RU2374793C2 - Contact assembly on opposite contacts with capillary connection element, and manufacturing method thereof - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention refers to contact assemblies on opposite contacts by means of which equipment is assembled from naked components, including erection of large-scale integration (LSI) chips in housings, as well as consisting of multichip modules. There proposed is contact assembly on opposite contacts, which consists at least of two flat contacts connected to each other electrically and mechanically with a connection element made from conducting material in the form of a connection strap. At that, each of the above contacts is located on flat surface of one of two coplanar carriers; contacts are directed towards each other relative to common axis which is orthogonal relative to coplanar carriers and which passes through centres of contacts, and gap between coplanar carriers of opposite contacts and around connection element is filled with dielectric material; at that, connection element is made in the form of a capillary with end flanges, which is filled, either partially or fully, with conducting bonding material drawn in the above capillary from opposite contacts on which it has been located before under influence of capillary forces which appear when conducting bonding material is changed to liquid state at process effect when assembling contact assembly so that mechanically resistant conducting connection is formed between opposite contacts after process effect is stopped; at that, the above capillary is made in the form of a hole the inner side of which is covered with the above wet conducting bonding material in plane parallel plate made from dielectric material, which is a capillary connection element carrier and is located in the gap between coplanar carriers of opposite contacts; at that, longitudinal capillary axis passes through centres of the above opposite contacts in orthogonal direction relative to surfaces of the above carriers of opposite contacts, and the above end flanges of capillary, which are located on surfaces of the above plane parallel carrier of capillary connection element, are end-to-end connected to opposite contacts and mechanically and electrically connected to them by means of a thin layer of the above conducting bonding material.

EFFECT: providing increased reliability of devices owing to increasing strength characteristics of contact assembly, and resistance to thermal cycles.

35 cl, 35 dwg, 1 tbl

Description

Technical field

The invention relates to electronic equipment - the design and manufacture of one-piece soldered joints, widely used in the manufacture of equipment based on microelectronics and semiconductor devices, and more particularly, to contact nodes on the oncoming contacts, through which the equipment is assembled from unpacked components, including the installation of crystals LSI (chips) in the housing, as well as in multi-chip modules (MKM).

State of the art

The development trend in this area of microelectronic technology is the search for physical and structural-technological principles that would make it possible to obtain contact nodes that remove the current obstacles associated with the formation of a large number (several thousand) of identical and reliable contact nodes connecting contacts on LSI crystals either with wiring conductors to external contacts of the LSI enclosure, or with conductors from different layers of a multilayer switching structure cheers MKM.

Thus, the problems of forming a large number of identical contact nodes are especially relevant in such areas of assembly as:

- installation of LSI crystals in the housing;

- installation of LSI crystals as a part of multi-chip modules (MKM - an electronic assembly of frameless components - LSI crystals).

Modern LSI crystals, as components for assembly, differ:

- a large area of crystals (> 1 cm ² );

- a large number of contact pads (~ 1 thousand pieces);

- the location of the pads either on the periphery of the crystal (for assembly by welding method - Wire Bond assembly technology), or in the form of a matrix over the entire area of the crystal (for assembly by soldering through protrusions from solder on the contact pads - Flip-Khir - flip chip technology assembly).

Certain prospects were associated with the technology of the contact nodes, in which the contacts were connected by extended connecting elements (SE) in the form of beam FE (A. Mazur et al. Welding and soldering processes in the manufacture of semiconductor devices. - M., Radio and communications, 1991 , p. 38-39), pre-formed (by group technological processes) on a thin polyimide (LI) film, in the form of metallized tracks - from contacts on a chip to response contacts on a switching substrate. The ends of the mentioned tracks are designed so that they can be connected by welding at one end to the corresponding contact on the chip, and the other to the contact on the substrate (such a PI structure is called a “spider”). After the tracks are connected to the contacts and the auxiliary fragments are removed, the pairs of contacts turn out to be connected by parallel conductors (beam form - hence the name: beam FE) attached to the surface of the PI structure. Those. in contrast to the classical method of assembly by welding with wires, SCs in the “spider” cannot close each other. In addition, all spider FEs of future KUs are formed before assembly in a group process in advance, and are not wound (from a coil), are measured and formed sequentially, one after the other, as occurs during conventional assembly by welding.

Nevertheless, the technology of mounting crystals using PI spiders, representing an option for the development of a method of assembling by welding wires (Wire Bond), inherits the main disadvantages of this method:

- all contacts on the chip should be located at the edges of the chip (this limits the number of input / output contacts on the chip by linear growth from the size of the chip);

- the sequential (non-group) nature of the assembly by welding (this determines the duration of the assembly process, i.e., the probability of failure of the assembly machine and% reject);

- the possibility of latent defect formation in the chip during welding exposure (this determines the probability of failure in operation, i.e. the operational reliability of equipment containing such chips).

To overcome these shortcomings, IBM in the early 60s of the XX century proposed a method of forming and arranging a contact node (KU) for flip-chip technology for assembling (mounting) an IC chip (chip) on a switching substrate.

The KU flip chip consists of two flat contacts of the same shape and area, one of which is placed on the working surface of the IC chip facing the surface of the switching substrate, and the other contact, of the two flat contacts mentioned, is placed on the surface of the switching substrate facing the working surface a crystal, and the aforementioned surfaces of the crystal and the switching substrate are plane parallel, the axes and orthogonal projections of the contours of both contacts are aligned, and the contacts themselves are rigidly connected to each other by a jumper d from the solder in such a way that between the mentioned surfaces of the crystal and the switching substrate, after the formation of all contact nodes, a plane-parallel gap is formed, which, as a rule, is filled with a hydrophobic elastic electrical insulating material (underfill), designed to compensate for significant thermomechanical stresses between the crystal and the switching substrate with technological influences and during operation.

Thus, in this assembly method, the IC chip (chip) is turned (turned) by the working surface to the switching substrate, for which the method itself is called Fllip-Chip (flip chip - inverted chip).

A flip-chip contact node connecting two oncoming contacts can be classified as a “contact node on oncoming contacts" (KU VK).

The components for the flip chip assembly technology (Electronic Assembly in the Next Millennium collection, Innovation in Surface Mount Tecnology article, translation and adaptation by A. Kalmykov) have deservedly won their place in the assembly market due to their obvious advantages, which include:

- saving space on the printed circuit board;

- low height and light weight;

- reduction in the cost of materials;

- reducing the length of the joints, which provides better electrical parameters;

- fewer connections, which reduces the number of potential failures and provides a more efficient distribution of thermal energy.

But, like everyone else, this popular technology, in recent years symbolizing the cutting-edge trends of surface mount technology (SMT), has its drawbacks:

- the high cost of technology for the formation of spherical protrusions (Bumps = bumps) on the contact pads of the crystal;

- extremely dense wiring of the board under the seat for the flip chip chip LSI, which leads to increased costs for the switching board (substrate);

- a large amount of work of technologists on the optimal choice of fluxing substances and adhesives, depending on the type of flip chip component, substrate and soldering process;

- Difficulties in monitoring the quality of the process and the results of soldering flip chip components, as well as repair.

In addition, the issue of stability of the yield level of crystals suitable for bumping has not yet been resolved. The assembly cycle time using the flip chip technology can be quite long due to the stages of applying special materials and their curing processes. Particular attention should be paid to the distribution of thermal energy to ensure high reliability of the assembly.

The infrastructure supporting the flip-chip technology for the electronic industry is still not as developed as other standard technologies.

You can also highlight the following features in the development of flip chip technology:

- 60% of the total global consumption of flip chips falls on chip crystals with a low number of input / output contacts (channels) used in the manufacture of electronic watches and automotive electronics;

- followed by chips with an average number of input / output channels used in display drivers, PCMCIA format modules, as well as in larger computer products;

- and, finally, microcircuits with the number of input / output channels from 2000 and higher, which use crystals with a high degree of integration and reliability, usually mounted on ceramic substrates.

The growth in the use of flip-chip components in portable communications is expected, which is likely to be relevant for Russian electronics in the next few years, as well as in computer products of high complexity.

The use of flip chips in products with a high degree of integration and reliability is highly dependent on the development of a reliable and repeatable technology for their production.

A favorable circumstance in the use of flip-chip technology is the great constructive and technological experience gained in the development and creation of the above-mentioned contact nodes.

However, the contact nodes formed using this technology do not allow direct visual and electrical control of the process and the assembly of the contact node due to the fact that the crystal facing its contact pads to the substrate closes all the combined contact pads on the substrate. In addition, in such structures there is no natural way out of the gap between the substrate and the crystal for technological waste, which can lead to degradation phenomena in the crystal during operation and reduce the reliability of the crystal.

Those. The direct transfer of this experience to the field of microelectronics cannot be done automatically, without taking into account the special requirements for contact nodes with the specifics of assembly processes in modern microelectronics.

Known microelectronic node containing:

- a chip of a semiconductor chip having upper and lower flat surfaces directed in opposite directions, said chip having output contacts located at the periphery of said bottom surface;

- a switching substrate having on the surface facing the crystal of said microcircuit, electrically conductive metallized tracks and output contacts, said output contacts being connected to said metallized tracks, placed movably relative to said microcircuit;

- an elastic layer located between said substrate and said lower surface of said microcircuit to facilitate the movement of said metallized tracks, as well as between said electrodes and said microcircuit, wherein said malleable layer consists of a material with a low modulus providing independent movement of said electrodes, as in a direction parallel to said rear surface of said microcircuit, and in a direction perpendicular to the rear surface of said ikroskhemy;

- wire rails connected to said microcircuit contacts on the front surface of said microcircuit, said wire rails extending downward along said edges of said microcircuit and connected to flexible terminal parts of a substrate adapted to control the impedance of said flexible terminal parts located on it;

- said substrate includes a polymeric dielectric material made in the form of a flexible sheet material selected from the group consisting of polyimide, fluoropolymer, thermoplastic polymer and elastomers, providing free movement of electrodes relative to the microcircuit, said substrate also including an electrically conductive layer adapted to facilitate electrical insulation of the terminals of the electrodes from the microcircuit and to provide better control of the impedances of the said terminal parts;

- said microcircuit contacts define a first center-to-center distance between adjacent microcircuit contacts, and said electrodes define a second center-to-center distance between adjacent electrodes, said second center-to-center distance being larger than said first center-to-center distance;

- said substrate has an upper surface facing the microcircuit, and a lower surface facing away from the microcircuit, and said flexible lead parts and electrodes can be located both on said upper surface of said substrate and on said lower surface of said substrate, wherein the substrate includes holes passing through it from said upper surface to said lower surface, wherein the electrodes are opened through said holes and attached to them by a binder material;

a dielectric sealant covering at least a portion of said substrate and at least a portion of said edges and said front and rear surfaces, as well as at least a portion of said wire rails and at least a portion of said edges and said front surface of said microcircuit, said sealant being pliable;

- a heat-conducting layer associated with said front surface of said microcircuit (US patent No. 5852326, IPC H01L 23/48, 23/52, publ. 1998).

Known contact node containing at least two metallized contacts associated with current paths located on the surfaces of the switching layers, made on the basis of a dielectric material, combined with each other and interconnected by an electrically and mechanically electrically conductive binder material, representing a joint between contact made in the form of a metallized flat contact pad associated with current-carrying paths on the surface of the underlying switching layer and a reciprocal contact docked with it, made in the form of a metallized hole in the layer of dielectric material, the lower edge of the metallized hole facing a metallized flat contact area on the surface of the underlying switching layer, and its upper edge connected with current paths on the upper surface of the overlying switching layer . In this case, the metallized hole can be made in the form of either a cylinder or a truncated cone, and the metallized contact pad is flat, and a protrusion is formed in the center of the metallized contact pad responding to the metallized hole and is made of an electrically conductive hole in the form cylinder, cone or ball. In addition, the contact corresponding to the metallized hole can be made in the form of a rod fixed in the underlying switching layer, orthogonal to its surface, and inserted into the aforementioned metallized hole (international application WO 00/35257 A1, published in accordance with the patent cooperation agreement) .

In this contact node, it was possible to largely eliminate the above-mentioned disadvantages inherent in the known designs of contact nodes. However, the ever-increasing requirements for microminiaturization, on the one hand, and the technical characteristics of MKM, on the other hand, make the task of further improving the design of the contact assembly, which allows us to satisfy the constantly growing requirements, constantly relevant.

At the same time, the well-known KU has a pronounced asymmetry with respect to the contacts in the KU: one contact is flat (for example, on a chip or a printed circuit board made of fiberglass), and the second contact is in the form of a metallized hole in the film switching structure. And although the need and relevance of such an “asymmetric” CM is especially significant when creating close-packed equipment based on single and multi-layer flexible film switching chip carriers as part of multi-chip modules (MCMs), when assembling MCMs, the tasks of efficient pairing of oncoming contacts (VC) pairs often arise, placed on oncoming flat coplanar rigid media. A striking example of solving this problem (KU on VK) is a KU flip chip and flip chip technology for mounting an IC chip (a rigid and brittle wafer made of Si or another single-crystal semiconductor), for example, on a hard switching substrate made of multilayer ceramic.

A contact assembly is also known, one of the possible embodiments of which is shown in FIG. 5 of the patent, containing at least two metallized contacts (16, 27) associated with conductive tracks placed on the surface of the connecting layers made on the basis of a dielectric material and mutually aligned and interconnected by an electrically and mechanically conductive binder material (26), while it is made in the form of an intersection between a contact made in the form of a metallized contact pad (27), connected with conductive paths on the surface of the connecting layer, and the corresponding contact connected to this contact pad and made in the form of a metallized hole (15) in the overlying connecting layer, the lower edge of the metallized hole facing the metallized contact area on the surface of the underlying contact layer, and the upper edge this hole is connected with the conductive tracks (21) on the upper surface of the overlying connecting layer, while the metallized hole has the shape of a cyl Indra, the upper edge of the metallized hole associated with the conductive paths on the surface of the connecting layer forms a metallized rim around the periphery of the edge, the metallized contact area is flat, the upper and lower edges of the metallized hole have a bevel.

Another possible embodiment of said contact assembly in accordance with this invention is shown in FIG. 3 of the patent, wherein the contact assembly comprises: a first connecting layer (41) having a conductive track on its surface; a second connecting layer (42) deposited adjacent to the first connecting layer having a conductive track on its surface; and a metallized hole (43) through the first connecting layer connected by its inner surface to the conductive track of the first connecting layer; and a metallized contact pad provided on the surface of the second connecting layer and connected to the conductive track of the second connecting layer, wherein the conductive bonding material (45) is deposited in the metallized hole for contacting the inner surface of the metallized hole and the metallized contact pad to form a connection between the first and the second connecting layers, the metallized hole has the shape of a cylinder (US patent No. 6100475).

This patent discloses and protects solutions aimed at ensuring high-quality installation of a printed circuit board with BGA outputs (for example, ICs in a housing with BGA outputs) on a circuit board by soldering (BGA / Ball Grid Array is a matrix array of protrusions made from solder, usually in the form of ball bumps).

It is known from the prior art that arrays of ball-type BGA contacts (bumps) in BGA devices are characterized by the following main parameters:

- dimensions (height) of bumps (-100 microns);

- “step” of bumps (> 200 microns) with their matrix arrangement in a given grid;

- dimensions of the matrix area with bumps (usually <50x50 mm);

- composition of bump materials (usually Pb-Sn, Sn-Bi and Pb-Ag);

- melting temperature of bumps: low temperature (<180 ° С) and high temperature (> 220 ° С), etc.

It is also known that the main problems of mounting printed circuit boards with BGA-outputs that have not been solved to date are:

- ensuring the accuracy of alignment of the BGA-protrusions with the reciprocal flat contacts;

- prevention of "slipping" of the BGA-protrusions from the reciprocal flat contacts in the process of combining, fixing and soldering;

- elimination of “distortions” in the coplanarity of mounted boards when combining contacts, fixing and soldering;

- maintaining a uniform fixed gap between the boards during the soldering process, when the BGA-protrusions become liquid;

- elimination of the “spreading” of the BGA protrusions in the molten state, which leads to short circuits between the BGA outputs, etc., hidden from the visual control.

This patent is aimed at solving the above problems of the BGA assembly. An original solution is proposed for preliminary fixation of the printed circuit board, with BGA-contacts located on the lower side at a predetermined distance from the surface of another circuit board (mounting base), which carries on its upper side an array of mating flat contacts.

Fixing is achieved using special protrusions-bumps from high-temperature ~ 220 ° С solder, pre-formed on the response metallized sites on the board, for example, carrying BGA-contacts, and located on the periphery or inside the array of BGA-contacts.

At the first stage of assembly, strict fixation of the protrusions-bumps from the high-temperature solder relative to the reciprocal flat contacts on the lower board is provided. In this case, the gap between the boards is strictly maintained before the main soldering, carried out at a temperature of ~ 180 ° C of the array of BGA bumps. High temperature> 220 ° С bridges from solder based on peripheral holes:

- do not allow BGA bumps to “move out” of the reciprocal flat contacts during the main soldering process at a temperature of <180 ° C;

- provide a strict gap between the connected boards;

- protect low-temperature bumps from “spreading” and short circuiting with each other with low-temperature <180 ° С soldering.

The main purpose of the “flat contact soldered to a metallized hole” assemblies protected and disclosed in this patent is to pre-fix two boards with respect to each other by high-temperature jumpers to ensure the quality of the subsequent main soldering of an array of “bump-flat contact” pairs of contacts at low temperature < 180 ° C soldering.

The present invention is not aimed at providing a gap between the soldered boards, but rather, at providing a “gapless” connection of a flat contact (for example, on an IC chip) with a return contact in the form of a metallized hole (for example, in a flexible switching carrier of an IC chip) according to the principle “ soldering a flat bottom to the shell. "

A contact assembly is also known, one of the embodiments of which is shown in FIG. 2 of the patent, comprising at least two metallized contacts connected to conductive tracks placed on the surface of the connecting layers made on the basis of a dielectric material and mutually aligned and interconnected electrically and a mechanically conductive binder material (13), while it is made in the form of an intersection between a contact made in the form of a metallized contact pad (31) associated with a conductive paths on the surface of the connecting layer, and the corresponding contact connected to this contact pad and made in the form of a metallized hole (23) in the overlying connecting layer, the lower edge of the metallized hole facing the metallized contact area on the surface of the underlying contact layer, and the upper edge of this hole connected with the conductive tracks (24) on the upper surface of the overlying connecting layer, while the metallized hole has the shape of a truncated cone moreover, the lower base of the truncated cones is facing the contact area on the surface of the underlying connecting layer, and the upper base of the truncated cones is connected with the conductive tracks on the upper surface of the overlying connecting layer, the upper edge of the metallized hole connected with the conductive tracks on the surface of the connecting layer forms a metallized rim along the periphery of the edge, an integrated circuit chip (41), oriented by its metallized contact pads to existing metallized holes in the overlying connecting layer, is used as a connecting layer with metallized contact pads relative to the metallized holes in the overlying connecting layer, the metallized contact pad is flat; further comprising a protrusion (31) interacting with a corresponding metallized hole formed in the center of the metallized contact pad relative to the metallized hole, the protrusion has the shape of a sphere, the upper and lower edges of the metallized hole have a bevel.

Another possible embodiment of the invention is shown in FIG. 2 of the patent, wherein the contact assembly comprises: a first connecting layer (21) having a conductive track on its surface; a second connecting layer (30) deposited adjacent to the first connecting layer having a conductive track on its surface; and a metallized hole (23) through the first connecting layer connected by its inner surface to the conductive track of the first connecting layer; and a metallized contact pad (31) provided on the surface of the second connecting layer and connected to the conductive track of the second connecting layer, wherein the conductive bonding material (13) is deposited in the metallized hole to contact the inner surface of the metallized hole and the metallized contact pad to form a connection between the first and second connecting layers, the metallized contact pad has a metallized protrusion (11) in the form of a sphere in wire suitable binder material (US patent No. 6087597).

The technical solution protected in this patent, as well as the technical solution protected in the above US patent, is aimed at solving the problems of mounting boards with BGA-outputs on a carrier board with flat contact contacts.

The patent discloses a solution to the same problem: fixing a strict gap between the boards during the assembly process, as in the aforementioned US patent, but only in a different way.

The patent notes that a solid spherical core inserted between a flat contact area on the bottom plate and a conical shaped metallized hole tapering upward in the upper plate partially enters the said metallized hole, abutting against the conical surface of the metallized hole.

Such a constructive solution is achieved by fixing the gap between the upper and lower boards when they are soldered by solder previously placed in a metallized hole and on the surface of a solid spherical core.

Using protrusions of various shapes (spherical, conical, cylindrical), the authors facilitate the alignment of the flat contact area of the lower board, on which the protrusion is preliminarily placed, with the metallic response hole in the upper plate, into which the protrusion enters as a guiding element, without abutting against any obstacles and without interfering with the upper board, press firmly against the lower bearing surface.

The invention in accordance with the aforementioned patent is directed to:

- providing solder columns (bumps) of the same height;

- elimination of compression of bumps during soldering (in order to ensure and fix the gap between the boards);

- increase the strength of bumps.

As noted above, the claimed group of inventions is not aimed at providing a gap between the soldered boards, but rather, at providing a “gapless” connection of a flat contact (for example, on an IC chip) with a return contact in the form of a metallized hole (for example, in a flexible switching carrier of the crystal IP) on the principle of "soldering a flat bottom to the shell", which is not achieved in this patent.

The closest in technical essence to the claimed invention, in terms of the device, and the achieved technical result when using it, is a contact node in which the connection of the crystal contacts and the switching substrate is carried out by controlled pressing of the inverted chip to the switching substrate (method C4 = Controlled Collapse Chip Connection) , with the formation of the contact node (for each pair of oncoming contacts), consisting of two flat contacts, one of which is located on the IC chip, the inverted contact to the switching substrate, it has a protrusion from the solder, which acts as a connecting element, by means of which the contact is connected to the counter-contact on the said switching substrate with the solder deposited on the said contact, and after heating the solder protrusion and solder to the melting temperature, with metered pressure inverted crystal to the switching substrate, between the said contacts a mechanically strong electrical connection of the said counter contacts is formed. The gap between the inverted crystal and the switching substrate, after soldering the bumps, is filled with an elastic hydrophobic composition, which serves to unload thermomechanical stresses during technological influences and during operation (Microelectronics Packaging Handbook, Part II (Semiconductor Packaging), Second Edition, Edited by: Rao R. Tummala, Eugene J. Rymaszewski, Alan G. Klopfenstein, p. II-136 - II-144, by Kluwer Academic Publishers, 1999).

The C4 assembly method is the development of flip-chip technology aimed at reducing the likelihood of a circuit between adjacent bumps during soldering by controlled pressing of the chip to the substrate (to the disadvantages of the flip chip discussed above, you should add the possibility of uncontrolled closure of neighboring CE bumps - 80 -100-micron gap between the chip and the substrate during the soldering process).

Analysis of the advantages and disadvantages of the flip chip (C4) KU and flip chip (C4) assembly technologies led to the technical solution for this application in the form of a "symmetric" KU on VC type flip chip (C4), but with SC not in the form of bumps , and in the form of capillary SC (SSC).

This solution, like beam FEs fixed on the spider PI surface described above, eliminates the possibility of an uncontrolled short circuit between the SSCs in neighboring CCs on the VC. In addition, the technical solution for this application, while retaining the main advantages of the flip chip, multiplies them, as well as stops the existing disadvantages.

Disclosure of invention

The problem to which the claimed group of inventions is directed is to create such a contact node, the use of which in microelectronic equipment will eliminate the above-mentioned disadvantages inherent in existing and used contact nodes, both when assembling multilayer switching structures and when mounting crystals on mounting switching structures , i.e. contact node for mounting LSI crystals as part of multi-chip modules and when assembling LSI crystals in enclosures.

The technical result due to the use of the contact node in oncoming contacts with the capillary connecting element during the assembly of microelectronic equipment is to provide increased reliability of the devices by increasing the strength characteristics of the contact node due to a set of design features of the capillary connecting element in an elastic medium of a durable dielectric, as well as high uniformity contact nodes made in accordance with the present invention when groups new assembly, due to the capillary’s ability to “compensate” for an overdose of solder, as well as to resistance to thermal cycles, which is due to the elasticity and strength of the film dielectric, which is the carrier of capillary connecting elements, which is especially effective in structures like “silicon on silicon”. In addition, it ensures high manufacturability and efficiency of the assembly due to the capillary effect used in this technology, which can significantly increase the percentage of yield during assembly, as well as reduce the complexity and cost of preparatory operations, because eliminates the need for forming at the contacts of LSI crystals precision spherical bumps with characteristic sizes of 80-100 microns. In addition, after mounting the IC chip on the switching substrate, the “critical” operation of “pumping” into the 80-100-micron gap between the crystal and the substrate of a viscous elastic composition, which serves to compensate for stress loads in the crystal-substrate structure, during technological and operational thermomechanical influences, due to the difference in thermomechanical deformations of the said crystal-substrate structure.

The task underlying the claimed group of inventions, with the achievement of the aforementioned technical result in the process of its use in the part of the contact node, is solved by the fact that in the known contact node on the oncoming contacts, consisting of at least two flat contacts electrically connected and a mechanically connecting element made in the form of a jumper of electrically conductive material, wherein each of said contacts is placed on the flat surface of one of the two coplanar carriers, con the acts are oriented towards each other and aligned with each other relative to the common axis orthogonal to the coplanar carriers and passing through the contact centers, and the gap between the coplanar carriers of the oncoming contacts and around the connecting element is filled with dielectric material, in accordance with the invention, the connecting element of the contact node is made in the form of a capillary , with end flanges, filled with partially or fully electrically conductive binder material, drawn into the capillary from the opposite cts, on which it was previously placed, under the action of capillary forces arising from the transition of the binder of the electrically conductive material to the liquid state during the technological action during the assembly of the contact assembly, with the formation, after the termination of the technological action, of a mechanically stable electrically conductive connection between the oncoming contacts, the capillary is made in the form of a hole, the inner surface of which is covered with a wettable electrically conductive binder material, in a plane an allelic plate made of a dielectric material that is a carrier of a capillary connecting element and is located in the gap between the said coplanar counter contact carriers, the longitudinal axis of the capillary connecting element passing through the centers of the counter contacts, orthogonal to the surfaces of the coplanar counter contacts, and the said end flanges of the capillary connecting element located on the surfaces of said plane-parallel carrier capillary the first coupling element, are aligned end to end with the mating contacts and are connected mechanically and electrically to them with a thin layer of said electroconductive bonding material;

- as well as the fact that said electrically conductive binder material is made of solder, and said technological impact is thermal;

- as well as the fact that said electrically conductive binder material is gel-like and wetts the inner surface of the capillary connecting element, its flanges and counter contacts both during and after the termination of thermal and other influences;

- as well as the fact that the aforementioned electrically conductive binder material, previously before the assembly of the contact nodes, is placed inside the capillary hole;

- as well as the fact that the said counter contacts are offset relative to each other in the planes of their carriers, and the longitudinal axis of the capillary connecting element passing through the centers of the contacts is inclined at an angle α <90 ° to the surfaces carrying these contacts;

- as well as the fact that the capillary hole of the connecting element can be made cylindrical;

- as well as the fact that the capillary connecting element can be made in the form of a truncated cone, the smaller bell of the capillary connected to one oncoming contact, and the larger bell of the capillary connected to another oncoming contact;

- as well as the fact that the said counter contacts are offset relative to each other in the planes of their carriers, and the longitudinal axis of the capillary connecting element, made in the form of a truncated cone, passing through the centers of the contacts, is inclined to the planes carrying these contacts at an angle β <90 °;

- as well as the fact that the capillary connecting element is multi-channel;

- and also the fact that the capillary connecting element is a porous structure permeable to an electrically conductive binder material in the process of technological impact during the assembly of the contact node;

- as well as the fact that the inner surface of the capillary connecting element is made in the form of a surface of revolution relative to the longitudinal axis of the capillary;

- and also the fact that the inner surface of the capillary connecting element is made in such a way that the sections in the plane orthogonal to the longitudinal axis of the capillary are either polygons or smooth closed curves, for example ellipses;

- as well as the fact that on the surfaces of the oncoming contacts technological lugs are made with a bonding electrically conductive material deposited on them, while the mentioned technological projections of the contact node enter the capillary partially or completely from its two sides, providing mutual self-alignment of the said oncoming contacts and the capillary connecting element during the assembly of the contact node;

- as well as the fact that the technological protrusion, at least on one of the oncoming contacts of the said contact node, is made in the form of a spherical protrusion of a binder of electrically conductive material, partially or completely placed in the capillary during alignment during assembly of the contact node;

- as well as the fact that both said counter contacts have identical technological protrusions in size and shape;

- as well as the fact that both of the said counter contacts have technological protrusions of different sizes and shapes, and the sockets of the capillary connecting element associated with them are made of various sizes and shapes and are complementary to the corresponding protrusions of the counter contacts;

- as well as the fact that said plane-parallel carrier of the capillary connecting element is made in the form of a film of an elastic material, for example, polyimide;

- as well as the fact that around the capillary connecting element made in the aforementioned plane-parallel carrier of dielectric material, there are holes in this carrier filled with an adhesive composition for bonding the coplanar contact carriers in places free from contacts;

- as well as the fact that said plane-parallel carrier of dielectric material in which capillary connecting elements are formed is made in the form of a rigid plate having thermomechanical characteristics identical to the thermomechanical characteristics of oncoming contact carriers;

- as well as the fact that the carrier of capillary connecting elements is made of either glass or oxidized silicon;

- as well as the fact that the carriers of capillary connecting elements and oncoming contacts are made of the same material;

- as well as the fact that one or both of the aforementioned bearing surfaces with counter contacts are made of either silicon or gallium arsenide or other semiconductor material, which, in addition to counter contacts, have active and / or passive components and current paths on their surfaces made according to planar technologies of microelectronics;

- as well as the fact that one of the contact carriers is made in the form of an IC case with BGA-outputs, and the carrier with reciprocal counter contacts is made in the form of a printed circuit board for surface mounting (SMT) of components, and the case with BGA-outputs interacts with the SMT-board through an array of capillary connecting elements made in a film dielectric;

- and also the fact that both carriers of the oncoming contacts are the same IC housings with BGA-terminals, which interact with each other through an array of capillary connecting elements made in a film dielectric;

- as well as the fact that one contact carrier is an IC case with BGA-outputs, and the oncoming contact carrier consists of several smaller BGA-cases, moreover, the contour of their total area should fit into the area contour of the largest on-board BGA-case, and the interaction all BGA-housings should be implemented through a common array of capillary connectors made in a film dielectric;

- as well as the fact that on the surfaces of the plane-parallel carrier of capillary connecting elements there are conductive tracks connecting at least two capillary connecting elements;

- as well as the fact that on the surfaces of the aforementioned plane-parallel carrier of the capillary connecting element there are power buses and earth buses;

- and also the fact that the carrier of capillary connecting elements is made in the form of a plane-parallel plate of electrically conductive material coated with a thin layer of insulating material, including the inner surfaces of the holes, and the capillary connecting elements, as well as active and / or passive components, conducting tracks, are made on top of the above a thin layer of insulating material;

- as well as the fact that the conductive base of the carrier of capillary connecting elements is made of either copper or aluminum;

- and also the fact that the conductive base of the carrier of capillary connecting elements, made of either copper or aluminum, is used as a ground bus;

- as well as the fact that the said carriers of the oncoming contacts, as well as the carrier of the capillary connecting elements placed between the said carriers of the oncoming contacts, are made of various materials having the same thermomechanical characteristics.

A known method of manufacturing contact nodes in the process of mounting integrated circuits in housings with ball leads from solder made in a given coordinate grid on the contacts of the lower surface of the housing (BGA = Boll Grid Array), on a switching printed circuit board, including:

- application of solder paste to the contact pads of the switching printed circuit board, reciprocal to the ball leads of the IP housing;

- the combination of the ball leads of the housing with the response contacts of the switching printed circuit board;

- heating the soldering region to the melting temperature of the solder paste, as a result of which contact nodes are formed in which the ball contacts of the housing and the contact contacts of the switching printed circuit board are electrically and mechanically connected, i.e. the ball leads become connecting elements in the contact nodes, consisting of pairs of counter contacts on the bottom of the IC housing and the mounting surface of the circuit printed circuit board (Microelectronics Packaging Handbook, Part II (Semiconductor Packaging), Second Edition, Edited by: Rao R. Tummala, Eugene J. Rymaszewski, Alan G. Klopfenstein, p. II-93 - II-96, by Kluwer Academic Publishers, 1999).

This method has the following main disadvantages:

- Difficulties in ensuring the uniformity of ball conclusions;

- difficulties with removing by-products of soldering from the narrow gap between the housing and the switching printed circuit board;

- difficulties in keeping the solder balls from spreading from spreading in the molten state during soldering with the formation of short circuits between adjacent terminals;

- difficulties in controlling the process and soldering results in the narrow gap between the housing and the switching printed circuit board.

To control the results of mounting a BGA-case with a large number of ball contacts on a switching printed circuit board, complex and expensive methods of optical and x-ray control are used.

Closest to the claimed group of inventions in terms of the method of manufacturing the contact node, in technical essence and the achieved result in the process of its use, is the method of "flip chip" ("inverted crystal") of the manufacture of contact nodes in the process of mounting of open-circuit IC crystals on a switching substrate, including:

- application of thin-film metallization and solder layers to the contacts of the IC chip;

- manufacture on the tin-plated contacts of the crystal of mounting protrusions (bumps) from solder - blanks of connecting elements, from which, in the process of soldering, the above-mentioned connecting elements are formed between the oncoming contacts;

- tinning with solder of the reciprocal contacts located on the switching substrate;

- combining the aforementioned bumped contacts placed on the chip with counter-contacts on the switching substrate until they come into contact with fixing the alignment for the soldering time;

- heating of the contact zone to the melting point of the solder;

- lowering the temperature in the soldering zone until the curing of said solder, as a result of which contact nodes with connecting elements from solder are formed, providing electrical and mechanical connection of the contacts of the IC chip and the contacts of the switching substrate;

- filling the gap between the IC chip and the switching substrate with an elastic dielectric composition (Underfill), which serves to relieve the thermomechanical stresses arising between the IC chip and the switching substrate during subsequent technological actions and in operation, due to the difference in the thermal expansion coefficients of the IC crystal and switching Substrates (Microelectronics Packaging Handbook, Part I (Semiconductor Packaging), Second Edition, Edited by: Rao R. Tummala, Eugene J. Rymaszewski, Alan G. Klopfenstein, pI-493 - I-494, by Kluwer Academic Publishers, 1999 )

The known method has the following indisputable advantages:

- the group nature of the assembly, when all the contacts of the chip are simultaneously connected to the response contacts of the switching substrate;

- the relative ease of implementation of the group soldering process.

However, the method has a number of significant disadvantages, the main of which are the following:

- on the contacts of the crystal it is necessary to form precision mounting projections (bumps) of the same shape and height, which negatively affects the percentage of yield, cost and reliability of crystals for mounting using the "flip chip" method;

- in the process of soldering, there is a chance of “transferring” to the chip, which can lead to merging and short circuits between adjacent bumps from solder, which, in turn, forces you to take additional measures that negatively affect the cost of assembly of the flip chip assembly;

- a narrow gap between the surface of the crystal and the mounting surface of the switching substrate complicates the output of by-products of soldering, which remain in this gap, which negatively affects the reliability of the contact nodes during operation;

- the difference in the thermomechanical characteristics of the IC chip and the switching substrate, with a rigid “flip chip” design of the contact nodes, leads to large mechanical stresses in the contact nodes, up to their destruction under thermocyclic loads, which forces a narrow gap between the crystal and the switching substrate to be introduced elastic composition (underfill) for unloading stresses, which, ultimately, negatively affects the complexity and cost of assembly;

- the introduction of underfill in the gap between the IC chip and the switching substrate is a difficult problem when flip-chip assembling large crystals due to the formation of air cavities under the crystal that adversely affect operation.

The claimed invention proposes to use the capillary effect in the manufacture of contact nodes, which almost completely eliminates the disadvantages inherent in known contact nodes and the technology for their manufacture.

One of the main objectives of the method of manufacturing a contact node in oncoming contacts with a capillary connecting element was to determine the optimal parameters for the stable formation of a capillary connection in the manufacturing process of the contact node.

In the prior art, technical solutions have not been identified related to the determination of the main parameters that provide the necessary height for raising the solder melt in the capillary, which is a through metallized hole in the polyimide film (the last coating is 0.25 μm galvanic gold).

The term “capillarity” refers to interfaces that are sufficiently mobile to form an equilibrium shape. The most typical examples are menisci and droplets formed by liquids in air or in another liquid.

As is known, capillarity is associated with equilibrium configurations, which are studied in the general system of thermodynamics, and considers macroscopic and statistical behavior of interfaces, and not details of their molecular structure.

Free energy per unit surface area is equivalent to surface tension, defined as the force acting per unit length.

The concepts of surface free energy and surface tension can be illustrated by the following examples. First, consider a soap film stretched over a wire frame, one side of which is movable, as shown in FIG. Each movable element is affected by a force whose direction is opposite to the direction shown by the arrow in the diagram. If the magnitude of this force per unit length is denoted by γ, then the work performed when the movable element is displaced by a distance dx is equal to:

Equation (1) can be written as

where dA = 1 · dx is the change in surface area.

As a second example, consider the soap film forming the bubble of FIG. 2. In this case, γ is more conveniently expressed in the form of energy per unit surface. In the absence of fields, such as a gravitational field, the soap bubble has a spherical shape, which is characterized by a minimum surface area for a given volume bounded by this surface. Consider a soap bubble of radius r, shown in Figure 2. The total surface free energy of the bubble is 4πr ² γ. If the radius of the bubble is reduced by dr, then the change in the surface free energy is 8πrγdr.

Since the surface energy decreases during compression of the bubble, the tendency to compression should be compensated by the pressure difference ΔР on the film, so that the work against the pressure ΔР4πr ² dr is exactly equal to the decrease in the surface free energy. In this way,

or

As a result, we come to the important conclusion: the smaller the bubble, the greater the difference between the air pressure inside the bubble and outside.

The final state, shown by dashed lines, is mechanically equilibrium.

It should be noted that γ is usually defined as the surface tension of a single interface. Therefore, when describing soap or other bilateral films in equations (1) and (2), instead of γ, it is better to use the value 2γ.

Equation (4) is a special case of a more general relation - the basic equation of capillarity, obtained in 1805 by Jung and Laplace

where R1, R2 are constant radii of curvature.

Equation (5) is the main equation of the theory of capillary phenomena, and it will be widely used in the future.

In a first approximation, the phenomenon of capillary uplift can be interpreted based on the Young-Laplace equation. If the liquid wets the capillary wall, its surface should be parallel to the wall, and therefore, in general, the surface of the liquid should have a concave shape. The pressure difference at the liquid-gas interface is determined by equation (5), and its sign is such that the pressure in the liquid is less than in the gas phase. The authors showed that both radii of curvature (when they have the same sign) are always located on the side of the interface where the pressure is greater.

If the cross section of the capillary is round and its radius is not too large, the meniscus has the shape of an almost regular hemisphere (Figure 3), while both radii of curvature are equal to the radius of the capillary, and equation (5) can be reduced to

where r is the radius of the capillary.

Denote h the meniscus height above the flat surface of the liquid (for which ΔP = 0).

Then in equation (6) ΔР should be equal to the drop in hydrostatic pressure in the column of liquid in the capillary. Thus, ΔP = Δρgh, where Δρ is the density difference between the liquid and gas phases (ρ _carriage - 1.29 kg / m ³ ; ρ _POS-61 - 8540 kg / m ^3, respectively; Δρ = ρ _POS-61 , since ρ _cart. << ρ _POC-61 ), ag - acceleration of gravity.

Now equation (6) can be converted to

The value of a, defined by equation (8), is called the capillary constant. A similar equation can also be obtained for a liquid that does not wet the capillary wall, i.e. for a liquid in which the contact angle with the walls (contact angle) is not zero, but 180 °. However, in this case, we have a capillary lowering, while the meniscus in the capillary is convex, and h corresponds to the depth of the lowering of the meniscus (Figure 4).

In the general case, when the liquid contacts the walls of a round cylindrical capillary at a certain angle θ, and if the meniscus still has a spherical shape, then, as follows from simple geometric considerations, R ₂ = r / cosθ, and, since R ₁ = R ₂ , equation (7) takes the following form:

For accurate mathematical determination of the height of the capillary rise, it is necessary to take into account the deviation of the shape of the meniscus from the spherical, i.e. at each point of the meniscus, the curvature should correspond to ΔP = Δρgy, where y is the excess of the point over the liquid plane. This condition can be formulated by writing equation (5) at an arbitrary point (x, y) of the meniscus and replacing RR with the corresponding expressions from analytic geometry. It is also assumed that the cross section of the capillary is round, and, therefore, the meniscus has the shape of a rotation figure, as shown in Figure 5. The radius R ₁ lies in the plane of the sheet, and R ₂ in the perpendicular plane. In this way,

where y ^/ = dy / dx and y ^// = d ² y / d ² x.

From equation (10), one can obtain the exact expression for the total weight W of the liquid column. Let p = y ^/ and, therefore, y ^// = pdp / dy. Then equation (10) can be written as

Formally, W is defined by the equation

which, after replacing y with the corresponding expression found from equation (11), can be converted into the equation

The integrand of the last equation is equal to the total differential xp / (1 + ρ ² ) ^1/2 ; With this in mind, we accordingly write the solution of equation (13) in the following form:

By definition, p = dy / dx, therefore x = r, p = tanφ, where φ = 90 ° -θ. Substituting these limits, we obtain

Note that equation (15) exactly corresponds to the equation that can be written assuming that the meniscus “hangs” on the walls of the capillary and the column is held by the vertical component of the surface tension γcosθ multiplied by the perimeter of the section of the capillary 2πr. Thus, in this case too, the mathematical identity of the concepts of “surface tension” and “surface free energy” is observed.

It is known that surface tension is due to the fact that the molecules on the surface are attracted only to the molecules that are located under them. Therefore, they tend to clog into the fluid. As a result, a thin film is formed on the surface with a thickness of 2-3 layers of molecules, denser than the entire liquid, Fig.6. Another explanation is that the molecules of the surface layer have twice the potential energy than the molecules inside the liquid. In an effort to occupy the position with the least potential energy, the liquid molecules on the surface tend to be drawn into the liquid.

Thus, the liquid, under the action of internal forces of molecular attraction, seeks to reduce the free surface (that is, the surface of contact with air).

The density of surface energy (surface tension) is the ratio of the work required to increase the surface area to the magnitude of this increment to the area: γ = ΔW / ΔA.

Since the surface tension coefficient depends on the temperature, in this case, of the molten solder, it must be experimentally measured at different temperature values.

By measuring with a precision adhesiometer the force F that must be applied to increase the surface area of the liquid solder, the surface tension can be determined. To do this, use a wire frame l, which is lowered into the liquid, Fig.7.

Since the work is equal to the product of the displacement force, ΔW = F · Δs, and the change in surface area on both sides of the frame is ΔA = 2Δs · 1, the surface tension can be calculated by the formula: γ = F · Δs / 2Δs · l, respectively γ = F / 2l [N / m].

The measurement results are presented in table 1. A graph of the dependence of the surface tension coefficient of the POS-61 melt on temperature is shown in Fig. 8.

To measure the wettability angle by soldering a gold surface at different temperatures, an experiment was conducted including:

- preparation of a measuring stand (heating table, measuring system);

- preparation of doses of solder (cylinder d = 400 μm and h = 500 μm) and a gold surface (contact area 4 × 4 mm).

The solder on the gold surface was melted at different temperatures in vacuum (0.7-6Pa). Then, on the MII-4 microinterferometer, the wettability angle of the molten drop was measured.

When heated, not only the volume changes, but also the density of the liquid solder. To calculate the solder density, we use the formula: ρ _n = ρ ₀ / (1 + 3α · ΔТ), where

ρ ₀ is the solder density under normal conditions,

3α is the coefficient of linear expansion.

Thus, the authors obtained all the necessary dependencies and data for calculating the height of the rise of solder in the capillary, which, taking into account the obtained experimental data, takes the following form:

where ρ ₀ = 8540 kg / m ³ ; α = 21 · 10 ⁶ ° C ^-1 ;

h is the height of the solder in the capillary;

γ is the surface tension coefficient of solder;

θ is the wettability angle of the solder;

α is the coefficient of linear expansion of the solder;

ρ ₀ - solder density under normal conditions;

T ₀ - solder temperature in degrees Kelvin under normal conditions;

T _n is the temperature of the molten solder in degrees Kelvin.

The calculations show that with a capillary radius of 10 μm and a temperature change in the range from 493K to 543K:

- the coefficient of surface tension lies in the range of 0.52 ÷ 0.46 N / m;

- the wettability angle varies from 7 ° to 3 °;

- the height of raising the solder will be 1500 cm, provided that the dose of solder is not limited and the entire capillary is at a certain temperature.

Thus, the authors solved the problem of ensuring the creation of a capillary connecting element in the manufacture of the contact assembly on the opposite contacts, under specific conditions: when a metallized hole made in a film of a dielectric material was used as a capillary.

The problem to be solved in the proposed group of inventions, in terms of the method of manufacturing the contact node on the counter contacts with the capillary connecting element, is to create a method that allows the manufacture of a large number of contact nodes that electrically and mechanically connect two arrays of counter contacts located on two different carriers ( for example, when mounting IC crystals on the switching substrates of multi-chip modules or when mounting ICs in BGA packages on printed circuit boards), easy to implement, low cost and high reliability.

The task underlying the claimed group of inventions, in terms of a method of manufacturing a contact node in oncoming contacts with a capillary connecting element, achieving the above technical result, is solved by the fact that in the method of manufacturing a contact node on oncoming contacts with a capillary connecting element, including:

- applying thin film layers of metallization and solder to one of the flat contacts;

- the manufacture of the workpiece of the connecting element for the said oncoming contacts and its tinning with solder;

- tinning said solder response flat contact;

- the combination of oncoming flat contacts with the workpiece of the connecting element relative to the common axis passing through the centers of the said oncoming contacts, until they contact, with fixing alignment for the time of soldering;

- heating the contact zone of said oncoming contacts and the workpiece of the connecting element until the applied solder melts;

- lowering the temperature in the soldering zone until the curing of said solder between said counter contacts, with the formation of a connecting element of the contact node on the counter contacts;

in accordance with the invention

- the workpiece of the connecting element for the oncoming contacts is made in the form of a metallized capillary hole in the dielectric film, the outputs of which are limited by the end flanges on the surfaces of the said dielectric film, and the capillary hole is tinned with the said solder, along with the end flanges, while the longitudinal axis of the capillary hole coincides with the said axis corresponding flat counter contacts;

- said dielectric film being a carrier of said tinned capillary hole, during assembly of the contact assembly, is placed between said counter contact carriers so that the longitudinal axis of said capillary hole passes through the centers of said counter contacts orthogonal to the surfaces of said counter contact carriers and tinned capillary hole ;

- then they bring together the carriers of the oncoming contacts, on both sides of the said carrier of the tinned capillary hole, along the said axis, until the oncoming contacts come into contact with the mentioned end flanges of the tinned capillary hole;

- the region between the said oncoming contact carriers is evacuated to 0.1 atm, while fixing the relative position of the oncoming contact carriers and the tinned capillary hole carrier located between them;

- bring the temperature in the said region to the melting temperature of the solder, ensuring the rise of the molten solder into the tinned capillary hole from the oncoming contacts, also previously tinned with the said solder;

- during and after cooling and curing of the solder in the capillary hole, as well as in the gaps between the end flanges of the capillary hole and the corresponding counter contacts, a capillary connecting element is formed between said counter contacts, providing a rigid fixation of the solder in the metallized capillary hole of the said capillary connecting element of the contact node, both in the process of subsequent technological impacts, and in the process of its operation as part of a microelectron Noah equipment;

- the height of the solder in the capillary connecting element, in the process of forming a capillary connecting element, is determined by the formula:

where ρ ₀ = 8540 kg / m ³ ; α = 21 · 10 ⁶ ° C ^-1 ;

h is the elevation height of the molten solder in the capillary connecting element;

γ is the surface tension coefficient of solder;

θ is the wettability angle of the solder;

α is the coefficient of linear expansion of the solder;

ρ ₀ - solder density under normal conditions;

T ₀ - solder temperature in degrees Kelvin under normal conditions;

T _n is the temperature of the molten solder in degrees Kelvin;

- as well as the fact that on said flat contact located on one of the bearing surfaces, and / or on the counter counter flat contact located on another bearing surface, tinned protrusions are formed, partially or completely entering the hole of said capillary connecting element, which are used as elements of mutual basement of said counter contacts and capillary connecting element;

- as well as the fact that the protrusions on the oncoming contacts, partially or completely entering the holes of the capillary connecting element, are made in the form of identically formed doses of solder;

- and also the fact that one of the aforementioned bearing surfaces with contacts is a surface of an IC chip with contacts, and the other said surface carrying response contacts is a surface with response contacts of a switching substrate.

During the assembly of contact nodes connecting two arrays of oncoming contacts, an array of tinned contacts of one carrier (for example, on an IC chip), an array of tinned contact contacts on another carrier (for example, on a switching substrate) and an array of metallized tinned holes (tubular capillaries) in a film the carrier, placed between two arrays of oncoming contacts, are combined with each other, come close to contact, and after heating to the melting temperature, the molten solder placed on the oncoming x contacts, partially drawn into the metallized tinned holes from both ends under the action of capillary forces, forming, after cooling, a reliable connection of two arrays of oncoming contacts.

The essence of the invention lies in the fact that when interconnecting two arrays of oncoming contacts located on two parallel (coplanar) carriers, as happens, for example, when mounting an inverted IC chip (flip chip) on a switching substrate or mounting a packaged IC with BGA - conclusions on the printed circuit board, use a mounting strip made of insulating material, placed between the carriers of the arrays of oncoming contacts. Metallized tinned holes are formed in the gasket, located between pairs of connected oncoming contacts. At the contacts of both arrays, doses of solder are preliminarily applied. The metallized tinned holes become capillaries for the solder placed on the oncoming contacts, at the melting point of the solder. Thus, a gasket made of insulating material is the carrier of an array of capillary connecting elements for contact nodes connecting two arrays of counter contacts (for example, one contact system is on an IC chip, and the response contact system is on a switching substrate).

A method of manufacturing contact nodes at oncoming contacts through a mounting gasket by means of capillary connecting elements is quite simple and does not require sophisticated equipment with highly qualified staff.

The capillary effect provides high uniformity and quality of the joints, as well as a high percentage of yield of contact nodes during the assembly process, and ensures low cost of their manufacture.

The method is equally applicable both for mounting crystals as part of single-chip and multi-chip modules, and for mounting ICs in BGA packages on printed circuit boards.

Brief Description of the Drawings

The invention is illustrated by graphic materials on which are presented:

- figure 1 shows a frame with a soap film;

- figure 2 shows a soap bubble;

- figure 3 schematically shows a capillary rise;

- figure 4 schematically shows a capillary lowering;

- figure 5 schematically shows the image of the meniscus in the capillary, as a rotation figure;

- Fig.6 shows a schematic arrangement of molecules in the surface layer;

- Fig.7 shows a measurement circuit;

- on Fig presents a graph of the dependence of the surface tension coefficient of the melt POS-1 on temperature;

- figure 9 shows a symmetrical contact node on the opposite contacts with the connecting element in the form of a capillary hole, with end flanges, in a plane-parallel plate of dielectric material (phase matching);

- Fig. 9a shows the same symmetrical contact assembly at the oncoming contacts with a connecting element in the form of a capillary hole, with end flanges, in a plane-parallel plate of dielectric material (connection phase);

- figure 10 shows a symmetrical contact node at the oncoming contacts with a connecting element in the form of a capillary hole, with end flanges, inside of which an electrically conductive binder material is placed before assembly of the contact node (alignment phase);

- Fig. 10a depicts the same symmetrical contact node at the oncoming contacts with a connecting element in the form of a capillary hole, with end flanges, inside of which an electrically conductive binder material is placed before the assembly of the contact node (connection phase);

- figure 11 shows the contact node on the counter contacts with the connecting element in the form of a capillary hole with end flanges, in which the counter contacts are offset relative to each other in the plane of their carriers, and the longitudinal axis of the capillary hole passing through the centers of the contacts is inclined at an angle α <90 ° to surfaces bearing these contacts (alignment phase);

- Fig. 11a shows the same contact node at the oncoming contacts with the connecting element in the form of a capillary hole with end flanges, in which the counter contacts are offset relative to each other in the plane of their carriers, and the longitudinal axis of the capillary hole passing through the centers of the contacts is inclined under angle α <90 ° to surfaces bearing these contacts (bonding phase);

- Fig. 12 shows a symmetrical contact assembly at the oncoming contacts with a connecting element in the form of a capillary hole, with end flanges made in the form of a truncated cone, the smaller bell of which is connected to one oncoming contact, and the larger bell is connected to the other oncoming contact (alignment phase );

- Fig. 12a depicts the same symmetrical contact node at the oncoming contacts with a connecting element in the form of a capillary hole, with end flanges made in the form of a truncated cone, a smaller socket of which is connected to one counter contact, and a larger socket is connected to another counter contact ( connection phase);

- Fig.13 shows a symmetrical contact node on the opposite contacts with a capillary connecting element made of multi-channel, while the capillary channels are not electrically connected to each other, and each channel has its own end flanges (phase matching);

- Fig. 13a shows the same symmetrical contact assembly at the oncoming contacts with a multi-channel capillary connecting element, while the capillary channels are not electrically connected to each other, and each channel has its own end flanges (connection phase);

- Fig. 14 shows a symmetric contact assembly in oncoming contacts with a capillary connecting element made of multi-channel, while the capillary channels of the multi-channel connecting element are electrically connected by common flat conductive contacts made in the form of end flanges placed on the surfaces of a plane-parallel plate of dielectric material in which said multi-channel capillary connecting element is made (phase matching);

- Fig. 14a shows the same symmetrical contact node on the opposite contacts with a capillary connecting element made of multichannel, while the capillary channels of the multichannel connecting element are electrically connected by common flat conductive contacts made in the form of end flanges placed on the surfaces of a plane-parallel plate of a dielectric material in which said multi-channel capillary connecting element (connection phase) is made;

- Fig. 15 shows a symmetrical contact assembly at the oncoming contacts with a connecting element, which is a porous structure permeable to an electrically conductive binder material during the technological action (registration phase);

- on figa shows the same symmetrical contact node on the opposite contacts with the connecting element, which is a porous structure filled with an electrically conductive binder material during the technological action (connection phase);

- Fig. 16 shows a symmetrical contact assembly at the oncoming contacts with a capillary connecting element, in which technological protrusions are made on the surfaces of the opposing contacts, with an electrically conductive bonding material deposited on them, while the technological protrusions of the contact assembly are inserted partially or completely into the capillary hole , on both sides, providing mutual self-alignment of the said counter contacts and the capillary connecting element during the assembly of the contact node (fa for combining);

- Fig. 16a shows the same symmetrical contact assembly at the oncoming contacts with the capillary connecting element, in which technological protrusions are made on the surfaces of the opposing contacts, with a binder conductive material deposited on them, while the technological protrusions of the contact assembly are partially inserted into the capillary hole or completely, on both sides, providing mutual self-alignment of the said counter contacts and the capillary connecting element during the assembly of the contact node (connection phase);

- Fig.17 shows a symmetrical contact node on the opposite contacts with a capillary connecting element, in which technological protrusions are made on the surfaces of the opposing contacts, while at least one of the protrusions is made in the form of a ball of a binder of electrically conductive material, partially or completely placed in the capillary hole (phase matching);

- Fig.17a shows the same symmetrical contact node on the opposite contacts with the capillary connecting element, in which technological protrusions are made on the surfaces of the opposing contacts, while at least one of the protrusions is made in the form of a ball of a binder of conductive material, partially or completely placed in a capillary hole (connection phase);

- Fig. 18 shows a symmetrical contact assembly in oncoming contacts with a capillary connecting element, in which a plane-parallel plate of dielectric material is a carrier of holes, one of which, located between the opposite contacts, is a capillary connecting element for these counter contacts, and the other holes, which are not between the oncoming contacts, impregnated with an adhesive (adhesive) composition intended for bonding coplanar contact carriers in places with rim of contacts (phase alignment);

- Fig. 18a depicts the same symmetrical contact assembly in oncoming contacts with a capillary connecting element in which a plane-parallel plate of dielectric material is a carrier of holes, one of which located between the opposing contacts is a capillary connecting element for these oncoming contacts, and the others holes that are not between the oncoming contacts are impregnated with an adhesive (adhesive) composition intended for bonding coplanar contact carriers in s-free contacts (compound phase).

- Fig.19 shows the main stages of preparation, alignment and connection (assembly) of KU components in a single device - a contact node on the oncoming contacts with a capillary connecting element (KU on VK with KSE);

- Figure 20 shows a diagram of the basic process of photolithography;

- Fig.21 shows a diagram of the basic technological process for the manufacture of metallized holes in a polyimide film;

- Fig. 22 shows a photo of an experimental model of an assembly machine for assembling KU at VK with KSE;

- Fig.23 shows a block diagram of an experimental model of an assembly machine for assembling a KU on a VK with a SSC;

- Fig. 24 shows a photo of a sample of a single-chip module OKM-1600 based on a test chip 1 × 1 cm in size with a matrix of 40 × 40 = 1600 contacts assembled using an experimental sample of an assembly machine for assembling a KU on a VK with a SSC;

- Fig. 25 shows a photo of a sample of a multi-chip module MKM-3200 based on 8 test chips with a size of 1 × 1 cm with a matrix of 20 × 20 = 400 contacts, assembled using an experimental model of an assembly machine for assembling a KU on a VK with a SSC;

- Fig.26 presents a table of the dependence of the surface tension coefficient of the melt solder POS-61 on temperature in the range 493-543K.

Preferred Embodiment

One of the many possible options for the implementation of the contact node in oncoming contacts with the capillary connecting element shown in Fig.9 (phase alignment), contains: contact 1, placed on one of the coplanar carriers, for example, the upper carrier 2, which can be used, for example, a Si-crystal with active components, contact 3, placed on a second coplanar carrier, for example, the lower carrier 4, for which, for example, a Si-PCB switching substrate can be used. A plate of dielectric material, for example, a polyimide film 5 with a metallized hole 6 formed therein, is placed between the coplanar carriers 2 and 4 of the contact node. On the upper carrier 2, for which, for example, a silicon crystal is used, a conductive path 7 is applied, for example, aluminum connected to contact 1. A similar conductive path 8 is applied to the lower carrier 4 and connected to contact 3. The formation of one of the oncoming contacts, for example 1, is completed by applying to dose conductive binder material 9 (solder). In a similar manner, a second counter contact 3 is formed by applying a dose of a binder of electrically conductive material 10 (solder) to it. A coating of a similar binder material 12 is applied to the metallized surface 11 of the hole 6 and the end flanges 13 and 14 formed at the outputs of the hole 6 made in the dielectric film 5. Thus, the above describes the implementation of the main elements of the contact node on the counter contacts with the capillary an element. Further, these notations will be used to describe individual features and various embodiments of this contact node.

So, in the alignment phase (Fig. 9), contacts 1 and 3, located opposite each other - on the upper 2 and lower 4 carriers, respectively, are aligned relative to the common axis AA between themselves and the hole 6 in the dielectric film 5. On the said contacts 1 and 3 is a conductive binder material 9 and 10, respectively. On the inner metallized coating 11 of the hole 6 and the said end flanges 13 and 14 is a similar binder conductive material 12. Next, the connection phase.

In the connection phase (Fig. 9a), contacts 1 and 3 approach each other until they contact, respectively, the upper 13 and lower 14 end flanges of the metallized hole 6. At this point, the contact zone 1, 3 and hole 6 with the end flanges 13 and 14 is subjected to technological impact (for example, the temperature effect before melting of the binder of the electrically conductive material - solder), as a result of which the metallized hole 6 becomes a capillary for the binder of the electrically conductive material, which is in the process of The chemical action is drawn into the capillary from both contacts 1 and 3 under the action of capillary forces. After the cessation of the technological effect, the binder conductive material in the capillary, as well as between the flanges and counter contacts, hardens. In this case, a contact assembly is formed, consisting of two contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element 6, filled with a hardened binder conductive material.

The contact node at the oncoming contacts with the capillary connecting element can be made somewhat differently than described above. So doses of a binder of electrically conductive material 9, 10 can be placed not on contacts 1 and 3 before assembly of the contact assembly, but directly inside the metallized hole 6. Such an embodiment of the contact assembly is shown in FIG. 10.

In the alignment phase (Figure 10), contacts 1 and 3, located opposite each other - on the upper 2 and lower 4 carriers, respectively, are aligned relative to the common axis AA between themselves and the hole 6, with end flanges 13 and 14, in the dielectric film 5 filled with a conductive binder material 15.

In the connection phase (Fig. 10a), contacts 1 and 3 are brought closer to each other until they touch the upper and lower end flanges 13 and 14 of the metallized hole 6. At this point, the contact zone 1, 3 and hole 6 is subjected to technological influence (for example, temperature exposure to melting of the binder of the electrically conductive material (solder), as a result of which the metallized hole 6 becomes a capillary for the binder of the electrically conductive material 15, which wetts the contact kty 1 and 3. Moreover, the capillary forces do not allow the said binder conductive material 15 to propagate from the capillary 6 beyond the wetted contacts 1 and 3 and the said end flanges 13 and 14. After the termination of the technological action of the binder conductive material in the capillary, as well as between the said end hardens with flanges and counter contacts. In this case, a contact assembly is formed, consisting of two contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element filled with a hardened binder, conductive material.

In a very diverse practice of manufacturing microelectronic equipment, there are quite common cases where it is necessary to make a contact node in which the opposing contacts are offset from each other. Such an embodiment of the contact node at the oncoming contacts with the capillary connecting element is shown in FIG. 11.

In the alignment phase (Fig. 11), contacts 1 and 3, located opposite each other - on the upper 2 and lower 4 carriers, respectively, are aligned relative to the common axis AA between themselves and the inclined hole 6, with end flanges 13 and 14, in the dielectric film 5. At said contacts 1 and 3, there are doses of a binder of electrically conductive material 9 and 10, respectively. On the metallized coating 11 of the hole 6 and the said end flanges 13 and 14, is the same binder conductive material 12.

In the connection phase (Fig. 11a), contacts 1 and 3 are brought closer to each other until they touch the upper and lower end flanges 13 and 14 of the metallized hole 6. At this point, the contact zone 1, 3 and hole 6 is subjected to technological influence (for example, temperature exposure before melting the binder of the electrically conductive material - solder), as a result of which the metallized hole 6 becomes a capillary for the binder of the electrically conductive material, which is drawn into a pillar from both pins 1 and 3 under the action of capillary forces. After the termination of the technological effect, the binder conductive material in the capillary, as well as between the mentioned end flanges and counter contacts hardens. In this case, a contact assembly is formed, consisting of two contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element filled with a hardened binder, conductive material.

In accordance with the present invention, it is contemplated that the contact assembly can be made in on-going contacts with a capillary connecting element of various shapes and configurations. So, Fig. 12 shows a contact assembly in oncoming contacts with a capillary connecting element made in the form of a truncated cone.

In the alignment phase (Fig. 12), contacts 1 and 3, located opposite each other - on the upper 2 and lower 4 carriers, respectively, are aligned relative to the common axis AA between themselves and the conical hole 6, with end flanges 13 and 14, in the dielectric 5. In this case, the smaller bell of the capillary is connected to one of the contacts, and the larger bell of the capillary is connected to another counter contact. On the mentioned contacts 1 and 3 is a binder conductive material 9, 10, respectively. On the inner metallized coating 11 of the hole 6 and the end flanges 13 and 14 is the same adhesive electrically conductive material 12.

In the connection phase (Fig. 12a), contacts 1 and 3 are brought closer to each other until they touch the upper and lower end flanges 13 and 14 of the metallized hole 6. At this point, the contact zone 1, 3 and hole 6 with the end flanges 13 and 14 is subjected to technological exposure (for example, the temperature effect before melting of the binder of the electrically conductive material - solder), as a result of which the metallized hole 6 becomes the capillary for the binder of the electrically conductive material, which during technological process action is drawn into the capillary with both contacts 1 and 3 by capillary action. After the termination of the technological effect, the binder conductive material in the capillary, as well as between the mentioned end flanges and counter contacts hardens. In this case, a contact assembly is formed, consisting of two contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element filled with a hardened binder, conductive material.

On Fig presents the contact node on the opposite contacts, in which the capillary connecting element is made multi-channel.

In the alignment phase (Fig. 13), contacts 1 and 3, located opposite each other - on the upper 2 and lower 4 carriers, respectively, are aligned, relative to the common axis AA, between themselves and the end flanges 13 and 14 of the group of capillary channels 6 in the dielectric film 5. At the said contacts 1 and 3 is a binder conductive material 9, 10, respectively. On the inner metallized coating of the channels 6 and on the end flanges 13 and 14 is a similar binder conductive material 12.

In the connection phase (Fig.13a), contacts 1 and 3 are brought together towards contact with the upper and lower end flanges 13 and 14 of the metallized channels 6. At this point, the contact area 1, 3 and holes 6 is subjected to technological influence (for example, temperature exposure before melting the binder of the electrically conductive material - solder), as a result of which the metallized channels 6 become capillaries for the binder of the electrically conductive material, which is pulled into the capillary during the technological process channel channels from both contacts 1 and 3 under the action of capillary forces. After the termination of the technological effect, the binder conductive material in the capillaries, as well as between the mentioned end flanges and counter contacts hardens. In this case, a contact assembly is formed, consisting of two contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element, consisting of several channels not electrically connected to each other and filled with a hardened binder conductive material.

Unlike the previous version, the contact node at the opposite contacts with the capillary connecting element can be made in such a way that the capillary channels of the multichannel connecting element are electrically connected by common flat conductive contacts in the form of common end flanges placed on the surfaces of the dielectric film in which the said multichannel capillary connecting element. Such an embodiment of the contact node is shown in Fig. 14.

In the alignment phase (Fig. 14), contacts 1 and 3, located opposite each other - on the upper 2 and lower 4 carriers, respectively, are aligned relative to the common axis AA between themselves and the group of capillary channels 6, with common end flanges 13 and 14, in the dielectric film 5. At the mentioned contacts 1 and 3 is a binder conductive material 9, 10, respectively. On the inner metallized coating of the channels 6 and on the mentioned end flanges 13 and 14 is the same binder conductive material 12.

In the connection phase (Fig.14a), contacts 1 and 3 approach each other to contact the upper 13 and lower 14 end flanges of the capillary channels 6 on the surfaces of the film 5, common to the metallized channels 6. At this point, the contact area 1, 3 and holes 6 is subjected to technological influence (for example, the temperature effect prior to melting of the binder of the electrically conductive material - solder), as a result of which the metallized channels 6 become capillaries for the electrically conductive binder and the material, which the process of technological impact, is drawn into the capillaries from both contacts 1 and 3 under the action of capillary forces. After termination of the technological effect, the binder conductive material in the capillaries, as well as between the mentioned end flanges and counter contacts hardens. In this case, a contact assembly is formed consisting of two contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element consisting of several channels, filled with hardened binder conductive material.

The contact node at the oncoming contacts with the capillary connecting element can be made in such a way that the connecting element is a porous structure permeable to an electrically conductive binder material in the process of technological influence. Such an embodiment of the contact node is shown in Fig. 15.

In the alignment phase (Fig. 15), contacts 1 and 3, located opposite each other - on the upper 2 and lower 4 carriers, respectively, are aligned relative to the common axis AA between themselves and the porous structure 16 in the dielectric film 5. At the said contacts 1 and 3 is a binder of conductive material 9 and 10, respectively. The porous structure 16 is wettable and permeable to a binder electrically conductive material during technological exposure.

In the connection phase (Fig. 15a), contacts 1 and 3 are brought closer to each other until they contact the upper and lower ends of the porous structure 16. At this point, the contact zone 1, 3 and the porous structure 16 is subjected to technological influence (for example, the temperature effect before the binder melts) electrically conductive material - solder), as a result of which the porous structure 16 becomes wettable and permeable to the binder of the electrically conductive material, which, in the process of technological influence, is drawn into the porous st ukturu 16 with both contacts 1 and 3 by capillary action. After the cessation of the technological effect, the binder conductive material in the porous capillary structure 16 hardens. In this case, a contact assembly is formed, consisting of two contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element filled with a hardened binder, conductive material.

Another embodiment of the contact node at the oncoming contacts with the capillary connecting element is a contact node, in which technological protrusions are made on the surfaces of the oncoming contacts with an electrically conductive binder applied to them. The mentioned technological protrusions of the contact node enter the capillary partially or completely from its two sides, providing mutual self-alignment of the said counter contacts and the capillary connecting element during the assembly of the contact node. This embodiment of the contact node is shown in Fig.16.

In the alignment phase (Fig. 16), the technological protrusions 17 and 18 at the contacts 1 and 3, respectively, covered with a binder of conductive material 9 and 10, respectively, are brought together towards contact with the upper and lower end flanges 13 and 14 of the metallized hole 6 in the film carrier 5 and are combined with each other and with a metallized hole 6 relative to the common axis AA.

In the connection phase (Fig.16a), the zone of the technological protrusions 17 and 18 and the metallized hole 6 is subjected to technological influence (for example, temperature exposure before the binder is electrically conductive material - solder), as a result of which the binder of the electrically conductive material is drawn into the hole during the technological action 6 with technological protrusions 17 and 18 under the action of capillary forces. After the termination of the technological effect, the binder conductive material in the capillary structure, as well as between the mentioned end flanges 13 and 14 and the oncoming contacts hardens. In this case, a contact assembly is formed, consisting of two contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element filled with a hardened binder, conductive material, and the formed contact assembly is obtained by reinforced technological protrusions 17 and 18, which significantly increases the strength of the contact assembly.

The above-described variant of the contact node can be varied in terms of execution as follows - the technological protrusion, at least on one of the counter contacts of the said contact node, is a ball of a binder of electrically conductive material, partially or completely placed in a metallized hole. Such a contact node is shown in Fig.17.

In the alignment phase (Fig. 17), the technological protrusions 19 and 20, made in the form of balls of a binder of electrically conductive material formed on the contacts 1 and 3, are brought together towards contact with the upper and lower end flanges 13 and 14 of the metallized hole 6 in the film the carrier 5 and are combined with each other and with a metallized hole 6 relative to the common axis AA.

In the connection phase (Fig. 17a), the zone of the technological protrusions 19 and 20 and the metallized hole 6 is subjected to technological influence (for example, temperature exposure before the binder is electrically conductive material - solder), as a result of which the binder of the electrically conductive material is drawn into the hole 6 from the technological protrusions 19 and 20 under the action of capillary forces. After the termination of the technological effect, the binder conductive material in the capillary structure hardens. In this case, a contact assembly is formed, consisting of two contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element filled with a hardened binder, conductive material, and a ball 20 on contact 3.

A variant of the contact node at the oncoming contacts with a capillary connecting element having increased tightness and mechanical strength is shown in Fig. 18.

In this contact node, a plane-parallel plate of dielectric material 5 is a carrier of holes, one of which 6, with end flanges 13 and 14 located between the counter contacts 1 and 3, are capillary connecting elements for these counter contacts, and the other holes 6a, which are not are between the oncoming contacts, impregnated with the adhesive (adhesive) composition 21, intended for bonding coplanar carriers 2 and 4 of the said oncoming contacts in places free from contacts on the mentioned ositelyah.

In the alignment phase (Fig. 18), pairs of paired contacts 1 and 3, located opposite each other - on the upper 2 and lower 4 carriers, respectively, are combined with each other and the capillary hole 6, with end flanges 13 and 14, in the said plate of dielectric material 5, relative to the common axis A ₂ A ₂ . On the mentioned contacts 1 and 3, there is a binder conductive material 9 and 10, respectively. On the inner metallized coating of the hole 6, as well as on the mentioned end flanges 13 and 14 is the same binder conductive material.

In the connection phase (Fig. 18a), the pairs of mated contacts 1 and 3 are brought closer to each other until they touch the upper and lower ends of the metallized holes 6, and the adhesive composition 21, located in the remaining holes 6a, comes into contact with the bearing surfaces 2 and 4, free from oncoming contacts. At this moment, in the zone of contacts 1, 3 and holes 6 and 6a, a technological action is switched on, the nature of which is such that the metallized holes 6 become a capillary for a binder of electrically conductive material, which, in the process of technological influence, is drawn into the capillaries 6 from the counter contacts 1 and 3 under the action of capillary forces. After the cessation of the technological effect, the binder conductive material in the capillaries 6, as well as between the mentioned end flanges and counter contacts hardens, and the adhesive composition 21 fills all the remaining cavities between the carriers 2 and 4 and also hardens. As a result of technological influence, a contact assembly is formed, consisting of counter contacts 1 and 3, interconnected electrically and mechanically by a capillary connecting element 6, filled with a hardened binder, conductive material, and the contact carriers 2 and 4 are hermetically and firmly glued.

The following describes the manufacturing process of the contact node (KU) on the oncoming contacts (VK) with a capillary connecting element (KSE) with the following general characteristics (on the example of KU in Fig. 9): 2 - contact carrier 1 (silicon IC chip); 4 - contact carrier 3 (silicon switching substrate); 1 and 3 — contacts (contact pads) of A1 70 × 70 μm in size with metallization layers (adhesive layer Ti ~ 0.1 μm thick, conductive Cu layer ~ 1.0 μm, protective layer Ni ~ 0.1 μm, solder 9 , 10 SnBi ~ 15-20 μm - height along the upper edge of the meniscus); 5 - carrier capillary holes (polyimide film with a thickness of 50 μm); 6 - capillary hole (with an inner diameter of 20-30 μm), as well as 13 and 14 - upper and lower end flanges of capillary hole 6 with metallization layers (adhesive layer of Cr ~ 0.1 μm, conductive layer of Cu ~ 3-5 μm, a protective layer of Ni ~ 0.1 μm, solder 12 of SnBi ~ 3-5 μm, outer diameter of the flanges ~ 70 μm, width of the flanges ~ 10 μm).

The preparatory process for manufacturing KU (Fig. 9) includes two preparatory processes (preparation of contacts on carriers 2 and 4, and the technological processes for contacts 3 and 4 are the same, and preparation of carrier 5 of the capillary hole 6 with end flanges) and the assembly process of KU from prepared the mentioned parts (Fig.19).

The technological processes for processing contacts on IC crystals and a switching substrate are group (i.e., all contacts 3 or 4 of all carriers 1 and 2, respectively, placed on silicon wafers are processed simultaneously).

An important operation in the contact preparation process is the plasma-chemical cleaning of contact pads from Al from Al ₂ O ₃ (for example, at the Trion installation; a detailed description of the installation: O.D. Parfenov. Microcircuit technology. Higher School Publishing House, 1986, p. .226-227).

Then, at the mentioned Trion installation, in the same vacuum pumping cycle, the metallization layers are sequentially sprayed: an adhesive layer of Ti (0.1 μm), a conductive layer of Cu (1.0 μm) and a protective layer of Ni (0.1 μm )

After removing the wafers from the cleaning / spraying unit, standard photolithography with opening the windows is performed, in a dubbed photoresist, above the dusty contact pads in accordance with the scheme of Fig. 20 (O.D. Parfenov. Chip technology. Higher School Publishing House, 1986, pg. 90-112).

Then, in the opened windows, galvanic build-up of solder (SnBi, 15 μm) for metallization (Ni) is performed.

After removing the photoresist mask and washing the plates, chemical etching of the thin layers of metallization is performed in the reverse order of spraying (see clause 1.2. Above). In this case, the metallization layers under the galvanically expanded solder remain on the contact pads since the solder plays the role of a mask.

After melting the SnBi solder (at Т ~ 220 ° С), to give the solder protrusions the same shape as a convex meniscus with a height of ~ 20 μm, the preparation of contacts 1, 2 is completed.

After separation (scribing) of the plates into crystals and switching substrates (for example, using the semiautomatic scribing machine Almaz-M: O.D. Parfenov. Chip technology. Higher School Publishing House, 1986, p. 254), the crystals and substrates are stacked in a technological container for moving to the assembly site.

The manufacturing process and tinning of solder metallized holes, with end flanges, in a polyimide film is carried out according to the scheme shown in Fig.21 (I.N. Vozhenin and others. Microelectronic equipment on housing integrated circuits, M., Radio and communication, 1985, pp. .154).

Group manufacture of precision holes in the polyimide was carried out by the method of double-sided chemical etching in a KOH solution. The coordinates of the holes and their shape are set by photomasks in the process of photolithography according to the scheme of Fig.20. As a carrier of capillary holes, a Kapton-200H polyimide film from Du Point (USA) 50 μm thick was used.

It should be noted that there are other methods of forming holes in the PI film in predetermined coordinates, for example by laser drilling. Unlike a group chemical etching process, laser drilling is a sequential procedure that requires sophisticated equipment for its implementation.

Metallization of the holes and surfaces of the polyimide film was carried out on the UVN-71-P1 installation, modified for plasma-chemical cleaning and magnetron sputtering of two metals in a single vacuum pumping cycle. The heating time in the vacuum chamber is 25 minutes, which allows reaching 150 ° C, the argon working gas pressure during plasma-chemical cleaning is 4.9 · 10 ^-2 Pa, and when spraying metallized layers, 2.7 · 10 ^-1 Pa.

Polyimide substrates were metallized with copper with a purity of 99.9%. The specific resistance of the obtained copper films did not exceed 2.0 μOhm / cm, and the adhesion was not less than 400 g / cm.

The Cr-Cu-Cr layers deposited on both surfaces of the film and in the holes will serve as one of the electrodes in the electrochemical (galvanic) deposition and growth of Cu-Ni-SnBi in holes 6 and on their end flanges 13 and 14. After 2-sided photolithography according to the scheme in accordance with Fig. 20 and opening the photoresist mask of round windows (with a diameter of -70 μm) on both sides of the holes, Cr was etched to the Cu layer inside the holes and within the boundaries of the formed end flanges.

Then, in accordance with the scheme of Fig. 21, electrochemical (galvanic) deposition of pure copper (~ 3 μm), a protective layer of Ni and subsequent deposition of a layer of solder (SnBi ~ 5-7 μm) were performed on the surfaces of the holes and the above-mentioned flanges freed from Cr )

After the photoresist is removed on both sides of the PI film, the Cr-Cu-Cr layers are chemically etched on both sides of the PI carrier 5. The SnBi solder layer in the holes and flanges acts as a protective mask for the underlying Cr-Cu-Ni layers, protects these layers, providing high adhesion resistance of capillary holes with end flanges on the PI carrier.

After washing, drying and cutting PI carriers (there can be several of them on one PI substrate), they undergo visual and electrical control (for short circuit and breaks), then they are placed in technological containers and delivered to the assembly of the control unit.

The manufacturing process of the contact node (KU) at the oncoming contacts with the capillary connecting element is completed by the process of assembling the KU by vacuum soldering.

Since the vacuum soldering method was used mainly for the assembly of polyimide multilayer printed circuit boards and the available equipment did not meet the requirements of the KU assembly on this application (there was no system for combining contacts 1 and 3 with a capillary hole 6), the applicants developed, manufactured and tested (specially created for this test structures) an experimental model of the assembly machine, which demonstrated the feasibility of the technical solutions disclosed in this application. A photo of this sample is shown in Fig.22. 23 is a block diagram of said assembly machine.

A sample assembly machine was created on the basis of a desktop installation (907.250 from FRITSCH, Germany) for the precise combination of a flip chip and BGA components and their mounting on patch substrates and printed circuit boards (main characteristics: max component dimensions - 48 × 48 mm; max dimensions switching substrate - 280 × 230 mm; alignment accuracy - ± 5 microns).

The chip 12 (Fig. 23) is fixed, downward contact, by a vacuum suction cup 23 on the upper heater 7 with a temperature sensor 27 under the lid 11 of the vacuum microchamber, which is formed when the lid 11 is pressed all the way down to the ground surface of the base 14 containing the lower heating element 25 with the sensor temperature 28, on which, through the base pins 38, the switching substrate 9 is installed, with the contacts facing up, and on it, through the mentioned base pins, the PI carrier of the capillary holes 39 is laid. For the duration of the combination of hours IP 12 and the PI carrier 39, the chip 12 with the top cover 11 rises up so that between the chip 12 and the PI carrier 39, a dual prism 8 (on the swivel bracket - not shown in the block diagram) of the optical visual inspection system can be freely inserted, through a video camera 21 and a color TV monitor 22, and combining the upper and lower oncoming contacts.

The combination of oncoming contacts is done manually as follows. The base 14, with the PI carrier 39 and the switching substrate 9, located on the coordinate table 18, moves in the XY plane by the manipulators 36 (X) and 37 (Y). The rotation of the chip 12 around the Z axis is carried out by the drive 10 under the control of the manipulator 20. By controlling the X, Y and Z coordinates of the manipulators 36, 37 and 20 and controlling on the color screen the mutual movement of the chip contacts and the holes of the PI carrier 39 capillary holes (already aligned with the contacts substrate 9 along the base pins 38), the operator ensures that the contact images of the chip 12 and the response capillary holes on the PI carrier 39 are fully aligned vertically ~ 10 cm apart (the height of the inserted prism is ~ 8 cm).

Next, the operator removes the prism from the area between the chip 12 and the base 14 of the vacuum microchamber, and all subsequent operations are performed automatically under the control of the controller 17.

Using the precision screw 6, the bracket 5 with the chip 12, under the control of the controller 17, is lowered until it touches the PI carrier 39, without violating the previous alignment, with a soft fixation of the chip 12 in this position for the time of soldering. Then, the lid 11 is lowered until the vacuum microcamera closes, and, according to the specified program, the vacuum pump (turned on in Fig. 23 not shown) and the heaters 7 and 25 are turned on under the control of temperature sensors 27 and 28, respectively, which provide the necessary temperature-time mode of soldering in structure "chip - PI carrier - substrate". At the end of the soldering, the microcamera is evacuated, the chip 12 is disconnected from the vacuum suction cup 23, the assembly 5 with the cover 11 rises, the substrate 9 with the soldered chip 12 is removed from the base pins 38 and the installation is ready for a new cycle, which lasts ~ 1 min.

To the block of the programmable (via an external PC) controller 17 are connected position sensors 29, 30 and 31 of the stepper motor 1, gearbox 2 of the screw 6 and the stepper motor 3, respectively, temperature sensors 27 and 28, and also, along line 26, the control unit 16 of the stepper motors 1, 3 and heaters 7 and 25, which also controls, along line 24, the micropump unit 15, which through a hose 13 is connected to the base 14 of the vacuum microchamber.

The inclusion and indication of the health of blocks 16 and 17 are carried out by illuminated keys 35 and 32, 33, 34.

The described experimental assembly machine made it possible to obtain test samples of single-chip modules (OKM) with 1 × 1 cm test chips having 400 contacts (in an array of 20 × 20 contacts) and 1600 (40 × 40) contacts (photo OKM-1600 is shown in Fig. 24 )

In addition, we obtained samples of a multi-chip module (MCM) with dimensions of 35 × 70 mm for 8 test chips 1 × 1 cm with 400 contacts (in a matrix of 20 × 20 contacts) - a total of 8 × 400 = 3200 KU on the opposite contacts with capillary connectors elements (photo - Fig.25).

Industrial applicability

The implementation of the contact node with a capillary connecting element, in accordance with the present invention can significantly improve the quality characteristics of the contact node: strength (peel, vibration, shock, acceleration), uniformity of characteristics during the group assembly process (reproducibility), stability in time and in the process operation (reliability), stability in the temperature range and during thermal cycles, compactness (installation density), impact on performance. In addition, this implementation of the contact node also provides a significant reduction in the cost of its manufacture by reducing: material consumption, reducing the price of materials (eliminating the use of scarce and precious materials), the complexity of preparatory operations, ensuring manufacturability, controlability, environmental friendliness of preparatory and finishing procedures and reagents.

Reducing the complexity and cost of preparatory operations occurs due to the elimination of the need to form precision spherical bumps on the contacts of the IC crystals.

High manufacturability and high yield of contact assemblies during assembly is ensured by the use of capillary forces in the manufacturing process of contact assemblies, which exhibit high efficiency in such joints.

High uniformity in the manufacturing process of contact nodes is due to the property of the capillary to “compensate” for an overdose of solder on the opposite contacts.

The increase in the strength of the contact node and resistance to thermal cycles (especially in systems such as "silicon on silicon") are due to the proposed design of the capillary connecting element in an elastic medium of a durable dielectric.

Significantly reduced dimensions of the contact node made it possible to ensure low specific capacitive and inductive characteristics that are not achieved by any known contact node design, which is especially important when using contact nodes in structures operating in the GHz frequency range.

Table 1 T, K 493 503 513 523 533 543 γ, N / m 0.52 0,500 0.494 0.480 0.478 0.461

Claims (35)

1. The contact node on the oncoming contacts, consisting of at least two flat contacts, interconnected electrically and mechanically by a connecting element made in the form of a bridge of electrically conductive material, with each of these contacts placed on a flat surface of one of the two coplanar carriers, the contacts are oriented towards each other and aligned with each other relative to a common axis orthogonal to the coplanar carriers and passing through the contact centers, and the gap between the coplanar by the opposite contact carriers and around the connecting element is filled with a dielectric material, characterized in that the connecting element is made in the form of a capillary with end flanges, filled partially or fully with an electrically conductive binder material drawn into the said capillary from the counter contacts on which it was previously placed, under the action of capillary forces arising from the transition of a binder of an electrically conductive material to a liquid state during technological action during assembly contact node, with the formation after the termination of the technological impact of a mechanically stable electrically conductive connection between the oncoming contacts, and the said capillary is made in the form of a hole coated inside the said wettable electrically conductive binder material in a plane-parallel plate of dielectric material, which is the carrier of the capillary connecting element and is placed in the gap between coplanar carriers of oncoming contacts, the longitudinal axis of the capillary passing through the centers of said counter contacts orthogonal to the surfaces of said counter contact carriers, and said capillary end flanges located on the surfaces of said plane-parallel capillary connecting element carrier are aligned end-to-end with counter contacts and mechanically and electrically connected to them by a thin layer of said electrically conductive binder material. 2. The contact node according to claim 1, characterized in that said electrically conductive binder material is made of solder, and said technological impact is thermal. 3. The contact node according to claim 1, characterized in that said electrically conductive binder material is gel-like and wetts the inner surface of the capillary, its mentioned flanges and said counter contacts both during and after the termination of technological and other influences. 4. The contact node according to claim 2 or 3, characterized in that said electrically conductive binder material is preliminarily placed before the assembly of said contact nodes inside a capillary hole. 5. The contact node according to claim 1, characterized in that said counter contacts are displaced relative to each other in the planes of their carriers, and the longitudinal axis of the capillary connecting element passing through the centers of the contacts is inclined at a corner α <90 ° to the surfaces bearing these contacts . 6. The contact node according to claim 1, characterized in that the capillary connecting element is made of a cylindrical shape. 7. The contact node according to claim 1, characterized in that the capillary connecting element is made in the form of a truncated cone, and the smaller bell of the capillary is connected to one oncoming contact, and the larger bell of the capillary is connected to another oncoming contact. 8. The contact node according to claim 7, characterized in that said counter contacts are offset relative to each other in the planes of their carriers, and the longitudinal axis of the capillary connecting element, made in the form of a truncated cone, passing through the centers of the contacts, is inclined to the planes bearing these contacts at an angle β <90 °. 9. The contact node according to claim 1, characterized in that the capillary connecting element is multi-channel. 10. The contact node according to claim 1, characterized in that the capillary connecting element is a porous structure that is permeable to an electrically conductive binder material during the technological action during the assembly of the contact node. 11. The contact node according to claim 1, characterized in that the inner surface of the capillary connecting element is made in the form of a surface of revolution relative to the longitudinal axis of the capillary. 12. The contact node according to claim 1, characterized in that the inner surface of the capillary connecting element is made in such a way that sections orthogonal to the longitudinal axis of the capillary are polygons. 13. The contact node according to claim 1, characterized in that the inner surface of the capillary connecting element is made in such a way that sections orthogonal to the longitudinal axis of the capillary are smooth closed curves. 14. The contact node according to claim 1, characterized in that the inner surface of the capillary connecting element is made in such a way that sections orthogonal to the longitudinal axis of the capillary are ellipses. 15. The contact node according to claim 1, characterized in that on the surfaces of the oncoming contacts technological protrusions are made with a bonding electrically conductive material deposited on them, while the said technological protrusions of the contact node enter the capillary partially or completely from its two sides, providing mutual self-alignment of the aforementioned counter contacts and capillary connecting element in the process of assembly of the contact node. 16. The contact node according to item 15, characterized in that the technological protrusion, at least on one of the oncoming contacts of the said contact node is made in the form of a spherical protrusion of a binder of conductive material, partially or completely placed in the capillary during alignment during assembly contact node. 17. The contact node according to clause 15, characterized in that both of the said counter contacts have identical technological protrusions in size and shape. 18. The contact node according to clause 15, characterized in that both said oncoming contacts have technological protrusions of different sizes and shapes, and the sockets of the capillary connecting element associated with them are made of various sizes and shapes and are complementary to the corresponding technological protrusions at the oncoming contacts. 19. The contact node according to claim 1, characterized in that the said plane-parallel carrier of the capillary connecting element is made in the form of a film of elastic material. 20. The contact node according to claim 19, characterized in that the said film is made of polyimide. 21. The contact node according to claim 1, characterized in that around the capillary connecting element made in the aforementioned plane-parallel carrier of dielectric material, this carrier has holes filled with an adhesive composition that glues the coplanar contact carriers in places free of contacts. 22. The contact node according to claim 1, characterized in that the said plane-parallel carrier of dielectric material, in which capillary connecting elements are formed, is made in the form of a rigid plate having thermomechanical characteristics identical to the thermomechanical characteristics of oncoming contact carriers. 23. The contact node according to item 22, wherein the carrier of the capillary connecting elements is made of either glass or oxidized silicon. 24. The contact node according to claim 1, characterized in that the carriers of capillary connecting elements and oncoming contacts are made of the same material. 25. The contact node according to paragraph 24, characterized in that both of these bearing surfaces with counter contacts are made of either silicon or gallium arsenide or other semiconductor material, which, in addition to counter contacts, additionally have active and / or passive components and conductive tracks made according to planar technologies of microelectronics. 26. The contact node according to claim 1, characterized in that on the surfaces of the plane-parallel carrier of capillary connecting elements are conductive tracks that connect at least two capillary connecting elements. 27. The contact node according to p. 26, characterized in that on the surfaces of the aforementioned plane-parallel carrier of the capillary connecting element is placed power bus and ground bus. 28. The contact node according to claim 1, characterized in that the carrier of the capillary connecting elements is made in the form of a plane-parallel plate of electrically conductive material coated with a thin layer of insulating material, including the inner surfaces of the holes, and the capillary connecting elements, as well as active and / or passive components and conductive paths are made over said thin layer of insulating material. 29. The contact node according to p. 28, characterized in that the conductive base of the carrier of capillary connecting elements is made of either copper or aluminum. 30. The contact node according to clause 29, wherein the conductive carrier base of the capillary connecting elements, made of either copper or aluminum, is used as a ground bus. 31. The contact node according to claim 1, characterized in that the said carriers of the oncoming contacts, as well as the carrier of the capillary connecting elements located between the said carriers of the oncoming contacts, are made of various materials having the same thermomechanical characteristics. 32. A method of manufacturing a contact node in oncoming contacts with a capillary connecting element, made in accordance with claim 1, comprising
applying thin film layers of metallization and solder to one of the flat contacts;
the manufacture of a blank of the connecting element for said oncoming contacts and its tinning with solder;
tinning with said solder of a reciprocal flat contact;
the combination of oncoming flat contacts with the workpiece of the connecting element relative to the common axis passing through the centers of the said oncoming contacts, until they contact, with fixing the alignment for the soldering time;
heating the contact zone of said counter contacts and the workpiece of the connecting element until the applied solder melts;
lowering the temperature in the soldering zone until the curing of said solder between the said counter contacts with the formation of the connecting element of the contact node on the counter contacts;
characterized in that
the blank of the connecting element for the oncoming contacts is made in the form of a metallized capillary hole in the dielectric film, the outputs of which are limited by the end flanges on the surfaces of the said dielectric film, and the capillary hole is tinned with the said solder, along with the end flanges, while the longitudinal axis of the capillary hole coincides with the axis of the corresponding flat oncoming contacts;
said dielectric film being a carrier of said tinned capillary hole, during assembly of the contact assembly, it is placed between said counter contact carriers so that the longitudinal axis of said capillary hole passes through the centers of said counter contacts orthogonally to the surfaces of said counter contact carriers and tinned capillary hole;
after which the carriers of the oncoming contacts are brought together, on both sides of the said carrier of the tinned capillary hole, along the said axis, until the oncoming contacts come into contact with the mentioned end flanges of the tinned capillary hole;
the region between the said oncoming contact carriers is evacuated to 0.1 atm, while fixing the relative position of the oncoming contact carriers and the carrier of the tinned capillary hole located between them;
adjusting the temperature in said region to the melting point of the solder, allowing the molten solder to rise into the tinned capillary hole from the oncoming contacts tinned with said solder;
during cooling and curing of the solder in the capillary hole, as well as in the gaps between the end flanges of the capillary hole and the corresponding counter contacts, a capillary connecting element is formed between the said counter contacts, providing rigid fixation of the solder in the metallized capillary hole of the said capillary connecting element of the contact node, in the process subsequent technological impacts and during its operation as part of microelectronic equipment;
the height of the solder in the capillary connecting element in the process of forming a capillary connecting element is determined by the formula:

where ρ ₀ = 8540 kg / m ³ , α = 21 · 10 ⁶ ° C ^-l ,
h is the height of the solder in the capillary;
γ is the surface tension coefficient of solder;
θ is the wettability angle of the solder;
α is the coefficient of linear expansion of the solder;
ρ ₀ - solder density under normal conditions;
T ₀ - solder temperature in degrees Kelvin under normal conditions;
T _n is the temperature of the molten solder in degrees Kelvin. 33. The method according to p. 32, characterized in that on the said flat contact located on one of the bearing surfaces and / or on the counter oncoming flat contact located on the other bearing surface, tinned protrusions are formed, partially or completely entering the hole of said capillary a connecting element, which are used as elements of the mutual basement of said counter contacts and a capillary connecting element. 34. The method according to p. 33, characterized in that the protrusions on the oncoming contacts, partially or fully included in the holes of the capillary connecting element, are made in the form of identically formed doses of solder. 35. The method according to p, characterized in that one of the aforementioned bearing surfaces with contacts is the surface of the IC chip with contacts, and the other said surface bearing the response contacts is a surface with response contacts of the switching substrate.

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