Electronic component integrated module and method for fabricating the same

Abstract

The electronic component integrated module includes a wiring board; an electronic component provided on the wiring board; solder for electrically connecting the electronic component onto the wiring substrate; and an encapsulating resin for encapsulating the electronic component and the solder. The average linear thermal expansion coefficient α of the encapsulating resin, which is calculated by using the glass transition temperature of the encapsulating resin, a linear thermal expansion coefficient α1 obtained at a temperature lower than the glass transition temperature, a linear thermal expansion coefficient α2 obtained at a temperature exceeding the glass transition temperature, room temperature, and a peak temperature of reflow packaging of the electronic component integrated module, is not less than 17×106/° C. and not more than 110×10−6/° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an electronic component integrated module according to an embodiment of the invention.

FIG. 2 is a cross-sectional view taken on line II-II of FIG. 1

FIG. 3 is a flowchart for showing exemplified fabrication procedures for the electronic component integrated module of the embodiment.

FIG. 4 is a flowchart for showing fabrication procedures for the electronic component integrated module according to a modification of the embodiment.

FIG. 5A is a cross-sectional view for showing a state of a comparative electronic component integrated module attained during the secondary packaging reflow.

FIG. 5B is a cross-sectional view for showing a state of the comparative electronic component integrated module attained after the secondary packaging reflow.

Claims

1. An electronic component integrated module comprising: a wiring board;an electronic component provided on said wiring board;solder for electrically connecting said electronic component onto said wiring board; andan encapsulating resin provided on said wiring board for encapsulating said electronic component and said solder,wherein an average linear thermal expansion coefficient α of said encapsulating resin calculated by the following Formula 1 is not less than 17×10−6/° C. and not more than 110×10−6/° C.: α={α1×(Tg−Tr)+α2×(Tp−Tg)}/(Tp−Tr)  Formula 1wherein α1 indicates a linear thermal expansion coefficient of said encapsulating resin obtained at a temperature lower than a glass transition temperature thereof; α2 indicates a linear thermal expansion coefficient of said encapsulating resin obtained at a temperature exceeding the glass transition temperature; Tg indicates the glass transition temperature of said encapsulating resin; Tr indicates room temperature; and Tp indicates a peak temperature of packaging of said electronic component integrated module.

2. The electronic component integrated module of claim 1, wherein said electronic component is a surface mount electronic component in the shape of a chip and is at least one of a capacitor, a resistor and a coil.

3. The electronic component integrated module of claim 1, wherein said encapsulating resin includes an inorganic filler, anda content of said inorganic filler in said encapsulating resin is not less than 70% and not more than 90% based on a mass thereof.

4. The electronic component integrated module of claim 3, wherein said inorganic filler is at least one of Al2O3, MgO, BN, AlN and SiO2.

5. The electronic component integrated module of claim 1, wherein said encapsulating resin has a viscosity not less than 50 Pa·s and not more than 100 Pa·s and has a thixotropic ratio not less than 0.8 and not more than 1.5 at a temperature of 25° C.

6. The electronic component integrated module of claim 1, wherein said encapsulating resin includes at least one of an epoxy resin and a silicone resin.

7. The electronic component integrated module of claim 1, wherein said wiring board is an organic wiring board.

8. The electronic component integrated module of claim 1, wherein said wiring board is a ceramic wiring board.

9. A method for fabricating an electronic component integrated module, comprising: a connecting step of electrically connecting an electronic component onto a wiring board with solder;a cleaning step of generating plasma by using a gas including at least one of oxygen and argon and cleaning a surface of said wiring board with the plasma; andan encapsulating step of providing an encapsulating resin on said wiring board for encapsulating said electronic component and said solder,wherein an average linear thermal expansion coefficient α calculated by the following Formula 1 of said encapsulating resin used in the encapsulating step is not less than 17×10−6/° C. and not more than 110×10−6/° C.: α={α1×(Tg−Tr)+α2×(Tp−Tg)}/(Tp−Tr)  Formula 1wherein α1 indicates a linear thermal expansion coefficient of said encapsulating resin obtained at a temperature lower than a glass transition temperature thereof; α2 indicates a linear thermal expansion coefficient of said encapsulating resin obtained at a temperature exceeding the glass transition temperature; Tg indicates the glass transition temperature of said encapsulating resin; Tr indicates room temperature; and Tp indicates a peak temperature of packaging of said electronic component integrated module.

10. The method for fabricating an electronic component integrated module of claim 9, wherein said encapsulating resin is provided on said wiring board by a printing method.

11. The method for fabricating an electronic component integrated module of claim 9, wherein said electronic component and said solder are encapsulated under a reduced pressure in the encapsulating step.

12. The method for fabricating an electronic component integrated module of claim 9, wherein a base substrate having, on a surface thereof, a plurality of regions each including an interconnect in a given shape is used as said wiring board in the connecting step for electrically connecting said electronic component to said interconnect in the given shape in each of said plurality of regions, andthe method further includes, after the encapsulating step, a dividing step of dividing said base substrate into said plurality of regions for obtaining a plurality of electronic component integrated modules from one base substrate.