Automatic test method for resistance characteristics of integrated circuit

Abstract

The invention relates to a method for automatically testing resistance characteristics of an integrated circuit, which is characterized by comprising the following steps of: 1) automatically testing a chip and a voltage stabilizer used by the integrated circuit at normal temperature and normal pressure, normal temperature and low pressure, low temperature and normal pressure and high temperature and normal pressure, and extracting corresponding data; and 2) carrying out resistance detection by adopting a mode of carrying out voltage test by powering up. And (3) inputting by adopting an Excel data table form, wherein single input or batch input can be realized. And 4) according to product technical index requirements, determining a compensation calculation target, and setting an intuitive target value. And 5) through the compensation circuit schematic diagram, the external resistance value meeting the output requirement is comprehensively calculated, the calculation is carried out in an iteration mode, and an optimal result is selected. The automatic calculation and compensation method has the advantages that automatic calculation and compensation can be carried out on the integrated circuit resistors in batches, the calculation and compensation efficiency is high, the compensation precision is high, and the production efficiency of the integrated circuit is improved.

Description

Technical Field

[0001] The invention belongs to the field of integrated circuit testing, and relates to an automatic testing system and a testing method for integrated circuit resistance characteristic testing. Background Art

[0002] Some thick-film hybrid integrated circuit products need to meet the output accuracy requirements within the full temperature range, which means that performance parameters such as temperature and sensitivity need to be compensated. In the processing technology, the output performance and power supply of the circuit product need to be tested to obtain the resistance of the four bridge arms of the circuit product and the internal voltage-stabilized power supply output under five environmental conditions, including high temperature, low temperature, normal temperature, and low pressure; and by continuously trying to gradually match the resistance value, the approximate range of the resistance value of the internal adjustable resistor is obtained, so that the output performance of the product is theoretically met. However, the current resistance matching is mainly manual welding resistance matching, and the mutual influence relationship between the resistance values ​​is also large, resulting in a large error in the final resistance value. In addition, the data is also collected manually. When reading and recording the display, the number of digits and time will be inconsistent. The error of manual data collection causes the matching resistance value to appear when the circuit simulation is performed. The output cannot meet the requirements, and it also cannot meet the subsequent process processing. Summary of the invention

[0003] The purpose of the present invention is to solve the defects of poor resistance matching and data acquisition accuracy in the prior art and to provide an automatic testing method for the resistance characteristics of an integrated circuit.

[0004] The technical solution adopted by the present invention is as follows: An automatic testing method for integrated circuit resistance characteristics, characterized by comprising the following steps: 1) Automatically test the chips and voltage regulators used in the integrated circuit at normal temperature and pressure, normal temperature and low pressure, low temperature and normal pressure, and high temperature and normal pressure, and extract the corresponding data; 2) Resistance detection is performed by powering on and performing voltage testing; 3) Input data in Excel form, either individually or in batches; 4) According to the product technical index requirements, determine the compensation calculation target and set the intuitive target value; 5) Comprehensively calculate the resistance value that meets the output requirements through the compensation circuit schematic; The calculation is carried out in an iterative manner to select the best result; 6) and use programming language to realize the calculation result of the compensation solution formula.

[0005] The advantages of the present invention are that it can automatically calculate and compensate batches of integrated circuit resistors, so that the calculation and compensation efficiency is high and the compensation accuracy is high, thereby improving the integrated circuit production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 This is the schematic diagram of integrated circuit chip resistance measurement; Figure 2 Collect schematic diagram for chip resistor; Figure 3 This is the schematic diagram of the chip external resistor structure; Figure 4 Software flow chart of the present invention; Figure 5 It is a schematic diagram of inputting Excel data in a table format according to the present invention.

[0007] Specific implementation method 1. Measurement of chip sensor resistance in integrated circuits Refer to the circuit principle Figure 1 The integrated circuit is a thick-film hybrid integrated circuit, which includes a voltage regulator chip, a sensor chip, a signal processing circuit, a resistor, a capacitor and other chips and devices and a voltage regulator. The sensor marked in the figure is the sensor chip. The output end of the voltage regulator is connected to the chip. The sensor chip has its own bridge resistor, which is the series resistor R11, R12, R13, and R14. The connection points J3-1, J3-2, J3-3, and J3-4 between the four resistors of the bridge are respectively connected to the external signal processor, and the signal processor outputs analog or digital signals.

[0008] The integrated circuit chip (sensor chip) is tested at room temperature and pressure, room temperature and low pressure, low temperature and normal pressure, and high temperature and normal pressure to extract the corresponding data. Specifically, when the thick film hybrid integrated circuit is powered by 5V input, the probes are inserted into the four measuring ends of the four resistors of the chip bridge, that is, Figure 1 J3-1, J3-2, J3-3, and J3-4 are shown in the figure, and the multimeter probe is used to touch the probe to measure the bridge resistance one by one using the ohm range. At the same time, the probe is also inserted into the P1-1 and P1-2 ports where the voltage regulator and the chip are connected, and the multimeter probe is used to touch the probe to measure the voltage. When the thick-film hybrid integrated circuit is powered by a 28V voltage stabilizer, the output voltage of the three-terminal voltage regulator and the resistance value of the four bridge arms of the sensor circuit chip are measured.

[0009] To extract resistance data, the existing technology uses a multimeter to directly detect resistance. The current applied by the multimeter when measuring resistance is very small. Lead resistance, contact resistance, and external interference all have an impact on the test results. The most obvious manifestation is that the displayed value is always changing, which is different from the current during actual operation. In other words, the test is a static result and cannot fully reflect the actual working status.

[0010] The present invention adopts the method of powering on and performing voltage testing to perform resistance detection. The principle is as follows Figure 2 As shown: According to the actual working current of the product, that is, the thick film integrated circuit, which is about 0.5mA, an excitation current of about 0.5mA is applied to the whole product, that is, the current on the resistors R11, R12, R13, and R14 is about 0.5mA. RO is not a resistor in the thick film hybrid integrated circuit, but an external resistor for resistance value collection. R0=1kΩ, VDD=5V are selected, which has the following advantages: 1) Apply voltage excitation according to the current of the actual working state of the product (i.e. thick film hybrid integrated circuit), which is consistent with the actual working state; 2) The multimeter voltage test input impedance is high, and the lead resistance and contact resistance will not affect the test; 3) The excitation applied during the test is larger, and the anti-interference ability is increased.

[0011] 2. Use Excel spreadsheet to input data, either individually or in batches.

[0012] Use a multimeter, turn on the voltage gear, and measure the voltage (VDD and ground) flowing through the bridge resistors RO, R13, R14, R11, and R12 in the thick film hybrid integrated circuit in the order of normal temperature and pressure, low temperature and pressure, high temperature and pressure, and normal temperature and low pressure when applying excitation, and record it as V. Measure the voltage flowing through R13, R14, R11, and R12 and record it as V1. Measure the voltage flowing through R14, R11, and R12 and record it as V2. Measure the voltage flowing through R11 and R12 and record it as V3. Measure the voltage flowing through R12 and record it as V4. Enter the data of the voltages V1, V2, V3, and V4 measured at normal temperature and pressure, low temperature and pressure, high temperature and pressure, and normal temperature and low pressure into the Excel data table, as shown in the figure below. Figure 5 shown.

[0013] 3. According to the input and output values ​​required by the technical indicators of thick-film hybrid integrated circuit products, determine the difference in the resistance compensation value of the sensor chip, that is, how much voltage is still missing and how much resistance is needed to assist in voltage division, so as to calculate the target.

[0014] 1. Set intuitive target values: normal pressure output: 3750mV, low temperature output: 3800mV, high temperature output: 3750mV, low voltage output: 1050mV, and allowable deviation: 50mV. The intuitive target value can be combined with the type of adhesive used in the process at that time, the conductivity, the influence of the resistance value on the resistance, and the environmental conditions, i.e., the pressure value at normal pressure, the temperature value at normal pressure, the pressure value at low pressure, and the temperature value at low pressure, to calculate the difference in the middle, and calculate the ratio of the pressure to the output voltage of the batch of thick-film hybrid integrated circuits based on the pressure value and the output voltage value. According to the test sample results and the ratio of the environmental pressure to the output voltage of the batch of thick-film hybrid integrated circuits, determine what the resistance compensation resistance value of the current production batch of thick-film hybrid integrated circuits should be, and make appropriate adjustments and compensation; 2. Calculate the compensation resistance of the chip bridge external resistor like Figure 3 As shown in the compensation circuit schematic diagram, resistor R2 is connected between bridge resistors R13 and R12, one end of resistor R4 is connected between R13 and resistor R2, and the other end of R4 is grounded; one end of resistors R5 and R3 is connected between resistors R11 and R14, the other end of resistor R5 is connected to the common end of resistors R2 and resistor R4, the other end of R3 is connected to VCC, resistor R6 is connected between resistors R13 and R14, the other end of resistor R6 is connected to one end of resistors R7 and R8, the other end of resistor R7 is connected to VCC, and the other end of resistor R8 is connected to the ground end of R4.

[0015] The resistance values ​​of external resistors R2, R3, R4, R5, and R8 that meet the output requirements are calculated comprehensively. Resistors R6 and R7 are fixed values ​​of 30KΩ and 120KΩ respectively. Only resistors R2, R3, R4, R5, and R8 are adjustable thick film resistors that need to match the pressure sensor chip. In order to compensate for the fact that the resistance values ​​of the internal resistors of the pressure sensor chip, namely R11, R12, R13, and R14, change too much with temperature and pressure, resulting in excessive sensitivity and temperature drift parameters, compensation design is carried out. According to the compensation circuit principle Figure 3 The following formula can be obtained:

[0016] in,

[0017] Solving this system of equations, we can obtain: U3 = (VCC / R3 + F2 * F3 - F7 * F2 / F4 / (R11 + R12 + R2)) / (F6 -F7 * F5 / F4); U2 = F5 / F4 * U3 - F2 / F4 / (R11 + R12 + R2); U5 = F1 * U3 - R14 * U2 / R13 - F2; U1 = U2 + (U5 - U2) * (R12 + R2) / (R11 + R12 + R2); U13 = U3 - U1; Uout = U13 * Gain; in, F1 = 1 + R14 / R13 + R14 / R6 - R14 * R7 * R8 / (R6 * R7 * R8 + R6 *R6 * R8 + R6 * R6 * R7); F2 = VCC * R14 * R8 / (R7 * R8 + R6 * R8 + R7 * R6); F3 = 1 / (R11 + R12 + R2) + 1 / R3 + 1 / R14; F4 = 1 / R4 + 1 / (R11 + R12 + R2) + 1 / R13 + R14 / (R11 + R12 + R2) / R13; F5 = F1 / (R11 + R12 + R2) + 1 / R13; F6 = F3 * F1 - 1 / R14; F7 = R14 * F3 / R13 + 1 / (R11 + R12 + R2); Gain = 49.4 * 1000 / R9 + 1.

[0018] The calculation is performed in an iterative manner to select the best result. That is, according to the resistance and voltage value at RO (known), the current value flowing through the resistors R11, R12, R13, and R14 is calculated, and the resistance values ​​of R11, R12, R13, and R14 are obtained by combining the values ​​of V, V1, V2, V3, and V4 read from the EXCEL table.

[0019] At this time, R2 is set to 14Ω, R5 is set to 100000Ω, R8 is set to 7000Ω, R3 is set to 1000Ω, and R4 is set to 1000Ω. Substitute them into the above formula, and gradually calculate the normal temperature output voltage Vout and determine whether it meets the requirements? If it meets the requirements, calculate the low temperature output voltage Vout and determine whether it meets the requirements? If it meets the requirements, calculate the high temperature output voltage Vout and determine whether it meets the requirements? If all meet the requirements, the iteration ends, and the resistance values ​​of R2, R3, R4, R5, and R8 at this time are output as the result. If it does not meet the requirements, it is necessary to start with the resistance value of R2 and step R2, R5, R8, R3, and R4 with an increase value of 1Ω each time, that is, R2 is set to 15Ω, R5 is set to 100000Ω, R8 is set to 7000Ω, R3 is set to 1000Ω, and R4 is set to 1000Ω. Substitute them into the above formula and calculate again until the optimal solution is obtained.

[0020] Fourth, the compensation solution formula is implemented using a programming language to calculate the result. The computer program is as follows: Figure 4 shown.

Claims

1. An automatic testing method for integrated circuit resistance characteristics, characterized in that The following steps are involved: 1) Automatically test the chips and voltage regulators used in the integrated circuit at normal temperature and pressure, normal temperature and low pressure, low temperature and normal pressure, and high temperature and normal pressure, and extract the corresponding data; 2) Resistance detection is performed by powering on and performing voltage testing; 3) Input data in Excel form, either individually or in batches; 4) According to the product technical index requirements, determine the compensation calculation target and set the intuitive target value; 5) Comprehensively calculate the external resistor value that meets the output requirements through the compensation circuit schematic; The calculation is carried out in an iterative manner to select the best result; 6) and use programming language to realize the calculation result of the compensation solution formula.

2. The automatic testing method of integrated circuit resistance characteristics according to claim 1, characterized in that: If the external resistor value calculated in step 5) does not meet the requirements, it is necessary to increase the external resistor value by 1Ω at a time and then perform comprehensive calculations until the optimal solution is obtained.

Images