Electronic device comprising a substrate board equipped with a local reinforcing or balancing layer

1. An electronic device, comprising:

a substrate board having a front face;

at least one integrated-circuit chip mounted to the front face of said substrate board;

wherein the substrate board further includes an electrical connection network mounted on said front face and configured to make electrical connections to said integrated-circuit chip and further having a metal region;

at least one local reinforcing or balancing layer made of a non-metallic material mounted to a face of the substrate board in at least one local zone of the substrate board which is free of metal portions of said electrical connection network; and

wherein said electrical connection network includes vias extending through the substrate board, and

wherein said at least one local zone and said at least one local reinforcing or balancing layer are located between said vias and a peripheral edge of the substrate board, and said at least one local reinforcing or balancing layer does not extend over the vias.

2. The device according to claim 1 , wherein the at least one local zone of the substrate board is located on the front face adjacent to a portion of the electrical connection network, and said local reinforcing or balancing layer is mounted to the front face in the local zone.

3. The device according to claim 1 , wherein said local reinforcing or balancing layer comprises a plurality of points of non-metallic material bonded to the substrate board.

4. The device according to claim 1 , wherein said local reinforcing or balancing layer comprises at least one line or bead of non-metallic material bonded to the substrate board.

5. The device according to claim 1 , wherein said local reinforcing or balancing layer comprises at least one non-metallic film bonded to the substrate board.

6. The device according to claim 1 , further including a superficial passivating layer mounted to the front face of the substrate board over the electrical connection network.

7. The device according to claim 6 , wherein the superficial passivating layer is not present in the at least one local zone where said local reinforcing or balancing layer is mounted.

8. The device according to claim 6 , wherein the superficial passivating layer contains at least one hole, and wherein said local reinforcing or balancing layer is disposed in the at least one hole.

9. A process for fabricating an electronic device, comprising:

adding a local reinforcing or balancing layer made of a non-metallic material to a zone free from metal portions of a substrate board equipped with an electrical connection network and a metal region,

then mounting an integrated-circuit chip onto the substrate board by way of electrical connection elements placed in metal zones of said electrical connection network;

opening a hole in the superficial passivating layer; and

depositing a superficial passivating layer on the substrate board over the metal portions, wherein at least a portion of the local reinforcing or balancing layer is added in said hole.

10. The process of claim 9 , wherein said local reinforcing or balancing layer comprises a plurality of points of non-metallic material bonded to the substrate board.

11. The process of claim 9 , wherein said local reinforcing or balancing layer comprises at least one line or bead of non-metallic material bonded to the substrate board.

12. The process of claim 9 , wherein said local reinforcing or balancing layer comprises at least one non-metallic film bonded to the substrate board.

13. An electronic device, comprising:

a substrate board having, on a front face thereof, an electrical connection network, a metal region separate from said electrical connection network, and a local reinforcing layer made of a non-metallic material positioned in a local zone of the substrate board which is free of the metal region and said electrical connection network;

at least one integrated-circuit chip mounted to the front face of said substrate board and electrically connected to said electrical connection network; and

a superficial passivating layer mounted to the front face of the substrate board over the electrical connection network,

wherein the superficial passivating layer contains at least one hole, and

wherein a portion of said local reinforcing layer is disposed in said hole.

14. The device according to claim 13 , wherein said local reinforcing layer comprises one of: a plurality of points of non-metallic material bonded to the substrate board; a line or bead of non-metallic material bonded to the substrate board; or a non-metallic film bonded to the substrate board.

15. An electronic device, comprising:

a substrate board having, on a front face thereof, an electrical connection network, a metal region separate from said electrical connection network, and a local reinforcing layer made of a non-metallic material positioned in a local zone of the substrate board which is free of the metal region and said electrical connection network;

at least one integrated-circuit chip mounted to the front face of said substrate board and electrically connected to said electrical connection network;

a plurality of vias extending through the substrate board; and

wherein said local reinforcing layer extends over but is not electrically connected to said plurality of vias.

16. The device according to claim 15 , further including a superficial passivating layer mounted to the front face of the substrate board over the electrical connection network and the plurality of vias.

17. The device according to claim 15 , wherein said local reinforcing layer comprises a plurality of points of non-metallic material.

18. The device according to claim 15 , wherein said local reinforcing layer comprises at least one line or bead of non-metallic material.

19. The device according to claim 18 wherein said local reinforcing layer comprises a thermosetting epoxy adhesive.

20. The device according to claim 15 , wherein said local reinforcing layer comprises at least one non-metallic film.

21. The device according to claim 20 wherein a material of said local reinforcing layer is selected from a group consisting of: an acrylic, an epoxy resin, and a polyester resin.