U.S. patent application number 11/299896 was filed with the patent office on 2007-06-14 for transferring die(s) from an intermediate surface to a substrate.
This patent application is currently assigned to Symbol Technologies, Inc.. Invention is credited to David Addison, Michael R. Arneson, William R. Bandy, David Eastin.
Application Number | 20070131016 11/299896 |
Document ID | / |
Family ID | 38137942 |
Filed Date | 2007-06-14 |
United States Patent
Application |
20070131016 |
Kind Code |
A1 |
Addison; David ; et
al. |
June 14, 2007 |
Transferring die(s) from an intermediate surface to a substrate
Abstract
Dies that are attached to a die plate can be transferred to a
substrate. An actuator can be used to cause a die to be released
from the die plate and to come into contact with the substrate. For
example, the die may cover a corresponding hole in the die plate.
The actuator can move a pin into the hole in the die plate, thereby
pushing the die from the die plate. The actuator may be actuated by
an electromagnetic stimulus. For instance, a solenoid having
windings around a tubular core may provide the electromagnetic
stimulus to the actuator. Current may be provided to the windings
of the solenoid to generate the electromagnetic stimulus that
actuates the actuator. The actuator may be provided in the tubular
core of the solenoid.
Inventors: |
Addison; David; (Baltimore,
MD) ; Bandy; William R.; (Gambrills, MD) ;
Eastin; David; (Upton, MA) ; Arneson; Michael R.;
(Finksburg, MD) |
Correspondence
Address: |
STERNE, KESSLER, GOLDSTEIN & FOX P.L.L.C.
1100 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
Symbol Technologies, Inc.
Holtsville
NY
|
Family ID: |
38137942 |
Appl. No.: |
11/299896 |
Filed: |
December 13, 2005 |
Current U.S.
Class: |
72/402 |
Current CPC
Class: |
H01L 2924/00014
20130101; H01L 24/75 20130101; H01L 2224/16225 20130101; H01L 24/95
20130101; H01L 24/81 20130101; H01L 2224/83192 20130101; H01L
2224/05568 20130101; H01L 2224/05573 20130101; H01L 2224/32225
20130101; H01L 2924/14 20130101; H01L 2224/73204 20130101; H01L
21/67144 20130101; H01L 2224/73204 20130101; H01L 2224/16225
20130101; H01L 2224/32225 20130101; H01L 2924/00 20130101; H01L
2924/14 20130101; H01L 2924/00 20130101; H01L 2924/00014 20130101;
H01L 2224/05599 20130101 |
Class at
Publication: |
072/402 |
International
Class: |
B21J 7/16 20060101
B21J007/16 |
Claims
1. A method of transferring a plurality of integrated circuit dies
from a die plate to a substrate, comprising: (a) receiving a die
plate that has a first surface having a die attached thereto,
wherein the die covers a hole through the die plate; (b)
positioning the first surface of the die plate and the substrate to
be adjacent to each other such that the die is closely adjacent to
a corresponding contact area on a first surface of the substrate;
and (c) applying a stimulus to an actuator to cause the die to be
released from the die plate to come into contact with the contact
area.
2. The method of claim 1, wherein step (c) includes: moving a pin
of the actuator through the hole in response to the stimulus,
wherein moving the pin causes the die to be released from the die
plate.
3. The method of claim 1, further comprising: (d) providing a
current to windings of a solenoid to generate the stimulus.
4. The method of claim 1, further comprising: (d) generating a
magnetic force in response to applying the stimulus, wherein the
magnetic force causes the die to be released from the die
plate.
5. The method of claim 1, further comprising: (d) maintaining
contact between the die plate and a pin plate that includes the
actuator using the stimulus.
6. The method of claim 1, wherein step (a) includes: receiving the
die plate having a plurality of dies attached to the first surface
of the die plate, the die plate having a plurality of holes
therethrough, wherein each die of the plurality of dies covers a
corresponding hole through the die plate.
7. The method of claim 6, further comprising: (d) repeating step
(c) for each die of the plurality of dies to cause each die to be
released from the die plate to come into contact with a
corresponding contact area on the substrate.
8. A method of transferring an integrated circuit die from a die
plate to a substrate, comprising: (a) aligning an actuator pin of
an actuator and a hole in a die plate with each other, wherein the
hole is covered by a die that is attached to a first surface of the
die plate; and (b) providing an electromagnetic stimulus to the
actuator to cause the actuator pin to move into the hole and to
detach the die from the first surface.
9. The method of claim 8, further comprising: (c) providing a
current to a solenoid having windings around a tubular core in
which the actuator pin is provided to generate the electromagnetic
stimulus.
10. The method of claim 8, wherein step (b) includes: generating a
magnetic force, thereby causing the die to be detached from the die
plate.
11. The method of claim 8, wherein the electromagnetic stimulus
maintains contact between the die plate and a pin plate that
includes the actuator.
12. The method of claim 8, wherein step (a) includes: receiving the
die plate having a plurality of dies attached to the first surface
of the die plate, the die plate having a plurality of holes
therethrough, wherein each die of the plurality of dies covers a
corresponding hole through the die plate.
13. The method of claim 12, further comprising: (c) repeating step
(b) for each die of the plurality of dies to cause each die to be
detached from the first surface.
14. A system for transferring integrated circuit dies, comprising:
an actuator that includes a solenoid having windings around a
tubular hollow core, and an actuator pin positioned in the tubular
hollow core; and a die plate having a first surface to which a die
is attached, wherein the die covers a corresponding hole through
the die plate; wherein the actuator is configured to move the pin
through the hole to detach the die from the first surface of the
die plate based on an electromagnetic stimulus generated by the
solenoid.
15. The system of claim 14, further comprising: a die plate holder
configured to mount the die plate; and a substrate supply
configured to present a substrate, wherein the die plate holder is
further configured to position the first surface of the die plate
adjacent to the substrate such that the die is closely adjacent to
a corresponding contact area on a first surface of the
substrate.
16. The system of claim 14, further comprising: a current source to
provide a current to the windings to cause the pin to be moved
toward the die.
17. The system of claim 14, further comprising a pin plate coupled
to the die plate by the electromagnetic stimulus provided by the
solenoid.
18. The system of claim 14, wherein the first surface of the die
plate has a plurality of dies attached thereto, the die plate
having a plurality of holes therethrough, and wherein each die of
the plurality of dies covers a corresponding hole through the die
plate.
19. The system of claim 14, wherein the actuator pin has a
head.
20. The system of claim 14, wherein the actuator pin has opposing
magnetic poles.
21. A system to transfer integrated circuit dies, comprising: means
for actuating a pin aligned with a hole in a die plate, wherein the
hole is covered by a die that is attached to a first surface of the
die plate; and means for providing an electromagnetic stimulus to
the means for actuating to cause the pin to move into the hole and
to detach the die from the first surface.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The following applications of common assignee are herein
incorporated by reference in their entireties:
[0002] "Method, System, and Apparatus for Transfer of Dies Using a
Pin Plate," Ser. No. 10/866,159, filed Jun. 14, 2004 (Atty. Dkt.
No. 1689.0560000);
[0003] "Method, System, and Apparatus for Transfer of Dies Using a
Die Plate," Ser. No. 10/866,253, filed Jun. 14, 2004 (Atty. Dkt.
No. 1689.0550000); and
[0004] "Transferring Die(s) From an Intermediate Surface to a
Substrate," Ser. No. 11/091,944, filed Mar. 29, 2005 (Atty. Dkt.
No. 2319.0080000).
BACKGROUND OF THE INVENTION
[0005] 1. Field of the Invention
[0006] The present invention relates generally to the assembly of
electronic devices. More particularly, the present invention
relates to the transfer of integrated circuit (IC) dies to surfaces
in high volumes.
[0007] 2. Related Art
[0008] Pick and place techniques are often used to assemble
electronic devices. Such techniques involve a manipulator, such as
a robot arm, to remove integrated circuit (IC) chips or dies from a
wafer and place them into a die carrier. The dies are subsequently
mounted onto a substrate with other electronic components, such as
antennas, capacitors, resistors, and inductors to form an
electronic device.
[0009] Pick and place techniques involve complex robotic components
and control systems that handle only one die at a time. This has a
drawback of limiting throughput volume. Furthermore, pick and place
techniques have limited placement accuracy, and have a minimum die
size requirement.
[0010] One type of electronic device that may be assembled using
pick and place techniques is an RFID "tag." An RFID tag may be
affixed to an item whose presence is to be detected and/or
monitored. The presence of an RFID tag, and therefore the presence
of the item to which the tag is affixed, may be checked and
monitored by devices known as "readers."
[0011] As market demand increases for products such as RFID tags,
and as die sizes shrink, high assembly throughput rates and low
production costs are crucial in creating commercially viable
products. Accordingly, what is needed is a method and apparatus for
high volume assembly of electronic devices, such as RFID tags, that
overcomes these limitations.
SUMMARY OF THE INVENTION
[0012] The present invention is directed to methods, systems, and
apparatuses for producing one or more electronic devices, such as
RFID tags, that each include one or more dies. The dies each have
one or more electrically conductive contact pads that provide for
electrical connections to related electronics on a substrate.
[0013] According to embodiments of the present invention,
electronic devices are formed at greater rates than conventionally
possible. In one aspect, large quantities of dies can be
transferred directly from a wafer to corresponding substrates of a
web of substrates. In another aspect, large quantities of dies can
be transferred from a support surface to corresponding substrates
of a web of substrates. In another aspect, large quantities of dies
can be transferred from a wafer or support surface to an
intermediate surface, such as a die plate. The die plate may have
cells formed in a surface thereof in which the dies reside.
Otherwise, the dies can reside on a surface of the die plate. The
dies of the die plate can then be transferred to corresponding
substrates of a web of substrates.
[0014] In embodiments of the present invention, an integrated
circuit die is transferred from a die plate to a substrate by
electromagnetically stimulating an actuator. The die plate has a
first surface having a die attached thereto. The die covers a
corresponding hole through the die plate. An electromagnetic
stimulus actuates the actuator, which releases the die from the die
plate. For example, the actuator may include a pin that extends
into the hole in the die plate and moves the die from the die plate
into contact with the substrate.
[0015] The first surface of the die plate and the substrate may be
positioned to be adjacent to each other such that the die is
closely adjacent to a corresponding contact area on a first surface
of the substrate.
[0016] A solenoid may be used to generate the electromagnetic
stimulus. According to an embodiment, the solenoid includes
windings around a tubular core, and the actuator is provided in the
tubular core. A current may be provided in a first direction
through the windings to generate an electromagnetic stimulus having
a first polarity. The electromagnetic stimulus having the first
polarity may cause the actuator to move toward the die. A current
may be provided in a second direction that is opposite the first
direction through the windings to generate an electromagnetic
stimulus having a second polarity. According to an embodiment, the
electromagnetic stimulus having the second polarity may cause the
actuator to move away from the die. In another embodiment, the
actuator may have a magnetic property at steady state that moves
the actuator away from the die. In yet another embodiment, a spring
may be attached to the actuator to move the actuator toward or away
from the die.
[0017] These and other advantages and features will become readily
apparent in view of the following detailed description of the
invention. Note that the Summary and Abstract sections may set
forth one or more, but not all exemplary embodiments of the present
invention as contemplated by the inventor(s), and thus, are not
intended to limit claims.
BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES
[0018] The accompanying drawings, which are incorporated herein and
form a part of the specification, illustrate the present invention
and, together with the description, further serve to explain the
principles of the invention and to enable a person skilled in the
pertinent art to make and use the invention.
[0019] FIG. 1 shows a block diagram of an exemplary RFID tag,
according to an embodiment of the present invention.
[0020] FIGS. 2A and 2B show plan and side views of an exemplary
die, respectively.
[0021] FIGS. 2C and 2D show portions of a substrate with a die
attached thereto, according to example embodiments of the present
invention.
[0022] FIG. 3 is a flowchart illustrating a device assembly
process, according to embodiments of the present invention.
[0023] FIGS. 4A and 4B are plan and side views of a wafer having
multiple dies affixed to a support surface, respectively.
[0024] FIG. 5 is a view of a wafer having separated dies affixed to
a support surface.
[0025] FIG. 6 shows a system diagram illustrating example options
for transfer of dies from wafers to substrates, according to
embodiments of the present invention.
[0026] FIG. 7 is a flowchart of a method for transferring dies from
an intermediate surface to a substrate using an electromagnetic
stimulus, according to embodiments of the present invention.
[0027] FIG. 8 is a cross-sectional view of a die plate, according
to an example embodiment of the present invention.
[0028] FIG. 9 is a plan view of the die plate shown in FIG. 8,
according to an example embodiment of the present invention.
[0029] FIG. 10 is a cross-sectional view of the die plate shown in
FIG. 8, in which dies are attached to a surface of the die plate,
according to an example embodiment of the present invention.
[0030] FIG. 11 shows a system, according to an example embodiment
of the present invention.
[0031] FIG. 12 shows the system of FIG. 11 in which an actuator
causes a die to be detached from a die plate, according to an
example embodiment of the present invention.
[0032] FIG. 13 shows the system of FIG. 11 having a plurality of
actuators, according to an example embodiment of the present
invention.
[0033] The present invention will now be described with reference
to the accompanying drawings. In the drawings, like reference
numbers generally indicate identical, functionally similar, and/or
structurally similar elements. The drawing in which an element
first appears is indicated by the leftmost digit(s) in the
reference number.
DETAILED DESCRIPTION OF THE INVENTION
1.0 Overview
[0034] The present invention provides improved processes and
systems for assembling electronic devices, including RFID tags. The
present invention provides improvements over previous processes.
Conventional techniques include vision-based systems that pick and
place dies one at a time onto substrates. The present invention can
transfer multiple dies simultaneously. Vision-based pick and place
systems are limited as far as the size of dies that may be handled,
such as being limited to dies larger than 600 square microns
(.mu.m.sup.2). The present invention is applicable to dies having
an area of 100 .mu.m.sup.2 and even smaller. Furthermore, yield is
poor in conventional systems, where two or more dies may be
accidentally picked up at a time, causing losses of additional
dies. The present invention allows for improved yield values.
[0035] The present invention provides an advantage of simplicity.
Conventional die transfer tape mechanisms may be used by the
present invention. Furthermore, much higher fabrication rates are
possible. Previous techniques processed 5-8 thousand units per
hour. The present invention provides improvements in these rates by
a factor of N. For example, embodiments of the present invention
can process dies 5 times as fast as conventional techniques, at 100
times as fast as conventional techniques, and at even faster rates.
Furthermore, because the present invention allows for flip-chip die
attachment techniques, wire bonds are not necessary. However, in
embodiments, the present invention is also applicable to wire
bonded die configurations.
[0036] Elements of the embodiments described herein may be combined
in any manner. Example RFID tags are described in section 1.1.
Assembly embodiments for devices are described in section 1.2. More
detailed assembly embodiments for devices are described in sections
2.0 and 3.0.
1.1 Example Electronic Device
[0037] The present invention is directed to techniques for
producing electronic devices, such as RFID tags. For illustrative
purposes, the description herein primarily relates to the
production of RFID tags. However, the invention is also adaptable
to the production of further electronic device types (e.g.,
electronic devices including one or more IC dies or other
electrical components mounted thereto), as would be understood by
persons skilled in the relevant art(s) from the teachings herein.
Furthermore, for purposes of illustration, the description herein
primarily describes attachment of dies to substrates. However,
embodiments of the present invention are also applicable to the
attachment of other types of electrical components to substrates,
including any type of surface mount component (e.g., surface mount
resistors, capacitors, inductors, diodes, etc.), as would be
understood by persons skilled in the relevant art(s).
[0038] FIG. 1 shows a block diagram of an exemplary RFID tag 100,
according to an embodiment of the present invention. As shown in
FIG. 1, RFID tag 100 includes a die 104 and related electronics 106
located on a tag substrate 116. Related electronics 106 includes an
antenna 114 in the present example. Die 104 can be mounted onto
antenna 114 of related electronics 106, or on other locations of
substrate 116. As is further described elsewhere herein, die 104
may be mounted in either a pads up or pads down orientation.
[0039] RFID tag 100 may be located in an area having a large
number, population, or pool of RFID tags present. Tag 100 receives
interrogation signals transmitted by one or more tag readers.
According to interrogation protocols, tag 100 responds to these
signals. The response(s) of tag 100 includes information that the
reader can use to identify the corresponding tag 100. Once the tag
100 is identified, the existence of tag 100 within a coverage area
defined by the tag reader is ascertained.
[0040] RFID tag 100 may be used in various applications, such as
inventory control, airport baggage monitoring, as well as security
and surveillance applications. Thus, tag 100 can be affixed to
items such as airline baggage, retail inventory, warehouse
inventory, automobiles, compact discs (CDs), digital video discs
(DVDs), video tapes, and other objects. Tag 100 enables location
monitoring and real time tracking of such items.
[0041] In the present embodiment, die 104 is an integrated circuit
that performs RFID operations, such as communicating with one or
more tag readers (not shown) according to various interrogation
protocols. Exemplary interrogation protocols are described in U.S.
Pat. No. 6,002,344 issued Dec. 14, 1999 to Bandy et al., titled
"System and Method for Electronic Inventory," and U.S. patent
application Ser. No. 10/072,885, filed on Feb. 12, 2002, both of
which are incorporated by reference herein in their entirety. RFID
dies of the present invention may communicate according to any RFID
communication protocol(s), including binary traversal, slotted
Aloha, Class 0, Class 1, Gen 2, and other protocols. Die 104
includes a plurality of contact pads that each provide an
electrical connection with related electronics 106.
[0042] Related electronics 106 are connected to die 104 through a
plurality of contact pads of IC die 104. In embodiments, related
electronics 106 provide one or more capabilities, including RF
reception and transmission capabilities, impedance matching, sensor
functionality, power reception and storage functionality, as well
as additional capabilities. Components of related electronics 106
can be mounted or formed on substrate 116 in any manner. For
example, components of related electronics 106 can be printed onto
a tag substrate 116 with materials, such as conductive inks.
Examples of conductive inks include silver conductors 5000, 5021,
and 5025, produced by DuPont Electronic Materials of Research
Triangle Park, N.C. Other example materials or means suitable for
printing related electronics 106 onto tag substrate 116 include
polymeric dielectric composition 5018 and carbon-based PTC resistor
paste 7282, which are also produced by DuPont Electronic Materials
of Research Triangle Park, N.C. Other materials or means that may
be used to deposit the component material onto the substrate would
be apparent to persons skilled in the relevant art(s) from the
teachings herein.
[0043] As shown in FIG. 1, tag substrate 116 has a first surface
that accommodates die 104, related electronics 106, as well as
further components of tag 100. Tag substrate 116 also has a second
surface that is opposite the first surface. An adhesive material
and/or backing can be included on the second surface. When present,
an adhesive backing enables tag 100 to be attached to objects, such
as books, containers, and consumer products. Tag substrate 116 is
made from a material, such as polyester, paper, plastic, fabrics
such as cloth, and/or other materials such as commercially
available Tyvec.RTM..
[0044] In some implementations of tags 100, tag substrate 116 can
include an indentation, "cavity," or "cell" (not shown in FIG. 1)
that accommodates die 104. An example of such an implementation is
included in a "pads up" orientation of die 104.
[0045] FIGS. 2A and 2B show plan and side views of an example die
104. Die 104 includes four contact pads 204a-d that provide
electrical connections between related electronics 106 (not shown)
and internal circuitry of die 104. Note that although four contact
pads 204a-d are shown, any number of contact pads may be used,
depending on a particular application. Contact pads 204 are
typically made of an electrically conductive material during
fabrication of the die. Contact pads 204 can be further built up if
required by the assembly process, by the deposition of additional
and/or other materials, such as gold or solder flux. Such post
processing, or "bumping," will be known to persons skilled in the
relevant art(s).
[0046] FIG. 2C shows a portion of a substrate 116 with die 104
attached thereto, according to an example embodiment of the present
invention. As shown in FIG. 2C, contact pads 204a-d of die 104 are
coupled to respective contact areas 210a-d of substrate 116.
Contact areas 210a-d provide electrical connections to related
electronics 106. The arrangement of contact pads 204a-d in a
rectangular (e.g., square) shape allows for flexibility in
attachment of die 104 to substrate 116, and good mechanical
adhesion. This arrangement allows for a range of tolerances for
imperfect placement of IC die 104 on substrate 116, while still
achieving acceptable electrical coupling between contact pads
204a-d and contact areas 210a-d. For example, FIG. 2D shows an
imperfect placement of IC die 104 on substrate 116. However, even
though IC die 104 has been improperly placed, acceptable electrical
coupling is achieved between contact pads 204a-d and contact areas
210a-d.
[0047] Contact pads 204 can be attached to contact areas 210 of
substrate 116 using any suitable conventional or other attachment
mechanism, including solder, an adhesive material (including
isotropic and anisotropic adhesives), mechanical pressure (e.g.,
being held in place by an encapsulating material), etc.
[0048] Note that although FIGS. 2A-2D show the layout of four
contact pads 204a-d collectively forming a rectangular shape, a
greater or lesser number of contact pads 204 may be used.
Furthermore, contact pads 204a-d may be laid out in other shapes in
other embodiments.
1.2 Device Assembly
[0049] The present invention is directed to continuous-roll
assembly techniques and other techniques for assembling electronic
devices, such as RFID tag 100. Such techniques involve a continuous
web (or roll) of the material of the substrate 116 that is capable
of being separated into a plurality of devices. Alternatively,
separate sheets of the material can be used as discrete substrate
webs that can be separated into a plurality of devices. As
described herein, the manufactured one or more devices can then be
post processed for individual use. For illustrative purposes, the
techniques described herein are made with reference to assembly of
tags, such as RFID tag 100. However, these techniques can be
applied to other tag implementations and other suitable devices, as
would be apparent to persons skilled in the relevant art(s) from
the teachings herein.
[0050] The present invention advantageously eliminates the
restriction of assembling electronic devices, such as RFID tags,
one at a time, allowing multiple electronic devices to be assembled
in parallel. The present invention provides a continuous-roll
technique that is scalable and provides much higher throughput
assembly rates than conventional pick and place techniques.
[0051] FIG. 3 shows a flowchart 300 with example steps relating to
continuous-roll production of RFID tags 100, according to example
embodiments of the present invention. FIG. 3 shows a flowchart
illustrating a process 300 for assembling tags 100. The process 300
depicted in FIG. 3 is described with continued reference to FIGS.
4A and 4B. However, process 300 is not limited to these
embodiments.
[0052] Process 300 begins with a step 302. In step 302, a wafer 400
(shown in FIG. 4A) having a plurality of dies 104 is produced. FIG.
4A illustrates a plan view of an exemplary wafer 400. As
illustrated in FIG. 4A, a plurality of dies 104a-n are arranged in
a plurality of rows 402a-n.
[0053] In a step 304, wafer 400 is optionally applied to a support
structure or surface 404. Support surface 404 includes an adhesive
material to provide adhesiveness. For example, support surface 404
may be an adhesive tape that holds wafer 400 in place for
subsequent processing. For instance, in example embodiments,
support surface 404 can be a "green tape" or "blue tape," as would
be understood by persons skilled in the relevant art(s). FIG. 4B
shows an example view of wafer 400 in contact with an example
support surface 404. In some embodiments, wafer 400 is not attached
to a support surface, and can be operated on directly.
[0054] In a step 306, the plurality of dies 104 on wafer 400 are
separated or "singulated". For example, step 306 may include
scribing wafer 400 using a wafer saw, laser etching, or other
singulation mechanism or process. FIG. 5 shows a view of wafer 400
having example separated dies 104 that are in contact with support
surface 404. FIG. 5 shows a plurality of scribe lines 502a-l that
indicate locations where dies 104 are separated.
[0055] In a step 308, the plurality of dies 104 is transferred to a
substrate. For example, dies 104 can be transferred from support
surface 404 to tag substrates 116. Alternatively, dies 104 can be
directly transferred from wafer 400 to substrates 116. In an
embodiment, step 308 may allow for "pads down" transfer.
Alternatively, step 308 may allow for "pads up" transfer. As used
herein the terms "pads up" and "pads down" denote alternative
implementations of tags 100. In particular, these terms designate
the orientation of connection pads 204 in relation to tag substrate
116. In a "pads up" orientation for tag 100, die 104 is transferred
to tag substrate 116 with pads 204a-204d facing away from tag
substrate 116. In a "pads down" orientation for tag 100, die 104 is
transferred to tag substrate 116 with pads 204a-204d facing
towards, and in contact with tag substrate 116.
[0056] Note that step 308 may include multiple die transfer
iterations. For example, in step 308, dies 104 may be directly
transferred from a wafer 400 to substrates 116. Alternatively, dies
104 may be transferred to an intermediate structure, and
subsequently transferred to substrates 116. Example embodiments of
such die transfer options are described below in reference to FIG.
6.
[0057] Note that steps 306 and 308 can be performed simultaneously
in some embodiments. This is indicated in FIG. 3 by step 320, which
includes both of steps 306 and 308.
[0058] Example embodiments of the steps of flowchart 300, are
described in co-pending applications, U.S. Ser. No. 10/866,148,
titled "Method and Apparatus for Expanding a Semiconductor Wafer";
U.S. Ser. No. 10/866,150, titled "Method, System, and Apparatus for
Transfer of Dies Using a Die Plate Having Die Cavities"; U.S. Ser.
No. 10/866,253, titled "Method, System, and Apparatus for Transfer
of Dies Using a Die Plate"; U.S. Ser. No. 10/866,159, titled
"Method, System, and Apparatus for Transfer of Dies Using a Pin
Plate"; and U.S. Ser. No. 10/866,149, titled "Method, System, and
Apparatus for High Volume Transfer of Dies," each of which is
herein incorporated by reference in its entirety.
[0059] In a step 310, post processing is performed. For example,
during step 310, assembly of RFID tag(s) 100 is completed. Example
post processing of tags that can occur during step 310 are provided
as follows:
[0060] (a) Separating or singulating tag substrates 116 from the
web or sheet of substrates into individual tags or "tag inlays." A
"tag inlay" or "inlay" is used generally to refer to an assembled
RFID device that generally includes a integrated circuit chip and
antenna formed on a substrate.
[0061] (b) Forming tag "labels." A "label" is used generally to
refer to an inlay that has been attached to a pressure sensitive
adhesive (PSA) construction, or laminated and then cut and stacked
for application through in-mould, wet glue or heat seal application
processes, for example. A variety of label types are contemplated
by the present invention. In an embodiment, a label includes an
inlay attached to a release liner by pressure sensitive adhesive.
The release liner may be coated with a low-to-non-stick material,
such as silicone, so that it adheres to the pressure sensitive
adhesive, but may be easily removed (e.g., by peeling away). After
removing the release liner, the label may be attached to a surface
of an object, or placed in the object, adhering to the object by
the pressure sensitive adhesive. In an embodiment, a label may
include a "face sheet", which is a layer of paper, a lamination,
and/or other material, attached to a surface of the inlay opposite
the surface to which the pressure sensitive material attaches. The
face sheet may have variable information printed thereon, including
product identification regarding the object to which the label is
attached, etc.
[0062] (c) Testing of the features and/or functionality of the
tags.
[0063] FIG. 6 further describes example flows for step 308 of FIG.
3. FIG. 6 shows a high-level system diagram 600 that provides a
representation of the different modes or paths of transfer of dies
from wafers to substrates. FIG. 6 shows a wafer 400, a substrate
web 608, and a transfer surface 610. Two paths are shown in FIG. 6
for transferring dies, a first path 602, which is a direct path,
and a second path 604, which is a path having intermediate
steps.
[0064] For example, as shown in FIG. 6, first path 602 leads
directly from wafer 400 to substrate web 608. In other words, dies
can be transferred from wafer 400 to substrates of substrate web
608 directly, without the dies having first to be transferred from
wafer 400 to another surface or storage structure. However, as
shown in path 604, at least two steps are required, path 604A and
path 604B. For path 604A, dies are first transferred from wafer 400
to an intermediate transfer surface 610. The dies then are
transferred from transfer surface 610 via path 604B to the
substrates of web 608. Paths 602 and 604 each have their
advantages. For example, path 602 can have fewer steps than path
604, but can have issues of die registration, and other
difficulties. Path 604 typically has a larger number of steps than
path 602, but transfer of dies from wafer 400 to a transfer surface
610 can make die transfer to the substrates of web 608 easier, as
die registration may be easier.
[0065] Any of the intermediate/transfer surfaces and final
substrate surfaces may or may not have cells formed therein for
dies to reside therein. Various processes described below may be
used to transfer multiple dies simultaneously between first and
second surfaces, according to embodiments of the present invention.
In any of the processes described herein, dies may be transferred
in either pads-up or pads-down orientations from one surface to
another.
[0066] Elements of the die transfer processes described herein may
be combined in any way, as would be understood by persons skilled
in the relevant art(s). Example die transfer processes, and related
example structures for performing these processes, are further
described in the following subsections.
2.0 Die Transfer Embodiments
[0067] FIG. 7 shows a flowchart 700 of a method of transferring
dies from an intermediate surface to a substrate using an
electromagnetic stimulus (e.g., an electromagnetic field),
according to embodiments of the present invention. The flowchart
depicted in FIG. 7 is described with continued reference to FIGS.
8-13. However, flowchart 700 is not limited to those embodiments.
Further operational and structural embodiments of the present
invention will be apparent to persons skilled in the relevant arts
based on the following discussion. Note that in alternative
embodiments, steps shown in FIG. 7 can occur in an order other than
that shown, and in some embodiments, not all steps shown are
necessary.
[0068] Flowchart 700 begins at step 702. In step 702, a die plate
is received having a die attached to a first surface thereof. For
example, the die plate is die plate 802 shown in FIG. 8. FIG. 8 is
a cross-sectional view of die plate 802, according to an example
embodiment of the present invention. As shown in FIG. 8, die plate
802 has a plurality of holes 804 extending from a first surface 806
to a second surface 808 of die plate 802. Example embodiments of
die plates are described in co-pending applications, U.S. Ser. No.
10/866,150, titled "Method, System, and Apparatus for Transfer of
Dies Using a Die Plate Having Die Cavities," (Atty. Dkt.
1689.0540000) and U.S. Ser. No. 10/866,253, titled "Method, System,
and Apparatus for Transfer of Dies Using a Die Plate," (Atty. Dkt.
1689.0550000), both of which are herein incorporated by reference
in their entireties.
[0069] Although not shown in FIG. 8, die plate 802 can be supported
by a die plate holder, which may include a clamp, or other
mechanism for holding die plate 802. According to an embodiment,
die plate 802 has a thickness, t, of 20 milli-inches (mils) or
less. In another embodiment, die plate 802 has a thickness, t, of
10 mils or less. Die plate 802 may be fabricated in less than one
hour and/or at a cost of less than $100.
[0070] FIG. 9 is a plan view of die plate 802, according to an
example embodiment of the present invention. In FIG. 9, die plate
802 includes eight rows and eight columns of holes 804 for
illustrative purposes. However, die plate 802 may have any number
of rows and/or columns.
[0071] FIG. 10 is a cross-sectional view of die plate 802, in which
dies 104a-d are attached to first surface 806 of die plate 802,
according to an example embodiment of the present invention. An
adhesive material may be used to adhere dies 104a-d to first
surface 806.
[0072] In step 704, the first surface of the die plate and the
substrate are positioned to be adjacent to each other. For example,
FIG. 11 shows a system 1100 according to an example embodiment of
the present invention. In FIG. 11, die plate 802 and substrate 1102
are positioned to be adjacent to each other such that contact pads
204a and 204b of die 104a are closely adjacent to corresponding
contact areas 210a-b of substrate 1102. Note that die plate 802 and
substrate 1102 in various embodiments can be positioned to varying
degrees of closeness to each other, including distances other than
that shown in FIG. 11.
[0073] In step 706, an electromagnetic stimulus is applied to an
actuator to cause the die to be released from the die plate to come
into contact with the contact area. FIG. 11 shows an example
actuator 1150 that includes a first actuator element 1110 and a
second actuator element 1130. In the embodiment of FIG. 11, first
actuator element 1110 is shown as a cylindrical actuator body
having a head 1122 and a pin 1112, and second actuator element 1130
is a solenoid coil surrounding the actuator body of first actuator
element 1110. Head 1122 of first actuator element 1110 may be
configured similarly to a head of a nail. In FIG. 11, system 1100
includes a pin plate 1104 having a hole 1120 into which first
actuator element 1110 may be provided. Hole 1120 extends from a
first surface 1116 of pin plate 1104 to a second surface 1118 of
pin plate 1104. The coil of second actuator element 1130 surrounds
hole 1120 in pin plate 1104.
[0074] In FIG. 11, first actuator element 1110 is shown to be
magnetic. The magnetic poles of first actuator element 1110 are
indicated by the symbols "N" and "S". In the embodiment of FIG. 11,
a magnetic property of first actuator element 1110 causes first
actuator element 1110 and a plate 1114 to be in contact with each
other in a steady state condition. Plate 1114 is present to limit
the distance by which first actuator element 1110 can move from die
plate 802. When present, plate 1114 may also provide environmental
protection for actuator 1150. However, system 1100 need not
necessarily include plate 1114.
[0075] As shown in FIG. 11, plate 1114 and first actuator element
1110 are magnetically coupled in the absence of an electromagnetic
stimulus, for example. Opposing poles "N" and "S" of first actuator
element 1110 generate a magnetic field that may react with a
magnetic polarization of plate 1114 if plate 1114 is made from a
magnetic metal. If plate 1114 has a polarization of "S", then the
"N" pole of first actuator element 1110 may be attracted toward
plate 1114. For instance, the magnetic field generated by the
opposing poles "N" and "S" of first actuator element 1110 may
interact with the polarization of plate 1114, thereby compelling
first actuator element 1110 and plate 1114 to move toward each
other. Arranging first actuator element 1110 and plate 1114 in
relatively close proximity with each other may cause a magnetic
force to move first actuator element 1110 and plate 1114 toward
each other.
[0076] In FIG. 11, pin 1112 is moved through hole 804a of die plate
802 based on an electromagnetic stimulus. In embodiments, prior to
actuation, pin 1112 may reside outside of hole 804a (as shown in
FIG. 11) or may reside partially in hole 804a.
[0077] In the embodiment of FIG. 11, a second actuator element 1130
provides the electromagnetic stimulus (e.g., an electromagnetic
field) for actuator 1150. For example, second actuator element 1130
may be a commercial off-the-shelf (COTS) solenoid or a custom
designed solenoid. In FIG. 11, second actuator element 1130
includes windings 1108 around a tubular core 1106. Tubular core
1106 of second actuator element 1130 may have any cross-sectional
shape (e.g., circular, square, rectangle, etc.).
[0078] Current (e.g., direct-current (DC) current) flows through
windings 1108, generating the electromagnetic stimulus that
stimulates actuator 1150. In the embodiment of FIG. 11,
electromagnetic stimulation of actuator 1150 causes actuator 1150
to be moved toward die plate 802. For example, the electromagnetic
stimulus may be associated with a magnetic force that counteracts
the magnetic property of actuator 1150. The magnetic force may be
an electromagnetic force, for instance.
[0079] In the embodiment of FIG. 11, application of the
electromagnetic stimulus to actuator 1150 causes actuator 1150 to
move pin 1112 through hole 804a, thereby pushing die 104a from
surface 806 toward contact areas 210a-b. Thus, in an embodiment,
current through windings 1108 causes first actuator element 1110 to
move toward die plate 802, while a lack of current (or a reversal
of current) causes actuator 1110 to move pin 1112 through hole
804a. In an alternative embodiment, current flowing through
windings 1108 causes plate 1114 and actuator 1150 to be in contact
with each other, and a disruption in the current flow causes
actuator 1150 to move toward die plate 802, thereby moving pin 1112
through hole 804a.
[0080] According to an embodiment, the electromagnetic field
generated by second actuator element 1130 maintains die plate 802
in contact with pin plate 1104. For example, the force of the
electromagnetic field may be used to move die plate 802 and pin
plate 1104 toward each other. The magnitude of the electromagnetic
force is based on the amplitude of the current that flows through
windings 1108. For instance, a current having a relatively high
magnitude produces an electromagnetic force having a relatively
high magnitude. A current having a relatively low magnitude
produces an electromagnetic force having a relatively low
magnitude. In another example, the electromagnetic field may
inhibit or prevent die plate 802 from detaching from pin plate 1104
when pin 1112 detaches die 104a from die plate 802.
[0081] According to an embodiment, solenoid in FIG. 11 has a radius
of 0.16'' or less, and a height, h, in a range from 0.25'' to
0.4''. In an embodiment, the alignment of pin 1112 to hole 804a has
a tolerance of 1 mil or less.
[0082] FIG. 12 shows actuator 1150 moving pin 1112 through hole
804a to detach die 104a from bottom surface 1116 of die plate 802,
according to an example embodiment of the present invention.
Actuator 1150 moves pin 1112 based on the electromagnetic stimulus
generated by current flowing through windings 1108 of second
actuator element 1130. In FIG. 12, pin 1112 moves die 104a to
contact with substrate 1204a.
[0083] In embodiments, pin plate 1104 may include a plurality of
actuators 1150, to transfer a plurality of dies simultaneously. For
example, FIG. 13 shows system 1100 of FIG. 11 having a plurality of
actuators 1150a-b, according to an example embodiment of the
present invention. In FIG. 13, current flows through windings
1108a-b to stimulate respective first actuator elements 1110a-b,
causing respective pins 1112a-b to transfer respective dies 104a
and 104d from die plate 802. According to an embodiment, first
actuator elements 1110a-b provide a known and/or controllable force
to respective dies 104a and 104d. For example, each first actuator
element 1110a-b may provide substantially the same predetermined
force to respective pins 1112a-b, even if pins 1112a-b have
different lengths.
[0084] Referring to FIG. 13, actuators 1110a-b may be stimulated
simultaneously, consecutively, or selectively. For example, current
may flow through windings 1108a-b at the same time or at different
times.
[0085] In an embodiment, a computer system is used to control
systems of the present invention. For example, the computer system
may be configured to control movement of a die plate holder to
position die plate 802 adjacent to substrate 1102. Furthermore, the
computer system may be configured to control a substrate supply,
which may be supplying substrates singly or in web format (i.e.,
sheets or continuous roll of substrates). Still further, the
computer system may be configured to control a stimulus source, to
actuate the stimulus, and to direct the stimulus to various
positions on die plate 802 to cause dies 104 to be transferred
therefrom.
[0086] Furthermore, FIG. 13 also shows an adhesive material 1302a
adhering contact pads 204 of die 104a to the corresponding contact
areas 210 on the first surface of substrate 1204a. In an
embodiment, adhesive material 1302 can be cured or otherwise
treated to cause a die 104 to adhere to a substrate 1204. For
example, the current that is applied to windings 1108a-b to cause
respective actuators 1110 to move toward substrate 1102 may be
maintained during the curing cycle. A pin 1112 can hold a
respective die 104 in place with a predetermined force while
adhesive material 1302 is cured using ultraviolet (UV) radiation,
for example.
[0087] According to an embodiment, the electric and/or magnetic
field generated by a second actuator element 1130 over time can be
controlled, to maintain a downward force as desired for a
particular application. For example, the electric and/or magnetic
field generated by second actuator element 1130 can be controlled
to avoid damaging integrated circuit dies, or to avoid causing
first actuator element 1110 to become separated from pin plate
1104.
[0088] In another embodiment, pin 1112 is not included in first
actuator element 1110. For example, pin 1112 may be included in a
plate that is provided between first actuator element 1110 and die
plate 802. In this embodiment, first actuator element 1110 comes
into contact with pin 1112 based on an electromagnetic stimulus,
thereby moving pin 1112 through hole 804a to remove die 104a from
die plate 802.
[0089] In yet another embodiment, first actuator element 1110 may
be coupled to plate 1114 via a spring, and/or a spring may be
present between head 1122 and the top surface of pin plate 1104,
around the body of first actuator element 1110. For example, the
spring may contract in a steady state condition and extend in
response to an electromagnetic stimulus. In another example, the
spring may be extended in a steady state condition and contracted
in response to the electromagnetic stimulus.
3.0 Other Embodiments
[0090] FIGS. 1-13 are conceptual illustrations allowing an easy
explanation of transferring die(s) from an intermediate surface to
a substrate. It should be understood that embodiments of the
present invention can be implemented in hardware, firmware,
software, or a combination thereof. In such an embodiment, the
various components and steps are implemented in hardware, firmware,
and/or software to perform the functions of the present invention.
That is, the same piece of hardware, firmware, or module of
software can perform one or more of the illustrated blocks (i.e.,
components or steps).
[0091] In this document, the terms "computer program medium" and
"computer usable medium" are used to generally refer to media such
as a removable storage unit, a hard disk installed in hard disk
drive, and signals (i.e., electronic, electromagnetic, optical, or
other types of signals capable of being received by a
communications interface). These computer program products are
means for providing software to a computer system. The invention,
in an embodiment, is directed to such computer program
products.
[0092] In an embodiment where aspects of the present invention are
implemented using software, the software may be stored in a
computer program product and loaded into computer system using a
removable storage drive, hard drive, or communications interface.
The control logic (software), when executed by a processor, causes
the processor to perform the functions of the invention as
described herein.
[0093] According to an embodiment, a computer executes
computer-readable instructions to control the release of die(s)
from an intermediate surface, such as die plate 802, to a
substrate. For instance, a roll of substrate material may be
provided. The computer controls stimulation or actuation to cause
one or more dies to be released from the intermediate surface to a
first portion of the substrate. The roll of substrate may be
advanced to provide a second portion of the substrate. The computer
controls stimulation or actuation to cause one or more dies to be
released from the intermediate surface to the second portion of the
substrate, and so on. In an embodiment, the computer executes
instructions to selectively actuate the actuator.
[0094] In another embodiment, aspects of the present invention are
implemented primarily in hardware using, for example, hardware
components such as application specific integrated circuits
(ASICs). Implementation of the hardware state machine so as to
perform the functions described herein will be apparent to one
skilled in the relevant art(s).
[0095] In yet another embodiment, the invention is implemented
using a combination of both hardware and software.
4.0 Conclusion
[0096] While various embodiments of the present invention have been
described above, it should be understood that they have been
presented by way of example, and not limitation. It will be
apparent to persons skilled in the relevant arts that various
changes in form and detail can be made therein without departing
from the spirit and scope of the invention. Thus the present
invention should not be limited by any of the above-described
exemplary embodiments, but should be defined only in accordance
with the following claims and their equivalents.
* * * * *