CN109192708B - Packaging structure and packaging method of fingerprint chip - Google Patents
Packaging structure and packaging method of fingerprint chip Download PDFInfo
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- CN109192708B CN109192708B CN201811069199.8A CN201811069199A CN109192708B CN 109192708 B CN109192708 B CN 109192708B CN 201811069199 A CN201811069199 A CN 201811069199A CN 109192708 B CN109192708 B CN 109192708B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
- H01L23/31—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape
- H01L23/3107—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape the device being completely enclosed
- H01L23/315—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape the device being completely enclosed the encapsulation having a cavity
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
- G06V40/12—Fingerprints or palmprints
- G06V40/13—Sensors therefor
- G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
- H01L21/56—Encapsulations, e.g. encapsulation layers, coatings
- H01L21/561—Batch processing
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
- H01L21/56—Encapsulations, e.g. encapsulation layers, coatings
- H01L21/568—Temporary substrate used as encapsulation process aid
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
- H01L24/93—Batch processes
- H01L24/94—Batch processes at wafer-level, i.e. with connecting carried out on a wafer comprising a plurality of undiced individual devices
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/10—Bump connectors; Manufacturing methods related thereto
- H01L2224/11—Manufacturing methods
Abstract
The invention discloses a packaging structure and a packaging method of a fingerprint chip.A cavity is arranged on the second surface of the fingerprint chip, when a user carries out fingerprint identification, the cavity can enable the fingerprint chip to generate larger deformation under the same touch pressure, the sensitivity can be greatly improved, a sealing cover for sealing the cavity can be used as a substrate and used for forming a metal interconnection layer electrically connected with a welding pad of the fingerprint chip, the metal interconnection layer is used for being connected with an external circuit, and compared with the mode of directly interconnecting the welding pad on the first surface with the external circuit, enough space is arranged on the surface of the sealing cover for distributing the metal interconnection layer, so that the fingerprint chip is convenient to be interconnected with the external circuit.
Description
Technical Field
The invention relates to the technical field of chip packaging, in particular to a packaging structure and a packaging method of a fingerprint chip.
Background
With the development of science and technology, more and more electronic devices are widely applied to daily life and work of people, bring great convenience to daily life and work of people, and become an indispensable important tool for people at present. At present, electronic equipment has increasingly powerful functions, more and more stored information is increasingly important, and in order to ensure the safety of user information, the electronic equipment needs to have an identity recognition function.
The mode of carrying out identification through the fingerprint is the main mode of carrying out identification by the electronic equipment at present because of having the advantages of simple operation, good accuracy and high safety. The electronic equipment realizes the fingerprint identification function by internally integrating the fingerprint chip. The existing fingerprint chip is inconvenient to be connected with an external circuit, and the sensitivity is lower when fingerprint identification is carried out.
Disclosure of Invention
In order to solve the above problems, the technical solution of the present invention provides a fingerprint chip package structure and a fingerprint chip package method, which are convenient for connection with an external circuit and have high sensitivity.
In order to achieve the above purpose, the invention provides the following technical scheme:
a package structure of a fingerprint chip, the package structure comprising:
a fingerprint chip comprising opposing first and second surfaces; the first surface is provided with a functional area and a peripheral area surrounding the functional area, the functional area is provided with a detection unit for detecting fingerprint information, and the peripheral area is provided with a welding pad electrically connected with the detection unit; the second surface comprises a first area arranged opposite to the functional area and a second area surrounding the first area; the first area is provided with a cavity; the second area is provided with an opening used for exposing the welding pad;
a cover secured to the second surface, the cover sealing the cavity; the cover exposes the opening;
the set is in interconnect metal level in the opening, interconnect metal level with the welding pad is connected, and extends to the closing cap deviates from a side surface of fingerprint chip, interconnect metal level is used for being connected with external circuit.
Preferably, in the above package structure, a welding protrusion is disposed on a side of the cover facing away from the fingerprint chip, the welding protrusion is electrically connected to the interconnection metal layer, and the interconnection metal layer is electrically connected to the external circuit through the welding protrusion.
Preferably, in the above package structure, the bonding bump includes a solder ball or a metal pad.
Preferably, in the above package structure, the second surface and the cover are fixed by an adhesive layer.
Preferably, in the above package structure, the cover is a semiconductor board or a glass board.
Preferably, in the above package structure, an edge of the cover is aligned with an edge of the opening.
Preferably, in the above package structure, in a direction perpendicular to the cover, an orthogonal projection of the functional region on the cover is located completely within an orthogonal projection of the cavity on the cover.
Preferably, in the above package structure, the opening includes:
the groove is arranged in the second area and corresponds to the welding pad area, and the depth of the groove is smaller than the thickness of the fingerprint chip;
and a through hole located at the bottom of the groove.
Preferably, in the above package structure, the opening is a one-step formed groove, and a width of the groove is constant in a direction from the first surface to the second surface.
Preferably, in the package structure, the opening is a one-step formed groove, and a width of the groove gradually increases in a direction from the first surface to the second surface.
Preferably, in the above package structure, an insulating layer is provided between the interconnection metal layer and the sidewall of the opening;
and the surface of the interconnection metal layer is covered with a solder mask layer.
The invention also provides a packaging method of the fingerprint chip, which comprises the following steps:
providing a wafer, wherein the wafer comprises a plurality of fingerprint chips; a cutting channel is arranged between every two adjacent fingerprint chips; the fingerprint chip comprises a first surface and a second surface which are opposite; the first surface is provided with a functional area and a peripheral area surrounding the functional area, the functional area is provided with a detection unit for detecting fingerprint information, and the peripheral area is provided with a welding pad electrically connected with the detection unit; the second surface comprises a first area arranged opposite to the functional area and a second area surrounding the first area;
forming a cavity in the first region;
fixing a sealing cover on the surface of the wafer, wherein the sealing cover covers the second surfaces of all the fingerprint chips;
carrying out graphical processing on the sealing cover and the wafer to expose the welding pad;
forming an interconnection metal layer in the opening, wherein the interconnection metal layer is connected with the welding pad and extends to the surface of one side of the sealing cover, which is far away from the fingerprint chip, and the interconnection metal layer is used for being connected with an external circuit;
and cutting based on the cutting channel to form a plurality of single-grain fingerprint chip packaging structures.
Preferably, in the above packaging method, the forming a cavity in the first region includes:
fixing a temporary carrier plate on the front surface of the wafer; the temporary carrier plate covers all the first surfaces of the fingerprint chips;
inverting the wafer, and horizontally placing the temporary carrier plate below the wafer;
the cavity is formed in the first region.
Preferably, in the above packaging method, the wafer and the temporary carrier are temporarily bonded and fixed by a hot melt adhesive or an optical adhesive.
Preferably, in the above packaging method, the method further includes:
removing the temporary carrier plate before cutting treatment;
or, after the cutting treatment is finished, the temporary carrier plate is removed.
Preferably, in the above packaging method, the method for etching the cap and the wafer includes:
removing the part of the sealing cover corresponding to the second area to expose the second area;
and etching the wafer, and forming an opening exposing the welding pad in the second area of each chip.
Preferably, in the above encapsulation method, the method of forming the opening includes:
performing half-cutting treatment on the wafer, and forming a groove in the second area corresponding to the welding pad area;
and etching the wafer, and forming a through hole at the bottom of the groove, wherein the through hole exposes the welding pad.
Preferably, in the above encapsulation method, the method of forming the opening includes:
carrying out deep cutting treatment on the wafer, forming a groove in the second area corresponding to the welding pad area, wherein the bottom of the groove and the welding pad are provided with thin layers with the thickness smaller than the preset thickness, and etching the thin layers through an etching process to expose the welding pad; wherein the width of the groove is constant or gradually increased in a direction from the first surface to the second surface.
Preferably, in the above packaging method, the removing of the portion of the cover corresponding to the second region includes:
removing the part, corresponding to the second area, of the sealing cover through a cutting process to expose the adhesive layer between the fingerprint chip and the sealing cover, and removing the adhesive layer through a plasma process to expose the fingerprint chip;
or removing the part of the sealing cover corresponding to the second area through an etching process to expose the adhesive layer between the fingerprint chip and the sealing cover, and removing the adhesive layer through a plasma process to expose the chip.
Preferably, in the above packaging method, the forming of the interconnection metal layer in the opening includes:
forming an insulating layer in the opening, wherein the insulating layer covers the side wall of the opening and exposes the welding pad;
and forming the interconnection metal layer on the surface of the insulating layer, wherein the interconnection metal layer is electrically connected with the welding pad at the bottom of the opening and extends to the surface of the sealing cover.
As can be seen from the above description, in the fingerprint chip packaging structure and the fingerprint chip packaging method provided in the technical solution of the present invention, the cavity is disposed on the second surface of the fingerprint chip, and when a user performs fingerprint identification, the cavity can enable the fingerprint chip to deform greatly under the same touch pressure, so that the sensitivity can be greatly improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a fingerprint chip according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a package structure of a fingerprint chip according to an embodiment of the present invention;
fig. 3 is a schematic diagram of another package structure of a fingerprint chip according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a package structure of a fingerprint chip according to another embodiment of the present invention;
fig. 5-14 are schematic flow charts of a fingerprint chip packaging method according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
When the traditional fingerprint chip senses that a finger touches to generate a detection signal, the intensity of the detection signal is low, so that the sensitivity of the fingerprint chip is low.
In order to solve the above problem, as shown in fig. 1, fig. 1 is a schematic structural diagram of a fingerprint chip according to an embodiment of the present invention, and in the manner shown in fig. 1, a fingerprint chip 11 has opposite front and back surfaces, and the front surface thereof has a detecting unit 12 and a pad 13 electrically connected to the detecting unit 12. The back side thereof has a cavity 14, and the amount of deformation is increased by the cavity 14 to improve the sensitivity. The fingerprint chip 11 electrically connects the pad 13 with the outside through a wire.
Compared with the conventional method of attaching and fixing the fingerprint chip and the substrate with the cavity structure, the method shown in fig. 1 directly forms the cavity 14 on the back surface of the fingerprint chip 11, which reduces the thickness of the package structure, but requires a wire to connect the pad 13 on the front surface thereof to an external electrical connection. With the increased resolution of the fingerprint chip and the miniaturized design requirements of the chip, the number of the front pads 13 is large, the size is small, the density is large, and the connection with an external circuit is still inconvenient.
In order to solve the above problems, embodiments of the present invention provide a package structure and a package method for a fingerprint chip, where a cavity is disposed on a second surface of the fingerprint chip, and when a user performs fingerprint identification, the cavity may deform the fingerprint chip greatly under the same touch pressure, so that the fingerprint chip obtains a detection signal with a higher strength, thereby improving sensitivity.
The second surface of the fingerprint chip is fixed with a sealing cover for sealing the cavity, the sealing cover can be used as a substrate for forming a metal interconnection layer electrically connected with a welding pad of the fingerprint chip, the metal interconnection layer is used for being connected with an external circuit, and compared with a mode of directly interconnecting a first surface and the external circuit, the surface of the sealing cover is provided with enough space for distributing the metal interconnection layer, so that the metal interconnection layer is convenient to be interconnected with the external circuit.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Referring to fig. 2, fig. 2 is a schematic diagram of a package structure of a fingerprint chip according to an embodiment of the present invention, where the package structure includes: the fingerprint chip 21 comprises a first surface and a second surface which are opposite; and a cover 22 secured to the second surface.
The first surface is provided with a functional area and a peripheral area surrounding the functional area, the functional area is provided with a detection unit 211 for detecting fingerprint information, and the peripheral area is provided with a welding pad 212 electrically connected with the detection unit 211; the second surface comprises a first area arranged opposite to the functional area and a second area surrounding the first area; the first region is provided with a cavity 213; the second region is provided with an opening 214 for exposing the pad. The cover seal 22 seals the cavity 213; the cover 22 exposes the opening 214.
The packaging structure further comprises an interconnection metal layer 31 arranged in the opening 214, the interconnection metal layer 31 is connected with the pad 212 and extends to one side surface of the cover 22 departing from the fingerprint chip 21, and the interconnection metal layer 31 is used for being connected with an external circuit.
In the embodiment of the present invention, the fingerprint chip 21 may be a capacitive fingerprint chip, and the detection unit 211 collects fingerprint information based on a capacitance detected when a finger touches the fingerprint chip. In this mode, the cavity 213 is provided, and a finger touch causes a larger amount of deformation, so that the detected capacitance signal strength is larger, and the sensitivity is improved.
Or an ultrasonic fingerprint chip. The detection unit 211 may emit an ultrasonic wave and detect the reflected ultrasonic wave, and the detection unit 211 collects fingerprint information based on the ultrasonic wave detected when the finger touches. In this mode, the cavity 213 is provided, and a larger amount of deformation is caused by a finger touch, so that the intensity of the emitted ultrasonic wave and the reflected ultrasonic wave is increased, the intensity of the detected ultrasonic signal is increased, and the sensitivity is improved. In this way, the detection unit 211 is made of a piezoelectric material, and can emit ultrasonic waves and collect reflected ultrasonic waves when being deformed by pressure.
The packaging structure directly forms the cavity 213 on the second surface of the fingerprint chip 21, and the cavity 213 can be formed in the wafer-level packaging process of preparing the fingerprint chip 21, so that the manufacturing process is simple and the thickness of the packaging structure is not increased compared with a mode of independently preparing cavities by adopting other substrates.
As shown in fig. 2, a welding bump 32 is disposed on a side of the cover 22 away from the fingerprint chip 21, the welding bump 32 is electrically connected to the interconnection metal layer 31, and the interconnection metal layer 31 is electrically connected to the external circuit through the welding bump 32. The bonding bumps 32 include solder balls or metal pads, and the bonding bumps 32 include, but are not limited to, solder balls and metal pads. The bonding bumps 32 may be electrically connected to an external circuit by means of soldering.
The edge of the cover 22 is aligned with the edge of the opening 214. That is, the cap 22 does not block the opening 214, so that the interconnection metal layer 31 is formed.
An insulating layer 33 is arranged between the interconnection metal layer 31 and the side wall of the opening 214; the surface of the interconnection metal layer 31 is covered with a solder mask layer 34. The surface of the solder mask layer 34 is provided with a through hole exposing the metal interconnection layer 31, and the through hole is used for arranging the welding bump 31.
Optionally, the second surface and the cover 22 are fixed by a glue layer. The cover 22 is a semiconductor board or a glass board.
In a direction perpendicular to the cover 22, the orthographic projection of the functional region on the cover 22 is entirely located within the orthographic projection of the cavity 213 on the cover 22. Thus, in this direction, the cavity 213 completely covers the detection unit 211, so that when a finger touches, the area directly opposite to the detection unit 211 has a larger deformation amount, and the fingerprint detection accuracy is improved.
In the manner shown in fig. 2, the opening 214 includes: a groove 214a disposed in the second region corresponding to the pad 212, wherein the depth of the groove 214a is smaller than the thickness of the fingerprint chip 21; and a through hole 214b at the bottom of the groove 214 a. In this way, when the opening 214 is formed on the second surface of the fingerprint chip 21, two times of etching are required, the groove 214a is formed by the first etching, and then the through hole 214b is formed on the basis of the groove 214a by the second etching.
Referring to fig. 3, fig. 3 is a schematic view of another package structure of a fingerprint chip according to an embodiment of the present invention, and the manner shown in fig. 3 is different from that shown in fig. 2 in that the opening 214 is a one-step formed groove, and the width of the groove gradually increases in a direction from the first surface to the second surface. In the manner shown in fig. 3, the cover 22 and the fingerprint chip 21 can be cut at one time by directly adopting a deep cutting process to expose the bonding pads 212.
The structure of the opening 214 includes, but is not limited to, the manner shown in fig. 2 and fig. 3, and the specific structure of the opening 214 may be designed according to requirements, for example, in other manners, the package structure may also be as shown in fig. 4, fig. 4 is a schematic diagram of a package structure of another fingerprint chip provided by an embodiment of the present invention, and the manner shown in fig. 4 is different from the manner shown in fig. 2 in that the opening 214 is a one-step formed groove, and a width of the groove is constant in a direction from the first surface to the second surface, in which the opening is a vertical through hole, and the second surface extends to the pad 212.
As can be seen from the above description, in the package structure provided in the embodiment of the present invention, the cavity 213 disposed on the second surface of the chip can improve the sensitivity, and the interconnection metal layer 31 disposed on the surface of the cap 22 and connected to the pad 212 can extend the metal interconnection layer for connecting to an external circuit to the back surface of the cap 22 with a larger area, so as to facilitate the connection to the external circuit without affecting the functional area of the first surface.
Based on the foregoing package structure embodiment, another embodiment of the present invention further provides a packaging method, where the packaging method is shown in fig. 5 to 14, and fig. 5 to 14 are schematic flow diagrams of a fingerprint chip packaging method provided in an embodiment of the present invention, where the packaging method includes:
step S11: as shown in fig. 5 and 6, a wafer 100 is provided.
Fig. 5 is a top view of the front surface of the wafer 100, and fig. 6 is a cross-sectional view of fig. 5 at P-P'.
The wafer 100 includes a plurality of fingerprint chips 21; a cutting channel 200 is arranged between the adjacent fingerprint chips 21; the fingerprint chip 21 comprises a first surface and a second surface which are opposite; the first surface is provided with a functional area and a peripheral area surrounding the functional area, the functional area is provided with a detection unit 211 for detecting fingerprint information, and the peripheral area is provided with a welding pad 212 electrically connected with the detection unit 211; the second surface includes a first region disposed opposite the functional region and a second region surrounding the first region.
Step S12: as shown in fig. 7 and 8, a cavity 213 is formed in the first region.
In this step, the forming of the cavity 213 in the first region includes: firstly, fixing a temporary carrier plate 23 on the front surface of the wafer; the temporary carrier plate 23 covers all the first surfaces of the fingerprint chips 21; then, as shown in fig. 7, the wafer 100 is inverted, and the temporary carrier plate 23 is horizontally placed and located below the wafer 100; finally, as shown in fig. 8, the cavity 213 is formed in the first region, and the cavity 213 may be formed through an etching process. The temporary carrier plate 23 may be a glass plate.
Optionally, the wafer 100 and the temporary carrier 23 are temporarily bonded and fixed by a hot melt adhesive or an optical adhesive, so that the temporary carrier 23 is directly separated by heating or lighting.
Step S13: as shown in fig. 9, a cover 22 is fixed on the surface of the wafer 100, and the cover 22 covers all the second surfaces of the fingerprint chips 21.
Step S14: as shown in fig. 10-12, the cap 22 and the wafer 100 are patterned to expose the bonding pads 212.
In this step, the method for performing the patterning process on the cap 22 and the wafer 100 includes: first, as shown in fig. 10, a portion of the cover 22 corresponding to the second region is removed to expose the second region. Then, as shown in fig. 11 and 12, the wafer 100 is etched, and an opening exposing the pad is formed in the second region of each chip.
In this step, the removing of the portion of the cover 22 corresponding to the second region includes: removing the part of the sealing cover 22 corresponding to the second area through a cutting process to expose the adhesive layer between the fingerprint chip 21 and the sealing cover 22, and removing the adhesive layer through a plasma process to expose the fingerprint chip 21; or, the part of the sealing cover 22 corresponding to the second area is removed through an etching process to expose the adhesive layer between the fingerprint chip 21 and the sealing cover 22, and the adhesive layer is removed through a plasma process to expose the fingerprint chip 21.
In this embodiment, the method for forming the opening 214 includes: firstly, as shown in fig. 11, a half-cut process is performed on the wafer 100, a groove 214a is formed in the second region corresponding to the pad 212, and the depth of the groove 214a is smaller than the thickness of the fingerprint chip 21; the cutting depth of the half-cutting process is not less than half of the thickness of the fingerprint chip 21, and the distance between the bottom of the groove 214a and the pad 212 is not less than 20 microns. Then, as shown in fig. 12, the wafer 100 is etched, a through hole 214b is formed at the bottom of the groove 214a, and the through hole 214b exposes the pad 212, thereby forming an opening 214. The through hole 214b may be formed by dry etching, wet etching or laser etching.
According to the mode, firstly, a cutting process is carried out, a part of the fingerprint chip 21 is removed, a groove 214a with a larger size is formed, then, a through hole 214b is formed through an etching process, the etching with a larger depth is not needed, and the side wall of the formed opening 214 can be ensured to have a better appearance.
The packaging method is used for manufacturing the package structure shown in fig. 2, and the forming process step of the opening 214 may be prepared by selecting a corresponding process method according to the shape of the opening 214 and the material of the cover 22, including but not limited to the manner shown in fig. 10-12.
As another mode, according to the shape of the opening 214, the method for forming the opening 214 includes: performing deep cutting processing on the wafer 100, forming a groove in the second area corresponding to the welding pad 212 area, wherein the bottom of the groove and the welding pad are provided with thin layers with thicknesses smaller than a preset thickness, and etching the thin layers through an etching process to expose the welding pad; the thickness of the thin layer does not exceed 20 microns. Wherein the width of the groove is constant in the direction from the first surface to the second surface, as shown in fig. 4, or the width of the groove gradually increases, as shown in fig. 3. If the portion of the cover 22 corresponding to the second region is cut by a cutting process, and the fingerprint chip 21 is cut by the cutting process to form the opening 214, the cutting of the wafer 100 and the cutting of the cover 22 may be performed by a one-time cutting or two cutting steps.
The fingerprint chip 21 is cut through a cutting process in the half-cut processing and the deep-cut processing, the cutting depths of the half-cut processing and the deep-cut processing are different, the cutting depth of the half-cut processing is smaller than that of the deep-cut processing, a larger distance is reserved between the bottom of the formed groove and the welding pad 212 after the half-cut processing, a through hole needs to be etched to a larger depth to form and expose the welding pad 212, and the bottom of the formed groove and the welding pad 212 only have a thin layer after the deep-cut processing.
Step S15: as shown in fig. 12, an interconnection metal layer 31 is formed in the opening 214, the interconnection metal layer 31 is connected to the pad 212 and extends to a side surface of the cover 22 facing away from the fingerprint chip 21, and the interconnection metal layer 31 is used for connecting with an external circuit.
In this step, the insulating layer 33 is first formed on the sidewall of the opening 214, and the insulating layer 33 extends to the surface of the cap 22. The insulating layer 33 exposes the pad 212 at the bottom of the opening 214. Then, an interconnection metal layer 31 is formed on the surface of the insulating layer 33, the interconnection metal layer 31 is electrically connected to the pad 212 at the bottom of the opening 214, and the interconnection metal layer 31 extends to the surface of the cap 22. Then, a solder resist layer 34 is formed on the surface of the interconnection metal layer 31, and the solder resist layer 34 extends to the surface of the cap 22. The area of the solder resist layer 34 extending to the surface of the cover 22 is provided with a through hole for exposing the underlying interconnection metal layer 31, the through hole being used for providing a solder bump 32
Step S16: as shown in fig. 13, a plurality of package structures of the single fingerprint chips 21 are formed by performing the cutting process based on the cutting channel 200.
The packaging method further comprises the following steps: before the cutting treatment, removing the temporary carrier plate 23; or, after the cutting process is completed, the temporary carrier 23 is removed. The temporary carrier plate 23 is removed after the formation of the interconnection metal layer 31, and in particular, the temporary carrier plate 23 is removed after the formation of the solder bumps 32.
The packaging method provided by the embodiment of the invention is used for preparing the packaging structure provided by the embodiment of the invention, the manufacturing process is simple, the manufacturing cost is low, and the formed packaging structure has high sensitivity and is convenient to be connected with an external circuit.
It should be noted that, in the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in an article or device that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (20)
1. A packaging structure of a fingerprint chip is characterized in that the packaging structure comprises:
a fingerprint chip comprising opposing first and second surfaces; the first surface is provided with a functional area and a peripheral area surrounding the functional area, the functional area is provided with a detection unit for detecting fingerprint information, and the peripheral area is provided with a welding pad electrically connected with the detection unit; the second surface comprises a first area arranged opposite to the functional area and a second area surrounding the first area; the first area is provided with a cavity; the second area is provided with an opening used for exposing the welding pad;
a cover secured to the second surface, the cover sealing the cavity; the cover exposes the opening;
the set is in interconnect metal level in the opening, interconnect metal level with the welding pad is connected, and extends to the closing cap deviates from a side surface of fingerprint chip, interconnect metal level is used for being connected with external circuit.
2. The package structure according to claim 1, wherein a side of the cover facing away from the fingerprint chip is provided with a solder bump, the solder bump is electrically connected to the interconnection metal layer, and the interconnection metal layer is electrically connected to the external circuit through the solder bump.
3. The package structure of claim 2, wherein the bonding bump comprises a solder ball or a metal pad.
4. The package structure of claim 1, wherein the second surface and the cover are fixed by a glue layer.
5. The package structure of claim 1, wherein the lid is a semiconductor board or a glass board.
6. The package structure of claim 1, wherein an edge of the cover is aligned with an edge of the opening.
7. The package structure according to claim 1, wherein an orthographic projection of the functional region on the cover in a direction perpendicular to the cover is entirely within an orthographic projection of the cavity on the cover.
8. The package structure of claim 1, wherein the opening comprises:
the groove is arranged in the second area and corresponds to the welding pad area, and the depth of the groove is smaller than the thickness of the fingerprint chip;
and a through hole located at the bottom of the groove.
9. The package structure of claim 1, wherein the opening is a one-step groove, and a width of the groove is constant in a direction from the first surface to the second surface.
10. The package structure of claim 1, wherein the opening is a one-step groove, and a width of the groove gradually increases in a direction from the first surface to the second surface.
11. The package structure according to any one of claims 1 to 10, wherein an insulating layer is provided between the interconnection metal layer and the sidewall of the opening;
and the surface of the interconnection metal layer is covered with a solder mask layer.
12. A packaging method of a fingerprint chip is characterized by comprising the following steps:
providing a wafer, wherein the wafer comprises a plurality of fingerprint chips; a cutting channel is arranged between every two adjacent fingerprint chips; the fingerprint chip comprises a first surface and a second surface which are opposite; the first surface is provided with a functional area and a peripheral area surrounding the functional area, the functional area is provided with a detection unit for detecting fingerprint information, and the peripheral area is provided with a welding pad electrically connected with the detection unit; the second surface comprises a first area arranged opposite to the functional area and a second area surrounding the first area;
forming a cavity in the first region;
fixing a sealing cover on the surface of the wafer, wherein the sealing cover covers the second surfaces of all the fingerprint chips;
carrying out graphical processing on the sealing cover and the wafer to form an opening exposing the welding pad;
forming an interconnection metal layer in the opening, wherein the interconnection metal layer is connected with the welding pad and extends to the surface of one side of the sealing cover, which is far away from the fingerprint chip, and the interconnection metal layer is used for being connected with an external circuit;
and cutting based on the cutting channel to form a plurality of single-grain fingerprint chip packaging structures.
13. The method of packaging of claim 12, wherein the forming a cavity in the first region comprises:
fixing a temporary carrier plate on the front surface of the wafer; the temporary carrier plate covers all the first surfaces of the fingerprint chips;
inverting the wafer, and horizontally placing the temporary carrier plate below the wafer;
the cavity is formed in the first region.
14. The packaging method according to claim 13, wherein the wafer and the temporary carrier are temporarily bonded and fixed by a hot melt adhesive or an optical adhesive.
15. The method of packaging of claim 13, further comprising:
removing the temporary carrier plate before cutting treatment;
or, after the cutting treatment is finished, the temporary carrier plate is removed.
16. The method of claim 12, wherein the etching the cap and the wafer comprises:
removing the part of the sealing cover corresponding to the second area to expose the second area;
and etching the wafer, and forming an opening exposing the welding pad in the second area of each chip.
17. The method of claim 16, wherein the forming of the opening comprises:
performing half-cutting treatment on the wafer, and forming a groove in the second area corresponding to the welding pad area;
and etching the wafer, and forming a through hole at the bottom of the groove, wherein the through hole exposes the welding pad.
18. The method of claim 16, wherein the forming of the opening comprises:
carrying out deep cutting treatment on the wafer, forming a groove in the second area corresponding to the welding pad area, wherein the bottom of the groove and the welding pad are provided with thin layers with the thickness smaller than the preset thickness, and etching the thin layers through an etching process to expose the welding pad; wherein the width of the groove is constant or gradually increased in a direction from the first surface to the second surface.
19. The method of claim 16, wherein the removing the portion of the cover corresponding to the second region comprises:
removing the part, corresponding to the second area, of the sealing cover through a cutting process to expose the adhesive layer between the fingerprint chip and the sealing cover, and removing the adhesive layer through a plasma process to expose the fingerprint chip;
or removing the part of the sealing cover corresponding to the second area through an etching process to expose the adhesive layer between the fingerprint chip and the sealing cover, and removing the adhesive layer through a plasma process to expose the chip.
20. The method of claim 12, wherein the forming an interconnect metal layer within the opening comprises:
forming an insulating layer in the opening, wherein the insulating layer covers the side wall of the opening and exposes the welding pad;
and forming the interconnection metal layer on the surface of the insulating layer, wherein the interconnection metal layer is electrically connected with the welding pad at the bottom of the opening and extends to the surface of the sealing cover.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811069199.8A CN109192708B (en) | 2018-09-13 | 2018-09-13 | Packaging structure and packaging method of fingerprint chip |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811069199.8A CN109192708B (en) | 2018-09-13 | 2018-09-13 | Packaging structure and packaging method of fingerprint chip |
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| Publication Number | Publication Date |
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| CN109192708A CN109192708A (en) | 2019-01-11 |
| CN109192708B true CN109192708B (en) | 2020-06-19 |
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| CN112926360A (en) * | 2019-12-05 | 2021-06-08 | 北京小米移动软件有限公司 | Fingerprint acquisition module, middle frame, terminal equipment and manufacturing method of terminal equipment |
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| US20060102974A1 (en) * | 2004-11-12 | 2006-05-18 | Chen Neng C | Contact image capturing structure |
| CN104050445B (en) * | 2014-04-08 | 2018-10-16 | 南昌欧菲生物识别技术有限公司 | Fingerprint identification device, the packaging method of fingerprint identification device and intelligent terminal |
| CN105236346B (en) * | 2015-11-13 | 2017-09-26 | 华天科技（昆山）电子有限公司 | MEMS chip encapsulating structure and preparation method thereof |
| CN106295534B (en) * | 2016-08-02 | 2023-09-08 | 苏州科阳光电科技有限公司 | Fingerprint cover plate module and manufacturing method thereof |
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