JP3492883B2 - High frequency measurement board - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency measurement used for measuring electrical characteristics of a semiconductor device using a microstrip line, a semiconductor device housing package, or a circuit board at a high frequency band such as a microwave band or a millimeter wave band. More specifically, the present invention relates to a wide-band, low-loss high-frequency measurement substrate with an improved measurable frequency band.

[0002]

2. Description of the Related Art In measuring and evaluating the electrical characteristics of a semiconductor element or a package / circuit board for storing a semiconductor element in a high frequency band such as a microwave band or a millimeter wave band,
On the measuring instrument side, a wafer probe is used which enables high-accuracy measurement by contact with the coplanar line. On the other hand, the transmission line of the input / output part on the DUT side such as a high-speed digital circuit for a wireless communication device using a high-frequency signal or a high-frequency circuit or a high-frequency semiconductor element or a high-frequency semiconductor element housing package that accommodates it is a micro Strip lines are common. For this reason, it is necessary to provide a line conversion unit for connecting the coplanar line of the wafer probe and the microstrip line of the DUT in order to measure the electrical characteristics at a high frequency using the wafer probe. Requires high-frequency transmission with low loss in order to extract the characteristics of the DUT with high accuracy.

Conventionally, as the structure of the line converting portion, generally, the signal conductor width and the ground conductor width of the coplanar line portion are appropriately designed so as to correspond to the size required by the head of the wafer probe, and one end thereof and a micro One end of the strip line is connected so that the mutual signal conductor width changes smoothly, and the ground (ground) conductor of the coplanar line is connected to the ground conductor on the back surface of the microstrip line and a through conductor such as a through hole or via hole. It was configured to connect.

For example, as shown in a plan view of an example of a structure of a conventional line conversion portion in FIG. 12, a dielectric substrate 1 having a relative permittivity of 9.6.
A conductor film is formed on almost the entire back surface of the substrate to form a ground conductor, and the width of the signal conductor 2 in the microstrip line section is set to 190.
μm, the width of the signal conductor 3 in the coplanar line portion is 160 μm,
Signal conductor 3 and ground conductors 4 and 4'of the coplanar line section
And the ground conductors 4 and 4'of the coplanar line section are electrically connected to the ground conductor on the rear surface through through holes 5 and 5'each having a diameter of 150 μm and are through conductors. Is used. Then, when the ground conductors of the coplanar line portion having the through-hole pad structure are made to have the same shape and are mirror-symmetrically opposed to each other through the microstrip line portion, the electrical characteristics are extracted by measurement, and the diagram is shown in FIG. The frequency characteristic as shown by is obtained.

In FIG. 13, the horizontal axis represents frequency (unit: GH
z), the vertical axis represents the transmission coefficient (unit: dB) as an evaluation index of the transmitted amount of the input signal, and the characteristic curve represents the frequency characteristic of the transmission coefficient. From this result, the transmission coefficient decreases as the frequency increases,
It can be seen that the amount of signal transmission decreases.

[0006] Further, as described above, a utility model registration No. 2507797 "Microstrip" is used in which a coplanar line and a microstrip line are line-converted without using a through conductor such as a through hole or a via hole to constitute a high frequency measurement substrate. There is a line circuit measurement jig. According to the publication, as shown in a plan view in FIG. 14, the measuring jig (measuring substrate) 10 has a step-like end of a microstrip line 12 on a dielectric substrate 11 having a ground conductor on the back surface. Alternatively, the probe head 13 may be formed in a tapered shape and its width
Corresponding to the center conductor width of the probe head. Also, an equivalent ground is formed by a radial stub 14 in the shape of a semi-circle or a semi-circle near the tip to correspond to the conductors of the two ground lines of the probe head 13. Let and radial stub
The configuration was such that the stub radius of 14 was an effective length of about 1/2 wavelength of the lower limit of the measurement frequency.

According to this structure, since the variable elements such as the ribbon bonding and the above-mentioned through conductor do not intervene in the connection between the probe head 13 and the measuring jig 10, good reproducibility of measured data can be obtained. Is to be done.

This semicircular or fan-shaped radial stub 14
It can be said that the principle of the equivalent ground by is equivalent to the general phenomenon of radial stub in a high frequency circuit.

That is, this content is IEEE TRANSACTIONS
ON MICROWAVE THEORY AND TECHNIQUES, VOL.36, NO.7,
JULY 1988 "A Coplanar Probe to Microstrip Transit
Based on “ion”, the reactance value X of the radial stub 15 having the shape shown in the plan view of FIG. 15 is calculated by calculating the thickness h of the substrate on which the radial stub 15 is formed, the inner diameter r _{1 of the} radial stub 15, and the outer diameter. Radius r ₂ · Radial central angle θ · Effective relative permittivity ε _re when propagating radial in the radial direction · Free space wavelength λ ₀

[0010]

[Equation 1]

[0011]

[Equation 2]

[0012]

[Equation 3]

[0013]

[Equation 4]

[0014]

[Equation 5]

Where J _i (x) and N _i (x) are i
Here is the Bessel function

On the basis of such a principle, the radial stub has an effect that it can be regarded as an equivalent ground because the operation at high frequency is close to a perfect reflection state, so that it can be applied as an equivalent ground on a high frequency measuring substrate. The radial stub 14 of utility model registration No. 2507797 uses such an effect.

Next, the characteristics of the high-frequency measuring substrate formed by such radial stubs are extracted.

FIG. 9 is a plan view showing an example of a conventional substrate for high frequency measurement using a radial stub. A metal film as a ground conductor is deposited on almost the entire back surface of a dielectric substrate 21 having a relative permittivity of 9.6. The signal conductor 22 of the microstrip line and the signal conductors 23 and 23 'of the coplanar line are formed on the surface, and the ground conductors 24 and 24' of the coplanar line are formed.
Installed at a distance of 135 μm from 23 ・ 23 'and ground conductor
24 and 24 'each have an inner diameter of 215 μm and an outer diameter of 580 μm
It is formed as a fan-shaped radial stub with a central angle of 230 °. When the electrical characteristics of this high frequency substrate were extracted by measurement, the results shown in the diagrams of FIGS. 10 and 11 were obtained.

In FIG. 10, the horizontal axis represents frequency (unit: GH
z), the vertical axis represents the reflection coefficient (unit: dB) as an evaluation index of the reflected amount in the input signal, the solid line in the characteristic curve represents the simulation result, and the broken line represents the measured value. Shown respectively.

Further, in FIG. 11, the horizontal axis represents the frequency (unit: GHz), and the vertical axis represents the transmission coefficient (unit: dB) as an evaluation index of the transmitted amount of the input signal. The solid line in the curve shows the simulation result,
The broken lines indicate the measured values. From these results, it can be seen that by using the radial stub as an equivalent ground, a high frequency measurement substrate having a low loss transmission frequency band characteristic can be obtained.

[0021]

However, in the conventional substrate for high frequency measurement as described above, when a through conductor such as a through hole or a via hole as shown in FIG. Furthermore, as a result of the ground component becoming unstable due to the inductance component of the through conductor in the high frequency band of the millimeter wave band, discontinuity of the characteristic impedance occurs, reflection increases with respect to the incident signal, and the amount of transmission of the high frequency signal increases. There was a problem of decrease. In addition, there is a problem that it is difficult to manufacture the high frequency measurement substrate with high accuracy because the through conductor processing step is required.

Further, as shown in FIG. 14 and FIG. 9, when an equivalent gland with a semi-circular or fan-shaped radial stub is used, the semi-circular or fan-shaped radial gland has a circumferential center of a substantially central position. At a frequency whose length corresponds to the effective length of one wavelength, the charge distribution in the circumferential direction becomes a standing distribution in which the density becomes higher at the end portions and the intermediate portion in the semicircular or fan-shaped circumferential direction, resulting in resonance. There was a problem that was caused. For this reason, the effect of the equivalent ground hardly occurs in the vicinity of this resonance frequency, and as a result, the characteristic impedance becomes discontinuous, so that the reflection with respect to the incident signal increases and the transmission amount of the high frequency signal decreases. There was a problem. Further, when the resonance frequency is a frequency in or near the low-frequency transmission frequency band, there is a problem that the measurable frequency band is narrowed.

The present invention has been made in view of the above problems in the prior art, and an object of the present invention is to provide a high-frequency measurement substrate using a radial stub as an equivalent ground so that the resonance frequency of the radial stub is on the low frequency side. The purpose of the present invention is to provide a substrate for high frequency measurement in which the low-loss transmission frequency band is widened by moving to low temperature.

[0024]

According to a first aspect of the present invention, there is provided a high frequency measuring substrate in which a ground conductor is formed on substantially the entire lower surface of a dielectric substrate, and a signal conductor of a microstrip line and the signal conductor are formed on the upper surface. A semicircular or fan-shaped radial stub-shaped equivalent ground conductor provided in the vicinity of the tip of the signal conductor and the ground conductor of the coplanar line structure wafer probe, respectively. A high-frequency measurement substrate for electrically connecting
It is characterized in that a conductor non-forming region along the radial direction is provided in a part of the equivalent ground conductor.

A high frequency measuring substrate according to claim 2 of the present invention is the high frequency measuring substrate according to claim 1, wherein
The radial length of the conductor non-forming region is set to be at least half the radial width of the equivalent ground conductor.

A high frequency measurement board according to a third aspect of the present invention is the high frequency measurement board according to the first or second aspect, wherein the conductor non-formation region is substantially the center angle of the equivalent ground conductor. It is characterized in that it is arranged at a position of a quarter and / or approximately three quarters.

A high frequency measuring board according to a fourth aspect of the present invention is the high frequency measuring board according to any one of the first to third aspects, wherein one end in a radial direction of the conductor non-forming region is the equivalent ground conductor. It is characterized in that it is opened to the inner or outer circumference.

[0028]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, there is provided an equivalent ground conductor on the upper surface of a dielectric substrate for contacting and electrically connecting with a ground conductor of a wafer probe having a coplanar line structure. Is formed in a semicircular or fan-shaped radial stub shape, and a conductor non-forming area, which is a portion in which a conductor is not formed along the radial direction, is provided in a part of its equivalent ground conductor. A stationary charge density distribution in the circumferential direction is generated at a frequency on the lower frequency side as compared with the case where the conductor non-forming region is not provided.

Therefore, in a conventional radial stub-shaped equivalent ground conductor, there is a low loss transmission of a frequency whose semicircular or fan-shaped radial center substantially corresponds to the effective length of one wavelength in the circumferential direction. Compared to the case where the charge distribution in the circumferential direction when the frequency is within the frequency band becomes a standing distribution in which the density becomes higher at the circumferential end and the middle part of the semicircle or fan shape and resonance occurs. Then, the resonance frequency can be moved to the low frequency side of the low loss transmission frequency band. As a result, the low-loss transmission frequency band is widened, so that the high-frequency measurement substrate has a wide-band, low-loss characteristic.

According to a second aspect of the present invention, there is provided a high frequency measuring substrate according to the first aspect, wherein the radial length of the conductor non-forming region is a semicircular or fan-shaped radial stub. Since the radial equivalent of the ground conductor has a width equal to or more than half the radial width of the equivalent ground conductor, the circumferential static charge density distribution of the equivalent ground conductor in the radial stub shape is compared to the case where no conductor-free area is provided. Then, it effectively occurs at the lower frequency side. for that reason,
In a radial stub-shaped equivalent ground conductor as in the conventional case, a frequency within a transmission frequency band with low loss is a frequency in which the circumferential length of the semicircular or fan-shaped radial center corresponds to the effective length of one wavelength. When the electric charge distribution in the circumferential direction becomes semi-circular or fan-shaped, the resonance frequency becomes higher than the density at the end and the middle in the circumferential direction. Can be moved to the low frequency side of the low loss transmission frequency band. As a result, the low-loss transmission frequency band is widened, so that the high-frequency measurement substrate has a wide-band, low-loss characteristic.

According to a third aspect of the high frequency measurement board of the present invention, in the high frequency measurement board according to the first or second aspect, in the radial stub-shaped equivalent ground conductor in the conductor non-formation region. The position in the circumferential direction is about a quarter or about a third of the central angle of the semicircle or fan shape,
Alternatively, by arranging so as to be at positions of approximately ¼ and approximately ¾, a semicircular or fan-shaped circumferential charge density distribution in the radial stub-shaped equivalent ground conductor occurs. The frequency is efficiently generated on the lower frequency side as compared with the case where the conductor non-forming region is not provided. Therefore, in a radial stub-shaped equivalent grounding conductor as in the conventional case, a semicircular or fan-shaped radial center has a circumferential length at a substantially central position corresponding to an effective length of one wavelength. When the frequency becomes, the charge distribution in the circumferential direction becomes a standing distribution in which the density becomes high at the end portions and the intermediate portion in the semicircular or fan-shaped circumferential direction, and compared with the case where resonance occurs, The resonance frequency can be moved to the low frequency side of the low loss transmission frequency band. As a result, the low-loss transmission frequency band is widened, so that the high-frequency measurement substrate has a wide-band, low-loss characteristic.

According to a fourth aspect of the present invention, there is provided a high frequency measuring substrate according to any one of the first to third aspects, wherein one end of the conductor non-forming region is a radial stub-shaped equivalent ground. The cutout shape is opened on the inner or outer circumference of the conductor, so that the frequency at which a semicircular or fan-shaped circumferential charge density distribution is generated in the radial stub-shaped equivalent ground conductor does not form the conductor. Compared with the case where no region is provided, it occurs more efficiently on the low frequency side. Therefore, in a radial stub-shaped equivalent grounding conductor as in the conventional case, a semicircular or fan-shaped radial center has a circumferential length at a substantially central position corresponding to an effective length of one wavelength. When the frequency becomes, the charge distribution in the circumferential direction becomes a standing distribution in which the density becomes high at the end portions and the intermediate portion in the semicircular or fan-shaped circumferential direction, and compared with the case where resonance occurs, The resonance frequency can be moved to the low frequency side of the low loss transmission frequency band. As a result, the low-loss transmission frequency band is widened, so that the high-frequency measurement substrate has a wide-band, low-loss characteristic.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a plan view showing an example of an embodiment of a high frequency measuring substrate of the present invention.

In FIG. 1, 31 is a dielectric substrate in which a ground conductor is formed on substantially the entire back surface (lower surface), and 32 is a signal of a microstrip line formed on the front surface (upper surface) of the dielectric substrate 31. It is a conductor. Reference numeral 33 denotes a signal conductor of the coplanar line portion, which is electrically connected to the signal conductor 32 of the microstrip line and forms the tip of the signal conductor 32, and is a signal conductor of a wafer probe (not shown) having a coplanar line structure. Corresponds to the portion for contacting and electrically connecting to the signal conductor 32 of the microstrip line.

34 is a signal conductor 32 of the microstrip line
Is an equivalent grounding conductor provided in the vicinity of the tip of, and is formed by a semi-circular or fan-shaped radial stub-shaped conductor pattern. The shape, size, position, etc. of this equivalent ground conductor 34 are set in the same manner as in the conventional radial stub, and both ends are matched with the tip shape of the signal conductor 32 of the microstrip line so as to satisfy desired high-frequency characteristics. It is appropriately set by extending it.

35 and 35 'are equivalent ground conductors 34
Is a conductor non-formation region that is provided in a portion along the radial direction. Here, the conductor non-forming regions 35 and 35 'are provided on the inner circumference of the radial stub-shaped equivalent ground conductor 34 with one end in the radial direction open, and in the circumferential direction, the center of the equivalent ground conductor 34 is formed. An example is shown in which they are arranged at positions of about 1/4 and about 3/4 of a corner.

The size, shape, position, etc. of the equivalent ground conductor 34 are appropriately set so as not to adversely affect the high frequency and to generate a stationary charge density distribution at the low frequency side of the transmission frequency band. For example, since the high-frequency coupling with the grounding conductor on the back surface is made as strong (as many) as possible to obtain a wide band, a large radial angle is obtained,
The width is made shorter than the length in the radial direction so that the shape is along the radial direction.

In this way, for example, by providing the slit-shaped conductor non-forming region, the path of the current flowing from one end to the other in the circumferential direction of the radial becomes long, and the frequency corresponding to one wavelength becomes low. , The frequency at which the charge density distribution on the radial stub becomes a stationary distribution moves to the lower frequency side. However, since the charge density distribution becomes a standing distribution, it is most effective to provide the conductor non-formation region at a location where the current density is high.

FIG. 2 is a plan view showing another example of the embodiment of the high frequency measuring substrate of the present invention.

In FIG. 2, reference numeral 41 is a dielectric substrate having a ground conductor formed on the substantially entire lower surface thereof, and 42 is a dielectric substrate 41.
Is formed on the upper surface of the microstrip line, 43 is a signal conductor of the coplanar line portion, and is electrically connected to the signal conductor 42 of the microstrip line to form the tip of the signal conductor 42. This corresponds to a portion where a signal conductor of a wafer probe (not shown) having a line structure is brought into contact with and electrically connected to the signal conductor 42 of the microstrip line.

Reference numeral 44 is a signal conductor 42 of the microstrip line.
Is an equivalent grounding conductor provided in the vicinity of the tip of, and is formed by a semi-circular or fan-shaped radial stub-shaped conductor pattern. The shape, size, position, etc. of the equivalent ground conductor 44 are also appropriately set as in the above.

45 and 45 'are equivalent ground conductors 44
Is a conductor non-formation region that is provided in a portion along the radial direction. Here, the conductor non-formation regions 45 and 45 'are provided on the outer circumference of the radial stub-shaped equivalent ground conductor 44 with one end in the radial direction opened, and the center angle of the equivalent ground conductor 44 is arranged in the circumferential direction. 2 shows an example in which they are arranged at positions of about 1/4 and about 3/4.

FIG. 3 is a plan view showing still another example of the embodiment of the high frequency measuring substrate of the present invention.

In FIG. 3, reference numeral 51 is a dielectric substrate having a ground conductor formed on the entire lower surface thereof, and 52 is a dielectric substrate 51.
The signal conductor of the microstrip line formed on the upper surface of the signal conductor 53 is the signal conductor of the coplanar line portion, and is electrically connected to the signal conductor 52 of the microstrip line to form the tip of the signal conductor 52. This corresponds to a portion where a signal conductor of a wafer probe (not shown) having a line structure is brought into contact with and electrically connected to the signal conductor 52 of the microstrip line.

54 is the signal conductor 52 of the microstrip line
Is an equivalent grounding conductor provided in the vicinity of the tip of, and is formed by a semi-circular or fan-shaped radial stub-shaped conductor pattern. The shape, size, position, etc. of the equivalent ground conductor 54 are also appropriately set as in the above.

55 and 55 'are equivalent ground conductors 54
Is a conductor non-formation region that is provided in a portion along the radial direction. Here, the conductor non-forming regions 55 and 55 'are provided at substantially the center of the radial stub-shaped equivalent ground conductor 54 in the radial direction, and the equivalent ground conductor 54 is arranged in the circumferential direction.
2 shows an example in which they are arranged at positions of about ¼ and ¾ of the central angle of.

[0048]

EXAMPLES Next, specific examples of the high frequency measurement substrate of the present invention will be described.

Example 1 First, as a comparative example, in order to obtain a high-frequency measurement substrate according to the prior art, a conventional high-frequency measurement substrate shown in a plan view in FIG. 7 was produced. In FIG.
Reference numeral 61 is a dielectric substrate having a ground conductor deposited on substantially the entire lower surface, 62 is a signal conductor of a microstrip line formed on the upper surface of the dielectric substrate 61, and 63 is a signal conductor of a coplanar line portion, 64 is a signal conductor of a microstrip line
It is an equivalent grounding conductor formed by a semicircular or fan-shaped radial stub-shaped conductor pattern provided near the tip of 64.

As shown in FIG. 7, the relative permittivity is 9.6 and the thickness is 20.
A metal film made of Cr / Cu / Ni / Au was adhered and formed on almost the entire back surface of a dielectric substrate 61 made of 0 μm alumina ceramics. In addition, a signal conductor 62 of a microstrip line is formed on the upper surface of the dielectric substrate 61 with a conductor width of 190 μm.
And the coplanar line portion 63 at the tip of the conductor width.
The distance between the signal conductor and the ground metal was set to 135 μm and electrically connected to the tip of the signal conductor 62 of the microstrip line. Furthermore, the signal conductor 63 of the coplanar line portion (the tip of the signal conductor 62 of the microstrip line)
With the inner diameter 21
By forming a fan-shaped radial stub with an outer diameter of 580 μm and a central angle of 230 ° as the equivalent ground conductor 64,
A sample A of a conventional substrate for high frequency measurement was prepared.

Next, as in the case of the sample A, other than the above, as shown in FIG. 1, a portion of the equivalent ground conductor 34 having a fan-shaped radial stub shape is provided with a portion of about 1/4 and about 3 of the center angle.
At the circumferential position of / 4, notch-shaped conductor non-forming regions 35 and 35 ′ having a width of 5 ° at an angle of 5 ° are formed by leaving a conductor portion of 20 μm at the outermost peripheral portion. A sample B of a high frequency measurement substrate was prepared.

Then, with respect to these sample A and sample B, the characteristics corresponding to the frequency from the end of the microstrip line not connected to the coplanar line to the end of the coplanar line not connected to the microstrip line are extracted by electromagnetic field simulation. Then, from the extracted characteristics, a transmission coefficient (S ₂₁ ) was obtained as a transmission characteristic with respect to frequency as an evaluation index of the transmitted amount of the input signal.

Of these results, S ₂₁ of sample A is shown diagrammatically in FIG. In FIG. 8, the horizontal axis represents frequency (unit:
GHz), the vertical axis represents the amount of transmission (unit: dB), and the characteristic curve represents the frequency characteristic of the transmission coefficient S ₂₁ .

Further, as a comparison of the transmission characteristics of the sample A and the sample B, FIG. 4 shows the frequency characteristics of the transmission coefficient S ₂₁ of the two in a diagram. Also in FIG. 4, the horizontal axis represents frequency (unit: GHz),
The vertical axis represents the transmission amount (unit: dB), and S of sample B
_{21 is shown} by a solid line characteristic curve, and S ₂₁ of the sample A is shown by a broken line characteristic curve.

As can be seen from the above, the sample B, which is the high-frequency measurement substrate of the present invention, is provided with a predetermined conductor non-formation region in a part of the fan-shaped radial stub-shaped equivalent ground conductor, and thus the conventional high-frequency measurement is performed. As compared with the case where the conductor non-formed region is not provided as in the case of the sample substrate A, the resonance frequency is moved to the low frequency side, so that the low frequency side of the low loss frequency band is widened and a good wide band is obtained. It has low loss transmission characteristics. In particular, according to the shape of the sample B, since the path in which the charge density distribution is generated is the longest, the shape in which the charge distribution is greatly changed, and therefore the resonance frequency can be extremely effectively moved to the low frequency side. It was

Thus, according to the high frequency measuring substrate of the present invention, the resonance frequency is shifted to the low frequency side by providing a predetermined conductor non-forming region in a part of the radial stub-shaped equivalent ground conductor. It was confirmed that the substrate for high frequency measurement has excellent wide band low loss transmission characteristics.

Example 2 In the same manner as the sample A of [Example 1],
As shown in FIG. 2, a part of an equivalent ground conductor 44 having a fan-shaped radial stub shape is formed in a part of a center angle of about 1/4 and about 3/4.
Notch-shaped conductor non-forming regions 45 and 45 ′ along the radial direction having a width of 5 ° at the circumferential position of the innermost peripheral portion 20
Sample C of the substrate for high frequency measurement of the present invention was prepared by leaving the conductor portion of μm.

Then, the characteristics of these sample A and sample C were extracted in the same manner as in [Example 1], and from the extracted characteristics,
A transmission coefficient (S ₂₁ ) was obtained as a transmission characteristic with respect to frequency as an evaluation index of the transmitted amount of the input signal.

Regarding these results, FIG. 5 shows a comparison of the characteristics of Sample A and Sample C by a diagram. Also in FIG. 5, the horizontal axis represents frequency (unit: GHz) and the vertical axis represents transmission amount (unit: dB).
S ₂₁ of Sample C is shown by a solid line characteristic curve, and S ₂₁ of Sample A is shown by a broken line characteristic curve.

As can be seen from the above, the sample C, which is the high-frequency measurement substrate of the present invention, is provided with a predetermined conductor non-forming region in a part of the fan-shaped radial stub-shaped equivalent ground conductor, and thus the conventional high-frequency measurement is performed. As compared with the case where the conductor non-formed region is not provided as in the case of the sample substrate A, the resonance frequency is moved to the low frequency side, so that the low frequency side of the low loss frequency band is widened and a good wide band is obtained. It has low loss transmission characteristics. According to sample C, sample B
Compared with the above, it was confirmed that resonance occurs on the high frequency side due to the difference in the length of the path in which the charge density distribution occurs, and that the amount of movement of the resonance frequency can be set to a desired value depending on the shape of the conductor non-forming area. .

Thus, according to the high frequency measuring substrate of the present invention, the resonance frequency is moved to the low frequency side by providing a predetermined conductor non-forming region in a part of the radial stub-shaped equivalent ground conductor. It was confirmed that the substrate for high frequency measurement has excellent wide band low loss transmission characteristics.

Example 3 In the same manner as the sample A of [Example 1],
As shown in FIG. 3, a portion of the equivalent radial conductor 54 having a fan-shaped radial stub shape is provided with a portion of approximately 1/4 and approximately 3/4 of the central angle.
20 μm at the innermost peripheral portion of the rectangular conductor non-forming regions 55 and 55 ′ along the radial direction having a width of 5 ° at the circumferential position of
The conductor portion and the outermost peripheral portion having a thickness of 20 μm were left and formed to prepare a sample D of the high frequency measurement substrate of the present invention.

Then, the characteristics of these sample A and sample D were extracted in the same manner as in [Example 1], and from the extracted characteristics,
A transmission coefficient (S ₂₁ ) was obtained as a transmission characteristic with respect to frequency as an evaluation index of the transmitted amount of the input signal.

Regarding these results, FIG. 6 shows a comparison of the characteristics of the sample A and the sample D by a diagram. Also in FIG. 6, the horizontal axis represents frequency (unit: GHz), and the vertical axis represents transmission amount (unit: dB).
S ₂₁ of Sample D is shown by a solid characteristic curve, and S ₂₁ of Sample A is shown by a broken characteristic curve.

As can be seen from the above, the sample D, which is the high-frequency measurement substrate of the present invention, is provided with a predetermined conductor non-forming region in a part of the fan-shaped radial stub-shaped equivalent ground conductor, and thus the conventional high-frequency measurement is performed. As compared with the case where the conductor non-formed region is not provided as in the case of the sample substrate A, the resonance frequency is moved to the low frequency side, so that the low frequency side of the low loss frequency band is widened and a good wide band is obtained. It has low loss transmission characteristics. According to sample D, sample B
In comparison with Sample C, the resonance frequency is slightly higher than those due to the difference in the length of the path in which the charge density distribution occurs, and the amount of movement of the resonance frequency can be set to a desired value depending on the shape of the conductor non-forming region. I was able to confirm what I could do.

Thus, according to the high frequency measuring substrate of the present invention, the resonance frequency is moved to the low frequency side by providing a predetermined conductor non-forming region in a part of the radial stub-shaped equivalent ground conductor. It was confirmed that the substrate for high frequency measurement has excellent wide band low loss transmission characteristics.

The above is merely an example of the embodiment of the present invention, and the present invention is not limited thereto. Various modifications and improvements may be made without departing from the gist of the present invention. No problem.

[0068]

As described above, according to the high frequency measurement substrate of the first aspect of the present invention, the high frequency measurement substrate for contacting and electrically connecting the wafer probe of the coplanar line structure and the microstrip line. As an equivalent ground conductor is formed in the shape of a semi-circular or fan-shaped radial stub near the tip of the microstrip line on the upper surface of the dielectric substrate, and a conductor is not formed along the radial direction in a part of the equivalent ground conductor. Since the conductor non-forming area which is a portion is provided, the circumferential length of the semicircular or fan-shaped substantially central position in the radial direction becomes an effective length of one wavelength like a conventional radial stub-shaped equivalent ground conductor. When the corresponding frequency is located in the low-loss transmission frequency band, the charge distribution in the circumferential direction becomes a standing distribution in which the density becomes higher at the circumferential end and middle parts of the semicircular or fan-shaped resonance. Since the effect of the equivalent ground hardly occurs because it occurs, the characteristic impedance becomes discontinuous, and as a result, the reflection of the incident signal increases and the transmission amount of the high frequency signal does not decrease. . The resonance frequency moves to the low frequency side as compared to the case where the conductor non-formed region is not provided, and the low frequency side of the low loss frequency band is widened. As a result, it was possible to obtain a high-frequency measurement substrate having good wideband low-loss transmission characteristics.

According to a second aspect of the present invention, there is provided a high frequency measuring substrate according to the first aspect, wherein the conductor-free region has a radial length of a semicircular or fan-shaped radial stub. Since the radial width of the equivalent ground conductor is equal to or more than half, the circumferential length of the semicircular or fan-shaped radial center is approximately the same as the conventional radial stub equivalent ground conductor. When the frequency corresponding to the effective length of one wavelength is located in the low-loss transmission frequency band, the circumferential charge distribution has a semi-circular or fan-shaped standing distribution in which the density becomes high at the circumferential end and in the middle. As a result, the effect of the equivalent ground hardly occurs because resonance occurs, and as a result, the characteristic impedance becomes discontinuous, and as a result, the reflection with respect to the incident signal increases and the transmission amount of the high frequency signal decreases. It is possible to effectively eliminate that. In addition, the resonance frequency moves to the low frequency side as compared with the case where the conductor non-formation region is not provided, so that the low frequency side of the low loss frequency band can be effectively widened, so that the low loss transmission characteristic As a result, the frequency band is widened, and as a result, it is possible to obtain a high frequency measurement substrate having a good wide band low loss transmission characteristic.

According to a third aspect of the present invention, there is provided a high frequency measuring substrate according to the first or second aspect, in which a radial stub-shaped equivalent ground conductor in the conductor non-forming region is formed. The position in the circumferential direction is about a quarter or about a third of the central angle of the semicircle or fan shape,
Alternatively, since they are arranged at the positions of about 1/4 and 3/4, the circumference of the semicircular or fan-shaped substantially center position in the radial direction is the same as the conventional equivalent radial stub ground conductor. When the frequency whose length in the direction corresponds to the effective length of one wavelength is located within the low-loss transmission frequency band, the charge distribution in the circumferential direction becomes higher in the semicircular or fan-shaped circumferential end and middle portions. The effect of an equivalent ground is almost nonexistent due to a standing distribution and resonance, which results in discontinuity of the characteristic impedance, resulting in increased reflection of incident signals and transmission of high-frequency signals. Can be efficiently eliminated.
In addition, the resonance frequency moves to the low frequency side as compared with the case where the conductor non-forming region is not provided, and thus the low frequency side of the low loss frequency band can be efficiently expanded. As a result, the frequency band was widened, and as a result, it was possible to obtain a high-frequency measurement substrate having excellent wide-band low-loss transmission characteristics.

According to a fourth aspect of the high frequency measurement board of the present invention, in the high frequency measurement board according to any one of the first to third aspects, one end of the conductor non-formation area is a radial stub-shaped equivalent ground. Since it is provided in a notch shape open to the inner or outer circumference of the conductor, the circumferential length of the semicircular or fan-shaped radial center is approximately the same as the conventional radial stub-shaped equivalent ground conductor. When the frequency corresponding to the effective length of one wavelength is located in the low-loss transmission frequency band, the circumferential charge distribution has a semi-circular or fan-shaped standing distribution in which the density becomes high at the circumferential end and in the middle. As a result, the effect of an equivalent ground hardly occurs because resonance occurs, and as a result, the characteristic impedance becomes discontinuous, and as a result, the reflection with respect to the incident signal increases and the transmission amount of the high frequency signal decreases. Can be eliminated more efficiently that Utoyuu. In addition, the resonance frequency moves to the low frequency side as compared with the case where the conductor non-formation region is not provided, so that the low frequency side of the low loss frequency band can be more efficiently widened, so that the low loss transmission characteristic As a result, the frequency band is widened, and as a result, it is possible to obtain a high frequency measurement substrate having a good wide band low loss transmission characteristic.

Further, according to the high frequency measuring substrate of the present invention, there is no need for a highly accurate substrate processing step as in the case of the conventional high frequency measuring substrate using through conductors such as through holes and via holes. Therefore, it becomes possible to easily and inexpensively provide a high-frequency measurement substrate capable of highly accurate measurement.

As described above, according to the present invention, in the high frequency measurement board using the radial stub as an equivalent ground, the resonance frequency of the radial stub is moved to the low frequency side to widen the low loss transmission frequency band. It was possible to provide the high frequency measurement substrate.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of an embodiment of a high frequency measurement substrate of the present invention.

FIG. 2 is a plan view showing another example of the embodiment of the high frequency measurement substrate of the present invention.

FIG. 3 is a plan view showing still another example of the embodiment of the high frequency measurement substrate of the present invention.

FIG. 4 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 5 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 6 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 7 is a plan view showing an example of a conventional high-frequency measurement substrate as a comparative example.

FIG. 8 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 9 is a plan view showing an example of a conventional high-frequency measurement substrate.

FIG. 10 is a diagram showing a reflection characteristic with respect to frequency in a high frequency measurement substrate.

FIG. 11 is a diagram showing transmission characteristics with respect to frequency in a high frequency measurement substrate.

FIG. 12 is a plan view showing an example of a conventional high-frequency measurement substrate.

FIG. 13 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 14 is a plan view showing an example of a conventional high frequency measurement substrate.

FIG. 15 is a plan view showing an example of a radial stub.

[Explanation of symbols]

31, 41, 51 ... Dielectric substrates 32, 42, 52 ... Signal conductors 34, 44, 54 ... ..... Equivalent ground conductors 35, 35 ', 45, 45', 55, 55 '... Conductor non-formation area

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI H01P 1/00 G01R 31/28 K 5/08 H01L 27/04 T (58) Fields investigated (Int.Cl. ⁷ , DB name) ) G01R 31/28 G01R 1/06 G01R 31/26 H01L 27/04 H01P 1/00 H01P 5/08

Claims (4)

(57) [Claims] 1. A ground conductor is formed on substantially the entire lower surface of a dielectric substrate, and a signal conductor of a microstrip line and an equivalent ground of a semicircular or fan-shaped radial stub provided near the tip of the signal conductor on the upper surface. And a conductor is formed,
A high frequency measurement board for electrically connecting a signal conductor and a ground conductor of a wafer probe having a coplanar line structure to the signal conductor and the equivalent ground conductor, respectively, in a radial direction in a part of the equivalent ground conductor. A substrate for high frequency measurement, characterized in that a conductor non-forming region is provided along the substrate. 2. The substrate for high frequency measurement according to claim 1, wherein the radial length of the conductor non-forming region is equal to or more than half the radial width of the equivalent ground conductor. 3. The conductor non-formation region is arranged at a position of approximately ¼ and / or approximately 3/4 of a central angle of the equivalent ground conductor. Two
The substrate for high frequency measurement described. 4. The substrate for high frequency measurement according to claim 1, wherein one end in a radial direction of the conductor non-forming region is opened to an inner circumference or an outer circumference of the equivalent ground conductor.