CN212848407U - Packaging structure of biological identification fingerprint chip - Google Patents
Packaging structure of biological identification fingerprint chip Download PDFInfo
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- CN212848407U CN212848407U CN202022228838.XU CN202022228838U CN212848407U CN 212848407 U CN212848407 U CN 212848407U CN 202022228838 U CN202022228838 U CN 202022228838U CN 212848407 U CN212848407 U CN 212848407U
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Abstract
The utility model discloses a biological identification fingerprint chip's packaging structure, include: the chip unit is provided with a front surface and a back surface which are opposite, and the front surface of the chip unit is provided with a sensing area; the condensing lens array is arranged on the front surface of the chip unit and comprises a plurality of micro lenses arranged in an array; the interval sets up a plurality of light shield layers between the front of chip unit and condensing lens array, and the light shield layer has seted up light-transmitting window in the light path between microlens and induction zone in order to form the collimation light path. The present case is through seting up the light trap on multilayer light shield layer, has formed the light path of collimation, can block and absorb oblique light, filters the interference of oblique light to image forming, and the spotlight effect is good.
Description
Technical Field
The utility model belongs to the technical field of the semiconductor, concretely relates to biological 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.
SUMMERY OF THE UTILITY MODEL
An embodiment of the utility model provides a packaging structure of fingerprint identification chip for the sensing result of solving different photosensitive pixels among the prior art produces and disturbs, influences the technical problem of fingerprint identification precision, include:
a package structure of a biometric fingerprint chip comprises:
the chip unit is provided with a front surface and a back surface which are opposite, and the front surface of the chip unit is provided with a sensing area;
the condensing lens array is arranged on the front surface of the chip unit and comprises a plurality of micro lenses arranged in an array;
the interval sets up a plurality of light shield layers between the front of chip unit and condensing lens array, and the light shield layer has seted up light-transmitting window in the light path between microlens and induction zone in order to form the collimation light path.
In one embodiment, the inner diameter of the light-transmissive window is smaller than the outer diameter of the microlens.
In one embodiment, an inner diameter of the light-transmitting window near the photosensitive region is smaller than an inner diameter of the light-transmitting window near the microlens.
In one embodiment, the fingerprint identification chip further comprises a light-transmitting layer, and the light-transmitting layer is supported between the light-shielding layer and the fingerprint identification chip, and/or between adjacent light-shielding layers, and/or between the condenser lens array and the light-shielding layer.
In one embodiment, the material of the light-transmitting layer is a dry film, inorganic glass or organic glass.
In one embodiment, the light-shielding layer is made of a metal material or a black photosensitive organic material.
In an embodiment, the chip unit further includes a filter layer disposed on the front surface of the chip unit.
In one embodiment, a chip unit includes:
the welding pad is positioned outside the sensing area;
a through hole penetrating the chip unit from a back surface of the chip unit opposite to the front surface, the through hole exposing the pad;
the insulating layer covers the back of the chip unit and the surface of the side wall of the through hole;
the metal layer is positioned on the surface of the insulating layer and electrically connected with the welding pad;
the solder mask is positioned on the surfaces of the metal layer and the insulating layer and is provided with an opening for exposing a part of the metal layer;
and filling the opening and exposing the external connection bump outside the surface of the solder resist layer.
Compared with the prior art, the present case is through seting up the light trap on the multilayer light shield layer, has formed the light path of collimation, can block and absorb oblique light, filters oblique light and to the fashioned interference of image, and the spotlight effect is good.
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 10 are schematic views of intermediate structures formed by the package structure in embodiment 1 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.
The present embodiment provides a package structure 10, and referring to fig. 1, the package structure 10 includes a chip unit 11, a light-transmitting layer 12, a light-shielding layer 13, and a condenser lens array 14.
The chip unit 11 has opposite front 111 and back 112 surfaces, the front surface having a sensing area 113. The sensing region 113 is provided with a plurality of pixel points for collecting image information.
The front surface 111 of the chip unit 11 is provided with a pad 114 outside the sensing region 113, in this embodiment, the chip unit 11 is further provided with: a via 115 extending from the back surface 112 to the front surface 111 of the chip unit 11, the via 115 exposing the pad 114; an insulating layer 116 on the backside 112 and on the sidewalls of the via 115; a metal wiring layer 117 located at the bottom of the insulating layer 116 and the via 115, the metal wiring layer 117 being electrically connected to the pad 114; a solder resist layer 118 positioned on the metal wiring layer 117 and the insulating layer 116, wherein an opening is formed in the solder resist layer 118, and the bottom of the opening is exposed out of the metal wiring layer 117; the solder balls 119 filling the openings, the solder balls 119 being electrically connected to the metal wiring layer 117. In this way, the pads 114 are electrically connected to the solder balls 119 through the metal wiring layer 117, and the chip unit 11 is electrically connected to other external circuits through the solder balls 119.
The light-transmitting layer 12 covers the front surface 111 of the chip unit 11, and is used for protecting the front surface of the chip unit 11 to be packaged. Because the light is required to reach the pixel point through the light-transmitting layer 12, the light-transmitting layer 12 has higher light-transmitting property and is a light-transmitting 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 light-transmitting layer 12 may be a dry film, inorganic glass, organic glass, or other light-transmitting material with a specific strength, and the transmittance needs to be more than 92%.
The condenser lens array 14 is supported on the surface of the transparent layer 12, and includes a plurality of microlenses arranged in an array, and the microlenses are used for converging external light to the surfaces of corresponding pixels.
In one embodiment, the condenser lens array 14 may be fabricated by photolithography and baking, and in another embodiment, the condenser lens array 14 may also be formed on the surface of the transparent layer 12 by stamping.
In order to realize that the received light of a pixel point can only be direct light, ensure the image definition, filter the image forming interference of oblique light, the light shielding layer 13 is formed with a collimated light path structure, specifically, the light shielding layer 13 comprises a first light shielding layer 131 and a second light shielding layer 132 which are arranged at intervals, a plurality of light transmission windows 133 arranged in an array are respectively arranged on the first light shielding layer 131 and the second light shielding layer 132, and each light transmission window 133 corresponds to a micro lens respectively.
In this technical scheme, light converges through the microlens, and the converged light sequentially passes through a light-transmitting window on the second light-shielding layer 132 and a light-transmitting window on the first light-shielding layer 131, and then enters the corresponding pixel region.
In a direction perpendicular to the front surface 111 of the chip unit 11, projections of the light-transmitting windows 133 on all the light-shielding layers on the front surface 111 of the chip unit 11 at least partially overlap with projections of corresponding pixel points on the front surface 111. In order to ensure the accuracy of fingerprint identification, the projection of the light-transmitting window 133 on the front 111 may be set to completely cover the projection of the corresponding pixel point on the front 111. Optimally, the projection of the light-transmitting window 133 on the front 111 and the projection of the corresponding pixel point on the front 111 may be completely overlapped.
In other embodiments, the light-shielding layer 13 may be provided with not only 2 layers, but also 3 or more layers, and a plurality of light-shielding layers may be provided, in which light-transmitting windows formed therein correspond in the optical path direction to form a collimating structure.
The shape of the light-transmissive window 133 may be circular or square or triangular. Specifically, the shape of the light-transmitting window 133 may be a circular cylinder with the same top and bottom, a square cylinder with the same top and bottom, a triangular cylinder with the same top and bottom, or a polygonal cylinder with the same top and bottom in other structures.
It is easy to think that the shape of the light-transmitting window 133 can be a circular cylinder with different top and bottom, a square cylinder with different top and bottom, a triangular cylinder with different top and bottom, or a polygonal cylinder with different top and bottom.
In other embodiments, the light-shielding layers of different layers may also be provided with light-transmitting windows of different shapes; the light shield layers on different layers can also be made of different materials, for example, the first light shield layer material is made of aluminum, the second light shield layer material is made of BLK black glue, and the metal is a strong reflection layer and is positioned on the lower layer to reduce the entering of stray light and reduce the influence on light receiving of pixel points.
In an embodiment, the light-transmitting windows of the light-shielding layers of different layers have different sizes, and preferably, the inner diameter of the light-transmitting window near the photosensitive region is smaller than the inner diameter of the light-transmitting window near the microlens. So set up, can reduce the requirement of printing opacity window position precision (printing opacity window counterpoint precision on the positive direction of perpendicular to chip unit on the different light shield layers), in addition through different printing opacity window designs, can reduce stray light's interference, the effective light is passed through perpendicularly.
In one embodiment, the light-shielding layer is made of a material selected from a metal or a black photosensitive organic material. The metal can be aluminum, and the black photosensitive organic material can be BKL black glue.
In order to support the light-shielding layer, the light-transmitting layer 12 includes a first light-transmitting layer 121, a second light-transmitting layer 122, and a third light-transmitting layer 123, and the first light-transmitting layer 121, the second light-transmitting layer 122, and the third light-transmitting layer 123 are stacked in this order and formed on the front surface 111 of the chip unit 11. The first light-shielding layer 131 is formed between the front surface 111 of the first light-transmitting layer 121 and the second light-transmitting layer 122, and the second light-shielding layer 132 is formed between the second light-transmitting layer 122 and the third light-transmitting layer 123. The condenser lens array 14 is supported on the surface of the third light-transmitting layer 123.
In one embodiment, a filter layer 15 is further disposed between the light-transmissive layer 12 and the front surface 111 of the chip unit 11.
The filter layer 15 is used to filter stray light outside the detection light band, so as to reduce stray light interference and improve fingerprint identification accuracy.
The filter layer 15 may cover only the upper portions corresponding to the pixel points, or may cover the entire front surface 111 of the chip unit 11. However, in order to facilitate the fabrication of the light-transmitting layer 12 and ensure the flatness thereof, the filter layer 15 preferably covers the entire front surface 111 of the chip unit 11.
In one embodiment, the filter layer 15 and the first transparent layer 121 are fixed by bonding with a DAF film. The first light-transmitting layers 121 and the front surface 111 of the chip unit 11 are fixed by adhesive.
In this case, the filter layer 15 is optional, and in an embodiment, the filter layer may not be provided.
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. 9, which are schematic diagrams of intermediate structures formed in the packaging process of the packaging method according to an embodiment of the present invention.
Step s 1: referring to fig. 2 and 3, a wafer to be packaged is provided, in which fig. 2 is a schematic top view of the wafer to be packaged, and fig. 3 is a cross-sectional view taken along a-a in fig. 2 (for example, a single chip unit).
The wafer to be packaged has a front side 111 and a back side 112 opposite to the front side 111. The wafer 100 includes a plurality of chip units 11 arranged in an array. The adjacent fingerprint identification chips 11 have a cutting channel 110 therebetween to facilitate a cutting process in a subsequent cutting process.
The front surface 111 comprises a sensing area 113 and a non-sensing area surrounding the sensing area, the pixel points are arranged in the sensing area, the non-sensing area is provided with a bonding pad 15, the bonding pad is electrically connected with the pixel points, and the bonding pad is used for being electrically connected with an external circuit.
It should be noted that the cutting channel 110 between two adjacent chip units 11 is only a margin area reserved between two chip units 11 for cutting, and there is no actual boundary line between the cutting channel 110 and the chip units 11 on both sides.
Step s 2: referring to fig. 4, the front surface 111 of the wafer 100 to be packaged is covered with the filter layer 15. In this step, the filter layer 15 is fixed on the surface of the wafer 100 to be packaged by adhesive.
Step s 3: referring to fig. 5, the surface of the filter layer 15 is covered with a first light-transmitting layer 121.
Step s 4: referring to fig. 6, a first light-shielding layer 131 is formed on the first light-transmitting layer 121, and may be patterned by a photolithography process to form light-transmitting windows 133 distributed in an array, where each light-transmitting window corresponds to a pixel point;
step s 5: referring to fig. 7, a second light-transmitting layer 122 is formed over the surfaces of the first light-transmitting layer 121 and the first light-shielding layer 131;
step s 6: referring to fig. 8, a second light-shielding layer 132 is formed on the second light-transmitting layer 122, and may be patterned by a photolithography process to form light-transmitting windows 133 distributed in an array, where each light-transmitting window corresponds to a pixel point;
step s 7: referring to fig. 9, a third light-transmitting layer 123 is formed over the surfaces of the second light-transmitting layer 122 and the second light-shielding layer 132;
step s 8: referring to fig. 10, a condensing lens array 14 is formed on the surface of the third light-transmitting layer 123, each microlens corresponds to a pixel point, the light path where the microlens and the corresponding pixel point are located is perpendicular to the front surface of the chip unit, and light can enter the pixel point through the microlenses and the light-transmitting windows on the plurality of light-shielding layers in sequence.
Step s 9: referring to fig. 1, a through hole is etched in the back surface of the chip unit, and an insulating layer, a metal layer, a solder resist layer, and an external bump are sequentially formed.
Step s 10: the wafer 100 is divided by a dicing process, and when dicing is performed, dicing is performed along a direction of the dicing channels 110, thereby forming a plurality of package structures 10. 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.
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).
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 (8)
1. A packaging structure of a biological identification fingerprint chip is characterized by comprising:
the chip unit is provided with a front surface and a back surface which are opposite, and the front surface of the chip unit is provided with a sensing area;
the condensing lens array is arranged on the front surface of the chip unit and comprises a plurality of micro lenses arranged in an array;
the interval sets up a plurality of light shield layers between the front of chip unit and condensing lens array, and the light shield layer has seted up light-transmitting window in the light path between microlens and induction zone in order to form the collimation light path.
2. The package structure of claim 1, wherein an inner diameter of the light-transmissive window is smaller than an outer diameter of the micro lens.
3. The package structure of claim 1, wherein an inner diameter of the light-transmissive window near the sensing region is smaller than an inner diameter of the light-transmissive window near the micro-lens.
4. The package structure of claim 1, further comprising a light-transmissive layer supported between the light-shielding layer and the fingerprint recognition chip, and/or between adjacent light-shielding layers, and/or between the condensing lens array and the light-shielding layer.
5. The package structure of biometric fingerprint chip of claim 1, wherein the material of the transparent layer is a dry film, inorganic glass or organic glass.
6. The package structure of biometric fingerprint chip of claim 1, wherein the light shielding layer is made of a metal material or a black photosensitive organic material.
7. The package structure of biometric fingerprint chip of claim 1, further comprising a filter layer disposed on the front surface of the chip unit.
8. The package structure of biometric fingerprint chip of claim 1, wherein the chip unit comprises:
the welding pad is positioned outside the sensing area;
a through hole penetrating the chip unit from a back surface of the chip unit opposite to the front surface, the through hole exposing the pad;
the insulating layer covers the back of the chip unit and the surface of the side wall of the through hole;
the metal layer is positioned on the surface of the insulating layer and electrically connected with the welding pad;
the solder mask is positioned on the surfaces of the metal layer and the insulating layer and is provided with an opening for exposing a part of the metal layer;
and filling the opening and exposing the external connection bump outside the surface of the solder resist layer.
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CN202022228838.XU CN212848407U (en) | 2020-10-09 | 2020-10-09 | Packaging structure of biological identification fingerprint chip |
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CN202022228838.XU CN212848407U (en) | 2020-10-09 | 2020-10-09 | Packaging structure of biological identification fingerprint chip |
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