Electronic device with at least one impedance-compensating inductor and related methods

The present disclosure relates to the field of electronic devices including integrated circuits and related methods.

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.

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.

The present disclosure may improve electrical links between integrated circuit chips carried by substrates and other electric devices.

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.

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.

Some electronic devices will now be described by way of non-limiting examples, illustrated by the drawing in which:

FIG. 1 is a schematic diagram of a cross-sectional view of an assembly of an electronic device.

FIG. 2 is a top plan view of a substrate of the electronic device in FIG. 1 .

FIG. 3 is a schematic diagram of a cross-sectional view of another embodiment of the electronic device.

FIG. 4 is a schematic diagram of a cross-sectional view of another embodiment of the electronic device.

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 .

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 .

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.

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.

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.

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.

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.

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.

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.