Abstract:
An electronic device may include a substrate, and an integrated circuit over the substrate. The substrate may be provided with an electrical connection network including electrical links for linking the integrated circuit to another electrical device. Some of the electrical links may include an impedance-compensating inductor.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to the field of electronic devices including integrated circuits and related methods. 
       BACKGROUND 
       [0002]    Generally, an electrical connection network comprises electrical connection tracks (i.e. traces) linked to the integrated circuit chip, for example, by way of electrical connection beads (balls) or columns (vias). When the printed circuit board is placed on the other side of the substrate board bearing the integrated circuit chip, the traces are linked to the printed circuit board by way of electrical connection vias passing through the substrate board and of electrical connection beads or columns. 
         [0003]    When the printed circuit board is placed on the same side of the substrate board as the integrated circuit chip, the electrical connection traces are directly linked to the printed circuit board by way of electrical connection beads or columns. In the case where electrical connection traces are used for the transfer of high-frequency digital signals, which are required to have ever sharper edges, the above devices may degrade digital signals. 
       SUMMARY 
       [0004]    The present disclosure may improve electrical links between integrated circuit chips carried by substrates and other electric devices. 
         [0005]    An electronic device may comprise a substrate, and at least one integrated circuit assembled on the substrate. The substrate may be provided with an electrical connection network comprising a plurality of electrical links for linking the integrated circuit to another electric device, and in which at least one of the electrical links comprises at least one impedance-compensating inductor. 
         [0006]    The electrical link may comprise an electrical connection trace and an external electrical connection element, the inductor being placed between this trace and this element. The inductor may comprise a coil formed flat onto the substrate board and around an electrical connection region. The electrical connection region may be placed at one end of an electrical connection via passing through the substrate board. The inductor may be incorporated into a specific attached electrical connection component, for example, inserted in a through-passageway of the substrate board. The electrical link may comprise a transmission line for high-frequency digital signals. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Some electronic devices will now be described by way of non-limiting examples, illustrated by the drawing in which: 
           [0008]      FIG. 1  is a schematic diagram of a cross-sectional view of an assembly of an electronic device. 
           [0009]      FIG. 2  is a top plan view of a substrate of the electronic device in  FIG. 1 . 
           [0010]      FIG. 3  is a schematic diagram of a cross-sectional view of another embodiment of the electronic device. 
           [0011]      FIG. 4  is a schematic diagram of a cross-sectional view of another embodiment of the electronic device. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    An electronic device  1  shown in  FIGS. 1 and 2  comprises a substrate board (i.e. substrate)  2  made of an insulating material, which is provided, above a front face  3 , with an integrated circuit chip  4 . The substrate board  2  is provided with an electrical connection (i.e. electrical interconnect) network  5  comprising a plurality of electrical links  6  enabling the chip  4  to be linked to another electronic device  7 , which comprises, for example, a printed circuit board  8  placed above a back face  9  of the substrate board opposite its front face  3 . 
         [0013]    Each electrical link  6  comprises an electrical connection trace  10  arranged on the front face  3  of the substrate board  2  and an electrical connection element  11 , such as a bead, interposed between a front contact region  12  provided at one end  11  of the electrical connection trace  10  and a contact region  13  of the chip  4 . Each electrical link  6  further comprises an electrical connection via  14  arranged in a passageway  15  passing through the substrate board  2 , made of an electrically conductive material at least partly filling the passageway  15 , and an external electrical connection element  16 , such as a bead, interposed between a back contact region  17  provided on a back face of the electrical connection via  14  and a contact region  18  of the printed circuit board  8 . 
         [0014]    The plurality of electrical links  6  is divided into two groups of electrical links  6   a  and  6   b.  In the first group of electrical links  6   a,  the other end of the electrical connection trace  10   a  of each electrical link is directly linked to the corresponding electrical connection via  14   a.  In the second group of electrical links  6   b,  the other end of the electrical connection trace  10   b  of each electrical link is linked to the corresponding electrical connection via  14   b  by way of an impedance-compensating inductor  19 , which comprises a coil  20  arranged on the front face  3  of the substrate board  3 , which is formed at the same time as the electrical connection trace  10   b  and around an electrical connection region  19   a  placed on one end of the electrical connection via  14   b.    
         [0015]    The electrical links  6   b  can be specifically assigned to the transmission, in one direction and/or the other, of high-frequency signals, for example, video signals. The presence in these links  6   b  of the inductors  19 , arranged as close as possible to the electrical connection vias  14 , makes it possible to compensate for the drops in impedance due, in particular, to the existence of the electrical connection vias  14  and the electrical connection elements  16 , by raising them in such a way that the values of the impedances in the electrical links  6   b  are, for example, above a determined threshold. 
         [0016]    In another embodiment illustrated in  FIG. 3 , each electrical link of a group of electrical links  6   c,  equivalent to those of the group of electrical links  6   b  but without the presence of the inductor  19 , comprises a specific electrical connection component  21  inserted in the through-passageway  15  of the substrate board  2 , in place of the corresponding electrical connection via. 
         [0017]    The specific electrical connection component  21 , which can be of CMS or surface mount device (SMD) type, can comprise, in an embodiment, a cylindrical base  22  that bears, on its periphery, a wire coil  23  forming an impedance-compensating inductor  24  and comprises a front electrical connection pad  25  and a back electrical connection pad  26  which are linked to the ends of the inductor  24 . This specific attached component could have a different structure. 
         [0018]    Each electrical link  6   c  comprises an electrical connection trace  10   c,  which is linked directly to the front electrical connection pad  25  of the specific electrical connection component  21 . Whereas, the back electrical connection pad  26  is linked to a back contact region  17   c,  on which an electrical connection element  16   c  such as a bead is placed. 
         [0019]    In another embodiment illustrated in  FIG. 4 , each electrical link of a group of electrical links  6   d,  equivalent to those of the group of electrical links  6   b  but also without the presence of the inductor  19 , comprises an electrical connection via  14   d,  an electrical connection trace  10   d  linked directly to this via  14   d,  and a specific external electrical connection component  27 , equivalent to the specific component  21 , set out and attached in place of the corresponding external electrical connection back element. The specific electrical connection component  27  comprises an impedance-compensating inductor coil  28 , linked to opposing electrical connection pads  29  and  30 , the latter being linked to the electrical connection via  14   d  passing through the substrate board  2  and to the printed circuit board  8  respectively. 
         [0020]    In another embodiment, the printed circuit board  8  could be placed on the same side of the substrate board  2  as the integrated circuit chip  4 . In this case, the electrical connection vias  14  would be dispensed with and the electrical links would comprise electrical connection elements between the front face  3  of the substrate board  2  and the printed circuit board  8 , either by electrical connection elements, such as beads, placed on the electrical connection regions  19   a  when an inductor equivalent to the inductor  9  was provided, or by specific components forming inductors equivalent to the specific components  27 . The present embodiments are not limited to the examples described above. Other variants and other embodiments are possible without departing from the context of the present disclosure.