Microstrip line, exposure mask, and method for evaluating microstrip line

Abstract

To provide a microstrip line capable of efficiently measuring dielectric and conductive characteristics of a high frequency circuit with high accuracy even when a high frequency signal such as a millimeter wave band is input, a method for evaluating the same, and an exposure mask used for manufacturing the microstrip line.SOLUTION: A microstrip line according to the present invention includes a dielectric layer having a first surface and a second surface that are opposite to each other, a ground conductor provided on the first surface, a first strip conductor and a second strip conductor provided on the second surface and extending linearly, and a pad portion provided on the second surface so as to be adjacent to the first strip conductor and the second strip conductor, respectively, and electrically connected to the ground conductor, and widths of the first strip conductor and the second strip conductor are different from each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a microstrip line, an exposure mask, and a method for evaluating the microstrip line. [Background technology]

[0002] In recent years, efforts to utilize millimeter-wave electromagnetic waves, which have higher frequencies than microwaves, have been progressing. Electronic devices that use millimeter-wave electromagnetic waves use high-frequency circuits compatible with the millimeter-wave band. Reducing transmission loss in the high-frequency range is an issue for such high-frequency circuits.

[0003] In light of this, development of low-loss materials compatible with high frequencies such as the millimeter wave band is underway. High-frequency circuits are primarily composed of dielectric substrates and conductor lines, and both of these components affect transmission loss in the high-frequency range. Therefore, in order to understand in detail the causes of transmission loss, a technique is needed to measure the conductor loss and dielectric loss of high-frequency circuits separately in the high-frequency range.

[0004] Conventionally, methods for measuring the high-frequency characteristics of dielectrics and conductors as individual bodies have been known. However, transmission loss is affected by the structure of the high-frequency circuit, such as the structure of the dielectric substrate and the surface roughness of the conductor line. This makes it difficult to accurately calculate the dielectric loss and conductor loss in the high-frequency circuit state from the high-frequency characteristics of the dielectric and conductor as individual bodies.

[0005] Therefore, Patent Document 1 discloses a method for separately determining the dielectric loss and the conductor loss in a high-frequency circuit state from the transmission loss of a microstrip line.

[0006] Specifically, Patent Document 1 discloses a method for calculating dielectric characteristics, which includes a step of measuring the total loss of each of the first and second microstrip lines, a step of calculating the conductor loss of the strip conductor of each microstrip line, and a step of obtaining the dielectric loss from the calculation result. The first and second microstrip lines are made of the same dielectric material, but the plate thicknesses of the insulating substrates made of the dielectric material are different from each other. By utilizing this relationship, the conductor loss of each strip conductor can be calculated.

[0007] In addition, the dielectric loss can be calculated using the relational equation that holds between the total loss obtained from the first microstrip line and the conductor loss of the strip conductor, and the relational equation that holds between the total loss obtained from the second microstrip line and the conductor loss of the strip conductor.

[0008] According to the above calculation method, both the conductor loss and the dielectric loss of the microstrip line can be calculated. If the transmission loss can be separated into each factor in this way, the cause of the transmission loss in the high frequency circuit can be easily understood, which contributes to the development of new high frequency circuits. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2001-255346 A Summary of the Invention [Problem to be solved by the invention]

[0010] In the invention described in Patent Document 1, it is necessary to prepare a plurality of insulating substrates with different thicknesses. Insulating substrates with different thicknesses often have different internal structures. For this reason, an evaluation method using insulating substrates with different thicknesses has a problem that it takes time to prepare samples and the measurement accuracy of dielectric loss and conductor loss decreases due to the influence of the internal structures of insulating substrates with different thicknesses.

[0011] Conventional evaluation methods include the triplate line resonator method and the dielectric resonator method, which are capable of evaluating high-frequency circuits in the microwave band but have difficulty evaluating high-frequency circuits in the millimeter wave band.

[0012] An object of the present invention is to provide a microstrip line that allows the dielectric and conductive characteristics of a high-frequency circuit to be measured efficiently and with high accuracy even when a high-frequency signal such as a millimeter wave band is input, a method for evaluating the same, and an exposure mask used to manufacture the microstrip line. [Means for solving the problem]

[0013] Such an object can be achieved by the present invention described below in (1) to (17). (1) a dielectric layer having a first surface and a second surface which are reverse to each other; a ground conductor provided on the first surface; a first strip conductor and a second strip conductor provided on the second surface and extending linearly; a pad portion provided on the second surface adjacent to the first strip conductor and the second strip conductor, the pad portion being electrically connected to the ground conductor; Equipped with The microstrip line, wherein the first strip conductor and the second strip conductor have different widths.

[0014] (2) The microstrip line according to (1) above, wherein the first strip conductor and the second strip conductor have the same length.

[0015] (3) When a direction from a center toward one end in a longitudinal direction of the first strip conductor is defined as a first A direction, and a direction from the center toward the other end is defined as a first B direction, the pad section has a first A pad adjacent to the one end of the first strip conductor and a first B pad adjacent to the other end of the first strip conductor, the 1A pad extends from a position in the 1B direction beyond the one end of the first strip conductor to a position in the 1A direction beyond the one end, The microstrip line according to (1) or (2) above, wherein the 1B pad extends from a position in the 1A direction further than the other end of the first strip conductor to a position in the 1B direction further than the other end.

[0016] (4) The microstrip line according to (3) above, wherein the pad section has a plurality of the first A pads and a plurality of the first B pads.

[0017] (5) When a direction from a center toward one end in a longitudinal direction of the second strip conductor is defined as a second A direction, and a direction from the center toward the other end is defined as a second B direction, the pad section has a second A pad adjacent to the one end of the second strip conductor and a second B pad adjacent to the other end of the second strip conductor, the 2A pad extends from a position in the 2B direction beyond the one end of the second strip conductor to a position in the 2A direction beyond the one end, The microstrip line according to (3) or (4) above, wherein the 2B pad extends from a position in the 2A direction further than the other end of the second strip conductor to a position in the 2B direction further than the other end.

[0018] (6) The microstrip line according to (5) above, wherein the pad section has a plurality of the second A pads and a plurality of the second B pads.

[0019] (7) The microstrip line according to any one of (1) to (6) above, wherein the thickness of the pad portion is greater than the thickness of the first strip conductor and the thickness of the second strip conductor.

[0020] (8) The microstrip line according to any one of (1) to (7) above, wherein the first strip conductor and the second strip conductor extend parallel to each other.

[0021] (9) The microstrip line according to any one of (1) to (8) above, further comprising a third strip conductor having the same width as the first strip conductor but a different length.

[0022] (10) The microstrip line according to any one of (1) to (9) above, further comprising a fourth strip conductor having the same width as the second strip conductor but a different length.

[0023] (11) A microstrip line according to any one of (1) to (10) above, to which a high-frequency signal is input and which is used for evaluating high-frequency characteristics.

[0024] (12) An exposure mask having a shielding portion and a transmitting portion and used in an exposure process for a metal foil-clad laminate, comprising: a shape of the shielding portion or a shape of the transmitting portion corresponds to a line pattern formed on the metal foil-clad laminate, The line pattern is a first strip conductor and a second strip conductor that are different in width and extend linearly; a pad portion provided adjacent to the first strip conductor and the second strip conductor, An exposure mask comprising:

[0025] (13) preparing a microstrip line including a dielectric layer having a first surface and a second surface, the first surface being a reverse surface of the dielectric layer, a ground conductor provided on the first surface, and a first strip conductor and a second strip conductor provided on the second surface, the first strip conductor and the second strip conductor having different widths and extending linearly; measuring transmission characteristics of the first strip conductor and the second strip conductor to obtain a resonant frequency and an unloaded Q value; calculating an effective dielectric constant and an effective conductivity of the microstrip line based on the resonant frequency and the unloaded Q value; A method for evaluating a microstrip line, comprising:

[0026] (14) The method for evaluating a microstrip line according to (13) above, further comprising the step of calculating conductor losses corresponding to the first strip conductor and the second strip conductor based on the effective conductivity.

[0027] (15) The method for evaluating a microstrip line according to (14) above, further comprising the step of calculating dielectric losses corresponding to the first strip conductor and the second strip conductor based on the conductor losses.

[0028] (16) The method for evaluating a microstrip line according to (15) above, further comprising the step of calculating a relative dielectric constant and a dielectric loss tangent of the dielectric layer based on the resonant frequency, the unloaded Q value, and the dielectric loss.

[0029] (17) The microstrip line includes a pad portion provided on the second surface adjacent to the first strip conductor and electrically connected to the ground conductor, The step of acquiring the resonant frequency and the unloaded Q value includes: An operation of bringing a high-frequency probe having a signal terminal and a ground terminal close to the microstrip line; an operation of contacting the ground terminal with the pad portion and disposing the signal terminal at a position away from the first strip conductor; A method for evaluating a microstrip line according to any one of (13) to (16) above, comprising: Effect of the Invention

[0030] According to the present invention, a microstrip line is obtained that can measure the dielectric and conductive characteristics of a high-frequency circuit efficiently and with high accuracy, even when transmitting a high-frequency signal such as a millimeter wave band signal.

[0031] Furthermore, according to the present invention, it is possible to provide a method for evaluating a microstrip line, which is capable of determining the dielectric and conductive characteristics of a high-frequency circuit with high accuracy.

[0032] Furthermore, according to the present invention, there is obtained an exposure mask capable of manufacturing a microstrip line that allows the dielectric and conductive characteristics of a high-frequency circuit to be measured efficiently with high accuracy when the microstrip line is manufactured through an exposure process. [Brief description of the drawings]

[0033] [Figure 1] FIG. 2 is a plan view showing a microstrip line according to the embodiment. [Diagram 2] 2 is a cross-sectional view taken along line X1-X1 of FIG. 1. [Diagram 3] FIG. 2 is a perspective view for explaining a method for evaluating the microstrip line shown in FIG. [Figure 4] 1 is a flowchart for explaining a method for evaluating a microstrip line according to an embodiment. [Diagram 5] 4 is an example of a waveform showing the transmission characteristics of a microstrip line. [Figure 6] FIG. 13 is a diagram showing an example of waveforms superimposed on each other, showing the transmission characteristics measured for five strip conductors each having a different width w. [Figure 7] 1 is a graph created by plotting the unloaded Q values ​​Q0 obtained from five strip conductors each having a different width w in a Cartesian coordinate system. [Figure 8]1 is a flowchart for explaining an example of a manufacturing method of a microstrip line. [Figure 9] FIG. 9 is a schematic diagram for explaining the exposure step shown in FIG. 8. [Figure 10] 10 is a plan view showing an example of an exposure mask used in the exposure step shown in FIG. [Figure 11] FIG. 11 is a plan view showing a microstrip line according to a first modified example. [Figure 12] This figure compares example waveforms showing the transmission characteristics when the order of the resonance point at which the resonance frequency fr and the unloaded Q value Q0 are obtained is the same for the strip conductors (a) and different for the strip conductors (b). [Figure 13] FIG. 11 is a plan view showing a microstrip line according to a second modified example. [Figure 14] FIG. 11 is a perspective view for explaining a method for evaluating a microstrip line according to a second modified example. [Figure 15] FIG. 13 is a plan view showing a microstrip line according to a third modified example. [Figure 16] FIG. 11 is a cross-sectional view showing a microstrip line according to a fourth modified example. [Figure 17] FIG. 13 is a plan view showing a microstrip line according to a fifth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A microstrip line, an exposure mask, and a method for evaluating a microstrip line according to the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

[0035] 1. Microstrip lines First, a microstrip line according to an embodiment will be described.

[0036] Fig. 1 is a plan view showing a microstrip line 1 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view taken along the line X1-X1 in Fig. 1. Fig. 3 is a perspective view for explaining a method for evaluating the microstrip line shown in Fig. 1.

[0037] In each drawing of the present application, three mutually orthogonal axes are set as an X-axis, a Y-axis, and a Z-axis, which are indicated by arrows. The base end of the arrow is called the "negative side" of each axis, and the tip end of the arrow is called the "positive side" of each axis. In the present specification, a view from a viewpoint on the Z-axis is called a "planar view."

[0038] The microstrip line 1 shown in Fig. 1 and Fig. 2 includes a dielectric layer 2 and a conductor portion 3. The microstrip line 1 according to this embodiment functions as a resonator such as a half-wave resonator. Such a microstrip line 1 is connected to a measuring device such as a network analyzer 9 using, for example, high-frequency probes 81 and 82 shown in Fig. 3 or a coaxial connector (not shown), and the transmission characteristic S 21 By measuring the dielectric properties of the dielectric layer 2 and the conductive properties of the conductor portion 3 in the high frequency range, the measurement is used to evaluate the high frequency properties.

[0039] The dielectric layer 2 is made of a dielectric material and corresponds to, for example, an insulating substrate of a printed wiring board. The dielectric layer 2 has a first surface 201 and a second surface 202 which are opposite surfaces as shown in FIG.

[0040] Examples of the dielectric material include resin materials such as fluororesin, liquid crystal polymer, and polyimide; ceramic materials such as alumina and silica; glass materials such as borosilicate glass; and composite materials such as glass epoxy materials and glass ceramic materials.

[0041] 2, the thickness of the dielectric layer 2 is denoted by h. The thickness h of the dielectric layer 2 is not particularly limited, but is preferably, for example, 0.001 mm or more and 2.0 mm or less, and more preferably 0.05 mm or more and 0.30 mm or less.

[0042] The conductor portion 3 is composed of a conductor and corresponds to, for example, the wiring of a printed wiring board. As shown in FIGS. 1 and 2, the conductor portion 3 includes a ground conductor 30, a first strip conductor 311 and a second strip conductor 312, a pad portion 33, and a via wiring 34.

[0043] The ground conductor 30 is a conductor provided on the first surface 201 of the dielectric layer 2. The ground conductor 30 may be provided in a range that at least covers the first strip conductor 311 and the second strip conductor 312 when the second surface 202 is seen through from the first surface 201 side.

[0044] The first strip conductor 311 and the second strip conductor 312 are conductors provided on the second surface 202 of the dielectric layer 2. The first strip conductor 311 and the second strip conductor 312 each have a linear shape extending in the Y-axis direction. In this specification, the length along the Y-axis of the first strip conductor 311 and the second strip conductor 312 is referred to as "length", the length along the X-axis is referred to as "width", and the length along the Z-axis is referred to as "thickness". Also, the first strip conductor 311 and the second strip conductor 312 are arranged side by side along the X-axis.

[0045] In FIG. 1, let the width of the first strip conductor 311 be w1 and the width of the second strip conductor 312 be w2. In the present embodiment, the widths w1 and w2 satisfy the relationship w1 < w2. By providing the microstrip line 1 with the first strip conductor 311 and the second strip conductor 312 having different widths, the effective dielectric constant of the dielectric layer 2 and the effective conductivity of the conductor portion 3 can be easily obtained in the evaluation method described later. Note that the widths w1 and w2 are not particularly limited, but are preferably 20 to 5000 μm, and more preferably 50 to 300 μm.

[0046] In Fig. 1, the length of the first strip conductor 311 is L1, and the length of the second strip conductor 312 is L2. In this embodiment, the length L1 and the length L2 satisfy the relationship L1 = L2. The lengths L1 and L2 are appropriately set according to the frequency at which the high-frequency characteristics are measured. The lengths L1 and L2 are not particularly limited, but are preferably 0.05 to 100 mm, and more preferably 0.5 to 40 mm.

[0047] The pad portion 33 is a conductor provided on the second surface 202 of the dielectric layer 2. The pad portion 33 is electrically connected to the ground conductor 30 through a via wiring .

[0048] As shown in FIG. 1, the pad section 33 has two first A pads 335A, 335A and two first B pads 335B, 335B.

[0049] The two 1A pads 335A, 335A are provided adjacent to one end 331 of the first strip conductor 311. Specifically, the 1A pads 335A are provided adjacent to one end 331 of the first strip conductor 311 on the positive side and the negative side of the X-axis, respectively.

[0050] In this embodiment, the positions of the ends on the positive side of the Y axis are shifted between one end 331 of the first strip conductor 311 and the two 1A pads 335A, 335A. Specifically, as shown in Fig. 1, the end of the 1A direction of the 1A pad 335A is positioned further in the 1A direction than the one end 331 of the first strip conductor 311. The 1A direction is the direction from the center in the longitudinal direction of the first strip conductor 311 toward the one end 331. In Fig. 1, the 1A direction is denoted as "1A".

[0051] The two 1B pads 335B, 335B are provided adjacent to each other at the other end 332 of the first strip conductor 311. Specifically, the 1B pads 335B are provided adjacent to each other on the positive side and the negative side of the X-axis of the other end 332 of the first strip conductor 311, respectively.

[0052] In this embodiment, the positions of the ends on the negative Y-axis side are shifted between the other end 332 of the first strip conductor 311 and the two 1B pads 335B, 335B. Specifically, as shown in Fig. 1, the end in the 1B direction of the 1B pad 335B is positioned further in the 1B direction than the other end 332 of the first strip conductor 311. The 1B direction is the direction from the center in the longitudinal direction of the first strip conductor 311 toward the other end 332. In Fig. 1, the 1B direction is denoted as "1B".

[0053] As shown in FIG. 1, the pad section 33 has two second A pads 336A, 336A and two second B pads 336B, 336B.

[0054] The two second A pads 336A, 336A are provided adjacent to one end 333 of the second strip conductor 312. Specifically, the second A pads 336A are provided adjacent to one end 333 of the second strip conductor 312 on the positive side and the negative side of the X-axis, respectively.

[0055] In this embodiment, the positions of the ends on the positive side of the Y axis are shifted between one end 333 of the second strip conductor 312 and the two 2A pads 336A, 336A. Specifically, as shown in Fig. 1, the end of the 2A direction of the 2A pad 336A is located further in the 2A direction than the one end 333 of the second strip conductor 312. The 2A direction is the direction from the center in the longitudinal direction of the second strip conductor 312 toward the one end 333. In Fig. 1, the 2A direction is denoted as "2A".

[0056] The two 2B pads 336B, 336B are provided adjacent to the other end 334 of the second strip conductor 312. Specifically, the 2B pads 336B are provided adjacent to the other end 334 of the second strip conductor 312 on the positive side and the negative side of the X-axis, respectively.

[0057] In this embodiment, the positions of the ends on the negative Y-axis side are shifted between the other end 334 of the second strip conductor 312 and the two 2B pads 336B, 336B. Specifically, as shown in FIG. 1, the end in the 2B direction of the 2B pad 336B is located further in the 2B direction than the other end 334 of the second strip conductor 312. The 2B direction is the direction from the center in the longitudinal direction of the second strip conductor 312 toward the other end 334. In FIG. 1, the 2B direction is denoted as "2B".

[0058] The lengths of the offsets G1A, G1B, G2A, and G2B are not particularly limited, but are preferably 30 μm to 3 mm, and more preferably 100 μm to 1 mm, which makes it easy to align the high-frequency probes 81 and 82 without deteriorating the measurement accuracy of the high-frequency characteristics.

[0059] The via wiring 34 is a wiring that penetrates the dielectric layer 2 so as to electrically connect the 1A pad 335A, the 1B pad 335B, the 2A pad 336A, and the 2B pad 336B to the ground conductor 30, respectively.

[0060] Examples of the conductor constituting the conductor portion 3 include simple substances such as Cu, Al, Ni, Ag, and Au, and alloys containing at least one of these. The conductor portion 3 may be a single layer or a multilayer in which layers with different compositions are laminated.

[0061] The shape of the pad section 33 in plan view is not limited to the shape shown in the figure. For example, the pad section 33 may have a portion other than the 1A pad 335A, the 1B pad 335B, the 2A pad 336A, and the 2B pad 336B. Examples of such a portion include a frame surrounding a structural unit composed of the 1st strip conductor 311, the 1A pad 335A, and the 1B pad 335B, a frame surrounding a structural unit composed of the 2nd strip conductor 312, the 2A pad 336A, and the 2B pad 336B, and a frame surrounding a plurality of structural units collectively.

[0062] 2. Evaluation method for microstrip lines Next, a method for evaluating a microstrip line will be described. In the following description, the microstrip line 1 shown in Figures 1 and 2 will be described as an evaluation target. In the following description, the first strip conductor 311 and the second strip conductor 312 of the microstrip line 1 may be simply referred to as the "strip conductors."

[0063] FIG. 4 is a flowchart for explaining the method for evaluating a microstrip line according to the embodiment.

[0064] The method for evaluating a microstrip line shown in FIG. 4 includes a preparation step S102, a measurement step S104, a first calculation step S106, a second calculation step S108, a third calculation step S110, and a fourth calculation step S112.

[0065] 2.1. Preparation process In the preparation step S102, the above-mentioned microstrip line 1 is prepared. In addition, a network analyzer 9 that inputs a high-frequency signal to the microstrip line 1, and high-frequency probes 81 and 82 that electrically connect the network analyzer 9 and the microstrip line 1 are prepared.

[0066] For example, a vector network analyzer is used as the network analyzer 9. The frequency of the high-frequency signal input / output to / from the network analyzer 9 is not particularly limited, but is preferably 0.1 to 1000 GHz, more preferably 1 to 300 GHz, and even more preferably 10 to 300 GHz.

[0067] The high-frequency probe 81 is a GSG probe including two ground probes 81G and one signal probe 81S. The high-frequency probe 82 is a GSG probe including two ground probes 82G and one signal probe 82S.

[0068] The length L1 of the first strip conductor 311 and the length L2 of the second strip conductor 312 of the microstrip line 1 are each calculated according to the frequency of the high-frequency characteristic to be measured by the following formula (1).

[0069]

number

[0070] In the above formula (1), L is the length L1 [m] of the first strip conductor 311 and the length L2 [m] of the second strip conductor 312. ε eff is the effective dielectric constant of the microstrip line 1. m is a positive integer, preferably an integer between 1 and 15. c is the speed of light (3×10 8 f r is the resonant frequency [Hz].

[0071] The resonant frequency f is set to a value close to the frequency of the high frequency characteristic to be measured. r By selecting these lengths, the lengths L1 and L2 suitable for measuring the high frequency characteristics can be obtained based on the above formula (1). In addition, the effective dielectric constant ε eff is calculated by the following formula (2).

[0072]

number

[0073] ε in the above formula (2) r is the relative dielectric constant of the dielectric layer 2. h is the thickness [m] of the dielectric layer 2. w is the width w1 [m] of the first strip conductor 311 and the width w2 [m] of the second strip conductor 312. B is the ratio of the thickness h, the width w, and the relative dielectric constant ε r is not particularly limited, but can be set to, for example, about 0.5 to 0.6.

[0074] Moreover, it is preferable that the width w1 [m] and the width w2 [m] are appropriately set according to the thickness h [m] of the dielectric layer 2 and the characteristic impedance Z0 of the microstrip line 1, respectively.

[0075] The characteristic impedance Z0 of the microstrip line 1 is calculated by the following formula (3).

[0076]

number

[0077] The characteristic impedance Z0 of the microstrip line 1 obtained by the above formula (3) is preferably within a range of, for example, 30 to 300 Ω, taking into consideration the characteristics of the network analyzer 9 and the high-frequency probes 81 and 82. A is a constant determined by the thickness h and width w, and is not particularly limited, but can be, for example, about 6.0. These values ​​and the general relative dielectric constant ε of the dielectric layer 2 are r In view of this, it is preferable to set w / h to about 0.001 to 8.0, thereby determining the widths w1 and w2 suitable for measuring high frequency characteristics.

[0078] Although the method for setting the lengths L1, L2 and the widths w1, w2 has been described above, the method for setting these is not limited to the above method.

[0079] 2.2.Measurement process In the measurement step S104, the transmission characteristics of the microstrip line 1 are measured. Specifically, high-frequency probes 81 and 82 are brought into contact with the microstrip line 1. Then, a high-frequency signal is supplied from the network analyzer 9 to the microstrip line 1 via the high-frequency probe 81 to cause resonance. Next, the transmission characteristics S 21 Then, from the transmission characteristics, the resonance frequency f r and obtain the no-load Q value Q0.

[0080] In the measurement step S104, first, the transmission characteristics of the first strip conductor 311 are measured.

[0081] Specifically, the two ground probes 81G, 81G of the high frequency probe 81 are brought into contact with the two 1A pads 335A, 335A, and the signal probe 81S of the high frequency probe 81 is disposed at a position away from the first strip conductor 311. Similarly, the two ground probes 82G, 82G of the high frequency probe 82 are brought into contact with the two 1B pads 335B, 335B, and the signal probe 82S of the high frequency probe 82 is disposed at a position away from the first strip conductor 311.

[0082] When the high-frequency signal that has passed through the microstrip line 1 is detected by the network analyzer 9, a waveform exhibiting transmission characteristics such as that shown in Fig. 5 is obtained. From the viewpoint of improving the reproducibility of the contact state between the microstrip line 1 and the high-frequency probes 81 and 82 described above, it is preferable that the first strip conductor 311, the second strip conductor 312 and the pad portion 33 have the same thickness.

[0083] Fig. 5 is an example of a waveform showing the transmission characteristics of the microstrip line 1. Two peaks P1 and P2 are observed in the waveform shown in Fig. 5. Peak P1 is a resonance point corresponding to the fundamental resonance (first-order resonance mode). Peak P2 is a resonance point corresponding to a higher-order resonance (second-order resonance mode).

[0084] Next, set either the frequency of peak P1 or P2 as the resonant frequency f r Here, as an example, the frequency of the peak P1 is obtained as the resonant frequency f r Obtain as.

[0085] Next, the unloaded Q value Q0 is obtained from the waveform of the peak P1. To obtain the unloaded Q value Q0, for example, a half-width method is used.

[0086] As a result of the above, the transmission characteristics of the first strip conductor 311 are measured, and the resonant frequency f rand the no-load Q value Q0 can be obtained.

[0087] In the measuring step S104, the transmission characteristics of the second strip conductor 312 are then measured.

[0088] The transmission characteristics of the second strip conductor 312 are measured in the same manner as the transmission characteristics of the first strip conductor 311 .

[0089] In this manner, the transmission characteristics of the second strip conductor 312 are measured, and the resonant frequency f r and the no-load Q value Q0 can be obtained.

[0090] In the above description, the first strip conductor 311 and the second strip conductor 312 are each assumed to have a resonant frequency f r and the unloaded Q value Q0 is obtained, but for three or more strip conductors with different widths w, the resonant frequency f r and the no-load Q value Q0 are preferably obtained. This makes it possible to improve the calculation accuracy of the effective conductivity and the like obtained in the calculation step described below.

[0091] As an example, Fig. 6 shows an example of waveforms showing transmission characteristics measured for five strip conductors with different widths w. In this example, the transmission characteristics have a resonant frequency f r By changing the width w of the strip conductor from 80 μm to 240 μm, it can be seen that the position of the peak corresponding to the resonance point shifts in the waveform shown in Figure 6, and the sharpness of the peak changes. In other words, the resonance frequency f r and the unloaded Q value Q0 changes. Therefore, it is preferable that the microstrip line 1 has three or more strip conductors with different widths w, and more preferably five or more.

[0092] 2.3.First calculation step In the first calculation step S106, first, the resonance frequency f obtained in the measurement step S104 is calculated. r Using this, the phase constant β is calculated according to the following formula (5).

[0093]

number

[0094] In the above formula (5), m is a positive integer, and the obtained resonant frequency f r For example, in the case of the first resonance (fundamental resonance) mode, the order m is 1, and in the case of the second resonance mode, the order m is 2.

[0095] From the above equation (5), the phase constant β and effective dielectric constant ε of the microstrip line 1 are eff The effective dielectric constant ε eff is a value calculated based on the electric field generated in the thickness direction of the dielectric layer 2. Therefore, the effective dielectric constant ε calculated based on the above formula (5) eff Even if the dielectric layer 2 has anisotropy in its internal structure in the planar direction and thickness direction, this anisotropy is well reflected.

[0096] In the first calculation step S106, the calculated effective dielectric constant ε eff Using this, the characteristic impedance Z0 of each strip conductor is calculated using the following formula (3).

[0097]

number

[0098] In this way, the phase constant β and the effective dielectric constant ε eff , and characteristic impedance Z0.

[0099] Here, the no-load Q value Q0 and the conductor Q value Q c and the dielectric quality factor Q d , phase constant β, conductor loss α c and dielectric loss αd The following equation (6) holds between

[0100]

number

[0101] On the other hand, the conductor quality factor Q c and conductor loss α c The following equation (7) holds between

[0102]

number

[0103] In addition, the conductor loss α c and the width w of the strip conductor, the following equation (8) holds:

[0104]

number

[0105] Then, from the above formula (7) and formula (8), the conductor Q value Q c It can be derived that the reciprocal of is proportional to the reciprocal of the width w of the strip conductor. The microstrip line 1 has multiple strip conductors with different widths w. Therefore, by using multiple strip conductors with different widths w that the microstrip line 1 has, the conductor Q value Q c The reciprocal rate of change can be calculated.

[0106] In addition, σ in the above formula (8) eff is the effective conductivity of the microstrip line 1. K c is the proportionality coefficient.

[0107] Here, it has been found that the above-mentioned ratio is almost equal to the ratio of the change in the reciprocal of the no-load Q value Q0 to the change in the reciprocal of the strip conductor width w. In other words, the change in the reciprocal of the no-load Q value Q0 to the change in the reciprocal of the strip conductor width w is mainly due to the conductor Q value Q c It is known that the change in the reciprocal of the no-load Q value Q0 is caused by the following. Therefore, by utilizing this relationship, in the first calculation step S106, the ratio of the change in the reciprocal of the strip conductor width w is calculated from the no-load Q values ​​Q0 obtained from multiple widths w and multiple strip conductors. Then, using this, K in the above formula (8) is calculated. c / √σ eff Derive:

[0108] This can be derived, for example, by plotting the reciprocal of the width w of the strip conductor and the reciprocal of the no-load Q factor Q0 on each axis of a Cartesian coordinate system using a graph.

[0109] FIG. 7 is a graph created by plotting the unloaded Q value Q0 obtained from five strip conductors with different widths w in an orthogonal coordinate system. The horizontal axis of the graph in FIG. 7 is the reciprocal 1 / w of the width w of the strip conductor, and the vertical axis is the reciprocal 1 / Q0 of the unloaded Q value Q0. FIG. 7 also shows a regression line obtained from the five plot marks as a solid line. Furthermore, FIG. 7 also shows data obtained when the conductivity of the conductor portion 3 is set to three levels, large, medium, and small, by changing the manufacturing conditions, that is, data obtained from multiple microstrip lines with different manufacturing conditions.

[0110] As shown in Fig. 7, there is a positive correlation between the reciprocal 1 / w of the width w of the strip conductor and the reciprocal 1 / Q0 of the unloaded Q value Q0, which increases at a constant gradient a, regardless of the conductivity of the conductor portion 3. Therefore, from the gradient a of the regression line in the graph shown in Fig. 7, K in the above formula (8) for each microstrip line can be calculated using the following formula (9): c / √σ eff can be derived.

[0111]

number

[0112] By the way, the conductor loss α c is theoretically defined by the following equation (10).

[0113]

number

[0114] g in the above formula (10) c (w, t, h) are the geometric factors of the microstrip line 1, and are not particularly limited, but are values ​​that are not significantly dependent on the width w of the strip conductor, and therefore are within the range of, for example, 0.6 to 0.7. ω is the resonant frequency f r is the angular frequency, ω=2πf r μ0 is the magnetic permeability of a vacuum.

[0115] Then, the following formula (11) is derived from the above formula (8) and formula (10).

[0116]

number

[0117] Since the characteristic impedance Z0 has been calculated, the proportionality coefficient K c Then, the effective conductivity σ of the microstrip line 1 is calculated by the above formula (9). eff is required.

[0118] 2.4.Second calculation process In the second calculation step S108, the proportionality coefficient K calculated in the first calculation step S106 is c and the effective conductivity σ of the microstrip line 1 eff is substituted into the above formula (8) or (10). This results in the conductor loss α c is required.

[0119] 2.5.Third calculation process In the third calculation step S110, first, the following formula (12) is derived from the above formula (6).

[0120]

number

[0121] Next, the phase constant β calculated in the first calculation step S106 and the conductor loss α of each strip conductor calculated in the second calculation step S108 are c is substituted into the above equation (12). This gives the conductor Q value Q of the microstrip line 1. c is required.

[0122] Next, the unloaded Q value Q0 obtained in the measurement step S104 and the conductor Q value Q c is substituted into the above formula (6). This gives the dielectric Q value Q of the microstrip line 1. d is required.

[0123] In the third calculation step S110, next, the following formula (13) is derived from the above formula (6).

[0124]

number

[0125] Next, the phase constant β calculated in the first calculation step S106 and the dielectric Q value Q calculated in this step d is substituted into the above equation (13). This gives the dielectric loss α d is required.

[0126] 2.6.Fourth calculation process The effective dielectric constant ε calculated in the first calculation step S106 described above eff is expressed by the following formula (2).

[0127]

number

[0128] In the above formula (2), the relative dielectric constant ε r The parameters other than the above are already known. Then, from the above formula (2), the relative dielectric constant ε r is required.

[0129] On the other hand, the dielectric loss α calculated in the third calculation step S110 described above d is theoretically defined by the following equation (14).

[0130]

number

[0131] Therefore, the dielectric loss α calculated in the third calculation step S110 d , the effective dielectric constant ε calculated in the first calculation step S106 eff , and the relative dielectric constant ε of the dielectric layer 2 obtained in this step r is substituted into the above formula (14). This gives the dielectric tangent tan δ of the dielectric layer 2. Note that λ0 in the above formula (14) is the wavelength in free space of the high-frequency signal input to the microstrip line 1.

[0132] As described above, the evaluation method of the microstrip line according to this embodiment includes a preparation step S102, a measurement step S104, and a first calculation step S106. In the preparation step S102, for example, a microstrip line 1 is prepared. The microstrip line 1 includes a dielectric layer 2 having a first surface 201 and a second surface 202 that are reverse to each other, a ground conductor 30 provided on the first surface 201, and a first strip conductor 311 and a second strip conductor 312 that are provided on the second surface 202, have different widths, and extend linearly. In the measurement step S104, the transmission characteristics of the first strip conductor 311 and the second strip conductor 312 are measured, and a resonant frequency f r and the unloaded Q value Q0 are obtained. In the first calculation step S106, the resonant frequency f r Based on the unloaded quality factor Q0, the effective dielectric constant ε eff and effective conductivity σeff Calculate.

[0133] With this configuration, even when a high-frequency signal such as a millimeter-wave signal is input, it is possible to efficiently measure both the dielectric and conductive characteristics of the microstrip line 1 without the trouble of preparing multiple insulating substrates with different thicknesses as in the conventional method. eff In addition, the dielectric loss α corresponding to the strip conductor is derived from the above. d , the relative dielectric constant ε of the dielectric layer 2 r and dielectric tangent tanδ. The conductive characteristics refer to the effective conductivity σ eff In addition, the conductor loss α corresponding to the strip conductor is derived from the above. c This makes it easy to understand, for example, whether the main cause of transmission loss in a high-frequency circuit is on the dielectric layer 2 side or on the conductor portion 3 side. As a result, new high-frequency circuits can be developed efficiently.

[0134] Furthermore, in the above method, the dielectric and conductive properties are measured by applying an electric field in the thickness direction of the dielectric layer 2. Therefore, even if the internal structure of the dielectric layer 2 is anisotropic, the dielectric and conductive properties reflecting this anisotropy can be measured with high accuracy. As a result, high-frequency circuits equipped with a dielectric layer 2 having an anisotropic internal structure can be efficiently developed.

[0135] The method for evaluating a microstrip line according to the present embodiment also includes a second calculation step S108. As described above, the second calculation step S108 calculates the effective conductivity σ eff Based on this, the conductor loss α corresponding to the first strip conductor 311 and the second strip conductor 312, i.e., each strip conductor, is calculated. c Calculate.

[0136] By having such a second calculation step S108, the conductor loss α cThis makes it possible to obtain basic data for a more precise understanding of the causes of transmission loss in high-frequency circuits.

[0137] Furthermore, the evaluation method of the microstrip line according to the present embodiment includes a third calculation step S110. In the third calculation step S110, as described above, the conductor loss α c Based on this, the first strip conductor 311 and the second strip conductor 312, i.e., the dielectric loss α corresponding to each strip conductor, d Calculate.

[0138] By including such a third calculation step S110, the dielectric loss α d This makes it possible to obtain basic data for a more precise understanding of the causes of transmission loss in high-frequency circuits.

[0139] The method for evaluating a microstrip line according to the present embodiment also includes a fourth calculation step S112. In the fourth calculation step S112, as described above, the resonant frequency f r , unloaded Q value Q0 and dielectric loss α d Based on this, the relative dielectric constant ε r and the dielectric tangent tan δ is calculated.

[0140] By including such a fourth calculation step S112, it is possible to obtain the physical property values ​​of the dielectric layer 2 alone in the high frequency range, and therefore it is possible to obtain basic data necessary for the development of dielectric materials.

[0141] Although the method for evaluating a microstrip line according to the present embodiment has been described above, the order of the steps is not limited to the above order and may be changed. In addition, at least one of the second calculation step S108, the third calculation step S110, and the fourth calculation step S112 may be omitted. Furthermore, the effective dielectric constant ε eff , effective conductivity σ eff , conductor loss α c , dielectric loss α d, relative permittivity ε r The method of calculating the dielectric tangent tan δ is not limited to the above method, and another calculation method may be adopted.

[0142] The microstrip line 1 according to this embodiment includes a dielectric layer 2, a ground conductor 30, a first strip conductor 311, a second strip conductor 312, and a pad portion 33. The dielectric layer 2 has a first surface 201 and a second surface 202, which are opposite surfaces. The ground conductor 30 is provided on the first surface 201. The first strip conductor 311 and the second strip conductor 312 are provided on the second surface 202 and extend linearly. The pad portion 33 is provided on the second surface 202 adjacent to the first strip conductor 311 and the second strip conductor 312, respectively, and is conductive with the ground conductor 30. The first strip conductor 311 and the second strip conductor 312 have widths w that are different from each other.

[0143] With this configuration, even when a high-frequency signal such as a millimeter wave band is input, a microstrip line 1 can be obtained that can efficiently measure both the dielectric characteristics and conductive characteristics of a high-frequency circuit without the need to take the time and effort required in the past to prepare multiple insulating substrates with different thicknesses.

[0144] Furthermore, in the microstrip line 1, an electric field is applied in the thickness direction of the dielectric layer 2. Therefore, even if the internal structure of the dielectric layer 2 is anisotropic, the dielectric and conductive characteristics that reflect this anisotropy can be measured with high accuracy.

[0145] In the microstrip line 1 according to this embodiment, the first strip conductor 311 and the second strip conductor 312 have the same length.

[0146] According to this configuration, when the order of the resonance point at which the unloaded Q value Q0 is obtained is the same, the resonance frequency f r and the resonant frequency f obtained for the second strip conductor 312. rBy doing so, the unloaded Q value Q0 can be obtained from the resonance point of the same order, and the dielectric and conductive characteristics of the microstrip line 1 at the frequency to be measured can be measured with higher accuracy.

[0147] The first strip conductor 311 and the second strip conductor 312 may have different lengths. In this case, it is possible to calculate the dielectric characteristics and the conductive characteristics by performing a correction during calculation.

[0148] In this embodiment, the 1A pad 335A extends from a position in the 1B direction further than one end 331 of the first strip conductor 311 to a position in the 1A direction further than the one end 331. In this embodiment, the 1B pad 335B extends from a position in the 1A direction further than the other end 332 of the first strip conductor 311 to a position in the 1B direction further than the other end 332. As a result, a "deviation G1A" occurs in the Y-axis direction between the one end 331 and the end of the 1A pad 335A. In addition, a "deviation G1B" occurs in the Y-axis direction between the other end 332 and the 1B pad 335B.

[0149] According to this configuration, since there are offsets G1A and G1B, it becomes easier to maintain a non-contact state between the high-frequency probes 81, 82 and the first strip conductor 311, as shown in Fig. 3. In other words, with the ground probes 81G, 82G in contact with the pad portion 33, it becomes easier to arrange the signal probes 81S, 82S at a position away from the first strip conductor 311. This makes it easier to measure the resonance characteristics of the first strip conductor 311. In other words, since the signal probes 81S, 82S and the first strip conductor 311 are loosely electrically coupled, the transmission characteristic S 21reflects almost only the characteristics of the first strip conductor 311. This state reduces the influence of impedance mismatch in the circuit including the network analyzer 9 and the high-frequency probes 81 and 82 shown in FIG. 3 and the contact resistance between the high-frequency probes 81 and 82 and the first strip conductor 311. Therefore, by keeping the high-frequency probes 81 and 82 out of contact with the first strip conductor 311, it is possible to suppress a decrease in measurement accuracy. This makes it possible to improve the measurement accuracy of the high-frequency characteristics. Also, it is possible to avoid damage to the first strip conductor 311 due to contact between the high-frequency probes 81 and 82.

[0150] In this embodiment, the pad section 33 has a plurality of 1A pads 335A and a plurality of 1B pads 335B. This provides the microstrip line 1 whose high-frequency characteristics can be measured using the high-frequency probes 81 and 82, which are GSG probes. As a result, the high-frequency characteristics can be measured with higher accuracy.

[0151] In this embodiment, the 2A pad 336A extends from a position in the 2B direction further than one end 333 of the second strip conductor 312 to a position in the 2A direction further than the one end 333. In this embodiment, the 2B pad 336B extends from a position in the 2A direction further than the other end 334 of the second strip conductor 312 to a position in the 2B direction further than the other end 334. As a result, a "deviation G2A" occurs between the one end 333 and the end of the 2A pad 336A in the Y-axis direction. In addition, a "deviation G2B" occurs between the other end 334 and the 2B pad 336B in the Y-axis direction.

[0152] According to this configuration, since the offsets G2A and G2B exist, it is easy to keep the high-frequency probes 81 and 82 out of contact with the second strip conductor 312. In other words, it is easy to arrange the signal probes 81S and 82S at a position away from the second strip conductor 312 while the ground probes 81G and 82G are in contact with the pad portion 33. This makes it easy to measure the resonance characteristics of the second strip conductor 312, and the contact state between the high-frequency probes 81 and 82 and the second strip conductor 312 is less likely to affect the measurement results of the high-frequency characteristics. This makes it possible to improve the measurement accuracy of the high-frequency characteristics. In addition, it is also possible to avoid damage to the second strip conductor 312 due to the contact of the high-frequency probes 81 and 82.

[0153] In this embodiment, the pad section 33 has a plurality of 2A pads 336A and a plurality of 2B pads 336B. This provides the microstrip line 1 whose high-frequency characteristics can be measured using the high-frequency probes 81 and 82, which are GSG probes. As a result, the high-frequency characteristics can be measured with higher accuracy.

[0154] Furthermore, the first strip conductor 311 and the second strip conductor 312 may be non-parallel to each other, but in this embodiment they extend parallel to each other.

[0155] The internal structure of the dielectric layer 2 generally has uniformity along one direction. Therefore, by arranging the first strip conductor 311 and the second strip conductor 312 in parallel with each other, the internal structure of the dielectric layer 2 is less likely to adversely affect the measurement accuracy of the dielectric characteristics and conductive characteristics. As a result, the evaluation accuracy of the microstrip line 1 can be further improved.

[0156] The microstrip line 1 can be used for various purposes, but is preferably used to input a high-frequency signal and evaluate high-frequency characteristics. The high-frequency characteristics refer to the dielectric characteristics and conductive characteristics described above. By using it for such purposes, the feature of the microstrip line 1, that is, that it has multiple strip conductors with different widths w, can be more effectively utilized.

[0157] 1 includes the pad portion 33 that is electrically connected to the ground conductor 30, as described above. In the method for evaluating a microstrip line according to this embodiment, the above-mentioned resonant frequency f r The measurement process S104 for acquiring the unloaded Q value Q0 includes an operation of bringing high-frequency probes 81, 82, which have signal probes 81S, 82S as signal terminals and ground probes 81G, 82G as ground terminals, close to the microstrip line 1, and an operation of bringing the ground probes 81G, 82G into contact with the pad portion 33 and positioning the signal probes 81S, 82S at a position away from the first strip conductor 311.

[0158] By including such an operation, as described above, in the measurement step S104, the high-frequency probes 81, 82 and the first strip conductor 311 can be kept in a non-contact state. This makes it difficult for problems such as impedance mismatch and contact resistance to become apparent. As a result, the measurement accuracy of the high-frequency characteristics can be improved.

[0159] 3. Manufacturing method of microstrip line Next, an example of a method for manufacturing a microstrip line will be described.

[0160] The microstrip line can be manufactured using a known method for manufacturing a printed wiring board.

[0161] Fig. 8 is a flow chart for explaining an example of a method for manufacturing a microstrip line. Fig. 9 is a schematic diagram for explaining the exposure step shown in Fig. 8. Fig. 10 is a plan view showing an example of an exposure mask 6 used in the exposure step shown in Fig. 9.

[0162] The manufacturing method of the microstrip line shown in FIG. 8 includes a preparation step S202, a resist application step S204, an exposure step S206, a development step S208, an etching step S210, and a resist removal step S212.

[0163] In the preparation step S202, as shown in Fig. 9, a metal foil-clad laminate 100 is prepared in which metal foil 300 is formed on both sides of a dielectric layer 200. The metal foil 300 may be a single layer, or may be a multilayer in which layers of different compositions are laminated. In the case of a multilayer, some of the layers may be layers formed by a film formation method such as plating.

[0164] In the resist coating step S204, a photoresist is coated on one of the metal foils 300. This forms a photoresist film 700. The photoresist film 700 may be either positive type or negative type.

[0165] 9, in the exposure step S206, an exposure process is performed in which the photoresist film 700 is irradiated with light LT through an exposure mask 6. As a result, if the photoresist film 700 is a positive type, the solubility in the developer of the portion irradiated with light LT increases. Also, if the photoresist film 700 is a negative type, the solubility in the developer of the portion irradiated with light LT decreases.

[0166] The exposure mask 6 used in the exposure process S206 is designed and manufactured according to the shapes of the strip conductor and pad parts to be manufactured. The exposure mask 6 shown in Fig. 10 has a mask pattern used in manufacturing the microstrip line 1 shown in Fig. 1.

[0167] Specifically, the exposure mask 6 shown in FIG. 10 has a shielding portion 61 and a transmitting portion 62, and is a mask used in the exposure process of the metal foil-clad laminate 100. The shielding portion 61 shields the light LT, and the transmitting portion 62 transmits the light LT. When the photoresist film 700 is a positive type, as shown in FIG. 10, the shape of the shielding portion 61 corresponds to the conductor pattern formed on the metal foil-clad laminate 100, that is, the first strip conductor 311, the second strip conductor 312, and the pad portion 33 shown in FIG. 1. When the photoresist film 700 is a negative type, the shape of the transmitting portion corresponds to an area other than the conductor pattern, although not shown. In this specification, it is said that the shape of the shielding portion 61 or the shape of the transmitting portion 62 corresponds to the line pattern formed on the metal foil-clad laminate 100, referring to both of these.

[0168] 1 extend linearly and have different widths, as described above. Also, the pad portion 33 is provided adjacent to the first strip conductor 311 and the second strip conductor 312, as described above.

[0169] With this configuration, it is possible to obtain an exposure mask 6 capable of manufacturing a microstrip line 1 suitable for use in evaluating high-frequency circuits as described above. In other words, by using the exposure mask 6, it is possible to collectively form, on one dielectric layer 2, a line pattern including a first strip conductor 311 and a second strip conductor 312 having different widths.

[0170] In the development step S208, the metal foil-clad laminate 100 that has been subjected to the exposure process is brought into contact with a developer. This causes the relatively more soluble areas to dissolve in the developer. As a result, the portions of the photoresist film 700 that correspond to the above-mentioned line pattern remain, and the other portions are removed. This causes the photoresist film 700 to be patterned.

[0171] In the etching step S210, an etching process is performed on the metal foil-clad laminate 100. As a result, the metal foil 300 is patterned into the shape of a line pattern according to the pattern of the photoresist film 700.

[0172] In the resist removal step S212, the photoresist film 700 is removed. This results in the conductor portion 3 shown in Fig. 1. After that, a cleaning process is performed to obtain the microstrip line 1 shown in Fig. 1.

[0173] 4. First Modification Next, a microstrip line according to a first modified example will be described. FIG. 11 is a plan view showing a microstrip line 1a according to a first modified example.

[0174] The first modified example will be described below, focusing on the differences from the above embodiment and omitting the description of the similarities. Note that in each drawing, the same reference numerals are used to designate the same components as those in the above embodiment.

[0175] The first modified example is similar to the above embodiment, except that in addition to a plurality of strip conductors with different widths w, a plurality of strip conductors with different lengths L are provided.

[0176] The conductor portion 3 of the microstrip line 1a shown in FIG. 11 includes a first strip conductor 311 and a second strip conductor 312, as well as a third strip conductor 313 and a fourth strip conductor 314.

[0177] The third strip conductor 313 is disposed on the negative side of the first strip conductor 311 along the Y axis. The fourth strip conductor 314 is disposed on the negative side of the second strip conductor 312 along the Y axis.

[0178] The third strip conductor 313 and the fourth strip conductor 314 are conductors provided on the second surface 202 of the dielectric layer 2. The third strip conductor 313 and the fourth strip conductor 314 are each linear and extend in the Y-axis direction. Also, the third strip conductor 313 and the fourth strip conductor 314 are arranged along the X-axis.

[0179] In FIG. 11, let the width of the third strip conductor 313 be w3 and the width of the fourth strip conductor 314 be w4. In the first modification, the widths w3 and w4 satisfy the relationship w3 < w4. Also, in the first modification, the widths w1, w2, w3, and w4 satisfy the relationships w1 = w3 and w2 = w4.

[0180] In FIG. 11, let the length of the third strip conductor 313 be L3 and the length of the fourth strip conductor 314 be L4. In the first modification, the lengths L3 and L4 satisfy the relationship L3 = L4. The lengths L3 and L4 are appropriately set according to the frequency at which the high-frequency characteristics are measured. Also, in the first modification, the lengths L1, L2, L3, and L4 satisfy the relationships L1 < L3 and L2 < L4.

[0181] By providing the microstrip line 1a with strip conductors having different widths w from each other and different lengths L from each other, it becomes possible to select the strip conductor to be used for measurement according to the frequency of the high-frequency characteristics to be measured. Thereby, the high-frequency characteristics can be measured at various frequencies. For example, in the above-described embodiment, the high-frequency characteristics are measured using the first strip conductor 311 and the second strip conductor 312, but in the first modification, not only that, but the high-frequency characteristics can also be measured using the third strip conductor 313 and the fourth strip conductor 314. Therefore, in the first modification, the high-frequency characteristics can be measured for four frequencies (at least two frequencies).

[0182] Also, the resonance frequency f rThe orders of the resonance points at which the unloaded Q value Q0 is obtained may be the same or different between the strip conductors.

[0183] Figure 12 shows the resonant frequency f r This figure compares example waveforms showing the transmission characteristics when the order of the resonance point at which the unloaded Q value Q0 is obtained is the same for all strip conductors (a) and different for all strip conductors (b).

[0184] In Fig. 12(a), the waveforms of the resonance points corresponding to the fundamental resonance are shown superimposed for a pair of strip conductors S1 and S2, which have different widths w and the same length L. Specifically, the strip conductor S1 has a length L of 40 mm and a width w of 160 µm. The strip conductor S2 has a length L of 40 mm and a width w of 100 µm. The fundamental resonance resonant frequency f r Therefore, in the transmission characteristics shown in FIG. 12(a), the resonance frequency f r and no-load Q value Q0.

[0185] 12(b), the waveforms of the resonance points corresponding to the fundamental resonance and the waveforms of the resonance points corresponding to the higher-order resonance are shown superimposed for a pair of strip conductors S3 and S4 and a pair of strip conductors S5 and S6, which have the same width w but different lengths L. Specifically, the strip conductor S3 has a length L of 20 mm and a width w of 160 μm. The strip conductor S4 has a length L of 40 mm and a width w of 160 μm. The strip conductor S5 has a length L of 20 mm and a width w of 100 μm. The strip conductor S6 has a length L of 40 mm and a width w of 100 μm.

[0186] The fundamental resonance frequency f of the transmission characteristics of the strip conductors S3 and S5 r The resonant frequency f of the second resonance of the transmission characteristics of the strip conductors S4 and S6 is about 4.5 GHz. r12(b) is obtained, the above-mentioned parameters may be obtained, for example, from the resonance point corresponding to the fundamental resonance of the strip conductor S3 and the resonance point corresponding to the secondary resonance of the strip conductor S6. Similarly, the above-mentioned parameters may be obtained from the resonance point corresponding to the secondary resonance of the strip conductor S4 and the resonance point corresponding to the fundamental resonance of the strip conductor S5.

[0187] Considering the above example, in the above-mentioned measurement step S104, the parameters acquired from the resonance point corresponding to the fundamental resonance and the parameters acquired from the resonance point corresponding to the higher-order resonance may be used together. Also, the parameters acquired from the resonance points corresponding to the higher-order resonances having mutually different orders m may be used together. By using the microstrip line 1a shown in FIG. 11, the parameters can be easily acquired from such resonance points having mutually different orders m.

[0188] Whether these parameters can be obtained from resonance points of different orders m can be determined by comparing the unloaded Q values ​​Q0. For example, if the unloaded Q value Q0 obtained for the strip conductor S3 is compared with the unloaded Q value Q0 obtained for the strip conductor S4 and the unloaded Q value Q0 obtained for the strip conductor S4 are highly consistent, the above parameters can be used together. In FIG. 12(b), the waveforms showing the transmission characteristics of the strip conductors S3 and S4 are almost overlapped near the resonance points, so the unloaded Q values ​​Q0 obtained from the resonance points are also highly consistent. The same is true for the strip conductors S5 and S6.

[0189] As described above, the microstrip line 1a according to the first modified example further includes the third strip conductor 313 having the same width w as the first strip conductor 311 and a different length L.

[0190] According to such a configuration, it is possible to obtain a microstrip line 1a that allows measurement of high-frequency characteristics at various frequencies, that is, acquisition of parameters from resonance points of different orders m.

[0191] Moreover, the microstrip line 1a according to the first modification further includes a fourth strip conductor 314 having the same width w as the second strip conductor 312 and a length L different from that of the second strip conductor 312.

[0192] According to such a configuration, it is possible to obtain a microstrip line 1a that allows measurement of high-frequency characteristics at various frequencies, that is, acquisition of parameters from resonance points of different orders m.

[0193] The number of strip conductors included in the microstrip line 1a is not particularly limited, but is preferably 10 or more, and more preferably 20 or more. The upper limit of the number of strip conductors is not particularly limited, but is preferably 1000 or less, and more preferably 500 or less, in order to prevent the microstrip line 1a from becoming excessively large.

[0194] Moreover, the number of widths w is preferably 3 or more, more preferably 5 or more, and even more preferably 10 or more. Moreover, the number of lengths L is preferably 3 or more, more preferably 5 or more, and even more preferably 10 or more. In the first modified example as described above, the same effects as those of the above embodiment can be obtained.

[0195] 5. Second Modification Next, a microstrip line according to a second modified example will be described.

[0196] Fig. 13 is a plan view showing a microstrip line 1b according to the second modified example, and Fig. 14 is a perspective view for explaining a method for evaluating the microstrip line according to the second modified example.

[0197] The second modified example will be described below, focusing on the differences from the above embodiment and omitting the description of the similarities. Note that in each drawing, the same reference numerals are used to designate the same components as those in the above embodiment.

[0198] The second modified example is similar to the above embodiment, except that the arrangement of the pad portions with respect to the strip conductor is different.

[0199] A microstrip line 1b shown in FIG. 13 includes a first strip conductor 311, a second strip conductor 312, and a pad portion 33, similar to FIG.

[0200] In the embodiment, the positions of the ends on the positive side of the Y axis of one end 331 of the first strip conductor 311 and the two first A pads 335A are misaligned.

[0201] In contrast, in the second modified example, as shown in FIG. 13, the end of the 1A pad 335A in the 1A direction is aligned with one end 331 of the first strip conductor 311 in the Y-axis direction.

[0202] In the embodiment, the positions of the ends on the negative Y-axis side of the other end 332 of the first strip conductor 311 and the two 1B pads 335B are misaligned.

[0203] In contrast, in the second modified example, as shown in FIG. 13, the end of the 1B pad 335B in the 1B direction is aligned with the other end 332 of the first strip conductor 311 in the Y-axis direction.

[0204] 14, the two ground probes 81G, 81G of the high-frequency probe 81 can be brought into contact with the two 1A pads 335A, 335A, and the signal probe 81S of the high-frequency probe 81 can be brought into contact with the first strip conductor 311. Similarly, the two ground probes 82G, 82G of the high-frequency probe 82 can be brought into contact with the two 1B pads 335B, 335B, and the signal probe 82S of the high-frequency probe 82 can be brought into contact with the first strip conductor 311. As a result, the transmission characteristic S can be measured by the network analyzer 9 via the high-frequency probe 82. 21 can be measured.

[0205] At this time, instead of the measurement step S104, the transmission characteristic S 21 The transmission loss α is calculated from the absolute value of the transmission characteristic S 21 A step of obtaining a phase constant β from the phase of the phase can be performed. In addition, the unloaded Q value Q0 of the transmission is defined by the following equation (16).

[0206]

number

[0207] By applying these to the first calculation step S106, it is possible to obtain the effective dielectric constant and the effective conductivity at any frequency not limited to the resonant frequency. As described above, in the second modified example, the same effects as those in the above embodiment can be obtained.

[0208] 6.Third Modification Next, a microstrip line according to a third modified example will be described. FIG. 15 is a plan view showing a microstrip line 1c according to a third modified example.

[0209] The third modified example will be described below, but in the following description, the differences from the second modified example will be mainly described, and the description of the similar points will be omitted. Note that in each drawing, the same reference numerals are used to designate the same configurations as the second modified example.

[0210] The third modification example is the same as the second modification example, except that in addition to a plurality of strip conductors having different widths w, it includes a plurality of strip conductors having different lengths L.

[0211] The conductor part 3 included in the microstrip line 1c shown in FIG. 15 includes a third strip conductor 313 and a fourth strip conductor 314 in addition to the first strip conductor 311 and the second strip conductor 312.

[0212] The third strip conductor 313 is disposed on the minus Y-axis side of the first strip conductor 311. The fourth strip conductor 314 is disposed on the minus Y-axis side of the second strip conductor 312.

[0213] The third strip conductor 313 and the fourth strip conductor 314 are conductors provided on the second surface 202 of the dielectric layer 2. The third strip conductor 313 and the fourth strip conductor 314 each have a linear shape extending in the Y-axis direction. Also, the third strip conductor 313 and the fourth strip conductor 314 are arranged along the X-axis.

[0214] In FIG. 15, let the width of the third strip conductor 313 be w3 and the width of the fourth strip conductor 314 be w4. In the third modification example, the width w3 and the width w4 satisfy the relationship w3 < w4. Also, in the third modification example, the widths w1, w2, w3, and w4 satisfy the relationships w1 = w3 and w2 = w4.

[0215] In FIG. 15, let the length of the third strip conductor 313 be L3 and the length of the fourth strip conductor 314 be L4. In the third modification example, the lengths L3 and L4 satisfy the relationship L3 = L4. The lengths L3 and L4 are appropriately set according to the frequency at which the high-frequency characteristics are measured. Also, in the third modification example, the lengths L1, L2, L3, and L4 satisfy the relationships L1 < L3 and L2 < L4.

[0216] By providing the microstrip line 1c with strip conductors having different widths w and different lengths L, it becomes possible to estimate the influence of contact between the strip conductors and the high-frequency probe. This makes it possible to measure high-frequency characteristics at various frequencies with high accuracy. For example, in the second modification, the high-frequency characteristics are measured using the first strip conductor 311 and the second strip conductor 312. In the third modification, the high-frequency characteristics can be measured using the third strip conductor 313 and the fourth strip conductor 314. Since the influence of the probe contact is the same for all strip conductors, the value obtained by subtracting the transmission characteristic of the first strip conductor 311 from the transmission characteristic of the third strip conductor 313 and the value obtained by subtracting the transmission characteristic of the second strip conductor 312 from the transmission characteristic of the fourth strip conductor 314 are the values ​​obtained by canceling the loss due to the contact between the high-frequency probe and the strip conductor. This makes it possible to perform a more reliable measurement by removing the influence of contact.

[0217] The number of strip conductors included in the microstrip line 1c is not particularly limited, but is preferably 10 or more, and more preferably 20 or more. The upper limit of the number of strip conductors is not particularly limited, but is preferably 1000 or less, and more preferably 500 or less, in order to prevent the microstrip line 1c from becoming significantly large.

[0218] As described above, the number of widths w is preferably 3 or more, more preferably 5 or more, and even more preferably 10 or more. Furthermore, the number of lengths L is preferably 3 or more, more preferably 5 or more, and even more preferably 10 or more.

[0219] The third modified example as described above also provides the same effects as the first and second modified examples.

[0220] 7. Fourth Modification Next, a microstrip line according to a fourth modified example will be described. FIG. 16 is a cross-sectional view showing a microstrip line 1d according to the fourth modification.

[0221] The fourth modification will be described below, focusing on the differences from the above embodiment and omitting the description of the similarities. Note that in each drawing, the same reference numerals are used to designate the same components as those in the above embodiment.

[0222] In the embodiment, the first strip conductor 311, the second strip conductor 312 and the pad portion 33 have the same thickness.

[0223] In contrast to this, in the fourth modified example, the thickness of the pad portion 33 is greater than the thickness of the first strip conductor 311 and the thickness of the second strip conductor 312. As a result, for example, when the two ground probes 81G, 81G of the high-frequency probe 81 are brought into contact with the two first A pads 335A, 335A, the signal probe 81S of the high-frequency probe 81 is held at a position away from the first strip conductor 311. As a result, similar to the above embodiment, it becomes easy to measure the resonance characteristics of the first strip conductor 311. In other words, since the signal probes 81S, 82S and the first strip conductor 311 are loosely electrically coupled, the transmission characteristics S 21 reflects almost only the characteristics of the first strip conductor 311. This improves the measurement accuracy of the high frequency characteristics. It also makes it possible to prevent damage to the first strip conductor 311 due to contact with the high frequency probe 81. The firstB pad 335B, the secondA pad 336A, and the secondB pad 336B are similar to the firstA pad 335A. In the fourth modified example as described above, the same effects as those of the above embodiment can be obtained.

[0224] 8. Fifth Modification Next, a microstrip line according to a fifth modified example will be described. FIG. 17 is a plan view showing a microstrip line 1e according to the fifth modified example.

[0225] The fifth modification will be described below, focusing on the differences from the above embodiment and omitting the description of the similarities. Note that in each drawing, the same reference numerals are used to designate the same components as those in the above embodiment.

[0226] In the embodiment, two 1A pads 335A, 335A and two 1B pads 335B, 335B are provided adjacent to each other on the first strip conductor 311. Also, two 2A pads 336A, 336A and two 2B pads 336B, 336B are provided adjacent to each other on the second strip conductor 312.

[0227] 17, in the fifth modified example, one 1A pad 335A and one 1B pad 335B are adjacent to the first strip conductor 311. Also, one 2A pad 336A and one 2B pad 336B are adjacent to the second strip conductor 312.

[0228] According to this configuration, even when the high-frequency probes 81 and 82 shown in Fig. 1 are GS probes instead of GSG probes, it is possible to provide a microstrip line 1e suitable for them. This makes it possible to reduce the cost of the high-frequency probes 81 and 82. In addition, since the area of ​​the pad portion 33 can be relatively small, it is possible to reduce the size of the microstrip line 1e.

[0229] Although the microstrip line, the exposure mask, and the method for evaluating the microstrip line of the present invention have been described above based on the illustrated embodiments, the present invention is not limited to these.

[0230] For example, the microstrip line and the exposure mask of the present invention may be obtained by replacing each part of the embodiment and the modified example with any component having the same function, or may be obtained by adding any component to the embodiment and the modified example. Furthermore, the microstrip line of the present invention may be obtained by combining at least two or more of the embodiment and the modified examples.

[0231] Furthermore, the microstrip line evaluation method of the present invention may include any step added for any purpose to the above-described embodiment. [Explanation of symbols]

[0232] 1. Microstrip line 1a Microstrip line 1b Microstrip line 1c Microstrip line 1d microstrip line 1e Microstrip Line 2. Dielectric Layer 3 Conductor 6 Exposure mask 9. Network Analyzer 30 Ground Conductor 33 Pad section 34 Via wiring 61 Shielding part 62 Transparent part 81 High Frequency Probe 81G Ground Probe 81S Signal Probe 82 High Frequency Probe 82G Ground Probe 82S Signal Probe 100 Metal foil laminate 200 Dielectric layer 201 Page 1 202 2nd page 300 Metal Foil 311 First strip conductor 312 Second Strip Conductor 313 Third Strip Conductor 314 4th Strip Conductor 331 one end 332 Other end 333 one end 334 Other end 335A 1A Pad 335B 1B Pad 336A 2nd A Pad 336B 2nd B Pad 700 Photoresist film G1A deviation G1B deviation G2A deviation G2B deviation h Thickness L1 Length L2 Length L3 Length L4 Length LT Hikari P1 peak P2 peak S1 Strip conductor S2 Strip conductor S3 Strip conductor S4 Strip conductor S5 Strip Conductor S6 Strip conductor S102 Preparation process S104 Measurement process S106 1st calculation process S108 2nd calculation process S110 3rd calculation process S112 4th calculation process S202 Preparation process S204 Resist coating process S206 Exposure process S208 Development process S210 Etching process S212 Resist removal process w1 width w2 Width w3 width w4 Width

Claims

1. a dielectric layer having a first surface and a second surface which are reverse to each other; a ground conductor provided on the first surface; a first strip conductor and a second strip conductor provided on the second surface and extending linearly; a pad portion provided on the second surface adjacent to the first strip conductor and the second strip conductor, the pad portion being electrically connected to the ground conductor; Equipped with The microstrip line, wherein the first strip conductor and the second strip conductor have different widths.

2. The microstrip line according to claim 1 , wherein the first strip conductor and the second strip conductor have the same length.

3. When a direction from the center toward one end in the longitudinal direction of the first strip conductor is defined as a first A direction, and a direction from the center toward the other end is defined as a first B direction, the pad section has a first A pad adjacent to the one end of the first strip conductor and a first B pad adjacent to the other end of the first strip conductor, the first A pad extends from a position in the first B direction beyond the one end of the first strip conductor to a position in the first A direction beyond the one end, 3. The microstrip line according to claim 1, wherein the first B pad extends from a position in the first A direction beyond the other end of the first strip conductor to a position in the first B direction beyond the other end.

4. The microstrip line according to claim 3 , wherein the pad section includes a plurality of the first A pads and a plurality of the first B pads.

5. When a direction from the center toward one end in the longitudinal direction of the second strip conductor is defined as a second A direction, and a direction from the center toward the other end is defined as a second B direction, the pad section has a second A pad adjacent to the one end of the second strip conductor and a second B pad adjacent to the other end of the second strip conductor, the second A pad extends from a position in the second B direction beyond the one end of the second strip conductor to a position in the second A direction beyond the one end, The microstrip line according to claim 3 or 4, wherein the second B pad extends from a position in the second A direction beyond the other end of the second strip conductor to a position in the second B direction beyond the other end.

6. The microstrip line according to claim 5 , wherein the pad section includes a plurality of the second A pads and a plurality of the second B pads.

7. 7. The microstrip line according to claim 1, wherein the pad portion has a thickness greater than a thickness of the first strip conductor and a thickness of the second strip conductor.

8. The microstrip line according to claim 1 , wherein the first strip conductor and the second strip conductor extend in parallel to each other.

9. 9. The microstrip line according to claim 1, further comprising a third strip conductor having the same width as the first strip conductor but a different length.

10. 10. The microstrip line according to claim 1, further comprising a fourth strip conductor having the same width as the second strip conductor but a different length.

11. 11. The microstrip line according to claim 1, wherein a high-frequency signal is input and the microstrip line is used for evaluating high-frequency characteristics.

12. An exposure mask having a shielding portion and a transmitting portion, for use in an exposure treatment of a metal foil-clad laminate, comprising: a shape of the shielding portion or a shape of the transmitting portion corresponds to a line pattern formed on the metal foil-clad laminate, The line pattern is a first strip conductor and a second strip conductor which are different in width from each other and extend linearly; a pad portion provided adjacent to the first strip conductor and the second strip conductor, An exposure mask comprising:

13. A step of preparing a microstrip line including a dielectric layer having a first surface and a second surface which are reverse to each other, a ground conductor provided on the first surface, and a first strip conductor and a second strip conductor which are provided on the second surface, have different widths, and extend linearly; measuring transmission characteristics of the first strip conductor and the second strip conductor to obtain a resonant frequency and an unloaded Q value; calculating an effective dielectric constant and an effective conductivity of the microstrip line based on the resonant frequency and the unloaded Q value; A method for evaluating a microstrip line, comprising:

14. The method for evaluating a microstrip line according to claim 13 , further comprising the step of calculating conductor losses corresponding to the first strip conductor and the second strip conductor based on the effective conductivity.

15. The method for evaluating a microstrip line according to claim 14, further comprising the step of calculating dielectric losses corresponding to the first strip conductor and the second strip conductor based on the conductor loss.

16. 16. The method for evaluating a microstrip line according to claim 15, further comprising the step of calculating a relative dielectric constant and a dielectric loss tangent of the dielectric layer based on the resonant frequency, the unloaded Q value, and the dielectric loss.

17. the microstrip line includes a pad portion provided on the second surface adjacent to the first strip conductor and electrically connected to the ground conductor; The step of acquiring the resonant frequency and the unloaded Q value includes: An operation of bringing a high-frequency probe having a signal terminal and a ground terminal close to the microstrip line; an operation of contacting the ground terminal with the pad portion and disposing the signal terminal at a position away from the first strip conductor; The method for evaluating a microstrip line according to any one of claims 13 to 16, comprising:

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