U.S. patent application number 11/266208 was filed with the patent office on 2007-05-17 for method and system for high volume transfer of dies to substrates.
This patent application is currently assigned to Symbol Technologies, Inc.. Invention is credited to David Addison, Travis Steinmetz.
Application Number | 20070107186 11/266208 |
Document ID | / |
Family ID | 38039228 |
Filed Date | 2007-05-17 |
United States Patent
Application |
20070107186 |
Kind Code |
A1 |
Addison; David ; et
al. |
May 17, 2007 |
Method and system for high volume transfer of dies to
substrates
Abstract
A method, system, and apparatus for transferring dies to
respective substrates is described. 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 or consecutively. Dies are loaded in a channel of a
die application device. The dies are moved through the channel
using any of a variety of means, such as gravity, air, vibration, a
brush, a spring, etc. The die application device dispenses the dies
onto respective substrates. In an aspect, the die application
device independently dispenses each of the dies. In another aspect,
the die application device dispenses multiple dies at a time.
Inventors: |
Addison; David; (Baltimore,
MD) ; Steinmetz; Travis; (New Market, 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: |
38039228 |
Appl. No.: |
11/266208 |
Filed: |
November 4, 2005 |
Current U.S.
Class: |
29/428 |
Current CPC
Class: |
Y10T 29/49826 20150115;
H01L 21/6838 20130101; H01L 21/67144 20130101; H01L 2224/10
20130101 |
Class at
Publication: |
029/428 |
International
Class: |
B21D 39/03 20060101
B21D039/03 |
Claims
1. A method of transferring dies to respective substrates,
comprising: loading a plurality of dies in a channel of a die
application device; and dispensing the dies onto respective
substrates.
2. The method of claim 1, further comprising: moving the plurality
of dies through the channel to align at least one die of the
plurality of dies with a surface of a die application element of
the die application device.
3. The method of claim 2, wherein moving the plurality of dies
includes pushing the dies with air.
4. The method of claim 2, wherein moving the plurality of dies is
performed using a vacuum.
5. The method of claim 2, wherein moving the plurality of dies
includes vibrating the plurality of dies.
6. The method of claim 2, wherein moving the plurality of dies
includes carrying the plurality of dies on a guide of the die
application device toward a die application element of the die
application device.
7. The method of claim 2, wherein moving the plurality of dies is
performed using a spring.
8. The method of claim 2, wherein moving the plurality of dies is
performed using a brush.
9. The method of claim 1, wherein dispensing the dies includes
independently dispensing each die of the plurality of dies.
10. The method of claim 1, wherein dispensing the dies includes
actuating a die application element of the die application device
using a servo-controlled linear drive.
11. The method of claim 1, wherein dispensing the dies includes
actuating a die application element of the die application device
using an electromechanical solenoid.
12. The method of claim 1, further comprising: tacking the dies
onto the respective substrates using pressure.
13. The method of claim 1, further comprising: bonding the dies
onto the respective substrates using pressure and heat.
14. An apparatus to transfer dies to respective substrates,
comprising: a body having a channel that is configured to receive a
plurality of dies; and a die application element that is configured
to transfer dies of the plurality of dies to respective
substrates.
15. The apparatus of claim 14, further comprising a guide coupled
to the body, wherein a combination of the guide and the body
laterally surrounds at least a portion of the channel.
16. The apparatus of claim 15, wherein the body and the guide are a
unitary element.
17. The apparatus of claim 14, wherein the die application element
is provided in an opening of the body.
18. The apparatus of claim 14, wherein the die application element
is configured to move along an axis that is substantially
perpendicular to an axis of the channel.
19. The apparatus of claim 14, wherein the die application element
is configured to move along a first axis and the channel is
configured along a second axis, and wherein the first axis and the
second axis are configured at an angle that enables gravity to
facilitate movement of the plurality of dies toward die application
element.
20. The apparatus of claim 14, wherein the die application element
is configured to transfer a single die at a time.
21. The apparatus of claim 14, wherein the die application element
is configured to transfer multiple dies at a time.
22. The apparatus of claim 14, further comprising: a second die
application element that is configured to transfer dies of a second
plurality of dies to respective substrates, wherein the body
further has a second channel that is configured to receive the
second plurality of dies.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to the assembly of
electronic devices. More particularly, the present invention
relates to the transfer of dies from wafers to substrates,
including substrates of radio frequency identification (RFID)
tags.
[0003] 2. Related Art
[0004] 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) 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.
[0005] 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.
[0006] 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."
[0007] As market demand increases for products such as RFID tags,
and as die sizes shrink, high assembly throughput rates for very
small die, and low production costs are crucial in providing
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
[0008] The present invention is directed to methods, systems, and
apparatuses for transferring dies to respective substrates. A die
application device includes a body and a die application element.
The body has a channel that is configured to receive a plurality of
dies. The die application element is configured to transfer dies of
the plurality of dies to respective substrates. In an aspect, the
die application device includes a guide coupled to the body. A
combination of the guide and the body laterally surround at least a
portion of the channel. In an aspect, the guide and the body are a
unitary element.
[0009] The die application element is configured to move along a
first axis. The channel is configured along a second axis. The
first axis and the second axis are typically perpendicular to each
other.
[0010] In a first example, the die application element is
configured to transfer a single die at a time. In a second example,
the die application element is configured to transfer multiple dies
at a time.
[0011] The die application device includes any number of cavities
and/or die application elements. In an aspect, the die application
device includes a plurality of cavities, each of which is capable
of receiving a plurality of dies. Each channel is associated with a
respective die application element. Die application elements are
actuated independently from each other or in synchronism.
[0012] In another aspect of the present invention, dies are loaded
in a channel of the die application device. The dies are moved
through the channel to align at least one die with a die pedestal
of the die application element. The die application element
dispenses the dies onto respective substrates. The dies may be
bonded onto the respective substrates.
[0013] These and other advantages and features will become readily
apparent in view of the following detailed description of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES
[0014] 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.
[0015] FIG. 1 shows a block diagram of an exemplary RFID tag,
according to an embodiment of the present invention.
[0016] FIGS. 2A and 2B show plan and side views of an exemplary
die, respectively.
[0017] FIGS. 2C and 2D show portions of a substrate with a die
attached thereto, according to example embodiments of the present
invention.
[0018] FIG. 3 is a flowchart illustrating a tag assembly process,
according to embodiments of the present invention.
[0019] FIGS. 4A and 4B are plan and side views of a wafer having
multiple dies affixed to a support surface, respectively.
[0020] FIG. 5 is a view of a wafer having separated dies affixed to
a support surface.
[0021] FIG. 6 shows a system diagram illustrating example options
for transfer of dies from wafers to substrates, according to
embodiments of the present invention.
[0022] FIG. 7A shows a cross-sectional side view of a die
application device, according to an embodiment of the present
invention.
[0023] FIG. 7B shows a front view of the die application device of
FIG. 7A, according to an embodiment of the present invention.
[0024] FIGS. 8A and 8B show perspective views of an example die
application device, according to embodiments of the present
invention.
[0025] FIGS. 9A-9C show side views of an example die application
device, according to embodiments of the present invention.
[0026] FIGS. 10A-10C show side views of an example die application
device, according to embodiments of the present invention.
[0027] FIG. 11 illustrates a flowchart of a method of transferring
dies to respective substrates in accordance with an embodiment of
the present invention.
[0028] 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
[0029] This specification discloses one or more embodiments that
incorporate the features of this invention. The embodiment(s)
described, and references in the specification to "one embodiment",
"an embodiment", "an example embodiment", etc., indicate that the
embodiment(s) described may include a particular feature,
structure, or characteristic, but every embodiment may not
necessarily include the particular feature, structure, or
characteristic. Moreover, such phrases are not necessarily
referring to the same embodiment. Furthermore, when a particular
feature, structure, or characteristic is described in connection
with an embodiment, it is submitted that it is within the knowledge
of one skilled in the art to effect such feature, structure, or
characteristic in connection with other embodiments whether or not
explicitly described.
1.0 Overview
[0030] The present invention provides improved processes and
systems for assembling electronic devices, including RFID tags. The
present invention provides improvements over current 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 or consecutively.
Vision-based systems are limited as far as the size of dies that
may be handled, such as being limited to dies larger than 600
microns square. The present invention is applicable to dies 100
microns square 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.
[0031] 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. Furthermore, because the present invention allows for
flip-chip die attachment techniques, wire bonds are not necessary.
Elements of the embodiments described herein may be combined in any
manner.
[0032] 1.1 Example Electronic Device
[0033] 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 description is also adaptable
to the production of further electronic device types, as would be
understood by persons skilled in the relevant art(s) from the
teachings herein.
[0034] 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. As is further described
elsewhere herein, die 104 may be mounted in either a pads up or
pads down orientation.
[0035] RFID tag 100 may be located in an area having a large
number, population, or pool of RFID tags present. RFID tag 100
receives interrogation signals transmitted by one or more tag
readers. According to interrogation protocols, RFID tag 100
responds to these signals. Each response includes information that
identifies the corresponding RFID tag 100 of the potential pool of
RFID tags present. Upon reception of a response, the tag reader
determines the identity of the responding tag, thereby ascertaining
the existence of the tag within a coverage area defined by the tag
reader.
[0036] RFID tag 100 may be used in various applications, such as
inventory control, airport baggage monitoring, as well as security
and surveillance applications. Thus, RFID 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. RFID tag 100 enables
location monitoring and real time tracking of such items.
[0037] 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. entitled
System and Method for Electronic Inventory, and U.S. patent
application Ser. No. 10/072,885 filed Feb. 12, 2002 entitled
Method, System, and Apparatus for Binary Traversal of a Tag
Population. Die 104 includes a plurality of contact pads that each
provide an electrical connection with related electronics 106.
[0038] 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, sensor functionality,
power reception and storage functionality, as well as additional
capabilities. The 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 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.
[0039] 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 or
backing can be included on the second surface. When present, the
adhesive backing enables tag 100 to be attached to objects, such as
books 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..
[0040] 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.
[0041] 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 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 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 and solder flux. Such post processing, or
"bumping," will be known to persons skilled in the relevant
art(s).
[0042] 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
connection. This arrangement allows for a range of tolerance 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.
[0043] Note that although FIGS. 2A-2D show the layout of four
contact pads 204a-d collectively forming a rectangular shape,
greater or lesser numbers of contact pads 204 may be used.
Furthermore, contact pads 204a-d may be laid out in other shapes in
embodiments of the present invention.
[0044] 1.2 Device Assembly
[0045] The present invention is directed to continuous-roll
assembly techniques and other techniques for assembling tags, such
as RFID tag 100. Such techniques involve a continuous web (or roll)
of the material of the tag antenna substrate 116 that is capable of
being separated into a plurality of tags. Alternatively, separate
sheets of the material can be used as discrete substrate webs that
can be separated into a plurality of tags. As described herein, the
manufactured one or more tags can then be post processed for
individual use. For illustrative purposes, the techniques described
herein are made with reference to assembly of 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.
[0046] 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.
[0047] 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. Process 300
begins with a step 302. In step 302, a wafer 400 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
104 are arranged in a plurality of rows 402a-n.
[0048] 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. FIG. 4B shows an example view of wafer 400
in contact with an example support surface 404. In some
embodiments, wafer 400 does not need to be attached to a support
surface, and can be operated on directly.
[0049] In a step 306, the plurality of dies 104 on wafer 400 are
separated. For example, step 306 may include scribing wafer 400
according to a process, such as laser etching. 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. In an
embodiment, wafer 400 is only scribed in one direction, so that
separated strips (e.g., rows or columns) of dies are formed.
[0050] 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 toward
(and in contact with) tag substrate 116. In an embodiment, as
described below, dies are transferred using a die application
device that holds the strips of dies formed in step 306.
[0051] 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.
[0052] 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. In a step 310, post processing
is performed. During step 310, assembly of RFID tag(s) 100 is
completed.
2.0 Die Transfer Embodiments
[0053] Step 308 shown in FIG. 3, and discussed above, relates to
transferring dies to a tag substrate. The dies can be attached to a
support surface (e.g., as shown in FIG. 5), or can be transferred
directly from the wafer, and can be transferred to the tag
substrate by a variety of techniques. Conventionally, the transfer
is accomplished using a pick and place tool. The pick and place
tool uses a vacuum die collet controlled by a robotic mechanism
that picks up the die from the support structure by a suction
action, and holds the die securely in the die collet. The pick and
place tool deposits the die into a die carrier or transfer surface.
For example, a suitable transfer surface is a "punch tape"
manufactured by Mulbauer, Germany. A disadvantage of the present
pick and place approach is that only one die at a time may be
transferred. Hence, the present pick and place approach does not
scale well for very high throughput rates.
[0054] The present invention allows for the transfer of more than
one die at a time from a support surface to a transfer surface. In
fact, the present invention allows for the transfer of more than
one die between any two surfaces, including transferring dies from
a wafer or support surface to an intermediate surface, transferring
dies between multiple intermediate surfaces, transferring dies
between an intermediate surface and the final substrate surface,
and transferring dies directly from a wafer or support surface to
the final substrate surface.
[0055] 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 web of
substrates 606, and a transfer surface 608. 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. For example, as shown in FIG. 6, first path 602 leads
directly from wafer 400 to web 606. In other words, dies can be
transferred from wafer 400 to substrates of web 606 directly,
without the dies having first to be transferred from wafer 400 to
another surface or storage structure. However, according to 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 608. The dies then are transferred
from transfer surface 608 via path 604B to the substrates of web
606. Paths 602 and 604 each have their advantages. For example,
path 602 can have fewer steps, 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 608 can make die transfer to the
substrates of web 606 easier, as die registration may be
easier.
[0056] According to embodiments of the present invention, a die
application tool or device is used to transfer dies to surfaces,
such as substrates, including substrates of a web.
[0057] FIG. 7A shows a cross-sectional side view of a die
application device 700, according to an example embodiment of the
present invention. FIG. 7B shows a front view of die application
device 700, according to an embodiment of the present invention.
Die application device 700 is used to transfer dies 104 to
surfaces, such as substrates 116. As shown in FIGS. 7A and 7B, die
application device 700 includes a body 710. Body 710 has length 702
shown in FIG. 7A, and a width 704 shown in FIG. 7B. Body 710 has a
channel 706 formed in a top surface 708 along length 702. Channel
706 is a groove or slot in top surface 708 configured to hold a row
or column of integrated circuit chips or dies during operation of
die application device 700.
[0058] As shown in FIGS. 7A and 7B, body 710 further includes a
guide chamber 712, which is open at a side surface 714 of body 710,
and also at top surface 708, where top surface 708 intersects with
side surface 714. Guide chamber 712 has a rectangular shape, and is
configured to contain and guide a die application element 730
during operation of die application device 700. As shown in FIGS.
7A and 7B, die application element 730 resides in guide chamber
712, and is moveable along an axis 716.
[0059] Die application element 730 has a die pedestal 718. During
operation of die application device 700, a die in channel 706 is
moved from channel 706 onto die pedestal 718. The position of the
die relative to die pedestal 718 is maintained by any of a variety
of means, such as a vacuum. Die application element 730 is actuated
in a first direction (shown as an upward direction in FIGS. 7A and
7B) along axis 716 through guide chamber 712 to move the die in the
first direction. The die is thereby made accessible from die
application device 700, and can be applied to a subsequent surface
or otherwise utilized.
[0060] For instance, FIGS. 8A-8B show example operation of die
application device 700. FIGS. 8A-8B show perspective views of die
application device 700 during operation, according to embodiments
of the present invention. As shown in FIG. 8A, a row of dies 104
are present in channel 706. Furthermore, dies 104 in channel 706
have been incremented such that a first die 104a is positioned on
die pedestal 718 of die application element 730. As shown in FIG.
8B, die application element 730 has been actuated, to move upward
along axis 716. Die 104a can be transferred from die pedestal 718
to a subsequent surface. In FIGS. 8A-8B, a cover plate 802 is
coupled to top surface 708 for illustrative purposes. Cover plate
802 encloses channel 706, thereby securing dies 104 that are moved
along channel 706 toward die pedestal 718.
3.0 Other Embodiments
[0061] Die application device 700 is capable of being operated in
any orientation. For instance, FIGS. 9A-9C show perspective views
of die application device 700 oriented to transfer dies 104
downward onto surfaces, such as substrates. In FIG. 9A, channel 706
is open at a bottom surface 908 of body 710. Die application device
700 includes a guide 902 coupled to bottom surface 908 of body 710
to provide structural support for dies 104 that are moved through
channel 706 toward die pedestal 718.
[0062] Referring to FIG. 9A, the combination of guide 902 and body
710 laterally surrounds at least a portion of channel 706. The term
"laterally surround" as used herein means to "define a perimeter
of". The laterally surrounded portion of channel 706 is referred to
as being enclosed, though not all sides of channel 706 need to be
surrounded or covered. For example, channel 706 may have a
cylindrical shape with one or both ends being uncovered. In this
example, the enclosed portion is the entire channel 706. According
to an embodiment, body 710 and guide 902 are a unitary element.
[0063] Channel 706 may be configured to receive dies in any of a
variety of arrangements. In a first aspect, channel 706 is
configured to receive a linear array of dies. The linear array
includes a single row or column of dies or multiple rows or columns
of dies. In a second aspect, channel 706 is configured to receive a
random or pseudo-random arrangement of dies. For instance, dies 104
may be moved to a corner or a relatively narrow portion of channel
706 to orient at least one of the dies 104 relative to die
application element 730.
[0064] Channel 706 is provided between walls of body 710. In a
first embodiment, the walls are substantially parallel. In a second
embodiment, the distance between the walls decreases toward die
application element 730. Channel 706 has a proximal end and a
distal end with respect to die application element 730. In the
second embodiment, the walls are closer to each other at the
proximal end than at the distal end.
[0065] As shown in FIG. 9B, dies 104 are moved through channel 706
in a direction indicated by arrow 940. In FIG. 9B, dies 104 are
moved substantially parallel with bottom surface 908 of body 710,
though the scope of the present invention is not limited in this
respect. Dies 104 are moved through channel 706 in any of a variety
of ways. According to a first embodiment, air is used to push
and/or a vacuum is used to pull dies 104 along guide 902. In a
second embodiment, vibration is used to facilitate moving dies 104.
According to a third embodiment, body 710 and guide 902 are not
necessarily fixably attached to each other. In an aspect, guide 902
moves with reference to body 710 in the direction indicated by
arrow 940 until guide 902 reaches a threshold or an obstacle. The
obstacle may be coupled to body 710 along surface 908, for
instance. In another aspect, dies 104 rest upon guide 902 as guide
902 moves along surface 908 of body 710. In a fourth embodiment, a
lever, an arm, and/or a spring is used to move dies 104 in the
direction indicated by arrow 940. The lever, arm, and/or spring is
coupled to body 710 or guide 902. According to a fifth embodiment,
a brush is used to move dies 104 through channel 706. The brush is
moved in the direction indicated by arrow 940, such that the brush
is placed in contact with one or more dies 104, thereby moving one
or more dies 104 along guide 902.
[0066] Referring to FIG. 9B, die 104a is aligned with die pedestal
718 for transfer to a respective substrate. In FIG. 9B, one die
104a at a time is aligned with pedestal 718 for illustrative
purposes. Any number of dies 104 may be aligned with pedestal 718
of die application element 730. As shown in FIG. 9C, die
application element 730 is actuated in a direction indicated by
arrow 950, thereby making die 104a accessible from die application
device 700. Die application element 730 is actuated by any of a
variety of means, such as an electromechanical solenoid or a
servo-controlled linear drive.
[0067] Upon transferring die 104a to a substrate, die application
element 730 moves in a direction opposite that indicated by arrow
950. Dies 104 that remain in channel 706 are incremented in a
direction indicated by arrow 940 of FIG. 9B to align the next
successive die with die pedestal 718 of die application element
730. Die application element 730 is again actuated in the direction
indicated by arrow 950, such that the die that is aligned with die
pedestal 718 is transferred to a respective substrate. This process
can be repeated for any number of dies 104.In FIGS. 10A-10C, die
application device 700 is configured to transfer more than one die
104 at a time from channel 706. For example, in FIG. 10A, die
application device 730 is capable of transferring five dies 104 at
a time FIG. 10B, dies 104 are moved in the direction indicated by
arrow 940, so that dies 104a-e are aligned with die pedestal 718 of
die application element 730. Five dies 104a-e are aligned with
surface 735 for illustrative purposes. Any number of dies may be
aligned with die pedestal 718. In FIG. 10C, die application element
730 is moved in the direction indicated by arrow 750, thereby
transferring dies 104a-e from channel 706.
[0068] FIG. 11 illustrates a flowchart 1100 of a method of
transferring dies to respective substrates in accordance with an
embodiment of the present invention. The invention, however, is not
limited to the description provided by the flowchart 1100. Rather,
it will be apparent to persons skilled in the relevant art(s) from
the teachings provided herein that other functional flows are
within the scope and spirit of the present invention.
[0069] Flowchart 1100 will be described with continued reference to
example die application device 700 described above in reference to
FIGS. 7A-10C, though the method is not limited to those
embodiments.
[0070] Referring now to FIG. 11, a plurality of dies 104 is loaded
in a channel 706 of a die application device 700 at block 1110.
According to an embodiment, a wafer includes a plurality of rows,
each row having a plurality of dies. A row of the wafer is loaded
in channel 706 of die application device 700.
[0071] The plurality of dies 104 are moved through channel 706 to
align at least one die of the plurality of dies 104 with a die
pedestal 718 of die application device 700. The plurality of dies
104 may be moved by pushing or pulling the dies 104 using air, by
vibrating the dies 104, or by any other means. In an aspect, the
dies 104 are moved using a mechanical means, such as a spring, a
brush, or a guide 902 that can move independently from a body 710
of die application device 700. For example, guide 902 carries the
dies 104 toward die application element 730 for dispensing.
[0072] Die application device 700 dispenses the dies 104 onto
respective substrates 116 at block 1120. In a first embodiment, die
application device 700 independently dispenses each die of the
plurality of dies 104. In a second embodiment, die application
device 700 dispenses multiple dies at a time.
[0073] Die application device 700 includes any number of channels
706 and/or die application elements 730. According to an
embodiment, die application device 700 includes a plurality of
channels 706, each of which is capable of receiving a plurality of
dies 104. Dies in each channel 706 are moved as described above
with respect to FIGS. 7A-10C. Each channel 706 is associated with a
respective die application element 730. A first die is aligned with
a first surface of a first die application element, a second die is
aligned with a second surface of a second die application element,
and so on. The die application elements are actuated independently
from each other or in synchronism.
4.0 Conclusion
[0074] 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.
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