TWI426289B - Radio frequency scattering parameter correction method with three correctors - Google Patents

Description

Radio frequency scattering parameter correction method with three correctors

The invention relates to a radio frequency scattering parameter measurement and correction method and a measurement structure thereof, in particular to a radio frequency scattering parameter measurement de-embedding correction method for a one-tier semiconductor wafer component or other substrate component And its measurement structure.

When the general signal is in the RF microwave frequency band, it is difficult to measure its voltage and current directly. Therefore, in this frequency band, it should be discussed in the form of fluctuations, which are used for incidence, reflection and absorption to measure the scattering parameters. Since the entire measurement system needs to go through a series of complicated processes, it is necessary to use the measurement correction to improve the measurement accuracy. The measurement error can be characterized by the mathematical method of the error matrix, and the measurement error is divided into random, drift, And systemic three major errors, wherein the systematic error can be measured by the network analyzer in a stable measurement environment, and the error amount can be further determined, which is the measurement correction.

In practice, the calibration procedure is implemented to adjust the initial state of the instrument from the initial state after booting to the actual measurement environment defined by the user to remove errors other than the object to be tested. The Scattering parameter measurement is traditionally a two-stage process with the following steps:

1. Correct the system before the measurement to remove the effects caused by the measuring instrument and the environment. Therefore, the probe is first calibrated with the Impedance Standard Substrate (ISS). The calibration method can be SOLT (Short-Open-Load-Thru) or LRM (Line-Reflect-Match); then move the measurement reference plane to the probe tip, but the probe pad and the in-wafer test component still have Small segment of the connection line, and the large-area probe contact capacitance effect cannot be calibrated;

2. Then measure the additional dummy structure (Dummy structure, such as Short, Open, Thru, etc.) on the wafer to remove the contact and connection line effects, which is the de-embedding program, so go The main purpose of the inlay is to remove the test fixture effect from the measurement data from the original test results to obtain the most primitive characteristics of the component.

However, this two-stage measurement method has the following disadvantages:

1. The high-frequency characteristics of the additional virtual structure on the wafer are not easy to know. If it is assumed to be an ideal characteristic, the de-embedding result will introduce a large error at high frequencies;

2. Two-stage measurement consumes wafer probe test time, so it becomes very important when applied to a large number of tests;

3. Since the Impedance Standard Substrate (ISS) is expensive, the contact is degraded by the probe scratching characteristics after each test, so it needs to be replaced after a certain number of times, thus increasing the test cost. .

In view of the above shortcomings, some documents have mentioned solutions, and their contents are as follows:

1. IEEE Trans. Electron Devices , vol. 54, no. 10, pp. 2706-2714, Oct. 2007 , which refers to the use of one-stage measurement for de-embedding, but the disadvantage is that five The virtual structure (Open, Short, Thru, Left, Right), so its accuracy will be sacrificed compared to the two-stage approach.

2. IEEE Trans. Microwave Theory Tech. , vol. 51, pp. 2391-2401, Dec. 2003 , which refers to the development of Multiline Thru-Reflect-Line (TRL) by NIST (National Institute of Standards and Technology). The calibration method can complete the calibration and de-embedding procedures in one stage, but the disadvantage is that a multi-segment transmission line is required, which is very expensive.

Therefore, if a radio frequency scattering parameter measurement calibration method and a measurement structure thereof can be provided, the RF scattering parameter measurement de-embedding procedure of the one-stage semiconductor wafer component or other substrate component can be performed without using a standard impedance plate. And only need three correction parts to solve the operation, it should be an optimal solution.

The object of the present invention is to provide a radio frequency scattering parameter measurement and correction method in order to improve the accuracy of the scattering parameter measurement and to perform a de-embedding process using a one-stage measurement.

Another object of the present invention is to provide a radio frequency scattering parameter measurement and correction method capable of applying an L-OS-OT (Line, Offset-Series, Offset-Shunt, line segment-attenuation series resistance-capture parallel resistance). The correction method is used to achieve the measurement of the broadband, and the known conditions provided by the corrector can be used to solve the same or a larger number of unknowns for self-correction purposes.

The radio frequency scattering parameter measurement and correction method and the measurement structure thereof can achieve the self-correction, and the RF scattering parameter measurement structure comprises a transmission line segment corrector, an offset series element corrector, An offset parallel component corrector and a test object measuring device, wherein the transmission line of the offset series component corrector and the complementary parallel component corrector is the same as the transmission line length of the object to be tested, so that the offset series component is corrected The offset component corrector and the object to be tested have the same error box, and after obtaining the scattering parameter matrix of the error box by the calibration method, the electronic component to be tested can be connected to the object to be tested And the uncorrected measurement data is calculated to obtain the radio frequency scattering parameter of the object to be tested.

More specifically, the radio frequency scattering parameter measurement correction method is for subtracting the error added during the measurement, and the characteristics of the error quantities are represented by a mathematical model, and the transmission line segment corrector and the offset series element correction are performed. After the measurement is performed by the parallel element corrector, the mathematical model can be input to calculate all the error parameters. Therefore, after repeated calculation, the error value of the required calibration can be obtained, and further can be obtained. The parameter value of the actual object to be tested is obtained.

More specifically, the transmission line segment corrector includes two transmission lines and one transmission line segment, wherein the transmission line segment is connected between the two transmission lines.

More specifically, the offset series component corrector includes two transmission lines, an offset transmission line, and a series resistor, wherein the offset transmission line and the series resistance are connected between the two transmission lines.

More specifically, the offset parallel component corrector includes two transmission lines, an offset transmission line, and a parallel resistance, wherein the offset transmission line and the parallel resistance are connected between the two transmission lines.

More specifically, the transmission line of the offset series element corrector and the offset parallel element corrector is the same as the transmission line length of the object to be tested, so that the offset series element corrector, the offset parallel element corrector, and the The measuring instrument has the same error box.

More specifically, the offset transmission line of the offset series element corrector is different from the offset transmission line length of the offset parallel element corrector.

More specifically, the transmission line segment corrector, the offset series element corrector, the offset parallel element corrector, and the object to be tested can be used for a germanium substrate, a compound semiconductor (GaAs, GaN, InP, etc.) substrate or ceramic. On the /FR-4 (epoxy fiberglass board) substrate, a microstrip or a Coplanar waveguide can be used as the connection transmission line.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Please refer to FIG. 1A, FIG. 1B and FIG. 2 for the microstrip line layout structure diagram, the coplanar waveguide layout structure diagram and the corrector equivalent circuit diagram of the radio frequency scattering parameter measurement and correction method according to the present invention. The measurement structure used in the RF scattering parameter measurement calibration method is a microwave probe as a contact interface for transmitting a microwave signal, and the microwave probe includes at least a ground terminal 11 and a signal terminal 12, and the RF scattering parameter The measurement structure used in the measurement calibration method includes: a transmission line segment corrector 2, wherein the transmission line segment corrector 2 is contacted by the microwave probe (the ground end 11 and the signal end 12), and the transmission line segment is corrected The device 2 includes two transmission lines 21 and a transmission line segment 22, wherein the transmission line segment 22 is connected between the two transmission lines 21, and the transmission line 21 is connected to the signal end 12 of the microwave probe for measurement. The component of the transmission line segment 22; an abutting series component corrector 3 is contacted by the microwave probe (the ground terminal 11 and the signal terminal 12) to the abutting series component corrector 3, and the abutting series component Corrector 3 The transmission line 31 and the series resistor 33 are connected between the two transmission lines 31, and the transmission line 31 is connected to the signal end of the microwave probe. 12 is connected to measure the characteristics of the offset transmission line 32 and the series resistor 33; and the parallel component corrector 4 is contacted by the microwave probe (the ground terminal 11 and the signal terminal 12) to contact the abutment parallel component The calibrator 4 includes the two transmission lines 41, an offset transmission line 42 and a parallel resistor 43. The offset transmission line 42 and the parallel resistor 43 are connected between the two transmission lines 41. The transmission line 41 is connected to the signal terminal 12 of the microwave probe for measuring the characteristics of the offset transmission line 42 and the parallel resistor 43. A sample measuring device 5 is grounded by the microwave probe (grounded) The terminal 11 and the signal terminal 12 are in contact with the object to be tested 5, and the device to be tested 5 includes two transmission lines 51 and a device to be tested 52, wherein the device to be tested 52 is connected to the device Between two transmission lines 51, and the transmission line 51 is connected to the microwave A needle connected to the signal terminal 12, for measuring the element characteristics of the DUT 52 (Figure 1 A and B a shown, the test element is a FET-based elements).

It is worth mentioning that, as shown in FIG. 2, the equivalent circuit expression of the series element corrector 3 ( y _sp is a high frequency parasitic element) includes:

And the equivalent circuit expression of the parallel component corrector 4 ( z _tp is a high frequency parasitic element) includes:

It is worth mentioning that the transmission line 21 of the transmission line segment corrector 2, the transmission line 31 of the offset series element corrector 3, the transmission line 41 of the complementary parallel element corrector 4, and the transmission line 51 of the object to be tested 5 The lengths are the same so that the transmission line segment corrector 2, the offset series element corrector 3, and the offset parallel element corrector 4 have the same error box as the object to be tested 5.

It is worth mentioning that the offset transmission line 32 of the offset series element corrector 3 and the offset transmission line 42 of the offset parallel element corrector 4 are different in length.

It is worth mentioning that the transmission line segment corrector 2, the offset series element corrector 3, the offset parallel element corrector 4 and the object to be tested 5 can be used for a germanium substrate, a compound semiconductor (GaAs, GaN). , InP, etc.) substrate or ceramic / FR-4 (epoxy fiberglass board) substrate.

It is worth mentioning that the transmission line segment corrector 2, the offset series element corrector 3, the offset parallel element corrector 4 and the object to be tested 5 can use a microstrip line or a coplanar waveguide ( Coplanar waveguide) as a connection transmission line, as shown in FIG. 1A, wherein the corrector (transmission line segment corrector 2, offset series element corrector 3, offset parallel element corrector 4) and the object to be tested 5 are The microstrip line is used as the connection transmission line, and as shown in FIG. 1B, wherein the correctors 2, 3, 4 and the object to be tested 5 use a coplanar waveguide as the connection transmission line.

It is worth mentioning that the microwave probe is a high frequency probe, and the probe type can be G-S-G-S-G, G-S-S-G, G-S-G (Ground-Signal-Ground) or G-S (Ground-Signal).

Please refer to FIG. 3 is a flow chart of correcting operation of a radio frequency scattering parameter measurement and correction method according to the present invention. It can be seen from the figure that the radio frequency scattering parameter measurement and correction method can solve the same or more numbers by using the known conditions provided by the corrector. The target unknown number, and the calibration process of the RF scattering parameter measurement correction method is:

1. First set the measurement reference impedance of the transmission line to Z _C and set the self-correction equation 301 with several variables, and the variable is t ( ), z , y , z _tp , y _sp ( γ is the propagation constant of the transmission line, For the length of the transmission line segment of the transmission line segment corrector, z is the normalized impedance of the series element corrector, y is the normalized admittance of the parallel element corrector, z _tp , y _sp is the high frequency parasitic element), so the self-correction equation is as follows Show:

2. With the measurement results of the transmission line segment corrector, the offset series element corrector and the offset parallel element corrector, substitute the self-correction equation and use the Newton-Raphson method to find t ( ), z , y , z _tp , y _sp value 302;

3. Obtain the error box and start the de-embedding program 303 (de-embedding can obtain the scattering parameter of the object to be tested, and the characteristic impedance of the transmission line is used as the reference impedance);

4. Finally, the Z _{C is} calculated by γ , and the transmission line reference impedance conversion is performed by Z _C to Z ₀ (generally 50 Ω), and the scattering parameter 304 of the real object to be tested with Z ₀ as the reference impedance reference is obtained.

It is worth mentioning that the self-correction equation mentioned in the process 1, where [ M ] is the transmission matrix of the measurement, and the footmarks L , OS , OT represent Line, Offset-Series, Offset, respectively. -Shunt three calibration parts, and the other foot f is the cis vector measurement result of the left side of the standard part and the right side of the standard part, and the foot r represents the left side of the standard part 2 and the right side of the side 1 Inverse vector measurement results.

It is worth mentioning that, please refer to Figure 4, which is the overall measurement of the dual-turn network architecture, in which the characteristic impedance of the transmission line in the network is Z _C , and the characteristic impedance of the transmission line of the network analyzer is Z ₀ , which can be converted. The equation converts the characteristic impedance from Z _C to Z ₀ , thus finding the scattering parameter of the actual object to be tested, and the conversion relation equation is:

among them[ ]and[ ] The transfer matrix before and after the conversion, respectively, is defined as:

It is worth mentioning that in Flow 4, if the reference impedance needs to be converted to the conventional 50Ω (the US National Bureau of Standards develops a standard measurement reference for a 50Ω characteristic impedance transmission line), the characteristic impedance of the transmission line is required, so the To compensate the DC resistance measurement value of the parallel component corrector, the reference impedance of the transmission line is obtained by the following formula, and finally the scattering parameter of the real object to be tested with 50Ω as the reference impedance can be obtained.

Z _C = γ /( j 2 πfC ) (8)

It is worth mentioning that the present invention can utilize the DC resistance measurement value of the offset series component corrector and the offset parallel component corrector to obtain the transmission line propagation constant to solve the self-correction and the low-frequency numerical calculation. The problem is solved by using the offset series element corrector and the high frequency parasitic element y _sp , z _{tp of} the offset parallel element corrector to solve the problem of self-correction numerical calculation when the LINE phase shift is close to 180 degrees and its integral multiple The problem is to achieve broadband correction measurement.

The radio frequency scattering parameter measurement and correction method provided by the invention has the following advantages when compared with other conventional technologies:

1. The present invention is capable of improving the accuracy of scattering parameter measurements and is capable of measuring de-embedding procedures using one-stage semiconductor wafer components or other substrate component RF scattering parameters.

2. The present invention is capable of providing an L-OS-OT correction method to achieve broadband measurement and to utilize the known conditions provided by the corrector to solve for the same or a greater number of unknowns for self-correction purposes.

3. The calibration method used in the present invention has the characteristics of being convenient and simple to manufacture, so that it is not necessary to use an expensive material for fabrication, and it is possible to calibrate to a good bandwidth range by using the characteristics of the resistor series and parallel connection, and all the characteristics. Parameters can be obtained through a self-calibration procedure.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed.

11‧‧‧ Grounding

12‧‧‧ Signal end

2‧‧‧Transmission line segment corrector

21‧‧‧ transmission line

22‧‧‧Transmission line segment

3‧‧‧Series component corrector

31‧‧‧ transmission line

32‧‧‧Receiving transmission line

33‧‧‧ series resistor

4‧‧‧Parallel component corrector

41‧‧‧ transmission line

42‧‧‧Receiving transmission line

43‧‧‧Parallel resistance

5‧‧‧Measurement object measuring device

51‧‧‧ transmission line

52‧‧‧Device under test

1A is a microstrip line layout structure diagram of a radio frequency scattering parameter correction method with three correctors; FIG. 1B is a coplanar waveguide layout structure of a radio frequency scattering parameter correction method with three correctors according to the present invention; FIG. 2 is a circuit diagram of a corrector of a radio frequency scattering parameter correction method with three correctors according to the present invention; FIG. 3 is a flow chart of correcting operation of a radio frequency scattering parameter correction method with three correctors according to the present invention; FIG. 4 is a schematic diagram of a dual-turn network architecture of an overall measurement of a radio frequency scattering parameter correction method with three correctors according to the present invention.

Claims (3)

A radio frequency scattering parameter measurement and correction method with three correctors uses three correctors, one object to be tested, and an arithmetic expression with five variables, wherein the three correctors and the object to be tested The measuring instrument has the same error box, and the scattering parameter matrix of the error box can be obtained by the calibration method, so that the measuring object to be tested is connected to an electronic component to be tested, and the uncorrected measuring data can be performed. Calculate to find the RF scattering parameters of the object under test. A method for correcting radio frequency scattering parameter measurement with three correctors, the steps of the calibration method are: (1) setting a measurement reference impedance of the transmission line to Z _C and setting a self-correction equation with several variables, and the variable system For t ( e ^γl ), z , y , z _tp , y _sp ; (2) with the measurement results of the transmission line segment corrector, the offset series element corrector and the offset parallel element corrector, substituting the five self-correcting equations Using the Newton-Raphson method to find the values of t ( e ^γl ), z , y , z _tp , y _sp ; (3) obtaining the error box and starting the de-embedding procedure; and (4) calculating Z using γ _C , and from Z _C to Z ₀ , perform transmission line reference impedance conversion, and obtain the scattering parameter of the real object to be tested with Z ₀ as the reference impedance reference. The range of the RF patent scattering parameter measurement correction method of item 2, wherein the self-correction system into the equation _{f 1, f 2, f 3} , f 4, f 5, and the f _1, f _2, f ₃ The equations of f ₄ and f ₅ are: