Electronics unit with integrated metallic pattern

Abstract

A non-conductive encapsulation cover is mounted on a support face of a support substrate to delimit, with the support substrate, an internal housing. An integrated circuit chip is mounted to the support substrate within the internal housing. A metal pattern is mounted to an internal wall of the non-conductive encapsulation cover in a position facing the support face. At least two U-shaped metal wires are provided within the internal housing, located to a side of the integrated circuit chip, and fixed at one end to the metallic pattern and at another end to the support face.

Claims

1. A method, comprising: mounting at least one electronic integrated circuit chip on a bearing surface of a support substrate; locally forming a portion of solder material on the bearing surface; forming a metallic pattern at least on an internal wall of a non-conductive encapsulation cover; fixing first ends of a plurality of U-shaped metal wires onto the metallic pattern; mounting the non-conductive encapsulation cover on said bearing surface of the support substrate such that the internal wall is positioned opposite the bearing surface and second ends of the U-shaped metal wires are in contact with the locally formed portion of solder material; and raising a temperature of said locally formed portion of solder material so as to solder said second ends of the U-shaped metal wires onto the bearing surface.

2. The method according to claim 1, wherein a bend of each U-shaped metal wire provides said second end that is soldered to the bearing surface and wherein ends of two legs of each U-shaped metal wire extending from the bend provide said first end that is fixed to the metallic pattern.

3. The method according to claim 2, wherein the metallic pattern is an antenna.

4. The method according to claim 3, wherein the metallic pattern is a portion of an electromagnetic shield.

5. The method according to claim 1, wherein mounting the non-conductive encapsulation cover comprises attaching the non-conductive encapsulation cover to the bearing surface using an adhesive material, and wherein raising the temperature of said locally formed portion of solder material comprises applying heating to both cure the adhesive material and perform soldering of said second ends of the U-shaped metal wires onto the bearing surface.

6. The method according to claim 1, wherein forming the metallic pattern comprises performing a vapor phase metal deposition.

7. The method according to claim 1, wherein forming the metallic pattern comprises performing a direct laser engraving.

8. The method according to claim 7, wherein said direct laser engraving comprises laser direct structuring (LDS).

9. The method according to claim 1, wherein said locally formed portion of solder comprises a soft soldering paste.

10. The method according to claim 1, wherein mounting the non-conductive encapsulation cover comprises: depositing an adhesive material on said bearing surface of the support substrate; and placing ends of walls of the non-conductive encapsulation cover in contact with the adhesive material.

11. The method according to claim 10, wherein mounting the non-conductive encapsulation cover comprises applying heat to cure said adhesive material.

12. The method according to claim 11, wherein applying heat to cure said adhesive material further heats the locally formed portion of solder to perform the soldering of said second ends of the U-shaped metal wires onto the bearing surface.

13. The method according to claim 10, wherein said adhesive material is an epoxy.

14. The method according to claim 1, further comprising placing connecting wires extending between metallic pads of said at least one electronic integrated circuit chip and metallic areas located on the bearing surface.

15. The method according to claim 14, wherein the U-shaped metal wires are structurally identical to the connecting wires.

16. The method according to claim 14, wherein the U-shaped metal wires and the connecting wires are formed by bonding wires.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other advantages and features of the invention are described in the detailed description of embodiments and applications, which are by no means limiting, and the attached drawings in which:

(2) FIG. 1 is schematic diagram of a unit or device;

(3) FIG. 2 is schematic diagram of a unit or device;

(4) FIG. 3 is a plan view;

(5) FIG. 4 shows steps of a method; and

(6) FIG. 5 shows steps of a method.

DETAILED DESCRIPTION

(7) In FIG. 1, reference numeral 1 denotes a unit or device comprising a support substrate 10 having a bearing surface 100 and a non-conductive encapsulation cover 40 mounted on the bearing surface 100 by means of a strip of adhesive 50, having a thickness commonly referred to by a person skilled in the art as the bond line thickness (BLT).

(8) The adhesive is a known epoxy adhesive, for example.

(9) Typically, the thickness of this strip of adhesive 50 is limited in quantity to maintain a given position of vertical positioning of the cover on the substrate. For example, to maintain a precision of the vertical positioning of more or less 10 micrometers, the thickness of the strip of adhesive is capped at 15 micrometers.

(10) The support substrate 10 is designed to support at least one electronic integrated circuit chip 20 and to establish electrical connections between the terminals of the electronic integrated circuit chip and the exterior of the unit 1.

(11) The internal wall of the non-conductive encapsulation cover 40 delimits with the carrier substrate 10 an internal housing (or volume) 400 designed to receive the electronic integrated circuit chip 20.

(12) In the example illustrated in FIG. 1, the electronic integrated circuit chip 20 is electrically connected to metallic areas of the bearing surface 100 of the support substrate by connecting wires 21.

(13) The non-conductive encapsulation cover 40 also includes, on its internal wall located opposite the bearing surface 100 of the support substrate (i.e., on an underside of the front wall of the cover 40), a metallic pattern 60 which can be, for example, either: a solid metal plate in the case of an electromagnetic protective shield, or a specific metal pattern in the case of the formation of an antenna.

(14) In this embodiment, U-shaped metal wires 30 are also provided within the internal housing 400, located to the side of the electronic integrated circuit chip 20, and extending between the bearing surface 100 of the support substrate and the metallic pattern 60.

(15) In this embodiment, the bend of each U-shaped metal wire is located at the level of the metallic pattern and is fixed to the metallic pattern by means of an electroconductive soldering paste 302.

(16) Two legs 300 and 301 of each U-shaped metal wire extend from the bend and are fixed, for example by soldering, onto the metallic areas of the bearing surface 100 of the support substrate.

(17) In the embodiment variant illustrated in FIG. 2, this time the bends of the U-shaped metal wires are fixed onto the bearing surface of the support substrate by means of soldering pads 302. Furthermore, the legs 300 and 301 of the U-shaped metal wires are soldered onto the metallic pattern 60.

(18) It is possible advantageously, as illustrated very schematically in the plan layout of FIG. 3, to provide a plurality of U-shaped metal wires 30 arranged at the periphery of the internal housing 400 of the unit and therefore surrounding the electronic integrated circuit chip or chips located in the unit as well as all the other possible components.

(19) This is particularly advantageous in the case of an electromagnetic shield and makes it possible to obtain a dense peripheral network or curtain of U-shaped metal wires.

(20) Reference is now made in particular to FIGS. 4 and 5 to illustrate ways of implementing the method of manufacturing the unit.

(21) FIG. 4 refers more particularly to an implementation which makes it possible to obtain a unit of the type illustrated in FIG. 1, whereas FIG. 5 refers more particularly to a method of implementation which makes it possible to obtain a unit of the type illustrated in FIG. 2.

(22) In step S40 of FIG. 4, the support substrate is provided, on which in step S41 the mounting of the electronic integrated circuit chip is performed, including fixing the electronic integrated circuit chip as well as forming its electrical connection, for example by means of connecting wires 21.

(23) Then, in step S42, the formation and fixing of U-shaped metal wires 30 is performed on the metallic areas of the substrate.

(24) The method of forming said wires in a U shape is identical to that of forming the connecting wires 21 of the electronic integrated circuit chip. In particular, use of bonding wire technology and fabrication techniques may be used for both the connecting wires 21 and U-shaped metal wires 30.

(25) More precisely, conventionally, a wire is arranged having a ball at its end which is crushed onto a first metallic area of the substrate.

(26) Then the wire is shaped in order to obtain the U-shape and the end of the other branch of the U-shaped metal wire is crushed onto another metallic area of the substrate which fixes it and severs the rest of the wire, then forms again a ball which will be used for forming another U-shaped metal wire.

(27) Typically, the diameter of said U-shaped metal wires can vary between 20 and 25 micrometers.

(28) Therefore, at the end of step S42, U-shaped metal wires are obtained which are fixed onto the bearing surface of the substrate and project from said bearing surface. The height of the wires in the U-shaped metal wire can vary between 500 and 1000 Angstroms.

(29) In this way a very good degree of rigidity is obtained for the U-shaped metal wires and their flexibility makes it possible for them to easily withstand dilatation during the increase in temperature of the units.

(30) Steps S43 to S45 are performed parallel to steps S40 and S42.

(31) It should be noted here that, of course, said steps S43, S44 and S45 can be carried out before steps S40 to S42 or even after or even simultaneously to steps S40 to S42.

(32) In step S43, the non-conductive encapsulation cover 40 is provided and the metallic pattern is formed on its internal wall, which is designed to be opposite the bearing surface after mounting the cover on the support substrate.

(33) This metallic pattern can be formed or example by vapor phase metal deposition or by direct laser engraving known by the person skilled in the art as laser direct structuring (LDS).

(34) Then, in step S45, a localized deposit of a soft soldering paste is performed onto the metallic pattern, for example a soft paste with a base of tin, silver and copper.

(35) In step S46, the non-conductive encapsulation cover is mounted onto the support substrate. During this assembly the ends of the walls of the cover sink into the epoxy adhesive 50.

(36) Likewise, during this assembly, the bends of the U-shaped metal wire sink into the soft pads of soldering paste 302.

(37) Then the unit is heated S47.

(38) During the heating, the adhesive 50 polymerizes, for example at 150 C., so as to ensure the adhesion of the cover.

(39) Furthermore, the heating also enables the soft soldering paste to be heated to a high enough temperature, for example 260 C., to solder the U-shaped bend to the metallic pattern.

(40) Referring now to FIG. 5, it is shown that this time the localized deposit of soldering paste is performed in step S52 on the bearing surface of the support after step S50 of providing the support substrate and step S51 of mounting the electronic integrated circuit chip.

(41) With regard to the cover, the latter is provided in step S53 and the metallic pattern is formed in step S54.

(42) Then, the U-shaped metal wires are fixed, for example by soldering, onto the metallic pattern in step S55.

(43) This time there are U-shaped metal wires projecting from the internal wall of the unit.

(44) And, when mounting the non-conductive encapsulation cover onto the support substrate in step S56, the projecting ends of the U-shaped metal wires enter into the pads of soldering paste, which enable said projecting ends to be fixed onto the metal areas of the support substrate during the heating S57 of the unit.