US20050005434A1

US20050005434A1 - Method, system, and apparatus for high volume transfer of dies

Info

Publication number: US20050005434A1
Application number: US10/866,149
Authority: US
Inventors: Michael Arneson; William Bandy
Original assignee: Matrics Inc
Current assignee: Symbol Technologies LLC
Priority date: 2003-06-12
Filing date: 2004-06-14
Publication date: 2005-01-13
Also published as: US20080271313A1; TW200504809A; US20050007252A1; US7543316B2; WO2004112096A2; US20040250949A1; US20060174257A1; US7223320B2; US20050009232A1; US20050015970A1; US7276388B2; US7404199B2; US20040251541A1; EP1642325A2; US7795076B2; WO2004112096A3; US20040250417A1

Abstract

A system, method and apparatus for die transfer using a changeable or movable material is described herein. The die plate has a planar body. The body has a plurality of holes therethrough. Each die covers a corresponding hole on a first surface of the die plate. The holes are filled with a material that can be caused to expand, exert pressure, or move when exposed to one or more stimuli. The die plate is positioned to be closely adjacent to the web of substrates. The dies can subsequently be transferred from the die plate to one or more destination substrates or other surfaces by applying one or more stimuli to the material, causing the material to expand, exert pressure, or move. The action of the material causes the dies to separate from the die plate.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/477,735, filed Jun. 12, 2003 (Atty. Dkt. No. 1689.0350000), which is herein incorporated by reference in its entirety.
The following applications of common assignee are related to the present application, have the same filing date as the present application, and are herein incorporated by reference in their entireties:
“Method And Apparatus For Expanding A Semiconductor Wafer,” U.S. Ser. No. ______ (Atty. Dkt. No. 1689.0520000);

- “Method, System, And Apparatus For Authenticating Devices During Assembly,” U.S. Ser. No. ______ (Atty. Dkt. No. 1689.0530000);
- “Method, System, And Apparatus For Transfer Of Dies Using A Die Plate Having Die Cavities,” U.S. Ser. No. ______ (Atty. Dkt. No. 1689.0540000);
- “Method, System, And Apparatus For Transfer Of Dies Using A Die Plate,” U.S. Ser. No. ______ (Atty. Dkt. No. 1689.0550000);
- “Method, System, And Apparatus For Transfer Of Dies Using A Pin Plate,” U.S. Ser. No. ______ (Atty. Dkt. No. 1689.0560000); and

“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. ______ (Atty. Dkt. No. 1689.0590000).
The following applications of common assignee are related to the present application, and are herein incorporated by reference in their entireties:
“Method and Apparatus for High Volume Assembly of Radio Frequency Identification Tags,” U.S. Provisional App. No. 60/400,101, filed Aug. 2, 2002 (Atty. Dkt. No. 1689.0110000);

- “Method and Apparatus for High Volume Assembly of Radio Frequency Identification Tags,” Ser. No. 10/322,467, filed Dec. 19, 2002 (Atty. Dkt. No. 1689.0110001);
- “Multi-Barrel Die Transfer Apparatus and Method for Transferring Dies Therewith,” Ser. No. 10/322,718, filed Dec. 19, 2002 (Atty. Dkt. No. 1689.0110002);
- “Die Frame Apparatus and Method of Transferring Dies Therewith,” Ser. No. 10/322,701, filed Dec. 19, 2002 (Atty. Dkt. No. 1689.0110003);
- “System and Method of Transferring Dies Using an Adhesive Surface,” Ser. No. 10/322,702, filed Dec. 19, 2002 (Atty. Dkt. No. 1689.0110004); and

“Method and System for Forming a Die Frame and for Transferring Dies Therewith,” Ser. No. 10/429,803, filed May 6, 2003 (Atty. Dkt. No. 1689.0110005).

BACKGROUND OF THE INVENTION

1. Field of the Invention
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.
2. Related Art
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.
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.
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.”
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

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.
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.
In an aspect, a punch plate, punch roller or cylinder, or a changeable or movable material can be used to transfer dies from the die plate to substrates.
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.
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.
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.
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

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.
FIG. 1A shows a block diagram of an exemplary RFID tag, according to an embodiment of the present invention.
FIGS. 1B and 1C show detailed views of exemplary RFID tags, according to embodiments of the present invention.
FIGS. 2A and 2B show plan and side views of an exemplary die, respectively.
FIGS. 2C and 2D show portions of a substrate with a die attached thereto, according to example embodiments of the present invention.
FIG. 3 is a flowchart illustrating a device assembly process, according to embodiments of the present invention.
FIGS. 4A and 4B are plan and side views of a wafer having multiple dies affixed to a support surface, respectively.
FIG. 5 is a view of a wafer having separated dies affixed to a support surface.
FIG. 6 shows a system diagram illustrating example options for transfer of dies from wafers to substrates, according to embodiments of the present invention.
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.
FIG. 9 shows a flowchart providing example steps for transferring dies using an expandable material, according to embodiments of the present invention.
FIGS. 10-13 show example implementations of the steps of the flowchart of FIG. 9, according to embodiments of the present invention.
FIG. 14 shows a flowchart providing example steps for transferring dies directly from a support structure to a substrate, according to embodiments of the present invention
FIGS. 15-19 show example implementations of the steps of the flowchart of FIG. 14, according to embodiments of the present invention.
The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.

DETAILED DESCRIPTION OF THE INVENTION

1. Overview
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. 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.
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.
Elements of the embodiments described herein may be combined in any manner. Example RFID tags are described in section 1.1. Assembly embodiments for devices are described in section 1.2.
1.1 Exemplary Electronic Device
The present invention is directed to techniques for producing electronic devices, such as RFID tags. For illustrative purposes, the description herein primarily relates to the production of RFID tags. However, the invention is also adaptable to the production of further electronic device types, as would be understood by persons skilled in the relevant art(s) from the teachings herein.
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 100 a and 10 b. 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.
FIG. 1B depicts an exemplary tag 100A having a rectangular substrate 116. As shown in FIG. 1B, the exemplary antenna 114 on substrate 116 extends for 50.75 mm in the x direction and 19 mm in the y direction. As would be appreciated by persons skilled in the art, different dimensions and configurations can be used for antenna 114 and substrate 116.
FIG. 1C depicts an exemplary tag 100B having a circular substrate 116. Exemplary antenna 114 on substrate 116 also has a substantially circular geometry. As shown in FIG. 1C, exemplary antenna 114 fits within a circle having a diameter of approximately 35 mm.
RFID tag 100, such as the exemplary tags shown in FIGS. 1A-1C, 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.
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.
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.
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.
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®.
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.
FIGS. 2A and 2B show plan and side views of an example die 104. Die 104 includes four contact pads 204 a-d that provide electrical connections between related electronics 106 (not shown) and internal circuitry of die 104. Note that although four contact pads 204 a-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).
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 204 a-d of die 104 are coupled to respective contact areas 210 a-d of substrate 116. Contact areas 210 a-d provide electrical connections to related electronics 106. The arrangement of contact pads 204 a-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 204 a-d and contact areas 210 a-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 204 a-d and contact areas 210 a-d.
Note that although FIGS. 2A-2D show the layout of four contact pads 204 a-d collectively forming a rectangular shape, greater or lesser numbers of contact pads 204 may be used. Furthermore, contact pads 204 a-d may be laid out in other shapes in other embodiments.
1.2 Device Assembly
The present invention is directed to continuous-roll assembly techniques and other techniques for assembling electronic devices, such as RFID tag 100. Such techniques involve a continuous web (or roll) of the material of the substrate 116 that is capable of being separated into a plurality of devices. Alternatively, separate sheets of the material can be used as discrete substrate webs that can be separated into a plurality of devices. As described herein, the manufactured one or more devices can then be post processed for individual use. For illustrative purposes, the techniques described herein are made with reference to assembly of tags, such as RFID tag 100. However, these techniques can be applied to other tag implementations and other suitable devices, as would be apparent to persons skilled in the relevant art(s) from the teachings herein.
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.
FIG. 3 shows a flowchart 300 with example steps relating to continuous-roll production of RFID tags 100, according to example embodiments of the present invention. FIG. 3 shows a flowchart illustrating a process 300 for assembling tags 100. The process 300 depicted in FIG. 3 is described with continued reference to FIGS. 4A and 4B. However, process 300 is not limited to these embodiments.
Process 300 begins with a step 302. In step 302, a wafer 400 (shown in FIG. 4A) having a plurality of dies 104 is produced. FIG. 4A illustrates a plan view of an exemplary wafer 400. As illustrated in FIG. 4A, a plurality of dies 104 a-n are arranged in a plurality of rows 402 a-n.
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 is not attached to a support surface, and can be operated on directly.
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 502 a-1 that indicate locations where dies 104 are separated.
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 204 a-204 d facing away from tag substrate 116. In a “pads down” orientation for tag 100, die 104 is transferred to tag substrate 116 with pads 204 a-204 d facing towards, and in contact with tag substrate 116.
Note that step 308 may include multiple die transfer iterations. For example, in step 308, dies 104 may be directly transferred from a wafer 400 to substrates 116. Alternatively, dies 104 may be transferred to an intermediate structure, and subsequently transferred to substrates 116. Example embodiments of such die transfer options are described below in reference to FIGS. 6-8.
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 of the steps of flowchart 300, are described in co-pending applications, “Method and Apparatus for Expanding a Semiconductor Wafer,” (Atty. Dkt. 1689.0520000), “Method, System, and Apparatus for Transfer of Dies Using a Die Plate Having Die Cavities,” (Atty. Dkt. 1689.0540000), “Method, System, and Apparatus for Transfer of Dies Using a Die Plate,” (Atty. Dkt. 1689.0550000), “Method, System, and Apparatus for Transfer of Dies Using a Pin Plate,” (Atty. Dkt. 1689.056000), and “Method, System, and Apparatus for High Volume Transfer of Dies,” (Atty. Dkt. No. 1689.0580000), each of which is herein incorporated by reference in its entirety.
In a step 310, post processing is performed. For example, during step 310, assembly of RFID tag(s) 100 is completed.
FIGS. 6-8 further describe step 308 of FIG. 3. FIG. 6 shows a high-level system diagram 600 that provides a representation of the different modes or paths of transfer of dies from wafers to substrates. FIG. 6 shows a wafer 400, a substrate web 608, and a transfer surface 610. Two paths are shown in FIG. 6 for transferring dies, a first path 602, which is a direct path, and a second path 604, which is a path having intermediate steps.
For example, as shown in FIG. 6, first path 602 leads directly from wafer 400 to substrate web 608. In other words, dies can be transferred from wafer 400 to substrates of substrate web 608 directly, without the dies having first to be transferred from wafer 400 to another surface or storage structure. However, as shown in path 604, at least two steps are required, path 604A and path 604B. For path 604A, dies are first transferred from wafer 400 to an intermediate transfer surface 610. The dies then are transferred from transfer surface 610 via path 604B to the substrates of web 608. Paths 602 and 604 each have their advantages. For example, path 602 can have fewer steps than path 604, but can have issues of die registration, and other difficulties. Path 604 typically has a larger number of steps than path 602, but transfer of dies from wafer 400 to a transfer surface 610 can make die transfer to the substrates of web 808 easier, as die registration may be easier.
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.
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 as shown in FIG. 4A. For example, support surface 404 can be a “green tape” or “blue tape” as would be known to persons skilled in the relevant art(s).
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 or referenced 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 substrates, or may be another substrate type.
In step 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.
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 400 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.
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.
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.
2. Die Transfer to Substrates
2.1 Die Transfer from Intermediate Surface to Substrate Using Changeable or Movable Material
FIG. 9 shows a flowchart 900 of a method for transferring dies from an intermediate surface to a substrate using a changeable or movable material, according to embodiments of the present invention. The flowchart depicted in FIG. 9 is described with continued reference to FIGS. 10-13. However, flowchart 900 is not limited to those embodiments. Further operational and structural embodiments of the present invention will be apparent to persons skilled in the relevant arts based on the following discussion. Note that in alternative embodiments, steps shown in FIG. 9 can occur in an order other than that shown, and in some embodiments, not all steps shown are necessary.
Flowchart 900 begins at step 902 when a die plate is received that has a first surface having a plurality of dies attached thereto. The die plate has a plurality of holes extending from the first surface to a second surface. Each attached die covers a corresponding hole at the first surface of the die plate. Example embodiments of die plates are described in co-pending applications, “Method, System, and Apparatus for Transfer of Dies Using a Die Plate Having Die Cavities,” (Atty. Dkt. 1689.0540000) and “Method, System, and Apparatus for Transfer of Dies Using a Die Plate,” (Atty. Dkt. 1689.0550000), each of which is herein incorporated by reference in its entirety.
FIG. 10 shows a die plate 1000 having a plurality of dies 104 attached to a first surface of the die plate. As shown in FIG. 10, each die 104 covers a corresponding hole 1006 through die plate 1000 at the first surface of die plate 1000.
In step 904, each hole of the die plate is at least partially filled with a material. For example, the hole may be filled with a material that can be caused to expand, a material that can be caused to exert pressure in multiple directions, or a material that moves when exposed to a certain stimulus or stimuli.
For example, as shown in FIG. 11, each hole 1006 is at least partially filled with a material. For example, as shown in FIG. 11, hole 1006 a is filled with a material 1102. Material 1102 can be any material that can be caused to expand or contract when exposed to stimuli, including an epoxy, a plastic, a polymer, a glass, or other material or combination thereof. Alternatively, the material can be any material that can be caused to exert pressure in multiple directions or change positions when exposed to stimuli including a magnetic fluid, artificial muscle material, or other material or combination thereof.
In step 906, the die plate and one or more substrates are positioned to be closely adjacent to each other such that contact pads of each die of the plurality of dies are closely adjacent to corresponding contact areas on the first surface of the substrate(s).
For example, FIG. 12 shows a die plate 1000 and substrate 116 positioned to be closely adjacent to each other such that contact pads 204 a and 204 b of die 104 are closely adjacent to corresponding contact areas 210 on a first surface of substrate 116. Note that die plate 1000 and substrate 116 in various embodiments can be positioned to varying degrees of closeness to each other, including distances other than that shown in FIG. 12.
In step 908, a stimulus (or stimuli) is applied to the material to cause the material in each hole to release a corresponding die from the die plate. For example, the material can be caused to expand, exert pressure, or move in the hole. This action by the material releases each die of the plurality of dies from the die plate. Example stimuli that can be used are heating, application of a voltage, application of a force, or application of other stimulus or combination thereof. The stimulus used is determined based on the physics and/or characteristics of the material used to fill the holes of the die plate.
For example, FIG. 13 shows a exemplary material 1102 that is caused to expand in hole 1006 a. By expanding, material 1102 detaches die 104 a from the bottom surface of die plate 1000. Thus, die 104 a is moved by material 1102 to contact with substrate 116 a.
Note that in the example of FIG. 13, a laser 1202 is depicted that causes the material 1102 filling each hole to expand. Laser 1202 directs a beam towards material 1102, which heats material 1102 to cause it to expand. Note that in alternative embodiments, other methods may be used to cause material 1102 to expand. In this manner, an expandable material can be used to transfer dies from a die plate, in place of the use of punch pins of a pin plate.
Furthermore, FIG. 13 also shows an adhesive material 1212 a adhering contact pads 204 of die 104 to the corresponding contact areas 210 on the first surface of substrate 116 a. Thus, in an embodiment, the adhesive material 1212 a is cured or otherwise treated to cause die 104 a to adhere to substrate 116 a.
2.2 Direct Die Transfer
FIG. 14 shows a flowchart 1400 of a method for transferring dies directly from a support structure to a substrate, according to embodiments of the present invention. The flowchart depicted in FIG. 14 is described with continued reference to FIGS. 15-19. However, flowchart 1400 is not limited to those embodiments. Further operational and structural embodiments of the present invention will be apparent to persons skilled in the relevant arts based on the following discussion. Note that in alternative embodiments, steps shown in FIG. 14 can occur in an order other than that shown, and in some embodiments, not all steps shown are necessary. Further operational and structural embodiments of the present invention will be apparent to persons skilled in the relevant arts based on the following discussion.
For example, FIG. 15 shows a plurality of dies 104 attached to a support surface or support structure 404. FIG. 15 further shows a single substrate 116 a of a web 608.
Flowchart 1400 begins at step 1402 when the support structure and substrate are positioned to be closely adjacent to each other such that contact pads of a die attached to the support structure make contact with corresponding contact areas on a first surface of the substrate.
For example, FIG. 16 shows an example of a support structure 404 and substrate 116 a positioned closely adjacent to each other such that contact pads 204 of die 104 a make contact with corresponding contact areas 210 of substrate 116 of web 608.
In step 1404, the contact pads 204 of die 104 a are adhered to the corresponding contact areas 210 on the first surface of substrate 116 a by adhesive material 1212 a.
In step 1406, the die is released from the support structure so that the die remains attached to the substrate.
In an embodiment, dies are attached to a support structure by an adhesive material that can be caused to release the dies when heat is applied thereto. In this embodiment, in step 1406, heat is applied to a second surface of the support structure, opposite the die, to cause the die to release from the first surface of the support structure.
In an embodiment, a light source is used to release dies from the support structure. For example, FIG. 17 shows a light pipe 1702 being used to release dies from the support structure. Light pipe 1702 is applied to support structure 404 on a surface of support structure 404 opposite that to which die 104 a is attached. Light pipe 1702 can be any type of optical structure, such as an optical tube, optical fiber, including a communications optical fiber, that allows light to pass through. For example, FIG. 17 shows a light 1704 being emitted from light pipe 1702. In an embodiment light 1704 is ultraviolet light. Light 1704, however, can comprise other wavelengths of light. In the current embodiment, die 104 a is attached to support structure 404 by an adhesive material that can be caused to release die 104 when a light of a particular wavelength, such as ultraviolet light is applied thereto. Thus, as shown in FIG. 19, die 104 a can be released from support structure 404, whereby die 104 a remains attached to substrate 116 a of web 608, by the application of light 1704 from light pipe 1702.
In an embodiment, in step 1406, the support structure is moved apart from the substrate so that the dies remain attached to the substrate due to the adhesive material overcoming the adhesiveness of the support structure. For example, the adhesiveness of the adhesive material between the substrate and die is stronger than the adhesiveness of the adhesive material between the dies and the support structure.
In an embodiment, in step 1406, the support structure is peeled from the substrate.
Alternatively, or additionally, a component contacts support structure 404 to cause or aid the release of dies from the support structure. Thus, as shown in FIG. 18, an end of light pipe 1702 can be used to push through support structure 404 to cause die 104 a to come into contact with the contact areas of substrate 116 a. During this process, as described above, light 1704 causes die 104 a to be released from support structure 404, and to remain attached to substrate 116 a, as shown in FIG. 19.
In the embodiments described above, an adhesive material may be applied to the contact areas of the substrate and/or to a second surface of the dies, opposite the support structure.
3.0 Conclusion
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.

Claims

1. A method for transferring a plurality of integrated circuit dies from a die plate to a substrate, comprising:

(a) receiving a die plate that has a first surface having a plurality of dies attached thereto, wherein each die of the plurality of dies covers a corresponding hole through the die plate at the first surface of the die plate;

(b) at least partially filling each hole with a material;

(c) positioning the die plate and substrate to be closely adjacent to each other such that each die of a first plurality of dies is closely adjacent to a corresponding contact area on a first surface of the substrate; and

(d) applying one or more stimulus to the material filling each hole to cause each die of the first plurality of dies to be released from the die plate.

2. The method of claim 1, wherein step (d) includes:

heating the material filling each hole.

3. The method of claim 1, wherein step (d) includes:

applying a voltage to the material filling each hole.

4. The method of claim 1, wherein step (d) includes:

applying a force to the material filling each hole.

5. The method of claim 1, wherein the material can be caused to expand when exposed to one or more stimulus.

6. The method of claim 1, wherein the material can be caused to exert pressure in multiple directions when exposed to one or more stimulus.

7. The method of claim 1, wherein the material can be caused to move when exposed to one or more stimulus.

8. The method of claim 2, wherein said heating step includes:

using a laser to heat the hardened material.

9. The method of claim 1, further comprising:

(e) adhering each die of the first plurality of dies to the corresponding contact area on the first surface of the substrate.

10. A method for transferring an integrated circuit die that is attached to first surface of a support structure to a substrate, comprising:

(a) positioning the support structure and substrate to be closely adjacent to each other such that contact pads of a die attached to the support structure make contact with corresponding contact areas on a first surface of the substrate;

(b) allowing an adhesive material to adhere the contact pads of the die to the corresponding contact areas on the first surface of the substrate; and

(c) releasing the die from the support structure so that the die remains attached to the substrate.

11. The method of claim 10, wherein step (b) comprises:

curing the adhesive material.

12. The method of claim 10, wherein the support structure comprises an adhesive that releases when heated, wherein step (c) comprises:

applying heat to a second surface of the support structure that is opposite the die to cause the die to release from the first surface of the support structure.

13. The method of claim 10, wherein the support structure comprises an adhesive that is light releasable, wherein step (c) comprises:

using a laser to heat a second surface of the support structure that is opposite the die to cause the die to release from the first surface of the support structure.

14. The method of claim 10, wherein step (c) comprises:

moving apart the support structure and substrate.

15. The method of claim 14, wherein said moving step comprises:

moving apart the support structure and substrate so that the die remains attached to the substrate due to the adhesive material overcoming an adhesiveness of the support structure.

16. The method of claim 10, further comprising:

(d) applying the adhesive material to the contact areas of the substrate.

17. The method of claim 10, wherein a first surface of each die is attached to the support structure, further comprising:

(d) applying the adhesive material to a second surface of the die.

18. The method of claim 14, wherein the support structure is a tape structure, wherein said moving step comprises:

peeling the support structure from the substrate.