Abstract:
A sensor component and a panel used for the production thereof is disclosed. The sensor component has, in addition to a sensor chip with a sensor region, a rear side and passive components. These are embedded jointly in a plastics composition, in such a way that their respective electrodes can be wired from an overall top side of a plastic plate.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This Utility Patent Application claims the benefit of the filing date of Application No. DE 103 28 265.3, filed Jun. 23, 2003 and International Application No. PCT/DE2004/001147 filed Jun. 4, 2004, both of which are herein incorporated by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a sensor component and a panel with a plurality of sensor component positions, sensor chips with sensor regions and with contact areas on their active top sides being arranged in the positions. 
     BACKGROUND 
     The sensor chips of sensor components have hitherto been arranged on a circuit substrate or on a panel in the form of a printed circuit board with a plurality of sensor component positions. An arrangement of this type necessitates producing, toward the circuit substrate or toward the panel, in each of the sensor component positions, connections from the contact areas to contact pads on the circuit substrate. These connections are created by means of time-consuming and cost-intensive, and also thermally stressing connection techniques, which restricts the reliability of the sensor component and at the same time causes high costs. 
     SUMMARY 
     The present invention provides a sensor component which has an improved reliability and can be produced more cost-effectively. 
     In one embodiment, the invention provides a sensor component having a sensor chip with a sensor region on its active top side. The electrodes of the sensor region are connected via conductor tracks to contact areas on the active top side of the sensor chip. The sensor chip is embedded in a plastic plate by its rear side and by its edge sides, the active top side of the sensor chip together with a top side of the plastic plate forming an overall top side. A rewiring structure with a rewiring layer is arranged on the overall top side, the rewiring lines extending from the contact areas to external contact areas of the sensor component. 
     A sensor component of this type has the advantage that it is not necessary to overcome level jumps for the electrical connections between sensor chip and plastic plate, rather the rewiring structure with its rewiring lines is arranged on an overall top side. Complex connection techniques, such as bonding technique or flip-chip technique, are consequently obviated. Moreover, with the sensor chip as many semiconductor chips and passive components as desired can be embedded in the plastic plate to form a sensor module. For this purpose, electrode areas of passive components embedded in the plastic plate, are provided in the overall top side. In this case, the rewiring lines on the overall top side connect electrode areas of the passive components to contact areas of the sensor chip and/or of the semiconductor chip and/or of the external contact areas. 
     Such wiring with the aid of rewiring lines is effected within a single rewiring layer. This rewiring layer may be extended by further insulation layers and rewiring layers, a plurality of rewiring layers being connected to one another via through contacts through the insulation layers. This results in a multilayer rewiring structure that is formed without a high outlay on to the overall top side comprising semiconductor top sides and plastic top sides. 
     Instead of an arrangement of sensor chip and semiconductor chip alongside one another, it is also possible to accommodate a stacking of a sensor chip with a semiconductor chip one above the other in the plastic plate. This has the advantage that the overall top side of the sensor component can be kept small. 
     The sensor region may react to pressure, temperature, thermal radiation or electromagnetic radiation. 
     In a further embodiment of the invention, a lens is arranged above the sensor region in order to achieve a higher optical sensitivity. The lens may be composed of glass or have a flat lens film with Fresnel rings, which has the advantage that the height of the sensor component is not significantly increased by fitting a Fresnel lens. 
     Outside the region of the sensor chip, in a further embodiment of the invention, the plastics composition may have through contacts to external contact areas which are situated opposite to the overall top side. This has the advantage that the sensor region is freely accessible, even if the sensor component is fixed on a printed circuit board with the aid of the external contacts. Otherwise, that is to say if no through contacts are provided through the plastics composition, and the external contacts are arranged on the same top side, that is to say on the common overall top side, it would be necessary to provide an opening in a printed circuit board arranged thereabove, thereby enabling access to the sensor region of the sensor chip. The through contacts to the external contact areas can be electrically connected via rewiring lines to the contact areas of the sensor chip on the overall top side. 
     A further aspect of the invention relates to an optoelectronic device, which has a sensor component accommodated in a camera housing. In this case, the sensor region of the semiconductor chip has a CCD structure or some other image recording structure by means of which, by way of example, images can be recorded by means of a mobile phone and can be transmitted to a call partner. 
     The sensor component may also have an addition, such that it can be used as an optoelectronic coupling component. In this case, an optical fiber plug-in region, in which an optical fiber as optical waveguide can be plugged in, is arranged above the sensor region. Optoelectronic coupling components of this type are required in large quantities, so that the cost-effective production of the sensor component according to the invention is advantageous. 
     A further aspect of the invention relates to a panel having component positions arranged in rows and columns for sensor components. In this case, the panel already has all the circuit components of the sensor component, such as sensor chip with sensor region and with contact areas, top sides of semiconductor chips with contact areas, electrodes of passive strip elements, a plastic top side surrounding the semiconductor chip top sides, a rewiring structure on an overall top side. In this case, the rewiring structure has a rewiring layer with rewiring lines which connects the contact areas of the sensor chips to external contact areas of the sensor component. On the overall top side of the panel, external contacts may also be arranged on the external contact areas in order to complete a sensor component in each of the component positions before the panel is separated into individual components. 
     In one embodiment, a method for the production of a panel includes the following: 
     Provision is made of a semiconductor wafer having sensor chip positions arranged in rows and columns. Afterward, the semiconductor wafer is separated into individual sensor chips with a sensor region and contact areas on an active top side of the sensor chips. An adhesive film or an adhesive plate is then inserted into a first mold half with component positions arranged in rows and columns. There is then applied to the component positions of the adhesive film or of the adhesive plate in each case a sensor chip of the semiconductor wafer in the component positions with adhesive bonding of the active top side of the sensor chips on to the adhesive side of the adhesive film or the adhesive plate. 
     The mold halves are then brought together and a plastics composition is injected into the mold with the sensor chips being embedded on one side. After the plastics composition has been cured to form a composite plate comprising plastics composition and sensor chips, the mold halves are moved apart and the composite plate is removed. Finally, the adhesive film or the adhesive plate is removed from the composite plate and a rewiring structure is applied to the freed overall top side of the composite plate. 
     This method has the advantage that after the injection-molding of the composite plate, a common overall top side for the application of further coatings is available simultaneously for a plurality of sensor components. Furthermore, the method has the advantage that neither a step between the active top side of the sensor chip and the plastics composition nor a distance between the active top side of the sensor chip and the plastics composition occurs, so that the entire sensor component can be wired with a single rewiring layer. This rewiring layer of the rewiring structure has rewiring lines that connect the contact areas of the sensor chip to external contact areas of the sensor component. Furthermore, external contacts in the form of solder bumps or solder balls or external contact pads can be applied to said external contact areas whilst still in the state of the panel. 
     In a further exemplary implementation of the method, electrodes of passive components are concomitantly applied to the adhesive film or adhesive plate, so that it is possible to realize a more complex sensor circuit for the sensor component. Furthermore it is also possible to position additional semiconductor chips with integrated circuits in the component positions, to be precise in each case with their contact areas on the adhesive film or adhesive plate, in order that when the adhesive film or adhesive plate is stripped away, the contact areas of the additionally integrated circuits can be contact-connected by rewiring lines. 
     Consequently, this method makes it possible to construct complex sensor components in an extremely simple manner, only one molding step being required for creating the card-type housing and only one patterned rewiring layer being required for the connection of the individual circuit components in the form of passive components and integrated circuit elements and sensor chips. If the sensor chip and a semiconductor chip with integrated circuit should be stacked one above the other, then it is necessary to carry out an internal stack wiring prior to embedding in the common plastic plate and/or an elevation of the contact areas of the lower semiconductor chip is required in order to wire them on the overall top side with other components of the sensor component. 
     A method for the production of a sensor component has the additional method that after the production of a panel, external contacts are also applied to the external contact areas and the panel is subsequently separated into individual sensor components. 
     To summarize, it can be stated that the invention produces an inexpensive, space-saving housing which additionally has a good characteristic with regard to moisture sensitivity. This is achieved by virtue of the fact that the housing is constructed on the basis of a so-called “universal package” technology. Unlike in the mounting of normal, non-optical semiconductors, in the case of the optoelectronic components, the sensor areas are not covered by dielectrics or soldering resists, but rather are left free for later covering with optical materials or optical components, for example lenses. To summarize, the following advantages are thus afforded:
     1. low production costs of the housing;   2. small space requirement of the housing as is required for mobile phone cameras, for example;   3. a surface mounting of the housing is possible on account of the low moisture sensitivity, which means that the component according to the invention can be soldered on to a circuit board of a higher-level circuit in normal surface-mounting processes without any problems.   

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. 
         FIG. 1  illustrates a schematic perspective view of a sensor component of a first embodiment of the invention. 
         FIG. 2  illustrates a schematic cross section through a sensor component in a housing in accordance with a second embodiment of the invention. 
         FIG. 3  illustrates a schematic cross section through a sensor component as coupling component in accordance with a third embodiment of the invention. 
         FIG. 4  illustrates a schematic cross section through a sensor component position of a panel prior to the application of external contacts. 
         FIG. 5  illustrates a schematic cross section through a sensor component after application of a lens to a sensor region of the component as fourth embodiment of the invention. 
         FIG. 6  illustrates a schematic cross section through a sensor component in accordance with a fifth embodiment of the invention. 
         FIG. 7  illustrates a schematic cross section through a sensor component in accordance with a sixth embodiment of the invention, 
         FIG. 8  illustrates a schematic cross section through a sensor component in accordance with a seventh embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a schematic perspective view of a sensor component  1  of a first embodiment of the invention. A sensor chip  2  is embedded by its edge sides  36 ,  37 ,  38  and  39  in a plastic plate  6  with the edge sides  8 ,  9 ,  11  and  12 . An active top side  5  of the sensor chip  2  and a top side  35  of the plastic plate  6  form an overall top side  13 . In addition to the active top side  5  of the sensor chip  2 , the overall top side  13  comprises an active top side of an additional semiconductor chip  21 , on which contact areas  29  are arranged. Furthermore, the electrode areas  18  of three passive components  19  are arranged on the overall top side  13 . 
     Besides the contact areas  4  and  29  or of the both of the sensor chip  2  and of the semiconductor chip  21  and of the electrodes  18  of the passive components  19 , the overall top side has external contact areas  17  on which external contacts  25  are arranged. 
     A rewiring layer  15  is arranged on the overall top side  13 , which rewiring layer, with its rewiring lines  16 , connects contact areas  4  of the semiconductor chip  2  to contact areas  29  of the semiconductor chip  21  and connects contact areas  4  to electrode areas  18 , and, via further rewiring lines  16 , connects the contact areas  4  and  29  and also the electrode areas  18  to external contact areas  17  on the overall top side  13 . Consequently, the sensor component  1  shown in  FIG. 1  already constitutes a sensor module and can be connected via the external contacts  25  to a higher-level circuit on a printed circuit board. In the case of such surface mounting of a sensor component of the first embodiment of the invention, as shown in  FIG. 1 , it is necessary to provide an opening in the higher-level circuit board, said opening corresponding to the sensor region  3  of the sensor chip  2 , in order to enable access on the sensor region  3 . 
       FIG. 2  illustrates a schematic cross section through a sensor component  10  in a camera housing  26  in accordance with a second embodiment of the invention. Components having functions identical to those in  FIG. 1  are identified by the same reference symbols and are not discussed separately. 
     The sensor component  10  is a part of a camera component  41 , and is arranged on a higher-level circuit board  42  in the camera housing  26  of a mobile telephone. The three components, system component  10 , circuit board  42  and camera housing  26 , are arranged one above another, the sensor component  10  being arranged below the higher-level circuit board  42  and the circuit board  42  being arranged below the camera housing  26 . The sensor component  10  has a sensor chip  2 , a semiconductor chip  21  and passive components  19 . The sensor chip  2  has an active top side  5  with a sensor region  3  and contact areas  4  and a rear side  7 . The semiconductor chip  21  has contact areas  29 , and the passive component  19  has electrode areas  18 . 
     The sensor chip  2 , the semiconductor chip  21  and the passive components  19  are embedded in a plastic composition  31  in such a way that they form a plastic plate  6  having an overall top side  13  with the sensor region  3 , the contact areas  4  and  29  and the electrode areas  18 . Rewiring lines  16  which interconnect the circuit elements  2 ,  19  and  21  and produce electrical connections to external contact areas  17  are arranged on said overall top side  13 . External contacts  25  which are soldered to the higher-level circuit board  42  are arranged on the external contact areas  17 . 
     The rewiring lines  16  form a rewiring layer  15 , which is part of a rewiring structure  14 , the rewiring structure  14  additionally having an insulating covering layer  45 , which leaves only the sensor region  3  and the external contact areas  17 . The sensor region  3  bears a lens  22  oriented with respect to the optical axis  47  of a second lens  34 , the second lens  34  being oriented between camera housing  26  and higher-level circuit board  42 . 
     The higher-level circuit board  42  and the camera housing  26  have openings  43  and  44 , the side of which corresponds to the sensor region  3  of the sensor chip  2 , so that the optical impression of the surroundings can act on the sensor region  3  of the sensor chip  2  via the lenses  34  and  22 . A sealing element  46  between the second lens  34  and the camera housing  26  ensures that no moisture and no dust particles can penetrate into the housing  26 . 
       FIG. 3  illustrates a schematic cross section through a sensor component  20 , designed as a coupling component in accordance with a third embodiment of the invention. Components having functions identical to those in the previous figures are identified by the same reference symbols and are not discussed separately. 
     The sensor component  20  has a similar construction to the sensor component  10  in  FIG. 2 , but the lens  22  is oriented to an optical fiber  51 . Instead of the camera housing  26  as in  FIG. 2 , an optical fiber plug-in region  27  with an optical fiber plug-in base  48  is arranged above the opening  44  in the higher-level circuit board  42  and fixed on the higher-level circuit board  42 . The optical fiber plug-in base  48  is structured in such a way that a plug-in sleeve  49  which is fixed on the optical fiber  51  can be brought into engagement with the optical fiber plug-in base  48 . The optical fiber plug-in base  48  is oriented in such a way that the optical axes  47  of the optical fiber  51  and the lens  22  are oriented with respect to one another. 
       FIG. 4  illustrates a schematic cross section through a sensor component position  33  of a panel  28  prior to the application of external contacts and prior to the separation of the panel  28  into individual sensor components. Components having functions identical to those in the previous figures are identified by the same reference symbols and are not discussed separately. 
     The panel  28  has a composite plate  32  with a plastic plate rear side  24 . The composite plate  32  comprises a plastics composition  31  and sensor chips  2 , semiconductor chips  21  and passive components  19  embedded therein. The circuit components  2 ,  19  and  21  are embedded in the plastics composition  31  of the composite plate  32  in such a way that they form an overall top side  13  which is covered with a rewiring structure  14  comprising a rewiring layer  15  with rewiring lines  16 . An insulating covering  45  then leaves free only the sensor regions  3  and the external contact areas  17  in each of the component positions  33  of the panel  28 . 
       FIG. 5  illustrates a schematic cross section through a sensor component  30  after application of a lens  22  to a sensor region  3  of the sensor component  30  according to a fourth embodiment of the invention. The lens  22  and the external contacts  25  for each of the sensor components  30  may either already be applied to the panel shown in  FIG. 4  in each of the component positions or be subsequently fixed on each individual sensor component  30 . The fourth embodiment of the invention as shown in  FIG. 5  exclusively has external contacts  25  on external contact areas  17  which are connected via rewiring lines  16  to corresponding electrodes of the embedded circuit components of the sensor component  30 . 
       FIG. 6  illustrates a schematic cross section through a sensor component  40  of a fifth embodiment of the invention. Components having functions identical to those in the previous figures are identified by the same reference symbols and are not discussed separately. 
     The fifth embodiment of the invention in accordance with  FIG. 6  differs from the fourth embodiment in accordance with  FIG. 5  by virtue of the fact that in addition to external contacts  25  which are connected via rewiring lines  16  to the electrode areas  19  and contact areas  4  and  29  of the circuit components  2 ,  18  and  21  of the sensor component, distance-maintaining external contacts  52  are arranged on the overall top side. The external contacts  52  ensure, in the course of soldering the sensor component  40  on to a higher-level circuit board, that a sufficient distance between the lens  22  and the circuit board arranged thereabove is complied with. In the fifth embodiment of the invention, too, the circuit components such as sensor chip  2 , semiconductor chip  21  and passive components  19  are arranged in such a way that each of the components can be contact-connected by its electrodes from the overall top side  13 . 
       FIG. 7  illustrates a schematic cross section through a sensor component  50  of a sixth embodiment of the invention. This sixth embodiment of the invention differs from the previous embodiments by virtue of the fact that the semiconductor chip  21  and the sensor chip  2  are stacked one on top of the other prior to embedding in the plastics composition  31 . In the course of stacking, care is taken to ensure that the contact areas  29  are not covered by the sensor chip  2 , rather that the contact areas  29  can be occupied by thermocompression heads  53 , the height of which corresponds to the thickness of the sensor chip  2 . Consequently, the semiconductor chip  21  arranged below the sensor chip  2  can also be connected to the remaining components of the sensor component  50  via the overall top side  13  and the rewiring layer  15  arranged there. 
       FIG. 8  illustrates a schematic cross section through a sensor component  60  in accordance with a seventh embodiment of the invention. The seventh embodiment of the invention in accordance with  FIG. 8  differs from the previous embodiments by virtue of the fact that through contacts  23  are provided through the plastics composition  31 , the length of said through contacts corresponding to the thickness of the plastic plate  6 . It is thus possible to fit external contacts  25  on the rear side  54  of the sensor component  60 , which external contacts are then arranged in a manner situated opposite to the lens  22  or to the sensor region  3  of the sensor chip  2 . With this seventh embodiment of the invention it is possible to realize surface mounting on a higher-level circuit board, an opening in the higher-level printed circuit board not being required since the sensor region  3  of the sensor component  60  is freely accessible despite surface mounting on a higher-level circuit board.