The present invention relates to a high frequency de-embedding method, particularly an on-wafer high frequency de-embedding method, and more particularly a general four-port on-wafer high frequency de-embedding method.
The high frequency characterization measurements, performed on various active and passive electronic devices, semiconductor devices and integrated circuits thereof prepared on a wafer made of silicon and other semiconductor materials, are the basis for device modeling and model parameter extraction and circuit design and evaluation. This high frequency characterization measurement, particularly the high frequency characterization measurement for model parameter extraction of devices, must correspond to specific ports of a device under test (DUT), the locations of which are precisely defined. For this reason, it is necessary to remove all the parasitics, added by instruments, cables, probes and on-wafer testing set-up required to perform the high frequency measurement, from the raw data of the measurement. This is known as the so-called calibration procedure which is a key technique for ensuring accurate extraction of model parameters of high frequency devices.
With regard to the on-wafer high frequency measurement, calibration in a broad sense consists of two steps: off-wafer calibration and on-wafer de-embedding. In the first step, by off-wafer calibration, a test reference plane is moved from vector network analyzer (VNA) to the tip of on-wafer high frequency testing probes by using a set of impendence standard substrate (ISS) calibration dummies (generally made of alumina ceramic substrate). Techniques usually adopted here include short-open-load-thru (SOLT), line-reflect-reflect-match (LRRM), thru-reflect-line (TRL), four-port method (16-term error model), and the like. In the second step, by on-wafer de-embedding, the test reference plane is further shifted to ports of the DUT by using a suite of on-wafer de-embedding dummies. In recent years, a general four-port on-wafer de-embedding method has been proposed to strip the related parasitics of on-wafer measurements. The physical basis of the so-called general four-port method is to describe all the parasitics between the tips of the probes and the ports of the DUT by including them in a general four-port network, the four ports of which are defined at the tips of the probes and the ports of the DUT, respectively.
Y
M
=Y
ee
−Y
ei(YA+Yii)−1Yie (1)
where, YA denotes the Y-parameter 2×2 admittance matrix from P1 to P2, i.e., the intrinsic two-port Y-parameter 2×2 admittance matrix of the DUT; YM denotes the Y-parameter 2×2 admittance matrix from P0 to P3, i.e., the measured whole two-port Y-parameter 2×2 admittance matrix of the DUT including all the on-wafer parasitics; and Yee, Yii, Yei and Yie are four Y-parameter 2×2 admittance sub-matrices of the Y-parameter 4×4 admittance matrix for describing those parasitic four-port network characteristics. Equation (1) is transformed to Equation (2):
Y
A
=−Y
ii
−Y
ie(YM−Yee)−1Yei (2)
As can be seen, YA as the left side of the Equation(2) can be obtained as long as that the right side of Equation (2) is known after the measured value of YM is substituted. That is, the intrinsic high frequency characterization measurement result YA of the DUT is obtained by stripping all the on-wafer parasitics from the raw data of the whole high frequency characterization measurement YM of the DUT, achieving the purpose of the high frequency characterization measurement de-embedding. Therefore, total 16 elements of the four Y-parameter 2×2 admittance matrices Yee, Yii, Yei and Yie for describing said parasitic four-port network need to be determined. A proper equation set, which is composed of equations obtained by applying Equation(1) to a sufficient number of on-wafer de-embedding dummies with both measured YM and theoretical YA known, can be solved for the said 16 matrix element. Accordingly, for the general four-port method, five two-port on-wafer de-embedding dummies are usually adopted, i.e., Open O, Short S, Left L, Right R, and Thru T, the equivalent circuits of which are shown in
Respectively substituting Equations (3)-(7) into Equation (1) obtains an equation set formed of an enough number of equations. After solving said equation set, by using Equation (2), the intrinsic Y-parameter admittance matrix YA of the DUT can be calculated from the measured whole Y-parameter admittance matrix YM of the DUT, i.e., the high frequency de-embedding for stripping said on-wafer parasitics is completed. Specifically, if said parasitic four-port network is passive and contains no any anisotropic material, and further more specifically, if said parasitic four-port network is symmetrical, the number of such on-wafer de-embedding dummies may be decreased to four, even three, as needed. In this way, the complexity and workload of de-embedding related testing structure designs, wafer fabrication, testing and data processing can be effectively decreased.
As described above, said general four-port high frequency de-embedding method is to further shift the test reference planes to input and output ports of the DUT, respectively, on the basis of off-wafer calibration in which the test reference planes are moved from the VNA to the tips of the on-wafer testing probes by using a suite of ISS calibration dummies. Actually, said general four-port high frequency de-embedding method is also suitable for directly moving the test reference planes from VNA to input and output ports of the DUT, without requiring off-wafer calibration based on the ISS calibration dummies, and this is called one-step calibration method. However, in doing this, the premise is that it is necessary to change, in the general four-port network as shown in
The general four-port high frequency de-embedding method has the following advantages: the starting points and end points, from and to which, respectively, the test input and output reference planes need to move, are defined as ports of a general four-port network, respectively, and in this way, all the on-wafer parasitics to be stripped in de-embedding are contained in said general four-port network, without making any assumptions on the specific form of the interior structure of said general four-port network containing all the parasitics, and hence, the universality of said de-embedding technique is ensured. However, a problem with the prior art of said general four-port high frequency de-embedding method is that idealized assumption is made on the network characteristics of the required two-port on-wafer de-embedding dummies, and those idealized on-wafer de-embedding dummies are actually unachievable in reality, and consequently, errors are inevitably introduced. Specifically, this is first manifested in Open and Short dummies. Referring to Equations (3) and (4), ideal Open requires y11=y22=0 for YAO and ideal Short requires y11=y22=∞(infinite) for YAS. Meanwhile, ideal Open and ideal Short further require that there is no any coupling between the input port and the output port, and hence, for both YAO and YAS, y12=y21=0. However, actually, on-wafer Open and Short dummies are non-ideal no matter how they are designed and fabricated. Due to the presence of parasitics (for example, parasitic resistances, parasitic capacitances, parasitic inductances or the like), the admittances (y11 and y22 of YAO) of the actual Open are not equal to 0 and the admittances (y11 and y22 of YAS) of the actual Short are not infinite, either, and also coupling inevitably exists between the input port and the output port of the actual Open and Short dummies, and hence, for both YAO and YAS, y12 and y21 are not strictly equal to 0, either. Secondly, with regard to the Left and Right dummies, the prior art of the general four-port high frequency de-embedding is implemented by connecting conductors GL and GR to the input port and the output port, respectively, on the basis of the Open dummy. Although, as shown in
In order to overcome this problem, the present invention provides an improved general four-port on-wafer high frequency de-embedding method which is still based on the general parasitic four-port theory as described above. However, no idealized lumped assumption is made on the necessary on-wafer de-embedding dummies. Instead, by using the distributive theoretical calculation or simulation results in combination with the corresponding high frequency characterization measurement data, the de-embedding of on-wafer DUT high frequency characterization measurement data is finally completed by optimizing and calibrating corresponding calculation or simulation results. On the basis of inheriting the advantage of the universality the prior art of the general four-port high frequency de-embedding has that all the on-wafer parasitics to be stripped are contained in said general four-port network without any assumption on the specific form of the interior structure of said network, the present invention gives full consideration to the non-ideal nature of the practically fabricated on-wafer de-embedding dummies. No idealized lumped assumption is made on the necessary on-wafer de-embedding dummies as in the prior art, and the universality of the prior art of general four-port high frequency de-embedding is inherited and further developed.
In order to achieve this purpose, a general four-port on-wafer high frequency de-embedding method is provided, including the following steps:
1.1: fabricating, together with a device under test (DUT) to be de-embedded, N on-wafer de-embedding dummies;
1.2: measuring to obtain the whole Y-parameter admittance matrix YM of said DUT and the whole Y-parameter admittance matrix YMj (j=1,2, . . . , N) of each of said on-wafer de-embedding dummies;
1.3: for each on-wafer de-embedding dummy, building a model considering the distributed nature of high frequency characteristics of the on-wafer de-embedding dummy;
1.4: obtaining the intrinsic Y-parameter admittance matrix YAj(pi, p2, . . . pM) (j=1,2, . . . , N) of said N on-wafer de-embedding dummies by calculation or simulation by using said models,
where, p1, p2, . . . , pM are M model parameters of said models on which said calculation or simulation is based, and 4N−16≧M;
1.5: solving an equation set YMj=Yee−Yei (YAj(p1, p2, . . . pM)+Yii)−1Yie(j=1,2, . . . , N) for elements of four sub-matrices Yee Yii, Yei and Yie of the admittance matrix Y of said parasitic four-port network to be stripped in de-embedding and said model parameters p1, p2, . . . , pM as unknowns,
wherein, as shown in the following equation, Yee, Yii, Yei and Yie as four sub-matrices, form the admittance matrix Y of said parasitic four-port network:
1.6: substituting Yee, Yii, Yei and Yie obtained in Step 1.5 and the whole Y-parameter admittance matrix YM of said DUT obtained by measurement in Step 1.2 into Equation YA=Yii−Yie(YM−Yee)−1Yei, to obtain by calculation the intrinsic Y-parameter admittance matrix YA of said DUT.
Solving the equation set YMj=Yee−Yei (YAj(p1, p2, pM)+Yii)−1 Yie (j=1,2, . . . , N) for the elements of four sub-matrixes Yee, Yii, Yei and Yie of the admittance matrix Y of said parasitic four-port network to be stripped in de-embedding and said model parameters p1, p2, . . . , pM as unknowns in Step 1.5 comprises the following steps:
2.1: assigning initial values to said model parameters p1, p2, . . . pM, respectively;
2.2: obtaining the value of YAj(p1, p2, . . . pM)(j=1,2, . . . , N) by calculation or simulation by using the assigned model parameters p1, p2, . . . pM;
2.3: after solving an equation set YMj=Yee−Yei (YAj(p1, p2, . . . pM)+Yii)−1 Yie(j=1,2,3,4) by using the known measured values YMj(j=1,2,3,4) of the first four on-wafer de-embedding dummies and said calculated or simulated values YAj(p1, p2, . . . pM)(j=1,2,3,4) to obtain the values of Yee, Yii, Yei and Yie, substituting the known measured values YMj(j=5,6, . . . , N) of the remaining on-wafer de-embedding dummies and said solved values of Yee, Yii, Yei and Yie, into YDj=−Yii−Yie (YMj−Yee)−1Yei (j=5,6, . . . , N) to obtain by calculation the de-embedded Y-parameter admittance matrices YDj(j=5,6, . . . , N) of said remaining on-wafer de-embedding dummies;
2.4: comparing the calculated YDj(j=5,6, . . . , N) with the calculated or simulated values YAj(p1, p2, . . . pM)(j=5,6, . . . , N) of the corresponding remaining on-wafer de-embedding dummies already obtained in Step 2.2,
determining final values for said undetermined model parameters p1, p2, . . . pM which are necessary for the calculation or simulation of the on-wafer de-embedding dummies, if a difference between the two meets the set error standard, and
correcting the values of the said model parameters p1, p2, . . . pM and reassigning them, respectively, and then turning back to Step 2.2, if the difference between the two does not meet the set error standard.
In order to achieve this purpose, a general four-port on-wafer high frequency de-embedding method for the four-port network of passivity, reciprocity and symmetry is provided, including the following steps:
3.1: fabricating, together with a device under test (DUT) to be de-embedded, N on-wafer de-embedding dummies of passivity, reciprocity and symmetry;
3.2: measuring to obtain the whole Y-parameter admittance matrix YM of said DUT and the whole Y-parameter admittance matrix YMj (j=1,2, . . . , N) of each of said on-wafer de-embedding dummies;
3.3: for each on-wafer de-embedding dummy, building a model considering the distributed nature of high frequency characteristics of the on-wafer de-embedding dummy;
3.4: obtaining the intrinsic Y-parameter admittance matrices YAj(p1, p2, . . . pM) (j=1,2, . . . , N) of said N on-wafer de-embedding dummies by calculation or simulation by using said models,
where, p1, p2, . . . , pM are M model parameters of models on which said calculation or simulation is based, and 2N−6≧M;
3.5: solving an equation set YMj=Yee−Yei(YAj(p1, p2, . . . pM)+Yii)−1Yei(j=1,2, . . . , N) for the elements of the three sub-matrices Yee, Yii and Yei of the admittance matrix Y of said parasitic four-port network to be stripped in de-embedding and said model parameters p1, p2, . . . , pM as unknowns,
wherein, as shown in the following equation, Yee, Yii, and Yei, as three sub-matrices, form the admittance matrix Y of said parasitic four-port network:
and
3.6: substituting Yee, Yii and Yei obtained in Step 3.5 and the whole Y-parameter admittance matrix YM of said DUT obtained by measurement in Step 3.2 into Equation YA=−Yii−Yei (YM−Yee)−1Yei, to obtain by calculation the intrinsic Y-parameter admittance matrix YA of said DUT.
Solving the equation set YMj=Yee−Yei(YAj(p1, p2, . . . pM)+Yii)−1 Yei (j=1,2, . . . , N) for the elements of the three sub-matrices Yee, Yii and Yei of the admittance matrix Y of said parasitic four-port network to be stripped in de-embedding and said model parameters p1, p2, . . . , pM as unknowns in Step 3.5 comprises the following steps:
4.1: assigning initial values to said model parameters p1, p2, . . . pM, respectively;
4.2: obtaining the values of YAj(p1, p2, . . . pM)(j=1,2, . . . , N) by calculation or simulation by using the assigned model parameters p1, p2, . . . pM;
4.3: after solving an equation set YMj=Yee−Yei(YAj(p1, p2, . . . pM)+Yii)−1 Yei (j=1,2,3) by using the known test values YMj(j=1,2,3) of the first three on-wafer de-embedding dummies and said calculated or simulated values YAj(p1, p2, . . . pM) (j=1,2,3) to obtain the values of Yee, Yii and Yei (it is unnecessary to completely solve Yei, referring to claim 5.4), substituting the known test values YMj(j=4,5, . . . , N) of the remaining on-wafer de-embedding dummies and said obtained values of Yee, Yii and Yei into YDj=−Yii−Yei(YMj−Yee)−1Yei (j=4,5, . . . , N) to obtain by calculation the de-embedded Y-parameter admittance matrices YDj(j=4,5, . . . , N) of said remaining on-wafer de-embedding dummies;
4.4: comparing the calculated YDj(j=4,5, . . . , N) with the calculated or simulated values YAj(p1, p2, . . . pM)(j=4,5, . . . , N) of the corresponding remaining on-wafer de-embedding dummies already obtained in Step 4.2, determining final values for undetermined model parameters p1, p2, . . . pM which are necessary for the calculation or simulation of the on-wafer de-embedding dummies, if a difference between the two meets the set error standard, and
correcting the values of the model parameters p1, p2, . . . pM and reassigning them, and then turning back to Step 4.2, if the difference between the two does not meet the set error standard.
Solving the equation set YMj=Yee−Yei(YAj(p1, p2, . . . pM)+Yii)−1Yie (j=1,2,3) to further obtain by calculation the de-embedded Y-parameter admittance matrices YDj(j=4,5, . . . , N) of said remaining on-wafer de-embedding dummies in Step 4.3 comprises the following steps:
5.1: obtaining by calculation matrices Z2A=(YA2−YA1)−1, Z2M=(YM2−YM1)−1, Z3A=(YA3−YA1)−1 and Z3M=(YM3−YM1)−1, where exponent −1 represents matrix inversion;
5.2: calculating quantities
xp=r2p(yp+yA111+yA112)(yp+yA211+yA212) and xm=r2m(ym+yA111−yA112)(ym+yA211−yA212), where z2A11 and z2A12 are respectively z11 and z12 of Z2A; z2M11 and z2M12 are respectively z11 and z12 of Z2M; z3A11 and z3A12 are respectively z11 and z12 of Z3A; z3M11 and z3M12 are respectively z11 and z12 of Z3M; yA111 and yA112 are respectively y11 and y12 of YA1; yA211 and yA212 are respectively y11 and y12 of YA2; yA311 and yA312 are respectively y11 and y12 of YA3;
5.3: calculating quantities
to obtain the matrix
5.4: obtaining by calculation the square of elements y11 and y12 of the matrix Yei:
where the plus-minus sign is selected such that, at the low frequency limit, yei112 tends to infinity and yei122 tends to zero, and both yei112 and yei122 continuously vary with frequency;
5.5: obtaining by calculation a matrix ZAi=(YA1+Yii)−1;
5.6: calculating quantities
to obtain a matrix
where zAi11 and zAi12 are respectively z11 and z12 of ZAi;
5.7: obtaining by calculation the matrix Yee=YM1+YAi;
5.8: obtaining by calculation a matrix ZMej=(Yee−YMj)−1(j=4,5, . . . , N);
5.9: calculating quantities
to obtain a matrix
where zMej11, zMej12, zMej21 and zMej22 are respectively z11, z12, z21 and z22 of ZMej; and
5.10: obtaining by calculation the de-embedded Y-parameter matrix YDj=YMej−Yii(j=4,5, . . . , N) of said remaining on-wafer de-embedding dummies.
Calculating the intrinsic Y-parameter admittance matrix YA of said DUT by using the whole Y-parameter admittance matrix YM of said DUT obtained by measurement in Step 3.6 comprises the following steps:
6.1: obtaining by calculation a matrix ZMe=(Yee−YM)−1;
6.2: calculating quantities
to obtain a matrix
where zMe11, zMe12, zMe21 and zMe22 are respectively z11, z12, z21 and z22 of ZMe; and
6.3: obtaining by calculation the intrinsic Y-parameter admittance matrix YA=YMe−Yii of said DUT to be de-embedded.
On the basis of inheriting such a universality that the existing technology of universal four-port high frequency de-embedding contains all parasitic parameters to be stripped in said universal four-port network without any assumption on the specific form of the interior structure of said network, the present invention gives full consideration to the non-ideal essence of the practically needed de-embedding co-testing structures. No lumped and idealized assumption is made on the necessary de-embedding co-testing structures as in the prior art, and the universality of the existing technology of universal four-port high frequency de-embedding is inherited and further developed.
Implementation 1: one implementation of a general four-port on-wafer high frequency de-embedding method for a case in which parasitics to be stripped form a general parasitic four-port network
(1) Five on-wafer de-embedding dummies are designed and fabricated together with a device under test (DUT) to be de-embedded, i.e., five on-wafer de-embedding two-port dummies generally adopted in the prior art of the general four-port on-wafer high frequency de-embedding method, including: Open (O), Short (S), Left (L), Right (R) and strip-line Thru (T). However, no assumption is made on the form of their equivalent circuits as in
(2) By an on-wafer high frequency measurement instruments and techniques, the whole Y-parameter admittance matrix YM of said DUT and the whole Y-parameter admittance matrices, which are respectively denoted by YMO, YMS, YML, YMR and YMT, of said five on-wafer de-embedding dummies are obtained by measurement.
(3) In the premise of giving consideration to the distributive nature of high frequency characteristics of said on-wafer de-embedding dummies, models for said Open (O), Short (S), Left (L), Right (R) and Thru (T) are built in a passive electromagnetic field simulation software environment, respectively, according to structures as shown in
(4) An equation set YMj=Yee−Yei (YAj(σ, ∈r)+Yii)−1Yie (j=O,S,L,R,T) is solved for the elements of the related admittance matrixes Yee, Yii, Yei and Yie of the parasitic four-port network to be stripped in de-embedding and said model parameters σ and ∈r as unknowns. Specifically, the following steps are included:
(4-1) on the basis that initial default values are taken for the model parameters σ and ∈r respectively, obtaining the values of YAj(σ, ∈r)(j=O, S, L, R, T) by passive electromagnetic field simulation;
(4-2) after solving an equation set YMj=Yee−Yei(YAj(σ, ∈r)+Yii)−1Yie (j=O, S, L, R) by using the known measurement values YMj (j=O, S, L, R) of the first four on-wafer de-embedding dummies and said simulated values YAj(σ,∈r)(j=O,S, L, R) to obtain the values of Yee, Yii, Yei and Yie, substituting the known measurement values YMT of the strip-line Thru T and said obtained values of Yee, Yii, Yei and Yie into YDT=−Yii−Yie(YMT−Yee)−1Yei to obtain by calculation the de-embedded Y-parameter admittance matrix YDT of the strip-line Thru T;
(4-3) comparing the calculated YDT with the simulated value YAT(σ, ∈r) of the strip-line Thru T already obtained in Step (4-1), properly correcting the values of the model parameters σ and ∈r and then turning back to Step (4-1) if the difference between the two does not meet the set error standard, and obtaining the values of YAj(σ,∈r)(j=O, S, L, R, T) again by passive electromagnetic field simulation by using the corrected model parameters; and
(4-4) once turning back to Step (4-1), starting a cyclic iterative fitting process from Step (4-1) to Step (4-3), performing iterative optimization fitting by optimization algorithms such as inverse modeling, and continuously correcting the values of the model parameters σ and ∈r used for simulation of intrinsic Y-parameter admittance matrices of the on-wafer de-embedding dummies until a difference between the de-embedded Y-parameter admittance matrix YDT of the strip-line Thru T and the corresponding simulated value YAT (σ, ∈r) meets a set error standard, that is, determining the final values for the undetermined mode parameters σ and ∈r which are necessary for the simulation of the on-wafer de-embedding dummies by this iterative fitting between YDT and YAT (σ, ∈r).
(5) The solved Yee, Yii, Yei and Yie and the whole Y-parameter admittance matrix YM of said DUT obtained by measurement are substituted into the right side of YA=−Yii−Yie(YM−Yee)−1Yei to complete said general four-port on-wafer high frequency de-embedding. That is, the intrinsic Y-parameter admittance matrix YA of said DUT is calculated by using the whole Y-parameter admittance matrix YM of said DUT obtained by measurement.
Implementation 2: one implementation of a general four-port on-wafer high frequency de-embedding method for a case in which all the on-wafer parasitics to be stripped form a parasitic four-port network of passivity, reciprocity and symmetry.
(1) Four on-wafer strip-line Thru de-embedding dummies of passivity, reciprocity and symmetry and different in width are designed and fabricated together with a device under test (DUT) to be de-embedded, i.e., Thru 1, Thru 2, Thru 3 and Thru 4 which are respectively denoted by T1, T2, T3 and T4. Their schematic structure diagrams are respectively as shown in
(2) By using on-wafer high frequency measurement instruments and techniques, the whole Y-parameter admittance matrix YM of said DUT and the whole Y-parameter admittance matrices YMj (j=1,2,3,4) of said four on-wafer strip-line Thru de-embedding dummies are obtained by measurement.
(3) In the premise of giving consideration to the distributive nature of high frequency characteristics of said on-wafer de-embedding dummies, analytical models for said four on-wafer strip-line Thru de-embedding dummies are built, respectively, and following intrinsic Y-parameter admittance matrices of said four Thru de-embedding dummies are calculated by the built models:
where, σ and ∈r, as model parameters of models on which said calculation is based, are respectively the conductivity of metals in the on-wafer Thru de-embedding dummies and the relative dielectric constant of the dielectric material, μ0=4π×10−7H/m is the permeability of vacuum, f is the frequency of test and simulation, and c=3×108 m/s. is the speed of light in vacuum.
(4) An equation set YMj=Yee−Yei(YAj(σ, ∈r)+Yii)−1Yei(j=1,2,3,4) is solved for the elements of the related admittance matrixes Yee, Yii and Yei of the parasitic four-port network to be stripped in de-embedding and said model parameters σ and ∈r as unknowns. Specifically, the following steps are included:
(4-1) on the basis that the initial default values are taken for the model parameters σ and ∈r respectively, obtaining the values of YAj(σ, ∈r)(j=1,2,3,4) by calculation;
(4-2) after solving an equation set YMj=Yee−Yei(YAj(σ,∈r)+Yii)−1Yei (j=1,2,3) by using the known measurement values YMj (j=1,2,3) of the three de-embedding dummies T1, T2 and T3 and said calculated values YAj(σ,∈r)(j=1,2,3) to obtain the values of Yee, Yii and Yei (it is unnecessary to completely solve Yei, as long as the square of its elements is obtained), substituting the known measurement value YM4 of the T4 de-embedding dummy and said obtained values of Yee, Yii and Yei into the right side of YD4=−Yii−Yei(YM4−Yee)−1Yei to obtain by calculation the de-embedded Y-parameter admittance matrix YD4 of the T4 de-embedding dummy, specifically including the following steps:
(4-2-1) obtaining by calculation matrices Z2A=(YA2−YA1)−1, Z2M=(YM2−YM1)−1, Z3A=(YA3−YAj)−1 and Z3M=(YM3−YM1)−1, where exponent −1 represents matrix inversion;
(4-2-2) calculating quantities
where z2A11 and z2A12 are respectively z11 and z12 of Z2A; z2M11 and z2M12 are respectively and z11 and z12 of Z2M; z3A11 and z3A12 are respectively z11 and z12 of Z3A; z3M11 and z3M12 are respectively z11 and z12 of Z3M; yA111 and yA112 are respectively y11 and y12 of YA1; yA211 and yA212 are respectively y11 and y12 of YA2, yA311 and yA312 are respectively y11 and y12 of YA3;
(4-2-3) calculating quantities
to obtain the matrix
(4-2-4) obtaining by calculation the square of elements y11 and y12 of the matrix
where the plus-minus sign is selected such that, at the low frequency limit, yei112 tends to infinity and yei122 tends to zero, and both yei112 and yei122 continuously vary with frequency;
(4-2-5) obtaining by calculation a matrix ZAj=(YA1+Yii)−1;
(4-2-6) calculating quantities
to obtain a matrix
where zAi11 and zAi12 are respectively z11 and z12 of ZAi;
(4-2-7) obtaining by calculation the matrix Yee=YM1+YAi;
(4-2-8) obtaining by calculation a matrix ZMe4=(Yee−YM4)−1;
(4-2-9) calculating quantities
to obtain a matrix
where zMe411, zMe412, zMe421 and zMe422 are respectively z11, z12, z21 and z22 of ZMe4;
(4-2-10) obtaining by calculation the de-embedded Y-parameter matrix YD4=YMe4 Yii of the T4 de-embedding dummy;
(4-3) comparing the calculated YD4 with the simulated value YA4 (σ, ∈r) of the T4 de-embedding dummy already obtained in Step (4-1), properly correcting the values of the model parameters σ and ∈r and then turning back to Step (4-1) if the difference between the two does not meet the set error standard, and obtaining the values of YAj(σ,∈r)(j=1,2,3,4) again by calculation by using the corrected model parameters; and
(4-4) once turning back to Step (4-1), starting a cyclic iterative fitting process from Step (4-1) to Step (4-3), performing iterative optimization fitting by a trial and error method, and continuously correcting the values of the model parameters σ and ∈r used for calculation of intrinsic Y-parameter admittance matrices of the de-embedding dummies until a difference between the de-embedded Y-parameter admittance matrix YD4 of the T4 de-embedding dummy and a corresponding calculated value YA4(σ, ∈r) meets the set error standard, that is, determining the final values for the undetermined mode parameters σ and ∈r which are necessary for the calculation of the de-embedding dummies by this iterative fitting between YD4 and YA4(σ,∈r).
(5) The Yee, Yii and Yei (actually, it is unnecessary to completely determine a specific value for all elements in Yei, as long as the square of the elements is determined) solved in Step (4) and the whole Y-parameter admittance matrix YM of said DUT obtained by measurement in Step (2) are substituted into the right side of YA=−Yii−Yei (YM−Yee)−1Yei to complete said general four-port on-wafer high frequency de-embedding of the parasitic four-port network, to be stripped, of passivity, reciprocity and symmetry. That is, the intrinsic Y-parameter admittance matrix YA of said DUT is calculated by using the whole Y-parameter admittance matrix YM of said DUT obtained by measurement. Specifically, the following steps are included:
(5-1) obtaining by calculation a matrix ZMe=(Yee−YM)−1;
(5-2) calculating quantities
to obtain a matrix
where zMe11, zMe12, zMe21 and ZMe22 are respectively z11, z12, z21 and z22 of ZMe; and
(5-3) obtaining by calculation the intrinsic Y-parameter admittance matrix YA=YMe−Yii of said DUT to be de-embedded.
The foregoing descriptions are merely preferred embodiments of the present invention and the protection scope of the present invention is not limited thereto. Any changes or replacements that readily occur to those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention. Hence, the protection scope of the present invention should be subject to the protection scope defined in the claims.
Number | Date | Country | Kind |
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2016101930008.3 | Mar 2016 | CN | national |