Package structure and its fabrication method

1. A package structure comprising:

a first polymer layer with a first surface;

a second polymer layer with a second surface on the first polymer layer;

a circuit device with a third surface and an opposite fourth surface, the circuit device disposed on the second polymer layer and with multiple metal pads on the fourth surface;

a first high-filler dielectric layer enclosing the circuit device and the second polymer layer and covering the first polymer layer;

a first conductive wiring formed on the first high-filler dielectric layer;

a first conductive passage formed in the first high-filler dielectric layer and connecting the first conductive wiring to the metal pad;

a second high-filler dielectric layer enclosing the first conductive wiring and covering the first high-filler dielectric layer; and

a second conductive passage formed in the second high-filler dielectric layer and connecting the first conductive wiring to an external circuit;

wherein the first surface is larger than the second surface, and the second surface and the third surface are identical in area size.

2. The package structure of claim 1 , wherein the first polymer layer comprises epoxy-based resin, and the second polymer layer comprises epoxy-based resin.

3. The package structure of claim 1 , wherein the first high-filler dielectric layer comprises a first molding compound, and the second high-filler dielectric layer comprises a second molding compound.

4. The package structure of claim 1 , wherein the circuit device comprises a semiconductor chip or an electronic component.

5. The package structure of claim 1 , further comprising:

a second conductive wiring formed on the second conductive passage and the second high-filler dielectric layer;

a protective layer enclosing the second conductive wiring and covering the second high-filler dielectric layer; and

a third conductive passage formed in the protective layer and connecting the second conductive wiring to an external circuit.

6. The package structure of claim 5 , wherein the second conductive passage comprises a metal pillar.

7. A method for fabricating a package structure, comprising steps of:

(A) providing a carrier and a plurality of circuit devices, the carrier having a first surface, each of the circuit devices having a second surface and an opposite third surface, and each of the circuit devices with multiple metal pads on the third surface;

(B) forming a first polymer layer on the carrier, while enabling the first polymer layer to completely cover the first surface of the carrier;

(C) forming a second polymer layer on all of the circuit devices, while enabling the second polymer layer to completely cover the second surfaces of the circuit devices;

(D) arranging the circuit devices on the carrier, while enabling the second polymer layer to be adhered to the first polymer layer;

(E) forming a first high-filler dielectric layer on the carrier, while enabling the first high-filler dielectric layer to cover the circuit devices;

(F) forming a first conductive passage in the first high-filler dielectric layer, and forming a first conductive wiring on the first conductive passage, while enabling the first conductive passage to connect the first conductive wiring to the metal pad;

(G) forming a second high-filler dielectric layer on the first high-filler dielectric layer, while enabling the second high-filler dielectric layer to enclose the first conductive wiring and cover the first high-filler dielectric layer;

(H) forming a second conductive passage in the second high-filler dielectric layer, while enabling the second conductive passage to be connected to the first conductive wiring;

(I) removing the carrier to get a semi-finished package structure containing the circuit devices; and

(F) dividing the semi-finished package structure into a plurality of package structures, while enabling each of the package structures has one of the circuit devices.

8. The method of claim 7 , wherein the first polymer layer is formed by pressing or coating and then baked in step (B).

9. The method of claim 7 , wherein the second polymer layer is formed by pressing, coating or printing and then baked in step (C).

10. The method of claim 7 , wherein the first conductive passage is formed by following steps:

laser drilling a through opening in the first high-filler dielectric layer on the metal pads of the circuit devices; and

filling up the through opening with conducting material by electroplating.