WO2022065881A1 - Ultrasonic sensor for establishing three-dimensional fingerprint information - Google Patents

Abstract

The present invention provides an ultrasonic sensor comprising: a sensor die including a sensing unit in which a plurality of nano-rods having a piezoelectric effect are arrayed to sense a user's fingerprint, a first electrode that is in electrical contact with the nano-rods along a line of the nano-rods in a first axial direction so as to form one surface of the sensing unit, a second electrode that is in electrical contact with the nano-rods along a line of the nano-rods in a second axial direction so as to form the other surface of the sensing unit, a first flip-chip electrode that is in electrical contact with one end of the first electrode so as to integrally distribute an electrical signal to the nano-rods located in the line in the first axial direction, and a second flip-chip electrode that is in electrical contact with one end of the second electrode so as to integrally distribute an electrical signal to the nano-rods located in the line in the second axial direction; and an ultrasonic sensor substrate having solder balls formed at one end or the other end of the first axis in the line in the first axial direction of the arrayed nano-rods so as to be in contact with the first flip-chip electrode and solder balls formed at one end or the other end of the second axis in the line in the second axial direction of the nano-rods so as to be in contact with the second flip-chip electrode, wherein the solder balls bonded to the sensor die is provided in a number equal to or less than half of the number of the arrayed nano-rods, wherein the sensor die is flip-chip bonded to the ultrasonic sensor substrate.

Description

Ultrasonic sensor that builds 3D fingerprint information

The present invention relates to an ultrasonic sensor, and more particularly, to an ultrasonic sensor that can be manufactured by packaging by flip-chip bonding and can construct three-dimensional fingerprint information.

Fingerprint recognition is one of the most effective and popular ways to identify yourself. There are several methods of recognizing a fingerprint, and most fingerprint authentication methods including smartphones up to now employ the electrostatic method. The capacitive capacitive method is the most common fingerprint recognition method, but there is a drawback that a fingerprint can be copied and used, so the need for a fingerprint method with enhanced security is increasing. Accordingly, a fingerprint recognition method that has recently received attention is a fingerprint recognition method using ultrasonic waves.

For ultrasonic fingerprint recognition, a sensor must be constructed using a material called lead zirconate titanate (PZT). PZT materials are commonly known as piezoelectric materials. A piezoelectric material is a material in which mechanical force is converted into an electrical signal or, conversely, a mechanical change is generated by an electrical signal. The method of emitting ultrasonic waves using PZT material and detecting fingerprints with reflected and returned ultrasonic information is collectively called the ultrasonic fingerprint method.

However, up to now, a three-dimensional fingerprint method using ultrasound has not been commercialized. For reasons of difficulty in commercialization, first, it is pointed out that in order to implement a three-dimensional fingerprint method with ultrasound, a large number of PZT ultrasonic sensors must be precisely implemented with fine nanorods corresponding to the valleys of the fingerprint.

Second, even if the nanorods are precisely implemented, wire bonding must be performed in the process of packaging each of the microscopic nanorods on the PCB substrate. Since the electrical bonding process of wiring is difficult for each of the microscopic nanorods, an ultrasonic sensor must be implemented to enable the flip-chip method in the end.

The ultrasonic sensor is implemented as an ultrasonic sensor through the packaging process of mounting the die provided with the sensor element for sensing on the PCB board. In the process of mounting the PCB board, the PCB board and the sensor element must be electrically connected. Methods of electrical connection in such a packaging process include a wire bonding method and a flip chip bonding method.

Flip-chip bonding refers to a method of bonding a semiconductor chip to a circuit board without using an additional connection structure such as a metal lead wire or an intermediate medium such as a ball grid array (BGA), but using an electrode pattern on the bottom of the chip as it is. It is also called a leadless semiconductor, and since the package is the same size as the chip, it is advantageous for miniaturization and weight reduction, and it is a bonding method that can reduce the distance between electrodes.

Conventional ultrasonic sensors do not provide a die structure to which a flip chip method can be applied. Conventionally, when implementing an ultrasonic sensor, a mesh structure or a plate-shaped PZT sensor is configured instead of a nanorod structure. Accordingly, the conventional ultrasonic sensor performs a fingerprint recognition process similar to that of the capacitive type using the capacitive response of the ultrasonic wave. As a result, the conventional ultrasonic sensor cannot directly measure the height information of a fingerprint even using the ultrasonic principle, so two-dimensional fingerprint mapping has to be performed.

The conventional ultrasonic fingerprint sensor is manufactured using a micro-mechanical (MEMS) process. In this case, it is necessary to proceed with a process with a height difference of 100 μm or more. However, there is a disadvantage that a step difference of 100 μm or more cannot be overcome with the general thin film process, so a new process must be applied. In this regard, the present applicant has proposed a method of manufacturing an ultrasonic sensor of a new process, and the related applicant's prior patent (Korean Patent No. 10-2070851) will be described later.

The technical reason that the studied 3D ultrasonic sensor has difficulties in commercialization can be summarized as a sensor die capable of flip-chip bonding must be presented and the packaging technology of the manufactured sensor die must be supported.

The current technology trend with the background that the 3D ultrasonic sensor has not yet been introduced is as follows. In 2019, an error occurred in which fingerprint security was released even with an unregistered fingerprint or silicone case, which was not registered in the Samsung smartphone Galaxy 10, which introduced the ultrasonic fingerprint recognition method in Korea, became an issue in 2019. In this regard, Samsung has enhanced security by updating its software.

The security problem in the above case is because the two-dimensional ultrasonic fingerprint recognition method is applied to fingerprint authentication. Recently, in 2020, Samsung is reporting to the media that the Galaxy Note 20 will be equipped with an improved ultrasonic fingerprint recognition technology called 3D Sonic max from Qualcomm. However, as for the currently reported 3D Sonic Max's ultrasonic fingerprint recognition method, the technical details that 3D fingerprint mapping was chosen to enhance security have not been disclosed, while the method of performing security recognition with one fingerprint is not disclosed. By detecting fingerprints at the same time and checking with AND conditions, security is improved and improvements are being announced.

Looking at Qualcomm's recently published prior patent, US 2020-0175291 (published on June 4, 2020), Qualcomm's ultrasonic fingerprint sensor does not use a method of detecting the valleys and ridges of a fingerprint with a nano-rod structure. Qualcomm's prior patent discloses that an ultrasonic sensor is used, but the ultrasonic sensor is capacitively detected as a fingerprint authentication principle. Therefore, the conventional ultrasonic sensor uses an ultrasonic sensing method using a PZT element as a sensing principle, but maps a fingerprint in two dimensions by capacitive sensing similar to a capacitive sensing method. Therefore, authentication is performed only when a finger is in contact despite the ultrasonic principle.

In the conventional two-dimensional ultrasonic sensor, the performance of software that determines the degree of capacitiveness is important in determining the security of a fingerprint as the 'capacitiveness' of ultrasound is ultimately a factor that distinguishes fingerprints. For this reason, it is believed that Samsung's Galaxy 10 software security update has been carried out. Since the two-dimensional fingerprint mapping information is a method of reading the 'pattern' of a fingerprint, if another person's fingerprint is copied using a tape, etc., there is a limit to security because it cannot be distinguished from being duplicated.

Considering the conventional technology trends, the implementation of an ultrasonic sensor capable of three-dimensional fingerprint mapping can be a game changer in the conventional fingerprint recognition market. In this regard, the Applicant's Prior Registration Patent No. 10-2070851 (Manufacturing method of an ultrasonic fingerprint sensor using a nanorod structure) is a filling-sintering method through molding fine nanorods, and the implementation of an array of a plurality of precise nanorods is It was confirmed that it is possible. The applicant's prior patent discloses the possibility of an ultrasonic sensor capable of flip-chip bonding by suggesting a process completely different from the MEMS process.

Accordingly, the present applicant intends to propose an improved structure of an ultrasonic sensor die suitable for packaging and a structure of an ultrasonic sensor die in which flexibility can be secured, based on the prior art. In addition, it is intended to provide an ultrasonic sensor for building three-dimensional fingerprint information by packaging the proposed sensor die.

An object of the present invention is to provide a sensor die and an ultrasonic sensor advantageous for manufacturing and mass production by bonding and packaging as a flip chip without wiring on a PCB substrate.

The present invention provides flip-chip bonding of a plurality of PZT nanorods by controlling a plurality of PZT nanorods as a single electrical contact in a bundle, rather than individually flip chip bonding a plurality of PZT nanorods in a flip chip sensor die. In this process, we want to provide an ultrasonic sensor that can map a fingerprint in three dimensions by specifying the position of each nanorod.

Another object of the present invention is to provide an ultrasonic sensor having a structure in which flexibility is secured so that it can be applied to a flexible display.

In order to achieve the above object, the present invention provides an ultrasonic sensor,

A sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to sense a user's fingerprint, and a first electrode in electrical contact with the nanorods along a line in the first axial direction of the nanorods to constitute one surface of the sensing unit and a second electrode that is in electrical contact with the nanorod along a line in the second axial direction of the nanorod to configure the other surface of the sensing unit, and is in electrical contact with one end of the first electrode and is in electrical contact with the nanorod in the first axial direction A first flip chip electrode for integrally distributing an electrical signal to the nanorods positioned at a sensor die configured with a second flip chip electrode; and a solder ball is formed at one end or the other end of the first axis in the line in the first axis direction of the arrayed nanorods to contact the first flip chip electrode, and one end of the second axis in the line in the second axis direction of the nanorods or an ultrasonic sensor substrate having a solder ball formed on the other end to make contact with the second flip-chip electrode, and including an ultrasonic sensor substrate formed to be less than 1/2 of the number of the nanorods in which the solder balls bonded to the sensor die are arrayed, wherein the sensor die is the It is characterized in that it is flip-chip bonded to the ultrasonic sensor substrate.

In addition, the present invention is an ultrasonic sensor,

A sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to sense a user's fingerprint, and a first electrode in electrical contact with the nanorods along a line in the first axial direction of the nanorods to constitute one surface of the sensing unit and a second electrode that is in electrical contact with the nanorod along a line in the second axial direction of the nanorod to configure the other surface of the sensing unit, and is in electrical contact with one end of the first electrode and is in electrical contact with the nanorod in the first axial direction A first flip chip electrode for integrally distributing an electrical signal to the nanorods positioned at a sensor die configured with a second flip chip electrode; A solder ball is formed at one end or the other end of the first axis in the line in the first axis direction of the arrayed nanorods to contact the first flip chip electrode, and one end of the second axis in the line in the second axis direction of the nanorods or an ultrasonic sensor substrate having a solder ball formed on the other end and contacting the second flip-chip electrode; and a control unit for calculating the position of the nanorod of the ultrasonic signal transmitted and received by a coordinate combination of a solder ball formed in a line in the first axis direction of the nanorod and a solder ball formed in a line in the second axis direction of the nanorod , wherein the sensor die is flip-chip bonded to the ultrasonic sensor substrate.

In addition, the present invention is an ultrasonic sensor,

A sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to sense a user's fingerprint, first and second electrodes applying a voltage to the sensing unit, and the sensing for flip-chip bonding of the first and second electrodes a sensor die including flip-chip electrodes forming bumps through which electrical signals are passed to the outside of the negative electrode; an ultrasonic sensor substrate formed in a zigzag shape with respect to an axis in which the solder ball is in contact with the flip chip electrode and through which an electrical signal is passed during flip chip bonding of the sensor die; and a coordinate combination of a solder ball formed in a line in the first axial direction of the nanorod and a solder ball formed in a line in the second axial direction of the nanorod to calculate the position of the nanorod of the ultrasonic signal transmitted and received, and the nanorod It is another feature to include a control unit that forms three-dimensional fingerprint data by mapping the height (z-axis) information of the valleys or ridges of the fingerprint using the ultrasonic signal received at the position coordinates of .

According to the present invention, one flip-chip electrode collectively performs electrical bonding of nanorods arranged in a row or column for ultrasonic sensing. Accordingly, during packaging on the PCB sensor substrate, the area of the bump that is electrically contacted is reduced to less than half the number of the arrayed nanorods.

In addition, according to the present invention, the coordinates of one nanorod can be estimated using two flip-chip electrodes, and one nanorod can transmit an ultrasonic telegram with the time difference of the pulse voltage, so that the two functions of the ultrasonic transmitter and the receiver are can be performed integrally. Accordingly, the configuration of the ultrasonic sensor die can be simplified.

In addition, according to the present invention, the nanorods and adjacent electrodes that are in line contact are disposed in opposite directions, and the lengths of the exposed terminals are configured to be different from each other, so that the area of the electrical contact can be stably secured widely, so that the packaging of the fine nanorods There are advantages to being able to be angry.

In addition, according to the present invention, the upper and lower electrodes that suppress the structural flexibility of the nanorods are provided in a twisted elastic structure. Although the present invention has a stacked structure in which electrodes are bound on top and bottom of the nanorods, predetermined flexibility is secured, so that the application area can be expanded to flexible displays or wearable devices.

As described above, the present invention provides an ultrasonic sensor that is easily packaged by bonding to a PCB ultrasonic sensor substrate by flip-chip without wiring. Such a three-dimensional ultrasonic fingerprint sensor cannot be duplicated, does not require a touch, and can map fingerprint information without a fingerprint contact. In addition, there is no need to be exposed to the outer surface of the display because it is unnecessary to determine the capacitive or capacitive property that must be directly contacted, and it has an advantage that it can be designed by ambush at a desired location of the device.

1 shows a perspective view of a sensor die according to an embodiment of the present invention;

Fig. 2 shows a top view of the sensor die of Fig. 1;

3 is a schematic diagram illustrating a state in which three-dimensional fingerprint information is acquired through a fingerprint mapping process of a sensor die according to an embodiment of the present invention.

4 shows the steps of a method for manufacturing a sensor die according to an embodiment of the present invention.

5 shows a top view of a sensor die according to another embodiment of the present invention.

6 shows an ultrasonic sensor according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the contents described in the accompanying drawings. However, the present invention is not limited or limited by the exemplary embodiments. The same reference numerals provided in the respective drawings indicate members that perform substantially the same functions.

Objects and effects of the present invention can be naturally understood or made clearer by the following description, and the objects and effects of the present invention are not limited only by the following description. In addition, in the description of the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

1 shows a perspective view of a sensor die 10 according to an embodiment of the present invention.

Referring to FIG. 1 , the sensor die 10 may include a sensing unit 11 , a first electrode 13 , a second electrode 15 , a flip chip electrode 17 , and a base plate 19 . . In the sensor die 10 according to the embodiment of the present invention, bumps soldered to the ultrasonic sensor substrate (PCB substrate) during packaging are limited to the flip-chip electrode 17 , so that the number of nanorods 100 of the sensing unit 11 is greater than that of the sensor die 10 . It may consist of few electrical contacts. In other words, in the sensor die 10 according to the present embodiment, only the flip-chip electrode 17 is a region in which electrical contact is made to the ultrasonic sensor substrate. Therefore, the operation of bonding each of the numerous nanorods 100 is not required.

The packaging of the sensor die 10 according to the present embodiment includes the flip chip electrode 17 of the sensor die 10 on the ultrasonic sensor substrate 30 ( FIG. 6 ) in which a conductive circuit is formed at a position corresponding to the flip chip electrode 17 . This bonding is made, and flip-chip bonding may be performed by thermocompression or underfill technique.

In the sensor die 10 according to the present embodiment, the nanorod 100, which is a piezoelectric sensor, individually detects the height of the peak or valley of the fingerprint, and maps the user's fingerprint in three dimensions. Accordingly, the nanorods 100 of the sensor die 10 have a size corresponding to a pixel, which is a pixel during fingerprint mapping. The nanorods 100 are provided in a size ranging from tens to hundreds of micrometers (㎛) to distinguish the sensitivity of the valleys and ridges of the fingerprint. In the sensor die 10, a sufficient number of nanorods 100 for detecting a fingerprint are arrayed in nxn to constitute a sensing region. Hereinafter, a region in which the nanorods 100 are arrayed to sense a user's fingerprint is defined as the sensing unit 11 .

For three-dimensional ultrasonic fingerprint sensing according to the present embodiment, at least several hundred fine nanorods 100 should be arranged, and each nanorod 100 may be bonded to a circuit board for transmitting and receiving electrical control and electrical signals. A contact path must be formed. Since wiring bonding all of the numerous nanorods 100 in the 3D ultrasonic fingerprint sensor is a commercialized method that is close to impossible, the importance of implementing flip-chip bonding has been described above in the background.

Even if the flip-chip bonding method is adopted, it is not technically easy to bond each of the nanorods 100 to the substrate without a defect in the bonding portion for hundreds of nanorods 100 having a fine pitch interval. This is because the circuit lines of the ultrasonic sensor PCB board must be printed in micro units, the insulation between the pitches of the circuits must be perfect, and short circuits that can occur due to microscopic soldering expansion caused by thermocompression during bonding must be prevented.

Accordingly, the sensor die 10 according to the present embodiment integrates hundreds of nanorods 100 for each axis to integrate electrical signals and form bumps as a common electrical contact area. The sensor die 10 is a flip-chip method in which bumps, which are common electrical contact areas, are soldered, and electrical signals are integrated into a single contact point with a plurality of nanorods 100 .

Therefore, it is not necessary to bond hundreds of nanorods 100 , and the electrical contact can be simplified and configured as an area outside the sensing unit 11 . In this case, as the electrical contacts share the plurality of nanorods 100 , a new technical issue of specifying each position of the nanorods 100 occurs. Hereinafter, in the present embodiment, a unique ultrasonic sensing algorithm capable of specifying the coordinates of each nanorod 100 even though the bump is configured as a common electrical contact area is presented. Hereinafter, a detailed configuration of the sensor die 10 will be described.

The sensing unit 11 may detect a user's fingerprint by arraying a plurality of nanorods 100 having a piezoelectric effect. The sensing unit 11 may be filled with an insulating material 101 that insulates between the nanorods 100 for detecting the valleys and peaks of the user's fingerprint with ultrasonic waves and the nanorods 100 . The configuration of the insulating material 101 is filled in order to insulate both the nanorods 100 and the pitch of the flip-chip electrode 17, but for the convenience of classification and explanation of the configuration, it is not shown in FIG. 1 and is expressed on the filled area. became

Nanorod 100 is a PZT (PbZrO ₃ )-based compound, PST (Pb, Sc, Ta) O ₃ -based compound, quartz, (Pb, Sm)TiO ₃ -based compound, PMN-PT-based compound, PVDF-based compound, and PVDF At least one selected from the group consisting of -TrFe-based compounds may be used. The piezoelectric material for ultrasonic sensing according to the present embodiment has a structure of a filler type, not a thin film type. The insulating material 101 may be at least one selected from the group consisting of resin materials such as epoxy, polyimide, neoprene, polyethylene, PVDF, OCR, OCA, and RU. The insulating material 101 is preferably selected from a flexible resin material or an epoxy-based material.

The nanorod 100 is a piezoelectric element, and may cause a piezoelectric effect for converting mechanical energy into electrical energy or an inverse piezoelectric effect for causing mechanical displacement by applying electrical energy. A voltage is applied to the nanorod 100 according to the present embodiment through the first electrode 13 and the second electrode 15, and the applied voltage causes mechanical displacement to emit ultrasonic waves. The nanorod 100 has a pillar-type structure and transmits ultrasonic waves on the same z-axis, and the emitted ultrasonic waves are reflected from the fingerprint.

Mechanical displacement of the nanorods 100 is generated by reflected ultrasonic waves, and an output voltage is generated through the first electrode 13 and the second electrode 15 due to the mechanical displacement according to the ultrasonic reception of the nanorods 100 . The ultrasonic sensor substrate, which is a PCB substrate on which the sensor die 10 is packaged, receives an output voltage.

The sensing unit 11 in which the nanorods 100 are arrayed in an nxn array 11 transmits ultrasonic waves from the nanorods 100 by application of a pulse voltage, and the transmitted ultrasonic waves are reflected from the user's fingerprint and are again received by the nanorods 100 . The depth (z) information of the fingerprint may be sensed by using the pulse voltage generated by the nanorods 100 upon reception of ultrasonic waves. The sensing unit 11 enables a three-dimensional mapping of a user's fingerprint with the plane coordinate (x-y) information and the depth (z) information of the arrayed nanorods 100 .

The sensing unit 11 is configured to receive the ultrasonic wave reflected from the user's fingerprint by means of which the ultrasonic wave was transmitted, so that the nanorod 100 serves as both the ultrasonic wave generating means and the receiving means. In general, an ultrasonic fingerprint sensor includes two components: an ultrasonic wave generating means and an ultrasonic wave receiving means. In the sensing unit 11 according to the present embodiment, the nanorod 100 functions by integrating an ultrasonic generator and a receiver. A control unit provided on the ultrasonic sensor substrate so that the nanorod 100 functions both for generating and receiving ultrasonic waves controls the pulse voltage with a time difference.

That is, when the controller 50 ( FIG. 6 ) for controlling the sensor die 10 , which will be described later in this embodiment, applies a pulse voltage to the sensing unit 11 , the nanorods 100 generate ultrasonic waves and then ultrasonic waves A control voltage is applied in the form of a clock so that the pulse voltage is not applied until the time of receiving . The control unit 50 (FIG. 6) detects the output voltage returned after a predetermined time in micro units from the point in time when the pulse voltage is applied to calculate the height information of the fingerprint. As a result, in this embodiment, as the controller 50 (FIG. 6) controls the applied voltage by setting a clock with a time difference to receive the pulse voltage, the time in micro units may be delayed for fingerprint recognition, but the nanorod ( 100) will be able to combine the two functions of transmitting and receiving.

The first electrode 13 may be in electrical contact with one end of the nanorod 100 to be configured on one surface of the sensing unit 11 . In this embodiment, the first electrode 13 may be in contact with one surface of the A number of nanorods 100 arranged in a line of the first axis (x axis) in the array of the nanorods 100 of the sensing unit 11 . there is. In this case, the second electrode 15 may be in contact with the other surface of the B nanorods 100 arranged in a line of the second axis (y axis) in the array of the nanorods 100 of the sensing unit 11 . .

In the example of FIG. 1 , the first electrodes 13 are line-contacted along the first axis of the nanorods 100 arranged in a line on the upper surface of the nanorods 100 . The first electrode 13 is in contact with the nanorods 100 of the first axis in the same direction as the upper surface of the nanorod 100 to constitute the upper surface of the sensing unit 11 . The second electrode 15 is line-contacted along the second axis of the nanorods 100 arranged in a line on the lower surface of the nanorods 100 . In this embodiment, the first axis and the second axis may be orthogonal to each other. The first axis and the second axis represent different axes, and the reason for having different axes is to specify the coordinates of the nanorods 100 later. The second electrode 15 is in contact with the nanorods 100 of the second axis in the same direction as the lower surface of the nanorod 100 to constitute the lower surface of the sensing unit 11 .

In the sensor die 10 according to the present embodiment, the flip-chip electrodes 17 soldered to the ultrasonic sensor substrate during packaging may be formed to be less than 1/2 of the total number (AxB) of the nanorods 100 . Counting the structures of the first and second electrodes 13 and 15 described above, it is assumed that the number of nanorods 100 is N, the number of nanorods 100 on the first axis is A, and the number of nanorods 100 on the second axis ), if the number is B, N = AxB. The first and second electrodes 13 and 15 are contacted with a line by integrating all the nanorods 100 in one column or row along different axes (x-axis and y-axis). Accordingly, the exposed ends of the first and second electrodes 13 and 15 to be terminals are reduced to less than 1/2 of the total number AxB of the nanorods 100 .

FIG. 2 shows a top view of the sensor die 10 of FIG. 1 . A coupling relationship between the first electrode 13 , the second electrode 15 , and the flip-chip electrode 17 will be described with reference to FIG. 2 .

The first electrode 13 may alternately be in line contact with the nanorod array so that an end of the electrode exposed to be in electrical contact with the flip chip electrode 17 faces in a direction opposite to the adjacent first electrode 13 . The first electrode 13 is in line contact with the nanorod 100 in the direction of the first axis, is formed to have a length longer than the first axis of the sensing unit 11, and one end is exposed. It is preferable that the end of the first electrode 13 is exposed to only one of both sides of the sensing unit 11 . The end exposed to one side functions as a terminal. The terminal is connected to the flip chip electrode 171 .

At this time, it is preferable that the exposed terminals of the first electrode 13 are staggered so as to face different sides among both sides of the sensing unit 11 . Accordingly, the interval between the flip chip electrodes 171, which will be described later, may be twice as wide as the pitch interval of the nanorod 100 array.

In a more preferred embodiment, the first electrode 13 has an exposure length different from that of the adjacent first electrode 13 in which an end of the electrode exposed in order to make electrical contact with the flip chip electrode 171 is exposed in the same direction. Referring to FIG. 1 , the adjacent first electrodes 13 with the ends of the first electrodes 13 exposed in the same direction correspond to the second spaced apart first electrodes 13 . This is because the ends of the first electrodes 13 spaced apart from each other are staggered in different directions.

The fact that the adjacent first electrodes 13 with the ends of the first electrodes 13 exposed in the same direction and the exposure lengths of the terminals are different from each other gives a wider gap to the flip-chip electrode 171 , which will be described later. Accordingly, bonding can be facilitated during packaging of the sensor die 10 and contact defects can be minimized.

The second electrode 15 may be electrically contacted to the other end of the nanorod 100 to be configured on the other surface of the sensing unit 11 . 1 , the other end of the nanorod 100 may be the lower end of the nanorod 100 , and the other surface of the sensing unit 11 may be the lower surface of the sensing unit 11 .

The second electrode 15 may alternately be in line contact with the nanorod 100 array so that the end of the electrode exposed to make electrical contact with the flip chip electrode 17 faces in the opposite direction to the adjacent second electrode 15 . there is. The second electrode 15 is line-contacted with the nanorod 100 in the direction of the second axis, is formed to have a length longer than the second axis of the sensing unit 11, and one end is exposed. It is preferable that an end of the second electrode 15 is exposed to only one of both sides of the sensing unit 11 . The end exposed to one side functions as a terminal. The terminal is connected to the flip chip electrode 173 .

In this case, it is preferable that the exposed terminals of the second electrode 15 face different sides among both sides of the sensing unit 11 . Accordingly, the interval between the flip chip electrodes 173, which will be described later, may be twice as wide as the pitch interval of the nanorod 100 array.

In a more preferred embodiment, the second electrode 15 has an exposure length different from that of the adjacent second electrode 15 in which an end of the electrode exposed in order to make electrical contact with the flip chip electrode 17 is exposed in the same direction.

Referring to FIG. 1 , the adjacent second electrodes 15 with the ends of the second electrodes 15 exposed in the same direction correspond to the second electrodes 15 spaced apart from each other. This is because the ends of the second electrodes 15 spaced apart first are displaced in different directions. The difference between the exposure lengths of the terminals and the adjacent first electrodes 15 in which the ends of the second electrodes 15 are exposed in the same direction provide a wider gap to the flip-chip electrode 173, which will be described later. Accordingly, bonding can be facilitated during packaging of the sensor die 10 and contact defects can be minimized.

The flip-chip electrode 17 may be in electrical contact with one end of the first electrode 13 or the second electrode 15 , so that electrical signals of the N nanorods 100 may be integrally energized. The flip-chip electrode 17 may be divided into a first flip-chip electrode 171 and a second flip-chip electrode 173 .

The flip chip electrode 17 may be provided as a conductive material including a material selected from the group consisting of Si, GaAs, InAs, InN, Ge, ZnO, and Ga ₂ O ₃ . As the physical properties of the flip-chip electrode 17, it is preferable that the sheet resistance shrinkage is 100 Ω or less, and the shrinkage ratio is 3 to 5%.

The first flip-chip electrode 171 is an electrode that is bound to the first electrode 13 and applies a voltage to the first electrode 13 . The second flip-chip electrode 173 is an electrode coupled to the second electrode 15 to apply a voltage to the second electrode 15 .

The flip chip electrode 17 may be provided to have the same pillar structure as that of the nanorod 100 when it is bound to an electrode positioned on the upper surface of the nanorod 100 . When the flip-chip electrode 17 is bound to an electrode located on the lower surface of the nanorod 100 , it may refer to a bump region formed in the terminal of the electrode that is in line contact with the lower surface of the nanorod 100 . The flip-chip electrode 17 refers to an electrical contact area for flip-chip bonding the exposed terminals of the first and second electrodes 13 and 15 described above.

The flip-chip electrode 17 is disposed on the outside of the nanorod 100 and provides a bonding area as an outer area of the sensing unit 11 . The flip chip electrode 17 may be manufactured based on a conductive mold. In this regard, it will be described later with reference to FIG. 4 .

The flip chip electrode 17 is in electrical contact with the nanorods 100 in an N:1 relationship by integrally applying a pulse voltage for ultrasonic generation to the N nanorods 100 . Accordingly, in the sensor die 10 according to the present embodiment, the bumps soldered to the ultrasonic sensor substrate during packaging are limited to the flip-chip electrodes 17 , so that the number of electrical contacts of the sensing unit 11 is smaller than the number of nanorods 100 . can be composed of

The base plate 19 may insulate the lower surface of the second electrode 15 located in the sensing unit 11 among regions of the second electrode 15 configured on the other surface of the sensing unit 11 . At this time, one end of the second electrode 15 is exposed to the outside of the sensing unit 11 in the axial direction, and bumps are formed at the exposed end of the second electrode 15 to form the flip-chip electrode 173 . configurable.

3 is a schematic diagram illustrating a state in which three-dimensional fingerprint information is acquired through a fingerprint mapping process of the sensor die 10 according to an embodiment of the present invention.

Referring to FIG. 3 , the sensor die 10 according to the present embodiment is packaged on a PCB ultrasonic sensor substrate, and a pulse voltage is applied from the controller. The pulse voltage is applied to the soldered flip-chip electrode 17 to form a voltage difference in the nanorods 100 . The nanorods 100 emit ultrasonic waves toward the user's fingerprint 3 by a piezoelectric effect. A parallax is formed when the ultrasonic waves reflected from the user's fingerprint 3 reach the nanorods 100 according to the height difference between the valleys or the peaks of the fingerprint 3 . The nanorod 100 that has received the ultrasonic wave reflected from the fingerprint 3 generates a pulse signal with an inverse piezoelectric effect and outputs it to the controller of the PCB ultrasonic sensor substrate. The control unit calculates height information of the fingerprint 3 based on the parallax and intensity of the output pulse signal.

4 shows the steps of a method for manufacturing a sensor die 10 according to an embodiment of the present invention. Referring to FIG. 4 , in the sensor die 10 according to the present embodiment, the nanorods 100 are manufactured by using a conductive substrate to be etched with the flip chip electrode 17 as a mold as a mold. The method for manufacturing the sensor die 10 includes a conductive mold generation step, a nanorod generation step, a side electrode generation display step, a conductive mold etching step, an insulating material filling step, a lower electrode forming step, a dummy substrate bonding step, and an upper electrode forming step. may include steps.

In the step of generating the conductive mold, a plurality of rod generation holes spaced apart from each other by etching the conductive substrate are generated. In the nanorod generating step, the nanorods 100 are created by filling the plurality of rod generating holes with a nano piezoelectric material.

The step of displaying the side electrode generating unit is a step of marking the position of the side electrode on the edge of the conductive mold on one side of the rod generating hole. In FIG. 4 , the side electrode may be the flip-chip electrode 17 described above.

In the conductive mold etching step, the remaining conductive molds are first etched to generate nanorods and side electrodes, except for the nanorods, the marked side electrode generating part, and the conductive substrate base connecting them.

In the insulating material filling step, the insulating material is filled in the portion etched through the conductive mold etching step.

In the lower electrode forming step, secondary etching is performed so that one end of the nanorod and the side electrode surrounded by the insulating material is exposed by filling the insulating material, and a lower electrode is formed at one end of the exposed nanorod and the side electrode.

In the step of bonding the dummy substrate, the dummy substrate is adhered to the surface on which the lower electrode is formed. The dummy substrate may be the above-described base plate 19 .

In the upper electrode forming step, the upper electrode is formed at the other end of the exposed nanorod and the side electrode by removing the conductive substrate base connecting the nanorod and the side electrode.

The manufacturing process of the sensing unit 11 using the conductive mold according to the embodiment of FIG. 4 is a completely different approach from the conventional MEMS process, and the substrate is etched through a photolithography method to fabricate a nanorod based on a mold. Reference can be made to the prior registered patent No. 10-2070851 of the present applicant related to this manufacturing technique.

5 shows a top view of a sensor die according to another embodiment of the present invention.

The sensor die 10 according to this embodiment includes a sensing unit 11 in which a plurality of nanorods 100 having a piezoelectric effect are arrayed to detect a user's fingerprint; a first electrode 13 that is in electrical contact with the nanorod 100 along a line in the first axial direction of the nanorod 100 to form one surface of the sensing unit 11; a second electrode 15 that is in electrical contact with the nanorod 100 along a line in the second axial direction of the nanorod 100 to configure the other surface of the sensing unit 11; a first flip-chip electrode 171 that is in electrical contact with one end of the first electrode 13 and integrally distributes an electrical signal to the nanorods 100 positioned in a line in the first axial direction; and a second flip-chip electrode 173 that is in electrical contact with one end of the second electrode 15 and integrally distributes an electrical signal to the nanorods 100 positioned in a line in the second axis direction.

In the embodiment of FIG. 5 , the sensing unit 11 and the flip-chip electrode 17 are the same as those described above in the embodiments of FIGS. 1 to 4 , and overlapping references are omitted. In the embodiment of FIG. 5 , the structure of the first and second electrodes 13 and 15 for flexibility is presented.

The sensor die 10 according to the present embodiment has a pillar-type structure in which both the nanorods 100 and the flip-chip electrodes 171 have a micro or nano-scale thickness. In addition, when the nanorods 100 are arrayed at a fine pitch interval and a known flexible insulating material is filled between the pitches, there is no problem in the flexibility of the nanorods 100 and the flip chip electrode 171 .

However, the ultrasonic sensor module according to the present embodiment has a structure in which the electrodes 13 and 15 are coupled to the upper and lower surfaces of the nanorods 100 in different axes. In the embodiment of FIG. 1 , it is difficult to form flexibility due to the structure of the electrodes 13 and 15 stacked on the top and bottom of the nanorod 100 .

Accordingly, the first electrode 13 or the second electrode 15 of the present embodiment is provided in a twisted shape in which a line extending along an axis in electrical contact with the nanorod 100 imparts a predetermined elasticity in the axial direction. . More specifically, the twisted shape of the electrode referred to in this specification refers to a serpentine or zigzag shape.

Referring to FIG. 4 described above, the first electrode 13 or the second electrode 15 can be easily manufactured because the line width and shape can be freely changed during the forming process after the mold is etched. The sensor die 10 according to the present embodiment does not necessarily require the user's fingerprint 3 to come into contact with the sensing unit 11 according to the three-dimensional ultrasonic sensing principle. The sensor die 10 may be installed to be buried under various devices and displays requiring security. In addition, as flexible displays and devices have recently diversified, it is desirable that the ultrasonic sensor be implemented to ensure flexibility.

In the sensor die 10 according to this embodiment, the sensing unit 11 is not provided in a plate shape, but as an array of fine nanorods, and the stacked electrode structure also has a predetermined elasticity, so it can be applied to a flexible device. .

6 shows an ultrasonic sensor 1 according to an embodiment of the present invention.

Referring to FIG. 6 , the ultrasonic sensor 1 may be manufactured by flip-chip bonding the sensor die 10 described above in FIGS. 1 to 5 to the ultrasonic sensor substrate 30 . The detailed configuration of the sensor die 10 omits the use of overlapping bar as described above.

The ultrasonic sensor substrate 10 is a circuit board to which the sensor die 10 is bonded, and the solder balls 31 are formed at the positions of the flip- chip electrodes 171 and 173 of the sensor die 10 and include the control unit 50 . can

The solder ball 31 is formed at one end or the other end of the first axis in the line in the first axis direction of the nanorod 100 . In addition, the solder ball 31 is formed at one end or the other end of the second axis in the line in the second axis direction of the nanorod 100 .

Since the solder ball 31 is a terminal of the substrate that is in electrical contact with the first flip-chip electrode 171 or the second flip-chip electrode 173 , the arrangement of the solder ball 31 is the same as the arrangement of the flip-chip electrode 17 described above. same. Accordingly, the solder balls 31 are alternately arranged in adjacent arrays. This is because the first flip-chip electrode 171 or the second flip-chip electrode 173 are alternately disposed at one end or the other end based on the same axis.

In addition, the solder balls 31 are arranged in a zigzag with respect to the arrayed axis. In more detail, the solder balls 31 formed on one end or the other end of the first axis are arranged in the second axis direction. The solder balls 31 adjacent to each other in the second axial direction become the second spaced solder balls 31 due to the above-described misalignment relationship. Here, since the exposure lengths of the first and second electrodes 13 and 15 are different from each other, the positions of the solder balls 31 arranged in the second axis direction are also arranged in a zigzag manner. Accordingly, each of the solder balls 31 has a sufficient print area.

The ultrasonic sensor substrate 30 is connected to the contact point of the solder ball 31 , and may be a PCB substrate on which a circuit pattern is designed and printed in consideration of element arrangement. The control unit 50 may be configured as a module on the PCB substrate of this embodiment.

The control unit 50 calculates the position of the nanorods 100 of the ultrasonic signal transmitted and received by the coordinate combination of the solder ball 31 formed in the first axis direction line and the solder ball 31 formed in the second axis direction line. there is.

The controller 50 may control an applied voltage for driving the nanorods 100 . The controller 50 may apply a pulse voltage for driving the piezoelectric element in the form of a clock. In the duty ratio of the clock signal, the control unit 50 sets the duty ratio including a delay time in consideration of the time until a predetermined electrical signal is applied from the nanorod 100 after the pulse voltage of the clock signal is applied. can be set. The controller 50 may consider an electrical signal returned after a predetermined time (in μm unit) after application of the pulse voltage as an output signal for fingerprint mapping.

The control unit 50 may include a first operation module 501 and a second operation module 503 .

Referring to FIG. 6 , the first operation module 501 may calculate the position P of the nanorods 100 as the axial intersection between the solder ball x of the first axis and the solder ball y of the second axis. In the example of FIG. 6 , all of the nanorods 100 of the sensing unit 11 transmit ultrasonic waves when a pulse voltage is applied to receive ultrasonic waves reflected at different times.

The time of the received ultrasound is determined from the depth information of the valleys and ridges of the fingerprint. When the ultrasonic wave is received, a pulse voltage is again output through the solder ball 31 . In this case, when a pulse voltage is simultaneously sensed at the solder ball at the x point and the solder ball at the y point, the corresponding signal may be specified as being the nanorod 100 located at the p point. The nanorod 100 located at the p point may be set to coordinates (x,y).

The second operation module 503 maps the height (z-axis) information of the valleys or ridges of the fingerprint by using the ultrasound signal received at the position coordinates (x, y) of the nanorods 100 of the first operation module 501 . can do. In this embodiment, the received ultrasonic signal may be an electrical signal formed as mechanical displacement is generated in the nanorods 100 by reflected ultrasonic waves.

The height (z-axis) information of the valleys or ridges of the fingerprint may be calculated from the information of the electrical signal. In more detail, the second operation module 503 may calculate the z-axis information by measuring the time difference of the electrical signal received through the solder ball 31 . This embodiment is another embodiment, and by applying a more complex algorithm, the strength of the electrical signal or the use of voltage or current information is not limited.

By performing the second operation module 503 , the control unit 50 may construct 3D fingerprint information of (x, y, z). The control unit 50 forms three-dimensional fingerprint data as a result of the first operation module 501 and the second operation module 503 , and may be provided as a security verification means capable of recognizing a fingerprint even in a non-contact state.

Although the present invention has been described in detail through representative embodiments above, those of ordinary skill in the art to which the present invention pertains will understand that various modifications are possible within the limits without departing from the scope of the present invention with respect to the above-described embodiments. will be. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by all changes or modifications derived from the claims and equivalent concepts as well as the claims to be described later.

3: Fingerprint

1: Ultrasonic sensor

10: sensor die

30: ultrasonic sensor board

31: solder ball

11: Sensing unit

100: nano rod

101: insulation material

13: first electrode

15: second electrode

17: flip chip electrode

171: first flip chip electrode

173: second flip chip electrode

19: base plate

50: control unit

501: first operation module

503: second operation module

According to the present invention, the packaging of the ultrasonic sensor is easy, the fingerprint is detected in a 3D non-contact method, and it can be implemented by being inserted as an under-display in various devices such as monitors and smart phone terminals.

Claims (19)

1. A sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to sense a user's fingerprint, and a first electrode in electrical contact with the nanorods along a line in the first axial direction of the nanorods to constitute one surface of the sensing unit and a second electrode that is in electrical contact with the nanorod along a line in the second axial direction of the nanorod to configure the other surface of the sensing unit, and is in electrical contact with one end of the first electrode and is in electrical contact with the nanorod in the first axial direction A first flip-chip electrode for integrally distributing an electrical signal to the nanorods positioned at a sensor die configured with a second flip chip electrode; and

   A solder ball is formed at one end or the other end of the first axis in the line in the first axis direction of the arrayed nanorods to be in contact with the first flip chip electrode, and one end of the second axis in the line in the second axis direction of the nanorods or Solder balls are formed at the other end to be in contact with the second flip-chip electrode, and include an ultrasonic sensor substrate formed to be less than 1/2 the number of the nanorods in which the solder balls bonded to the sensor die are arrayed,

   The ultrasonic sensor, characterized in that the sensor die is flip-chip bonded to the ultrasonic sensor substrate.
2. The method of claim 1,

   The ultrasonic sensor substrate,

   A control unit for calculating the position of the nanorod of the ultrasonic signal transmitted and received by a coordinate combination of a solder ball formed in a line in the first axis direction of the nanorod and a solder ball formed in a line in the second axis direction of the nanorod further comprising Ultrasonic sensor, characterized in that.
3. 3. The method of claim 2,

   The control unit is

   a first arithmetic module for calculating the position of the nanorod at the axial intersection of the first axis solder ball and the second axis solder ball; and

   and a second arithmetic module for mapping the height (z-axis) information of the valleys or ridges of the fingerprint using the ultrasonic signal received from the position coordinates of the nanorods of the first arithmetic module.
4. 4. The method of claim 3,

   The control unit is

   By forming three-dimensional fingerprint data with the result of the first calculation module and the result of the second calculation module,

   Ultrasonic sensor, characterized in that the user's fingerprint information can be mapped even if the fingerprint does not come into contact with the sensor die.
5. The method of claim 1,

   The solder ball is

   Solder balls are alternately formed on one end or the other end of the first axis in the line in the first axis direction of the arrayed nanorods to contact the first flip chip electrode,

   Solder balls are alternately formed on one end or the other end of the second axis in the line in the second axis direction of the nanorods to contact the second flip chip electrode.
6. 6. The method of claim 5,

   The solder ball is

   Ultrasonic sensor, characterized in that formed in a zigzag based on the arranged axis.
7. The method of claim 1,

   The flip-chip electrode configured on the sensor die,

   A pulse voltage for generating ultrasonic waves is integrally applied to the N nanorods to make electrical contact with the nanorods in an N:1 relationship, and bumps soldered to the ultrasonic sensor substrate during packaging are limited to flip-chip electrodes, and the sensing Ultrasonic sensor, characterized in that it consists of electrical contacts less than the number of negative nanorods.
8. The method of claim 1,

   The sensing unit,

   Ultrasound is transmitted from the nanorods by the application of a pulse voltage, the transmitted ultrasound is reflected from the user's fingerprint and received by the nanorod again, and the depth of the fingerprint is obtained using the pulse voltage generated by the nanorod upon receiving the ultrasound. (z) detect information;

   Ultrasonic sensor, characterized in that the three-dimensional mapping of the user's fingerprint with the plane coordinate (x-y) information and the depth (z) information of the arrayed nanorods.
9. The method of claim 1,

   The sensing unit,

   Ultrasonic sensor, characterized in that by receiving the ultrasonic wave reflected from the user's fingerprint by means of transmitting the ultrasonic wave, the nanorod serves as both an ultrasonic wave generating means and a receiving means.
10. The method of claim 1,

    The first electrode is

    The sensing unit is in contact with one surface of the A number of nanorods arranged in a line of a first axis (x-axis) in the array of nanorods,

    The second electrode is

    The sensing unit is in contact with the other surface of the B nano-rods arranged in a line of a second axis (y-axis) in the array of nano-rods,

    The ultrasonic sensor, characterized in that the flip chip electrode soldered to the ultrasonic sensor substrate during packaging is formed to be less than 1/2 of the total number (AxB) of the nanorods.
11. 11. The method of claim 10,

    The first electrode or the second electrode,

    An ultrasonic sensor, characterized in that the line extending along the axis has a twisted shape imparting a predetermined elasticity in the axial direction.
12. The method of claim 1,

    The first electrode is

    The ultrasonic sensor according to claim 1, wherein an end of an electrode exposed to make electrical contact with the flip-chip electrode is alternately line-contacted with the nanorod array so as to face a direction opposite to an adjacent first electrode.
13. 13. The method of claim 12,

    The first electrode is

    An end portion of an electrode exposed to make electrical contact with the flip chip electrode has an exposure length different from that of an adjacent first electrode exposed in the same direction.
14. A sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to sense a user's fingerprint, and a first electrode in electrical contact with the nanorods along a line in the first axial direction of the nanorods to constitute one surface of the sensing unit and a second electrode that is in electrical contact with the nanorod along a line in the second axial direction of the nanorod to configure the other surface of the sensing unit, and is in electrical contact with one end of the first electrode and is in electrical contact with the nanorod in the first axial direction A first flip chip electrode for integrally distributing an electrical signal to the nanorods positioned at a sensor die configured with a second flip chip electrode;

    A solder ball is formed at one end or the other end of the first axis in the line in the first axis direction of the arrayed nanorods to contact the first flip chip electrode, and one end of the second axis in the line in the second axis direction of the nanorods or an ultrasonic sensor substrate having a solder ball formed on the other end and contacting the second flip-chip electrode; and

    A control unit for calculating the position of the nanorod of the ultrasonic signal transmitted and received by a coordinate combination of a solder ball formed in a line in the first axis direction of the nanorod and a solder ball formed in a line in the second axis direction of the nanorod,

    The ultrasonic sensor, characterized in that the sensor die is flip-chip bonded to the ultrasonic sensor substrate.
15. A sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to detect a user's fingerprint, first and second electrodes applying a voltage to the sensing unit, and the sensing for flip-chip bonding of the first and second electrodes a sensor die including flip-chip electrodes forming bumps through which electrical signals are passed to the outside of the negative electrode;

    an ultrasonic sensor substrate formed in a zigzag shape with respect to an axis in which a solder ball is formed in contact with the flip chip electrode during flip-chip bonding of the sensor die and through which an electrical signal is passed; and

    Calculating the position of the nanorod of the ultrasonic signal transmitted and received by a coordinate combination of a solder ball formed in a line in the first axis direction of the nanorod and a solder ball formed in a line in the second axis direction of the nanorod, An ultrasonic sensor substrate comprising: a controller for mapping the height (z-axis) information of the valleys or peaks of the fingerprint using the ultrasonic signal received from the position coordinates to form three-dimensional fingerprint data.
16. a sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to sense a user's fingerprint;

    a first electrode electrically contacted to one end of the nanorod and configured on one surface of the sensing unit;

    a second electrode in electrical contact with the other end of the nanorod and configured on the other surface of the sensing unit; and

    and a flip-chip electrode that is electrically contacted to one end of the first electrode or the second electrode, and through which electrical signals of the N nanorods are integrally energized;

    The flip chip electrode is

    A pulse voltage for generating ultrasonic waves is integrally applied to the N nanorods to make electrical contact with the nanorods in an N:1 relationship, and bumps soldered to the ultrasonic sensor substrate during packaging are limited to flip-chip electrodes, and the sensing A flip-chip sensor die, characterized in that it has fewer electrical contacts than the number of negative nanorods.
17. a sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to sense a user's fingerprint;

    a first electrode in electrical contact with the nanorod along a line in the first axial direction of the nanorod to form one surface of the sensing unit;

    a second electrode in electrical contact with the nanorod along a line in the second axial direction of the nanorod to configure the other surface of the sensing unit;

    a first flip-chip electrode that is in electrical contact with one end of the first electrode and integrally distributes an electrical signal to the nanorods positioned in the line in the first axis direction; and

    a second flip-chip electrode that is in electrical contact with one end of the second electrode and integrally distributes an electrical signal to the nanorods positioned in the line in the second axis direction;

    The sensing unit,

    A pulse voltage applied through the first and second flip-chip electrodes is applied as a clock signal, and after application, the pulse voltage is output in the same path with a time difference. A flip-chip type sensor die, characterized in that the nanorods serve both as an ultrasonic wave generating unit and a receiving unit.
18. a sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to sense a user's fingerprint;

    a first electrode electrically contacted to one end of the nanorod and configured on one surface of the sensing unit;

    a second electrode in electrical contact with the other end of the nanorod and configured on the other surface of the sensing unit; and

    and a flip-chip electrode that is electrically contacted to one end of the first electrode or the second electrode, and through which electrical signals of the N nanorods are integrally energized;

    The first electrode or the second electrode,

    A line extending along an axis in electrical contact with the nanorod is provided in a twisted shape that imparts a predetermined elasticity in the axial direction, making it flexible, and bumps soldered to the ultrasonic sensor substrate during packaging are limited to flip chip electrodes. A flip-chip sensor die, characterized in that it is packaged by chip bonding without wiring.
19. a sensing unit in which a plurality of nanorods having a piezoelectric effect are arrayed to sense a user's fingerprint;

    a first electrode in electrical contact with the nanorod along a line in the first axial direction of the nanorod to form one surface of the sensing unit;

    a second electrode in electrical contact with the nanorod along a line in the second axial direction of the nanorod to configure the other surface of the sensing unit;

    a first flip-chip electrode that is in electrical contact with one end of the first electrode and integrally distributes an electrical signal to the nanorods positioned in the line in the first axis direction; and

    a second flip-chip electrode that is in electrical contact with one end of the second electrode and integrally distributes an electrical signal to the nanorods positioned in the line in the second axis direction;

    The first electrode is alternately line-contacted with the nanorod array so that an end of the electrode exposed to make electrical contact with the flip-chip electrode faces in a direction opposite to the adjacent first electrode,

    The second electrode is alternately line-contacted with the nanorod array so that an end of the electrode exposed to be in electrical contact with the flip-chip electrode faces in a direction opposite to the adjacent second electrode;

    The flip-chip type sensor die, characterized in that the first electrode and the second electrode have different exposure lengths from an adjacent electrode exposed in the same direction at an end of the electrode exposed in order to make electrical contact with the flip-chip electrode.

Images