阅读说明：本技术 线路板组件、感光组件、摄像模组及感光组件制作方法 (Circuit board assembly, photosensitive assembly, camera module and photosensitive assembly manufacturing method ) 是由 黄桢 王明珠 赵波杰 田中武彦 陈振宇 郭楠 于 2018-08-01 设计创作，主要内容包括：本发明提供了一种感光组件,包括：感光芯片；软板,其具有与所述感光区域对应的通孔,所述软板具有多个软板电极；以及再布线层,其包括：填充层,其形成于所述软板表面；金属柱,其形成于所述软板电极表面,并被所述填充层覆盖；再布线层走线,其被所述填充层覆盖；以及多个再布线层电极,其暴露在所述填充层外部,并通过所述再布线层走线以及所述金属柱与所述软板电极导通；其中,所述感光芯片附接于所述再布线层,并且所述多个再布线层电极分别与感光芯片的多个芯片电极一一对应地接触并导通。本发明还提供了相应的线路板组件、摄像模组和感光组件制作方法。本发明可以实现摄像模组感光芯片的高密度封装；可以实现高I/O数的封装。(The invention provides a photosensitive assembly, comprising: a photosensitive chip; a soft plate having a through hole corresponding to the photosensitive region, the soft plate having a plurality of soft plate electrodes; and a rewiring layer including: the filling layer is formed on the surface of the soft board; the metal column is formed on the surface of the flexible board electrode and is covered by the filling layer; a rewiring layer routing covered by the filling layer; and a plurality of rewiring layer electrodes exposed outside the filling layer and conducted with the flexible board electrodes through the rewiring layer wiring and the metal posts; the photosensitive chip is attached to the rewiring layer, and the rewiring layer electrodes are respectively in one-to-one corresponding contact with and conducted with the chip electrodes of the photosensitive chip. The invention also provides a corresponding circuit board assembly, a camera module and a photosensitive assembly manufacturing method. The invention can realize the high-density packaging of the photosensitive chip of the camera module; high I/O count packages can be realized.)

1. A photosensitive assembly, comprising:

the device comprises a photosensitive chip, a first electrode, a second electrode and a third electrode, wherein the photosensitive chip is provided with a photosensitive area and a non-photosensitive area surrounding the photosensitive area, and the non-photosensitive area is provided with a plurality of chip electrodes;

a soft plate having a through hole corresponding to the photosensitive region, the soft plate having a plurality of soft plate electrodes; and

a rewiring layer comprising:

the filling layer is formed on the surface of the soft board;

the metal column is formed on the surface of the flexible board electrode and is covered by the filling layer;

a rewiring layer routing covered by the filling layer; and

the rewiring layer electrodes are exposed outside the filling layer and are conducted with the flexible board electrodes through the rewiring layer routing wires and the metal columns;

wherein the photosensitive chip is attached to the rewiring layer, and the rewiring layer electrodes are in one-to-one contact with and electrically connected to the chip electrodes, respectively.

2. A photosensitive assembly according to claim 1, wherein said rewiring layer electrode is closer to said through hole than said flexible board electrode; the area of the rewiring layer electrode is smaller than that of the flexible printed circuit board electrode.

3. The photosensitive assembly of claim 1 wherein the rewiring layer traces are greater than 20 μm thick.

4. The photosensitive assembly of claim 1, wherein the plurality of redistribution layer electrodes are more densely packed than the plurality of flexible board electrodes; the width of the routing of the rewiring layer is smaller than that of the flexible printed circuit board.

5. A photosensitive assembly according to claim 1, wherein the metal pillar is a copper pillar.

6. A photosensitive assembly according to claim 1, further comprising a metal sheet having a groove, the metal sheet being attached to the rewiring layer surface, and the photosensitive chip being located in the groove.

7. A photosensitive assembly according to claim 1, wherein said rewiring layer has a recess in which said photosensitive chip is located; the photosensitive assembly further comprises a metal sheet attached to the surface of the rewiring layer and covering the photosensitive chip.

8. A photosensitive assembly according to claim 6 or 7, wherein said photosensitive chip is not in contact with said metal sheet.

9. The photosensitive assembly of claim 1 further comprising a molding layer formed on the re-wiring layer and the backside of the photosensitive chip.

10. A photosensitive assembly according to claim 1, wherein said flexible board and said photosensitive chip are respectively located at upper and lower sides of said rewiring layer; or the soft board and the photosensitive chip are positioned on the same side of the rewiring layer.

11. The photosensitive assembly of claim 1, wherein the re-routing layer has a plurality of layers of the re-routing layer traces, wherein each layer of the re-routing layer traces has a thickness greater than 20 μ ι η; and the rewiring layer wiring on different layers is conducted through the metal columns.

12. A circuit board assembly, comprising:

the surface of the soft plate is provided with a plurality of soft plate electrodes; and

a rewiring layer comprising:

the filling layer is formed on the surface of the soft board;

the metal column is formed on the surface of the flexible board electrode and is covered by the filling layer;

a rewiring layer routing covered by the filling layer; and

the rewiring layer electrodes are exposed outside the filling layer and are conducted through the rewiring layer wiring and the metal column to the flexible printed circuit board electrodes;

the sizes and the layouts of the rewiring layer electrodes are suitable for attaching the photosensitive chip based on a reverse pasting process, so that the rewiring layer electrodes are respectively in one-to-one corresponding contact with and conducted with the chip electrodes of the photosensitive chip.

13. The wiring board assembly of claim 12, wherein the rewiring layer electrode is closer to the via than the flex board electrode.

14. The wiring board assembly of claim 12, wherein the area of the rewiring layer electrode is smaller than the area of the flex board electrode.

15. The wiring board assembly of claim 12, wherein the plurality of redistribution layer electrodes are more densely populated than the plurality of flex electrodes.

16. The utility model provides a module of making a video recording which characterized in that includes:

the photosensitive assembly of any one of claims 1 to 11; and

and the optical lens is arranged on the photosensitive assembly.

17. A method for manufacturing a photosensitive assembly is characterized by comprising the following steps:

1) implanting metal columns on the soft plate electrode on the surface of the soft plate;

2) filling an insulating material on the surface of the flexible printed circuit board to form a filling layer with a flat surface, and exposing the implanted metal column in the step 1);

3) manufacturing rewiring layer routing on the surface of the filling layer, wherein the rewiring layer routing is communicated with the metal column;

4) implanting metal columns in partial areas of the routing of the rewiring layer;

5) filling an insulating material on the surface of the filling layer again to enable the filling layer to cover the rewiring layer wiring and expose the implanted metal column in the step 4);

repeating the steps 3) -5) until the wiring of the rewiring layer with the preset number of layers is manufactured, obtaining a complete rewiring layer, and forming a plurality of rewiring layer electrodes on the finally exposed metal columns;

6) and attaching a photosensitive chip to the rewiring layer, wherein the rewiring layer electrodes are respectively in one-to-one corresponding contact with and conducted with the chip electrodes of the photosensitive chip.

18. The method of claim 17, wherein in the steps 2) and 4), the filling layer is formed by a molding process.

19. The method for manufacturing a photosensitive assembly according to claim 17, wherein the step 2) of manufacturing the filling layer comprises:

21) forming a molding layer on the surface of the flexible board through a molding process;

22) grinding the molding layer to make the surface of the molding layer flat and expose the metal column implanted in the step 1).

20. The method for fabricating a photosensitive assembly according to claim 19, wherein in the step 22), the surface of the filling layer is flush with the surface of the metal pillar implanted in the step 1).

21. The method for manufacturing a photosensitive assembly according to claim 17, wherein in the step 5), the manufacturing of the filling layer comprises:

51) forming a molding layer on the surface of the existing filling layer through a molding process;

52) grinding the molding layer to make the surface of the molding layer flat and expose the metal column implanted in the step 4).

22. The method for fabricating a photosensitive assembly according to claim 21, wherein in the step 52), the surface of the filling layer is flush with the surface of the metal pillar implanted in the step 4).

23. The method as claimed in claim 17, wherein in the step 4), the metal pillar regions are determined by alignment calibration.

24. The method for manufacturing a photosensitive assembly according to claim 17, wherein in step 1), the center of the flexible board has no through hole;

after the routing of the rewiring layers with the preset number of layers is finished, before the step 6) is executed, a through hole is formed in the center of the soft board and the center of the rewiring layer formed on the soft board, and the through hole corresponds to a photosensitive area of the photosensitive chip.

25. A method for fabricating a photosensitive assembly according to claim 17, wherein after said step 6), the steps of:

7) and attaching a metal sheet with a groove on the surface of the rewiring layer, so that the photosensitive chip is accommodated in the groove, and the metal sheet is not in contact with the photosensitive chip.

26. A method for fabricating a photosensitive assembly according to claim 17, wherein after said step 6), the steps of:

7) and forming a molding layer on the rewiring layer and the back surface of the photosensitive chip through a molding process.

27. A method for fabricating a photosensitive assembly according to claim 17, wherein said step 3) comprises:

31) forming a seed layer on the surface of the existing filling layer;

32) arranging photoresist on the surface of the seed layer and exposing;

33) developing to manufacture a wiring groove;

34) arranging a metal material in the wiring groove to form rewiring layer wiring;

35) and removing the seed layer and the photoresist which are not attached with the rewiring layer wiring.

28. A method for manufacturing a photosensitive assembly is characterized by comprising the following steps:

1) arranging metal columns on the surface of the carrier plate;

2) filling an insulating material on the surface of the carrier plate to form a filling layer with a flat surface, and exposing the metal columns arranged in the step 1);

3) manufacturing rewiring layer routing on the surface of the filling layer, wherein the rewiring layer routing is communicated with the metal column;

4) implanting metal columns in partial areas of the routing of the rewiring layer;

5) filling an insulating material on the surface of the filling layer again to enable the filling layer to cover the rewiring layer wiring and expose the implanted metal column in the step 4);

repeating the steps 3) -5) until the wiring of the rewiring layer with the preset number of layers is manufactured, obtaining a complete rewiring layer, and forming a plurality of rewiring layer electrodes on the finally exposed metal columns;

6) removing the carrier plate attached to the rewiring layer, attaching a soft board to the rewiring layer, and conducting an electrode of the soft board and a metal column of the rewiring layer; and attaching a photosensitive chip to the rewiring layer, and the rewiring layer electrodes are respectively in one-to-one contact with and conducted to the chip electrodes of the photosensitive chip.

Technical Field

The invention relates to the technical field of optics, in particular to a circuit board assembly, a photosensitive assembly, a camera module and a manufacturing method thereof.

Background

With the rapid development of smart phones and other electronic devices, the demand for miniaturization of camera modules is becoming stronger and stronger as the mobile phone screens are becoming more and more comprehensive.

The camera module generally includes an optical lens assembly and a photosensitive assembly. Wherein the photosensitive assembly generally comprises a circuit board and a photosensitive chip mounted on the circuit board. In the conventional camera module, the photo sensor chip is usually connected to the circuit layer by a "wire bonding" process or a flip chip (i.e., a flip chip) process.

The conventional printed circuit board is limited by current requirements, circuit heating caused by circuit board materials, and the processing capability of the printed circuit board, so that the line width and the line distance of the common printed circuit board are about 70 μm. Correspondingly, the wire width and the wire distance of the traditional circuit board are limited, the factors of the circuit board can be considered when the chip is conducted, the pad distance cannot be further reduced, and the development trend of continuous miniaturization of the chip is deviated. In addition, as the bonding pads of the chip are more and more dense, the pitch is approaching the limit, and in the wire bond process, under the condition that the gold wires are very dense, the interference between the gold wires is easy to occur, thereby causing circuit failure. On the other hand, in the whole manufacturing flow, the wire bond process is followed by a series of steps such as molding, lens holder mounting, etc., which will affect the reliability of the gold wire connection. Furthermore, the gold wire has a certain arc height, so an extra height is usually added to the module to avoid the gold wire, and therefore, the existence of the gold wire may hinder the miniaturization of the module.

Nowadays, some manufacturers adopt flip chip technology to solve a series of problems caused by gold wires. For example, in the flip chip process, because the chip is directly attached to the bottom side of the circuit board, and then the chip is conducted with the circuit board through the gold ball, the conducting length of the circuit board and the photosensitive chip is greatly shortened, the delay is reduced, and the electrical property is effectively improved. On the other hand, the Flip Chip process has high requirements for conduction accuracy and flatness, and a ceramic substrate with high structural strength and insusceptibility to bending needs to be used as a circuit board (i.e., a circuit board), and the Flip Chip process is very expensive. In addition, the process scheme requires that the size and the density of the bonding pads of the circuit board are consistent or basically consistent with those of the photosensitive chip. Generally, due to process limitations, the minimum size of the pads of the circuit board is limited, and the gold ball bump line width is large, such as about 100 um. In order to adapt to the flip chip process, the size of the photosensitive chip bonding pad is difficult to further reduce so as to adapt to the bonding pad size of the circuit board. Therefore, the number of the bonding pads which can be arranged on the photosensitive chip is reduced, or the size of the photosensitive chip is increased due to the increase of the number of the bonding pads, so that the size reduction of the camera module is not facilitated. This is because the higher the pixels of the photosensitive chip, the larger the amount of image data that needs to be output, and more I/O ports are needed to output the data. While a smaller number of pads results in a reduction of I/O ports outputting data. Therefore, the existing flip chip process is not favorable for increasing the number of pixels of the photosensitive chip.

Disclosure of Invention

The present invention aims to provide a solution that overcomes at least one of the drawbacks of the prior art.

According to an aspect of the present invention, there is provided a photosensitive assembly including: the device comprises a photosensitive chip, a first electrode, a second electrode and a third electrode, wherein the photosensitive chip is provided with a photosensitive area and a non-photosensitive area surrounding the photosensitive area, and the non-photosensitive area is provided with a plurality of chip electrodes; a soft plate having a through hole corresponding to the photosensitive region, the soft plate having a plurality of soft plate electrodes; and a rewiring layer including: the filling layer is formed on the surface of the soft board; the metal column is formed on the surface of the flexible board electrode and is covered by the filling layer; a rewiring layer routing covered by the filling layer; and a plurality of rewiring layer electrodes exposed outside the filling layer and conducted with the flexible board electrodes through the rewiring layer wiring and the metal posts; wherein the photosensitive chip is attached to the rewiring layer, and the rewiring layer electrodes are in one-to-one contact with and electrically connected to the chip electrodes, respectively.

Wherein the rewiring layer electrode is closer to the through hole than the flexible board electrode; the area of the rewiring layer electrode is smaller than that of the flexible printed circuit board electrode.

Wherein the thickness of the rewiring layer routing is larger than 20 μm.

Wherein the plurality of re-wiring layer electrodes are higher in density than the plurality of soft plate electrodes; the width of the routing of the rewiring layer is smaller than that of the flexible printed circuit board.

Wherein, the metal column is a copper column.

Wherein the photosensitive assembly further comprises a metal sheet having a groove, the metal sheet is attached to the surface of the rewiring layer, and the photosensitive chip is located in the groove.

The rewiring layer is provided with a groove, and the photosensitive chip is located in the groove; the photosensitive assembly further comprises a metal sheet attached to the surface of the rewiring layer and covering the photosensitive chip.

Wherein, the photosensitive chip is not in contact with the metal sheet.

The photosensitive assembly further comprises a molding layer, and the molding layer is formed on the rewiring layer and the back surface of the photosensitive chip.

The flexible board and the photosensitive chip are respectively positioned on the upper side and the lower side of the rewiring layer; or the soft board and the photosensitive chip are positioned on the same side of the rewiring layer.

The rewiring layer is provided with a plurality of rewiring layer routing lines, wherein the thickness of each rewiring layer routing line is more than 20 micrometers; and the rewiring layer wiring on different layers is conducted through the metal columns.

According to another aspect of the present invention, a circuit board assembly includes: the surface of the soft plate is provided with a plurality of soft plate electrodes; and a rewiring layer including: the filling layer is formed on the surface of the soft board; the metal column is formed on the surface of the flexible board electrode and is covered by the filling layer; a rewiring layer routing covered by the filling layer; and a plurality of rewiring layer electrodes exposed outside the filling layer and conducted to the flexible board electrodes through the rewiring layer wiring and the metal posts; the sizes and the layouts of the rewiring layer electrodes are suitable for attaching the photosensitive chip based on a reverse pasting process, so that the rewiring layer electrodes are respectively in one-to-one corresponding contact with and conducted with the chip electrodes of the photosensitive chip.

Wherein the rewiring layer electrode is closer to the through hole than the flexible board electrode.

Wherein the area of the rewiring layer electrode is smaller than that of the flexible printed circuit board electrode.

Wherein the plurality of re-wiring layer electrodes are higher in density than the plurality of soft plate electrodes.

According to another aspect of the present invention, there is also provided a camera module, including: any of the photosensitive assemblies described above; and an optical lens mounted on the photosensitive assembly.

According to another aspect of the present invention, there is also provided a method for manufacturing a photosensitive assembly, including: 1) implanting metal columns on the soft plate electrode on the surface of the soft plate; 2) filling an insulating material on the surface of the flexible printed circuit board to form a filling layer with a flat surface, and exposing the implanted metal column in the step 1); 3) manufacturing rewiring layer routing on the surface of the filling layer, wherein the rewiring layer routing is communicated with the metal column; 4) implanting metal columns in partial areas of the routing of the rewiring layer; 5) filling an insulating material on the surface of the filling layer again to enable the filling layer to cover the rewiring layer wiring and expose the implanted metal column in the step 4); repeating the steps 3) -5) until the wiring of the rewiring layer with the preset number of layers is manufactured, obtaining a complete rewiring layer, and forming a plurality of rewiring layer electrodes on the finally exposed metal columns; 6) and attaching a photosensitive chip to the rewiring layer, wherein the rewiring layer electrodes are respectively in one-to-one corresponding contact with and conducted with the chip electrodes of the photosensitive chip.

In the step 2) and the step 4), the filling layer is manufactured by adopting a molding process.

In step 2), the manufacturing of the filling layer includes: 21) forming a molding layer on the surface of the flexible board through a molding process; 22) grinding the molding layer to make the surface of the molding layer flat and expose the metal column implanted in the step 1).

In the step 22), the surface of the filling layer is flush with the surface of the implanted metal column in the step 1).

In the step 5), the manufacturing of the filling layer includes: 51) forming a molding layer on the surface of the existing filling layer through a molding process; 52) grinding the molding layer to make the surface of the molding layer flat and expose the metal column implanted in the step 4).

In the step 52), the surface of the filling layer is flush with the surface of the implanted metal column in the step 4).

In the step 4), the area of the implanted metal column is determined by alignment calibration.

In the step 1), the center of the soft board is not provided with a through hole; after the routing of the rewiring layers with the preset number of layers is finished, before the step 6) is executed, a through hole is formed in the center of the soft board and the center of the rewiring layer formed on the soft board, and the through hole corresponds to a photosensitive area of the photosensitive chip.

Wherein, after the step 6), the step is executed again: 7) and attaching a metal sheet with a groove on the surface of the rewiring layer, so that the photosensitive chip is accommodated in the groove, and the metal sheet is not in contact with the photosensitive chip.

Wherein, after the step 6), the step is executed again: 7) and forming a molding layer on the rewiring layer and the back surface of the photosensitive chip through a molding process.

Wherein the step 3) comprises: 31) forming a seed layer on the surface of the existing filling layer; 32) arranging photoresist on the surface of the seed layer and exposing; 33) developing to manufacture a wiring groove; 34) arranging a metal material in the wiring groove to form rewiring layer wiring; 35) and removing the seed layer and the photoresist which are not attached with the rewiring layer wiring.

According to another aspect of the present invention, there is provided another method for manufacturing a photosensitive assembly, including: 1) arranging metal columns on the surface of the carrier plate; 2) filling an insulating material on the surface of the carrier plate to form a filling layer with a flat surface, and exposing the metal columns arranged in the step 1); 3) manufacturing rewiring layer routing on the surface of the filling layer, wherein the rewiring layer routing is communicated with the metal column; 4) implanting metal columns in partial areas of the routing of the rewiring layer; 5) filling an insulating material on the surface of the filling layer again to enable the filling layer to cover the rewiring layer wiring and expose the implanted metal column in the step 4); repeating the steps 3) -5) until the wiring of the rewiring layer with the preset number of layers is manufactured, obtaining a complete rewiring layer, and forming a plurality of rewiring layer electrodes on the finally exposed metal columns; 6) removing the carrier plate attached to the rewiring layer, attaching a soft board to the rewiring layer, and conducting an electrode of the soft board and a metal column of the rewiring layer; and attaching a photosensitive chip to the rewiring layer, and the rewiring layer electrodes are respectively in one-to-one contact with and conducted to the chip electrodes of the photosensitive chip.

Compared with the prior art, the invention has at least one of the following technical effects:

1. the invention can realize the conduction of the circuit board bonding pad/circuit with larger line width to the photosensitive chip with smaller contact, and realize the high-density packaging of the photosensitive chip of the camera module.

2. The invention can realize that the circuit board bonding pad relatively close to the outer side of the optical window is conducted to the chip bonding pad closer to the optical window.

3. The invention can realize that the camera module adopts the conventional printed circuit board to realize the reverse chip technology so as to realize the packaging of high I/O number.

Drawings

Exemplary embodiments are illustrated in referenced figures of the drawings. The embodiments and figures disclosed herein are to be regarded as illustrative rather than restrictive.

FIG. 1 shows a schematic cross-sectional view of a photosensitive assembly according to one embodiment of the invention;

fig. 2 shows a schematic diagram of copper pillars 1023a on the flexible board electrodes 1033 of the flexible board 101 in step S100;

fig. 3 is a schematic diagram illustrating that the surface of the flexible printed circuit board 101 is filled with an insulating material to form a filling layer 1021 with a flat surface in step S200;

FIG. 4 shows a schematic diagram of grinding the filling layer in step S300;

fig. 5 is a schematic diagram illustrating a seed copper layer 1029 formed on the surface of the polished filling layer 1021 in step S400;

fig. 6 is a schematic diagram illustrating fabrication of a rewiring layer trace 1024 based on a seed copper layer in step S500;

fig. 7 is a schematic diagram illustrating copper implantation in a partial area of the rewiring layer trace in step S600;

fig. 8 shows a schematic view of removing the seed copper layer 1029 in step S700;

fig. 9 is a schematic view showing that an insulating material is filled again on the surface of an existing filling layer in step S800;

FIG. 10 shows a schematic view of the step S900 of polishing the filling layer to make its surface flat and expose the copper pillar implanted in the step S600;

fig. 11 is a schematic view showing the formation of a completed re-wiring layer;

fig. 12 is a diagram showing solder resist printing on the surface of the re-wiring layer in step S1600;

fig. 13 shows a schematic view of making a via 1013 at the center of the flexible board and the redistribution layer in step S1700;

fig. 14 shows a schematic view of attaching the photosensitive chip 103 on the surface of the rewiring layer in step S1800;

FIG. 15 shows a schematic view of a photosensitive assembly in which the rewiring layer electrodes are implemented as gold balls;

fig. 16 is a schematic view showing attaching of a steel sheet to the surface of the rewiring layer in step S1900;

fig. 17 shows a schematic view of forming a molding layer on the rewiring layer and the back surface of the photosensitive chip in step S1900;

FIG. 18 shows a schematic view of grinding the molding layer 105 to thin the molding layer;

FIG. 19 shows a schematic view of a photosensitive assembly in another embodiment of the invention.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that the expressions first, second, etc. in this specification are used only to distinguish one feature from another feature, and do not indicate any limitation on the features. Thus, a first body discussed below may also be referred to as a second body without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of an object have been slightly exaggerated for convenience of explanation. The figures are purely diagrammatic and not drawn to scale.

It will be further understood that the terms "comprises," "comprising," "includes," "including," "has," "including," and/or "including," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

As used herein, the terms "substantially," "about," and the like are used as terms of table approximation and not as terms of table degree, and are intended to account for inherent deviations in measured or calculated values that will be recognized by those of ordinary skill in the art.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

FIG. 1 shows a schematic cross-sectional view of a photosensitive assembly according to one embodiment of the invention. Referring to fig. 1, the photosensitive assembly includes: a photosensitive chip 103, a soft board 101, and a rewiring layer 102. Wherein the light sensing chip 103 has a light sensing area 1031 and a non-light sensing area 1032 surrounding the light sensing area 1031, the non-light sensing area 1032 being provided with a plurality of chip electrodes 1033. The plurality of chip electrodes 1033 (which may be alternatively referred to as chip pads) may surround the photosensitive area 1031. The flexible board 101 in the present embodiment may also be referred to as a flexible wiring board (i.e., FPC board). The flexible board has a through hole 1013 corresponding to the photosensitive region, and the flexible board has a plurality of flexible board electrodes. The rewiring layer 102 includes: a filling layer 1021, a metal pillar 1023, a redistribution layer trace 1024, and a plurality of redistribution layer electrodes 1022. Wherein, the filling layer 1021 is formed on the surface (the lower surface in fig. 1) of the soft board 101. The metal posts 1023 are formed on the surface of the flexible board electrode 1014 and covered by the filling layer 1021. The redistribution layer trace 1024 is covered by the filling layer 1021, and a plurality of redistribution layer electrodes 1022 are exposed outside the filling layer 1021 and are electrically connected to the corresponding flexible printed circuit board electrodes 1014 through the redistribution layer trace 1024 and the metal studs 1023. Wherein the photosensitive chip 103 is attached to the rewiring layer 102, and the plurality of rewiring layer electrodes 1022 are respectively in one-to-one contact with and electrically connected to the plurality of chip electrodes 1033. The through hole 1013 may be a light passing hole whose position and size are adapted to the light sensing area 1031 of the light sensing chip 103. The area of the flexible board electrode 1014 may be larger than that of the rewiring layer electrode 1022. The area of the re-wiring layer electrodes 1022 is adapted (e.g., equal or substantially equal) to the area of the chip electrodes 1033. In this embodiment, the flexible board electrode 1014 is located outside the rewiring layer electrode 1022 (i.e., the rewiring layer electrode 1022 is closer to the light-passing hole than the flexible board electrode 1014). In this embodiment, the electrodes may be all metal electrodes.

In the prior art, since the printed circuit board is formed by lamination, the thickness of the copper layer is limited to be less than 20 μm, and in order to ensure the electrical performance of the circuit board (for example, the impedance cannot be too large, the smaller the cross-sectional area of the trace, the greater the impedance), the trace width of the circuit board (referring to the width of the trace itself in the top view) is at least 80 μm. The copper layer of the wiring layer is formed layer by layer, and the thickness of the copper layer is not limited, so that the wiring layer can reduce the width of the wiring by increasing the thickness of the copper layer. On the other hand, the wiring layer of the invention forms the line by an additive method, which has higher process precision, so the wiring width of the wiring layer can be 30 μm.

Therefore, in the above embodiment, by forming the redistribution layer 102 on the flexible printed circuit board 101, the circuit board assembly formed by the flexible printed circuit board 101 and the redistribution layer 102 may have metal electrodes (i.e., pads) arranged densely in a small area, so that the electrodes (i.e., pads) of the circuit board assembly may be in one-to-one contact with and conducted on the chip electrodes 1033 arranged densely, thereby facilitating to increase the number of pixels of the photosensitive assembly in the filpchip process scheme, and avoiding various defects caused by the conventional wire bond process. On the other hand, the connecting band of the photosensitive assembly of the above embodiment is formed by using a flexible board, so that the connecting band can be prevented from being attached by a process requiring high-temperature hot pressing, such as an ACF, after the photosensitive chip is attached. Wherein the connection strip can electrically connect the hard board region to the connector for electrical connection with a motherboard of a terminal device (e.g., a cell phone). The soft board can be directly used as a connecting belt of the photosensitive component. It should be noted that, in the above embodiment, the flexible printed circuit board itself may not have the functional circuit of the photosensitive component, in other words, the functional circuit of the photosensitive component may be integrated into both the redistribution layer and the photosensitive chip, and at this time, the redistribution layer may separately implement the electrical function of the conventional circuit board, so the redistribution layer may also be referred to as a wiring layer or a substrate.

Based on the above analysis, in an embodiment of the present invention, the thickness of the rewiring layer trace is greater than 20 μm, so as to increase the cross-sectional area of the trace, thereby reducing the width of the rewiring layer trace without increasing the trace impedance. Because the width of the routing of the rewiring layer is reduced, the circuit board assembly formed by the soft board 101 and the rewiring layer 102 together can have metal electrodes (namely bonding pads) which are small in area and densely arranged, so that the electrodes (namely the bonding pads) of the circuit board assembly can be in one-to-one contact with and conducted with the chip electrodes 1033 densely arranged, the pixel number of the photosensitive assembly of the filmchip process scheme is increased, and various defects caused by the existing wire bond process are avoided.

FIGS. 2-14 illustrate a photosensitive assembly manufacturing flow (FIGS. 15-17 illustrate some optional steps of the photosensitive assembly manufacturing flow) according to one embodiment of the present invention, which includes the following steps.

And S100, planting copper columns on the soft plate electrodes (namely the soft plate bonding pads) of the soft plate. Note that this step should be performed before the lamination of the flexible printed circuit board cover film. After copper implantation, a covering film is pressed on the part of the flexible board, which does not correspond to the wiring layer. The copper pillar may also be a metal pillar formed of other metal materials, which will not be described in detail below. Fig. 2 shows a schematic diagram of copper pillars 1023a on the flexible board electrodes 1033 of the flexible board 101 in step S100. In one embodiment, the process of implanting the copper pillar may include the process steps of plating seed copper, disposing photoresist (dry film photoresist may be applied, or spin coating), exposing, developing, plating copper, removing photoresist, and removing seed copper. In the manufacturing process of the circuit board, a seed copper layer (such as a titanium copper seed copper layer) is sputtered on the surface of the substrate, so that the bonding force between the substrate and the metal wiring material can be improved.

And S200, filling an insulating material on the surface of the flexible printed circuit board to form a filling layer. Fig. 3 shows a schematic diagram of filling an insulating material on the surface of the flexible printed circuit board 101 to form a filling layer 1021 with a flat surface in step S200, and referring to fig. 3, in this step, the filling material may cover the copper pillar. In another embodiment, the filling material may be formed on the surface of the flexible board by molding (molding). The molding process may be compression molding or transfer molding (sometimes also referred to as injection molding).

S300, the filling layer is polished to make the surface flat and expose the copper column implanted in the step S100. Fig. 4 shows a schematic diagram of grinding the filling layer in step S300. Referring to fig. 4, in one embodiment, the surface of the filling layer 1021 may be made flush with the surface of the copper pillar 1023a implanted in step S100.

And S400, forming a seed copper layer on the surface of the ground filling layer. Fig. 5 shows a schematic view of forming a seed copper layer 1029 on the surface of the polished filling layer 1021 in step S400. Wherein, the seed copper layer is sputtered on the surface of the filling layer to improve the bonding force between the filling layer and the metal wiring material.

S500, manufacturing rewiring routing based on the seed copper layer. Fig. 6 shows a schematic diagram of fabricating rewiring layer traces 1024 based on a seed copper layer in step S500. The manner of manufacturing the rewiring trace 1024 can be realized based on processes such as film pressing (i.e., a process of attaching a photoresist dry film, which is not described in detail below), exposure, development, copper plating, and the like. And the rewiring layer routing is conducted with the metal column. The rewiring layer wiring can also form a circuit according to a preset design, and the circuit can be used as a functional circuit of the photosensitive assembly.

S600, implanting copper columns in the partial area of the routing of the rewiring layer. Fig. 7 shows a schematic diagram of copper implantation in a partial area of the rewiring layer trace in step S600. The copper column can be planted by pressing film, exposing, developing and electroplating the copper column. In one embodiment, the area in which the copper pillars are planted may be determined by alignment calibration. Referring to fig. 7, a copper pillar 1024a is formed on a partial area of the surface of the redistribution layer trace 1024.

And S700, removing the seed copper layer. Fig. 8 shows a schematic diagram of removing the seed copper layer 1029 in step S700. In one embodiment, the seed copper layer not covered by the routing layer traces may be removed by an etching process. It should be noted that the execution order of steps S700 and S600 may be interchanged. And after the seed copper layer is removed, the surface of the filling layer is exposed.

And S800, filling the insulating material on the surface of the existing filling layer again. Fig. 9 shows a schematic diagram of refilling the surface of the existing filling layer with an insulating material in step S800. In this step, after the insulating material is filled again on the surface of the existing filling layer, the filling material covers the copper posts 1024a implanted in step S600, and a new filling layer 1021 is formed.

S900, the filling layer is polished to make the surface flat and expose the copper column implanted in the step S600. Fig. 10 shows a schematic view of polishing the filling layer to make its surface flat and expose the copper pillar implanted in step S600 in step S900. In one embodiment, the surface of the filling layer 1021 may be made flush with the surface of the copper pillar 1024a implanted in step S600.

And S1000, forming a seed copper layer on the surface of the existing filling layer.

S1100, manufacturing a new rewiring layer routing based on the seed copper layer. The rewiring layer wiring can be manufactured and formed into a circuit through film pressing, exposure, development and copper plating processes.

S1200, implanting copper columns in the partial area of the routing of the rewiring layer.

And S1300, removing the seed copper layer through etching. And S1400, after the seed copper layer is removed, filling the insulating material again to enable the filling layer to cover the copper column planted in the step S1200.

S1500, the current filling layer is ground to make the surface flat and expose the copper column implanted in the step S1200.

And after the step S1500 is finished, continuously repeating the steps S1000-S1500 to form a plurality of layers of re-wiring layer routing which are mutually communicated. The rewiring layer wiring of different layers can be conducted through the copper columns. And obtaining the finished rewiring layer after the rewiring layer with the preset number of layers is manufactured for wiring. Fig. 11 shows a schematic view of forming a completed re-wiring layer.

And S1600, performing solder mask printing on the surface of the rewiring layer to form a protective layer, and simultaneously leading out a plurality of rewiring layer electrodes. Fig. 12 shows a schematic diagram of solder resist printing on the surface of the re-wiring layer in step S1600. The protective layer 1028 formed by solder resist printing is a thin film covering the copper wires (or other wires), which plays an insulating role and protects the wire layer to a certain extent. The protective layer can also play a role in preventing soldering tin from adhering so as to better avoid welding from accidentally adhering to copper wires which do not need welding. The material of the protective layer 1028 may be compatible with the filler material of the filler layer so that the two are integrated. The protective layer may be considered part of the rewiring layer.

S1700, a through hole is made in the center of the soft board and the rewiring layer. The through hole corresponds to a photosensitive area of the photosensitive chip so as to form a light through hole. Fig. 13 shows a schematic diagram of making a via 1013 in the center of the flexible board and the redistribution layer in step S1700.

And S1800, attaching a photosensitive chip on the surface of the rewiring layer. Fig. 14 shows a schematic diagram of attaching the photosensitive chip 103 on the surface of the rewiring layer in step S1800. The plurality of chip electrodes of the photosensitive chip may be in one-to-one correspondence with the plurality of rewiring layer electrodes. The chip electrode of the photosensitive chip and the rewiring layer electrode can be conducted through anisotropic conductive adhesive, ultrasonic welding, hot-press welding or reflow welding and the like. In this step, attaching the photosensitive chip to the surface of the rewiring layer may be implemented based on a Flip chip (Flip chip) process. The rewiring layer electrodes may be implemented as copper pillars (as shown in fig. 14) or gold balls. Fig. 15 shows a schematic view of a photosensitive assembly in which the rewiring layer electrodes are implemented as gold balls.

In step S1900, a steel sheet (or another metal sheet) is attached to the surface of the redistribution layer. FIG. 16 is a schematic view showing the attaching of a steel sheet to the surface of the rewiring layer in step S1900. Referring to fig. 16, the steel sheet 104 has a recess 104a, and the photo chip is accommodated in the recess 104 a. In one embodiment, the steel sheet is not in contact with the photosensitive chip and the insulating buffer layer can be filled between the steel sheet and the photosensitive chip based on an underfil process. And after the steel sheet is attached, a complete photosensitive assembly can be obtained. The steel sheet 104 is attached to the back surface of the rewiring layer 102, so that the photosensitive chip 103 can be isolated from the external environment, and the photosensitive chip 103 is prevented from being damaged due to external force impact. A reserved gap can be kept between the steel sheet 104 and the photosensitive chip 103, so that the photosensitive chip 103 is prevented from being damaged or the electric connection is prevented from being failed due to collision between the steel sheet 104 and the photosensitive chip 103. The gap may be filled with air, glue, molding, an insulating layer, etc. to better protect the chip.

In another embodiment, the steel sheet may be replaced with a molding layer in the step S1900. A molding layer may be formed on the rewiring layer and the back surface of the photosensitive chip, for example, by a molding process. Fig. 17 shows a schematic view of forming a molding layer on the rewiring layer and the back surface of the photosensitive chip in step S1900. Preferably, in order to prevent the molding material from penetrating into the photosensitive region, the rewiring layer 102 and the back surface of the photosensitive chip 103 may be filled based on an underfil process, and then the molding layer 105 may be formed based on a molding process.

In another embodiment of the present invention, after the step S1900, the surface of the molding layer 105 is further ground to thin the molding layer 105. Fig. 18 shows a schematic view of grinding the molding layer 105 to thin the molding layer.

In the above embodiments, the rewiring layer may be understood as a dummy substrate. This kind of substrate has a different manufacturing process from conventional substrates (e.g., a hard board, i.e., a PCB board, and a soft board, i.e., an FPC board). Class base plate passes through the press mold, the exposure, develop, copper facing, the packing, grinds, forms the circuit layer of one deck, because the filler material use of class base plate has higher intensity to and the heat resistance is better (be heated non-deformable), therefore class base plate has higher roughness, and every forms one deck circuit layer, will grind it (be exactly for the next layer provides the shaping plane), and switch on through the copper post between every layer, and the blind hole in the non-hardboard, the through-hole carry out the switching on of every layer. The blind holes and the through holes are formed through drilling and hole filling processes, the blind holes and the through holes are not filled enough and can be broken, and the blind holes and the through holes are filled excessively and can be short-circuited.

On the other hand, in the above embodiment, the conduction between the flexible board and the similar substrate is realized by directly forming the similar substrate on the flexible board, that is, the conduction between the flexible board and the similar substrate is realized by the copper-plated column on the flexible board, so as to replace the conduction mode of the hot-pressed conductive silver paste, thereby having higher reliability.

According to another embodiment of the present invention, there is provided another method for manufacturing a photosensitive assembly, including:

and S10, arranging metal columns on the surface of the carrier plate. In one embodiment, a seed copper layer is sputtered on the surface of the carrier plate, and then the metal posts are arranged. Preferably, the carrier is a copper substrate.

S20, filling an insulating material on the surface of the carrier plate to form a filling layer with a flat surface, and exposing the metal posts arranged in the step S10;

s30, manufacturing a rewiring layer wire on the surface of the filling layer, wherein the rewiring layer wire is conducted with the metal column;

s40, implanting metal posts in partial areas of the rewiring layer wiring;

s50, filling an insulating material on the surface of the filling layer again to enable the filling layer to cover the rewiring layer wiring and expose the metal column planted in the step S40;

repeating the steps S30-S50 until the wiring of the rewiring layer with the preset number of layers is manufactured, obtaining a complete rewiring layer, and forming a plurality of rewiring layer electrodes on the finally exposed metal columns;

s60, removing the carrier plate attached to the rewiring layer, attaching a soft board to the rewiring layer, and conducting the electrode of the soft board and the metal column of the rewiring layer; and attaching a photosensitive chip to the rewiring layer, and the rewiring layer electrodes are respectively in one-to-one contact with and conducted to the chip electrodes of the photosensitive chip (for example, the rewiring layer electrodes may be conducted by ultrasonic welding, thermocompression welding, or the like). In one embodiment, a metal pillar (which refers to a metal pillar for attaching a flexible board to the rewiring layer, and may be implemented as a copper pillar) may be further plated with a conductive material such as nickel, palladium, gold and tin, so as to improve the conductive efficiency.

Further, fig. 19 shows a schematic view of a photosensitive assembly in another embodiment of the present invention. Referring to fig. 19, according to another embodiment of the present invention, there is also provided another photosensitive assembly, and the re-wiring layer 102 of the photosensitive assembly may have a groove 102 a. The center of the recess 102a is a through hole 1013, and the through hole 1013 is a light passing hole corresponding to the light sensing area 1031. The photosensitive chip 103 is attached to the rewiring layer 102, and the photosensitive chip 103 is accommodated in the recess 102 a. In other words, the back surface of the rewiring layer 102 (or its filling layer 1021) forms a step around the via 1013, thereby forming the recess 102a, and the photosensitive chip 103 is placed on the step, and is in contact with the rewiring layer at the step (e.g., the top surface 102b of the step) and is electrically connected. In this embodiment, the photosensitive assembly further includes a steel sheet 104, and the steel sheet 104 is attached to the back surface of the rewiring layer and covers the photosensitive chip 103. The steel sheet 104 isolates the photosensitive chip 103 from the external environment, and prevents the photosensitive chip 103 from being damaged due to external impact. A reserved gap can be kept between the steel sheet 104 and the photosensitive chip 103, so that the photosensitive chip 103 is prevented from being damaged or the electric connection is prevented from being failed due to collision between the steel sheet 104 and the photosensitive chip 103. The gap may be filled with air, glue, molding, an insulating layer, etc. to better protect the chip. Note that in the present application, the steel sheet 104 may be replaced with another metal sheet.

In the above embodiment, the flexible board and the photosensitive chip are respectively located on the upper and lower sides of the redistribution layer. It should be noted, however, that the present invention is not so limited, and for example, in one alternative embodiment, the flexible board and the photosensitive chip may be located on the same side of the redistribution layer (e.g., both located on the lower side of the redistribution layer).

The above description is only a preferred embodiment of the present application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.