U.S. patent application number 12/136565 was filed with the patent office on 2008-11-06 for method, system, and apparatus for transfer of dies using a die plate.
This patent application is currently assigned to Symbol Technologies. Invention is credited to Michael R. Arneson, William R. Bandy.
Application Number | 20080271313 12/136565 |
Document ID | / |
Family ID | 33551754 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080271313 |
Kind Code |
A1 |
Arneson; Michael R. ; et
al. |
November 6, 2008 |
METHOD, SYSTEM, AND APPARATUS FOR TRANSFER OF DIES USING A DIE
PLATE
Abstract
A method, system, and apparatus for transfer of dies using a die
plate is described herein. The die plate has a planar body. The
body has a plurality of holes therethrough. A support structure and
the die plate can be positioned to be closely adjacent to each
other such that each die of a plurality of dies attached to the
support structure adheres to a first surface of the die plate. The
dies can subsequently be transferred from the die plate to one or
more destination substrates or other surfaces, by a punching
mechanism.
Inventors: |
Arneson; Michael R.;
(Westminister, MD) ; Bandy; William R.;
(Gambrills, MD) |
Correspondence
Address: |
STERNE, KESSLER, GOLDSTEIN & FOX P.L.L.C.
1100 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
Symbol Technologies
|
Family ID: |
33551754 |
Appl. No.: |
12/136565 |
Filed: |
June 10, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10866253 |
Jun 14, 2004 |
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12136565 |
|
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60477735 |
Jun 12, 2003 |
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Current U.S.
Class: |
29/832 ;
29/417 |
Current CPC
Class: |
H01L 24/81 20130101;
H01L 2924/01013 20130101; H01L 2924/3025 20130101; Y10T 29/49165
20150115; G11B 23/0042 20130101; H01L 21/68 20130101; H01L
2924/01079 20130101; H01L 2924/09701 20130101; H01L 2924/00014
20130101; H01L 2924/01005 20130101; H01L 2924/01033 20130101; H01L
2924/01006 20130101; Y10T 29/49155 20150115; Y10T 156/1179
20150115; Y10T 29/49018 20150115; Y10T 156/1978 20150115; Y10T
29/53178 20150115; Y10T 156/1983 20150115; Y10T 156/1906 20150115;
H01L 2221/68354 20130101; H01L 2221/68322 20130101; H01L 2924/01075
20130101; H01L 2224/16 20130101; H01L 2924/12042 20130101; Y10T
29/4913 20150115; H01L 2924/01039 20130101; H01L 24/75 20130101;
Y10T 29/49124 20150115; H01L 24/95 20130101; Y10T 156/1142
20150115; Y10T 29/5327 20150115; H01L 2924/01047 20130101; H01L
2224/83192 20130101; H01L 2924/01057 20130101; H01L 2924/014
20130101; Y10T 29/53187 20150115; G06K 19/077 20130101; Y10T
29/53422 20150115; H01L 2224/81801 20130101; H01L 2924/19042
20130101; Y10T 29/49117 20150115; H01L 2924/19041 20130101; G11B
7/26 20130101; H01L 2224/75 20130101; H01L 21/6835 20130101; Y10T
29/49798 20150115; Y10S 438/976 20130101; H01L 2924/3011 20130101;
H01L 21/67144 20130101; H01L 21/67132 20130101; H01L 2924/19043
20130101; Y10T 29/49126 20150115; G06K 7/0095 20130101; G11B
23/0021 20130101; H01L 2924/12042 20130101; Y10T 29/49833 20150115;
H01L 2924/14 20130101; Y10T 156/1075 20150115; G06K 19/07718
20130101; H01L 21/78 20130101; H01L 2224/0401 20130101; H01L
2223/54473 20130101; H01L 2924/00 20130101; H01L 2924/00014
20130101; G06K 19/041 20130101; G06K 19/045 20130101 |
Class at
Publication: |
29/832 ;
29/417 |
International
Class: |
H05K 3/30 20060101
H05K003/30 |
Claims
1. A method for transferring a plurality of integrated circuit dies
that are attached to a support structure to a die plate,
comprising: (a) positioning the support structure and die plate to
be closely adjacent to each other such that each die of a plurality
of dies attached to the support structure adheres to a first
surface of the die plate due to an adhesive material; and (b)
releasing each die of the plurality of dies from the support
structure so that each die remains attached to the die plate.
2. The method of claim 1, wherein step (b) comprises: moving apart
the support structure and die plate.
3. The method of claim 2, wherein said moving step comprises:
moving apart the support structure and die plate so that each die
remains attached to the die plate due to the adhesive material
overcoming an adhesiveness of the support structure.
4. The method of claim 2, wherein step (a) comprises: positioning
the support structure and die plate to be closely adjacent to each
other such that each die of the plurality of dies covers a
corresponding hole through the die plate, wherein each hole is open
at the first surface and second surface of the die plate.
5. The method of claim 4, further comprising: (c) applying a
suction at a second surface of the die plate that further adheres
each die to the die plate due to the corresponding hole.
6. The method of claim 1, further comprising: (c) applying the
adhesive material to the first surface of the die plate.
7. The method of claim 1, wherein a first surface of each die is
attached to the support structure, further comprising: (c) applying
the adhesive material to a second surface of each die of the
plurality of dies.
8. The method of claim 2, wherein the support structure is a tape
structure, wherein said moving step comprises: peeling the support
structure from the die plate.
9. A method for transferring a plurality of integrated circuit dies
from a wafer to a die plate, comprising: (a) positioning the wafer
and die plate to be closely adjacent to each other such that the
wafer adheres to a first surface of the die plate due to an
adhesive material, wherein the die plate includes a plurality of
holes, wherein each hole is open at the first surface and a second
surface of the die plate, wherein each die of a plurality of dies
of the wafer covers a corresponding hole through the die plate; and
(b) separating each die of the plurality of dies from the wafer so
that each die remains on the die plate.
10. The method of claim 9, wherein step (b) comprises: sawing each
die of the plurality of dies from the wafer.
11. The method of claim 10, wherein said sawing step comprising:
sawing along grooves in the first surface of the die plate that are
positioned at boundaries between adjacent dies of the plurality of
dies of the wafer.
12. The method of claim 9, further comprising: (c) applying a
suction at a second surface of the die plate that further adheres
the wafer to the die plate due to the plurality of holes.
13. The method of claim 9, further comprising: (c) applying the
adhesive material to the first surface of the die plate.
14. The method of claim 9, further comprising: (c) applying the
adhesive material to a surface of the wafer.
15. The method of claim 9 wherein step (b) comprises: using a laser
to separate each die of the plurality of dies from the wafer.
16. A method for transferring a plurality of integrated circuit
dies, comprising: (a) forming grooves in a first surface of a
support structure that attaches a plurality of dies, wherein the
grooves are formed in the surface of the support structure between
the dies; and (b) moving a second surface of the support structure
and a die plate into contact with each other so that the support
structure attaches to the die plate, and so that a portion of the
support structure attaching each die of the plurality of dies
covers a corresponding hole through the die plate.
17. The method of claim 16, wherein the plurality of dies are
included in a wafer, wherein step (a) comprises: cutting through
the wafer to separate the dies from the wafer and to form the
grooves in the surface of the support structure.
18. The method of claim 16, wherein the plurality of dies are
separate on the support structure, wherein step (a) comprises:
forming the grooves in the surface of the support structure through
channels between the dies.
19. The method of claim 16, further comprising: (c) applying a
positive pressure to the support structure to reduce sag in the
support structure.
20. The method of claim 16, further comprising: (c) punching
through at least one hole through the die plate to transfer a
corresponding die from the die plate to a destination surface.
21. The method of claim 20, wherein step (c) comprises: tearing the
support structure around the corresponding die to release the die
from the support structure, wherein a portion of the support
structure remains attached to the die.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. Non-Provisional
application Ser. No. 10/866,253, filed Jun. 14, 2004, which claims
the benefit of U.S. Provisional Application No. 60/477,735, filed
Jun. 12, 2003, all of which are herein incorporated by reference in
their entirety as if reproduced in full below.
[0002] The following applications of common assignee are related to
the present application, have the same filing date (Jun. 14, 2004)
as the parent application, and are herein incorporated by reference
in their entirety as if reproduced in full below:
[0003] "Method And Apparatus For Expanding A Semiconductor Wafer,"
U.S. Ser. No. 10/866,148, now U.S. Pat. No. 7,223,320;
[0004] "Method, System, And Apparatus For Authenticating Devices
During Assembly," U.S. Ser. No. 10/866,152, now U.S. Pat. No.
7,276,388;
[0005] "Method, System, And Apparatus For Transfer Of Dies Using A
Die Plate Having Die Cavities," U.S. Ser. No. 10/866,150, U.S.
Patent Publication No. 2005-0009232, published Jan. 13, 2005;
[0006] "Method, System, And Apparatus For Transfer Of Dies Using A
Pin Plate," U.S. Ser. No. 10/866,159, U.S. Patent Publication No.
2005-0015970, published Jan. 27, 2005;
[0007] "Method, System, And Apparatus For High Volume Transfer Of
Dies," U.S. Ser. No. 10/866,149, U.S. Patent Publication No.
2005-0005434, published Jan. 13, 2005; and
[0008] "Method, System, And Apparatus For High Volume Assembly Of
Compact Discs And Digital Video Discs Incorporating Radio Frequency
Identification Tag Technology," U.S. Ser. No. 10/866,151, U.S.
Patent Publication 2004-0251541, published Dec. 16, 2004.
[0009] The following applications of common assignee are related to
the present application, and are herein incorporated by reference
in their entirety as if reproduced in full below:
[0010] "Method and Apparatus for High Volume Assembly of Radio
Frequency Identification Tags," U.S. Provisional App. No.
60/400,101, filed Aug. 2, 2002;
[0011] "Method and Apparatus for High Volume Assembly of Radio
Frequency Identification Tags," Ser. No. 10/322,467, filed Dec. 19,
2002, now U.S. Pat. No. 7,117,581;
[0012] "Multi-Barrel Die Transfer Apparatus and Method for
Transferring Dies Therewith," Ser. No. 10/322,718, filed Dec. 19,
2002, now U.S. Pat. No. 6,915,551;
[0013] "Die Frame Apparatus and Method of Transferring Dies
Therewith," Ser. No. 10/322,701, filed Dec. 19, 2002, now U.S. Pat.
No. 7,102,524;
[0014] "System and Method of Transferring Dies Using an Adhesive
Surface," Ser. No. 10/322,702, filed Dec. 19, 2002, now U.S. Pat.
No. 6,848,162; and
[0015] "Method and System for Forming a Die Frame and for
Transferring Dies Therewith," Ser. No. 10/429,803, filed May 6,
2003, now U.S. Pat. No. 7,023,347.
BACKGROUND OF THE INVENTION
[0016] 1. Field of the Invention
[0017] 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.
[0018] 2. Related Art
[0019] 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.
[0020] 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.
[0021] 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."
[0022] 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
[0023] The present invention is directed to methods, systems, and
apparatuses for producing one or more electronic devices, such as
RFID tags, that each include a die having one or more electrically
conductive contact pads that provide electrical connections to
related electronics on a substrate.
[0024] According to the present invention, electronic devices are
formed at much 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.
[0025] In an aspect of the present invention, methods, systems, and
apparatuses for transfer of dies using the die plate are described
herein. The die plate has a planar body. The body has a plurality
of holes therethrough.
[0026] In a further aspect, a support structure and the die plate
can be positioned to be closely adjacent to each other such that
each die of a plurality of dies attached to the support structure
adheres to a first surface of the die plate. The dies can
subsequently be transferred from the die plate to one or more
destination substrates or other surfaces, by a punching or other
mechanism.
[0027] In an aspect, a punch plate, punch roller or cylinder, or
expandable material can be used to transfer dies from the die plate
to substrates.
[0028] Large quantities of dies can be transferred. For example, 10
s, 100 s, 1000 s, or more dies, or even all dies of a wafer,
support surface, or die plate, can be simultaneously transferred to
corresponding substrates of a web.
[0029] In one aspect, dies may be transferred between surfaces in a
"pads up" orientation. When dies are transferred to a substrate in
a "pads up" orientation, related electronics can be printed or
otherwise formed to couple contact pads of the die to related
electronics of the tag substrate.
[0030] In an alternative aspect, the dies may be transferred
between surfaces in a "pads down" orientation. When dies are
transferred to a substrate in a "pads down" orientation, related
electronics can be pre-printed or otherwise pre-deposited on the
tag substrates.
[0031] 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
[0032] 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.
[0033] FIG. 1A shows a block diagram of an exemplary RFID tag,
according to an embodiment of the present invention.
[0034] FIGS. 1B and 1C show detailed views of exemplary RFID tags,
according to embodiments of the present invention.
[0035] FIGS. 2A and 2B show plan and side views of an exemplary
die, respectively.
[0036] FIGS. 2C and 2D show portions of a substrate with a die
attached thereto, according to example embodiments of the present
invention.
[0037] FIG. 3 is a flowchart illustrating a tag assembly process,
according to embodiments of the present invention.
[0038] FIGS. 4A and 4B are plan and side views of a wafer having
multiple dies affixed to a support surface, respectively.
[0039] FIG. 5 is a view of a wafer having separated dies affixed to
a support surface.
[0040] FIG. 6 shows a system diagram illustrating example options
for transfer of dies from wafers to substrates, according to
embodiments of the present invention.
[0041] FIGS. 7 and 8 show flowcharts providing steps for
transferring dies from a first surface to a second surface,
according to embodiments of the present invention.
[0042] FIG. 9 shows a perspective view of an example die plate,
according to an example embodiment of the present invention.
[0043] FIGS. 10A-10E show multiple schematic views of an example
die plate, according to an embodiment of the present invention.
[0044] FIG. 11 shows a perspective view of a portion of a surface
of a die plate, according to an embodiment of the present
invention.
[0045] FIG. 12 shows a flowchart providing example steps for
transferring dies from a support structure to a die plate,
according to embodiments of the present invention.
[0046] FIGS. 13-15 show example implementations of the steps of the
flowchart of FIG. 12, according to embodiments of the present
invention.
[0047] FIG. 16 shows a flowchart providing example steps for
transferring dies from a wafer to a die plate, according to
embodiments of the present invention.
[0048] FIGS. 17-19 show example implementations of the steps of the
flowchart of FIG. 16, according to embodiments of the present
invention.
[0049] FIGS. 20-26 show various views of a transfer of dies to a
die plate, and subsequently to one or more substrates, according to
embodiments of the present invention.
[0050] FIG. 27 shows a flowchart providing steps for transferring
dies, according to embodiments of the present invention.
[0051] 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
[0052] 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. 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.
[0053] 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.
[0054] 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. Current techniques process 5-8 thousand units per hour.
The present invention can provide 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.
[0055] Elements of the embodiments described herein may be combined
in any manner. Example RFID tags are described in the section
below. Assembly embodiments for RFID tags are described in the next
section. Example applications for tags and tag assembly techniques
are then described, followed by a description of example substrate
webs and antenna layouts.
1.0 RFID Tag
[0056] 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.
[0057] FIG. 1A shows a block diagram of an exemplary RFID tag 100,
according to an embodiment of the present invention. As shown in
FIG. 1A, 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. FIGS. 1B and 1C
show detailed views of exemplary RFID tags 100, indicated as RFID
tags 100a and 100b. As shown in FIGS. 1B and 1C, 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.
[0058] 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.
[0059] 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.
[0060] 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 on Feb. 12, 2002, both of
which are incorporated by reference herein in its entirety. Die 104
includes a plurality of contact pads that each provide an
electrical connection with related electronics 106.
[0061] 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.
[0062] As shown in FIGS. 1A-1C, 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..
[0063] In some implementations of tags 100, tag substrate 116 can
include an indentation, "cavity," or "cell" (not shown in FIGS.
1A-1C) that accommodates die 104. An example of such an
implementation is included in a "pads up" orientation of die
104.
[0064] 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).
[0065] 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
adherement. 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.
[0066] 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.
2.0 RFID Tag Assembly
[0067] 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.
[0068] 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.
[0069] 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 300, 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.
[0070] 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.
[0071] 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-1 that indicate locations where dies 104 are separated.
[0072] 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.
[0073] 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.
[0074] 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. Example embodiments where dies
104 of a wafer 400 are separated, and simultaneously transferred to
a subsequent surface, are described below.
[0075] In a step 310, post processing is performed. During step
310, assembly of RFID tag(s) 100 is completed.
2.1 Die Transfer Embodiments
[0076] 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.
[0077] 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.
[0078] 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 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. For
example, as shown in FIG. 6, first path 602 leads directly from
wafer 400 to web 608. In other words, dies can be transferred from
wafer 400 to substrates of web 608 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 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, 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.
[0079] FIGS. 7 and 8 show flowcharts providing steps for
transferring dies from a first surface to a second surface,
according to embodiments of the present invention. Structural
embodiments of the present invention will be apparent to persons
skilled in the relevant art(s) based on the following discussion.
These steps are described in detail below.
[0080] Flowchart 700 begins with step 702. In step 702, a plurality
of dies attached to a support surface is received. For example, the
dies are dies 104, which are shown attached to a support surface
404 in FIG. 4A. For example, the support surface can be a "green
tape" or "blue tape" as would be known to persons skilled in the
relevant art(s).
[0081] In step 704, the plurality of dies are transferred to a
subsequent surface. For example, dies 104 may be transferred
according to embodiments of the present invention. For example, the
dies may be transferred by an adhesive tape, a punch tape, a
multi-barrel transport mechanism and/or process, die frame, pin
plate, such as are further described below and/or in the
incorporated patent applications, and may be transferred by other
mechanisms and processes, or by combinations of the
mechanisms/processes described herein. In embodiments, the
subsequent surface can be an intermediate surface or an actual
final substrate. For example, the intermediate surface can be a
transfer surface, including a "blue tape," as would be known to
persons skilled in the relevant art(s). When the subsequent surface
is a substrate, the subsequent surface may be a substrate structure
that includes a plurality of tag substrates, or may be another
substrate type.
[0082] In block 706, if the subsequent surface is a substrate to
which the dies are going to be permanently attached, the process of
flowchart 700 is complete. The process can then proceed to step 310
of flowchart 300, if desired. If the subsequent surface is not a
final surface, then the process proceeds to step 704, where the
plurality of dies are then transferred to another subsequent
surface. Step 704 may be repeated as many times as is required by
the particular application.
[0083] Flowchart 800 of FIG. 8 is substantially similar to
flowchart of 700. However, instead of including step 702, flowchart
800 includes step 802. In step 802, a wafer that includes a
plurality of dies is received. Thus, in flowchart 800, a wafer 400
is operated on directly, without being applied to a support surface
or structure. Embodiments for both of flowcharts 700 and 800 are
described herein.
[0084] 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.
[0085] The die transfer processes described herein include transfer
using an adhesive surface, a parallel die punch process, die
plates, including die receptacle structures, pin plates, die
transfer heads, and die transfer head coverage patterns. 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). These die transfer processes, and related example
structures for performing these processes, are further described in
the following subsections.
[0086] 2.1.1 Die Transfer onto a Die Plate
[0087] According to an embodiment of the present invention, a die
plate is used for transferring dies from wafers or support surfaces
to substrates or subsequent transfer services. According to die
plate embodiments described herein, dies 104 can be attached to a
surface of the die plate, being positioned over a corresponding
hole of the die plate. Once a die is transferred to the die plate,
the die can then be transferred to subsequent,
intermediate/transfer surfaces, or to a final surface or structure,
such as a substrate.
[0088] FIG. 9 shows an example die plate 900, according to an
example embodiment of the present invention. As shown in FIG. 9,
die plate 900 includes a body 902. As shown in FIG. 9, body 902 is
substantially planar. Body 902 can be manufactured using materials
including a metal or combination of metals/alloy, a polymer, a
plastic, glass, other materials, and any combination thereof.
Furthermore, as shown in FIG. 9, body 902 has a plurality of
openings or holes 906 formed therethrough. Holes 906 are open at
both the top and bottom planar surfaces of body 902. Although holes
906 are shown in FIG. 9 as being substantially round or elliptical,
they can have other shapes, including square or rectangular, or
other shape.
[0089] FIGS. 10A-E show example schematic views of die plate 900,
according to an example embodiment. For example, FIG. 10A shows a
die plate 900, and shows the outline of a wafer 400 superimposed on
top of die plate 900. FIG. 10B also shows a die plate portion 1010
showing a close-up view of a surface of die plate 900. As shown for
portion 1010, die plate 900 has a plurality of holes 906, and in
this particular embodiment, includes a plurality of grid lines
1002. Grid lines 1002 can be formed on either or both of the bottom
and top surfaces of die plate 900. Grid lines 1002 can be used to
indicate areas for placement of dies 104 on die plate 900 and/or
can be used as guidelines for sawing or otherwise separating dies
104 on die plate 1002. For example, grid lines 1002 can be grooves
in the surface of die plate 900 for an end of a saw blade to pass
through. FIG. 10C also shows a plan view of a die plate portion
1020.
[0090] FIG. 11 shows a perspective view of a die plate portion
1100, according to an embodiment of the present invention. As shown
in FIG. 11, die plate portion 1100 includes holes 906, and grid
lines 1002, which are shown as grooves in the surface of die plate
900.
[0091] FIG. 12 shows example steps related to a flowchart 1200 for
transferring dies from a support structure to die plate 900,
according to embodiments of the present invention. Further
operational and structural embodiments of the present invention
will be apparent to persons skilled in the relevant arts based on
the following discussion.
[0092] FIGS. 13-15 relate to the steps of flowchart 1200 of FIG.
12. FIG. 13 shows a plurality of dies 104 attached in a pads-down
fashion to a bottom surface of a support structure 404. FIG. 13
also shows a cross-sectional view of die plate 900. As shown in
FIG. 13, an adhesive material layer 1302 has been formed on the top
surface of die plate 900. Note that additionally or alternatively,
an adhesive material can be applied to the bottom surfaces of dies
104. Adhesive material layer 1302 may be any type of adhesive
material, including an epoxy, an adhesive tape, or any other
adhesive material.
[0093] FIG. 14 shows an implementation of step 1202 of flowchart
1200 shown in FIG. 12. As shown in FIG. 14, support structure 404
and die plate 900 are positioned closely adjacent to each other,
such that each die 104 attached to support structure 404 adheres to
the top surface of die plate 900 due to adhesive material layer
1302.
[0094] FIG. 15 shows an example implementation of step 1204 of
flowchart 1200 shown in FIG. 12. As shown in FIG. 15, each die 104
is released from support surface 404, and therefore remains
attached to die plate 900. In an embodiment, for example, the
adhesive force of adhesive material layer 1302 is stronger than the
adhesive force of the bottom surface of support structure 404.
Thus, when support structure 404 is moved away from die plate 900,
dies 104 remain attached to die plate 900. Thus, support structure
may be peeled from die plate 900 to transfer dies 104.
[0095] Note that although a vacuum source is not shown or used in
FIGS. 13-15, in an alternative embodiment, a vacuum source can be
used in the current embodiment to aid in transferring dies 104 to
die plate 900.
[0096] In further embodiments, dies 104 of a wafer 400 can be
directly transferred to die plate 900. FIG. 16 shows example steps
related to a flowchart 1600 for transferring dies from a wafer to
die plate 900, according to embodiments of the present invention.
Further operational and structural embodiments of the present
invention will be apparent to persons skilled in the relevant arts
based on the following discussion.
[0097] FIGS. 17-19 relate to the steps of flowchart 1600 shown in
FIG. 16. For example, FIG. 17 shows an example wafer having a
plurality of dies included therein, being positioned adjacent to a
die plate 900. Note that in an embodiment, wafer 400 has been
thinned so that it has a thickness of approximately the thickness
of a die. Furthermore, as shown in FIG. 17, an adhesive material
layer 1302 has been applied to the top surface of die plate 900.
Note that additionally, or alternatively, an adhesive material may
be applied to the bottom surface of wafer 400.
[0098] FIG. 18 shows an example implementation of step 1602 of
flowchart 1600 shown in FIG. 16. As shown in FIG. 18, wafer 400 and
die plate 900 are positioned closely adjacent to each other such
that wafer 400 adheres to the first surface of die plate 900. Note
that die plate 900 and wafer 400 are positioned such that each die
104 of wafer 400 covers a corresponding hole 906 through die plate
900 at the first or top surface of die plate 900.
[0099] FIG. 19 shows an example implementation of step 1604 of
flowchart 1600 shown in FIG. 16. As shown in FIG. 19, each of dies
104 are scribed/separated from wafer 400 so that they remain
attached to the top surface of die plate 900. For example, as shown
in FIGS. 18 and 19, a saw mechanism 1802 can be used to separate
the dies 104 of wafer 400. The blade of saw mechanism 1802 may
track the grooves or lines of grid 1002 which can be optionally
formed in the top surface of die plate 900. Saw mechanism 1802 can
be a saw blade or other cutting device, can be a laser, or any
other sawing or cutting device suitable for separating dies from a
wafer 400.
[0100] 2.1.1.1 Die Transfer onto a Die Plate from Partially Cut
Adhesive Surface
[0101] FIGS. 20-26 show various views of a transfer of dies to a
die plate, and subsequently to one or more substrates, according to
embodiments of the present invention. FIG. 20 shows a wafer 400
attached in a pads-up fashion to a surface of a support structure
404. For example, wafer 400 and support structure 400 may be held
in a conventional wafer frame or other holding mechanism. As shown
in FIG. 20, a first die 104 is being separated from wafer 400. For
example, as shown in FIG. 20, a saw mechanism 1802 (or other
suitable device or process) can be used to scribe/separate die 104
of wafer 400. Furthermore, saw mechanism 1802 penetrates and
cuts/separates a groove depth 2002 of the total thickness 2004 of
support structure 404 when separating first die 104a from wafer
400, to form grooves 2006. Groove depth 2002 can be any portion of
the thickness 2004 of support structure 404, as required by the
particular application. As shown in FIG. 20, groove depth 2002 can
be greater than 50% of thickness 2004, including approximately 90%
of thickness 2004.
[0102] Note that although FIG. 20 shows dies 104 being separated
when grooves 2006 are formed, in another embodiment, dies 104 may
already have been separated before grooves 2006 are formed. Thus,
in such an embodiment, grooves 2006 may be formed in a subsequent
processing step to the actual scribing of wafer 400. Thus, the
present application is applicable to using scribed and un-scribed
wafers.
[0103] FIG. 21 shows wafer 400 having a plurality of dies 104a-d
separated, with grooves 2006a-e formed in support structure 404
around each of the plurality of dies 104. Furthermore, FIG. 21
shows wafer 400 being positioned adjacent to a die plate 900 in
preparation for transfer of dies 104 to die plate 900. Note that
because grooves 2006 penetrate support structure 404 around each
die 104, potentially weakening support structure 404, support
structure 404 may sag when being positioned adjacent to die plate
900. Such sagging of support structure 404 may create difficulties
in precisely aligning dies 104 over corresponding holes 906 through
die plate 900. Thus, if groove depth 2002 is great enough to cause
significant sagging of support structure 404, a vacuum and/or
positive pressure may be used to reduce or eliminate the sagging.
For example, FIG. 22 shows a pressure source 2202 used to provide a
positive pressure. For example pressure source 2202 provides a gas
pressure 2204 directed through holes 906 of die plate 900 to reduce
sag in support structure 404 when support structure 404 and die
plate 900 are being moved into contact. Alternatively or
additionally, a vacuum source may be applied to support structure
404 (e.g., from above support structure 404 in FIG. 22) to provide
a vacuum/suction to reduce sag in support structure 404.
[0104] FIG. 23 shows support structure 404 and die plate 900
positioned closely adjacent to each other such that support
structure 404 adheres to the first surface of die plate 900. Note
that die plate 900 and wafer 400 are positioned such that each of
dies 104a-d covers a corresponding hole 906a-d through die plate
900 at the first or top surface of die plate 900.
[0105] FIG. 24 shows a close up view of a die 104a of FIG. 23,
where die plate 900 attaching support structure 404 and dies 104
has been inverted. As shown in FIG. 24, a pin 2402 is inserted in
hole 906a to be used to push/punch die 104a from die plate 900.
FIG. 25 shows pin 2402 moving through hole 906a of die plate 900 to
contact support structure 404 opposite of die 104a, to push die
104a in contact with a substrate 2502. Pin 2402 separates die 104a
from support structure 404 by tearing/ripping support structure 404
around the perimeter of die 104a, such as at perimeter portions
2504a and 2504b in FIG. 24 (an adhesiveness of substrate 2502 may
also contribute to this tearing/ripping of support structure
404).
[0106] Note that pin 2402 may be coupled to a pin plate having a
plurality of pins 2402 that push/punch a plurality of dies 104 from
die plate 900 in parallel onto the same or multiple substrates. For
example, in a multiple substrate embodiment, the substrates may be
separate, or joined together in a web of substrates. For further
information on example pin plates, refer to co-pending U.S.
application Ser. No. ______, titled "Method, System, And Apparatus
For Transfer Of Dies Using A Pin Plate," having the same filing
date as the present application, which is incorporated by reference
in its entirety herein.
[0107] FIG. 26 shows die 104a on substrate 2502, having been
separated from support structure 404 by pin 2402. As shown in FIG.
26 portion 2602 of support structure 404 remains attached to die
104a. Portion 2602 of support structure 404 helps to protect die
104a from damage due to pin 2402 during transfer of die 104 to
substrate 2502. Portion 2602 attached to die 104a can subsequently
be removed from die 104a if desired, or can remain on die 104a when
the respective tag or other device including substrate 2502 is
completed. For example, portion 2602 can remain on die 104a to
provide environmental protection for die 104a.
[0108] FIG. 27 shows a flowchart providing steps for transferring
dies, according to embodiments of the present invention. For
example, FIG. 27 relates to the transfer of dies shown in FIGS.
20-26. Further structural embodiments of the present invention will
be apparent to persons skilled in the relevant art(s) based on the
following discussion. These steps are described in detail
below.
[0109] In step 2702, grooves are formed in a first surface of a
support structure that attaches a plurality of dies. For example,
the grooves are grooves 2006 formed in support structure 404, as
shown in FIGS. 20-25. Note that the dies attached to the support
structure may be separate on the support structure, or included in
a wafer, prior to formation of the grooves.
[0110] In step 2704, a second surface of the support structure and
a die plate are moved into contact with each other so that the
support structure attaches to the die plate. For example, as shown
in FIG. 23, the bottom surface of support structure 404 is moved
into contact with die plate 900, to become attached to die plate
900. Note that in an embodiment, as described above, a positive
pressure can be applied to the support structure to reduce sag in
the support structure.
[0111] In an embodiment, flowchart 2700 includes step 2706. In step
2706, at least one hole through the die plate is punched through to
transfer a corresponding die from the die plate to a destination
surface. For example, as shown in FIGS. 24 and 25, pin 2402 passes
through hole 906a to transfer die 104a from die plate 900 to
substrate 2502. Note that in an embodiment, the support structure
around the corresponding die is torn to release the die from the
support structure. In an embodiment, a portion of the support
structure remains attached to the die.
[0112] 2.1.2 Example Die Plate Embodiments
[0113] As described above, FIGS. 10A-E show example schematic views
of die plate 900, according to an illustrative embodiment of the
present invention. As described above, a die plate can be made from
a variety of materials. In an embodiment, a die plate is made from
the same material as a corresponding pin plate is made, or from a
material having the same coefficient of thermal expansion (CTE) as
a corresponding pin plate, so that the die plate and pin plate will
expand and contract uniformly due to changes in temperature. For
example, a die plate and corresponding pin plate can be from
aluminum. In another example, one of the die plate and
corresponding pin plate are made from Kapton, while the other is
made from aluminum, because Kapton and aluminum have very similar
CTE values. Alternatively, both can be made from Kapton.
[0114] As described above, FIG. 10A shows a die plate 900, and
shows the outline of a wafer 400 superimposed on top of die plate
900. Die plate 900 can have any shape and size, as required by a
particular application. For example, die plate 900 shown in FIG.
10A can have a width and length of approximately 254 mm. Wafer 400
can have a diameter of approximately 203 mm, for example. Die plate
900 can have holes 906 spaced according to any distances, as
required by a particular application. For example, in one
embodiment, die plate 900 can have a hole pattern of 103.times.205
holes spaced apart 2 mm horizontally and 1 mm vertically for a
total number of 21,115 holes (e.g., for rectangular die). Such a
pattern can cover a 204 mm.times.204 mm pattern (from hole center
to hole center).
[0115] FIG. 10C shows a plan view of a die plate portion 1020.
Holes 906 can have any diameter, as required by a particular
application. Typically, holes 906 have a diameter less than or
equal to a minimum of the width and length of a corresponding die.
For example, hole 906 shown in FIG. 10C can have a diameter of
approximately 0.584 mm to accommodate a die having a width of
approximately 0.949 mm and a length of approximately 1.949 mm.
FIGS. 10D and 10E show cross-sectional views of portions of die
plate 900. Grooves 1002 can have any widths and depths, as required
by a particular application. For example, grooves 1002 shown in
FIGS. 10D and 10E can have widths of approximately 0.051 mm and
depths of approximately 0.051 mm.
[0116] It is noted that any of the sizes/dimensions, spacings,
numbers of holes, etc., described above are provided for
illustrative purposes. It will be apparent to persons skilled in
the relevant art(s) that these parameters can be modified as needed
for a particular application. For example, these parameters can be
modified for particular wafer sizes, die sizes, number of dies to
be transferred in parallel, etc.
CONCLUSION
[0117] 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.
* * * * *