MOSFET wafer proximity particle test method and test circuit thereof

Abstract

The application discloses a MOSFET wafer adjacent particle testing method and a testing circuit thereof, and the testing method comprises the following steps: S101, connecting the drain loading end and the drain measuring end of the MOSFET wafer through a resistor; S102, judging the basic function of N measured MOSFET particles to be normal by testing a small current parameter of VTH; S103, testing Rdson, and selecting a particle closest to the measured particle as an auxiliary particle; S104, driving the gate of the auxiliary particle to be always on; and S105, connecting the measuring end of the common drain to the source of the auxiliary particle, and then testing the Rdson parameter; the application further discloses a MOSFET wafer adjacent particle testing circuit, and the testing circuit can improve the measurement accuracy of the Rdson parameter of the MOSFET wafer and effectively reduces the testing error.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of discrete device testing, in particular to a MOSFET wafer adjacent particle testing method and testing circuit thereof. BACKGROUND

[0002] The drain measurement end of the MOSFET is connected to the object table, even if the internal resistance of the object table is very low and the error is negligible, the equivalent resistance on the drain substrate current path will be added to the value of the measured device Rdson (on-resistance), so that the drain loop is no longer a standard Kelvin connection, which causes a large amount of measurement error. This measurement error is unstable, when the bottom contact of the measured particle is good, the error is small, when the bottom contact of the measured particle and the particles near the bottom contact are not good, the error is large.

[0003] In order to reduce the error, the wafer and the CHUNK table should be as tightly fitted as possible, and the gap in the middle should be as small as possible. In this way, the path length from the common drain measurement end to the measured device can be reduced, and the resistance of the non-Kelvin connection part can be reduced. When the additional resistance caused by the drain is much smaller than Rdson (on-resistance), the test result is reliable. This test method puts high requirements on the flatness and surface contact resistance of the object table.

[0004] The current test scheme mostly improves the flatness of the object table by plating a thick gold layer on the object table to weaken the impact of uneven contact, but this greatly increases the cost of the probe table, so the standard adjacent particle method is generated. However, the traditional adjacent particle method has a serious problem, that is, when the auxiliary particle used to implement the adjacent particle method is a bad die, the measured particle cannot be tested, and the system will directly judge this particle as a failed die, causing the yield to decrease. SUMMARY

[0005] The purpose of the present application is to overcome the defects of the prior art, and provide a MOSFET wafer adjacent particle testing method and testing circuit thereof, which can improve the measurement accuracy of the Rdson (on-resistance) parameter of the MOSFET wafer and effectively reduce the test error.

[0006] In order to achieve the purpose of the present application, the technical scheme adopted is:

[0007] The application discloses a MOSFET wafer adjacent particle testing method and a testing circuit thereof, and the testing method comprises the following steps: S101, connecting the drain loading end and the drain measuring end of the MOSFET wafer through a resistor; S102, judging the basic function of N measured MOSFET particles to be normal by testing a small current parameter of VTH; S103, testing Rdson (on-resistance), and selecting a particle closest to the measured particle as an auxiliary particle; S104, driving the gate of the auxiliary particle to be always on; and S105, connecting the measuring end of the common drain to the source of the auxiliary particle, and then testing the Rdson (on-resistance) parameter, and the application further discloses a MOSFET wafer adjacent particle testing circuit, which can improve the measurement accuracy of the Rdson (on-resistance) parameter of the MOSFET wafer and effectively reduces the testing error.

[0008] The application further is that the number of the N measured particles is consistent with the number of the circuit arms of the testing station, and the greater the N value is, the lower the misjudgment rate is.

[0009] The application further is that the gate driving voltage is kept within ±5V, so that the always on state can be kept.

[0010] The application further is that the particle closest to the measured particle is an abnormal particle in the small current parameter test, and therefore the particle next closest to the measured particle is selected as the auxiliary particle.

[0011] The application further is that the adjacent particle testing method measures the yield of the measured MOSFET wafer to be 90%, the misjudgment rate is 0.1% when four stations are used, and the misjudgment rate is 0.00001% when eight stations are used.

[0012] The application has the following advantages of the transient thermal resistance testing circuit:

[0013] The MOSFET wafer adjacent particle testing method and the testing circuit thereof can improve the measurement accuracy of the Rdson (on-resistance) parameter of the MOSFET wafer and effectively reduce the testing error. BRIEF DESCRIPTION OF DRAWINGS

[0014] The application will be further described in detail in combination with the drawings and specific embodiments.

[0015] Figure 1 It is a MOSFET wafer adjacent particle testing method flow chart;

[0016] Figure 2 It is a four-station MOSFET wafer testing circuit diagram;

[0017] Figure 3 It is a four-station improved adjacent particle method MOSFET wafer testing principle diagram; Detailed Implementation

[0018] The following is a more detailed description of a MOSFET wafer proximity particle testing method and its testing circuit, with reference to schematic diagrams, illustrating preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0019] For clarity, not all features of the actual embodiments are described. In the following description, well-known functions and structures are not detailed in detail, as they would obscure the invention with unnecessary detail. It should be understood that in the development of any actual embodiment, numerous implementation details must be made to achieve the developer's specific objectives, such as changes from one embodiment to another according to limitations related to the system or business. Furthermore, it should be understood that such development work may be complex and time-consuming, but is merely routine work for those skilled in the art.

[0020] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0021] Example 1:

[0022] like Figure 1 As shown in the figure, this embodiment provides a method and circuit for testing adjacent MOSFET wafer particles. The testing method includes the following steps: S101, connecting the drain loading terminal and drain measurement terminal of the MOSFET wafer through a resistor; S102, determining the basic functionality of N tested MOSFET particles by testing the VTH small current parameter; S103, testing Rdson (on-resistance), selecting the particle that is functional and closest to the tested particle as an auxiliary particle; S104, driving the gate of the auxiliary particle to a normally on state; S105, connecting the common drain measurement terminal to the source of the auxiliary particle, and then performing Rdson (on-resistance) parameter testing.

[0023] The number of N particles to be tested is consistent with the number of circuit arms at the test station, and the larger the value of N, the lower the test misjudgment rate.

[0024] The gate drive voltage is kept within ±5V to maintain the normally open state.

[0025] The nearest particle to the tested particle was found to be abnormal during low-current parameter testing; therefore, the next closest particle was selected as the auxiliary particle.

[0026] The proximity particle testing method measures the yield of the MOSFET wafer under test to be 90%, with a false positive rate of 0.1% at four stations and a false positive rate of 0.00001% at eight stations.

[0027] Example 2:

[0028] like Figure 2 As shown in the embodiment, a MOSFET wafer proximity particle testing method and its testing circuit are used to test the Rdson (on-resistance) test parameters of a MOSFET wafer, including a testing module, a MOSFET, a switch, and a stage;

[0029] The gate of the MOSFET is connected to the sampling port and output port of test module A, and the source of the MOSFET is connected to the sampling port and output port of test sampling module C.

[0030] The B port of the test module at the workstation is connected to the common drain of the MOSFET under test via a switch.

[0031] The MOSFET wafer under test is placed on the stage;

[0032] The method for testing the Rdson (on-resistance) parameter of MOSFET wafer proximity particles, using 4SITE parallel testing as an example, is described below:

[0033] S201: When the particle being measured is Die1, close switch K3 and use Die2 as the neighboring particle;

[0034] S202: Apply current I to the loading terminal of port B of Die1, and apply a drive voltage to the loading terminal of port A to turn on the gate of the MOSFET.

[0035] S203: Apply a drive voltage to the loading terminal of port A of Die2 to turn on the source and drain of Die2;

[0036] S204: Measure the voltage V between the measuring terminal of port C of Die1 and port C of Die2;

[0037] S205: According to the formula Calculate the value of Rdson (on-resistance);

[0038] In conclusion, the above method is feasible for testing the Rdson (on-resistance) parameter of MOSFET wafers, and it effectively improves the testing accuracy and reduces the testing error.

[0039] It should be understood that the specific embodiments described above are only for explaining the present invention and are not intended to limit the present invention. Obvious variations or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A MOSFET wafer adjacent particle test method for testing the on-resistance Rdson test parameter of a MOSFET wafer, the test method comprising the following steps: S101: connecting the drain load end and the drain measurement end of the MOSFET wafer through a resistor; S102: determining the normal function of N measured MOSFET particles by testing the VTH small current parameter; S103: selecting the particle closest to the measured particle as the auxiliary particle if the particle closest to the measured particle is an abnormal particle in the small current parameter test, and selecting the second closest particle as the auxiliary particle; S104: driving the gate of the auxiliary particle to a constant-on state; S105: connecting the measurement end of the common drain to the source of the auxiliary particle, and then testing the on-resistance Rdson parameter. The number of N measured MOSFET particles is consistent with the number of circuit arms of the test station, and multi-station parallel testing is performed.

2. The MOSFET wafer proximity particle test method of claim 1, wherein, The gate drive voltage is kept within ±5V to drive the gate of the auxiliary particle to a constant-on state.

3. The MOSFET wafer proximity particle test method of claim 1, wherein, The MOSFET wafer adjacent particle test method has a measured MOSFET wafer yield of 90%, a misjudgment rate of 0.1% for four stations, and a misjudgment rate of 0.00001% for eight stations.

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