A fingerprint sensor chip packaging structure and manufacturing method thereof

Abstract

The present invention discloses a fingerprint sensor chip packaging structure and a manufacturing method thereof, the packaging structure comprising: a chip, the front of the chip having a photosensitive area and a chip PAD, and the chip being provided with a through hole corresponding to the position of the chip PAD; a protective film layer, which covers the front of the chip; a plastic encapsulation layer, which wraps the other five surfaces of the chip except the front, and the plastic encapsulation layer is provided with an opening communicating with the straight hole of the chip; at least one metal rewiring layer, which is arranged on the chip; wherein the bottom metal rewiring layer is arranged on the through hole wall of the chip, the through hole bottom, the opening hole wall of the plastic encapsulation layer and the surface of the plastic encapsulation layer; each metal rewiring layer is respectively covered with a passivation film layer; a signal derivation structure, which is arranged on the conduction hole of the passivation film layer. The fingerprint sensor chip packaging structure can achieve a better protection effect on the side wall of the chip, and effectively solves the problem of insufficient wiring space by externalizing the metal line.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor chip packaging, and in particular to a fingerprint sensor chip packaging structure and a manufacturing method thereof. Background Art

[0002] At present, the emergence of fingerprint sensor chips has improved the security of terminal products in terms of intelligence, such as smart phones, tablet computers, household fingerprint locks and other products. In the current common fingerprint sensor packaging process, a temporary substrate (usually glass) and the entire wafer are usually bonded together through a temporary bonding process using a solution glue with a high transmittance. After the entire packaging process is completed, the temporary substrate and the wafer are separated through a debonding process. The glue layer formed during the bonding process serves as a protective layer for the functional area of ​​the fingerprint sensor chip (in some processes, the glass substrate and the wafer will not be debonded at the end). In this packaging process, except for the chip functional area protected by the relevant film layer, the other areas of the chip (especially the four side walls of the chip) are exposed; in actual production and use, when subjected to mechanical collision, the chip can easily be damaged by the side walls and cannot be used normally, that is, the existing packaging process does not provide enough protection for the chip. Summary of the invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a fingerprint sensor chip packaging structure and a manufacturing method thereof; the fingerprint sensor chip packaging structure can achieve better protection for the chip side wall, and effectively solve the problem of insufficient wiring space by externalizing the metal line; and the manufacturing method of the packaging structure can not only reduce the packaging cost, but also effectively obtain an ultra-thin device structure, which can enhance the protection of the entire fingerprint sensor chip.

[0004] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0005] A fingerprint sensor chip packaging structure, comprising:

[0006] A chip, wherein the front side of the chip has a photosensitive area and a chip PAD, and the chip is provided with a through hole corresponding to the position of the chip PAD;

[0007] A protective film layer, which covers the front side of the chip to protect the chip PAD and photosensitive area;

[0008] A plastic encapsulation layer, which is wrapped on the other five surfaces of the chip except the front surface, and the plastic encapsulation layer is provided with an opening communicating with the through hole of the chip;

[0009] At least one metal rewiring layer is arranged on the chip; wherein the bottom metal rewiring layer is arranged on the through hole wall, the through hole bottom, the opening hole wall of the plastic sealing layer and the surface of the plastic sealing layer of the chip; each metal rewiring layer is respectively covered with a passivation film layer having a through hole;

[0010] The signal derivation structure is arranged on the via hole of the passivation film layer and is electrically connected to the metal rewiring layer.

[0011] Furthermore, the metal rewiring layer includes a metal seed layer and a metal copper layer.

[0012] Furthermore, the number of the metal redistribution layers is preferably one or two.

[0013] Furthermore, the signal derivation structure is connected to the metal redistribution layer through a pad.

[0014] Furthermore, the signal derivation structure is a solder ball.

[0015] Furthermore, the transmittance of the protective film layer is greater than 98%.

[0016] The present invention further provides a method for manufacturing a fingerprint sensor chip packaging structure, comprising the following steps:

[0017] S1, providing a substrate, and forming a protective film layer on one surface of the substrate;

[0018] S2, providing a wafer, the wafer having a front side and a back side, the front side of the wafer having a photosensitive area and a chip PAD, and forming a through hole corresponding to the position of the chip PAD on the wafer;

[0019] S3, cutting the wafer processed in step S2 into individual chips, each chip having a photosensitive area and a chip PAD, and then mounting the chip upside down on the protective film layer of the substrate obtained in step S1; after mounting, the side edge of the substrate extends outward relative to the side edge of the chip;

[0020] S4, forming a plastic sealing layer on the back side of the chip, the plastic sealing layer wraps around the other five sides of the chip except the front side, and fills the through holes of the chip;

[0021] S5, drilling a hole at a position of the plastic encapsulation layer corresponding to the through hole of the chip to obtain an opening connected to the through hole of the chip;

[0022] S6, manufacturing at least one metal rewiring layer on the chip, wherein the bottom metal rewiring layer is arranged on the through hole wall, the through hole bottom, the opening hole wall of the plastic encapsulation layer and the surface of the plastic encapsulation layer of the chip; and a passivation film layer with a through hole is respectively covered on each metal rewiring layer;

[0023] S7, forming a signal output structure at the via hole of the outermost passivation film layer;

[0024] S8, removing the substrate to obtain the fingerprint sensor chip packaging structure.

[0025] In step S2, the method for forming the through hole is: firstly, a photosensitive film layer is formed on the back side of the wafer, and then the through hole is formed at the position corresponding to the chip PAD through exposure, development and etching processes.

[0026] Among them, in step S6, first, a metal seed layer is formed on the hole wall and hole bottom of the straight through hole of the chip and the plastic sealing layer, and then a metal copper layer is formed on the metal seed layer, and then a photosensitive film layer is formed on the metal copper layer, and an opening is made on the photosensitive film layer according to the designed position, and then the metal seed layer and the metal copper layer in the opening area of ​​the photosensitive film layer are etched away by an etching process, and then the photosensitive film layer is removed to obtain the bottom metal rewiring layer, and then a passivation film layer is formed on the metal rewiring layer and the plastic sealing layer, and an opening is made at the position of the passivation film layer corresponding to the metal rewiring layer by a photolithography process or a laser opening process to obtain a via; if the metal rewiring layer is two or more layers, the metal rewiring layer and the passivation film layer covering the metal rewiring layer are continuously formed according to the above method.

[0027] Wherein, in step S7, before forming the signal derivation structure, a pad is first formed at the via hole of the passivation film layer, and then the signal derivation structure is formed on the pad.

[0028] The beneficial effects of the present invention are:

[0029] The transparent protective film layer in the chip packaging structure of the present invention protects the photosensitive area and the chip PAD of the chip, and the plastic sealing layer wraps the other five sides of the chip except the front side. Therefore, through the cooperation of the plastic sealing layer and the protective film layer, not only the chip is fully protected and the service life of the chip is improved, but also the strong photosensitivity of the packaging structure is guaranteed; in addition, the chip packaging structure leads the metal circuit to the outside through the straight hole of the chip and the metal rewiring layer, which effectively solves the problem of insufficient wiring space.

[0030] Compared with the prior art, the manufacturing method of the chip packaging structure of the present invention has the following advantages:

[0031] (1) The manufacturing method uses a plastic encapsulation molding process to wrap and protect all five surfaces of the chip except the front surface in a plastic encapsulation layer with strong mechanical properties, thereby forming a good protective effect on the side walls of the chip;

[0032] (2) For chips with high I / O density, this manufacturing method effectively solves the problem of insufficient wiring space by externalizing metal lines;

[0033] (3) The substrate used in the packaging process of this manufacturing method can be reused, which can effectively avoid waste;

[0034] (4) When the substrate used is square, the effective utilization rate of the substrate in the entire packaging process can be significantly improved, thereby reducing the packaging cost to a certain extent;

[0035] (5) This fabrication method can reduce the thickness of the sensor chip to obtain an ultra-thin device structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a structural diagram of a substrate obtained after step S1 of the manufacturing method of the present invention is completed.

[0037] Figure 2 This is a structural diagram of a wafer obtained after step S2 of the manufacturing method of the present invention is completed.

[0038] Figure 3 This is a structural diagram obtained after the step S3 of the manufacturing method of the present invention is completed.

[0039] Figure 4 This is a structural diagram obtained after the step S4 of the manufacturing method of the present invention is completed.

[0040] Figure 5 This is a structural diagram obtained after the step S5 of the manufacturing method of the present invention is completed.

[0041] Figure 6 This is a structural diagram obtained after the step S6 of the manufacturing method of the present invention is completed.

[0042] Figure 7 This is a structural diagram obtained after the step S7 of the manufacturing method of the present invention is completed.

[0043] Figure 8 This is a structural diagram of the fingerprint sensor chip packaging structure obtained after the step S8 of the manufacturing method of the present invention is completed. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0045] like Figure 8 A preferred embodiment of a fingerprint sensor chip packaging structure is shown, the packaging structure comprises:

[0046] A chip 12, wherein the front side of the chip 12 has a photosensitive area 122 and a chip PAD (pin) 121, and the chip 12 is provided with a through hole corresponding to the position of the chip PAD 121;

[0047] A protective film layer 11, which covers the front surface of the chip 12, and protects the chip PAD 122 and the photosensitive area 121; the protective film layer 11 is a transparent film layer, and its light transmittance is greater than 98%;

[0048] A plastic encapsulation layer 13, which is wrapped around the other five surfaces of the chip 12 except the front surface, and the plastic encapsulation layer 13 is provided with an opening communicating with the through hole of the chip 12;

[0049] A metal rewiring layer 14 is disposed on the chip 12; the metal rewiring layer 14 includes a metal seed layer and a metal copper layer covering the metal seed layer; in the present embodiment, the metal rewiring layer 14 is a layer, and the metal rewiring layer covers the through hole wall of the chip 12, the through hole bottom, the opening hole wall of the plastic encapsulation layer 13, and the surface of the plastic encapsulation layer 13; the metal rewiring layer 14 is covered with a passivation film layer 15 having a through hole;

[0050] The signal lead-out structure 16 is disposed on the conduction hole of the passivation film layer 15 and is electrically connected to the metal rewiring layer 14. In this embodiment, the signal lead-out structure 16 is connected to the metal rewiring layer 14 through a pad 17 disposed in the conduction hole of the passivation film layer 15; the signal lead-out structure 16 can be a solder ball or other structure, and in this embodiment, the signal lead-out structure 16 is selected to be a solder ball.

[0051] The method for manufacturing the fingerprint sensor chip packaging structure of this embodiment includes the following steps:

[0052] S1, providing a substrate 10, and forming a protective film layer 11 on one surface of the substrate 10 by glue coating or glue spraying process, so as to obtain Figure 1 The structure shown; the material of the substrate 10 can be glass, metal, ceramic, etc., and the substrate 10 can be round or square; in this embodiment, the substrate 10 is made of glass and has a square structure;

[0053] S2, providing a wafer 12a, the wafer 12a having a front side and a back side, the front side of the wafer 12a having a photosensitive area 122 and a chip PAD 121; firstly, the back side of the wafer 12a is thinned by a grinding and thinning process, a front protective film is attached to the front side of the wafer 12a, and then a photosensitive film layer is formed on the back side of the wafer by a coating process or a lamination process, an opening is formed on the photosensitive film layer at a position corresponding to the chip PAD 121 by processes such as exposure and development, and then a through hole 123 is formed on the wafer 12a by an etching process, and then the photosensitive film layer on the back side of the wafer and the front protective film on the front side of the wafer are removed by a degumming process, and the following is obtained: Figure 2 The structure shown;

[0054] S3, cutting the wafer processed in step S2 into individual chips, each chip 12 having a photosensitive region 122 and a chip PAD 121, and then mounting the chip 12 upside down on the protective film layer 11 on the substrate 10 obtained in step S1; after mounting, the side edge of the substrate 10 extends outward relative to the side edge of the chip 12; the structure obtained in step S3 is as shown Figure 3 As shown;

[0055] S4, forming a plastic sealing layer 13 on the back side of the chip 12 by injection molding process, and obtaining Figure 4 The structure shown; the plastic encapsulation layer 13 is wrapped around the other five surfaces of the chip 12 except the front surface, and is filled in the through hole 123 of the chip 12;

[0056] S5, a hole is opened at the position of the through hole of the chip in the plastic packaging layer 13 by a laser opening process, so as to obtain an opening 131 connected with the through hole 123 of the chip 12, as shown in FIG. Figure 5 As shown;

[0057] S6, forming a metal rewiring layer 14 on the chip 12, the metal rewiring layer 14 covers the through hole wall, the through hole bottom, the opening hole wall of the plastic encapsulation layer 13 and the surface of the plastic encapsulation layer of the chip 12; and covering the metal rewiring layer 14 with a passivation film layer 15 having a through hole;

[0058] Specifically, in the present embodiment, a metal seed layer is first formed on the hole wall and the bottom of the through hole 123 of the chip 12 and the plastic sealing layer 13 by a PVD process; the metal seed layer is a Ti / Cu layer, and in the present embodiment, the metal seed layer is selected to be a Ti layer; then a metal copper layer is formed on the metal seed layer by an electroplating process, and then a photosensitive film layer is formed on the metal copper layer by a photolithography process, and an opening is made on the photosensitive film layer according to the designed position, and then the metal seed layer and the metal copper layer in the opening area of ​​the photosensitive film layer are etched away by an etching process, and then the photosensitive film layer is removed by a degumming process to obtain a metal rewiring layer 14, and then a passivation film layer 15 is formed on the metal rewiring layer 14 and the plastic sealing layer 13 by a glue coating process, a glue printing process or a dry film pressing process, and an opening is made at the position of the passivation film layer 15 corresponding to the metal rewiring layer 14 to obtain a via, thereby obtaining the following Figure 6 The structure shown; the passivation film layer can be a photosensitive film layer or a non-photosensitive film layer. In the present embodiment, the passivation film layer is preferably a photosensitive film layer; when the passivation film layer is a photosensitive film layer, the via hole on the passivation film layer is formed by a photolithography process; if the passivation film layer is a non-photosensitive film layer, the via hole on the passivation film layer can be formed by a laser opening process;

[0059] S7, forming a signal output structure 16 at the via hole of the passivation film layer 15, such as Figure 7 As shown; in this embodiment, before forming the signal lead-out structure 16, a pad 17 can be first formed at the conductive hole of the passivation film layer 15, and then the signal lead-out structure 16 can be formed on the pad 17; the signal lead-out structure 16 can be a solder ball or other structure; in this embodiment, the signal lead-out structure 16 is selected to be a solder ball.

[0060] S8, separating the substrate 10 and the chip 12 through a debonding process to obtain Figure 8 The fingerprint sensor chip packaging structure shown.

[0061] The protective film layer 11 in the chip packaging structure of this embodiment protects the photosensitive area 122 of the chip 12 and the chip PAD121, and the plastic layer 13 wraps the other five surfaces of the chip 12 except the front surface, so that the present invention can achieve comprehensive protection of the chip 12 through the cooperation of the plastic layer 13 and the protective film layer 11, thereby improving the service life of the chip 12; in addition, the chip packaging structure leads the metal line to the outside through the through hole of the chip 12 and the metal rewiring layer 14, effectively solving the problem of insufficient wiring space. And the manufacturing method of the packaging structure can not only reduce the packaging cost, but also effectively obtain an ultra-thin device structure, which can enhance the protection of the entire fingerprint sensor chip.

[0062] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a fingerprint sensor chip packaging structure, the fingerprint sensor chip packaging structure comprising: A chip, wherein the front of the chip has a photosensitive area and a chip PAD, and the chip is provided with a through hole corresponding to the position of the chip PAD; a protective film layer, which covers the front of the chip to protect the chip PAD and the photosensitive area; a plastic encapsulation layer, which is wrapped on the other five surfaces of the chip except the front, and the plastic encapsulation layer is provided with an opening connected to the through hole of the chip; at least one metal rewiring layer, which is arranged on the chip; wherein the bottom metal rewiring layer is arranged on the through hole wall of the chip, the through hole bottom, the opening hole wall of the plastic encapsulation layer and the surface of the plastic encapsulation layer; each metal rewiring layer is respectively covered with a passivation film layer with a via hole; a signal derivation structure, which is arranged on the via hole of the passivation film layer and is electrically connected to the metal rewiring layer; characterized in that the manufacturing method comprises the following steps: S1, providing a substrate, and forming a protective film layer on one surface of the substrate; S2, providing a wafer, the wafer having a front side and a back side, the front side of the wafer having a photosensitive area and a chip PAD, and forming a through hole corresponding to the position of the chip PAD on the wafer; S3, cutting the wafer processed in step S2 into individual chips, each chip having a photosensitive area and a chip PAD, and then mounting the chip upside down on the protective film layer on the substrate obtained in step S1; after mounting, the side edge of the substrate extends outward relative to the side edge of the chip; S4, forming a plastic sealing layer on the back side of the chip, the plastic sealing layer wraps around the other five sides of the chip except the front side, and fills the through holes of the chip; S5, drilling a hole at a position of the plastic encapsulation layer corresponding to the through hole of the chip to obtain an opening connected to the through hole of the chip; S6, manufacturing at least one metal rewiring layer on the chip, wherein the bottom metal rewiring layer is arranged on the through hole wall, the through hole bottom, the opening hole wall of the plastic encapsulation layer and the surface of the plastic encapsulation layer of the chip; and a passivation film layer with a through hole is respectively covered on each metal rewiring layer; S7, forming a signal output structure at the via hole of the outermost passivation film layer; S8, removing the substrate to obtain the fingerprint sensor chip packaging structure.

2. The method for manufacturing a fingerprint sensor chip packaging structure according to claim 1, characterized in that: The metal rewiring layer includes a metal seed layer and a metal copper layer.

3. The method for manufacturing a fingerprint sensor chip packaging structure according to claim 1, characterized in that: The number of the metal rewiring layer is one or two.

4. The method for manufacturing a fingerprint sensor chip packaging structure according to claim 1, characterized in that: The signal output structure is connected to the metal rewiring layer through a pad.

5. The method for manufacturing a fingerprint sensor chip packaging structure according to claim 1, characterized in that: The signal derivation structure is a solder ball.

6. The method for manufacturing a fingerprint sensor chip packaging structure according to claim 1, characterized in that: The transmittance of the protective film layer is greater than 98%.

7. The method for manufacturing a fingerprint sensor chip packaging structure according to claim 1, characterized in that: In step S2, the method for forming the through hole is: firstly, a photosensitive film layer is formed on the back side of the wafer, and then the through hole is formed at the position corresponding to the chip PAD through exposure, development and etching processes.

8. The method for manufacturing a fingerprint sensor chip packaging structure according to claim 1, characterized in that: In step S6, first, a metal seed layer is formed on the hole wall and bottom of the through hole of the chip and on the plastic sealing layer, and then a metal copper layer is formed on the metal seed layer, and then a photosensitive film layer is formed on the metal copper layer, and an opening is made on the photosensitive film layer according to the designed position, and then the metal seed layer and the metal copper layer in the opening area of ​​the photosensitive film layer are etched away by an etching process, and then the photosensitive film layer is removed to obtain the bottom metal rewiring layer, and then a passivation film layer is formed on the metal rewiring layer and the plastic sealing layer, and an opening is made at the position of the passivation film layer corresponding to the metal rewiring layer by a photolithography process or a laser opening process to obtain a via; if the metal rewiring layer is two or more layers, the metal rewiring layer and the passivation film layer covering the metal rewiring layer are continuously formed according to the above method.

9. The method for manufacturing a fingerprint sensor chip packaging structure according to claim 1, characterized in that: In step S7, before forming the signal derivation structure, a pad is first formed at the via hole of the passivation film layer, and then the signal derivation structure is formed on the pad.

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