter in order to control the motions of the
substrate supporter thus, the position of the substrate. The probe
system is configured to align the probe card to the substrate in a
way to align the probe pins to the contact pads on the substrate.
The probe system is programmed to know the contact height of the
probe card relative to the substrate. The alignment can be
controlled by a controller provided for the probe card system as is
known in the art.
[0062] At 706 and 708, the necessary velocities and sequence of
velocities are determined (706) and programmed into the probe
system (708) so that the probe card and the substrate can be moved
toward each other to a final microtouch impact. The velocities used
to move the probe card and the substrate toward each other are
constantly monitored and changed on the fly. During the moving, the
velocity does not remain at zero. In one embodiment, a sequence of
velocities are predetermined based on the characteristics of the
probe card and the substrate. The velocities are selected so that
either the probe card is moved toward a static substrate or a
substrate is moved toward a static probe card with various
different velocities. In one embodiment, at the initial take off,
the probe card is moved (via the probe card supporter) toward the
static substrate (loaded on the substrate supporter) beginning with
a full speed/fast velocity, then the motion is modified depending
on how far the probe card is to the substrate. The velocity is then
reduced to a slower velocity but not reduced to a zero velocity so
that when the probe card comes into contact with the substrate, the
impact is soft and smooth to create a microtouch impact. Only when
the impact occurs is the velocity at zero. At 710, the instructions
are execute to carry out the motions for the probe system to move
the probe card and the substrate into contact. The velocity
sequence is then used to dictate the moving so that the contact is
a microtouch impact.
[0063] In one embodiment, a processing unit or a controller (e.g.,
controller 120 or 221, FIGS. 1-2) is configured to execute a set of
instructions that can carry out the moving with a pre-selected
sequence of velocities.
[0064] While the invention has been described in terms of several
embodiments, those of ordinary skill in the art will recognize that
the invention is not limited to the embodiments described. The
method and apparatus of the invention, but can be practiced with
modification and alteration within the spirit and scope of the
appended claims. The description is thus to be regarded as
illustrative instead of limiting.
[0065] Having disclosed exempla embodiments, modifications and
variations may be made to the disclosed embodiments while remaining
within the spirit and scope of the invention as defined by the
appended claims.
* * * * *