Abstract: An integral semiconductor package and mounting structure in which a lid for sealing a semiconductor chip on a platform includes flanges extending beyond the platform with the flanges having holes for receiving screws for mounting the package to a heat sink. The flanges are flexed into engagement with a heat sink thereby maintaining the package in yieldable pressure engagement with the heat sink.

Abstract: Heat sinks and methods particularly suited for use on packaged integrated circuits which are not amenable to the use of snap-on heat sinks and on which cemented-on heat sinks prevent conventional probing or reworking of the integrated circuit in the event trouble-shooting of the circuit is required after mounting of the heat sink. In accordance with the invention, a scalable post, based on heat sink size, mass and integrated circuit size, is cemented to the integrated circuit package in a configuration and location not interfering with the later probing or reworking of the integrated circuit, and without interfering with the printed circuit board layout. The post is then used to removably and independently hold a heat sink onto the integrated circuit so that good heat transfer between the integrated circuit and the heat sink is achieved, but still allowing the removal of the heat sink at any time if probing of the integrated circuit is later required. Alternate embodiments are disclosed.

Abstract: A ceramic package and mounting structure which requires less surface area on a heat sink and improves heat transfer to the heat sink. Each ceramic package has a top side and a bottom side with the bottom side being flat and smooth. The bottom side can be a polished ceramic, or metal layer which is plated or brazed to the bottom side. The mounting structure includes a clamp and a spring in pressure engagement with the top side of the package for maintaining the package in pressure engagement with the heat sink.

Abstract: The replaceable power module includes a power section positioned between a cover and a frame. The cover is provided with clips to permit the attachment and detachment of the cover to the base as well the attachment and detachment of the power module to a surface mounted integrated circuit. The frame is provided with an opening for receiving the integrated circuit, and electrical contacts for electrically connecting the power module to the leads of an integrated circuit. The power section is electrically coupled to the frame and includes a battery and a crystal oscillator for controlling the integrated circuit.

Abstract: A method and apparatus for simultaneously coupling a heat sink to an electrical device and reducing electromagnetic interference caused by the heat sink being coupled to the electrical device. A mother board, as used in an electronic circuit, is situated so that an electrical pad is located proximate to a socket for receiving the electrical device. The electrical device is placed inside the socket, and further has the heat sink thermally coupled to a top surface thereof. The heat sink serves to dissipate any heat radiating from the electrical device into a surrounding air mass. A heat sink clip physically and electrically engages with the heat sink and physically engages with the socket, thereby securing the heat sink to the device and the device to the socket. The heat sink clip also includes a tab that, when the clip is engaged with the heat sink, is in electrical contact with the pad, which in turn is in contact with a ground power supply.

Abstract: An apparatus for integrating wafer scale semiconductor integrated circuits and interfacing them with other systems. A wafer, partial wafer, die or plurality of same are mated to a printed circuit board (PCB) which electrically contacts the pads on each die using small conductive pillars. The PCB in turn is connected easily to other electronic systems. The entire apparatus is incorporated into other systems which utilize the dice in the apparatus. The apparatus may be fitted with heating elements and cooling channels to generate the necessary dice temperatures for burn-in, testing, and operation. The apparatus is easily adaptable to include more dice in a stacked configuration.

Abstract: A technique for applying uniform force to an IC chip module, urging the module into electrical contact with one face of a circuit board, is provided. One face of the board has contact pads, and the module has contact members on one surface corresponding to the contact pads. A first clamping member is provided having a pressure applying section and a reaction section mounted for movement toward and away from each other. A second clamping member having a pressure applying section is provided. The module is interposed between the pressure applying element of one of the clamping members and the substrate with the contact members on the module in electrical contact with the pads on the board. Several pins interconnect the reaction section of the first clamping member and the second clamping member to restrain movement of the reaction section of the first clamping member away from the second clamping member.

Abstract: A compression bonded type semiconductor element having a ring-shaped gate terminal in the form of an annular metal disk projecting through the side of an insulating cylinder. The ring-shaped gate terminal includes an inner circumferential planar portion which is disposed so as to be slidable on an annular ring gate electrode. The annular ring gate electrode is in contact with a gate electrode formed on a semiconductor substrate, and the ring gate electrode is pressed against the gate electrode via the ring-shaped gate terminal by an elastic body.

Abstract: A spring clamp device providing a compressive stress to a stack of components includes a spring member and a bracket having attachment structure for engaging mating structure near the bottom of the stack. The bracket is first engaged with the mating structure such that it straddles the stack. The spring member is then latched to the bracket under tension in an assembled configuration, thereby applying an upward reaction on the mating structure with the attachment structure of the bracket and applying a downward reaction force to the top of the stack with the spring member. The oppositely directed forces apply a compressive stress to the stack, which improves thermal contact between the components.

Abstract: An encapsulated electronic part has a resin body and a projecting holding member removably attached to the resin body which may be made of the same resin and formed at the same time as the resin body. The encapsulated electronic part may be conveyed to a test device or to a circuit board and mounted thereon by gripping the holding member with a holding device. The holding member may have a shape conforming to the shape of the holding device and may be separated from the resin body by moving the holding device while holding the resin body stationary.

Abstract: Latches are pivotally provided on opposite sides of an IC device stored in the pocked of an IC carrier. Connecting arms of the latches are engaged in engagement holes formed in actuator members which are biased upwardly by springs. The top surface of the IC carrier, except the IC pocket, is covered by an actuating plate. The positioning pins of an IC set/removal mechanism are inserted into holes of the IC carrier so as to cause the mounting plate to which the pins are secured to press the actuating plate down against the top face of the IC carrier causing the actuator members to pivot the latches, whereby the hold-down lugs of the latches are retracted from the top of the IC. The IC is now ready to be picked up by a suction pad.

Abstract: A block-shaped IC module (1) seals an IC chip (30) by an insulator and comprises contact terminals (101 to 106; 111 to 116) and retaining means (14, 15), wherein the contact terminals (101 to 106; 111 to 116) extend from an upper surface to side surfaces of the IC module (1) and they are electrically connected to the IC chip (30) so as to send data to or receive data from the IC chip (30). A data carrier (100, 120, 140, 160) on which the IC module (1) is fitted includes a hole portion (41, 91) having holding members (42, 43; 71, 72; 92, 93) corresponding to the retaining means (14, 15) so as to be engaged with the IC module (1). Accordingly, one IC module (1) can be freely used for various data carriers. Further, the IC module (1) can be thickened as much as possible, thereby improving strength of the IC module (1).

Abstract: A spring clip assembly having integral backbone with a plurality of the spring clip members extending from the backbone, each spring clip member having a tapered loop. The loop tapers to an inwardly facing end. If desired, a special insertion tool can be used to provide for a zero insertion force assembly.

Abstract: The present invention concerns an electronic power module comprising several integrated power circuits which may, for example, be insulated gate bipolar transistors (IGBT).

Abstract: A highly dense electronic module for installation into a computer or other electronic device comprises at least one wafer or wafer section and means for connection with the electronic device. With an embodiment comprising plural wafer sections, the wafer sections are mechanically joined and electrically coupled.

Abstract: A power semiconductor module is specified in which at least one semiconductor chip, which is fitted on a baseplate, is made contact with by a respective contact plunger. The position of the contact plungers can be set individually in a manner corresponding to a distance between the semiconductor chips and a main connection which accommodates the contact plungers. The contact plungers are either subjected to pressure by means of a spring or fixed by means of a solder layer.

Abstract: A semiconductor device socket preventing adhesion of foreign material to mounting surfaces of external leads of a semiconductor device. In the semiconductor device socket, a positioning base supports a shoulder of each of external leads extending from the semiconductor device without contacting the base and the contact portion of each of the movable contact terminals makes electrical contact with the shoulder of the corresponding external lead. The movable contact terminals are disposed opposite to the external leads outside of the positioning base and are opened and closed as a movable cover is moved relative to the base.

Abstract: An apparatus for integrating wafer scale semiconductor integrated circuits and interfacing them with other systems. A wafer, partial wafer, die or plurality of same are mated to a printed circuit board (PCB) which electrically contacts the pads on each die using small conductive pillars. The PCB in turn is connected easily to other electronic systems. The entire apparatus is incorporated into other systems which utilize the dice in the apparatus. The apparatus may be fitted with heating elements and cooling channels to generate the necessary dice temperatures for burn-in, testing, and operation. The apparatus is easily adaptable to include more dice in a stacked configuration.

Abstract: An integrated-circuit interconnect which can be formed at the wafer level is achieved by depositing an intentionally stressed contact layer over a release layer which is subsequently removed. The removal of the release layer permits a portion of the contact layer to curve away from the surface of an integrated chip. The result is a spring contact having a base portion joined to a member of the chip and a spring portion which is available for joining of other metal members, e.g., on a substrate or another chip. The resilience of the spring portion can also be used to position and align integrated circuit elements.

Abstract: A substrate, an alignment plate, a heat sink, a back plate, a plurality of spacers, and a plurality of nuts are used to removably package one or more semiconductor package into a single module. The semiconductor dies are packaged with tape automated bonding (TAB) packages having land grid array (LGA) outer lead bumps. The substrate comprises a number of land patterns, a number of alignment cavities, and a number of join cavities. The alignment plate is fabricated with a number of alignment pins, a number of housing cavities, and a number of join cavities. The heat sink is fabricated with a number of stems and a number of join cavities. The back plate is fabricated with a number of extrusions having threaded ends. The spacers are fabricated with flanged openings at both ends, and each spacer is loaded with a number of spring washers. The nuts are fabricated with stepped heads.

Abstract: A fin assembly for dissipating heat generated by an integrated circuit chip mounted on a socket having a pair of positioning ears disposed at two opposite sides thereof is disclosed. The fin assembly includes a fin and a pair of substantially L-shaped fastening members. The fin includes a bottom surface for contacting an integrated circuit chip and an upper surface from which a plurality of ridges extend upward along a length direction thereof. Each two adjacent said ridges define a channel therebetween and in one of the channels, at least one of two associated adjacent ridges has one extension extending toward the other ridge thereby defining a compartment having two opposite ends. Each of the fastening members comprises a first limb and a second limb. The first limb has a springing section formed adjacent to a joint of the first and second limbs and a flexible biasing section projecting from a free end thereof and extending toward said second limb.

Abstract: A clamping system is provided for effectively securing at least one power device in a thermally-conductive and electrically-insulative manner to a heatsink with a clamp member having an elongated member portion adapted to bear against a device, and a second member portion having an end adapted to bear against a heatsink. A fastener exerts a force on the member between the device and the second member portion to force an end of the second member portion into contact with the heatsink, and cause the member portion overlying the device to reciprocally exert a pressure on the device against the heatsink.

Abstract: In a semiconductor package comprising a heat spreader, a heat sink, a wiring board, and a connector, a heat spreader mounted on a remaining region of the upper surface of a substrate. The heat sink is thermally connected to a primary integrated circuit chip through the heat spreader and to a secondary integrated circuit chip. The heat sink has electrical conductivity. The heat sink comprises a base plate and at least one connecting member which perpendicularly extends from the base plate. A wiring board has a plurality of contact holes and a plurality of contact slits. A connector is mounted on the wiring board. The connector has a plurality of contacts. The contacts comprises a plurality of socket portions and a plurality of terminal portions. The contacts are connected to an input/output pins with the input/output pins inserted into the respective socket portions. The terminal portions are inserted into the respective contact holes. The connector has at least one ground contact.

Abstract: There is disclosed a cover for protecting the leads extending between a silicon chip device and an associated printed circuit board and their electrical connections with the board. The cover is formed out of clear plastic allowing inspection of the chip device and has several legs for securing and maintaining the cover on the board and has openings that allow for cooling of the chip device.

Abstract: A peripheral card includes a two-part metal cover mounting a printed wiring board on a U-shaped plastic frame. The wiring board is spaced from inside surfaces of the cover preferably by a pair spring clips mountable on side edges of the wiring board, each clip having an apertured intermediate bight portion overlying and in aperture burr scraped contact with ground contact pads on the board. Barbed-end spring fingers extend integrally from the bight portion preferably toward the board side edge to which it affixed and into scraped contact with respective ones of the metal cover parts as the metal cover parts are assembled together. The clips hold the board from movement in the cover and electrically ground any static electrical charges on the metal cover parts to the contact pads and to a ground socket in the frame, and electrically ground the metal cover parts to provide electromagnetic shielding of the electrical circuitry on the wiring board.

Abstract: The invention relates to an arrangement for a preassembled structure of disc cell semiconductors that can be pressure-contacted, in which a loose, stacked module comprising disc cell semiconductors, associated terminal tags and end-side cooling cells and insulating cells is held together until final assembly by means of loose fixation via insulating pipes that serve to insulate the studs to be brought in later for pressure-fixation of the module, for which purpose the insulating pipes, each being provided at one end with a flange, engage a common holding plate from behind, and are guided at the other end through a common insulator, via which axial securing of the module is effected through frictional-lockup connection to the insulating pipes by means of a tightening strap.

Abstract: The present invention provides a semiconductor integrated circuit apparatus with a heat sink that can be changed in size, that accommodates a board and electronic parts having different sizes, and that increases heat radiation. The present invention includes a cooling member facing and connected to electronic parts via a thermally conductive resin or thermally conductive fat and fatty oil and at least two thermally conductive clamps that are soldered to a board and that support portions of the perimeter of the cooling member.

Abstract: A module-type semiconductor device in which a plurality of IGBTs are incorporated in a package in such a way so as to provide a highly reliable pressure contact type semiconductor device having improved heat dissipation performance and small internal wiring inductance. A plurality of IGBTs are incorporated and arranged in a flat package with a hermetic structure consisting of common electrode plates exposed to top and bottom face sides, and an insulating outer frame interposed between the common electrodes plates and seal-joining those electrode plates. Contact terminal bodies which serve as both pressing members and heat radiators are interposed between the top-face-side common electrode plate and emitter electrodes of the respective opposing IGBTs. The emitter electrodes of the IGBTs and the common electrode, and the collector electrodes and the bottom-face-side common electrode, are directly brought in pressure contact with each other.

Abstract: To enable the mounting of arrester in a small-sized package of a resin-sealed type for general use, such as a T0-92 package or a T0-220 package, by modifying the arrangement of diodes and thyristor there is provided: a diode-bridge thyristor type of semiconductor arrester, comprising: a pair of opposed metal plates (20, 21); a thyristor (T1) between the metal plates (20, 21); three pairs of diodes (D1, D2: D3, D4: D5, D6) between the metal plates (20, 21); and three leads (22, 23, 24), each provided between each pair of diodes.

Abstract: An electronic package including a base member and associated cover member designed for being positioned together to compress at least two circuitized substrates (e.g., a ceramic substrate and a plurality of flexible substrates) positioned therein. One of the substrates is substantially rigid and is positively positioned in a protected, aligned manner within the base. Additionally, the flexible substrates are precisely aligned and initially secured to the rigid substrate, the invention further using yet another resilient means to act against each of the flexible substrates when the packages fully assemble. The cover is secured to the base to effect final compression of the internal elements. This package may be positioned on and electrically coupled to another circuitized substrate, e.g., PCB.

Abstract: An integrated circuit package of the surface-mountable type within which a battery is mounted is disclosed. Battery leads extend from the side of the package body opposite that which is adjacent the circuit board when mounted, and between which a conventional battery may be placed. Standoffs are located on the package body for supporting the battery above the package body, so that a gap is present therebetween. A housing is attached to the package over the battery, and has standoffs attached to its inner surface so that a gap is also present between the housing and the battery. The gaps may be air gaps or filled with a low thermal conductivity material. The gaps thermally insulate the battery from the package body and housing, so that the circuit may be subjected to solder reflow mounting to a circuit board, while insulating the high temperatures from the battery.

Abstract: Apparatus is presented herein for resiliently clamping at least one semi-conductor device to a support having an upper surface and wherein the semi-conductor device includes a housing having upper and lower spaced-apart relatively flat surfaces interconnected by an upstanding cylindrical wall. A leveller is provided having an upper dome-shaped contact surface and a lower surface having a circular-shaped first recess formed therein. The first recess is shaped and is of sufficient size to receive the upper portion of the housing including the upper surface thereof and a portion of the height of the cylindrical wall while the lower surface of the housing is located on the upper surface of the support. An elongated spring overlies and is resiliently biased toward and engages the dome-shaped contact surface of the leveller.

Abstract: An electronic package including a base member and associated cover member designed for being positioned together to compress at least two circuitized substrates (e.g., a ceramic substrate and a plurality of flexible substrates) positioned therein. One of the substrates is substantially rigid and is positively positioned in a protected, aligned manner within the base. Additionally, the flexible substrates are precisely aligned and initially secured to the rigid substrate, the invention further using yet another resilient means to act against each of the flexible substrates when the packages are fully assembled. The cover is secured to the base to effect final compression of the internal elements. This package may be positioned on and electrically coupled to another circuitized substrate, e.g., PCB.

Abstract: An enclosure for protectively housing a printed circuit board in an electronic circuit module includes a base having an internal surface and an external surface. The base includes a pair of raised mounting pads formed on the internal surface which define respective mounting surfaces. A pair of channels are also formed on the internal surface of the base. The enclosure further includes a cover having a panel portion and a pair of end wall portions. Respective projections are formed on each of the end wall portions which define grooves therein. The cover is assembled to the base by inserting the edges of the end wall portions provided on the cover into the channels provided on the base. A plurality of spring clips is disposed within each of the grooves provided on the cover. The spring clips can be positioned at any desired location along each of the grooves.

Abstract: A semiconductor device socket preventing adhesion of foreign material to mounting surfaces of external leads of a semiconductor device. In the semiconductor device socket, a positioning base supports a shoulder of each of external leads extending from the semiconductor device without contacting the base and the contact portion of each of the movable contact terminals makes electrical contact with the shoulder of the corresponding external lead. The movable contact terminals are disposed opposite to the external leads outside of the positioning base and are opened and closed as a movable cover is moved relative to the base.

Abstract: An IC package receptacle is disclosed in which, as an actuator is pushed down, a pushing surface thereof pushes down pressure bearing portions of a plurality of contacts against an elastic force to bring the contacts into and out of contact with leads of an IC package. To cope with an increase of the number of contact poles, the pushing load is reduced by providing a plurality of pushing load peaks brought about by different pushing surfaces. The contacts are grouped into a plurality of unit groups of contacts. The individual groups of contacts are pushed by the different pushing surfaces, respectively, thus providing a deviation between pushing load peaks and provided by the pushing surfaces on the respective unit groups of contacts.

Abstract: A heat sink and transistor retaining assembly for installation onto a printed circuit board. The assembly has a thermally conductive base plate forming a heat sink adapted to be disposed adjacent to the board, a first electric insulator attached to the base plate, a plurality of transistors positioned at predetermined positions against the first electric insulator so as to be electrically insulated from the base plate, a second electric insulator adjacent to the transistors with the transistors sandwiched between the insulators, and a resilient clamp attached to the base plate with the electric insulators and transistors positioned therebetween. The clamp has a plurality of retaining fingers that exert a retaining force on the transistors between the first and second insulators to retain the transistors in predetermined positions relative to the board.

Abstract: A family of modular hybrid assemblies with high frequency interconnections is effected by a high frequency circuit assembly attached to a motherboard. Each assembly comprises standardized conducting elements and customizable transitions and circuit regions. The customizable transitions can be placed anywhere along the conducting element and are capable of low and high frequency performance. Attachment of the assembly can be effected via a standardized clamping structure which compresses an elastomeric member upon the conducting elements or by bending the conducting elements and soldering on end to attachment sites on the motherboard. Each member of the family of modular hybrid assemblies provides a controlled impedance transition from a transmission line on the circuit assembly to a transmission line on the motherboard.

Abstract: A housing for accommodation of a plurality of electric circuitry packages, a method for assembling the housing, a cooling arrangement, and an electrical connection arrangement are disclosed. The housing can accommodate a plurality of packages, supply the packages with power, connect them electrically, support them and cool them. By means of the resilient support, the housing can withstand and protect the packages from shocks and vibrations. By means of the resilient connection, the housing can handle package size differences, e.g. due to thermal expansion caused by temperature changes. The cooling arrangement for cooling the electric circuitry packages includes several cooling units sandwiched with the packages into a stack. A cooling fluid cools the packages by flowing through each cooling unit. The units have flexible package facing walls, which form themselves to the package surfaces due to the cooling fluid pressure.

Abstract: A thermal attachment assembly for heat generating electronic devices which uses a canted coil spring to apply pressure directly against electronic components. The attachment assembly includes a heat sink housing in which the electronic components are pressed against an electrically insulating, thermally conductive film positioned against a surface of a shoulder or side wall of the heat sink housing. The force of the canted coil spring can be counterbalanced by a cover for the housing, or by an abutment that is either fixed in the housing or floats between attachment and an assembly at each of opposite sides of the housing.

Abstract: A substrate fixing apparatus in which a substrate such as a printed circuit board can be simply fixed in a main body of the product without separate fixture members. The apparatus comprises a chassis formed of a supporting jaw for supporting a substrate inwardly projected and first and second insertion holes vertically at an upper side of the supporting jaw, and at least one substrate holder fitted to the top end of the side surface of the chassis and the first and second insertion holes and having first and second resilient pieces for resiliently fixing the substrate, the resilient pieces being integrally formed with each other. Thus, the yield of the product can be improved by an automatized productive facilities with the cost of fabricating the product being reduced considerably.

Abstract: A pedestal 11 is attached to a circuit substrate 1 having a component placement area 4 when clamping portions 12 and 12 of the pedestal 11 clamp both side portions 5 and 5 of the component placement area 4. It is possible to stand the hybrid integrated circuit device on a parent circuit substrate a by itself before the hybrid integrated circuit device is soldered to the parent circuit substrate a. Since the bottom surfaces of the clamping portions 12 and 12 are flat. The circuit substrates 1, 1, . . . do not overlap one another when the hybrid integrated circuit devices are accommodated in and arranged vertically in a stick since the thickness of the clamping portions 12 and 12 of the pedestal 11 is thicker than the circuit substrate 1. Accordingly, the hybrid integrated circuit device is liable to vertically stand on the parent circuit substrate a by itself and it is easily accommodated in and taken out from the stick.

Abstract: A spring clip for urging an electrical component onto a heat sink housing within an electronics component module is described. The spring clip comprises an elongated planar body, retention device for securing the body of the spring clip to the heat sink housing, the retention device depending downward from the body. The spring clip also includes urging device for contacting and urging the electrical component into a heat conducting relationship with the heat sink housing. The urging device includes a first elongate member depending downward from the body to a u-shaped junction. A second elongate member, extending upward from the u-shaped member and terminating at a contact surface, maintains the electrical component in a heat conducting relationship with the heat sink housing.

Abstract: A self-encapsulated power conductor component with improved heat transfer has a chip bearing at least one power transistor having at least one interdigitated electrode, provided with an air bridge, and a sink provided with at least one metal islet in relief. The air bridge is reinforced and the chip is brazed in reverse to the islet of the sink by its air bridge. Other islets brazed to the metallizations on the rim of the chip reinforce the mechanical fixing. The access to the electrodes is obtained by via holes and the second face of the substrate may receive non-integrable components. The device can be applied to power transistors and integrated circuits, notably on GaAs.

Abstract: An electric circuit apparatus comprises an electrically connecting member including a holding body made of an electrically insulating material and a plurality of electrically conductive members embedded in the holding body. First end portions of the electrically conductive member extend through a first side of the holding body and second end portions of the electrically conductive member extend through the other side of the holding body. A plurality of electric circuit components are connected to the second end portions of the electrically conductive members.

Abstract: A container type semiconductor device containing many semiconductor elements is provided. The device allows heat to be dissipated from both sides of each semiconductor element by placing metal contact plates against the emitter electrodes of each semiconductor element. The metal contact plates are held firmly in place by spring means which also make contact with inner face of a terminal which is exposed outside the container. Heat flows from each semiconductor element through the spring means to the external terminal where the heat is dissipated. In one embodiment, the spring means are used also as a path for the flow of current to the terminal. Because wiring is not used, inductance is low making the device suitable for high frequency applications.

Abstract: A vertical lead-on-chip package and the method of making defines a high density array of semiconductor devices with leads extending from and across one face of the device, to the edge of the device such that a plurality of devices are vertically mounted on a circuit board. Each device has a heat sink thereon which is held in a fixture which serves as an array heat sink during testing and burn-in and during mounting and operation of the devices on the circuit board.

Abstract: A load spring for heat sink assemblies has elongated body with a plurality of fingers and a wedge member positioning the spring with respect to a wall of a heat sink housing. The fingers apply a force onto the electrical components to clamp the electrical components against the heat sink housing to provide heat dissipation from the electrical components to the housing.

Abstract: In a large-area controlled-turn-off high-power semiconductor component containing a multiplicity of finely structured individual components, a semiconductor device (12) is formed by a multiplicity of small-area semiconductor chips (7) which are accommodated alongside one another in a common housing (13) and connected in parallel. This achievement avoids problems of yield with structures which are becoming finer.