Packaging test system and method for capacitive fingerprint sensor

Abstract

The present application discloses a packaging test system and method for a capacitive fingerprint sensor. The test board sends a control instruction to the test machine, so that the test machine drives the conductive rubber head to contact the outer surface of the plastic layer of the capacitive fingerprint sensor. The test board controls the capacitive fingerprint sensor to obtain the first fingerprint signal quantity parameter corresponding to the conductive rubber head when the switch control circuit is disconnected; the test board controls the switch control circuit of the test machine to close so that the conductive rubber head is grounded, and the test board controls the capacitive fingerprint sensor to obtain the second fingerprint signal quantity parameter corresponding to the conductive rubber head; the test board determines whether the packaging gap of the capacitive fingerprint sensor meets the packaging requirements based on the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter. The present application tests the packaging gap by capturing the fingerprint signal quantity parameter changes when the conductive rubber head is grounded and not grounded, which can better exclude other factors and make the test result of the packaging gap more accurate.

Description

Technical Field

[0001] The present application relates to the field of chip testing technology, and in particular to a packaging testing system and method for a capacitive fingerprint sensor. Background Art

[0002] Nowadays, fingerprint recognition technology mainly collects fingerprint images through fingerprint sensors. Currently, capacitive fingerprint sensors are one of the mainstream fingerprint sensors. Generally speaking, the sensing electrodes of capacitive fingerprint sensors are designed on the wafer and are packaged in LGA (Land Grid Array). The thickness of the chip will increase after LGA plastic sealing. The thickness of the packaged chip is mainly the thickness from the surface of the plastic sealing layer to the surface of the chip (package gap, Mold Clearance), which affects the clarity of the fingerprint image collected by the capacitive fingerprint sensor. Mold Clearance is a key parameter that needs to be controlled for a capacitive fingerprint sensor. If the consistency of Mold Clearance is not good, it will affect the subsequent chip application.

[0003] In the prior art, the mold clearance detection method is usually to cut the chip and then measure it under a high-precision instrument, or to hollow out the mold clearance on the chip surface and then measure it. Both of the above test methods will damage the tested chip and cause losses. They are only suitable for batch sampling and cannot achieve full testing. Summary of the invention

[0004] The purpose of this application is to provide a packaging test system and method for capacitive fingerprint sensors to solve the technical problem that the existing test system in the prior art is difficult to test or judge whether the packaging gap meets the packaging requirements. The preferred technical solutions among the many technical solutions provided in this application can produce many technical effects as described below.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] The first aspect of the present application provides a packaging test system for a capacitive fingerprint sensor, the packaging test system is used to test the packaging gap of the capacitive fingerprint sensor, the capacitive fingerprint sensor includes a chip and a plastic layer for packaging the chip, the packaging gap is the distance between the surface of the chip and the inner surface of the plastic layer, the packaging test system includes a test board and a test machine for placing the capacitive fingerprint sensor; the test machine is communicatively connected to the test board; the test machine includes a conductive rubber head and a switch control circuit for controlling the grounding of the conductive rubber head; the capacitive fingerprint sensor is placed on the test machine, and the test board sends The control instruction is sent to the test machine, so that the test machine drives the conductive rubber head to contact the outer surface of the plastic packaging layer of the capacitive fingerprint sensor, and the test board controls the capacitive fingerprint sensor to obtain a first fingerprint signal quantity parameter corresponding to the conductive rubber head when the switch control circuit is disconnected; the test board controls the switch control circuit of the test machine to close so that the conductive rubber head is grounded, and the test board controls the capacitive fingerprint sensor to obtain a second fingerprint signal quantity parameter corresponding to the conductive rubber head; the test board determines whether the packaging gap of the capacitive fingerprint sensor meets the packaging requirements according to the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter.

[0007] In some embodiments, the test machine includes a PCB carrier and a socket; the socket is provided with a plurality of socket contacts connected to the chip of the capacitive fingerprint sensor, and the socket connects the chip pins of the capacitive fingerprint sensor to the PCB carrier through a plurality of probes.

[0008] In some embodiments, the testing machine includes a mechanical arm; the mechanical arm is used to drive the conductive rubber head to be pressed down or lifted up, so that the conductive rubber head is close to or away from the outer surface of the plastic packaging layer.

[0009] In some embodiments, the testing machine includes a clamping portion and an elastic component; the clamping portion and the elastic component are arranged in an inner cavity extending inward from the robotic arm, one end of the elastic component is connected to the bottom of the inner cavity, the other end of the elastic component is connected to one end of the clamping portion, and the other end of the clamping portion clamps the conductive rubber head.

[0010] In some embodiments, the test board writes sensor internal circuit gain parameters to the register of the capacitive fingerprint sensor, and the sensor internal circuit gain parameters remain unchanged when acquiring the first fingerprint signal quantity parameters and the second fingerprint signal quantity parameters.

[0011] In some embodiments, the switch control circuit includes a switch element SW1, a first resistor R1, a second resistor R2, a diode D1 and a transistor Q1; the base of the transistor Q1 is connected to one end of the first resistor R1 and one end of the second resistor R2, wherein the other end of the first resistor R1 is connected to the port SW_IO, and the port SW_IO is used to receive the switch control command of the test machine; the emitter of the transistor Q1 is connected to the other end of the second resistor R2 and grounded; the collector of the transistor Q1 is connected to the first end of the switch element SW1 and the anode of the diode D1, wherein the cathode of the diode D1 is connected to the fourth end of the switch element SW1 and connected to the power supply voltage; the second end of the switch element SW1 is grounded, and the third end of the switch element SW1 is connected to the conductive rubber head, wherein a switch is connected between the second end and the third end of the switch element SW1.

[0012] In some embodiments, the test board includes a display screen and a main control chip; the display screen is used to display the test results; and the main control chip is used to send the control instructions to the test machine.

[0013] In some embodiments, the PCB carrier includes a connector J1, which is connected to both the main control chip and the switch control circuit; the second port of the connector J1 is connected to the port SW_IO of the switch control circuit, the fourth port of the connector J1 is connected to the port SCLK of the main control chip, the fifth port of the connector J1 is connected to the port NSS of the main control chip, the sixth port of the connector J1 is connected to the port MOSI of the main control chip, the seventh port of the connector J1 is connected to the port MISO of the main control chip, the eighth port of the connector J1 is connected to the port INT of the main control chip, and the ninth port of the connector J1 is connected to the port RSTN of the main control chip.

[0014] In some embodiments, the PCB carrier includes a socket pad U1, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first TVS tube D2, a second TVS tube D3 and a third TVS tube D4; the first port of the socket pad U1 is connected to the port NSS of the main control chip, the second port of the socket pad U1 is connected to the port SCLK of the main control chip, the third port of the socket pad U1 is connected to the port MISO of the main control chip, the fifth port of the socket pad U1 is connected to the port MOSI of the main control chip, the nineteenth port of the socket pad U1 is connected to the port RSTN of the main control chip, and the twentieth port of the socket pad U1 is connected to the port INT of the main control chip; the twelfth port of the socket pad U1 is connected to the port INT of the main control chip. The socket pad U1 is connected to one end of the second capacitor C2, the eleventh port of the socket pad U1 is connected to the other end of the second capacitor C2 and the anode of the second TVS tube D3, wherein the cathode of the second TVS tube D3 is grounded; the eighteenth port of the socket pad U1 is connected to one end of the third capacitor C3, the cathode of the third TVS tube D4, one end of the first capacitor C1 and the first TVS tube D2, and is grounded; the fourteenth port of the socket pad U1 is connected to the other end of the third capacitor C3 and the anode of the third TVS tube D4; the seventh port, the sixteenth port and the seventeenth port of the socket pad U1 are respectively connected to one end of the first capacitor C1 and the anode of the first TVS tube D2, and are connected to the power supply voltage.

[0015] A second aspect of the present application provides a packaging test method, comprising the following steps: a test board sends a control instruction to a test machine; after the test machine receives the control instruction, the test machine drives a conductive rubber head to abut against the outer surface of a plastic packaging layer of a capacitive fingerprint sensor on the test machine, and the capacitive fingerprint sensor obtains a first fingerprint signal quantity parameter corresponding to the conductive rubber head when a switch control circuit is disconnected; the test board controls the switch control circuit of the test machine to close so that the conductive rubber head is grounded, and the capacitive fingerprint sensor obtains a second fingerprint signal quantity parameter corresponding to the conductive rubber head; the test board determines whether the packaging gap of the capacitive fingerprint sensor meets the packaging requirements based on the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter.

[0016] Implementing one of the above technical solutions of the present application has the following advantages or beneficial effects: In the present application, by driving the conductive rubber head to abut against the outer surface of the plastic layer of the capacitive fingerprint sensor, the first fingerprint signal quantity parameter corresponding to the conductive rubber head when the switch control circuit is disconnected is obtained; at the same time, by controlling the switch control circuit to close so that the conductive rubber head is grounded, the second fingerprint signal quantity parameter corresponding to the conductive rubber head is obtained, and the package gap is judged whether it meets the package requirements according to the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter. In this case, since the fingerprint signal quantity parameter of the capacitive fingerprint sensor is related to the capacitance change, it will be affected by multiple factors including the package gap, etc. The present application tests the package gap by capturing the fingerprint signal quantity parameter change when the conductive rubber head is grounded and not grounded, that is, a single variable, which can better exclude other factors, such as the influence of the downward pressure, etc., so that the test result of the package gap is more accurate. At the same time, it can reduce the damage or loss of the capacitive fingerprint sensor due to the test, and is more suitable for the comprehensive test of the capacitive fingerprint sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. It is obvious that the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0018] Figure 1 is a structural schematic diagram of a packaging test system according to an embodiment of the present application;

[0019] Figure 2 is a schematic diagram of the structure of a capacitive fingerprint sensor according to an embodiment of the present application;

[0020] Figure 3 is a circuit diagram of a switch control circuit according to an embodiment of the present application;

[0021] Figure 4 is a circuit diagram of a connector according to an embodiment of the present application;

[0022] Figure 5 is a circuit diagram of a socket pad of an embodiment of the present application;

[0023] Figure 6 It is a schematic diagram of the structure of the robotic arm of an embodiment of the present application.

[0024] In the figure: 1. Packaging test system; 10. Test machine; 11. Test board; 100. PCB carrier; 101. Socket; 102. Switch control circuit; 103. Conductive rubber head; 104. Robotic arm; 105. Clamping part; 106. Elastic component; 110. Display screen; 111. Main control chip; 2. Capacitive fingerprint sensor; 20. Plastic sealing layer; 21. Chip; 22. Lead wire; 23. Substrate. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present application clearer, the various exemplary embodiments to be described below will refer to the corresponding drawings, which constitute a part of the exemplary embodiments, wherein various exemplary embodiments that may be used to implement the present application are described. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation methods described in the following exemplary embodiments do not represent all implementation methods consistent with the present disclosure. It should be understood that they are only examples of processes, methods, and devices that are consistent with some aspects disclosed in the present application as detailed in the attached claims, and other embodiments may also be used, or the embodiments listed herein may be modified in structure and function without departing from the scope and essence of the present application.

[0026] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", etc. indicate the orientation or positional relationship based on the drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the elements referred to must have a specific orientation, be constructed and operated in a specific orientation. The terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. The term "multiple" means two or more. The terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a communication connection, a direct connection, an indirect connection through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0027] In order to illustrate the technical solution described in the present application, a specific embodiment is provided below, and only the parts related to the embodiment of the present application are shown.

[0028] like Figure 1 As shown, the present application provides a packaging test system 1 for a capacitive fingerprint sensor 2. The packaging test system 1 can be used to test the packaging gap of the capacitive fingerprint sensor 2.

[0029] In some embodiments, the capacitive fingerprint sensor 2 may include a chip 21 and a plastic layer 20 for packaging the chip 21. The packaging gap may be the distance between the surface of the chip 21 and the inner surface of the plastic layer 20. Whether the packaging of the capacitive fingerprint sensor 2 meets the packaging requirements may be determined based on the size of the packaging gap. The chip 21 of the capacitive fingerprint sensor 2 may be used to process a capacitive signal, which may represent the collected fingerprint image data.

[0030] like Figure 1 As shown, the packaging test system 1 may include a test board 11 and a test machine 10 for placing the capacitive fingerprint sensor 2. The test machine 10 may be connected to the test board 11 for communication.

[0031] In some embodiments, Figure 2 As shown, the capacitive fingerprint sensor 2 may include a substrate 23, a chip 21, a plastic layer 20 and a lead 22. The chip 21 may be disposed on the substrate 23 and connected to the substrate 23 via the lead 22. The chip 21 and the surroundings of the substrate 23 may be formed into a plastic layer 20 by injection molding to complete the encapsulation of the capacitive fingerprint sensor 2. When abutting against the outer surface of the plastic layer 20, the capacitive fingerprint sensor 2 may collect image data.

[0032] In some embodiments, the test machine 10 may include a conductive rubber head 103 and a switch control circuit 102 for controlling the conductive rubber head 103 to be grounded.

[0033] In some embodiments, Figure 3 As shown, the switch control circuit 102 may include a switch element SW1, a first resistor R1, a second resistor R2, a diode D1, and a transistor Q1. The base of the transistor Q1 may be connected to one end of the first resistor R1 and one end of the second resistor R2, wherein the other end of the first resistor R1 is connected to the port SW_IO, and the port SW_IO is used to receive a switch control command of the test machine 10; the emitter of the transistor Q1 may be connected to the other end of the second resistor R2 and grounded; the collector of the transistor Q1 may be connected to the first end of the switch element SW1 and the anode of the diode D1, wherein the cathode of the diode D1 is connected to the fourth end of the switch element SW1 and connected to the power supply voltage.

[0034] In some embodiments, the second end of the switch element SW1 may be grounded, and the third end of the switch element SW1 may be connected to the port PIN_1 , ie, to the conductive rubber head 103 , wherein a switch is connected between the second and third ends of the switch element SW1 .

[0035] In some embodiments, the test board 11 may include a display screen 110 and a main control chip 111 ; the display screen 110 may be used to display the test results; and the main control chip 111 may be used to send control instructions to the test machine 10 .

[0036] In some embodiments, the conductive rubber head 103 can be used to test the capacitive fingerprint sensor 2. When the conductive rubber head 103 abuts against the outer surface of the plastic layer 20 of the capacitive fingerprint sensor 2, the conductive rubber head 103 can apply pressure to the capacitive fingerprint sensor 2, and the chip 21 in the capacitive fingerprint sensor 2 can collect image data of the conductive rubber head 103 and obtain fingerprint signal quantity parameters at the same time.

[0037] In some embodiments, the test machine 10 may include a PCB (Printed Circuit Board) carrier 100 and a socket 101. The socket 101 may be provided with a plurality of socket contacts connected to the chip of the capacitive fingerprint sensor 2, and the socket 101 connects the chip pins of the capacitive fingerprint sensor 2 to the PCB carrier 100 through a plurality of probes. In some embodiments, the conductive rubber head 103 may be connected to the PCB carrier 100 through a wire.

[0038] In some embodiments, the PCB carrier 100 may include a connector J1, and the connector J1 may be connected to both the main control chip 111 and the switch control circuit 102. Figure 4 As shown, the second port of the connector J1 can be connected to the port SW_IO of the switch control circuit 102, the fourth port of the connector J1 can be connected to the port SCLK of the main control chip 111, the fifth port of the connector J1 can be connected to the port NSS of the main control chip 111, the sixth port of the connector J1 can be connected to the port MOSI of the main control chip 111, the seventh port of the connector J1 can be connected to the port MISO of the main control chip 111, the eighth port of the connector J1 can be connected to the port INT of the main control chip 111, and the ninth port of the connector J1 can be connected to the port RSTN of the main control chip 111. Among them, the port SCLK can be used to transmit a serial clock signal, the port NSS can be used to transmit a chip selection signal, the port MOSI can be used to transmit a signal transmitted from the main control chip 111 to the PCB carrier 100, the port MISO can be used to transmit a signal transmitted from the PCB carrier 100 to the main control chip 111, the port INT can be used to transmit an interrupt signal, and the port RSTN can be used to transmit a reset signal.

[0039] In some embodiments, the PCB carrier 100 may include a socket pad U1, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first TVS tube D2, a second TVS tube D3, and a third TVS tube D4. Figure 5 As shown, the first port of the socket pad U1 can be connected to the port NSS of the main control chip 111, the second port of the socket pad U1 can be connected to the port SCLK of the main control chip 111, the third port of the socket pad U1 can be connected to the port MISO of the main control chip 111, the fifth port of the socket pad U1 can be connected to the port MOSI of the main control chip 111, the nineteenth port of the socket pad U1 can be connected to the port RSTN of the main control chip 111, and the twentieth port of the socket pad U1 can be connected to the port INT of the main control chip 111. The twelfth port of the socket pad U1 can be connected to one end of the second capacitor C2, and the eleventh port of the socket pad U1 can be connected to the other end of the second capacitor C2 and the anode of the second TVS tube D3, wherein the cathode of the second TVS tube D3 is grounded. The eighteenth port of the socket pad U1 can be connected to one end of the third capacitor C3, the cathode of the third TVS tube D4, one end of the first capacitor C1 and the first TVS tube D2, and grounded; the fourteenth port of the socket pad U1 can be connected to the other end of the third capacitor C3 and the anode of the third TVS tube D4. The seventh port, the sixteenth port and the seventeenth port of the socket pad U1 can be connected to one end of the first capacitor C1 and the anode of the first TVS tube D2, respectively, and connected to the power supply voltage. The socket 101 can be connected to the socket pad U1.

[0040] In some embodiments, Figure 1 As shown, the test machine 10 may include a mechanical arm 104. The mechanical arm 104 may be used to drive the conductive rubber head 103 to be pressed down or lifted, so that the conductive rubber head 103 is close to or away from the outer surface of the plastic packaging layer 20. The mechanical arm 104 may face the socket 101.

[0041] In some embodiments, the test board 11 can control the mechanical arm 104 to move in a direction close to or away from the socket 101 , so that the mechanical arm 104 drives the conductive rubber head 103 to move together.

[0042] In some embodiments, Figure 6 As shown, the test machine 10 may include a clamping portion 105 and an elastic component 106. The clamping portion 105 and the elastic component 106 may be disposed in an inner cavity extending inwardly from the mechanical arm 104, one end of the elastic component 106 may be connected to the bottom of the inner cavity, the other end of the elastic component 106 may be connected to one end of the clamping portion 105, and the other end of the clamping portion 105 may clamp the conductive rubber head 103.

[0043] In some embodiments, one end of the conductive rubber head 103 can be engaged with the other end of the clamping portion 105, and the other end of the conductive rubber head 103 can be used to abut against the outer surface of the plastic layer 20. The clamping portion 105 can be an insulating clamp. Thus, environmental interference by the test machine 10 can be avoided.

[0044] In some embodiments, the elastic component 106 may be a spring or an elastic diaphragm.

[0045] In some embodiments, the test board 11 can send a control instruction to the test machine 10, so that the test machine 10 drives the conductive rubber head 103 to abut against the outer surface of the plastic layer 20 of the capacitive fingerprint sensor 2. The test board 11 can control the capacitive fingerprint sensor 2 to obtain the first fingerprint signal quantity parameter corresponding to the conductive rubber head 103 when the switch control circuit 102 is disconnected.

[0046] In some embodiments, the test board 11 can control the switch control circuit 102 of the test machine 10 to close so that the conductive rubber head 103 is grounded, and the test board 11 can control the capacitive fingerprint sensor 2 to obtain the second fingerprint signal quantity parameter corresponding to the conductive rubber head 103. When the switch control circuit 102 is closed, the conductive rubber head 103 can be grounded; when the switch control circuit 102 is disconnected, the conductive rubber head 103 can be in an ungrounded state.

[0047] In some embodiments, the test board 11 may write a sensor internal circuit gain parameter (DACP) into a register of the capacitive fingerprint sensor 2 , and the sensor internal circuit gain parameter may remain unchanged when acquiring the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter.

[0048] In some embodiments, the test board 11 can control the mechanical arm 104 to press down, so that the conductive rubber head 103 is in contact with the outer surface of the plastic layer 20, and then write the sensor internal circuit gain parameter into the register of the capacitive fingerprint sensor 2, and control the capacitive fingerprint sensor 2 to perform a map acquisition operation to obtain the first fingerprint signal quantity parameter corresponding to the conductive rubber head 103, at which time the switch control circuit 102 is in a disconnected state; then, the test board 11 can control the switch control circuit 102 to close, so that the conductive rubber head 103 is grounded, and obtain the second fingerprint signal quantity parameter corresponding to the conductive rubber head 103, at which time the sensor internal circuit gain parameter of the capacitive fingerprint sensor 2 remains unchanged.

[0049] In some embodiments, the sensor internal circuit gain parameter can be written after the pressure value generated by the conductive rubber head 103 abutting against the outer surface of the plastic layer 20 of the capacitive fingerprint sensor 2 remains stable.

[0050] In some embodiments, the test board 11 can determine whether the package gap of the capacitive fingerprint sensor 2 meets the package requirements based on the first fingerprint signal parameter and the second fingerprint signal parameter. The test board 11 can make the determination based on the difference between the first fingerprint signal parameter and the second fingerprint signal parameter.

[0051] In some embodiments, when the conductive rubber head 103 is not grounded, the capacitance value C1 detected by the fingerprint sensing array satisfies the following formula:

[0052] C1=C Rubber ,

[0053] Among them, C Rubber is the capacitance value of the conductive rubber head 103 .

[0054] In some embodiments, when the conductive rubber head 103 is grounded, the capacitance value C2 detected by the fingerprint sensing array satisfies the following formula:

[0055] C2=C Rubber +C Ground ,

[0056] Among them, from the capacitance formula C=εS / 4πkd, it can be seen that when C Ground The smaller the distance d is, the larger the distance d is. Therefore, the distance d can be equivalent to the packaging gap of the capacitive fingerprint sensor 2.

[0057] In some embodiments, the first fingerprint signal parameter may have a conversion relationship with the capacitance value C1 detected by the fingerprint sensing array; correspondingly, the second fingerprint signal parameter may have a conversion relationship with the capacitance value C2 detected by the fingerprint sensing array.

[0058] In some embodiments, the fingerprint sensing array may include a plurality of capacitive fingerprint sensors 2 .

[0059] The corresponding relationship between the fingerprint signal parameters and the package gap involved in this application is shown in Table 1 and Table 2:

[0060] Table 1

[0061]

[0062] Table 2

[0063]

[0064] The fingerprint signal quantity parameters in Table 1 and Table 2 are obtained by testing a capacitive fingerprint sensor 2 with a standard package gap. It can be seen from Table 1 and Table 2 that the package gap and the fingerprint signal quantity parameters may have a corresponding relationship, and as shown in the data in the table, the smaller the fingerprint signal quantity parameter is, the larger the package gap is.

[0065] For example, when testing a capacitive fingerprint sensor 2 with a package gap of 55 microns, if the obtained fingerprint signal difference is not within the range of 105 by 5% to 10%, it can be considered that the package of the capacitive fingerprint sensor 2 is unqualified. For example, when the floating value is set to 5%, if the range of the obtained fingerprint signal difference is not within the range of [99.75, 110.25], it can be considered that the package of the capacitive fingerprint sensor 2 with a package gap of 55 microns is unqualified.

[0066] The present application also relates to a packaging testing method, which may include the following steps:

[0067] The test board 11 sends control instructions to the test machine 10;

[0068] After the test machine 10 receives the control command, the test machine 10 drives the conductive rubber head 103 to contact the outer surface of the plastic packaging layer 20 of the capacitive fingerprint sensor 2 on the test machine 10, and the capacitive fingerprint sensor 2 obtains the first fingerprint signal quantity parameter corresponding to the conductive rubber head 103 when the switch control circuit 102 is disconnected;

[0069] The test board 11 controls the switch control circuit 102 of the test machine 10 to close so that the conductive rubber head 103 is grounded, and the capacitive fingerprint sensor 2 obtains the second fingerprint signal quantity parameter corresponding to the conductive rubber head 103;

[0070] The test board 11 determines whether the packaging gap of the capacitive fingerprint sensor 2 meets the packaging requirements according to the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter.

[0071] In the present application, the conductive rubber head 103 is driven to contact the outer surface of the plastic layer 20 of the capacitive fingerprint sensor 2, and the first fingerprint signal quantity parameter corresponding to the conductive rubber head 103 is obtained when the switch control circuit 102 is disconnected; at the same time, the conductive rubber head 103 is grounded by controlling the switch control circuit 102 to close, and the second fingerprint signal quantity parameter corresponding to the conductive rubber head 103 is obtained, and the package gap is judged whether it meets the package requirements according to the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter. In this case, since the fingerprint signal quantity parameter of the capacitive fingerprint sensor 2 is related to the capacitance change, it will be affected by multiple factors including the package gap. The present application tests the package gap by capturing the fingerprint signal quantity parameter change when the conductive rubber head 103 is grounded and not grounded, that is, a single variable, which can better exclude other factors, such as the influence of the downward pressure, so that the test result of the package gap is more accurate. At the same time, it can reduce the damage or loss of the capacitive fingerprint sensor 2 due to the test, and is more suitable for the comprehensive test of the capacitive fingerprint sensor 2.

[0072] Those skilled in the art can understand that all or part of the features / steps of the above-mentioned method embodiments can be implemented by methods, data processing systems or computer programs, and these features can be implemented without hardware, entirely by software, or by a combination of hardware and software. The aforementioned computer program can be stored in one or more computer-readable storage media, and the storage medium stores the computer program. When the computer program is executed (such as by a processor), the steps of the above-mentioned packaging test method embodiments are executed.

[0073] The aforementioned storage media that can store program codes include: static hard disks, solid-state hard disks, random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), optical storage devices, magnetic storage devices, flash memory, magnetic disks or optical disks and / or combinations of the above devices, that is, they can be implemented by any type of volatile or non-volatile storage device or a combination thereof.

[0074] The present application also provides an embodiment of a processing device, comprising one or more processors and a memory; wherein the memory is used to store one or more computer programs, and the one or more processors are used to execute one or more computer programs stored in the memory, so that the processor performs the features / steps of the above-mentioned packaging test method embodiment.

[0075] The above is only the preferred embodiment of the present application. Those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present application. In addition, under the guidance of the present application, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application belong to the protection scope of the present application.

Claims

1. A packaging test system for a capacitive fingerprint sensor, characterized in that: The packaging test system is used to test the packaging gap of the capacitive fingerprint sensor, the capacitive fingerprint sensor includes a chip and a plastic packaging layer for packaging the chip, the packaging gap is the distance between the surface of the chip and the inner surface of the plastic packaging layer, the packaging test system includes a test board and a test machine for placing the capacitive fingerprint sensor; the test machine is communicatively connected with the test board; The testing machine comprises a conductive rubber head and a switch control circuit for controlling the grounding of the conductive rubber head; The capacitive fingerprint sensor is placed on the test machine, and the test board sends a control instruction to the test machine, so that the test machine drives the conductive rubber head to abut against the outer surface of the plastic sealing layer of the capacitive fingerprint sensor, and the test board controls the capacitive fingerprint sensor to obtain the first fingerprint signal quantity parameter corresponding to the conductive rubber head when the switch control circuit is disconnected; The test board controls the switch control circuit of the test machine to close so that the conductive rubber head is grounded, and the test board controls the capacitive fingerprint sensor to obtain a second fingerprint signal parameter corresponding to the conductive rubber head; The test board determines whether the packaging gap of the capacitive fingerprint sensor meets the packaging requirements according to the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter; the test machine includes a PCB carrier and a socket; the socket is provided with a plurality of socket contacts connected to the chip of the capacitive fingerprint sensor, and the socket connects the chip pins of the capacitive fingerprint sensor to the PCB carrier through a plurality of probes; the test board includes a display screen and a main control chip; the display screen is used to display the test results; the main control chip is used to send the control instruction to the test machine; the PCB carrier includes a connector J1, and the connector J1 is connected to both the main control chip and the switch control circuit; the connector The second port of the connector J1 is connected to the port SW_IO of the switch control circuit, the fourth port of the connector J1 is connected to the port SCLK of the main control chip, the fifth port of the connector J1 is connected to the port NSS of the main control chip, the sixth port of the connector J1 is connected to the port MOSI of the main control chip, the seventh port of the connector J1 is connected to the port MISO of the main control chip, the eighth port of the connector J1 is connected to the port INT of the main control chip, and the ninth port of the connector J1 is connected to the port RSTN of the main control chip; the PCB carrier includes a socket pad U1, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first TVS tube D2, a second TVS tube D3 and a third TVS tube D4; the first port of the socket pad U1 is connected to the port NSS of the main control chip, the second port of the socket pad U1 is connected to the port SCLK of the main control chip, the third port of the socket pad U1 is connected to the port MISO of the main control chip, the fifth port of the socket pad U1 is connected to the port MOSI of the main control chip, the nineteenth port of the socket pad U1 is connected to the port RSTN of the main control chip, and the twentieth port of the socket pad U1 is connected to the port INT of the main control chip; the twelfth port of the socket pad U1 is connected to one end of the second capacitor C2, and the tenth port of the socket pad U1 is connected to the port MISO of the main control chip. A port is connected to the other end of the second capacitor C2 and the anode of the second TVS tube D3, wherein the cathode of the second TVS tube D3 is grounded; the eighteenth port of the socket pad U1 is connected to one end of the third capacitor C3, the cathode of the third TVS tube D4, one end of the first capacitor C1 and the cathode of the first TVS tube D2, and is grounded; the fourteenth port of the socket pad U1 is connected to the other end of the third capacitor C3 and the anode of the third TVS tube D4; the seventh port, the sixteenth port and the seventeenth port of the socket pad U1 are respectively connected to the other end of the first capacitor C1 and the anode of the first TVS tube D2, and are connected to the power supply voltage.

2. The packaging and testing system for a capacitive fingerprint sensor according to claim 1, characterized in that: The testing machine comprises a mechanical arm; the mechanical arm is used to drive the conductive rubber head to be pressed down or lifted up, so that the conductive rubber head is close to or away from the outer surface of the plastic packaging layer.

3. The packaging and testing system for a capacitive fingerprint sensor according to claim 2, characterized in that: The testing machine includes a clamping part and an elastic component; the clamping part and the elastic component are arranged in an inner cavity extending inwardly from the mechanical arm, one end of the elastic component is connected to the bottom of the inner cavity, the other end of the elastic component is connected to one end of the clamping part, and the other end of the clamping part clamps the conductive rubber head.

4. The packaging and testing system for a capacitive fingerprint sensor according to claim 1, characterized in that: The test board writes a sensor internal circuit gain parameter into a register of the capacitive fingerprint sensor, and the sensor internal circuit gain parameter remains unchanged when the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter are obtained.

5. The packaging and testing system for a capacitive fingerprint sensor according to claim 1, characterized in that: The switch control circuit includes a switch element SW1, a first resistor R1, a second resistor R2, a diode D1 and a transistor Q1; the base of the transistor Q1 is connected to one end of the first resistor R1 and one end of the second resistor R2, wherein the other end of the first resistor R1 is connected to a port SW_IO, and the port SW_IO is used to receive a switch control command of the test machine; the emitter of the transistor Q1 is connected to the other end of the second resistor R2 and is grounded; the collector of the transistor Q1 is connected to the first end of the switch element SW1 and the anode of the diode D1, wherein the cathode of the diode D1 is connected to the fourth end of the switch element SW1 and is connected to a power supply voltage; the second end of the switch element SW1 is grounded, and the third end of the switch element SW1 is connected to the conductive rubber head, wherein a switch is connected between the second end and the third end of the switch element SW1.

6. A packaging test method, characterized in that: The packaging test method is used in the packaging test system according to any one of claims 1 to 5, comprising the following steps: The test board sends control instructions to the test machine; After the test machine receives the control instruction, the test machine drives the conductive rubber head to contact the outer surface of the plastic sealing layer of the capacitive fingerprint sensor on the test machine, and the capacitive fingerprint sensor obtains the first fingerprint signal quantity parameter corresponding to the conductive rubber head when the switch control circuit is disconnected; The test board controls the switch control circuit of the test machine to close so that the conductive rubber head is grounded, and the capacitive fingerprint sensor obtains a second fingerprint signal parameter corresponding to the conductive rubber head; The test board determines whether the packaging gap of the capacitive fingerprint sensor meets the packaging requirements according to the first fingerprint signal quantity parameter and the second fingerprint signal quantity parameter.

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