Micro resistance measuring device and method

Abstract

The invention provides a micro resistance measuring device and method. The device comprises an installation module and a micro resistance testing module. The micro resistance test module comprises a first switch, a second switch, a third switch, a fourth switch and a connecting end connected to the current source; the first switch and the second switch are connected in series and then connected with the current source; the third switch and the fourth switch are connected in series and then connected with the current source; the connecting end of the first switch and the second switch is connected with one end of the mounting module, and the other end of the mounting module is connected to the connecting end of the third switch and the fourth switch; one ends of the first switch and the third switch away from the mounting module are respectively connected with a voltage measuring unit; the installation module is used for installing a chip to be tested or a calibration module, and the calibration module comprises a chip unit and a calibration resistor; existing testing equipment can be adopted, the measuring efficiency and the measuring precision of the micro resistance of the chip are improved through simple improvement of the testing device, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of electrical parameter measurement technology, and in particular to a device and method for measuring minute resistance. Background Technology

[0002] In existing chip packaging and testing processes, the chip needs to be precisely placed in a dedicated test socket for measuring electrical parameters (such as the sampling resistance of a current acquisition chip). During this process, the chip pins make physical contact with the test socket probes, introducing contact resistance. This contact resistance can be significantly larger than the minute resistance within the chip itself. Therefore, the influence of this contact resistance on the measurement results must be eliminated; otherwise, measuring the minute resistance within the chip would be meaningless.

[0003] To counteract the negative impact of contact resistance, the industry typically employs two types of solutions: one is to use precision measuring devices designed for measuring minute resistances at chip pins, thereby reducing the introduction of contact resistance and line resistance at the hardware level; the other is to improve the measurement circuit structure to eliminate the interference of contact resistance on the measurement results at the principle level.

[0004] However, both of these approaches have significant limitations: the former requires highly expensive precision measurement equipment, which is not conducive to cost control in large-scale mass production scenarios; while optimizing the circuit structure, the latter inevitably increases measurement errors, and the subsequent process of investigating, analyzing and resolving these errors will further reduce the overall efficiency of micro-resistance measurement and affect the production capacity of the testing process. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a micro-resistance measuring device and method, which solves the problem of the inability to balance cost and testing efficiency in micro-resistance measurement in existing technologies.

[0006] According to an embodiment of the present invention, a first aspect provides a micro-resistance measuring device, comprising: a mounting module, a current source, and a micro-resistance testing module;

[0007] The micro-resistance testing module includes a first switch, a second switch, a third switch, a fourth switch, and a connection terminal connected to a current source;

[0008] The first switch and the second switch are connected in series and then connected to the current source to form the first test circuit;

[0009] The third and fourth switches are connected in series and then connected to the current source to form the second test circuit;

[0010] The connection terminals of the first and second switches are connected to one end of the mounting module, and the other end of the mounting module is connected to the connection terminals of the third and fourth switches to form a test path for the micro-resistance.

[0011] The ends of the first and third switches furthest from the mounting module are respectively connected to voltage measuring units to obtain the corresponding measuring voltages.

[0012] The mounting module is used to mount the chip under test or calibration module, and to lead out the pins of the chip under test or calibration module that require the measurement of minute resistance to the minute resistance test module; the calibration module includes a chip unit and a calibration resistor; wherein, the calibration resistor is disposed on one side of the chip unit or in the chip unit, and the two ends of the calibration resistor are respectively connected to two measurement pins of the chip unit to form a current path.

[0013] Optionally, the chip unit has the same package pins as the chip under test; the two ends of the calibration resistor are led out to the voltage measurement pins or voltage measurement terminals of the chip unit to connect the voltage measurement unit to form a voltage measurement path; the intersection of the current path and the voltage measurement path is the two ends of the calibration resistor.

[0014] Optionally, in the calibration module, the length of the electrical wire between the chip cell and the calibration resistor is less than the length of the chip cell pins.

[0015] Optionally, the number of the installation modules is multiple, and correspondingly, the number of the micro-resistance testing modules is multiple.

[0016] Optionally, it may also include a control unit and an interaction unit and a storage unit electrically connected to the control unit, wherein the control unit or storage unit is used to store measurement information of the calibration module; and the interaction unit is used for human-computer interaction.

[0017] Optionally, the control unit is also used to analyze the error resistance measurement, which is the contact resistance of the chip under test on the mounting module and the line resistance between the mounting module and the pin portion of the chip under test; the control unit outputs the calibration resistance value or measurement error through the interaction unit.

[0018] On the other hand, according to embodiments of the present invention, a method for measuring minute resistance is also provided, using the minute resistance measuring device described above, the method comprising the following steps:

[0019] Install the chip under test or calibration module on the mounting module;

[0020] Close the first and second switches, open the third and fourth switches, and obtain the voltage drop V1 formed by the set current I in the first test circuit;

[0021] Close the third and fourth switches, open the first and second switches, and obtain the voltage drop V2 formed by the set current I in the second test circuit;

[0022] Close the first and fourth switches, open the second and third switches to form the third test circuit, and obtain the voltage drop V3 formed by the set current I in the third test circuit;

[0023] Close the second and third switches, open the first and fourth switches to form the fourth test circuit, and obtain the voltage drop V4 formed by the set current I in the fourth test circuit;

[0024] Calculate the resistance Rx to be measured. The formula is Rx = ((V3+V4)-(V1+V2)) / 2 / I.

[0025] Optionally, the method also includes a chip contact resistance calibration method, which subtracts the resistance r from the resistance to be measured Rx to obtain the calibrated resistance to be measured Rx0, where the resistance r is the sum of the contact resistance between the calibration module and the mounting module and the line resistance between the mounting module and the chip pin portion, and the resistance r is obtained through the following steps:

[0026] Install the calibration module on the mounting module;

[0027] The resistance value Rt of the calibration resistor in the calibration module is measured using the above method;

[0028] Measure the voltage Vt across the calibration resistor; the intersection of the measurement path of voltage Vt and the path of the current source set through the calibration resistor is at both ends of the calibration resistor.

[0029] The resistance r is calculated using the formula r = Rt - Vt / I.

[0030] Optionally, by measuring the calibration module multiple times, the measurement parameters and measurement time of the calibration module are stored to form a historical measurement calibration parameter set and statistical analysis. One of the minimum, average, mode, median and maximum values ​​in the historical valid data analysis is denoted as r0 and used as the resistor r to correct the resistor under test. The historical valid data is data within a specified time period or data with noise removed. The noise is statistical outliers or values ​​obtained under erroneous measurement conditions.

[0031] Optionally, there are multiple calibration modules, and IDs are set for each calibration module to obtain measurement records and statistical analysis of different contact subjects based on different calibration modules.

[0032] Compared with the prior art, the present invention has the following beneficial effects: After the chip under test is installed in the mounting module, the switching resistance of the first switch, the second switch, the third switch and the fourth switch in the closed state can be obtained through the first test circuit and the second test circuit, and the contact resistance corresponding to the chip unit with the same pin package can be obtained through the calibration module. Since the voltage obtained is the voltage across the calibration resistor, the influence of the line resistance of the chip pin and the contact resistance can be obtained and corrected through the calibration module, thereby solving the problem of high cost and accurate measurement of chip micro resistance while ensuring measurement efficiency. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the composition structure of the micro resistance measuring device according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the circuit principle of the micro-resistance measurement module according to an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of one embodiment of the calibration module of the present invention;

[0036] Figure 4 This is a schematic diagram illustrating another embodiment of the calibration module of the present invention;

[0037] Figure 5 This is a schematic block diagram of calibration hardware according to one embodiment of the calibration module of the present invention. Detailed Implementation

[0038] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] like Figure 1 , Figure 2 As shown, this embodiment of the invention proposes a micro resistance measuring device, including a mounting module 10, a micro resistance testing module 20, and a current source;

[0040] The micro resistance testing module includes a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, and a connection terminal connected to a current source.

[0041] Among them, the first switch S1 and the second switch S2 are connected in series and then connected to the current source to form the first test circuit;

[0042] The third switch S3 and the fourth switch S4 are connected in series and then connected to the current source to form the second test circuit;

[0043] The connection terminals of the first switch S1 and the second switch S2 are connected to one end of the mounting module, and the other end of the mounting module is connected to the connection terminals of the third switch S3 and the fourth switch S4 to form a test path for the micro-resistance.

[0044] The ends of the first switch S1 and the third switch S3 furthest from the mounting module are respectively connected to voltage measuring units to obtain the corresponding measuring voltages V1 and V2.

[0045] The mounting module is used to mount the chip under test (DUT) or calibration module, and to lead the pins of the DUT or calibration module that require the measurement of minute resistances to the minute resistance test module, such as... Figure 3 , Figure 4 The calibration module includes a chip unit 1 and a calibration resistor 2. Figure 4 (The electrical conductors are not shown in the diagram). The calibration resistor 2 is disposed on one side of the chip unit 1 or within the chip unit 1. The two ends of the calibration resistor 2 are respectively connected to two measurement pins of the chip unit to form a current path. The chip unit 1 has the same package pins as the chip under test. The two ends of the calibration resistor 2 are led out to the voltage measurement pins or terminals of the chip unit to connect to the voltage measurement unit and form a voltage measurement path. The intersection of the current path and the voltage measurement path is the two ends of the calibration resistor. Since the measured voltage path only contains the calibration resistor itself and does not include the voltage drop caused by contact resistance or line resistance, indirect measurement values ​​of contact resistance and line resistance can be obtained through the calibration module. Considering the influence of the bonding wire resistance, in the calibration module, the length of the electrical conductor between the chip unit and the calibration resistor is less than the length of the chip unit pins to avoid calibration deviations caused by the large difference in length due to the line resistance of the calibration module.

[0046] The number of installation modules is multiple, and correspondingly, the number of micro-resistance testing modules is multiple, in order to achieve rapid batch testing.

[0047] like Figure 5 As shown, it also includes a control unit and an interaction unit and a storage unit electrically connected to the control unit. The control unit or storage unit is used to store the measurement information of the calibration module; the interaction unit is used for human-machine interaction; the control unit is also used to analyze the error resistance measurement, which is the contact resistance of the chip under test on the mounting module and the line resistance between the mounting module and the pin portion of the chip under test; the control unit outputs the calibration resistance value or measurement error through the interaction unit; correspondingly, the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 are electrically controlled switches. The operator can trigger the action of the electrically controlled switches through the interaction unit by the control unit, or perform automatic testing according to the sequence of preset test steps.

[0048] This embodiment also proposes a method for measuring minute resistance, using the minute resistance measuring device described above, and the method includes the following steps:

[0049] Install the chip under test or calibration module on the mounting module;

[0050] Close the first switch S1 and the second switch S2, open the third switch S3 and the fourth switch S4, and obtain the voltage drop V1 formed by the set current I in the first test circuit, referring to... Figure 2 This voltage drop is the voltage drop across the switching resistors R1 and R2 when the first switch S1 and the second switch S2 are closed or open, i.e., I*(R1+R2).

[0051] Close the third switch S3 and the fourth switch S4, open the first switch S1 and the second switch S2, and obtain the voltage drop V2 formed by the set current I in the second test circuit. This voltage drop is the voltage drop formed on the switching resistors R3 and R4 when the third switch S3 and the fourth switch S4 are closed or open, i.e., I*(R3+R4).

[0052] Close the first switch S1 and the fourth switch S4, and open the second switch S2 and the third switch S3 to form the third test circuit. Obtain the voltage drop V3 formed by the set current I in the third test circuit, i.e., I*(R1+R4+R5+R6); where R5 and R6 are the contact resistance between the chip under test and the mounting module, as well as part of the line resistance.

[0053] Close the second and third switches, open the first and fourth switches to form the fourth test circuit, and obtain the voltage drop V4 formed by the set current I in the fourth test circuit, i.e., I*(R2+R3+R5+R6).

[0054] The resistance to be measured, Rx, is calculated using the formula Rx = ((V3 + V4) - (V1 + V2)) / 2 / I, which includes the influence of R5 and R6. When the resistance to be measured is more than 5 times the contact resistance or the measurement accuracy is not high, Rx can meet the resistance measurement value under general conditions.

[0055] As one embodiment, a chip contact resistance calibration method is also included, in which the resistance to be measured Rx is subtracted from the resistance r to obtain the calibrated resistance to be measured Rx0, wherein the resistance r is the sum of the contact resistance between the calibration module and the mounting module and the line resistance between the mounting module and the chip pin portion, i.e., r = R5 + R6; the resistance r is obtained through the following steps:

[0056] Install the calibration module on the mounting module;

[0057] The resistance value Rt of the calibration resistor in the calibration module is measured by measuring Rx.

[0058] Measure the voltage Vt across the calibration resistor; the intersection of the measurement path of voltage Vt and the path of the current source set through the calibration resistor is at both ends of the calibration resistor.

[0059] Calculate the resistance r using the formula r = Rt - Vt / I. (Reference) Figure 3Since there is no current in the conductor 4 of the voltage measurement path (the internal resistance of the voltage measurement unit is infinite), the voltage drop caused by the line resistance of the current source at the pin of chip unit 1 and the conductor 3 of the current path, as well as the contact resistance, does not affect the accurately measured voltage value, thus enabling accurate correction of the measurement resistance.

[0060] By repeatedly measuring and calibrating the module, the measurement parameters and measurement times of the calibration module are stored to form a historical measurement calibration parameter set and statistical analysis. One of the minimum, average, mode, median, and maximum values ​​from the historical valid data analysis is denoted as r0 and used as the resistance r to correct the resistance under test. The historical valid data is data from a specified time period or data with noise removed; the noise refers to statistical outliers or values ​​obtained under erroneous measurement conditions. In another embodiment, multiple calibration modules are used, and IDs are set for each module to obtain measurement records and statistical analysis of different contact subjects based on different calibration modules. Through the historical data of the calibration modules or multiple calibration modules, changes in contact resistance can be tracked, or the influencing factors of contact resistance can be compared to determine the reliability of the installation module or calibration module.

[0061] Example 2

[0062] The difference between this embodiment and Embodiment 1 lies in adjusting the error analysis logic or method of the control unit based on the ratio of contact resistance to the resistance to be measured.

[0063] Multiple calibration modules contain N standard resistors, with N standard resistors of different resistance values ​​installed;

[0064] The nth measured resistance value is obtained by measuring the nth standard resistor, and the nth calibration error between the nth measured resistance value and the nth target resistance value is calculated.

[0065] A full-range error table is generated based on N target resistance values ​​of N standard resistors and N calibration errors. The full-range error table is used to output calibration errors based on the calibration module.

[0066] In the above steps, a better approach is to use N standard resistors with different resistance values ​​to cover the range of the micro-resistance measuring device, such as 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% of the range.

[0067] Based on the aforementioned full-range error table, this embodiment of the invention fine-tunes the parameters of the measurement loop in hardware to achieve error zeroing. Therefore, based on the calibration error, the initial measurement result is zeroed out, and the target resistance value of the chip under test is output, including:

[0068] Adjust the parameters of the current source according to the calibration error provided by the full-range error table;

[0069] The micro-resistance measuring device outputs the target resistance value of the chip under test based on the adjusted parameters of the current source.

[0070] In another embodiment, the calibration error is obtained by minimizing the result error using a correction coefficient derived from a software algorithm, thereby maximizing the stability and accuracy of the measurement results, including:

[0071] The micro-resistance measuring device is equipped with N standard resistors of different resistance values;

[0072] The nth measured resistance value is obtained by measuring the nth standard resistor, and the nth calibration error between the nth measured resistance value and the nth target resistance value is calculated.

[0073] A correction factor is calculated based on N target resistance values ​​of N standard resistors and N calibration errors. The correction factor is used to output the calibration error based on the calibration module.

[0074] In the above steps, the algorithm for calculating the correction coefficient based on the N target resistance values ​​of N standard resistors and the N calibration errors can be an algorithm based on a linear model (such as the least squares method) or an algorithm based on a nonlinear model (such as the lookup table interpolation method). This embodiment of the invention does not limit it.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A micro-resistance measuring device, characterized in that, include: Installation module, current source and micro resistance test module; The micro-resistance testing module includes a first switch, a second switch, a third switch, a fourth switch, and a connection terminal connected to a current source; The first switch and the second switch are connected in series and then connected to the current source to form the first test circuit; The third and fourth switches are connected in series and then connected to the current source to form the second test circuit; The connection terminals of the first and second switches are connected to one end of the mounting module, and the other end of the mounting module is connected to the connection terminals of the third and fourth switches to form a test path for the micro-resistance. The ends of the first and third switches furthest from the mounting module are respectively connected to voltage measuring units to obtain the corresponding measuring voltages. The mounting module is used to mount the chip under test or calibration module, and to lead out the pins of the chip under test or calibration module that require the measurement of minute resistance to the minute resistance test module; the calibration module includes a chip unit and a calibration resistor; wherein, the calibration resistor is disposed on one side of the chip unit or in the chip unit, and the two ends of the calibration resistor are respectively connected to two measurement pins of the chip unit to form a current path.

2. The micro-resistance measuring device as described in claim 1, characterized in that, The chip unit has the same package pins as the chip under test; the two ends of the calibration resistor are led out to the voltage measurement pins or voltage measurement terminals of the chip unit to connect the voltage measurement unit to form a voltage measurement path; the intersection of the current path and the voltage measurement path is the two ends of the calibration resistor.

3. The micro-resistance measuring device as described in claim 2, characterized in that, In the calibration module, the length of the electrical wire between the chip cell and the calibration resistor is less than the length of the chip cell pins.

4. The micro-resistance measuring device as described in claim 1, characterized in that, The number of installation modules is multiple, and correspondingly, the number of micro-resistance testing modules is multiple.

5. The micro-resistance measuring device as described in claim 2, characterized in that, It also includes a control unit and an interaction unit and a storage unit electrically connected to the control unit. The control unit or storage unit is used to store the measurement information of the calibration module; the interaction unit is used for human-computer interaction.

6. The micro-resistance measuring device as described in claim 5, characterized in that, The control unit is also used to analyze the error resistance measurement, which is the contact resistance of the chip under test on the mounting module and the line resistance between the mounting module and the pin portion of the chip under test; the control unit outputs the calibration resistance value or measurement error through the interaction unit.

7. A method for measuring minute resistance, characterized in that, The method of using the micro-resistance measuring device as described in any one of claims 1 to 6 includes the following steps: Install the chip under test or calibration module on the mounting module; Close the first and second switches, open the third and fourth switches, and obtain the voltage drop V1 formed by the set current I in the first test circuit; Close the third and fourth switches, open the first and second switches, and obtain the voltage drop V2 formed by the set current I in the second test circuit; Close the first and fourth switches, open the second and third switches to form the third test circuit, and obtain the voltage drop V3 formed by the set current I in the third test circuit; Close the second and third switches, open the first and fourth switches to form the fourth test circuit, and obtain the voltage drop V4 formed by the set current I in the fourth test circuit; Calculate the resistance Rx to be measured. The formula is Rx = ((V3+V4)-(V1+V2)) / 2 / I.

8. A method for measuring minute resistance as described in claim 7, characterized in that, It also includes a chip contact resistance calibration method, which subtracts the resistance r from the resistance to be measured Rx to obtain the calibrated resistance Rx0, where the resistance r is the sum of the contact resistance between the calibration module and the mounting module and the line resistance between the mounting module and the chip pin portion. The resistance r is obtained through the following steps: Install the calibration module on the mounting module; The resistance value Rt of the calibration resistor in the calibration module is measured using the method of claim 6; Measure the voltage Vt across the calibration resistor; the intersection of the measurement path of voltage Vt and the path of the current source set through the calibration resistor is at both ends of the calibration resistor. The resistance r is calculated using the formula r = Rt - Vt / I.

9. A method for measuring minute resistance as described in claim 8, characterized in that, By repeatedly measuring and calibrating the module, the measurement parameters and measurement time of the calibration module are stored to form a historical measurement calibration parameter set and statistical analysis. One of the minimum, average, mode, median and maximum values ​​in the historical valid data analysis is denoted as r0 and used as the resistor r to correct the resistor under test. The historical valid data is data within a specified time period or data with noise removed. The noise is statistical outliers or values ​​obtained under erroneous measurement conditions.

10. A method for measuring minute resistance as described in claim 7, characterized in that, The calibration module consists of multiple modules, and each module is assigned an ID to obtain measurement records and statistical analysis of different contact subjects based on the different calibration modules.

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