Assembling and handling edge interconnect packaging system

Abstract

A first microchip includes holes or sockets along or in a top face or surface of the first microchip and a second microchip includes nodules extending from a edge of the second microchip. The nodules of the second microchip are received in the holes or sockets along or in the top face or surface of the first microchip, whereupon the first and second microchips are positioned transverse or perpendicular to each other.

Claims

1. A microchip unit comprising: a first microchip including holes or sockets in a face of the first microchip, wherein said holes or sockets are spaced away from an edge of the first microchip; and a second microchip including nodules extending laterally from an edge of the second microchip; wherein the nodules of the second microchip are received in the holes or sockets in the face of the first microchip.

2. The microchip unit of claim 1, wherein the holes or sockets in the face of the first microchip are coated in solder.

3. The microchip unit of claim 1, wherein the first and second microchips are joined by solder between the nodules of the second microchip received in the holes or sockets in the face of the first microchip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The systems, devices, and methods may be better understood by referring to the following description in conjunction with the accompanying drawings. The components in the figures are not necessarily to scale and simply illustrate the principles of the systems, devices, and methods. For example, elements in the figures may be exaggerated in size to better aid in the understanding of the portrayed embodiments. The accompanying drawings illustrate only possible embodiments of the systems, devices, and methods and are therefore not to be considered limiting in scope.

(2) FIG. 1 depicts a microchip including edge interconnects or nodules;

(3) FIG. 2 depicts interconnecting two microchips on a substrate via edge interconnects or nodules on each substrate;

(4) FIG. 3 depicts difficulties in interconnecting two microchips of different thicknesses on a substrate, where the edge interconnects or nodules are at different heights from the surface of the substrate;

(5) FIG. 4 depicts interconnecting two microchips of different thicknesses on a substrate via edge interconnects or nodules on each substrate.

(6) FIG. 5 depicts interconnecting two microchips using multiple manipulators;

(7) FIG. 6A depicts two microchips aligned in three-dimensional space;

(8) FIG. 6B depicts the two microchips of FIG. 6A interconnected in three-dimensional space;

(9) FIG. 7 depicts four microchips interconnected or positioned to be interconnected together; and

(10) FIG. 8 is a flow diagram of a method for interconnecting an arbitrarily large array of microchips.

DETAILED DESCRIPTION OF THE INVENTION

(11) It is advantageous to define several terms before describing particular embodiments. It should be appreciated that the following definitions are used throughout this application.

Definitions

(12) Where the definition of terms departs from the commonly used meaning of the term, the definitions provided below are intended, unless specifically indicated otherwise.

(13) For the purposes of the present description, the term “direct electrical connection” refers to the direct contact between interconnect nodules or between an interconnect nodule and an electrical contact so that electrical conduction current may pass between them.

(14) For the purposes of the present description, the term “electronic device” refers to electronic circuitry and any device that includes electronic circuitry. Examples of electronic devices include, but are not limited to, microchips, package systems, transistors, printed circuit boards (PCBs), amplifiers, sensors, inductors, capacitors, electrical connectors into which microchips may be plugged, etc.

(15) For the purposes of the present description, the term “interposer” refers to any structure whose purpose is to extend or complete a conductive electrical connection between two electronic devices. In some embodiments, the conductive electrical connection between interconnect nodules or between an interconnect nodule and a contact may not be direct. For example, in some embodiments, a conductive material, such as solder, may electrically connect two interconnect nodules or an interconnect nodule with an electrical contact. Also, in some embodiments, connectors of various types may help conductively join interconnect nodules.

(16) For the purposes of the present description, the term “microchip” refers to any kind of chip having microfabricated or nanofabricated systems built thereon. Microchips include not only conventional integrated circuits but also Microelectromechanical Systems (MEMS) chips and other related technologies.

(17) For the purposes of the present description, the term “complementary nodules” refers to two microchips containing nodules arranged in a mirrored pattern to one another. In other words, two microchips with complementary nodules are capable of being aligned to form an electrical connection between the two microchips via the nodules.

DESCRIPTION

(18) Aspects of the system and methods are described below with reference to illustrative embodiments. The references to illustrative embodiments below are not made to limit the scope of the claimed subject matter. Instead, illustrative embodiments are used to aid in the description of various aspects of the systems and methods. The description, made by way of example and reference to illustrative reference, is not meant to being limiting with regards to any aspect of the claimed subject matter.

(19) Devices and methods described in this application are particularly well-adapted for use in joining microchips manufactured with solid edge-to-edge interconnects, such as Quilt Packaging® interconnect technology, and will be described in that context. However, it will become apparent that this description is not illustrative of the only utility of the described devices and methods.

(20) The assembly of advanced system-in-package (SiP) designs using innovative packaging and interconnect technology requires substantial innovation in assembly and handling tools and methods. Current approaches for assembling and packaging microchips are wholly unsuited for advanced SiP designs. Accordingly, there exists a long-felt but unaddressed need for improved apparatuses and methods for precisely and reliably assembling advanced SiP designs.

(21) FIG. 1 depicts a microchip 100 configured with solid edge-to-edge interconnects, such as those employed in microchips configured with Quilt Packaging® interconnect technology and described in U.S. Pat. Nos. 7,608,919 and 7,612,443 to Bernstein et al. which are incorporated herein by reference. “Quilt Packaging” is a U.S. registered trademark of Indiana Integrated Circuits, LLC, U.S. Registration No. 4214679.

(22) As shown in FIG. 1, nodules 102 made of metal or another conductive material are located along and extend from at least one edge 104 or surface 110 of microchip 100. These nodules 102 are used to electrically and mechanically connect microchips together, either through a direct electrical connection or via an interposer (such as solder). As shown here, nodules 102 are located near the top face 106 (or surface) of microchip 100. Generally, nodules 102 are either located contiguous to or a predetermined distance below top face 106 of microchip 100. The placement of nodules 102 may be standardized for a single microchip (so that all of the nodules are located the same distance below top face 106) or across different microchips to facilitate alignment of nodules 102 on different microchips. However, one of skill in the art will appreciate that nodules 102 may be placed at any point along the edge 104 of the microchip 100, so long as the two microchips to be joined have complementary nodules 102.

(23) Microchip 100 is depicted in face-up orientation, such that when microchip 100 is placed on a supporting surface 108, the face closest to the nodules 102 (top face 106) is exposed. Conversely, a microchip would be termed face-down if top face 106 (the face closest to the nodules 102) were in contact with supporting surface 108, such that top face 106 was not exposed. Placing two microchips 100 configured with complementary nodules 102 adjacent to one another, such that the nodules 102 of the first microchip 100 contact the nodules 102 of a second microchip 100, forms a direct electrical connection between the two microchips. Alternatively, the nodules 102 may be positioned such that they are close together but not in direct physical contact, allowing an indirect electrical connection between the two microchips through an interposer (such as solder).

(24) As described hereinafter, microchips may be joined together in a more permanent fashion to form a stable electrical and mechanical connection between them. An arbitrary number of microchips may be joined together to form an arbitrarily large array, allowing for electrical connections between each microchip and its neighbors. To facilitate the creation of electrical and mechanical connections between multiple microchips, in an embodiment, these nodules 102 are created with a coating of solder. This solder may further be used as an interposer to facilitate indirect electrical connections.

(25) Referring to FIG. 2, in one embodiment, a method is provided for connecting two microchips 200a, 200b. A manipulator 204 (such as a vacuum tool or a mechanical probe) places a first microchip 200a face-up on a substrate 206 and maneuvers microchip 200a into position. As used herein, the term “substrate” is a supporting surface or stage. Alternatively, first microchip 200a could be placed into position on a package, for example, to allow two microchips to be simultaneously joined to each other and then immediately sealed into the package. In this instance, the package could be placed on substrate 206 and secured into position prior to the microchip being placed on or in the package.

(26) Once first microchip 200a has been correctly positioned, it is secured in place. In an embodiment, first microchip 200a is secured in place by applying vacuum pressure via substrate 206. For example, holes may be included in substrate 206 through which vacuum may be applied to the back-side of first microchip 200a. The amount of vacuum applied through each hole or subset of holes may be individually controlled, allowing different amounts of vacuum to exist at different locations on substrate 206. Accordingly, a higher vacuum pressure could be applied to one microchip while a lower vacuum pressure is applied to a second microchip—preventing the first microchip from moving while requiring a predetermined amount of force to move the second microchip. For example, the necessity of using a predetermined amount of force to overcome the vacuum and move the second microchip would decrease the likelihood of the second microchip accidently moving. Alternatively, first microchip 200a may be held in place by manipulator 204 or another physical restraint, such as a clip, backstop or brace attached to the substrate 206.

(27) After first microchip 200a is secured in place, a second microchip 200b is then placed on substrate 206 by manipulator 204 and aligned with first microchip 200a in the y-axis. In an embodiment, second microchip 200b is lightly restrained against substrate 206 by applying vacuum through holes located in substrate 206, so as to make it easier to perform the necessary fine adjustments to properly position second microchip 200b. In another embodiment, physical features on substrate 206 (such as grooves, walls, etc.) are used to properly position second microchip 200b and prevent it from moving in the y-axis. Manipulator 204 then moves second microchip 200b along the x-axis until it is in contact with the first microchip. More specifically, second microchip 200b may be moved along any path until nodules 202b on second microchip 200b are in contact with nodules 202a on first microchip 200a. In an embodiment, lateral pressure is applied between the first and second microchips 200a, 200b (for example, by manipulator 204) along the x-axis.

(28) As improper alignment may result in some or all of nodules 202 failing to form electrical or mechanical connections, in an embodiment the alignment of two or more pairs of nodules 202a, 202b located at opposite edges of two microchips 200a, 200b are checked, for example, through the use of machine vision or electrical testing using a probe. As an example, if microchips 200a, 200b are slightly misaligned or if one of the microchips is skewed, a first pair of nodules 202 at one end of the set of nodules could be perfectly positioned for connection while the last pair of nodules (located at the opposite end of the chips) could be significantly misaligned. In an embodiment, larger nodules are created at each edge of the microchip to further facilitate proper x/y alignment.

(29) Referring again to FIG. 2, second microchip 200b is then held securely in place similarly to first microchip 200a. As will be apparent to one of skill in the art, multiple manipulators 204 could be used, for example, to secure or position both microchips 200a, 200b simultaneously or to enable microchips 200a, 200b to be held in place without the use of vacuum or another physical restraint on substrate 206.

(30) After the two microchips 200a, 200b have both been secured in place to substrate 206, microchips 200a, 200b are connected together, both electrically and mechanically. In one embodiment, microchips 200a, 200b are connected through a solder reflow process. Nodules 202a, 202b, located along the edges of microchips 200a, 200b that are to be joined together, are coated in solder or a similar material prior to positioning the two microchips 200a, 200b together. Then, when the two microchips 200a, 200b are positioned together, nodules 202a on first microchip 200a are placed in contact with nodules 202b on second microchip 200b. Localized heat (e.g., from a hot air reflow gun, an infrared reflow gun, a soldering iron, a light bulb, or another localized heat source) is then applied to nodules 202a, 202b to melt the solder, allowing the solder on nodules 202a to melt and merge with solder on nodules 202b, forming multiple continuous connections between microchips 200a, 200b at each pair of nodules 202a, 202b. The heat is then removed from nodules 202a, 202b, allowing the reflowed solder to cool and solidify into an unbroken electrical and mechanical connection between the two microchips 200a, 200b.

(31) Alternatively, heat can be applied to the entirety of both microchips 200a, 200b (e.g., by using heaters located in the substrate, heating the air surrounding microchips 200a, 200b, or another generalized heat source) to raise the temperature of both microchips 200a, 200b to some temperature T1 which is less than the melting point of the solder. A second, localized heat source is then used to raise the temperature of the solder on nodules 202a, 202b to a second temperature T2, which is at or above the reflow temperature of the solder. Among other advantages, this enables the solder to melt more quickly and avoids subjecting the entirety of both microchips 200a, 200b to high temperatures (such as T2), which could potentially damage microchips 200a, 200b. Additionally, a less intense localized heat source may be used to avoid damaging microchips 200a, 200b and to consume less power. In another embodiment, nodules 202a, 202b on microchips 200a, 200b are joined through a welding process, such as laser welding. Alternatively, melted solder or a conductive epoxy can be applied to nodules 202a, 202b to form direct or indirect connections between the microchips 200a, 200b.

(32) After microchips 200a, 200b have been connected together to form a multi-chip device, post-processing, such as packaging, may be performed. If microchips 200a, 200b were connected together inside a package, the multi-chip device can then be directly connected to the package through a process such as wire-bonding. Alternatively, the multi-chip device may be encapsulated or otherwise protected by the application of a protective material, such as an epoxy or polymer.

(33) Referring to FIG. 3, the difficulties inherent to connecting two microchips 300a, 300b of different thicknesses is shown. In order to form a reliable electrical connection, nodules 302a on first microchip 300a must be properly aligned with nodules 302b on second microchip 300b. To form a direct electrical connection, each pair of nodules should be in direct physical contact with one another. Alternatively, an indirect electrical connection can be formed through the use of an interposer, such as solder. This allows an electrical connection to be established even if the nodules are slightly misaligned. As shown in FIG. 3, when microchips of different thicknesses are to be connected together, it may be difficult or impossible to form a direct electrical connection between microchips 300a, 300b by placing them adjacent to one another in a face-up orientation, as nodules 302a, 302b will be located at different heights off substrate 304. Further, as depicted in FIG. 3, if the distance between the nodules 302a on the first microchip 300a and the nodules 302b on the second microchip 300b is great enough, it may be impossible to form a reliable electrical connection even with the use of an interposer.

(34) Referring to FIG. 4, a method of joining two or more microchips 400a, 400b of different heights to form a microchip unit is described. A first microchip 400a is placed face-down on a substrate 406 (e.g., a stage, package, or printed circuit board) by a manipulator 404 and maneuvered into position. The substrate 406 may be composed of a material to which solder will not adhere (e.g., a non-metallic compound) to avoid having the microchips 400a, 400b inadvertently connected to the substrate 406. Once it is properly positioned, first microchip 400a is secured in place. Manipulator 404 then places a second microchip 400b face-down on substrate 406, aligns the two microchips 400a, 400b, and moves second microchip 400b such that nodules 402b are aligned with nodules 402a on first microchip 400a. In an embodiment, lateral pressure is applied along the x-axis between the first and second microchips 400a, 400b (for example, by the manipulator 404). Second microchip 400b is then held securely in place similarly to first microchip 400a. As will be apparent to one of skill in the art, multiple manipulators 404 could be used, for example, to secure or position both microchips 400a, 400b simultaneously.

(35) As both microchips are located face-down, the nodules 402a, 402b are located the same distance above the substrate 406 regardless of whether the two microchips 400a, 400b are of equal thicknesses. This allows microchips manufactured from different materials (or wafers of varying thicknesses) to be joined, so long as the microchips have complementary nodules that are manufactured contiguous to or a predetermined distance below the top face of the respective microchip. As described above, modules 402a, 402b are then joined (e.g., by using solder reflow).

(36) Also or alternatively, substrate 406 may include a conductive segment or contact 410 positioned in alignment with nodules 402a, 402b when microchips 400a, 400b are positioned as shown in FIG. 4. In an embodiment, conductive segment or contact 410 may be connected to one or more other electronic devices of substrate 406 or disposed on substrate 406. In an embodiment, conductive segment or contact 410 may be a conductive trace or contact on substrate 406 which in an embodiment may be a printed circuit board. Once nodules 402a, 402b are located in alignment with conductive segment or contact 410 as shown in FIG. 4, nodules 402a, 402b and conductive segment or contact 410 are joined electrically in any suitable and/or desirable manner (e.g., via solder reflow). An advantage of nodules 402a, 402b in alignment with conductive segment or contact 410 is the facilitation of the visual inspection of nodules 402a, 402b and conductive segment or contact 410 after joining together, rework of a faulty joining together, and spacing between microchips 400a, 400b while simultaneously forming an electrical connection between nodules 400a, 400b and conductive segment or contact 410 thereby facilitating a flow of cooling fluid (air) between microchips 400a, 400b.

(37) Referring to FIG. 5, a method of joining two or more microchips 500a, 500b of different heights without using a stage or other surface is described. As shown in FIG. 5, a first manipulator 504a positions a first microchip 500a in space. First microchip 500a is then secured in place (e.g., by locking manipulator 504a in place). A second manipulator 504b positions a second microchip 500b in space. For example, second manipulator 504b will align the nodules 502a, 502b of the two microchips 500a, 500b along both the y- and z-axes. As will be clear to one of skill in the art, this allows for microchips of different thicknesses to be easily connected. Second manipulator 504b is then prevented from moving in the aligned axes. Second manipulator 504b then moves the second microchip 500b along the x-axis until nodules 502b on second microchip 500b contact nodules 502a on first microchip 500a. One or both of manipulators 504a, 504b then apply lateral pressure between microchips 500a, 500b along the x-axis. Second microchip 500b is then secured in space (e.g., by locking second manipulator 504b from moving). Microchips 500a, 500b are then joined, for example, via solder reflow.

(38) Referring to FIGS. 6A and 6B, a method of joining two or more microchips 600a, 600b into three-dimensional (3D) arrangements is described. A first microchip 600a is positioned on a substrate 606 using a manipulator 604 and subsequently is secured in place. The first microchip 600a is created with holes or sockets 602a located along its top face 608. In one embodiment, these holes are coated in solder. A second microchip 600b is then positioned above first microchip 600a by manipulator 604. Each of the nodules 602b along an edge 610 of second microchip 600b is aligned with respective holes or sockets 602a on first microchip 600a. As described above, merely aligning a single nodule-hole pair may cause an inadequate or non-existent connection between some nodules 602b and holes 602a if microchips 600b, 600a are misaligned or skewed, as other nodule-hole pairs may be misaligned. Accordingly, in an embodiment, two or more nodule-hole pairs located at opposite ends of second microchip 600b are checked to ensure proper alignment has been achieved.

(39) As shown in FIG. 6B, nodules 602b on second microchip 600b are then moved into alignment and contact holes or sockets 602a on first microchip 600a and pressure is applied between the two microchips 600a, 600b, for example by the manipulator 604 to press nodules 602b into holes 602a. The two microchips 600a, 600b are then joined, for example by using solder reflow. Additional microchips can then be connected to either the first or second microchip 600a, 600b in similar fashion. In an alternative embodiment, first microchip 600a could be held by a manipulator and positioned in space, without using a stage to support it. Second microchip 600b could then be aligned and moved into alignment and contact with first microchip 600a by a second manipulator. This process could be repeated for any number of microchips, thereby creating a three-dimensional array of interconnected microchips.

(40) Referring to FIGS. 7 and 8, a method of joining an arbitrary number of microchips is described. As shown in FIG. 7, four microchips 700a, 700b, 700c, 700d may be joined into a 2×2 array by first creating two pairs 702a, 702b of connected microchips—joined together in any manner described herein. Then, the two pairs 702a, 702b of microchips are joined together, in any manner described herein, to form a single array composed of four interconnected microchips 700a, 700b, 700c, 700d.

(41) As will be understood by one of skill in the art, an arbitrary number of microchips could be joined together in any manner described herein together in any manner described herein in similar fashion. For example, a system comprised of an odd number of microchips could be formed by first forming and connecting pairs of microchips and then joining a single unpaired microchip. Similarly, an arbitrary number of microchips of different shapes or sizes could be joined into an interconnected array using this technique. For example, nodules may be located along the interior edges of all microchips in the array, forming electrical and mechanical connections between all adjacent microchips and allowing each microchip to communicate directly with all adjacent microchips. Similarly, microchips may relay signals, so as to allow non-adjacent microchips in the array to communicate. Additional nodules could be formed along exterior edges, for example to allow additional microchips or other electrical devices to be connected to the array.

(42) FIG. 8 depicts a generalized process for creating an arbitrarily large array of interconnected microchips. As described above, in step 800, two microchips are joined (creating a pair of microchips). At step 802, a determination is made if additional microchips need to be added to the array. If no microchips need to be added, then the process ends at step 810. If more microchips need to be added, then a determination is made at step 804 whether there are two or more microchips to add. If so, then two microchips are joined into a pair at step 806 and are added to the array at step 808. The process then repeats by checking whether more microchips need to be added at step 802. Alternatively, if there is only a single microchip to add at step 804, then the single microchip is added at step 812 and the process ends at step 814.

(43) As will be clear to one of ordinary skill in the art, the process described in FIG. 8 creates an array of microchips that is two microchips wide and an unlimited number of microchips long. Alternatively, the process may be modified to create an array of arbitrary size. For example, a 8×8 array of sixty-four square microchips could be created by first creating thirty-two pairs of microchips, as described above. Each pair (or 2×1 array) is then treated as a single microchip, and paired again to create sixteen 2×2 arrays. The process repeats, successively pairing microchips to create eight 4×2 arrays, four 4×4 arrays, two 8×4 arrays, and finally a single 8×8 array. A similar form of this process could be used to join microchips of any shape into an array of arbitrary size.

(44) What has been described above includes examples of aspects of the claimed subject matter. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the claimed subject matter, but one of ordinary skill in the art may recognize that many further combinations and permutations of the disclosed subject matter are possible. Accordingly, the disclosed subject matter is intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the terms “includes”, “has”, “having”, or variations in form thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.