CN211555899U - Packaging structure of fingerprint identification chip - Google Patents

Abstract

The utility model discloses a packaging structure, this packaging structure includes: a first light transmitting layer having opposing first and second surfaces; the first assembly is attached to the first surface of the first light-transmitting layer and comprises a fingerprint identification chip, and the surface, close to the first light-transmitting layer, of the fingerprint identification chip is provided with a plurality of pixel points for collecting fingerprint information; the second assembly is pasted on the second surface of the first euphotic layer and comprises a first light shading layer and a second euphotic layer, the first light shading layer is formed between the second euphotic layer and the first euphotic layer, a plurality of light holes are formed in the first light shading layer, and each light hole corresponds to one pixel point respectively. The utility model discloses make two wafer level important parts earlier, then laminate it mutually, reduce the processing degree of difficulty, easy volume production, it is with low costs.

Description

Packaging structure of fingerprint identification chip

Technical Field

The utility model belongs to the technical field of the semiconductor, concretely relates to fingerprint identification chip packaging structure.

Background

With the continuous progress of science and technology, more and more electronic devices are widely applied to the daily life and work of people, bring great convenience to the daily life and work of people, and become an indispensable important tool for people at present. With the increasing functions of electronic devices, the electronic devices store more and more important information, and the authentication technology of electronic devices becomes a main direction for the research and development of electronic devices.

The fingerprint has uniqueness and invariance, so that the fingerprint identification technology has the advantages of good safety, high reliability, simplicity in use and the like. Therefore, fingerprint identification technology is the mainstream technology for authentication of various electronic devices.

At present, an optical fingerprint identification chip is one of fingerprint identification chips commonly used in existing electronic devices, and collects fingerprint information of a user through a large number of photosensitive pixels (pixels) in a fingerprint identification area, and each photosensitive pixel is used as a detection. Specifically, when fingerprint identification is carried out, light irradiates to the fingerprint surface of a user and is reflected to photosensitive pixels through the fingerprint surface, the photosensitive pixels convert optical signals of fingerprints into electric signals, and fingerprint information can be acquired according to the electric signals converted by all the pixels.

When the existing optical fingerprint identification chip is packaged, a transparent cover plate is generally directly arranged on the photosensitive side. However, the transparent cover plate is completely transparent, which may cause crosstalk in the sensing results of different photosensitive pixels, and affect the fingerprint identification accuracy.

To solve the technical problem, chinese patent application CN108022904A discloses a method for packaging a fingerprint identification chip, in which a cover plate having a through hole structure is fixed on a side of a wafer facing a pixel point to avoid the crosstalk problem. The problems that exist at least include: through holes on the cover plate need to be formed in advance, and then the cover plate with the through holes is combined on the surface of the chip, but the operation process time is long, and the through holes and pixel points need to be subjected to position calibration, so that errors are easy to generate; if the through hole is manufactured after the cover plate is combined with the chip, no barrier exists between the cover plate and the chip, and pixel points below the through hole are easily damaged.

In addition, in the prior art, in order to improve the packaging efficiency, a wafer level package is usually adopted, and most or all of the package test procedures are directly performed on a wafer in the wafer level package, and then the wafer level package is cut (singulated) to form a single component. The problem exists in that when a certain packaging procedure or a part of packaging positions are defective, the whole packaging structure is scrapped, and the cost is high.

SUMMERY OF THE UTILITY MODEL

An embodiment of the utility model provides a packaging structure of fingerprint identification chip for solve among the prior art processing cost height, pixel receive the technical problem of harm easily, include:

the embodiment of the application provides a packaging structure of fingerprint identification chip, includes:

a first light transmitting layer having opposing first and second surfaces;

the first assembly is attached to the first surface of the first light-transmitting layer and comprises a fingerprint identification chip, and the surface, close to the first light-transmitting layer, of the fingerprint identification chip is provided with a plurality of pixel points for collecting fingerprint information;

the second assembly is pasted on the second surface of the first euphotic layer and comprises a first light shading layer and a second euphotic layer, the first light shading layer is formed between the second euphotic layer and the first euphotic layer, a plurality of light holes are formed in the first light shading layer, and each light hole corresponds to one pixel point respectively.

Preferably, in the above package structure of the fingerprint identification chip, the first component further includes an optical filter formed between the fingerprint identification chip and the first transparent layer.

Preferably, in the above fingerprint identification chip package structure, the optical filter is attached to a surface of the fingerprint identification chip.

Preferably, in the above fingerprint identification chip package structure, the second assembly further includes a condenser lens formed on a surface of the second transparent layer, the condenser lens and the first light shielding layer are respectively located on two opposite surfaces of the second transparent layer,

each condensing lens corresponds to one light hole respectively.

Preferably, in the above fingerprint identification chip package structure, the first light shielding layer is made of monocrystalline silicon, polycrystalline silicon, amorphous silicon, silicon germanium, or silicon carbide.

Preferably, in the above-mentioned packaging structure of the fingerprint identification chip, the first light-transmitting layer and the second light-transmitting layer are selected from a dry film, inorganic glass or organic glass.

Preferably, in the above package structure of the fingerprint identification chip, the second component includes a second light shielding layer, the second light shielding layer and the first light shielding layer are formed on two opposite surfaces of the second light transmissive layer,

the second shading layer is provided with a plurality of windows, and each window corresponds to one light hole.

Compared with the prior art, the beneficial effects of the utility model include at least:

(1) the cylindrical light-shading body formed by the utility model can better shade and absorb the excessive oblique light, so that the formed image of the object is clearer;

(2) the utility model discloses make two wafer level important parts earlier, then laminate it mutually, reduce the processing degree of difficulty, easy volume production, it is with low costs.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be 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 some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a sectional view of a package structure in embodiment 1 of the present application;

fig. 2 to 7 are schematic views of intermediate structures formed by the package structure in embodiment 1 of the present application;

fig. 8 is a schematic view of an intermediate structure formed by the package structure in embodiment 2 of the present application.

Detailed Description

The present invention will be more fully understood from the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed embodiment.

Referring to fig. 1, the package structure 10 includes a first component 11, a first light-transmitting layer 12, and a second component 13, where the first component 11 and the second component 13 are respectively attached to two opposite surfaces of the first light-transmitting layer 12.

The first component 11 includes a fingerprint identification chip 111, the fingerprint identification chip 111 has opposite front and back surfaces, and the front surface of the fingerprint identification chip 111 has a plurality of pixel points 1111 for collecting fingerprint information.

The front surface of the fingerprint identification chip 111 includes a sensing area and a non-sensing area surrounding the sensing area. The pixel point 1111 is arranged in the sensing area; the non-sensing area is provided with a bonding pad (not shown) electrically connected with the pixel 1111, and the bonding pad is used for being electrically connected with an external circuit.

In one embodiment, the fingerprint identification chip 111 is an optical fingerprint identification chip.

In one embodiment, the first component 11 further includes a filter 112, and the filter 112 covers the surface of the fingerprint identification chip 111 having the pixel points.

The optical filter 112 is used for filtering out stray light outside the detection light band, so as to reduce stray light interference and improve fingerprint identification accuracy.

The filter 112 may cover only the upper side corresponding to the pixel 1111, or may cover the entire surface of the fingerprint identification chip 111.

The first light-transmitting layer 12 covers one side of the fingerprint identification chip 111 having the pixel points 1111, and is used for protecting the front side of the fingerprint identification chip 111 to be packaged. Because it is required that light passes through first euphotic layer 12 and reaches pixel 1111, consequently, euphotic layer 12 has higher light transmissivity, is the printing opacity material. Both surfaces of the light transmission layer 12 are flat and smooth, and do not generate scattering, diffuse reflection and the like on incident light.

Specifically, the material of the first light-transmitting layer 12 may be a dry film, inorganic glass, organic glass, or other light-transmitting material with a specific strength.

In this embodiment, the thickness of the first light-transmitting layer 12 is preferably 5 to 20 μm in consideration of both the optical properties and the adhesive properties of the first light-transmitting layer 12.

The second component 13 includes a light-shielding layer 131 and a second light-transmitting layer 132, and the light-shielding layer 131 is formed between the second light-transmitting layer 132 and the first light-transmitting layer 12.

The light-shielding layer 131 is provided with a plurality of light holes 1311 which are vertically communicated, each light hole 1311 corresponds to one pixel 1111, and in a preferred embodiment, the axis of the light hole 1311 coincides with the center of the pixel 1111.

The light-shielding layer 131 has a low dielectric constant, and the material of the light-shielding layer 131 is preferably a silicon material, which may be monocrystalline silicon, polycrystalline silicon, amorphous silicon, silicon germanium, or silicon carbide. The light-shielding layer 131 may be formed on the surface of the second light-transmitting layer 132 by physical deposition.

The thickness of the light-shielding layer 131 is preferably 4-20 μm, and the size of the light-transmitting holes can be adjusted according to the requirement, for example, when the light-transmitting holes are circular holes, the aperture can be 30 μm, and the aspect ratio can be 1: 1.

The light-shielding layer 131 is made of a silicon material, so that the crosstalk problem between the adjacent pixels 1111 can be reduced. On the other hand, the mohs hardness of the light-shielding layer 131 made of silicon material is generally above 10, the hardness is high, the mechanical strength is high, and the thickness deformation cannot be generated when a finger presses the light-shielding layer, so that the accuracy of fingerprint identification cannot be influenced.

In the direction perpendicular to the front surface of the fingerprint identification chip 111, the projection of the light transmission hole 1311 on the front surface at least partially overlaps with the projection of the corresponding pixel 1111 on the front surface. In order to ensure the accuracy of fingerprint identification, the projection of the light transmission hole 1311 on the front surface may be set to completely cover the projection of the corresponding pixel 1111 on the front surface. Optimally, the projection of the light transmission hole 1311 on the front surface and the projection of the corresponding pixel 1111 on the front surface may be completely overlapped.

If fingerprint identification chip 111 is the fingerprint identification chip of electric capacity type, when carrying out fingerprint identification, pixel 1111 detects the capacitance value, converts the capacitance value into the signal of telecommunication, and external circuit can acquire fingerprint information according to this signal of telecommunication, carries out identity identification, and light trap 1311 is used for exposing the pixel, light shield layer 131 have lower dielectric constant, can reduce the problem of crosstalking between the adjacent pixel, has improved fingerprint identification's accuracy.

If the fingerprint identification chip 111 is an optical fingerprint identification chip, when fingerprint identification is performed, the pixel 1111 collects fingerprint information of a preset collection area corresponding to the light hole 1311 through the corresponding light hole 1311. Because every pixel 1111 all gathers the fingerprint information in the collection region that self is relative through corresponding light trap 1311, avoided different pixels to correspond the mutual crosstalk between the preset region, and then avoided fingerprint image's distortion, further improved fingerprint identification's accuracy.

The shape of the light transmission hole 1311 may be a circular through hole or a square through hole or a triangular through hole. Specifically, the shape of the light transmitting hole 1311 may be a circular hole with the same top and bottom, a square hole with the same top and bottom, a triangular hole with the same top and bottom, or a polygon with the same top and bottom. The bottom of light transmission hole 1311 is the opening that light transmission hole 1311 is close to pixel 1111, and the top of light transmission hole 1311 is the opening that light transmission hole 1311 keeps away from pixel 1111.

It is easy to think that the shape of the light transmitting hole 1311 may be a circular hole with different top and bottom, a square hole with different top and bottom, a triangular hole with different top and bottom, or a polygon with different top and bottom. At this time, the top of the light transmission hole 1311 is larger than the bottom of the light transmission hole 1311. Similarly, the bottom of the light hole 1311 is an opening of the light hole 1311 close to the pixel 1111, and the top of the light hole 1311 is an opening of the light hole 1311 far from the pixel 1111.

In one embodiment, the light-shielding layer 131 and the first light-transmitting layer 12 are fixed by bonding with a DAF film.

The second light-transmitting layer 132 covers a surface of the light-shielding layer 131 away from the fingerprint identification chip 111, and is used for shielding an opening of the light-transmitting hole 1311. Since the light is required to reach the pixel point 1111 through the second transparent layer 132, the second transparent layer 132 has a higher light transmittance and is a transparent material. The two surfaces of the second light-transmitting layer 132 are flat and smooth, and do not scatter or diffuse incident light.

Specifically, the material of the second light-transmitting layer 132 may be a dry film, inorganic glass, organic glass, or other light-transmitting material with a specific strength.

In this embodiment, the thickness of the second light-transmitting layer 132 is preferably 10 to 40 micrometers.

In one embodiment, the second transparent layer 132 and the light-shielding layer 131 are fixed by an adhesive.

The second assembly 13 further includes a condensing lens 133, the condensing lens 133 is disposed on a side of the second transparent layer 132 away from the fingerprint identification chip 111, each condensing lens 133 corresponds to one of the transparent holes 1311, and the condensing lens 133 is configured to condense external light to the surface of the corresponding pixel 1111.

In one embodiment, the condensing lens 133 may be fabricated by photolithography and baking, and in another embodiment, the condensing lens 133 may also be formed on the surface of the second transparent layer 132 by stamping.

The second assembly further includes a light-shielding layer 134, wherein the light-shielding layer 134 and the light-shielding layer 131 are formed on two opposite surfaces of the second light-transmitting layer, and a plurality of windows are formed on the second light-shielding layer 134, and each window corresponds to one of the light-transmitting holes. The condensing lens 133 is correspondingly disposed within the window.

The light shielding layer 134 is formed between the condensing lenses 133, so that interference of light around the condensing lenses can be shielded, and an imaging effect can be optimized.

In this embodiment, the light-shielding layer 134 is made of a black photosensitive organic material or a blackened metal, and has a characteristic of light-proof or low light-transmission. For example, the light-shielding layer 134 may be black glue; the light-shielding layer 134 may also be blackened aluminum, so that light cannot form mirror reflection on its surface, and the light-shielding performance is good.

Correspondingly, the embodiment of the invention provides a packaging method for forming the packaging structure shown in fig. 1.

Please refer to fig. 2 to fig. 7, which are schematic intermediate structural diagrams formed in the packaging process of the packaging method according to the first embodiment of the present invention.

Step s 1: a first wafer level package structure is fabricated.

Referring to fig. 2 and 3, a wafer 100 to be packaged is provided, wherein fig. 2 is a schematic top view of the wafer 100 to be packaged, and fig. 3 is a cross-sectional view taken along a-a in fig. 2.

The wafer 100 to be packaged has a front side and a back side opposite to the front side. The wafer 100 includes a plurality of fingerprint identification chips 111 arranged in an array. Each adjacent fingerprint identification chip 111 has a plurality of pixel points 1111 for collecting fingerprint information. Pixel 1111 is located on the front side. The adjacent fingerprint identification chips 111 have a cutting channel 120 therebetween to facilitate a cutting process in a subsequent cutting process.

It should be noted that the cutting channel 120 between two adjacent fingerprint identification chips 111 only provides a margin area for cutting between two fingerprint identification chips 111, and there is no actual boundary line between the cutting channel 120 and the fingerprint identification chips 111 on both sides.

Referring to fig. 4, the front surface of the wafer 100 to be packaged is covered with the optical filter 112, and the optical filter 112 covers the entire surface of the fingerprint identification chip 111, so as to obtain a first package structure.

Step s 2: a single first component 11 is made.

The first package structure is diced along the dicing channels 120 to obtain a plurality of individual first components 11. The cutting can be performed by a slicing knife or a laser cutting, and the slicing knife can be performed by a metal knife or a resin knife.

Step s 3: and manufacturing a second wafer-level packaging structure.

Referring to fig. 5, a plurality of light-transmitting holes 1311 are formed in the light-shielding layer 131 to be vertically communicated with each other, and then the light-shielding layer 131 is attached to the surface of the second light-transmitting layer 132.

Referring to fig. 6, the light-shielding layer 134 is formed on the other surface of the second light-transmitting layer 132, and a plurality of windows are formed on the light-shielding layer 134 corresponding to the light-transmitting holes.

Then, the condensing lenses 133 are installed corresponding to the windows, and each condensing lens 133 corresponds to one light transmission hole 1311, respectively, thereby obtaining a second package structure.

Note that, in this embodiment, the order of manufacturing the light-shielding layer 134 and the light-collecting lens 133 is not limited, and the order of manufacturing the light-shielding layer 131 and the light-shielding layer 134 is also not limited in this embodiment.

Step s 4: a single second component is fabricated.

The second package structure is correspondingly divided along the dicing channels 120 by a dicing process to obtain individual second components 13. The cutting can be performed by a slicing knife or a laser cutting, and the slicing knife can be performed by a metal knife or a resin knife.

Step s 5: referring to fig. 7, the first and second components that pass the screening test are individually adhered to opposite surfaces of the first light transmitting layer.

The adhering can be realized by forming an adhesive layer through spraying, spin coating or adhering, then pressing the first assembly, the second assembly and the first light-transmitting layer relatively, and combining through the adhesive layer. The adhesive layer can realize the adhesive function and also can play the insulating and sealing functions. The adhesive layer may be a polymer adhesive material, such as a polymer material, e.g., silicone, epoxy, benzocyclobutene, etc.

In the whole packaging process, the processes of wafer thinning, bonding pad manufacturing, wiring layer manufacturing and the like can be included, and the scheme is not repeated.

In addition, after the wafer to be packaged is packaged, the chip package structure obtained by subsequent cutting can be connected with an external circuit through an external bump (not shown).

Please refer to fig. 8, which is a schematic diagram of an intermediate structure formed in the packaging process of the packaging method according to the second embodiment of the present invention.

Different from the first embodiment, after the single second assembly 13 is cut, the second assembly is attached to the first wafer-level package structure through the first transparent layer 12; and then cutting the first packaging structure to obtain the packaging structure combined by the single first assembly and the single second assembly.

In the packaging method of the third embodiment, compared to the first embodiment, the wafer 100 to be packaged is cut into a plurality of units, and then the surface of each unit is plated with the optical filter 112, so as to form a single first component 11. In the packaging method of the fourth embodiment, the wafer-level first package structure and the wafer-level second package structure may be fabricated first, then the wafer-level first package structure and the wafer-level second package structure are respectively attached to two surfaces of the first transparent layer, and finally the single package structure is obtained by cutting.

The aspects, embodiments, features and examples of the present invention should be considered illustrative in all respects and not intended to be limiting, the scope of the invention being defined only by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

The use of headings and chapters in this application is not meant to limit the invention; each section may apply to any aspect, embodiment, or feature of the present invention.

Throughout this application, where a composition is described as having, containing, or comprising specific components or where a process is described as having, containing, or comprising specific process steps, it is contemplated that the compositions taught by the present invention also consist essentially of, or consist of, the recited components, and that the processes taught by the present invention also consist essentially of, or consist of, the recited process steps.

In this application, where an element or component is referred to as being included in and/or selected from a list of recited elements or components, it is understood that the element or component can be any one of the recited elements or components and can be selected from a group consisting of two or more of the recited elements or components. Moreover, it should be understood that elements and/or features of the compositions, apparatus, or methods described herein may be combined in various ways, whether explicitly described or implicitly described herein, without departing from the spirit and scope of the present teachings.

Unless specifically stated otherwise, use of the terms "comprising", "including", "having" or "having" is generally to be understood as open-ended and not limiting.

The use of the singular herein includes the plural (and vice versa) unless specifically stated otherwise. Furthermore, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. In addition, where the term "about" is used before a quantity, the teachings of the present invention include the particular quantity itself unless specifically stated otherwise.

It should be understood that the order of steps or the order in which particular actions are performed is not critical, so long as the teachings of the present invention remain operable. Further, two or more steps or actions may be performed simultaneously.

It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity, other elements. However, those skilled in the art will recognize that these and other elements may be desirable. However, because such elements are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements is not provided herein. It should be understood that the figures are presented for illustrative purposes and not as construction diagrams. The omission of details and modifications or alternative embodiments is within the scope of one skilled in the art.

It is to be understood that in certain aspects of the present invention, a single component may be replaced by multiple components and that multiple components may be replaced by a single component to provide an element or structure or to perform a given function or functions. Such substitutions are considered to be within the scope of the present invention, except where such substitution would not operate to practice a particular embodiment of the invention.

While the invention has been described with reference to illustrative embodiments, it will be understood by those skilled in the art that various other changes, omissions and/or additions may be made and substantial equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated any use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.

Claims (7)

1. A packaging structure of a fingerprint identification chip is characterized by comprising:

a first light transmitting layer having opposing first and second surfaces;

the first assembly is attached to the first surface of the first light-transmitting layer and comprises a fingerprint identification chip, and the surface, close to the first light-transmitting layer, of the fingerprint identification chip is provided with a plurality of pixel points for collecting fingerprint information;

the second assembly is pasted on the second surface of the first euphotic layer and comprises a first light shading layer and a second euphotic layer, the first light shading layer is formed between the second euphotic layer and the first euphotic layer, a plurality of light holes are formed in the first light shading layer, and each light hole corresponds to one pixel point respectively.

2. The package structure of the fingerprint identification chip of claim 1, wherein the first component further comprises a filter formed between the fingerprint identification chip and the first transparent layer.

3. The package structure of fingerprint identification chip of claim 1, wherein the filter is adhered to the surface of the fingerprint identification chip.

4. The package structure of the fingerprint identification chip of claim 1, wherein the second assembly further comprises a condensing lens formed on a surface of the second transparent layer, the condensing lens and the first light shielding layer are respectively disposed on two opposite surfaces of the second transparent layer,

each condensing lens corresponds to one light hole respectively.

5. The package structure of the fingerprint identification chip of claim 1, wherein the first light shielding layer is made of monocrystalline silicon, polycrystalline silicon, amorphous silicon, silicon germanium, or silicon carbide.

6. The package structure of the fingerprint identification chip of claim 1, wherein the first and second transparent layers are selected from a dry film, inorganic glass, or organic glass.

7. The package structure of fingerprint identification chip of claim 1, wherein the second assembly comprises a second light shielding layer, the second light shielding layer and the first light shielding layer are formed on two opposite surfaces of the second light transmissive layer,

the second shading layer is provided with a plurality of windows, and each window corresponds to one light hole.

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