The patent's assignee for patent number 8642902 is
News editors obtained the following quote from the background information supplied by the inventors: "Surface-mountable devices conventionally comprise a carrier plate, an electrical component arranged thereon and a housing, which consists of a molding compound, for example. Hitherto, the contact-connection of the electrical component has usually been effected by means of a bonding wire led from a top side of the component to the carrier plate, and by a conductive adhesive at an underside of the component. In this case, the base area of the housing is usually smaller than the base area of the carrier plate. The carrier plate thus projects beyond the housing at two opposite sides in order, in regions of the projecting carrier plate, to lead electrical guides, for example conductor tracks, onto a mounting side of the carrier plate, which is arranged in a manner lying opposite the housing. However, a device embodied in this way with a carrier plate projecting beyond the housing disadvantageously leads to an increased space consumption."
As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "One object of the invention is to provide a surface-mountable device which is particularly space-saving, in particular has a small device size and a small lateral extent.
"This and other objects are attained in accordance with one aspect of the invention directed to a surface-mountable device, comprising a mounting side, a top side lying opposite the mounting side, an electrically insulating carrier plate, an electrical component and a housing. The carrier plate terminates the device toward the mounting side and has a fixing side lying opposite the mounting side, conductor tracks being arranged on said fixing side for the purpose of making electrical contact with the component. Contact areas are arranged on the mounting side of the carrier plate. Furthermore, the carrier plate has openings, wherein in each case a contact area is electrically conductively connected to a conductor track by means of an opening. The component is arranged on the fixing side of the carrier plate and is enclosed by the housing. At least one opening in the carrier plate is arranged below the component. The housing is arranged on the fixing side of the carrier plate and terminates the device toward the top side. The housing and the carrier plate are arranged flush with one another in a plan view of the carrier plate.
"Electrical guides, for example conductor tracks, from the fixing side of the carrier plate to the mounting side of the carrier plate are thus led via openings, so-called microvias. The latter are preferably arranged below the component. As a result, projecting carrier plate regions which serve for leading the conductor tracks onto the mounting side of the carrier plate are advantageously not necessary. The device size, in particular the lateral extent of the device and the base area of the device, can thus advantageously be reduced. This is advantageous in particular for devices which comprise comparatively large components, and/or for devices which have a certain complexity, in particular a plurality of external electrical connection locations.
"The device can preferably be arranged with the mounting side on a printed circuit board, wherein the contact areas of the device are preferably electrically conductively connected to connection locations of the printed circuit board, for example by means of a conductive adhesive. Consequently, the electrical contact-connection of the electrical component of the device leads from the connection locations of the printed circuit board via the contact areas and the openings of the carrier plate to the conductor tracks on the fixing side of the carrier plate.
"In one preferred configuration of the surface-mountable device, the openings of the carrier plate are arranged exclusively below the component.
"This advantageously further decreases the device size, in particular the lateral extent of the device. A space-saving surface-mountable device is advantageously possible.
"In a further preferred configuration of the surface-mountable device, the housing completely electrically insulates the component and the conductor tracks toward the outside.
"External electrical guides, for example electrical guides of adjacent electrical components, can thus advantageously be arranged on the housing or at side areas of the housing without in this case producing a short circuit of the device, in particular of the electrical component of the device. Space-saving arrangements comprising a plurality of electrical devices or components are thus advantageously possible.
"The housing is preferably composed of a material that is electrically insulating. Particularly preferably, the housing comprises a molding compound.
"In a further preferred configuration of the device, the device is electrically conductively contact-connectable toward the outside exclusively via the mounting side.
"In particular, the device is preferably electrically conductively contact-connectable exclusively by means of the openings.
"By virtue of the fact that the device is electrically conductively contact-connectable exclusively via the mounting side by means of the openings, and the top side of the device, in particular the housing of the device, is embodied as electrically insulating, the risk of a short circuit of the device, in particular of the electrical component, can advantageously be minimized.
"Particularly preferably, the device has side areas, wherein the side areas and the top side of the device are embodied as completely electrically insulating toward the outside.
"In particular, the device has no electrical guides, in particular conductor tracks and/or bonding wires, which reach as far as the side areas of the device and are electrically contact-connectable toward the outside there. The side areas and/or the top side of the device thus advantageously afford the possibility of being available for, for example, external electrical guides of, for example, adjacent electrical components. Arrangements of external electrical components near the device are thus advantageously made possible, as a result of which space-saving arrangements of multiple electrical components or devices can be realized.
"In one preferred configuration, an electrically insulating separating layer is arranged between the component and the carrier plate.
"In particular, conductor tracks arranged on the fixing side of the carrier plate are preferably covered wholly or partly with the electrically insulating separating layer. This results in an electrical insulation between the component and the conductor tracks in the region where the component is fixed.
"Preferably, the electrical component is electrically conductively connected to the conductor tracks, in particular by means of bonding wires, at a top side remote from the carrier plate. In particular, a respective bonding wire leads from the top side of the component to a respective conductor track of the carrier plate. In this case, the electrical contact-connection of the component is therefore effected only from the top side of the component. Other single-sided electrical contact-connections of an electrical component and electrical guides connected thereto in the electrical component, such as flip-chip components, for example, are known to the person skilled in the art and will therefore not be explained in any greater detail at this juncture.
"In a further configuration of the surface-mountable device, the component is arranged on an opening of the carrier plate and is electrically conductively connected to a contact area through the opening.
"A two-sided contact-connection of the electrical component is possible in this case. One electrical contact-connection is led at an underside of the component via the opening to the contact area. By contrast, the second electrical contact-connection of the component can be led from the top side of the component by means of a bonding wire to a respective conductor track.
"If an electrically insulating separating layer is arranged between the component and the carrier plate in this case, then there is arranged in the separating layer an opening which, in particular, contains an electrically conductive material and electrically conductively connects the underside of the component to the opening of the carrier plate, and thus the contact area.
"Preferably, the component is fixed by means of an adhesive, a conductive adhesive or an electrically conductive solder.
"In one preferred configuration of the device, the component has an active layer suitable for generating or for detecting electromagnetic radiation.
"The active layer of the component preferably has at least one pn junction, a double heterostructure, a single quantum well structure (SQW, single quantum well) or a multiquantum well structure (MQW, multiquantum well) for generating radiation. In this case, the designation quantum well structure does not exhibit any significance with regard to the dimensionality of the quantization. It therefore encompasses, inter alia, quantum wells, quantum wires and quantum dots and any combination of these structures.
"Particularly preferably, the component has a radiation exit side lying opposite the carrier plate, through which radiation exit side radiation generated in the component can leave the component. Preferably, the top side of the component is the radiation exit side.
"The component is preferably a semiconductor body, particularly preferably a thin-film semiconductor body. In the context of the application, a thin-film semiconductor body is considered to be a semiconductor body during whose production the growth substrate, onto which a semiconductor layer sequence comprising a semiconductor body of the thin-film semiconductor body was grown epitaxially, for example, has been stripped away.
"The layers of the semiconductor body are preferably based on a III/V compound semiconductor material. A III/V compound semiconductor material comprises at least one element from the third main group such as, for example, Al, Ga, In and one element from the fifth main group such as, for example, N, P, As. In particular, the term III/V compound semiconductor material encompasses the group of binary, ternary and quaternary compounds containing at least one element from the third main group and at least one element from the fifth main group, in particular nitride and phosphide compound semiconductors. Moreover, such a binary, ternary or quaternary compound can comprise, for example, one or more dopants and additional constituents.
"Particularly preferably, the component is an LED, an IRED, a phototransistor, a photodiode or an opto-IC.
"If the component is substantially provided for detecting radiation, and is embodied for example as a photodiode, phototransistor or opto-IC, then the layers of the component preferably contain silicon.
"Preferably, the housing is transparent to the radiation emitted or to be detected by the component. The radiation generated or to be detected by the component can thus be coupled out through the housing. In particular, the housing has a low absorption coefficient for the radiation emitted or to be detected by the component.
"Alternatively, the housing can be radiation-opaque to radiation in a wavelength range. In this case, the housing serves for wavelength selection. Radiation in a specific, in particular undesired, wavelength range can thus be filtered out selectively from the wavelength range of the radiation emitted or to be detected by the component. The housing thus serves as a filter for specific wavelengths.
"In one preferred configuration of the device, a plurality of electrical components are arranged on the fixing side of the carrier plate, said components in each case being enclosed by the housing.
"A plurality of devices can thus advantageously be produced during a production method. Mass production of surface-mountable devices is advantageously made possible.
"In particular, a plurality of devices are thus produced, which are subsequently separated from one another by means of singulation, for example by sawing in two directions. In this case, all four side areas of the device are produced by sawing. Alternatively, sawing can be effected only in one direction for singulation purposes, such that only two side areas of the device are produced by sawing.
"In particular, carrier plates having only one layer and carrier plates having a multilayered construction are conceivable for the device. In one preferred configuration of the device, the carrier plate has a multilayered construction. By virtue of a multilayered construction, properties of the carrier plate can be adapted to desired requirements. By way of example, a multilayered carrier plate is distinguished by an improved resistance to creapage current, improved radiofrequency properties or low water absorption.
"Preferably, the carrier plate contains a base material, for example a ceramic or epoxy resin, and a glass fiber fabric contained therein. In particular, the carrier plate is preferably electrically insulating.
"In one preferred configuration, the openings of the carrier plate each comprise an electrically conductive material. In this case, the openings can be partly or completely filled with the electrically conductive material. The electrically conductive material is a metal or a metal alloy, for example.
"Preferably, the openings of the carrier plate contain an electrically conductive solid body that is preferably inserted into the openings. Preferably, the solid body is in this case adapted to the size of the opening in such a way that it completely fills the latter after insertion. By way of example, the solid body can contain copper or consist of copper.
"As a further variant it is conceivable for the openings to be filled with an electrically insulating material and/or to be covered with an electrically insulating material. In particular, the openings can be covered by means of the electrically insulating separating layer arranged between component and carrier plate.
"The openings of the carrier plate can accordingly be designed in an application-specific fashion. In particular, the openings can contain, depending on the field of application, an electrically conductive filling compound, an electrically insulating filling compound and/or air."
For additional information on this patent, see: Schumann, Michael; Hoefer, Thomas; Kuhlmann, Werner. Surface Mountable Device. U.S. Patent Number 8642902, filed
Keywords for this news article include: Electronics, Circuit Board, Phototransistors,
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