RU2702705C1 - Multichip module - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: multi-level multichip module includes at least two circuit boards and two switching boards which are equal in planar dimensions, which together with electronic components form a module level. Levels of the module are interconnected mechanically and electrically by means of switching frames of the same planar dimensions as switching boards. Number of frames for interconnection of module levels is selected sufficient for placement in formed inner cavity of electronic components. Connection of each new level to number of already existing in module reproduces configuration of interface of docking, therefore module has open architecture and allows to increase levels in it. In order to ensure unification of the switching board, the electronic components are mounted on it through a circuit board with the original topology of the horizontal electrical wiring. In order to provide possibility of wireless commutation of circuit board with switching board, in the latter there is a through-window which is slightly smaller than circuit board. Circuit board is installed on the switching board so that the electronics components are in the switching board window, and the corresponding circuits of the contact pads of the mounting and switching boards coincide. In such situation, horizontal electric wiring of the switching board consists only in switching of contact pads of its external and internal circuits, i.e. it ceases to be original and suitable for use in modules with another set of electronic components.

EFFECT: invention can be used in production of multilevel multichip modules in three-dimensional assembly with improved operational characteristics.

3 cl, 10 dwg

Description

Technical field

The invention relates to electronic equipment and can be used in the manufacture of multi-level multi-chip modules in a three-dimensional assembly, with improved operational characteristics, as well as having a high interspecific functional density due to the combination of packaged and open-frame electronic components of various types, including VLSI, MEMS, products piezoelectronics and passive elements.

State of the art

Multi-chip modules solve the problem of layout and electrical switching according to a given electrical circuit of various electronic components in a limited space. Depending on the configuration of this space, two- and three-dimensional modules are separated. In any case, the module includes two or more circuit boards with electrical wiring, which by stacking on top of each other are stacked in the vertical direction. Packaged boards vary in function and design. In some cases, the package of boards is placed on a base having electrical terminals of the module as a whole.

By functional purpose, these boards can be divided into three groups: the first group - boards designed only for the mechanical installation and electrical switching of electronic components on this board among themselves, the second group - boards that include the function of boards of the first group, but additionally provide vertical electrical switching with lower and higher lying boards, the third group - boards designed for vertical switching of boards in the module and for the formation in the module of the internal space for placement in them electronic components.

In the literature and patent descriptions on relevant topics, including those cited in this application, a uniform terminology has not yet been established with respect to these groups of boards and various terms are used with respect to the same functional element of the module. For example, a board of the second group [Patent DE 102006000622 (A1) 2007.07.12] is referred to as an “auxiliary plate”, or [Patent US 005703753A 12.30.1997] as an “interposer”. At the same time, [Patent US 6,407,450 B1 06/18/2002, Patent US 006618267 B1 09/09/2003] the term "interposer" refers to the third group of cards, which performs exclusively the role of vertical connection of other boards in the module.

In this regard, in order to adequately describe the essence of various technical solutions that existed at the time of filing this application, when analyzing the prior art in the field of multi-chip modules, we introduce a common terminology for the main components of such modules.

Boards of the first group - circuit boards. Boards of the second group - switching boards. Boards of the third group - switching framework.

Circuit boards have only horizontal electrical wiring. Horizontal wiring is carried out in the plane of the board in the form of, as a rule, thin 0.1-50 microns of electrically conductive lines with a width of several tens or hundreds of micrometers by lithography or silk screen printing. These wiring lines begin on the internal contact pads of the circuit board, intended for switching with the output contact elements of electronic components, and end on the external - output contact pads of the circuit board, forming a one-sided circuit. On the way from internal contact pads to external wiring lines, they can intersect, forming a topological drawing of the electrical circuit being implemented. With a complex electrical circuit and a large number of electronic components placed on the board, the electrical wiring can be multi-level, i.e. made on one side in several levels separated by dielectric layers. Moreover, multi-level wiring can be performed on both sides of the board. Such a board has a two-sided multi-level wiring and allows the installation of electronic components on both sides of the circuit board.

Patch boards have horizontal and vertical electrical wiring. The boards have a two-sided external circuit of electrical contacts, made, as a rule, on the periphery of the board along its perimeter. In this case, the corresponding areas of the external circuit on the front and back of the board are electrically connected using one or another element of vertical electrical switching. For multi-layer execution of boards, the vertical switching element is performed using internal horizontal electrically conductive layers, as is done, for example, in patent DE 102006000622 (A1) 2007.07.12. In other cases, the vertical galvanic connection is implemented using vertical metallized holes [Patent US 005703753 A 12.30.1997]. The electronic components are mounted on the circuit board either directly [US Patent 6,407,450 B1 06/18/2002, Patent US 006618267 B1 09/09/2003], or together with a circuit board [Patent US 008199510 B2 12/06/2012, Patent US 20060108676 A1 05/25/2006, US Patent 20090014890 A1, 1/15/2009].

The switching frames have only vertical electrical wiring and represent the structural element of the module, made on the basis of the board with a large through window in their central part, giving such boards the geometry of the frame. The switching frames are an intermediate element between the switching boards and are used to spread the switching boards vertically in the package in order to create space for electronic components installed on the higher and lower switching boards [Patent US 006618267B1 09.09.2003, Patent US 008199510B2 12.06. 2012, Patent US 20060108676 A1 05.25.2006]. In order to prevent such intermediate elements from disturbing the vertical switching between the switching boards in the frame body, a two-sided circuit of electrical contacts with the vertical switching elements is made, by analogy with the switching boards.

Assembly as a part of a patch board, sometimes together with a circuit board, sometimes without it, depending on the direct [Patent US 6,407,450 B1 06/18/2002, Patent US 006618267B1 09/09/2003, Patent US 006618267 B1 09/09/2003,] or indirect [Patent US 008199510 B2 12/12/2012, Patent US 20060108676 A1 05/25/2006, Patent US 20090014890A1, 01/15/2009] the placement of electronic components on the patch board, forms the level of a multi-level three-dimensional module (in the terminology of US 20060108676 A1 05/25/2006 - "individual packages" ) The connection of these levels through a switching frame ensures the mechanical integrity of the module and the electrical switching of the parts of the electrical circuit of each circuit board into a single electrical circuit of the module, as is done [Patent US 006618267 B1 09.09.2003, Patent US 008199510 B2 12.06.2012, Patent US 20060108676 A1 May 25, 2006, Patent US 20090014890 A1, January 15, 2009] and, in principle, can be done [Patent DE 102006000622 (A1) 2007.07.12, Patent US 6,407,450 B1 06/18/2002].

Structural solutions [Patent US 005703753 A 12.30.1997, Patent WO 01/08187 A1, 02/01/2001] are not the objects of consideration of this application. They relate to two-dimensional multi-chip modules of the type of radio units for slot assemblies of larger units, for example, computers [Patent US 005703753A 12.30.1997]. Further on the example of [Patent US 005703753A 12.30.1997] more about the design of a two-dimensional module. As part of the design of [Patent US 005703753 A 12.30.1997] there is one switching frame (in the terminology of the authors [US Patent 005703753 A 12.30.1997] - “interposer 12” with a window), on the bottom of which a mounting plate with electronic components is connected (in the terminology of the authors [Patent US 005703753 A 12.30.1997] - "multi-chip module 13"). The solution allows the installation of a circuit board with additional electronic components on the upper side of the switching frame. A heat sink element can be installed below the circuit board. All boards and the frame are mechanically connected to the module by a threaded screw, which, of course, is unacceptable for three-dimensional microassemblies, where to ensure the installation of open-frame VLSI and other electronic chips with micrometric contact pads, the module uses patch boards based on brittle ceramic and single-crystal silicon. However, [Patent US 005703753A 12.30.1997, Patent WO 01/08187 A1, 02/01/2001] all the basic components for three-dimensional modules are used. However, the designs [US Patent 005703753 A 12.30.1997, Patent WO 01/08187 A1, 02/01/2001] have only one or two levels of a module with a large number of electronic components in each, therefore it is not a multi-level module. In addition, its planar dimensions, which is characteristic of any two-dimensional assembly, are large in relation to the height of the module. Because of this, such assemblies do not provide resistance to mechanical overloads, including those of inertial nature, leading to bending deformations of the structure. Meanwhile, the acquisition of just such stability was one of the incentives for the development of three-dimensional modules worldwide.

Technical solutions presented in patents DE 102006000622 (A1) 2007.07.12, US 6,407,450 B1 06/18/2002, US 006618267 B1 09/09/2003, US 008199510 B2 12.06.2012, US 20060108676 A1 05/25/2006, US 20090014890 A1, 01/15/2009 describe an object that is closer to the claimed decision to create a multi-level multi-chip module. Patents DE 102006000622 (A1) 2007.07.12, US 6,407,450 B1 06/18/2002, US 006618267 B1 09/09/2003 suggest the installation of electronic components directly on the circuit board. In patents US 008199510B2 06/12/2012, US 20060108676 A1 05/25/2006, the installation of electronic components is carried out on a circuit board, which in turn is installed on a circuit board. In US patent 20090014890 A1, January 15, 2009 there are no switching boards, the circuit board is made with a central through window allowing additional switching of the only electronic component with the underlying solid circuit board referred to as [chip holder US Patent No. 20090014890 A1, January 15, 2009] ". The entire combination of circuit boards is mounted on the base of the module and electrically connected to it by wire switching.

The most structurally and technologically sophisticated and, therefore, expensive are the switching boards. In the solutions [Patent US 6,407,450 B1 06/18/2002, Patent US 006618267 B1 09/09/2003, Patent US 006618267 B1 09/09/2003] the switching board belongs to the category of original products, because when changing the set of electronic components and / or circuitry, you need to re-develop and make the circuit board. When using a relatively simple wiring board [Patent US 008199510 B2 06/12/2012, Patent US 20060108676 A1 May 25, 2006, Patent US 20090014890 A1, January 15, 2009], the circuit board becomes unified within certain limits, and only the circuit board is subject to re-development. However, [Patent US 008199510 B2 12/12/2012, Patent US 20060108676 A1 05/25/2006, Patent US 20090014890 A1, 01/15/2009] installing electronic components through a circuit board means mandatory wire switching between the circuit board and the circuit board, which degrades reliability and technical specifications module.

Thus, today there is no solution for a multi-level three-dimensional module, in which the unification of the circuit board would be possible at the same time, as well as the absence of wire installation in the module, which could increase the manufacturability, technical and operational characteristics of the multi-level multi-chip module, as well as reduce its cost.

Brief Description of the Drawings

FIG. 1. The layout using the switching frames of a multi-level multi-chip module from the levels in the composition of the switching and circuit board with electronic components.

FIG. 2. An example of a circuit board with horizontal electrical wiring.

FIG. 3. An example of a unified patch card with a through window.

FIG. 4. Circuit board assembly with electronic components.

FIG. 5. The level of the module in the circuit board assembly with the circuit board and electronic components.

FIG. 6. A switching frame with a contour of bilateral contact pads electrically connected by vertical switching elements.

FIG. 7. The level of the module with attached mounting frames, filled with a compound, ready to be built up by connecting the following modules.

FIG. 8. A model of an example of a four-level module.

FIG. 9. An example of the execution of the components of a multi-level multi-chip module.

FIG. 10. Photo of an example of a multi-level multi-chip module.

Terms and Definitions

A circuit board is a structural element of a module in the form of a thin plate having electrical wiring for implementing circuitry solutions.

The horizontal electrical wiring of the board is a collection of thin (in the range from fractions to tens of micrometers) conductive lines and contact pads lying in one plane parallel to the board surfaces, forming a topological drawing that implements the commutations provided for by the circuit diagram.

Vertical electrical wiring - vertical electrical connections between pads located on opposite sides of the board.

Electronic components - enclosed and non-enclosed devices of semiconductor electronics, micro-electro-mechanical systems, piezoelectric and optoelectronic structures, as well as passive elements and other devices and electronic structures necessary for giving multichip modules the specified functional properties.

Installation - mechanical and electrical connection of two module elements in an arbitrary combination, for example, an electronic component and a circuit board, two circuit boards, a circuit board and a switching frame, as well as frames between each other. Electrical switching can be performed using metal (for example, gold) microwire, as well as without it, by directly connecting two contact pads during their application and subsequent soldering or welding, as well as using special conductive adhesives.

A circuit board is a circuit board that has only horizontal electrical wiring that implements the electrical circuitry for switching electronic components installed on its working surface, including the contour of contact pads for electronic components, as well as the circuit (s) of one-way output contact pads of a circuit board on its working surface along its perimeter . The circuit of the single-sided output contact pads of the circuit board is designed for its switching with the mating elements of the module design.

Patch board - a board that simultaneously has horizontal and vertical electrical wiring. The patch board is original if the horizontal electrical wiring of the patch board is determined by the nomenclature and / or electrical circuitry of the electronic components. The circuit board is unified if it can be used to directly or indirectly place on it a different range of electronic components with different electrical circuits for their connection. Vertical electrical wiring provides electrical communication in the two-sided circuit of the output contact pads between the corresponding contact pads on different sides of the circuit board.

A switching frame is a board with a large through window in its central part, which gives the frame geometry to such a board. In the body of the switching frame, a contour of bilateral contact pads is made in pairs electrically connected by vertical switching elements. The planar overall dimensions, as well as the dimensions in the axes of the two-sided circuits and the pitch of the contact pads for the switching frames and the switching boards are the same. In the nomenclature series, switching boards and frames are paired (conjugated) elements of a multilevel module.

Module level - an assembly as a part of a circuit board with electronic components, which are mounted on it directly or using a circuit board.

Multilevel multichip module - monolithic compounded vertical assembly of at least two module levels.

A detailed description of the positions of the drawings, the construction stages of the assembly of a multi-level multi-chip module

In FIG. 1 shows an example of four levels 1-4 of the construction of a multi-chip module 5 of this application. The installation of the levels of module 5 is performed using the switching frames 6. Each of the levels contains a switching board 7 with a window in its center and a mounting plate 8 with electronic components 9. The installation of electronic components 9 is performed on the mounting plate 8 without using wire. Mounting the mounting plate 8 with electronic components 9 on the switching board 7 is also performed without the use of wire mounting. The number of frames used for mounting two levels is different and is selected so as to form the minimum necessary height for the placement of electronic components 9. For example, the lower level 4 and the upper level 3 are interconnected by two switching frames, level 3 and level 2 are connected by one switching frame, level 2 and level 1 - two switching frames.

When assembling levels 1-4 into module 5, the levels are set through the switching frames 6 on top of each other. In this case, two options are possible: the frame is docked with the frame and the frame is docked with the patch board. Since the external contours of the electrical contacts of the switching frames and boards are the same, docking will occur in both cases, which provides an open module architecture and the possibility of building levels and, correspondingly, functions in it. For example, level 4 and 3 are connected along the external circuits of the electrical contacts of the circuit board and the switching frame, and level 1 and 2 are connected along the electrical contacts of the two switching frames with the external terminals 11 of the module as a whole.

Switching frames 6 can also be used to create a space for filling with compound 10, if such filling is allowed by the functioning conditions of electronic components of a given level, as is done, for example, in level 1. Switching frames can also be used as the base of module 5, as this done in level 4, ending with the switching frame 6.

The circuit board 8 is the only original element of the module (Fig. 2), has a horizontal electrical wiring, including electrically conductive lines 12 and the internal contours of the pads

13 for mounting electronic components, as well as the contour of the output contact pads 14, located along the perimeter of the board.

The circuit board 7 is unified (Fig. 3), is made with a through window 15 in its central part and has two contact pad contours: an external circuit of contact pads with an element of vertical electrical switching 16 and an internal circuit of one-way contact pads 17. In horizontal electrical wiring, the corresponding the pads are connected by electrically conductive tracks 18. The location and number of pads 17 is identical to the location and number of pads

14 of the mounting plate 8, which allows you to mount the mounting plate 8 on the circuit board 7 by imposing pads without using wire mounting.

The assembly of a multi-level multi-chip module is implemented, for example, in the following order. Electronic components 9 are mounted without using wire mounting on the mounting plate 8. The board (Fig. 4) has the corresponding internal contours of the contact pads 13 for mounting electronic components, as well as the output contact pads 14 with the connecting material (solder) applied to them 20. The mounting plate 8 (Fig. 5) with one or more electronic components 9 is mounted on the circuit board 7 by combining the external circuit of the contact pads 14 of the circuit board 8 with the internal circuit of the contact pads 17 the circuit board 7. The electronic components 9 are placed in the window 15 of the circuit board 7, using the volume of the window for partial or full placement of electronic components, which increases the density of installation in the module and reduces the required number of switching frames 6.

The switching frame 6 (Fig. 6) is made in the planar overall dimensions of the switching board 7, and the geometry of its circuit of the electrical contacts 19 with the elements of the vertical switching completely coincides with the geometry of the external circuit of the electrical contacts 16 with the elements of the vertical switching of the switching board 7. The thickness of all the switching frames, from the point of view of their unification, they can be the same or make up some limited nomenclature multiple row.

The patch plate 7 of the assembly level is supplemented with the required number of patch frames 6 (Fig. 7) from above and below, so that the circuit board 8 and electronic components 9, taking into account their partial immersion in the thickness of the patch plate, are inside the formed cavities. If necessary, such an assembly of levels with switching frames is completely or partially filled with compound 10.

The resulting assembly is mounted among themselves in a single module 5 (Fig. 1).

Patch boards and frames lie in one nomenclature row, which determines their planar dimensions and external contours of electrical contacts. They do not require changes with each change in the composition of electronic components to be assembled into a multilevel module and, therefore, relate to the unified elements of the module. The only original thing is the circuit board - a relatively simple module element that does not have vertical switching elements. The depth of the cavities for electronic components is determined by the number of commutation frames to be installed.

Thus, in the described design, all the tasks are solved and all the provisions of the claimed technical result are obtained, which are not achieved in the complex in any of the known analogues:

- high unification of the module components, allowing for optimal time and cost reconfiguration from series to series;

- the open architecture of the module, allowing to increase its design and functions without cardinal processing of its elements and layout as a whole;

- the possibility of using electronic devices of various types, technologies and sizes as electronic components and to create three-dimensional modules with high interspecific functionality;

- technical conditions for giving the module not only high functional, but also technical and operational parameters, for example, in the form of minimized RC delays and increased resistance to dynamic loads, due to the complete rejection of wire switching.

Execution example

As an example of the implementation of a multi-level multi-chip module according to this application, a four-level multi-chip module is assembled.

A computer simulation model of a four-level module is presented in Figure 8. The two lower levels contain a packaged impedance matching circuit 9.1, as well as a piezoelectronic product 9.2. In the upper two levels of the module, as electronic components 9, there are housingless semiconductor devices - the controller's crystal 9.3 and the specialized integrated circuit (IC) crystal 9.4.

Each level of the module has a switching board 7.1-7.4, a mounting board 8.1-8.4 with electronic components installed on it. Installation and electrical switching of the contact pads of the electronic components 9.1-9.4 with the contact pads of the horizontal electrical wiring of the circuit boards was made without the use of wire mounting. The installation of electronic components 9.1 and 9.2 is performed by the surface mounting method (in the English literature (SMD method). In this case, the option of two-sided installation of components on a circuit board is used. The installation of electronic components, which are products of silicon microelectronics 9.3 and 9.4, is performed from the front surface of silicon integrated circuits to a circuit board (in the English literature - the FlipChip method.) On the external contact pads of the circuit board previously applied the connecting material (solder) (Fig. 4 position 20).

The circuit board with the electronic components installed on it was turned over, the electronic components were immersed in the window of the circuit board and the contact pads of the external circuit of the circuit board and the internal circuit of the circuit board were combined. At a temperature of 240 ° C under a given pressure, the circuit board and the circuit board were switched. Figure 9a shows a photo of the assembly of the switching 7.4 and the mounting plate 8.4, on the lower side of which an IC chip is installed, and a switching frame 6.4 along the contour (Fig. 9b).

Patch board 7.4 and patch frame 6 are selected from the stock range of 20 × 20/64 unified patch boards and frames. They have the same planar overall dimensions of 20 × 20 mm, the same contours of bilateral electrical contacts (64 pcs.) With vertical switching elements. Elements of vertical switching are made in the form of through metallized holes.

Excessive size of the circuit board 7.4. with respect to the mounting plate 8.4, it is due to the fact that electronic components of large dimensions are installed in the lower levels. Meanwhile, patch boards of all levels have the same planar overall dimensions. In this regard, patch boards 7.1 and 7.2 from the same range of unified patch boards and frames 20 × 20/64 are selected from the second row of unification (unification by window size) and have large through-windows. Large mounting boards 8.1 (Fig. 9c) and 8.2 are mounted on them, since they are mounted larger than the IC 9.4 crystal, electronic components 9.1 and 9.2. In principle, the module circuit boards are selected only from the main unification series (overall dimensions and the number of vertical communication lines) or also from the secondary rows (through-window size, material, etc.), depending on which of the module's characteristics - technical or cost are dominant. When all the switching and, therefore, circuit boards in the module are in the main line of unification, the minimum cost of the module is achieved, but to the detriment of the technical parameters.

The dimensions of the through window in the patch board 7.3, 7.4 are 6.0 ×, 6.0 mm, and in the board 7.1, 7.2 the dimensions are 13.0 × 13.0 mm. The dimensions of the circuit board, respectively, for the two upper levels are 7.0 × 7.0 mm, for the two lower levels are 14.0 × 14.0 mm.

In FIG. 9c is a photo of the lower side of the assembled module. It can be seen that at the first lower level, the circuit board assembly with the circuit board is mounted in the module in an inverted state, by analogy with the module in FIG. 1 for the lower level 4. This is done to ensure the tightness of the module and possibly due to the identical topology of the connecting circuits, that is, the coincidence of the configuration of electronic contacts with vertical switching elements of any extreme parts of the assemblies being joined.

In FIG. 10 is a top view (FIG. 10a) and bottom (FIG. 10b) of the described assembly assembly, which has 64 output pads on its back side and is intended for further surface (SMD) mounting.

Tests have shown that the module is highly resistant to mechanical stress, for example, a single-impact shock with an overload of more than 20 thousand g, as well as reduced delays in comparison with other types of assembly of the same electrical circuit RC.

Depending on the operating conditions, the module can be optionally, as a product as a whole, filled with a compound or assembled in a rigid, for example, metal case.

Claims (12)

1. A multilevel multichip module containing at least two circuit boards, on the front side of which there are made electrical contacts connected by horizontal electrical switching with contact pads for electrical components, as well as containing electronic components installed on these contact pads; at least two patch boards with the same planar overall dimensions, along the outer perimeter of which electrical contacts with vertical electrical switching elements are made on the front and back sides, a through window is made in the central part, the size of which is smaller than the size of the mounting plate, electrical contacts are made along the window contour connected by horizontal electrical switching with electrical contacts with elements of vertical electrical switching, while the electrical contacts along the window contour are such that when a mounting plate is applied to the patch board, their electrical contacts coincide; switching frames of the same or multiple thicknesses with external dimensions matching the dimensions of the switching boards, with internal dimensions, larger dimensions of the circuit boards, along the external perimeter are made electrical contacts with vertical electrical switching elements, the arrangement of which coincides with the location of electrical contacts with vertical electrical switching elements boards, and when applying the switching framework and boards, the contacts are combined; wherein: the circuit board is installed on the circuit board with the combination of their electrical contacts so that the electronic components are located in the windows of the circuit boards, the switching frames are installed on the circuit boards with the combination of their electrical contacts with the elements of vertical electrical switching so that the circuit boards and electronic components are completely immersed in the windows framework. 2. A method of assembling a multi-level multi-chip module disclosed in paragraph 1, including: - installation of electronic components on circuit boards; - installation of circuit boards with electronic components on the circuit boards so that their electrical contacts are aligned; - selection of the required number of frames for each circuit board on the basis that the total thickness of the frames and the circuit board exceeds the maximum height of the electronic components located on the circuit board, while the total number of frames is minimal; - installation of the required number of switching frames on the circuit board so that the electrical contacts with the vertical switching elements of all the switching frames and the circuit board coincide with each other and form continuous lines of vertical electrical switching; - installation of the received assemblies on top of each other, each of which includes a circuit board with electronic components, a circuit board and the required number of frames so that the electronic contacts with the vertical switching elements of the extreme parts of the assemblies to be combined coincide with each other with the formation of a single multi-chip module. 3. The method according to p. 2, characterized in that the resulting assembly as part of a circuit board with electronic components, a circuit board and switching frames before assembly into the module is poured with a sealing compound.

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