# Patent

## Title
Fabrication method of embedded chip substrate

## Abstract

An embedded chip substrate includes a first insulation layer, a core layer, a chip, a second insulation layer, a first circuit layer, and a second circuit layer. The core layer disposed on the first insulation layer has an opening that exposes a portion of the first insulation layer. The chip is adhered into a recess constructed by the opening and the first insulation layer. The second insulation layer is disposed on the core layer for covering the chip. The first circuit layer is disposed at the outer side of the first insulation layer located between the first circuit layer and the core layer. The second circuit layer is disposed at the outer side of the second insulation layer located between the second circuit layer and the core layer. The first circuit layer is electrically connected to the second circuit layer that is electrically connected to the chip.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 13/564,421, filed Aug. 1, 2012, which is a divisional application of U.S. patent application Ser. No. 12/500,841, filed on Jul. 10, 2009, now abandoned, which claims the priority benefit of Taiwan Application No. 97127864, filed on Jul. 22, 2008. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.


BACKGROUND OF THE INVENTION
Field of the Invention
The present invention generally relates to a fabrication method of a substrate. More particularly, the present invention relates to a fabrication method of an embedded chip substrate.
Description of Related Art
With recent progress of electronic technologies, electronic products that are more user-friendly and with better functions are continuously developed. Further, these products are designed to satisfy requirements for lightness, slimness, shortness, and compactness. In a housing of the electronic product, a circuit board is often disposed for carrying various electronic elements. The electronic elements occupy the carrying area on the circuit board. Hence, when the number of the electronic elements increases, the carrying area on the circuit board is required to be extended. As such, the area occupied by the circuit board is inevitably increased as well, which deteriorates miniaturization of the electronic products. In addition, the circuit boards used in chip packages also encounter the similar issue.
SUMMARY OF THE INVENTION
The present invention further provides a fabrication method of an embedded chip substrate. A chip in the embedded chip substrate formed by conducting said fabrication method does not occupy a carrying area of a circuit board.
In the present invention, a fabrication method of an embedded chip substrate is provided hereinafter. First, a core layer that has an opening is provided. Next, a first insulation layer and a first conductive layer are provided. The first conductive layer is disposed on the first insulation layer. The core layer is then disposed on the first insulation layer that is located between the core layer and the first conductive layer. After that, a chip is adhered into a recess formed by the opening and the first insulation layer. Thereafter, a second insulation layer and a second conductive layer are provided. The second conductive layer is disposed on the second insulation layer. The second insulation layer is then disposed on the core layer. The second insulation layer is located between the core layer and the second conductive layer and covers the recess. Afterwards, the first conductive layer, the first insulation layer, the core layer, the second insulation layer, and the second conductive layer are laminated. Next, the first conductive layer and the second conductive layer are respectively patterned, so as to form a first circuit layer and a second circuit layer. The first circuit layer is electrically connected to the second circuit layer, and the second circuit layer is electrically connected to the chip.
In light of the foregoing, the chip is embedded into the circuit board according to the present invention, and therefore the chip does not occupy the carrying area of the circuit board.
In order to make the above and other features and advantages of the present invention more comprehensible, several embodiments accompanied with figures are described in detail below.



BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings constituting a part of this specification are incorporated herein to provide a further understanding of the invention. Here, the drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
FIGS. 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I, 1J, 1K and 1L are schematic cross-sectional flowcharts illustrating a process of manufacturing an embedded chip substrate according to an embodiment of the present invention.
FIGS. 2A and 2B are schematic cross-sectional flowcharts illustrating a process of manufacturing an embedded chip substrate according to another embodiment of the present invention.
FIG. 3 is a schematic cross-sectional flowchart illustrating a process of manufacturing an embedded chip substrate according to still another embodiment of the present invention.
FIGS. 4 and 5 are schematic cross-sectional views illustrating two modifications of the embedded chip substrate depicted in FIG. 1L.



DESCRIPTION OF EMBODIMENTS
FIGS. 1A through 1L are schematic cross-sectional flowcharts illustrating a process of manufacturing an embedded chip substrate according to an embodiment of the present invention. FIGS. 2A and 2B are schematic cross-sectional flowcharts illustrating a process of manufacturing an embedded chip substrate according to another embodiment of the present invention. FIG. 3 is a schematic cross-sectional flowchart illustrating a process of manufacturing an embedded chip substrate according to still another embodiment of the present invention.
First, referring to FIG. 1A, a core layer 10 is provided. The core layer 10 includes a core dielectric layer 12 and two conductive layers 14 that are disposed at opposite sides of the core dielectric layer 12, respectively. The core dielectric layer 12 can be an insulation board. Additionally, in other embodiments that are not depicted in the drawings, a multi-layered board can serve as a substitute for the core dielectric layer 12 of the present embodiment. The multi-layered board can be composed of multiple circuit layers and multiple insulation layers alternately arranged.
Next, referring to FIG. 1B, the two conductive layers 14 are patterned, respectively, so as to form two core circuit layers 14a. After that, referring to FIG. 1C, an opening 16 is formed on the core layer 10. Here, a method of forming the opening 16 includes performing a routing process, such as a mechanical drilling process, a punching process, or any other appropriate routing processes.
Thereafter, referring to FIG. 1D, a first insulation layer 110 and a first conductive layer 120 are provided. The first conductive layer 120 is disposed on the first insulation layer 110, and a material of the first insulation layer 110 is, for example, a two-state curable compound. In the present embodiment, a resin coated copper (RCC) can be used to form the first insulation layer 110 and the first conductive layer 120. After that, the core layer 10 is disposed on the first insulation layer 110, and the first insulation layer 110 is located between the core layer 10 and the first conductive layer 120. Besides, the opening 16 and the first insulation layer 110 together form a recess R.
Afterwards, referring to FIG. 1E, a chip 130 is adhered into the recess R. In the present embodiment, the chip 130 is adhered into the recess R by disposing a bottom adhesion layer 142 on the first insulation layer 110, so as to adhere the chip 130 onto the first insulation layer 110. Additionally, a side wall adhesion layer 144 is formed between the inner side wall of the recess R and the side wall of the chip 130, so as to adhere the chip 130 to the inner side wall of the recess R. Besides, in other embodiments, the chip 130 can also be adhered into the recess R only by means of the bottom adhesion layer 142 (as shown in FIG. 2A) or the side wall adhesion layer 144 (as shown in FIG. 3).
A material of the bottom adhesion layer 142 is, for example, polyimide (PI), or any other appropriate adhesive materials. By contrast, a material of the side wall adhesion layer 144 is, for example, epoxy resin, or any other appropriate adhesive materials.
Next, referring to FIG. 1F, a second insulation layer 150 and a second conductive layer 160 are provided. The second conductive layer 160 is disposed on the second insulation layer 150. In the present embodiment, the RCC can be used to form the second insulation layer 150 and the second conductive layer 160. The second insulation layer 150 is then disposed on the core layer 10. Here, the second insulation layer 150 is located between the core layer 10 and the second conductive layer 160 and covers the recess R.
After that, referring to FIG. 1G, the first conductive layer 120, the first insulation layer 110, the core layer 10, the second insulation layer 150, and the second conductive layer 160 are laminated. Besides, the first insulation layer 110 can be heated during the lamination. Since the first insulation layer 110 can be made of the two-stage curable compound, a portion of the first insulation layer 110 overflows between the side wall of the chip 130 and the inner side wall of the recess R.
Thereby, no air or moisture would exist between the side wall of the chip 130 and the inner side wall of the recess R, such that an occurrence of a popcorn effect can be avoided. Moreover, a material of the second insulation layer 150 can also include the two-stage curable compound, which is conducive to filling up the space between the side wall of the chip 130 and the inner side wall of the recess R.
According to other embodiments, when the chip 130 is adhered into the recess R only by means of the bottom adhesion layer 142 (as shown in FIG. 2A), the lamination of the first conductive layer 120, the first insulation layer 110, the core layer 10, the second insulation layer 150, and the second conductive layer 160 and the heating of the first insulation layer 110 allow the space between the side wall of the chip 130 and the inner side wall of the recess R to be filled with a portion of the first insulation layer 110 (as shown in FIG. 2B). As such, it is not necessary to fill the space between the side wall of the chip 130 and the inner side wall of the recess R with other fillers for preventing the occurrence of the popcorn effect.
After that, referring to FIG. 1H, a plurality of conductive blind vias B penetrating the second insulation layer 150 are formed in the present embodiment, so as to electrically connect the chip 130 to the second conductive layer 160. Next, referring to FIG. 1I, the first conductive layer 120 and the second conductive layer 160 are respectively patterned, so as to form a first circuit layer 122 and a second circuit layer 162.
Referring to FIG. 1J, a plurality of conductive through holes T penetrating the second insulation layer 150, the core layer 10, and the first insulation layer 110 are then formed in the present embodiment, so as to electrically connected the first circuit layer 122 to the second circuit layer 162.
Thereafter, referring to FIG. 1K, in the present embodiment, a build-up structure 170 can be further formed at the outer side of the first insulation layer 110 and the outer side of the second insulation layer 150, respectively. A plurality of solder pads 172 are respectively disposed at the outer sides of the build-up structures 170. Next, referring to FIG. 1L, a solder mask layer 180 is formed on the build-up structures 170, respectively, so as to expose the corresponding solder pads 172. To avoid the surfaces of the solder pads 172 from being oxidized, an electrical connection layer 190 can then be formed on the solder pads 172. Here, the electrical connection layer 190 is, for example, a Ni/Au composite layer.
The structure of the embedded chip substrate in FIG. 1L is elaborated hereinafter.
FIGS. 4 and 5 are schematic cross-sectional views illustrating two modifications of the embedded chip substrate depicted in FIG. 1L.
As shown in FIG. 1L, an embedded chip substrate 200 of the present embodiment includes a first insulation layer 110, a core layer 10, a chip 130, a second insulation layer 150, a first circuit layer 122, and a second circuit layer 162. The first insulation layer 110 is made of a two-stage curable compound, for example.
The core layer 10 is disposed on the first insulation layer 110 and has an opening 16 that exposes a portion of the first insulation layer 110. The opening 16 and the first insulation layer 110 together form a recess R where the chip 130 is adhered. In the present embodiment, a bottom adhesion layer 142 is disposed between the chip 130 and the first insulation layer 110, and a side wall adhesion layer 144 is disposed between the inner side wall of the recess R and the side wall of the chip 130, so as to adhere the chip 130 into the recess R.
Besides, referring to FIG. 4, in other embodiments, the chip 130 can be adhered into the recess R only by means of the bottom adhesion layer 142. Note that the first insulation layer 110 can be extended into the space between the inner side wall of the recess R and the side wall of the chip 130, and therefore it is not necessary to fill the space with other fillers for preventing the occurrence of the popcorn effect. Moreover, the material of the second insulation layer 150 can also include the two-stage curable compound, and thus the second insulation layer 150 can also be extended into the space between the inner side wall of the recess R and the side wall of the chip 130 (not shown). Besides, referring to FIG. 5, in other embodiments, the chip 130 can be adhered into the recess R only by means of the side wall adhesion layer 144.
As shown in FIG. 1L, the second insulation layer 150 is disposed on the core layer 10 for covering the chip 130. In addition, the material of the second insulation layer 150 can include the two-stage curable compound. The first circuit layer 122 is disposed at the outer side of the first insulation layer 110, and the first insulation layer 110 is located between the first circuit layer 122 and the core layer 10. The second circuit layer 162 is disposed at the outer side of the second insulation layer 150, and the second insulation layer 150 is located between the second circuit layer 162 and the core layer 10.
In the present embodiment, the first circuit layer 122 and the second circuit layer 162 can be electrically connected to each other through a plurality of conductive through holes T penetrating the second insulation layer 150, the core layer 10, and the first insulation layer 110. The second circuit layer 162 and the chip 130 can be electrically connected to each other through a plurality of conductive blind vias B penetrating the second insulation layer 150.
Additionally, in the present embodiment, a build-up process can be performed at the outer side of the second insulation layer 150 and the outer side of the first insulation layer 110 based on actual demands. According to the present embodiment, a build-up structure 170 is formed respectively at the outer side of the second insulation layer 150 and the outer side of the first insulation layer 110, and a plurality of solder pads 172 are formed at the outer side of each of the built-up structures 170. Moreover, a solder mask layer 180 is formed respectively at the outer sides of the two build-up structures 170 in the present embodiment, and each of the solder mask layers 180 exposes the corresponding solder pads 172.
To avoid the surfaces of the solder pads 172 from being oxidized, an electrical connection layer 190 can be further formed on each of the solder pads 172. Here, the electrical connection layer 190 is, for example, a Ni/Au composite layer.
Based on the above, the chip is embedded into the circuit board according to the present invention, and therefore the chip does not occupy the carrying area on the circuit board. Further, in the aforesaid embodiments, the first insulation layer can be made of the two-stage curable compound. Thus, when the first conductive layer, the first insulation layer, the core layer, the second insulation layer, and the second conductive layer are laminated, the first insulation layer can be heated, such that the first insulation layer overflows between the side wall of the chip and the inner side wall of the recess. Thereby, no air or moisture would exist between the side wall of the chip and the inner side wall of the recess, so as to prevent the occurrence of the popcorn effect.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.

## Claims

1. An embedded chip substrate, comprising:
a dielectric layer defining an opening having an inner side wall;
a first circuit layer disposed over the dielectric layer;
a second circuit layer disposed over the dielectric layer on a side of the dielectric layer opposite to the first circuit layer;
a conductive through hole extending from a top surface of the dielectric layer to a bottom surface of the dielectric layer;
a first insulation layer disposed over the first circuit layer;
a second insulation layer disposed over the second circuit layer;
a chip having a side wall, the chip adhered in a recess formed by the opening and the second insulation layer;
a plurality of first vias in the first insulation layer;
a third circuit layer disposed over the first insulation layer and electrically connected to the chip through the first vias; and
a fourth circuit layer disposed over the second insulation layer, the fourth circuit layer electrically connected to the first circuit layer through the conductive through hole;
wherein the first insulation layer extends into a space between the inner side wall of the opening and the side wall of the chip.

2. The embedded chip substrate as claimed in claim 1, further comprising:
a bottom adhesion layer disposed on the second insulation layer in the recess and located between the chip and the second insulation layer.

3. The embedded chip substrate as claimed in claim 1, further comprising:
a side wall adhesion layer disposed between the inner side wall of the opening and the side wall of the chip.

4. The embedded chip substrate as claimed in claim 1, wherein the conductive through hole further extends through the first insulation layer and the second insulation layer.

5. The embedded chip substrate as claim 1, wherein the dielectric layer is a multi-layered board.

6. The embedded chip substrate as claim 1, wherein the second insulation layer extends into the space between the inner side wall of the opening and the side wall of the chip.

7. The embedded chip substrate as claimed in claim 1, wherein a material of the first insulation layer comprises a two-stage curable compound in a cured stage.

8. The embedded chip substrate as claimed in claim 1, wherein a material of the second insulation layer comprises a two-stage curable compound in a cured stage.