Optical sensor ATE test method based on multiple excitation environments

Abstract

The invention discloses an optical sensor ATE test method based on multiple excitation environments, and the method specifically comprises the steps: transmitting a chip to a fixed test station through a Handler structure, building the electrical connection between the chip and a test machine through a special PCB and a spring needle, building the GPIB communication through a chip test machine, and enabling the chip test machine to carry out the GPIB communication. Communication is carried out between the Handler and the Tester, so that a test machine sends a command to enable the Handler to establish ALS (ambient light), PS (proximity light) and CT (crosstalk) excitation environments and realize switching among different excitation environments during ALS light source test, PS grey card test and CT hollow cover plate test processes, and thus the complete coverage test process of the direct current parameters and functions of the light sensing chip is realized. Wherein the test machine is responsible for realizing execution of a test program and output of test data, and the handler is responsible for realizing action operation of test hardware. Three excitation environment hardware and three sets of programs are integrated in one set of test system, so that the test time is optimized, the test efficiency is improved, the equipment investment is reduced, and the system is flexible and efficient.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor chip testing, and in particular relates to an optical sensor ATE testing method based on a multi-stimulus environment. Background Art

[0002] With the rapid development of my country's chip semiconductor industry in recent years, semiconductor testing, as an important link from chip design to factory delivery, is also playing an increasingly important role in the entire chip industry chain. Semiconductor testing is responsible for verifying chip design, function implementation, screening and grading, capability assessment, storage and packaging, etc. However, optical sensor testing based on analog-digital hybrid has not been mature and industrialized on a large scale in the current semiconductor packaging and testing field, and most of the references and experience come from foreign companies.

[0003] The test time and test complexity of optical sensors are relatively high. The commonly used test solutions currently require complex and large-scale customized equipment or use multiple running equipment to test items in series to fully cover the test requirements, which has low test efficiency and high costs. At the same time, due to the large number of product subdivisions and the lack of compatibility of existing equipment, it is often necessary to switch or expand related hardware and software, which also consumes a lot of resources to a certain extent. It is necessary to improve a low-cost test method with high coverage, high accuracy and high efficiency on the existing basis. Summary of the invention

[0004] The purpose of the present invention is to propose an optical sensor ATE test method based on multiple excitation environments to achieve efficient production testing of photosensor chips, realize parallel testing of multiple excitation environments through fixed workstations, maximize the use of test resources to achieve a higher test coverage, and be compatible with the testing requirements of multiple product categories.

[0005] The technical solution of the present invention is: an optical sensor ATE test method based on a multi-stimulus environment, including a chip tester (Tester), which is used to test the function of the chip, provide an optical stimulus environment source, run the chip test program and output the test results and data; a handler (Handler), which is used to mechanically transport, fix, establish the test environment and sort and package the product for the chip module. In order to achieve the above technical solution adopted by the present invention is:

[0006] The first aspect proposes a register read and write operation method based on the I2C communication protocol:

[0007] Step 1: When you want to write to a register, you need to write the pattern according to the protocol, that is, the start signal, device address, write command, ACK, register address, data, ACK, stop signal. Complete the register write operation in the above way.

[0008] Step 2: Since the device address is always fixed, the register address and data are defined as int input variables: register and data through a function. The function converts int register and int data into 16-bit binary data respectively, that is, the required register address and data are obtained.

[0009] Step 3: Write the data obtained in step 2 to the corresponding position of the pattern. The Tester can run the pattern to implement the write operation command for all registers of the chip;

[0010] Step 4: For I2C read operation, you need to write pattern according to the protocol, that is, start signal, device address, write command, ACK, register address, ACK, device address, read command, ACK, data, NACK, stop signal;

[0011] Step 5: Define the register address and data as int input variables: register and data, convert intregister and int data into 16-bit binary data. Since this is a register read operation, convert the binary data of data into H or L according to the result of 0 or 1.

[0012] Step 6: Write the data in step 5 to the corresponding position of the pattern. The Tester can read all registers of the chip by running the pattern.

[0013] The second aspect provides a method for GPIB communication to enable the handler to control the hardware switching of the three stimulus environments ALS, PS and CT through program operation during the test. In the complete light sensing chip test, in addition to the basic DC electrical test, optical performance index tests such as ALS test, PS test and CT test are also required. The three test switching implementation methods are as follows:

[0014] (1) The ATE test program contains all the test items of the chip, which are executed in sequence during the test;

[0015] (2) When ATE runs to the ALS test, it executes the GPIBWRITE function and writes the "LIGHTON" instruction into the GPIB data;

[0016] (3) Call the function GET_GPIB_iberr to obtain the GPIB data communication status information and confirm whether the GPIB communication is normal. If the result is 0, the communication is normal; if the result is not 0, the communication is abnormal.

[0017] (4) When communication is normal, send a GPIB communication request;

[0018] (5) Check whether the GPIB request address is consistent with the preset address. If it is correct, the communication is completed. If it is not correct, it will be executed again.

[0019] (6) The Handler starts the motor according to the received command and moves the light source to the preset position;

[0020] (7) After waiting for a fixed delay, the test program controls the ATE device through code to apply a predefined voltage to the light source, the light source works, and the ALS test process automatically starts;

[0021] (8) After the ALS test is completed, the PS test is performed. The GPIBWRITE function is executed, and the "CYLGO" command is sent to write the GPIB communication data. Steps (3) to (5) are executed. The Handler receives the command, starts the motor, removes the light source barrel, and moves the gray card to the top of the chip. After a fixed delay of 500ms, the ATE performs the PS test.

[0022] (9) After the PS test is completed, the CT test is performed, the GPIBWRITE function is executed, the "CYLBACK" command is sent to write the GPIB communication data, and steps (3)-(5) are executed. The Handler receives the command, starts the motor, removes the gray card chip, and waits for a fixed delay before the ATE performs the CT test;

[0023] (10) After the chip testing process is completed, a new chip enters the workstation and steps (1) to (10) are executed again.

[0024] In a third aspect, the present invention further proposes a device that meets the requirements of multi-stimulus environment testing, including: a stepper motor and a screw; a translation bracket; a light source barrel with adjustable illumination and height; and a gray card with adjustable height.

[0025] Specifically, the stepper motor is driven by the host control of the handler. The instructions come from ATE via GPIB. When the program runs to the specified process, the stepper motor working instructions are triggered.

[0026] ALS test, PS test and CT will move different distances according to the position of the chip on the workstation to ensure that the stimulus environment is placed directly above the chip.

[0027] The precise movement of the stepper motor can be controlled parameterized by inputting the corresponding parameters into the handler control software according to the relative positions of the light source and the gray card on the bracket.

[0028] The present invention adopts the above technical solution, and compared with the prior art, its significant technical effects are as follows:

[0029] (1) The present invention implements three stimulus environment tests at one station and integrates three tests together. Compared with the previous situation where three devices and three sets of programs are used to test three environments, the investment of test resources is reduced and the test cost is saved;

[0030] (2) The present invention uses a set of procedures to completely cover the testing requirements of the product, reducing the product yield loss caused by product turnover and repeated testing.

[0031] (3) In the chip testing process of the present invention, the hardware environment is relatively fixed, which reduces the test instability caused by equipment and hardware changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall architecture of the present invention.

[0033] Figure 2 It is a schematic diagram of I2C communication write command in the present invention.

[0034] Figure 3 It is a data structure diagram of the I2C communication write command in the present invention.

[0035] Figure 4 It is a data structure diagram of the I2C communication read command in the present invention.

[0036] Figure 5 It is a schematic diagram of the I2C write operation pattern in the present invention.

[0037] Figure 6 It is a schematic diagram of a device for testing a photosensitive chip in a multi-stimulus environment in the present invention. DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0039] Embodiment 1: A chip register read and write operation method based on the I2C communication protocol specifically includes the following: defining the chip pins SDA and SCL as IO channels in the ATE tester to indicate that this channel can perform digital input and output; defining the I2C clock rate as 400kHz, the period as 1 / 400kHz, i.e. 2.5us, and half a period as 1.25s; to implement a write operation on a register, it is necessary to write a pattern according to the protocol, i.e., a start signal, a device address, a write command, ACK, a register address, data, ACK, and a stop signal. Since the device address is always fixed, the register address and data are defined as input variables: register and data through a function. The function converts register and data into 16-bit binary data respectively, i.e., the required register address and data are obtained; the obtained data is written into the corresponding position of the pattern, and the Tester runs the pattern to implement the write operation on all registers of the chip, such as the function I2C_WRITE (0x00, 0x05), where the register address is 0x00 and the written data should be 0x05. For I2C read operations, you need to write a pattern according to the protocol, namely, start signal, device address, write command, ACK, register address, ACK, device address, read command, ACK, data, NACK, and stop signal; define the register address and data as input variables: register and data, convert register and data into 16-bit binary data. Since this is a register read operation, convert the binary data of data to H or L according to the result of 0 or 1; write the data in step 5 to the corresponding position of the pattern, and the Tester can run the pattern to realize the read operation of all registers of the chip, such as I2C_READ (0x00, 0x06), where the register address is 0x00 and the read data should be 0x06.

[0040] Embodiment 2: Based on the chip register fast read and write operation method based on the I2C communication protocol of embodiment 1, this embodiment provides an optical sensor test device with multiple excitation environments. It includes a stepper motor for realizing translation of the driving device, a screw for realizing precise distance translation, a translation bracket for carrying the excitation environment, a light source barrel with adjustable illumination and height, and a gray card with adjustable height.

[0041] First, the Handler runs and transfers the chip to the station to be tested, and sends the SOT signal through GPIB; the Tester receives the SOT signal and runs the entire set of composite test programs; when the program flow runs to the ALS program, the GPIB communication program is executed, and instructions are sent to the handler to move the light source to prepare the ALS test environment; at this time, the stepper motor drives the bracket to move the light source directly above the chip, completes the action and waits for a fixed delay; the Tester runs the ALS test program. If the test result fails, the test at this station stops, and the Tester sends the binning information to the Handler through GPIB. If the test result passes, the PS test program is ready to be executed, and the Handler sends instructions to the Handler through GPIB; at this time, the stepper motor drives the bracket to translate to make the gray card Located directly above the chip, after completing the action and waiting for a fixed delay; the Tester runs the PS test program. If the test result fails, the test is stopped at this station. The Tester sends the binning information to the Handler via GPIB. If the test result passes, the CT test program is ready to be executed. The Handler sends instructions to the Handler via GPIB. At this time, the stepper motor drives the bracket to translate so that there is no obstruction directly above the chip. After completing the action and waiting for a fixed delay; the Tester runs the CT test program. At this time, the whole program ends, and the information is sent to the handler according to the pass or fail test result: the Handler moves the chip to the fixed bin barrel or tape according to the binning information, and runs the stepper motor to restore the bracket to the initial position, waiting for the next round of test commands.

[0042] As mentioned above, when a chip enters a fixed test station, the three stimulus environments can be tested through the cooperation of hardware and programs. There is no need to place the chip in a fixed environment for testing and then transfer it, which saves more test time and improves test efficiency. At the same time, for some specific light-sensing chips, if only one of the three stimulus environments of ALS, PS, and CT needs to be tested, the test items and execution logic can be modified according to the needs, so as to realize the test for the specified stimulus environment, which is flexible and adaptable.

[0043] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. An optical sensor ATE test method based on multiple stimulus environments, characterized in that: Including ATE test system, GPIB communication module and multi-stimulus environment hardware device; The ATE test system is mainly composed of ATE hardware language, test algorithms and ATE test equipment hardware. It is responsible for implementing tests on relevant performance parameters and electrical indicators of the chip. At the same time, it generates standard test data and logs based on software editing to realize digital representation and analysis and optimization of the test results.

2. The optical sensor ATE test method based on multiple excitation environments according to claim 1 is characterized in that: A fast chip testing method based on I2C communication is proposed. In order to realize the chip functional test based on the I2C communication protocol, the standard I2C write protocol and I2C read protocol are implemented through ATE test pattern to realize dynamic read and write operations, which can achieve the goal of fast and flexible register testing. The specific method is as follows: In the I2C protocol, each byte sent to SDA must be 8 bits. The bytes transmitted each time are not limited. Each byte must be followed by an ACK response bit. The data transmission order is from MSB to LSB. The data bit SDA is only valid when SCL is high and invalid at low level. Therefore, in order to realize the clock cycle, the pattern splits each bit into two bits. Step 1: Define the chip pins SDA and SCL as IO channels in ATE to indicate that this channel can perform digital input and output; Step 2: Define the I2C clock rate as 400kHz in ATE, the period as 1 / 400kHz, 2.5us, and half a period is 1.25s; Step 3: When writing to a register, you need to write a pattern according to the protocol, that is, the start signal, device address (0x55), write command, ACK, register address, data, ACK, stop signal, and then the write operation of a register is completed; Step 4: Since the device address is always fixed, the register address and data are defined as int input variables: register and data through the function. The function will convert int register and int data into 16-bit binary data (expand 1 byte of 8 bits to 16 bits according to the complete clock cycle), that is, get the required register address and data. The specific method is as follows: Register address: bit[8] Then copy each element of bit[8] and add one bit to obtain 16-bit pattern data. The data also obtains 16-bit pattern data according to this algorithm. Step 5: Write the data obtained in step 4 into the register address and data position corresponding to the pattern. Tester runs the pattern to implement the write operation on the chip register. Step 6: For I2C read operation, you need to write pattern according to the protocol, that is, start signal, device address, write command, ACK, register address, ACK, device address, read command, ACK, data, NACK, stop signal; Step 7: Define the register address and data as int input variables: register and data, and convert int register and int data into 16-bit binary data according to the method in step 4. Since this is a register read operation, the binary data of data is converted to H or L according to the result of 0 or 1; Step 8: Write the data in step 7 to the corresponding position of the pattern. Tester runs the pattern to read the chip register. Step 9: Define two general functions with input variables for reading registers and writing registers to implement operations on all registers during light sensor chip testing and implement test chip related parameters. The above process can realize fast reading and writing operations on the chip registers during light sensing testing, reducing the repetitive work of designing patterns for each register operation separately, and greatly improving reusability and convenience.

3. The optical sensor ATE test method based on multiple excitation environments according to claim 1, characterized in that: The three different stimulus environment tests of the optical sensor are combined into a set of composite program tests. The contents are: Step 1: Before running the ALS test program, run the GPIB communication program and send instructions to the handler to move the light source and prepare the ALS test environment: Step 2: ATE runs the ALS test program; if the ALS test is completed and passed, the GPIB communication program is run to remove the light source. If the ALS test result fails, the tester sends the binning information to the handler through the GPIB command; Step 3: ATE runs the PS test program. If the PS test is completed and passed, the GPIB communication program is run to remove the gray card. If the PS test fails, the tester sends the binning information to the handler through GPIB instructions. Step 4: ATE runs the CT test program. If the CT test is completed and passed, the GPIB communication program is run to reset the bracket and wait for a new round of testing of the next product. If the CT test fails, the tester sends the binning information to the handler through GPIB instructions. According to the above process, a set of composite program tests for switching between three stimulus environments is implemented.

4. The optical sensor ATE test method based on multiple excitation environments according to claim 1, characterized in that: The stimulus environment is switched through the GPIB communication command between the test machine and the handler. When the test program executes to the ALS test, the ATE executes the function Light_cover(). At this time, the function will send the instruction of moving the light source to the Handler through GPIB communication. The specific content is: (1) Use the GPIBWRITE function in the GPIB driver GPIB Vis to write the instruction "LIGHTON" into the GPIB data; (2) Use the function GET_GPIB_iberr to obtain GPIB data confirmation information to confirm whether the GPIB communication is normal. If the result is 0, the communication is normal. If the result is not 0, the communication is abnormal. (3) Send GPIB communication request; (4) Check if the GPIB request address is consistent with the preset address. If it is correct, pass and the communication is completed. (5) The Handler starts the motor according to the received command and moves the light source to the preset position; (6) The test program controls the ATE device through code to apply a predefined voltage to the light source, the light source works, and the ALS test process automatically starts. In the PS test and the CT test, when the corresponding test items are executed, the switching of the stimulus environment is also realized according to the above (1)-(6) process. The command distribution of the PS test and the CT test is defined as "CYLGO" and "CYLBACK" and transmitted to the Handler through GPIB. Since the light source used in the ALS test, the gray card used in the PS test, and the light leakage hole used in the CT test are all installed on a mechanical structure bracket driven by the motor, it is only necessary to preset the three sets of distance parameters of the motor movement to: 1200, 800 and 100 respectively.

5. The optical sensor ATE test method based on multiple excitation environments according to claim 1, characterized in that: Three excitation environment devices driven by motors include the following structures: The stepper motor is used to drive the bracket; the screw is used to transmit the stepper motor drive to the bracket to achieve translation; the bracket is used to load three types of excitation environments; the light source barrel equipped with LED is used to provide ALS test excitation; the flat gray card structure is used to provide PS test excitation; and the cover plate with light leakage holes and the unobstructed environment above provide CT test excitation.

6. The optical sensor ATE test method based on multiple excitation environments according to claim 1, characterized in that: The working process of the device is as follows: (1) When the Handler receives the ALS test request sent by the Tester through GPIB, the stepper motor drives the screw to rotate, causing the bracket on the screw to move outward to the set position; (2) At this time, the light source barrel moves to the position directly above the chip. After waiting for a fixed delay of 500ms, the program opens the pre-configured light source power supply parameters, the light source works, and the ATE equipment performs ALS testing; (3) After the ALS test is completed, the Handler receives the PS test request, and the stepper motor drives the screw to rotate, causing the bracket to translate inward to the specified position. (4) At this time, the gray card moves to the top of the chip, and after a fixed delay of 500ms, the ATE equipment runs the program to start the PS test; (5) After the PS test is completed, the Handler receives the CT test request, and the stepper motor drives the screw to rotate, causing the bracket to move inward to the specified position; (6) At this time, there is no obstruction above the chip. After waiting for a fixed delay of 500ms, the ATE runs the test program to perform the CT test. The characteristics of this device are as follows: 1) Use a stepper motor to drive the bracket to move, which has fast running speed and high precision. Different hardware positions can be adjusted by modifying parameters; 2) The light source voltage can be adjusted flexibly by modifying the power supply parameters in the program according to the needs to meet the testing requirements of different products; 3) The height of the gray card is not fixed and can be adjusted up and down according to different product parameters and test indicators; 4) Integrating three stimulus environments into one test station can save test resources and test time and improve test efficiency.

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