# Patent

## Title
Package structure

## Abstract

A chip packaging structure includes a flexible circuit board, a first built-up structure, a second built-up structure, and a first solder resist layer. The flexible circuit board defines a bent area and a laminated area. The flexible circuit board includes a first dielectric layer. The first dielectric layer includes a first conductive pattern, a bearing layer opposite to the first conductive pattern and corresponding to the laminated area. The first built-up structure is located on the first conductive pattern and corresponds to the laminated area, and includes a second dielectric layer and a second conductive pattern electrically connected with the first conductive pattern. The second built-up structure is located on the bearing layer and corresponds to the laminated area, and includes a third dielectric layer and a third conductive pattern electrically connected with the first conductive pattern. The first solder resist layer covers the second conductive pattern.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a divisional application of patent application Ser. No. 14/857020, filed on Sep. 19, 2015, assigned to the same assignee, which is based on and claims priority to Chinese Patent Application Number 201410791267.7 filed on Dec. 19, 2014, the contents of which are incorporated by reference herein.


FIELD
The subject matter herein generally relates to a chip packaging structure and a method for manufacturing a package structure.
BACKGROUND
A package structure includes a package substrate and a chip packaged on the package substrate. The package substrate includes a package surface and an electrical connection surface opposite to the package surface. The chip is packaged on the package surface. The electrical connection surface includes a plurality of electrical contact pads. The electrical contact pads electrically connect the package structure and an external device.



BRIEF DESCRIPTION OF THE DRAWINGS
Implementations of the present technology will now be described, by way of example only, with reference to the attached figures.
FIG. 1 is a flow chart of an embodiment of a method for manufacturing a chip packaging structure.
FIGS. 2-20 each are a cross-sectional view of an embodiment of processes in the manufacture of a packaging structure.
FIG. 21 is a cross-sectional view of a state of use of the package structure of FIG. 20.



DETAILED DESCRIPTION OF EMBODIMENTS
It will be appreciated that for simplicity and clarity of illustration, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. The description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure.
Several definitions that apply throughout this disclosure will now be presented.
The term “substantially” is defined to be essentially conforming to the particular dimension, shape, or other feature that the term modifies, such that the component need not be exact. For example, “substantially cylindrical” means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series, and the like.
The present disclosure is described in relation to a method for manufacturing a package structure. The method comprises providing a flexible circuit board, and defining a bent area and a laminated area. A first dielectric layer, a first conductive pattern, and a bearing layer are applied, wherein the first conductive pattern and the bearing layer are located at opposite sides of the first dielectric layer, the first conductive pattern comprises a connection terminal located at an end of the bent area away from the laminated area, and the bearing layer corresponds to the laminated area. A second dielectric layer and a second conductive pattern are thus formed on the first conductive pattern, and a third dielectric layer and a third conductive pattern are formed on the bearing layer, wherein a plurality of first conductive holes are defined in the second dielectric layer. The second conductive pattern and the first conductive pattern are electrically connected with each other via the first conductive holes, and a plurality of second conductive holes are defined in the third dielectric layer. The second conductive holes are separated from the bearing layer, and the third conductive pattern and the first conductive pattern are electrically connected with each other via the second conductive holes. The second and third dielectric layers, and the second and third conductive patterns correspond to the laminated area. A first solder resist layer is formed on the second conductive layer, wherein the first solder resist layer defines a plurality of openings, and a portion of the second conductive pattern is exposed from the openings, thus defining a plurality of first pads.
FIG. 1 illustrates a flowchart of an example method 400 presented in accordance with an example embodiment. The example method 400 for manufacturing a package structure (shown in FIG. 19) is provided by way of an example, as there are a variety of ways to carry out the method. Each block shown in FIG. 1 represents one or more processes, methods, or subroutines, carried out in the exemplary method 400. Additionally, the illustrated order of blocks is by example only and the order of the blocks can change. The exemplary method 400 can begin at block 401.
At block 401, providing a flexible circuit board 10.
FIG. 2 illustrates that the flexible circuit board 10 defines a bent area 11 and a laminated area 12. The laminated area 12 connects with the bent area 11. The flexible circuit board 10 includes a first dielectric layer 13, a first conductive pattern 14, and a bearing layer 15 vertically stacked. The first conductive pattern 14 and the bearing layer 15 are located at opposite sides of the first dielectric layer 13. The first dielectric layer 13 includes a first surface 131 and a second surface 132. The first and second surfaces 131 and 132 are opposite to each other. The first conductive pattern 14 is located at the first surface 131. The first conductive pattern 14 includes a connection terminal 141. The connection terminal 141 is located at an end of the bent area 11 away from the laminated area 12. The connection terminal 141 is configured to electrically connect with a first external device 200. The bearing layer 15 is located at the second surface 132. The bearing layer 15 corresponds to the laminated area 12. A portion of the bearing layer 15 extends to the bent area 11. The bearing layer 15 is configured to provide rigid support. The bearing layer 15 defines a plurality of first openings 151. A portion of the first dielectric layer 13 is exposed from the first openings 151.
In at least one embodiment, the flexible circuit board 10 can be obtained in the following way.
A flexible substrate 101 is provided. FIG. 3 illustrates that the flexible substrate 101 defines a bent area 11 and a laminated area 12. In at least one embodiment, the flexible substrate 101 is a double-sided substrate. The flexible substrate 101 includes a first dielectric layer 13, a first copper layer 140, and an original bearing layer 150. The first dielectric layer 13 is made of insulating materials with certain flexibility, such as polyimide and polyester. The first dielectric layer 13 includes a first surface 131 and a second surface 132 opposite to the first surface 131. The first copper layer 140 is located at the first surface 131. The original bearing layer 150 is located at the second surface 132. A thickness of the original bearing layer 150 is greater than a thickness of the first copper layer.
The first conductive pattern 14 and the bearing layer 15 are formed by selectively removing the first copper layer 140 and the original bearing layer 150 respectively via image transferring and etching process. The original bearing layer 150 corresponding to the bent area 11 is removed, and a plurality of first openings 151 are defined in the original bearing layer 150 to correspond to the laminated area 12.
In another embodiment, the flexible circuit board 10 can be obtained in following way.
Referring to FIGS. 3 and 4, a flexible substrate 102 is provided. The flexible substrate 102 defines a bent area 11 and a laminated area 12. In at least one embodiment, the flexible substrate 102 is a single-sided substrate. The flexible substrate 102 includes a first dielectric layer 13 and a first copper layer 140. The first dielectric layer 13 is made of flexible insulating materials, such as polyimide and polyester. The first dielectric layer 13 includes a first surface 131 and a second surface 132 opposite to the first surface 131. The first copper layer 140 is located at the first surface 131.
Referring to FIGS. 4 and 5, a first conductive pattern 14 is formed by treating the first copper layer 140 via image transferring and etching process.
FIG. 6 illustrates that a bearing layer 15 is provided. The bearing layer 15 defines a plurality of first openings 151. The shape and size of the bearing layer 15 correspond to the shape and size of the laminated area 12.
FIG. 2 illustrates that the bearing layer 15 is laminated on the second surface 132 and corresponds to the laminated area 12.
At block 402, first and second cover layers 16 and 17 are formed.
FIG. 7 illustrates that the first cover layer 16 is formed on the first conductive pattern 14. The first cover layer 16 covers the first conductive pattern 14 and the first dielectric layer 13 exposed from the first conductive pattern 14. The first cover layer 16 defines a plurality of second openings 161. The connection terminal 141 is exposed from the second openings 161. The second cover layer 17 is formed on the bearing layer 15. The second cover layer 17 covers the bearing layer 15, the first dielectric layer 13 exposed from the first openings 151, and the first dielectric layer 13 corresponding to the bent area 11. The first and second cover layers 16 and 17 are configured to protect the first conductive pattern 14, the dielectric layer 13, and the bearing layer 15. In other embodiments, the block 402 can be omitted.
At block 403, a second dielectric layer 21, a second conductive pattern 22, a third dielectric layer 31, and a third conductive pattern 32 are formed.
FIG. 8 illustrates that the second dielectric layer 21 is formed on the first cover layer 16. The second conductive pattern 22 is formed on the second dielectric layer 21. That is, the second dielectric layer 21 is located between the first cover layer 16 and the second conductive pattern 22. A plurality of first conductive holes 211 is defined in the second dielectric layer 21 to electrically connect the first conductive pattern 14 and the second conductive pattern 22. The third dielectric layer 31 is formed on the second cover layer 17. The third conductive pattern 32 is formed on the third dielectric layer 31. That is, the third dielectric layer 31 is located between the second cover layer 17 and the third conductive pattern 32. A plurality of second conductive holes 311 is defined to electrically connect the third conductive pattern 32 and the first conductive pattern 14. The second and third dielectric layers 21, 31 can be made of flexible insulating materials such as polyimide and polyester, or be made of rigid insulating materials such as phenol-formaldehyde resin, epoxy resin, and fiber glass. The second dielectric layer 21, the second conductive pattern 22, the third dielectric layer 31, and the third conductive pattern 32 correspond to the laminated area 12. The second conductive holes 311 run through the third dielectric layer 31, the second cover layer 17, and the first dielectric layer 13. The second conductive holes 311 correspond to the first openings 151. Each second conductive hole 311 runs through a first opening 151 and is separated from the bearing layer 15 by the second cover layer 17.
In at least one embodiment, the second dielectric layer 21, the second conductive pattern 22, the third dielectric layer 31, and the third conductive pattern 32 can be obtained in the following way.
FIG. 9 illustrates that a first built-up structure 20 and a second built-up structure 30 are provided. The first and second built-up structures 20 and 30 correspond to the laminated area 12. The first built-up structure 20 includes a second dielectric layer 21 and a second conductive pattern 22. The second conductive pattern 22 is located at a side of the dielectric layer 21. The second built-up structure 30 includes a third dielectric layer 31 and a third conductive pattern 32. The third conductive pattern 32 is located at a side of the third dielectric layer 31.
FIG. 10 illustrates that the first and second built-up structures 20 and 30 are laminated on the first and second cover layers 16 and 17 respectively. The second dielectric layer 21 is located between the first cover layer 16 and the second conductive pattern 22. The third dielectric layer 31 is located between the second cover layer 17 and the third conductive pattern 32.
FIG. 11 illustrates that a plurality of first and second blind holes 210 and 310 is defined. The first blind holes 210 run through the second conductive pattern 22, the second dielectric layer 21, and the first cover layer 16. A portion of the first conductive pattern 14 is exposed from the first blind holes 210. The second blind holes 310 correspond to the first openings 151. The second blind holes 310 run through the third conductive pattern 32, the third dielectric layer 31, the second cover layer 17, the first openings 151, and the first dielectric layer 13. A portion of the first conductive pattern 14 is exposed from the second blind holes 310.
FIG. 8 illustrates that a plurality of first and second conductive holes 211 and 311 is formed by plating and filling the first and second blind holes 210 and 310 with conductive materials such as copper or silver.
In another embodiment, FIG. 12 illustrates that the second conductive pattern 22 includes a first seed layer 221 and a first plated layer 222. The third conductive pattern 32 includes a second seed layer 321 and a second plated layer 322. In this case, the second dielectric layer 21, the second conductive pattern 22, the third dielectric layer 31, and the third conductive pattern 32 can be obtained in following way.
FIG. 13 illustrates that a second dielectric layer 21 is laminated on the first cover layer 16. A third dielectric layer 31 is laminated on the second cover layer 17. The second dielectric layer 21 covers the first cover layer 16 and the connection terminal 141 exposed from an end of the first cover layer 16. The third dielectric layer 31 covers the second cover layer 17.
FIG. 14 illustrates that a plurality of first and second blind holes 210 and 310 is defined. The first blind holes 210 run through the second dielectric layer 21 and the first cover layer 16. A portion of the first conductive pattern 14 is exposed from the first blind holes 210. The second blind holes 310 run through the third dielectric layer 31, the second cover layer 17, and the first dielectric layer 13. The second blind holes 310 correspond to the first openings 151. The second blind holes 310 are separated from the bearing layer 15 by the second cover layer 17. A portion of the first conductive pattern 14 is exposed from the second blind holes 310.
FIG. 15 illustrates that a first seed layer 221 and a second seed layer 321 are formed. The first seed layer 221 covers the second dielectric layer 21, the walls of the first blind holes 210, and the first conductive pattern 14 exposed from the first blind holes 210. The second seed layer 321 covers the third dielectric layer 31, the walls of the second blind holes 310, and the first conductive pattern 14 exposed from the second blind holes 310.
FIG. 16 illustrates that a first patterned barrier layer 23 and a second patterned barrier layer 33 are formed. The first patterned barrier layer 23 is formed on the first seed layer 221. The first patterned barrier layer 23 entirely covers the first seed layer 221 corresponding to the bent area 11. A portion of the first seed layer 221 is exposed from the first barrier layer 23. The first blind holes 210 are exposed from the first patterned barrier layer 23. The second patterned barrier layer 33 entirely covers the second seed layer 321 corresponding to the bent area 11. A number of The second blind holes 310 are exposed from the second patterned barrier layer 33.
FIG. 17 illustrates that a first plated layer 222 and a second plated layer 322 are formed. The first plated layer 222 is formed on the exposed first seed layer 221 and infills the first blind holes 210 defining a plurality of first conductive holes 211. The second plated layer 322 is formed on the exposed second seed layer 321 and infills the second blind holes 310 defining a plurality of second conductive holes 311.
FIG. 18 illustrates that the first barrier layer 23, the first seed layer 221 which is covered by the first barrier layer 23, the second barrier layer 33, and the second seed layer 321 which is covered by the second barrier layer 33 are removed to form a second conductive pattern 22 and a third conductive pattern 32. Both of the second and third conductive patterns 22 and 32 correspond to the laminated area 12. A portion of the second and third dielectric layers 21 and 31 are exposed from the second and third conductive patterns 22 and 32.
FIG. 12 illustrates that the second dielectric layer 21, the first cover layer 16, the third dielectric layer 31, and the third cover layer 17 corresponding to the bent area 11 are removed by means of routing or laser cutting.
At block 404, a first solder resist layer 40 and a second solder resist layer 50 are formed.
FIG. 19 illustrates that the first solder resist layer 40 is formed on the second conductive pattern 22. The first solder resist layer 40 corresponds to the laminated area 12. The first solder resist layer 40 covers the second conductive pattern 22 and the second dielectric layer 21 exposed from the second conductive pattern 22. A plurality of third openings 41 is defined in the first solder resist layer 40. A portion of the second conductive pattern 22 is exposed from the third openings 41 defining a plurality of first pads 24. The first pads 34 are configured to electrically connect with a chip 60. The second solder resist layer 50 is formed on the third conductive pattern 32. The second solder resist layer 50 corresponds to the laminated area 12. The second solder resist layer 50 covers the third conductive pattern 32 and the third dielectric layer 31 exposed from the third conductive pattern 32. A plurality of fourth openings 51 is defined in the second solder resist layer 50. A portion of the third conductive pattern 32 is exposed from the fourth openings 51 defining a plurality of second pads 34. The second pads 34 are configured to electrically connect with a second external device 300.
At block 405, a chip 60 is mounted on the second conductive pattern 22.
The chip 60 can be a logic chip or a memory chip. FIG. 20 illustrates that the chip 60 includes a plurality of electrode pads 61. Each electrode pad 61 corresponds to a first pad 24. Each electrode pad 61 and a corresponding first pad 24 are electrically connected with each other by a solder ball 70. In at least one embodiment, there is bottom resin 80 infilled in the space between the chip 60, the first solder resist layer 40, and the solder balls 70.
In at least one embodiment, the method for mounting the chip 60 can be as follows.
A solder ball 70 is formed on each first pad 24. The solder balls 70 are protruding from the first solder resist layer 40.
A chip 60, including a plurality of electrode pads 61, is mounted on the second conductive pattern 22. The electrode pads 61 correspond to the solder balls 70. Each electrode pad 61 is electrically connected to a solder ball 70.
Bottom resin 80 is infilled in a space between the chip 60, the second conductive pattern 22, and the solder balls 70.
In other embodiments, before that the first and second solder resist layers 40 and 50 are formed, more dielectric layers and conductive patterns can be formed on the second and third conductive patterns 22 and 32. Each dielectric layer defines a plurality of conductive holes. Each conductive pattern electrically connects to the second or third conductive pattern 22 or 32 via the conductive holes.
FIGS. 20 and 21 illustrate an exemplary embodiment of a package structure 100. The package structure 100 includes a flexible circuit board 10, a first built-up structure 20, a second built-up structure 30, a first solder resist layer 40, and a second resist layer 50.
In at least one embodiment, the flexible circuit board 10 defines a bent area 11 and a laminated area 12 connected with the bent area 11.
The flexible circuit board 10 includes a first dielectric layer 13, a first conductive pattern 14, and a bearing layer 15. The first dielectric layer 13 includes a first surface 131 and a second surface 132. The first and second surfaces 131 and 132 are opposite and substantially parallel to each other. The first conductive pattern 14 is located on the first surface 131. The first conductive pattern 14 extends from the laminated area 12 to the bent area 11. The first conductive pattern 14 includes a connection terminal 141. The connection terminal 141 is located at an end of the beading area 11 away from the laminated area 12. The connection terminal 141 is configured to electrically connect to a first external device 200. The bearing layer 15 is located on the second surface 132. The bearing layer 15 corresponds to the laminated area 12. A thickness of the bearing layer 15 is greater than that of the first conductive pattern 14. The bearing layer 15 is configured to provide a rigid support. The bearing layer 15 defines a plurality of first openings 151. A portion of the first dielectric layer 13 is exposed from the first openings 151.
The flexible circuit board 10 further includes a first cover layer 16 and a second cover layer 17. The first cover layer 16 covers the first conductive pattern 14 and the first dielectric layer 13 exposed from the first conductive pattern 14. The first cover layer 16 defines a plurality of second openings 161. The connection terminal 141 is exposed from the second openings 161. The second cover layer 17 covers the bearing layer 15, the first dielectric layer 13 which is exposed from the first openings 151, and the dielectric layer 13 corresponding to the bent area 11.
The first built-up structure 20 is located on the first cover layer 16, and corresponds to the laminated area 12. The first built-up structure 20 includes a second dielectric layer 21 and a second conductive pattern 22. The second dielectric layer 21 can be made of flexible insulating materials such as polyimide and polyester, or be made of rigid insulating materials such as phenol-formaldehyde resin, epoxy resin, and fiber glass fabric. A plurality of first conductive holes 211 is defined in the second dielectric layer 21. The first conductive holes 211 run through the second dielectric layer 21 and the first cover layer 16. The second conductive pattern 22 and the first conductive pattern 14 are electrically connected with each other via the first conductive holes 211.
The second built-up structure 30 is located on the second cover layer 17 and corresponds to the laminated area 12. The second built-up structure 30 includes a third dielectric layer 31 and a third conductive pattern 32. The third dielectric layer 31 can be made of flexible insulating materials such as polyimide and polyester, or be made of rigid insulating materials such as phenol-formaldehyde resin, epoxy resin, and fiber glass fabric. A plurality of second conductive holes 311 is defined in the third dielectric layer 31. The second conductive holes 311 run through the third dielectric layer 31, the second cover layer 17, and the first dielectric layer 13. The second conductive holes 311 correspond to the first openings 151. The second conductive holes 311 and the bearing layer 15 are separated from each other. The third conductive pattern 32 and the first conductive pattern 14 are electrically connected with each other via the second conductive holes 311.
The first solder resist layer 40 covers the second conductive pattern 22. The first solder resist layer 40 defines a plurality of third openings 41. A portion of the second conductive pattern 22 is exposed from the third openings 41 defining a plurality of first pads 24. The first pads 24 are configured to electrically connect to a chip 60.
The second solder resist layer 50 covers the third conductive pattern 32. The second solder resist layer 50 defines a plurality of fourth openings 51. A portion of the third conductive pattern 32 is exposed from the fourth openings 51 and defines a plurality of second pads 34. The second pads 34 are configured to electrically connect to a second external device 300.
The package structure 100 further includes a chip 60. The chip 60 is mounted on the first solder resist layer 40. The chip 60 includes a plurality of electrode pads 61. The electrode pads 61 correspond to the first pads 24. Each electrode pad 61 and a first pad 24 are electrically connected with each other via a solder ball 70. Bottom resin 80 is infilled in a space between the chip 60, the first solder resist layer 40, and the solder balls 80.
In other embodiments, the package structure 100 can further include more built-up structures. The built-up structures are located between the second conductive pattern 22 and the first solder resist layer 40, or between the third conductive pattern 32 and the second solder resist layer 50. Each built-up structure includes a conductive pattern and a dielectric layer. Each conductive pattern is electrically connected with another via conductive holes defined in each dielectric layer.
The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of a package structure and a method for manufacturing a package structure. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the details, especially in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.

## Claims

1. A package structure comprising:
a flexible circuit board defining a bent area and a laminated area and comprising:
a first dielectric layer;
a first conductive pattern located at a side of the first dielectric layer, comprising a connection terminal located at an end of the bent area away from the laminated area;
a bearing layer located at a side of the first dielectric layer opposite to the first conductive pattern, corresponding to the laminated area; and
a first built-up structure located on the first conductive pattern and corresponding to the laminated area, the first built-up structure comprising a second dielectric layer and a second conductive pattern electrically connected with the first conductive pattern via first conductive holes in the second dielectric layer;
a second built-up structure located on the bearing layer and corresponding to the laminated area, the second built-up structure comprising a third dielectric layer and a third conductive pattern electrically connected with the first conductive pattern via second conductive holes in the third dielectric layer; wherein the second dielectric layer, the third dielectric layer, the second conductive pattern, and the third conductive pattern correspond only to the laminated area; and
a first solder resist layer covering the second conductive pattern and defining a plurality of openings, a portion of the second conductive pattern exposed from the openings defining a plurality of first pads.

2. The package structure of claim 1, further comprising a second solder resist layer, wherein the second solder resist layer covers third conductive pattern, the second solder resist layer defines a plurality of openings, a portion of the third conductive pattern exposed from the openings defines a plurality of second pads.

3. The package structure of claim 1, further comprising a first cover layer and a second cover layer, wherein the first cover layer covers the first conductive pattern, the first cover layer defines a plurality of openings, the connection terminal is exposed from the openings, the second cover layer cover the bearing layer, the first dielectric layer exposed from the bearing layer, and the first dielectric layer corresponding to the bent area.

4. The package structure of claim 3, wherein the third dielectric layer is located between the second cover layer and the third conductive pattern.

5. The package structure of claim 3, wherein the bearing layer defines a plurality of first openings, the second conductive holes correspond to the first openings, and the second conductive holes and the bearing layer are separated from each other.

6. The package structure of claim 5, further comprising a plurality of first and second blind holes, wherein the first blind holes run through the second conductive pattern, the second dielectric layer, and the first cover layer, a portion of the first conductive pattern is exposed from the first blind holes, the second blind holes run through the third conductive pattern, the third dielectric layer, the second cover layer, the first openings, and the first dielectric layer, a portion of the first conductive pattern is exposed from the second blind holes.

7. The package structure of claim 6, the second blind holes correspond to the first openings respectively.

8. The package structure of claim 1, wherein a thickness of the bearing layer is greater than a thickness of the first conductive pattern.

9. The package structure of claim 1, wherein the first dielectric layer is made of flexible insulating materials.

10. The package structure of claim 1, further comprising a chip on the first solder resist layer, wherein the chip comprises a plurality of electrode pads, and each of the electrode pads corresponds to and electrically connects to one of the first pads.