JP2008244475A - Circuit cover assembly having aperture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an improved circuit structure. <P>SOLUTION: A cover assembly 10 is mounted on a substrate 14, has an internal face separated from the substrate 14, and fractionalizes a hollow chamber on a circuit assembly 12. Fluid can be charged into a chamber. The cover assembly 10 has an edge extending along the substrate 14 around a circuit assembly 12, and comprises a dielectric cover, an aperture which penetrates the dielectric cover, and a film extending across the aperture. The film is composed so that it allows gas to pass through the aperture, but prevents liquid from passing through. An electromagnetic shield 16 is attached to a dielectric cover and surrounds the hallow chamber. The aperture penetrates into the electromagnetic shield 16. The cover assembly 10 is mounted onto the dielectric cover and includes a conductive assembly 39 electrically connected to the circuit assembly 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  This application claims priority to US patent application Ser. No. 11 / 692,129, filed Mar. 27, 2007.

  The electronic circuit component may be covered by a housing or cover to protect the circuit component or to suppress dangerous or destructive electromagnetic (EM) radiation caused by the electronic circuit component at communication frequencies including radio frequencies. . In many cases, the cover is electrically conductive and can be connected to circuit ground. The EM shield may be a solid metal housing or lid shaped to form a chamber surrounding the electronic circuit. EM shields have been developed for use in a dense electronic environment that includes a large number of electronic components on a substrate. Such circuit components may be used in environments where significant temperature and / or pressure changes may exist, or may be affected by weather or ambient contaminants.

  The cover assembly can be mounted on the substrate. The cover assembly may have an inner surface spaced from the substrate and may define a hollow chamber on the circuit assembly. The hollow chamber may be filled with a fluid, such as a gas or a liquid. The cover assembly may have an edge that extends along a substrate around the circuit assembly. In certain embodiments, the cover assembly may include a dielectric cover, an opening extending through the dielectric cover, and a film extending across the opening. The dielectric cover may substantially surround the (delimited) hollow chamber defined by the dielectric cover. The opening may provide fluid communication between the hollow chamber and the exterior of the dielectric cover. The membrane may be configured to allow one or more gas species to pass through the opening and prevent liquid from passing through the opening. In certain embodiments, an electromagnetic shield may be attached to the dielectric cover, and the electromagnetic shield may substantially surround the hollow chamber. The opening may extend through the electromagnetic shield. The cover assembly may include a conductive assembly attached to the dielectric cover and electrically connected to the circuit assembly.

  FIGS. 1-4 show a simplified schematic of a representative circuit structure 8 that includes a cover assembly 10, ie, a cover having various features, shown for convenience with a single composite embodiment. These features may have a variety of configurations and can be implemented separately in other cover assemblies or in various other combinations. As used in this embodiment, the cover assembly may comprise one or more complete circuits, one or more portions of one or more circuits, one or more combinations of circuit elements or components, or circuits, Any combination of circuit portions and circuit components can accommodate one or more circuit assemblies 12 that can be formed individually or jointly and that can include shared circuit portions or components.

  In this example, therefore, the cover assembly 10 can be mounted to the substrate 14. Cover assembly 10 is also referred to as an enclosure. If it is desired to shield electromagnetic radiation, the cover assembly 10 may include an electromagnetically conductive layer that forms the EM shield 16. The cover assembly 10 has a top or distal surface 20 and an intermediate surface 22 such as side surfaces 22a, 22b, 22c and 22d that form a sealed hollow chamber 26. The hollow chamber may be filled with a fluid, such as a gas or a liquid. When filled with a highly insulating liquid, the reliability of the sealed circuit will be improved. Examples of such liquids include gamma butyrolactone, N-methyl-2-pyrrolidine, hydrofluorocarbons or fluorocarbons, fluorocarbons, polychlorobiphenyls, (general) transformer oils, mineral oils (many grades exist) and silicone oils Etc. As can be seen from the cross-sectional view of FIG. 2, the cover assembly may be a laminate, i.e., may be composed of multiple layers. The conductive or outer layer 16 may extend along the entire outer surface of the cover assembly. The shield 16 may be formed of an electromagnetic (including electrical or magnetic) conductive material, such as aluminum, copper, or other material, and may be made of a non-conductive (dielectric) or semiconductive material. It may be formed from a combination of materials such as a conductive layer provided (at least one of which has conductivity). A dielectric layer or dielectric 17 may be present immediately adjacent to the shield 16. The dielectric 17 may be a composite layer further disposed in one or more layers.

  The shield 16 may also include one or more openings or notches, such as notches 24, so that current (eg, in the form of signals or power) can be passed to the chamber without compromising the shielding function. It is possible to flow into or out of 26. Although only one cutout is shown in this example, the EM shield may include one or more cutouts, and that such cutouts can be placed on the top or side of the cover assembly 10. I want you to understand. As is apparent from the figure, conductor 33 (shown mounted on substrate 14) electrically connects circuit assembly 12 to another circuit assembly or component located outside the cover assembly. Can pass through the notch 24. The conductor 33 may be an electric wire, a microstrip line, or any other form capable of passing a current.

  Cover assembly 10 may protect a circuit assembly, such as assembly 12, for example, contained within chamber 26 from environmental as well as electromagnetic effects and / or isolate a sealed circuit assembly. Although not shown, the cover assembly 10 may further include an inner wall that can separate the chamber 26 into one or more sub-chambers that may be capable of isolating two or more circuit assemblies.

  The circuit assembly 12 may include various components. For illustration purposes, the circuit assembly 12 may include individual circuit elements 30 and 32 connected by suitable interconnections, for example, by connecting wires 34. The connecting wire 34 may be connected to the circuit element 30 by connection to a terminal 31 arranged on the circuit element. The circuit element 30 may include lumped or distributed elements, i.e. passive and / or active elements such as combinations or networks of transmission lines, resistors, inductors and semiconductor devices, etc., and a dielectric substrate, It may be mounted on a circuit chip having a semiconductor substrate or a conductive substrate. In addition, the circuit assembly 12 includes one or a combination of diodes or transistors in an integrated circuit (IC) or chip including, for example, a monolithic microwave integrated circuit (MMIC), an application specific integrated circuit (ASIC), and the like. May be. For purposes of illustration, circuit element 32 may be a conductor for transmitting a signal or power to circuit element 30.

  As can be seen from FIG. 2, the EM shield 16 may be attached directly to the substrate 14 at one or more points. In this example, the substrate 14 is conductive and provides a ground for shielding. Other forms of substrates can be used, for example dielectrics with one or more conductive layers. Accordingly, the shield 16 can be directly attached to the substrate 14 using the conductive adhesive 36. The conductive adhesive may include a conductive epoxy resin, conductive pad, solder, brazing material, deformed metal, z-axis conductive elastomer, or similar conductive or resistive material. Further, a plurality of types of conductive adhesives may be used for attaching the cover assembly 10. Note that the face 22c of the cover assembly may not be attached directly to the substrate 14 in the region of the notch 24.

  Optionally, the EM shield 16 may include one or more electrical ground connectors (not shown) for grounding the shield 16 to a local circuit ground. This ground connector may be in the form of a metal strip that extends from one or more parts of the shield, into the substrate, into an adjacent EM shield, or whatever ground connection is available. Good.

  The conductors 32 and 33 can be mounted on the substrate 14 using the insulating layer 38. The insulating layer may be in the form of an insulating epoxy resin or other adhesive, or an insulating pad. These insulating layers insulate the conductor from the conductive substrate. The circuit element 30 of the circuit assembly 12 may require that it be grounded, in which case the back surface of the circuit element 30 may be attached to the substrate 14 using a conductive adhesive 36.

  Cover assembly 10 may further include a conductive assembly 39 supported by dielectric 17 relative to shield 16. The conductive assembly 39 can provide a continuous electrical path 41 through or along the cover assembly. Path 41 may have branches and multiple paths, whether configured to carry signals or configured to carry power. The components of the conductive assembly may extend along the surface of the dielectric 17 or may be embedded therein. The dielectric 17 may be a single dielectric layer or a composite layer formed of a plurality of dielectric layers, and these layers are separated by layers of one or more non-dielectric materials. It may or may not be. In this example, the dielectric 17 includes a first dielectric layer 42 and a second dielectric layer 46. The first and second dielectric layers 42 and 46 are continuous along the EM shield 16 and may extend along the top surface 20 and side surfaces 22a, 22b, 22c and 22d of the cover assembly. The dielectric 17 may also extend only over one or more portions of the shield 16. In certain regions, the first and second dielectric layers 42 and 46 may change to a single layer that is not separated by a non-dielectric material. The second dielectric layer 46 may have an inner or inner surface 48 that defines the chamber 26. The dielectric layers 42 and 46 are shown to extend from end to end and down the sides of the top surface of the cover assembly, but may be separate, for example, to form part of the dielectric that comprises the sides. A body dielectric layer can also be used.

  The conductive assembly 39 may include a conductive strip 44 that can extend through or over the dielectric layer 17. In the illustrated form, the conductive strip 44 is sandwiched between the first dielectric layer 42 and the second dielectric layer 46. The conductive strip 44 can be formed from a suitable conductive material including the conductive metal described above.

  The intermediate sides 22a and 22c of the cover assembly may include one or more vias 50, such as vias 50a and 50c, extending between the first and second dielectric layers 42 and 46. The vias can be formed by drilling, etching, or otherwise creating individual elongated via holes 52, such as holes 52a and 52c. Such via holes or tunnels may extend between the first and second dielectric layers 42 and 46, or may extend through separate layers. These via holes are then covered with an electromagnetically conductive material or partially or completely filled with an electromagnetically conductive material to form a via.

  Vias 50a and 50c may extend across the entire height of side surfaces 22a and 22c as shown. The cover assembly 10 may have a lower edge 54 that contacts the substrate 14. Vias 50a and 50c thus have a lower end or portion located near the lower edges 54a and 54c of the cover assembly, and an upper portion that abuts the conductive strip 44 at the respective intersection points 56a and 56c. It extends to. The lower end of the via can be connected to the signal conductors 32 and 33, respectively, by suitable means such as using a conductive adhesive 36, for example.

  Vias 50 a and 50 c can be connected to the conductive strip 44 to form a conductive assembly 39 within the cover assembly 10. The conductive assembly 39 may be usable as part of a circuit. For example, the conductive layer 33 may be capable of carrying a current or signal that is used or generated by the circuit element 30 of the circuit assembly 12. The current can be transmitted from the circuit element 30 via the terminal 31, the connecting wire 34, the signal conductor 32, the via 50 a, the conductive strip 44, the via 50 c and the conductor 33. Thus, via the conductor 33, signal or power can travel between the circuit assembly 12 and circuitry outside the shielded chamber 26.

  Shown in FIGS. 1-4 is an embodiment of a cover assembly that includes only one conductive strip 44 embedded in the cover assembly 10 and connected to vias 52a and 52c at intersection points 56a and 56c, respectively. The cover assembly 10 may include one or more conductive strips or conductive assemblies that may be further embedded between two or more separate dielectric layers, or on a dielectric layer or dielectric. It may extend to. Similarly, although FIGS. 1-4 show vias formed on two sides of the cover assembly, such vias may be included on all or some combination of sides of the cover assembly. In some embodiments, one or more conductive strips may be included along side 22 instead of or in addition to vias. Furthermore, a large number of vias and / or a large number of conductive strips may be present on any one side. Other forms or structures can be used to implement the conductive assembly 39.

  Cover assembly 10 may include a portion of resistive material 60 that may be effective in attenuating undesirable electrical propagation within chamber 26. An enclosure such as chamber 26 may involve resonances at various frequencies that may prevent proper operation of circuit assembly 12 within chamber 26. Resistive material 60 can reduce such resonance, i.e. attenuate such resonance, and the layer of resistive material 60 may extend along all or a portion of dielectric layer 46.

  The resistive material 60 may be a layer of resistive ink, film, paint, other resistive coating, or a combination thereof. This material can be provided by silk screening, screen printing, spraying, jetting, painting, ink jet printing, lithography, offset printing, or any other convenient technique. Optionally, the resistive material 60 can be provided discontinuously according to a distribution pattern to form multiple regions of resistive material.

  As shown in FIG. 2, the inner cover assembly surface 48 is a first resistive material region 62 that is uniform and covers a portion of the inner cover assembly surface along both the top surface 20 and the side surface 22a of the cover assembly 10. May be included. The inner surface may also include a second resistive material region 64 that covers only a portion of the side surface 22c. The resistive material may have a uniform thickness and the thickness may not be uniform. A region with a resistive material can be connected to the substrate 14 using a conductive adhesive 36.

  An alternative embodiment is shown in FIG. As can be seen from this cross-sectional view, the inner cover assembly surface may be covered by a uniformly patterned resistive material 60. Such a pattern 70 may have a predetermined ratio of open insulating regions 66 to coated resistive material regions 68. The resistive material pattern 70 may be provided on a sheet or film that may include a mesh. Such films can be defined as having an average resistivity of 10 ohms / square to 1000 ohms / square.

  Another embodiment is shown in FIG. As can be seen from this cross-sectional view, the resistive material 60 is disposed in the second dielectric 17. The dielectric 17 can be formed in multiple stages or layers, for example, by forming the first and second dielectric layers 42 and 46. The resistive material can be applied to the intermediate surface by silk screening, screen printing, spraying, jetting, painting, ink jet printing, lithography, offset printing, or any other convenient technique. The resistive material 60 can be provided discontinuously according to a certain distribution pattern in order to form a large number of regions made of a resistive material, such as the pattern shown in FIG. In that case, the resistive material 60 may be entirely on the inner surface of the cover assembly, completely within the cover assembly, or partially within the cover assembly, and partially It should be understood that it may be present on the surface of the cover assembly.

  As noted above, the addition of such a layer of resistive material will result in resonance in the chamber 26 as well as attenuation of external coupling over the desired frequency range. To improve this attenuation, the resistive material 60 can be selected depending on the resistivity and the thickness and pattern in which the material is provided. Further, attenuation can be improved by appropriate selection of the dielectric material included in the first and second dielectric layers 42 and 46 of the cover assembly 10 and the thickness of the dielectric material.

  The cover assembly 10 can be manufactured from circuit board material, including conductive and dielectric materials. The circuit structure 8 including the cover assembly 10 and / or the substrate 14 or related circuitry such as the cover assembly 10, the substrate 14 and the circuit assembly 12 can be implemented with an article disposed on the panel. Therefore, after large-scale production on the panel, an operation for dividing the assembly into individual pieces can be performed.

  Such an assembly operation will result in a number of circuit assemblies 12 in each chamber 26 and a number of chambers 26 in each cover assembly 10. Further, a given cover assembly may include material 60 for damping or it may be omitted, may include conductive assembly 39, or it may be omitted, and The EM shield 16 may be included or omitted.

  Also shown in FIG. 5 is a conductive element 50a in place of via 50a, partially disposed on inner surface 48 of cover assembly 10 and partially through dielectric layer 46. A portion of the conductive element 50a on the inner surface can be provided using techniques similar to those used to provide the resistive layer. A portion of the conductive element 50a extending within the dielectric layer 46 may be in the form of a via. Therefore, it should be understood that the conductive assembly 39 can be partially or fully disposed on the inner or outer surface of the cover assembly as long as it is electrically isolated from the electromagnetic shield 16.

  The hollow chamber 26 can be filled with, ie contain, a gaseous substance. In one example, one or more gas species may be generated from a material such as an adhesive, ink, etc., or may be generated in the hollow chamber in another manner. To maintain the integrity of the cover assembly, the assembly may include one or more openings 80 extending between the hollow chamber and the exterior of the cover assembly, as shown in FIGS. Good. This opening may be occluded, i.e. covered by a membrane 82. In some embodiments, the membrane may allow one or more gas species to travel between the hollow chamber and the exterior of the cover assembly. In addition or alternatively, the membrane may prevent liquid from going back and forth between the hollow chamber and the exterior of the cover assembly.

  In FIG. 6, the top or distal surface 20 and side 22a each include an opening 80 that extends through a cover assembly that includes an electromagnetic shield 16 and a dielectric 17. The gas permeable membrane 82 may extend across the opening, for example, by being attached to the inner surface 48 so as to cover the opening. As indicated by the dashed line in FIG. 6, the membrane may optionally be attached to the outer surface 84 so as to cover the opening.

  In FIG. 7, the top or distal surface 20 and the side surface 22a generally extend from a first dielectric layer 86 and a second dielectric layer 88 that surround, or embed, at least a portion of the membranes 82 ′ and 82 ″. Is formed. Opening 80 ′ formed in side surface 22 a includes opening portion 90 extending through first dielectric layer 86, second dielectric layer 88, and electromagnetic (if it is included in the cover assembly). And an opening 92 extending through the shield 16. As can be seen in FIG. 7, the opening portions 90 and 92 of the opening 80 'are generally aligned with each other and the uniform opening 80' extending through the cover assembly between the inner and outer surfaces of the cover assembly. Form a part of The membrane 82 'allows one or more gas species to flow directly out of the hollow chamber via this membrane 82' extending to every corner of the opening 80 '.

  Optionally, the film may extend completely beyond the boundaries of one or more dielectric layer openings, as indicated by the opening film 82 '' in FIG. In some embodiments, membrane 82 '' may extend to one of the surfaces of the cover assembly, such as outer surface 84. In such an embodiment, one or more gas species can enter the membrane, for example, at the inner opening portion, and the opening 80 '' extended to an exposed portion 94 (one or more gas species are released at this location). 'Can move along the membrane.

  In another embodiment, the outer second opening portion 92 ′ can be located proximal to the first opening portion 90 ′ but is partially or completely misaligned with the first opening portion 90 ′. It may be in a state, that is, an offset state. In one embodiment, the opening portions 90 ′ and 92 ′ of the opening 80 ″ are completely offset as shown in FIG. 7 (the opening portion 90 ′ is also partly between the surfaces of the cover assembly). Not aligned with the opening portion 92 'of the extending opening 80' '). In such an embodiment, one or more gas species penetrate the membrane at the first opening portion 90 'and move along the opening portion including the membrane between the opening portion 90' and the opening portion 92 '. , And can enter the opening 92 ′.

  In another embodiment, the open portion may extend only partially through the cover assembly, eg, from one face to a channel or flow path that includes the membrane. Thus, in some embodiments, there may be only an opening portion 90 ′ or an opening portion 92 ′, but not both, and the membrane is further open to the surface of the cover assembly, as in the opening 80 ′ ″. Extending along the part.

  Membrane 82 may be any suitable material having gas permeability and / or liquid repellency, such as polytetrafluoroethylene sold under the trade name GORE-TEX® from WL Gore & Associates of Newark, Newark. It can be formed from a porous polymer such as (ePTFE) and / or a fluoropolymer film, a metal foil such as a palladium foil, and the like. The membrane may allow all gas species to pass evenly, or a species with a small molecular weight, such as a certain gas species, eg hydrogen gas, is larger than water vapor. It may be able to pass more easily than a species with a molecular weight. In some embodiments, the membrane may be conductive or may include a conductive portion connected to the electromagnetic shield 16 or conductive assembly.

  Optionally, a plug (not shown) comprising a membrane can be removably inserted into the opening using a screw or similar retaining mechanism. For example, as is well known, a plug having such a gas permeable material that covers a channel that penetrates the plug allows microwave ventilation to allow ventilation of the housing while preventing rainwater or surrounding contaminants from entering. Used in housings for outdoor units that house machines. This type of membrane vent plug is available from W. L. Gore & Associates.

  Although the embodiment of the circuit structure has been illustrated and described in detail as described above, various modifications can be made. Other combinations and partial combinations of features, functions, elements and / or properties may be utilized. Such variations are also (different, wider, narrower, or equal, regardless of whether they are intended for different combinations or for the same combination. Whether or not) is considered to be covered by the subject matter herein. The above embodiments are exemplary, and no single feature or element is essential to every possible combination that may be claimed for this or a later application. Accordingly, the claims are intended to define the invention disclosed herein. With respect to an “an” or “first” element or equivalent phrase in a claim, this means including one or more such elements, and two or more such elements are required Neither does it exclude the existence of two or more such elements. In addition, indications indicating the order of the distinct elements, such as first, second or third, are used to distinguish between these elements and suggest a necessary or limited number of such elements Rather, it does not imply a particular position or order for such elements unless specifically stated.

It is a top view of the circuit structure containing the cover assembly mounted on the board | substrate. FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. FIG. 3 is a partial cross-sectional view similar to FIG. 2 for another example of a cover assembly. FIG. 3 is a partial cross-sectional view similar to FIG. 2 for another example of a cover assembly. FIG. 3 is a partial cross-sectional view similar to FIG. 2 for another example of a cover assembly.

Explanation of symbols

8 Circuit structure 10 Cover assembly 12 Circuit assembly 14 Substrate 16 EM shield (electromagnetic shield)
17 Dielectric layer (dielectric)
20 Upper surface (distal surface)
22 Intermediate surface 22a-22d Side surface 24 Notch 26 Sealed hollow chamber 30, 32 Circuit element 31 Terminal 33 Conductor 34 Connection wire 36 Conductive adhesive 38 Insulating layer 39 Conductive assembly 41 Electrical path 42 First dielectric layer 44 Conductive strip 46 Second dielectric layer 48 Inner cover assembly surface (inner surface)
50 Via 52 Via hole 54 Lower edge 56a, 56c Intersection point 60 Resistive material 62 First resistive material region 64 Second resistive material region 66 Opened insulating region 68 Covered resistive material region 70 Pattern 80, 80 ′, 80 ″, 80 ′ ″ Opening 82, 82 ′, 82 ″ Film 84 Outer surface 86 First dielectric layer 88 Second dielectric layer 90 Opening portion 90 ′ First opening portion 92 Opening Part 92 ′ Second opening part 94 Exposed part

Claims (10)

A circuit structure,
A substrate,
A circuit assembly provided on the substrate;
A cover assembly disposed on the substrate and defining a hollow chamber and having an inner surface spaced from the substrate and the circuit assembly;
The cover assembly includes an edge extending along the substrate around the circuit assembly, an opening extending through the cover assembly including a dielectric cover, and a film extending across the opening. And having
The opening provides fluid communication between the hollow chamber and the exterior of the cover assembly, and the membrane allows one or more gas species to pass through the opening and liquid passes through the opening. A circuit structure configured to prevent this.   The circuit structure according to claim 1, wherein the film is adhered to an inner surface of the dielectric cover so as to cover the opening.   The circuit structure according to claim 1, wherein the film is adhered to an outer surface of the dielectric cover so as to cover the opening. The dielectric cover comprises a first dielectric layer proximal to the hollow chamber and a second dielectric layer distal to the hollow chamber;
The opening comprises a first opening portion extending through the first dielectric layer, and a second opening portion extending through the second dielectric layer;
The circuit structure according to claim 1, wherein the film is disposed between the first dielectric layer and the second dielectric layer.   5. The circuit structure according to claim 4, wherein the first opening portion and the second opening portion are aligned when viewed from the inner surface of the cover assembly.   The first opening portion and the second opening portion are at least partially misaligned when viewed from the inner surface of the cover assembly, and the membrane is in contact with the first opening portion. The circuit structure according to claim 5, wherein the circuit structure extends between the second opening portion.   The membrane is at least partially disposed within the dielectric cover and extends to a surface of the cover assembly, and the opening extends at least partially along the membrane. The circuit structure according to claim 1.   The circuit structure according to claim 1, wherein the cover assembly has a distal surface facing the substrate, and the opening extends through the distal surface.   The cover assembly has a distal surface facing the substrate and an intermediate surface extending between the distal surface and the substrate, and the opening extends through one of the intermediate surfaces. The circuit structure according to claim 1, wherein the circuit structure is present.   The cover assembly includes an electromagnetic shield attached to the dielectric cover and substantially surrounding the chamber, the opening extending through the electromagnetic shield. The circuit structure according to claim 1.

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