CN104182736B - Fingerprint Identification sensor encapsulating structure and method for packing - Google Patents

Abstract

Embodiments of the present invention provide a fingerprint recognition sensor packaging structure and packaging method, the packaging structure includes: a fingerprint recognition sensor disposed above a silicon wafer and electrically connected to the silicon wafer; a color sensor disposed above the fingerprint recognition sensor film layer; a hard mask layer arranged above the color film layer; a substrate arranged below the silicon wafer; wherein, at least one layer of the hard mask layer and the color film layer is doped with a high dielectric Electric particles. The packaging structure provided in this embodiment can improve the recognition accuracy of the fingerprint recognition sensor.

Description

Encapsulation structure and encapsulation method of fingerprint recognition sensor

technical field

The embodiment of the present invention relates to a biometric identification module packaging technology, in particular to a fingerprint identification sensor packaging structure and packaging method.

Background technique

With the development of science and technology, electronic sensing technology is being applied more and more. At present, the fingerprint identification (finger printing) technology implemented by electronic sensing technology is the most mature and cheap biometric identification technology, which can be applied to notebook computers, mobile phones, automobiles, banks and other fields.

In the prior art, the fingerprint recognition sensor realized by the biometric identification technology is mainly a matrix-type capacitive fingerprint recognition sensor formed by a Complementary Metal Oxide Semiconductor (CMOS) process.

However, due to the existing capacitive fingerprint recognition sensor packaging structure, the fingerprint recognition sensor is placed under the control button or display element where the capacitive sensing is not obvious, so that the capacitance sensing effect of the capacitive fingerprint recognition sensor is not obvious, resulting in the capacitive fingerprint recognition. The recognition accuracy of the sensor is not high.

Contents of the invention

Embodiments of the present invention provide a fingerprint recognition sensor packaging structure and packaging method, so as to improve the recognition accuracy of the fingerprint recognition sensor.

In the first aspect, an embodiment of the present invention provides a fingerprint identification sensor packaging structure, including:

A fingerprint identification sensor arranged above the silicon wafer and electrically connected to the silicon wafer;

a color film layer arranged above the fingerprint recognition sensor;

a hard mask layer arranged above the color film layer;

a substrate disposed below the silicon wafer;

Wherein, at least one of the hard mask layer and the color film layer is doped with high dielectric particles.

In a second aspect, an embodiment of the present invention provides a fingerprint identification sensor packaging method, including:

A fingerprint identification sensor is arranged above the silicon wafer, and the fingerprint identification sensor is electrically connected to the silicon wafer;

Setting a color film layer above the fingerprint recognition sensor;

A hard mask layer is arranged above the color film layer, at least one of the hard mask layer and the color film layer is doped with high dielectric particles;

The silicon wafer is disposed on a substrate.

The packaging structure and packaging method of the fingerprint recognition sensor provided by this embodiment, the packaging structure includes: a fingerprint recognition sensor arranged above the silicon wafer and electrically connected to the silicon wafer; a color film layer arranged above the fingerprint recognition sensor; The hard mask layer arranged above the film layer; the substrate arranged below the silicon wafer, wherein, in the hard mask layer or the color film layer, at least one layer is doped with high dielectric particles, so that not only the fingerprint recognition sensor is Capacitive sensing is more obvious, which can improve the recognition accuracy of the fingerprint recognition sensor, and can also increase the recognition distance of the fingerprint recognition sensor.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is a schematic cross-sectional view of the package structure of the fingerprint recognition sensor of the present invention;

FIG. 2 is a schematic diagram of a fingerprint recognition scene according to the present invention;

Fig. 3 is the principle schematic diagram of fingerprint identification of the present invention;

FIG. 4 is a second schematic cross-sectional view of the packaging structure of the fingerprint identification sensor of the present invention;

5 is a schematic cross-sectional view III of the package structure of the fingerprint recognition sensor of the present invention;

6 is a schematic cross-sectional view four of the package structure of the fingerprint recognition sensor of the present invention;

7 is a schematic cross-sectional view five of the package structure of the fingerprint identification sensor of the present invention;

FIG. 8 is a schematic flow diagram of Embodiment 1 of the packaging method of the fingerprint identification sensor of the present invention;

Fig. 9 is a schematic cross-sectional view VII of the packaging structure of the fingerprint identification sensor of the present invention;

10 is a schematic cross-sectional view eight of the packaging structure of the fingerprint recognition sensor of the present invention;

Fig. 11 is a schematic cross-sectional view nine of the package structure of the fingerprint recognition sensor of the present invention;

FIG. 12 is a schematic flowchart of Embodiment 1 of the method for packaging a fingerprint identification sensor of the present invention.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

FIG. 1 is a first schematic cross-sectional view of the packaging structure of the fingerprint identification sensor of the present invention. The fingerprint recognition sensor provided in this embodiment can specifically be a capacitive fingerprint recognition sensor, and can be used in electronic devices, such as smart phones, touch panels, mobile computing devices, electrical appliances, panels or bodies of vehicles, and the like. As shown in Figure 1, the package structure of the fingerprint identification sensor provided in this embodiment includes:

A fingerprint identification sensor 103 arranged above the silicon wafer 102 and electrically connected to the silicon wafer 102;

The color film layer 104 arranged above the fingerprint identification sensor 103;

a hard mask layer 105 arranged above the color film layer 104;

A substrate 101 disposed below the silicon wafer 102 .

In this embodiment, the silicon wafer 102 and the fingerprint recognition sensor 103 are provided independently, and the silicon wafer 102 and the fingerprint recognition sensor 103 are electrically connected. Through the independent arrangement of the silicon wafer 102 and the fingerprint identification sensor 103 , the requirements for the silicon wafer 102 are lower, so that the cost of the packaging structure of the fingerprint identification sensor is lower.

The color film layer 104 provided on the fingerprint recognition sensor 103 not only has a color effect, but also can make the components of the fingerprint recognition sensor not immediately visible to the user.

The hard mask layer 105 disposed on the color film layer 104 has a flatness of less than 10 μm. The hard mask layer 105 is mainly used to protect the fingerprint recognition sensor and the silicon wafer, preventing the user from damaging the fingerprint recognition sensor and the silicon wafer under countless presses or abnormal presses. Those skilled in the art can understand that the packaging structure of the fingerprint recognition sensor provided in this embodiment can also be used in conjunction with the control button, and the control button can be placed on the hard mask layer 105. At this time, the top of the hard mask layer 105 has a concave The shape is such that when the user's finger is guided into the concave shape, the user's finger can be well positioned for fingerprint recognition.

Furthermore, in the hard mask layer or the color film layer provided in this embodiment, at least one layer is doped with high dielectric particles. The doped high dielectric particles can improve the capacitive sensing of the fingerprint recognition sensor. In this embodiment, the size of the high dielectric particles is greater than or equal to 0.05 micrometer (μm) and less than or equal to 5 μm. The high dielectric particles may be titanate particles or niobate particles. The titanate particles may specifically be: barium titanate (BaTiO ₃ ), calcium titanate (CaTiO _{3 ), strontium titanate (SrCaTiO 3 )} , and the like.

For the niobate particles, specifically, it may be: sodium barium niobate (Ba ₂ NaNb ₅ O ₁₅ ), potassium strontium niobate (KSr ₂ Nb ₅ O ₁₅ ), potassium tantalum niobate (KTaNbO ₃ ), and the like.

In this embodiment, in addition to titanate particles or niobate particles, cadmium pyroniobate (Cd ₂ Nb ₂ O ₇ ) particles and tungsten trioxide (WO ₃ ) may also be used. As for the specific high dielectric particles, this embodiment will not repeat them here, as long as the dielectric constant at 1 GHz is greater than 10.

The finally obtained color film doped with high dielectric particles can have a dielectric constant of more than 4 at 1 GHz after curing.

The finally obtained hard mask layer doped with high dielectric particles can have a dielectric constant above 4 at 1 GHz after curing.

The principle of the capacitive sensing of the user's fingerprint by the fingerprint identification sensor will be specifically described below with reference to FIG. 2 and FIG. 3 in a specific embodiment. The fingerprint identification sensor in this embodiment may be a sweep type (sweep or swipe), or a push type (touch or area), which is not particularly limited in this embodiment.

FIG. 2 is a schematic diagram of a fingerprint recognition scene according to the present invention. As shown in Figure 2, a human finger includes crests and valleys. When the finger is pressed along the hard mask layer close to the fingerprint recognition sensor, the fingerprint recognition sensor presents a capacitive connection mode. When the person puts the finger on the fingerprint When above the recognition sensor, the finger acts as another electrode of the fingerprint recognition sensor. Due to the existence of crests and troughs on the finger with different depths, the voltages of the capacitors in the capacitor array included in the fingerprint recognition sensor are different. The peak of the fingerprint of the user's finger 1 is 11, and when the hard mask layer is pressed, the fingerprint identification sensor senses and presents the peak 11a of the fingerprint.

Fig. 3 is a schematic diagram of the fingerprint recognition principle of the present invention. A capacitive fingerprint recognition sensor includes a plurality of capacitive sensor units. As shown in FIG. 3 , three capacitive sensor units 20 are shown in FIG. 3 . The capacitive sensor unit 20 includes a reference capacitor 325 and sensing electrodes 31 and 32 . Please continue to refer to Figure 2, the crest of the fingerprint of the user's finger 1 is 11, when the hard mask layer is pressed, the capacitance between the crest 11 and the sensing electrode 31 on the fingerprint recognition sensor is 324, and the valley 12 is connected to the fingerprint The capacitance between the sensing electrodes 31 on the identification sensor is 324'. It can be seen from Fig. 3 that the distances between the crests and troughs and the sensing electrodes 31 on the fingerprint recognition sensor are different, resulting in different capacitance values. A logic circuit is integrated on the silicon chip, and the logic circuit passes corresponding The algorithm generates fingerprint images, and then realizes fingerprint identification.

Those skilled in the art can understand that the above embodiment only schematically shows a method for identifying fingerprints through capacitance. In the actual implementation process, there are many ways to identify fingerprints through capacitance, but the principles are roughly the same. Utilizing the different capacitances corresponding to the "ridges" and "valleys" contained in the fingerprint, the different capacitance values are processed, and then the fingerprint image is generated. For other methods of identifying fingerprints through capacitance, details will not be described here in this embodiment.

Those skilled in the art can understand that capacitance C=εS/d (ε is the dielectric constant of the medium between the finger and the sensing electrode, S is the area of the plate, and d is the distance between the finger and the sensing electrode). In this embodiment, the medium between the human finger and the sensing electrode includes two kinds, one is air, and the other is the color film layer and hard mask layer arranged above the fingerprint recognition sensor. Since the hard mask layer in this embodiment In the film layer or the color film layer, at least one layer is doped with high dielectric particles, then the dielectric constant of the hard mask layer or the color film layer increases, thereby increasing the capacitor between the finger and the sensing electrode (324' and 324 corresponding ) capacitance, so that the sensing of the capacitance by the fingerprint recognition sensor is more obvious, which can improve the recognition accuracy of the capacitive fingerprint recognition sensor. Further, in the case of constant capacitance, if the dielectric constant increases, the distance d will be increase, that is, this embodiment can also increase the recognition distance of the fingerprint recognition sensor.

Those skilled in the art can understand that FIG. 2 and FIG. 3 mainly illustrate the principle of press-type fingerprint recognition in which a finger is still in contact with the hard mask layer. For the swipe type, when performing fingerprint recognition, the user can slide the finger on the hard mask layer. When the finger slides over the hard mask layer, the fingerprint recognition sensor can collect multiple fingerprint images, and through the detection of finger The initial position of the finger, the speed and direction of the finger sliding to reconstruct the entire fingerprint image, and finally form the fingerprint image of the entire finger. When the fingerprint recognition sensor collects each fingerprint image, its collection method is similar to the embodiment in FIG. 3 . Therefore, this embodiment can also increase the recognition accuracy of the swiping fingerprint recognition sensor.

The packaging structure of the fingerprint recognition sensor provided in this embodiment includes: a fingerprint recognition sensor disposed above the silicon wafer and electrically connected to the silicon wafer; a color film layer disposed above the fingerprint recognition sensor; a color film layer disposed above the color film layer Hard mask layer; the substrate arranged under the silicon wafer, wherein, in the hard mask layer or the color film layer, at least one layer is doped with high dielectric particles, so as not only to make the sensing of the capacitance by the fingerprint recognition sensor more obvious , can improve the recognition accuracy of the fingerprint recognition sensor, and can also increase the recognition distance of the fingerprint recognition sensor.

Optionally, when the distance between the fingerprint recognition sensor and the finger is relatively long, the ability of the fingerprint recognition sensor to perceive fingerprints is relatively weak. In order to ensure that the fingerprint recognition sensor in the fingerprint recognition sensor packaging The thickness of the film layer and the thickness of the color film layer are controlled. In this embodiment, the sum of the thickness of the hard mask layer and the thickness of the color film layer is less than or equal to 100 μm.

In the specific implementation process, it can be divided into the following possible implementation methods. One possible implementation method is: the thickness of the hard mask layer is greater than or equal to 10 μm and less than or equal to 50 μm, the hard mask layer and the color film layer The sum of the thicknesses is less than 100 μm.

In another possible implementation manner, the thickness of the color film layer is greater than or equal to 5 μm and less than or equal to 50 μm, and the sum of the thicknesses of the hard mask layer and the color film layer is less than 100 μm.

In yet another possible implementation, the thickness of the hard mask layer is greater than or equal to 10 μm and less than or equal to 50 μm, and the thickness of the color film layer is greater than or equal to 5 μm and less than or equal to 50 μm.

Further, in order to make the packaging structure of the fingerprint recognition sensor applicable in various occasions, the thickness of the two can be made as thin as possible, so as to reduce the thickness of the fingerprint recognition sensor in the vertical direction. At this time, the sum of the thickness of the hard mask layer and the thickness of the color film layer is less than or equal to 50 μm.

In the specific implementation process, it can be divided into the following possible implementation methods. One possible implementation method is: the thickness of the hard mask layer is greater than or equal to 10 μm and less than or equal to 30 μm, and the thickness of the hard mask layer and the color film layer and less than 50μm.

In another possible implementation manner, the thickness of the color film layer is greater than or equal to 10 μm and less than or equal to 30 μm, and the sum of the thicknesses of the hard mask layer and the color film layer is less than 30 μm.

In yet another possible implementation, the thickness of the hard mask layer is greater than or equal to 10 μm and less than or equal to 30 μm, and the thickness of the color film layer is greater than or equal to 10 μm and less than or equal to 30 μm.

The raw materials and preparation methods of the hard mask layer and the color film layer will be described in detail below using specific examples.

Color film

1) If the color film layer is doped with high dielectric particles, the color film layer is made of the following components by weight ratio through a thermal curing process:

High dielectric particles: 5-30 parts, color materials: 30-80 parts, polymer resin: 20-50 parts, solvent: 0.1-10 parts, dispersant: 0.1-5 parts, the sum of the above components is 100 copies;

Wherein, the polymer resin includes at least one of the following:

Phenolic resin, epoxy resin, polycarbonate, acrylic resin, epoxy resin, polyurethane resin or silicone resin, etc. In this embodiment, there is no special requirement on the hardness of the polymer resin, and any polymer resin that can be brushed and cured by heat can be applied to this embodiment.

The solvent is composed of at least one of the following: the solvent is ethanol, n-butanol, isobutanol, ethylene glycol-butyl ether, butyl acetate, cyclohexanone, glycidyl ether, tetrahydrofuran, methyl ethyl ketone, cyclic Hexanone, propylene glycol, N,N-dimethylformamide, ethylene glycol ether acetate, ethyl acetate, etc.; this example only lists some solvents, and all solvents that can dissolve polymer resins are listed in this Within the protection scope of the invention embodiment.

The dispersant is composed of at least one of the following: polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, polyvinyl alcohol, etc.; the present embodiment only lists some dispersants, and any dispersant that can be dispersed in the above solvents has a high Dispersants for dielectric particles are all within the protection scope of the embodiments of the present invention.

The color material can be nano- or micron-sized particles, such as titanium dioxide, carbon black, etc., or a colored organic liquid.

In the specific implementation process, the polymer resin, high dielectric particles and color materials are dissolved in a solvent, and a dispersant is added to the solvent. The function of the dispersant is mainly to make the high dielectric particles and color materials uniformly dispersed in the In a solvent containing a polymer resin.

After the high-dielectric particles and color materials are evenly dispersed in the solvent with polymer resin, the solvent can be brushed on the fingerprint recognition sensor, and then heat-cured, wherein the heat-curing temperature is 100°C-180°C , the curing time is related to the curing temperature, the curing time is 10min-90min, after thermal curing, the solid content is 50%-90%, the shrinkage ratio before and after curing is less than 5%, and the thickness of the color film obtained after curing is between 10μm to Between 30μm.

2) If the color film layer is doped with high dielectric particles, the color film layer is made of the following components by UV curing process in weight ratio:

Doped high dielectric particles: 5-30 parts, color material: 30-80 parts, organic monomer: 20-50 parts, diluent: 0.1-10 parts, photoinitiator: 0.1-5 parts, stabilizer: 0.1 -5 parts, the sum of the above-mentioned components is 100 parts;

Wherein, the organic monomer includes at least one (meth)acrylate monomer as follows:

Hydroxypropyl (meth)acrylate, Hydroxyethyl (meth)acrylate, Hydroxybutyl (meth)acrylate, Isobornyl (meth)acrylate, Tetrahydrofuryl (meth)acrylate, Ethoxy(methyl)acrylate ) acrylate, lauryl (meth)acrylate, decayl (meth)acrylate, tridecyl (meth)acrylate

The color material can be nano- or micron-sized particles, such as titanium dioxide, carbon black, etc., or a colored organic liquid.

The diluent consists of at least one of the following: tripropylene glycol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, polydipentaerythritol hexaacrylate, 1,6- Hexylene glycol methoxy monoacrylate, ethoxylated neopentyl glycol methoxy monoacrylate, etc., the diluent in this embodiment plays a diluting role on the one hand, so that the solution of the color film is biased towards brushing; On the other hand, it also acts as a cross-link. This embodiment only lists some diluents, and other diluents will not be repeated here in this embodiment.

The photoinitiator is composed of at least one of the following: aromatic diazonium salt, aromatic sulfonium salt, aromatic iodonium salt or ferrocene salt, polyvinyl alcohol cinnamate, polyethylene cinnamylidene malonate polyethylene glycol Esters, etc.; the role of the photoinitiator is to generate free radicals or ions through decomposition after the colloid absorbs ultraviolet light energy, and then triggers the polymerization and crosslinking of organic monomers to form a network structure. This embodiment only lists some photoinitiators, and other photoinitiators will not be repeated here in this embodiment.

The stabilizer is composed of at least one of the following: hydroquinone, p-methoxyphenol, p-benzoquinone, 2,6-di-tert-butylcresol, phenothiazine, anthraquinone and the like. The stabilizer is used to reduce the further polymerization of the polymerization product during storage and improve the storage stability.

In the specific implementation process, the diluted solvent can be brushed on the fingerprint recognition sensor, and then cured by ultraviolet light. The wavelength of ultraviolet light is less than 400nm, and the curing time is 10s to 60s. %-90%, the shrinkage ratio before and after curing is less than 2%, and the thickness of the color film layer obtained after curing is between 10 μm and 30 μm.

hard mask layer

When the hard mask layer is doped with high dielectric particles, the hard mask layer in this embodiment can be realized by thermal curing or ultraviolet light curing process, which will be described respectively below.

1) If the hard mask layer is doped with high dielectric particles, the hard mask layer is made of the following components by weight ratio through a thermal curing process:

High dielectric particles: 10-60 parts, polymer resin: 50-80 parts, solvent: 0.1-10 parts, dispersant: 0.1-5 parts, the sum of the above components is 100 parts.

Wherein, the polymer resin comprises at least one of the following:

Phenolic, epoxy, polycarbonate, acrylic or polyurethane resins.

The resins listed above all have relatively high hardness and mechanical strength, which can ensure the hardness of the hard mask layer. Those skilled in the art can understand that the above is only a schematic list of possible implementations of the polymer resin, and in a specific implementation process, any polymer resin with high hardness can be applied to this embodiment.

The solvent consists of at least one of the following: ethanol, n-butanol, isobutanol, ethylene glycol-butyl ether, butyl acetate, cyclohexanone, glycidyl ether, tetrahydrofuran, methyl ethyl ketone, cyclohexanone , propylene glycol, N,N-dimethylformamide, ethylene glycol ethyl ether acetate, ethyl acetate, etc.; this embodiment only lists some solvents, and all solvents that can dissolve polymer resins are implemented in the present invention within the protection scope of the example.

The dispersing agent is composed of at least one of the following: polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, polyvinyl alcohol, etc.; this embodiment only lists some dispersing agents, and those who can disperse high dielectric strength in the above solvents The dispersant of the particles is within the protection scope of the embodiments of the present invention.

In the specific implementation process, the polymer resin and high dielectric particles are dissolved in a solvent, and a dispersant is added to the solvent. The function of the dispersant is mainly to make the high dielectric particles uniformly dispersed in the polymer resin dissolved. in solvent.

After the high-dielectric particles are uniformly dispersed in the solvent with polymer resin, the solvent can be sprayed on the color film layer, and then thermally cured. The thermal curing temperature is 100°C-180°C, and the curing time is the same as The curing temperature is related, the curing time is 10min-90min, after thermal curing, the solid content is 50%-90%, the shrinkage ratio before and after curing is less than 5%, and the thickness of the hard mask layer obtained after curing is between 10μm and 30μm .

2) If the hard mask layer is doped with high dielectric particles, the hard mask layer is made of the following components by weight ratio through UV curing process:

High dielectric particles: 10-60 parts, organic monomer: 50-80 parts, diluent: 0.1-10 parts, photoinitiator: 0.1-5 parts, stabilizer: 0.1-5 parts, one of the above-mentioned components and for 100 copies;

Wherein, the organic monomer includes at least one (meth)acrylate monomer as follows:

Hydroxypropyl (meth)acrylate, Hydroxyethyl (meth)acrylate, Hydroxybutyl (meth)acrylate, Isobornyl (meth)acrylate, Tetrahydrofuryl (meth)acrylate, Ethoxy(methyl)acrylate ) acrylate, lauryl (meth)acrylate, decayl (meth)acrylate, tridecyl (meth)acrylate.

The organic monomers listed above can be cured and cross-linked to obtain methacrylic polymers with higher hardness. Those skilled in the art can understand that the above is only a schematic list of possible implementations of organic monomers. In the specific implementation process, all organic monomers that can obtain high polymers after crosslinking can be applied to this implementation. example.

The diluent consists of at least one of the following: tripropylene glycol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, polydipentaerythritol hexaacrylate, 1,6- Hexylene glycol methoxy monoacrylate, ethoxylated neopentyl glycol methoxy monoacrylate, etc.; on the one hand, the diluent in this embodiment acts as a diluent, so that the liquid of the hard mask layer is biased towards spraying; On the other hand, it also acts as a cross-link. This embodiment only lists some diluents, and other diluents will not be repeated here in this embodiment.

The photoinitiator is composed of at least one of the following: aromatic diazonium salt, aromatic sulfonium salt, aromatic iodonium salt or ferrocene salt, polyvinyl alcohol cinnamate, polyethylene cinnamylidene malonate polyethylene glycol Esters, etc.; the role of the photoinitiator is to generate free radicals or ions through decomposition after the colloid absorbs ultraviolet light energy, and then triggers the polymerization and crosslinking of organic monomers to form a network structure. This embodiment only lists some photoinitiators, and other photoinitiators will not be repeated here in this embodiment.

The stabilizer is composed of at least one of the following: hydroquinone, p-methoxyphenol, p-benzoquinone, 2,6-di-tert-butylcresol, phenothiazine, anthraquinone and the like. The stabilizer is used to reduce the further polymerization of the polymerization product during storage and improve the storage stability.

In the specific implementation process, the diluted solvent can be sprayed on the color film layer, and then cured by ultraviolet light. The wavelength of ultraviolet light is less than 400nm, and the curing time is 10s to 60s. After ultraviolet light curing, the solid content is 50%. -90%, the shrinkage ratio before and after curing is less than 2%, and the thickness of the hard mask layer obtained after curing is between 10 μm and 20 μm.

Those skilled in the art can understand that the embodiment in FIG. 1 only schematically shows the packaging structure of the fingerprint identification sensor. In a specific implementation process, further improvements can be made on the basis of the packaging structure of the fingerprint identification sensor. Several specific examples are taken below for illustration.

FIG. 4 is a second schematic cross-sectional view of the packaging structure of the fingerprint recognition sensor of the present invention. The package structure of the fingerprint identification sensor provided in this embodiment includes: a fingerprint identification sensor 403 arranged above the silicon wafer 402 and electrically connected to the silicon wafer; a color film layer 404 provided above the fingerprint identification sensor 403; a hard mask layer 405 disposed above; a substrate 401 disposed below a silicon wafer 402 .

The substrate 401 is electrically connected to the fingerprint recognition sensor 403 through the solder ball 406, and since the fingerprint recognition sensor 403 is electrically connected to the silicon wafer 402, it means that the substrate 401 can be electrically connected to the silicon wafer 402 through the solder ball 406 and the fingerprint recognition sensor 403, that is, this In the embodiment, the silicon wafer 402 is not directly electrically connected to the substrate 401 , but is indirectly electrically connected to the silicon wafer 402 through the solder balls 406 and the fingerprint recognition sensor 403 . The main material of the solder ball 406 in this embodiment includes tin, lead, silver, copper and the like.

The substrate 401 may be a Flexible Printed Circuit (FPC for short) or a Printed Circuit Board (PCB for short), or an FPC and a PCB arranged from bottom to top. Specifically, the PCB and the FPC can be connected through solder paste.

Optionally, the length of the silicon wafer 402 is shorter than the length of the fingerprint recognition sensor 403 . Since the length of the silicon wafer 402 is smaller, the cost of the silicon wafer 402 is saved.

Optionally, wires are provided on the silicon wafer 402 in this embodiment, and the silicon wafer 402 is electrically connected to the fingerprint identification sensor 403 through the wires. Specifically, the wires may be solder. In addition, an adhesive is provided between the silicon wafer 402 and the fingerprint identification sensor 403, and the adhesive is used for bonding the silicon wafer 402 and the fingerprint identification sensor 403, and plays a role of filling. Specifically, the adhesive may be epoxy resin (Epoxy), which can effectively improve the mechanical strength of the wire (not shown).

Optionally, an epoxy molding compound (EMC for short) layer 407 is also filled between the silicon wafer 402 and the substrate 401. The EMC layer 407 not only plays a filling role, but also can compensate for the gap between the silicon wafer 402 and the substrate 401. The difference in thermal expansion coefficient between them prevents moisture damage and protects the silicon wafer 402.

FIG. 5 is a schematic cross-sectional view III of the packaging structure of the fingerprint identification sensor of the present invention. The embodiment in FIG. 5 is implemented on the basis of the embodiment in FIG. 4 . Specifically, this embodiment is based on the embodiment in FIG. 4 , and the package structure of the fingerprint recognition sensor further includes an outer frame (Bezel) 408, and the outer frame 408 is arranged on both sides of the silicon wafer 402 and the fingerprint recognition sensor 403, specifically , the bottom of the outer frame 408 may contact the substrate 401 . The outer frame 408 can not only play a role of decoration and protection, but also make the user feel better. The material of the outer frame 408 can be metal or plastic.

The outer frame 408 can have multiple deformations. The height of the outer frame 408 is the same as the height of the hard mask layer 405. It is also possible that the height of the outer frame 408 is higher than the upper surface (not shown) of the hard mask layer 405. In addition , the outer frame 408 can also be in an inclined form as shown in FIG. , or as shown in FIG. 7 , the inclined side of the outer frame 408 forms an obtuse angle with the upper surface of the hard mask layer 405 , and the inclined side of the outer frame 408 is in contact with the upper surface of the hard mask layer 405 .

4 to 7, the preparation process is as follows: first electrically connect the fingerprint recognition sensor 403 to the silicon wafer 402, then connect the silicon wafer 402 to the substrate 401 through solder balls 406, and then set a mold on the substrate 401 , the mold surrounds the fingerprint recognition sensor 403, and EMC is poured into the mold to form a filling layer on the substrate 401 that wraps the fingerprint recognition sensor 403 and does not cover the upper surface of the fingerprint recognition sensor 403, and then removes the mold. Next, a color film layer 404 and a hard mask layer 405 are sequentially prepared on the surface of the current structure, and finally a frame 408 (Bezel) is placed on the edge of the whole module.

For the packaging structures shown in FIGS. 4 to 7 , the packaging process is relatively complicated. In the specific implementation process, the form of overall packaging can also be adopted, that is, the fingerprint recognition sensor is electrically connected to the silicon chip, and then the silicon chip is connected to the substrate through solder balls, and then the color film layer and the The hard mask layer is finally subjected to injection molding packaging, and the obtained packaging structure can be specifically shown in FIG. 8 to FIG. 11 .

FIG. 8 is a schematic cross-sectional view VI of the packaging structure of the fingerprint identification sensor of the present invention. As shown in FIG. 8 , the packaging structure of the fingerprint recognition sensor provided by this embodiment includes: a fingerprint recognition sensor 403 arranged above the silicon wafer 402 and electrically connected to the silicon wafer; a color film layer 404 arranged above the fingerprint recognition sensor 403 ; the hard mask layer 405 disposed above the color film layer 404 ; the substrate 401 disposed below the silicon wafer 402 . Those skilled in the art can understand that the above package structure is an overall package. Then, an outer frame 408 is provided on both sides of the silicon wafer 402 and the fingerprint identification sensor 403 . In this embodiment, when the outer frame 408 is set, it is in a semi-closed mode, that is, the outer frame 408 is not overlapped on the hard mask layer 405 . At this time, the structure composed of the outer frame 408 and the substrate 401 is equivalent to a mold. At this time, during injection molding and packaging, EMC can be poured into the mold through the non-overlapping opening to form a fingerprint recognition sensor 403, color film layer 404, and hard mask layer 405 on the substrate 401 without covering the hard mask layer. A filling layer on the upper surface of the mask layer 405 .

In this embodiment, the substrate 401 is electrically connected to the fingerprint recognition sensor 403 through the solder ball 406, and since the fingerprint recognition sensor 403 is electrically connected to the silicon wafer 402, it means that the substrate 401 can be connected to the silicon wafer through the solder ball 406 and the fingerprint recognition sensor 403. 402 is electrically connected, that is, in this embodiment, the silicon wafer 402 is not directly electrically connected to the substrate 401 , but is indirectly electrically connected to the silicon wafer 402 through the solder ball 406 and the fingerprint recognition sensor 403 . The main material of the solder ball 406 in this embodiment includes tin, lead, silver, copper and the like.

The substrate 401 may be a Flexible Printed Circuit (FPC for short) or a Printed Circuit Board (PCB for short), or an FPC and a PCB arranged from bottom to top. Specifically, the PCB and the FPC can be connected through solder paste.

Optionally, the length of the silicon wafer 402 is shorter than the length of the fingerprint recognition sensor 403 . Since the length of the silicon wafer 402 is smaller, the cost of the silicon wafer 402 is saved.

Optionally, wires are provided on the silicon wafer 402 in this embodiment, and the silicon wafer 402 is electrically connected to the fingerprint identification sensor 403 through the wires. Specifically, the wires may be solder. In addition, an adhesive is provided between the silicon wafer 402 and the fingerprint identification sensor 403, and the adhesive is used for bonding the silicon wafer 402 and the fingerprint identification sensor 403, and plays a role of filling. Specifically, the adhesive may be epoxy resin (Epoxy), which can effectively improve the mechanical strength of the wire (not shown).

FIG. 9 is a schematic cross-sectional view VII of the packaging structure of the fingerprint recognition sensor of the present invention. The overall package structure of this embodiment is similar to that of the embodiment shown in FIG. 8 , and details will not be repeated here in this embodiment. The difference between this embodiment and the embodiment shown in FIG. 8 is that when the outer frame 408 is provided in this embodiment, it is a closed structure. The outer frame 408 is just overlapped on the hard mask layer 405, and the side wall of the outer frame 408 is equipped with a perfusion hole 409, through which the EMC can be poured into the mold composed of the outer frame 408 and the substrate 401, so as to realize the final encapsulation.

FIG. 10 is a schematic cross-sectional view eight of the packaging structure of the fingerprint recognition sensor of the present invention. The overall package structure of this embodiment is similar to that of the embodiment shown in FIG. 8 , and details will not be repeated here in this embodiment. The difference between this embodiment and the embodiment shown in FIG. 8 is that when the outer frame 408 is provided in this embodiment, it is a closed structure. The outer frame 408 is partially overlapped on the hard mask layer 405, and the side wall of the outer frame 408 is equipped with a perfusion hole 409, through which the EMC can be poured into the mold composed of the outer frame 408 and the substrate 401, so as to realize the final encapsulation.

FIG. 11 is a schematic cross-sectional view of the package structure of the fingerprint identification sensor IX according to the present invention. The overall package structure of this embodiment is similar to that of the embodiment shown in FIG. 8 , and details will not be repeated here in this embodiment. The difference between this embodiment and the embodiment shown in FIG. 8 is that when the outer frame 408 is provided in this embodiment, it is a closed structure. The outer frame 408 is just overlapped on the hard mask layer 405, and the side wall of the outer frame 408 is provided with a perfusion hole 409, through which the EMC can be poured into the mold composed of the outer frame 408 and the substrate 401, and the mold is formed outside the mold. A fill layer 410 is implemented to achieve the final encapsulation.

The packaging structure of the fingerprint recognition sensor provided in this embodiment can use the frame to pour the plastic sealing material to form a filling layer. The filling layer can be formed without setting a mold, and there is no need to remove the mold later, which effectively simplifies the preparation process of the fingerprint recognition module. processes to improve production efficiency. Moreover, the protruding portion of the frame can more effectively fix the filling layer and its internal packaging structure, improving device reliability.

FIG. 12 is a schematic flowchart of Embodiment 1 of the method for packaging a fingerprint identification sensor of the present invention. As shown in Figure 12, the method provided in this embodiment includes:

Step 1201, setting a fingerprint identification sensor above the silicon wafer, and electrically connecting the fingerprint identification sensor to the silicon wafer;

Step 1202, setting a color film layer above the fingerprint identification sensor;

Step 1203, setting a hard mask layer above the color film layer, at least one of the hard mask layer and the color film layer is doped with high dielectric particles;

Step 1204, disposing the silicon wafer on the substrate.

In step 1201, on the side of the silicon wafer without circuits, the silicon wafer is flip-chipped on the fabricated fingerprint recognition sensor by wire bonding and flip-chip silicon wafer, that is, the fingerprint recognition sensor is set above the silicon wafer , the silicon chip and the fingerprint recognition sensor are connected by wires. Further, an adhesive can also be filled between the silicon wafer and the fingerprint recognition sensor, so that the silicon wafer and the fingerprint recognition sensor can be firmly connected.

In step 1202, a color film is sprayed or silk-screened on the fingerprint recognition sensor. Those skilled in the art can understand that the spraying or silk-screening methods are slightly different depending on the color of the color film.

When the color film layer is dark, the color film layer can be directly above the fingerprint recognition sensor, and then heat-cured or light-cured. After the curing is completed, if the effect of the color film layer is not enough, the process of brushing and curing can be continued , until the color effect of the color film layer meets the requirements.

When the color film is light-colored, you can apply a dark-colored film on the top of the fingerprint recognition sensor as a base color, and then apply a light-colored film after the dark-colored film is cured.

In step 1203, a hard mask layer is sprayed on the color film layer, and then formed by photocuring or ultraviolet curing.

In step 1204, a silicon wafer is disposed on a substrate.

In the packaging method provided by this embodiment, a fingerprint recognition sensor is arranged above the silicon wafer, and the fingerprint recognition sensor is electrically connected to the silicon wafer; a color film layer is provided above the fingerprint recognition sensor; a hard mask layer is provided above the color film layer, At least one layer of the hard mask layer and the color film layer is doped with high-dielectric particles; the silicon wafer is placed on the substrate, and the fingerprint recognition sensor packaging structure is prepared, which not only makes the sensing of the capacitance by the fingerprint recognition sensor more obvious, but also can Improving the recognition accuracy of the fingerprint recognition sensor can also increase the recognition distance of the fingerprint recognition sensor.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (12)

1. A fingerprint identification sensor package structure, comprising:

a fingerprint recognition sensor disposed above and electrically connected to the silicon wafer;

a color film layer disposed over the fingerprint identification sensor;

a hard mask layer arranged above the color film layer;

a substrate disposed below the silicon wafer;

at least one layer of the hard mask layer and the color film layer is doped with high dielectric particles;

if the hard mask layer is doped with high-dielectric particles, the hard mask layer is prepared from the following components in parts by weight through a thermal curing process: high dielectric particles: 10-60 parts of polymer resin: 50-80 parts of solvent: 0.1-10 parts of dispersant: 0.1-5 parts, wherein the sum of the components is 100 parts; wherein the polymer resin comprises at least one of: phenolic, epoxy, polycarbonate, acrylic or polyurethane resins; or,

the hard mask layer is prepared from the following components in parts by weight through an ultraviolet curing process: high dielectric particles: 10-60 parts of organic monomer: 50-80 parts of diluent: 0.1-10 parts of photoinitiator: 0.1-5 parts of stabilizer: 0.1-5 parts, wherein the sum of the components is 100 parts; wherein the organic monomer comprises at least one (meth) acrylate monomer of: hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, ethoxy (meth) acrylate, dodecyl (meth) acrylate, decyl (meth) acrylate, tridecyl (meth) acrylate.

2. The package structure of claim 1, wherein a sum of a thickness of the hard mask layer and a thickness of the color film layer is less than or equal to 100 μm.

3. The package structure of claim 2, wherein the thickness of the hard mask layer is greater than or equal to 10 μ ι η and less than or equal to 50 μ ι η.

4. The package structure of claim 2, wherein the thickness of the color film layer is greater than or equal to 5 μ ι η and less than or equal to 50 μ ι η.

5. The package structure of claim 2, wherein a sum of a thickness of the hard mask layer and a thickness of the color film layer is less than or equal to 50 μm.

6. The package structure of claim 5, wherein the thickness of the hard mask layer is greater than or equal to 10 μm and less than or equal to 30 μm.

7. The package structure of claim 5, wherein the thickness of the color film layer is greater than or equal to 10 μm and less than or equal to 30 μm.

8. The encapsulation structure according to any one of claims 1 to 7, wherein the high dielectric particles comprise any one or a combination of:

titanate particles;

niobate particles.

9. The package structure of claim 8, wherein the high dielectric particles have a size greater than or equal to 0.05 μ ι η and less than or equal to 5 μ ι η.

10. The package structure according to claim 9, wherein if the color film is doped with high dielectric particles, the color film is prepared by a thermal curing process from the following components in parts by weight:

high dielectric particles: 5-30 parts of color material: 30-80 parts of high molecular resin: 20-50 parts of solvent: 0.1-10 parts of dispersant: 0.1-5 parts, wherein the sum of the components is 100 parts;

wherein the polymer resin comprises at least one of the following:

phenolic, epoxy, polycarbonate, acrylic, epoxy, polyurethane or silicone resins.

11. The package structure according to claim 9, wherein if the color film is doped with high dielectric particles, the color film is prepared by an ultraviolet curing process from the following components in parts by weight:

doping high dielectric particles: 5-30 parts of color material: 30-80 parts of organic monomer: 20-50 parts of diluent: 0.1-10 parts of photoinitiator: 0.1-5 parts of stabilizer: 0.1-5 parts, wherein the sum of the components is 100 parts;

wherein the organic monomer comprises at least one (meth) acrylate monomer of:

hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, ethoxy (meth) acrylate, dodecyl (meth) acrylate, decyl (meth) acrylate, tridecyl (meth) acrylate.

12. A fingerprint sensor packaging method, comprising:

arranging a fingerprint identification sensor above a silicon wafer, wherein the fingerprint identification sensor is electrically connected with the silicon wafer;

arranging a color film layer above the fingerprint identification sensor;

arranging a hard mask layer above the color film layer, wherein at least one layer of the hard mask layer and the color film layer is doped with high-dielectric particles;

disposing the silicon wafer on a substrate;

if the hard mask layer is doped with high-dielectric particles, the hard mask layer is prepared from the following components in parts by weight through a thermal curing process: high dielectric particles: 10-60 parts of polymer resin: 50-80 parts of solvent: 0.1-10 parts of dispersant: 0.1-5 parts, wherein the sum of the components is 100 parts; wherein the polymer resin comprises at least one of: phenolic, epoxy, polycarbonate, acrylic or polyurethane resins; or,

the hard mask layer is prepared from the following components in parts by weight through an ultraviolet curing process: high dielectric particles: 10-60 parts of organic monomer: 50-80 parts of diluent: 0.1-10 parts of photoinitiator: 0.1-5 parts of stabilizer: 0.1-5 parts, wherein the sum of the components is 100 parts; wherein the organic monomer comprises at least one (meth) acrylate monomer of: hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, ethoxy (meth) acrylate, dodecyl (meth) acrylate, decyl (meth) acrylate, tridecyl (meth) acrylate.