Circuit board measuring piece group and circuit board measuring method

Abstract

The invention provides a circuit board measuring piece set and a circuit board measuring method. The circuit board measurement method comprises the following steps: measuring a first measurement scattering parameter of a first measurement circuit board through a single port; measuring a second measurement scattering parameter of the second measurement circuit board through the single port; measuring a third measurement scattering parameter of a third measurement circuit board through a single port; according to the first measurement scattering parameter, the second measurement scattering parameter and the third measurement scattering parameter, calculating a characteristic impedance value, a tail end inductance impedance value and a propagation constant of the coaxial through hole of the circuit board; according to the circuit board measuring piece group and the circuit board measuring method, the electrical parameter of the coaxial through hole can be calculated by using the single-port measuring result, so that a reliable and simple verification tool and method are provided.

Description

Technical Field

[0001] This invention relates to a circuit board measurement assembly and a circuit board measurement method, which uses a single-sided, single-port measurement method and calculates the electrical parameters of the circuit board based on the measurement results. Background Technology

[0002] In existing multilayer circuit boards, coaxial vias are commonly used to transmit signals between upper and lower layers due to their excellent electromagnetic shielding properties. With the increasing speed and frequency of signals, the electrical parameters of coaxial vias can affect the integrity of the transmitted signal, thus requiring greater consideration of their electrical parameters.

[0003] In existing technologies, obtaining the electrical parameters of coaxial through-holes requires the preparation of equipment capable of double-sided measurement and the use of two-port instruments (such as network analyzers) for measurement. This requires additional investment in equipment and instruments, and the configuration of the equipment and the measurement process are also relatively complex. Summary of the Invention

[0004] At least one embodiment of the present invention provides a circuit board measurement kit, which provides a measurement kit that can be used for single-sided, single-port measurement to calculate the electrical parameters of the coaxial vias of the circuit board.

[0005] The circuit board measurement assembly provided in at least one embodiment of the present invention includes three measurement circuit boards. Each measurement circuit board includes four circuit layers, conductive pillars, a metal cylinder, and a transmission line. The four circuit layers are stacked on top of each other. The four circuit layers are arranged from top to bottom as a first circuit layer, a second circuit layer, a third circuit layer, and a fourth circuit layer. The conductive pillars penetrate the four circuit layers and connect the first circuit layer and the fourth circuit layer. The metal cylinder extends from the third circuit layer to the fourth circuit layer and surrounds the conductive pillars. The transmission line is electrically connected to the conductive pillars. The surface of one of the four circuit layers is flush with the surface of the transmission line. In the first of these measurement circuit boards, the surface of the transmission line is flush with the surface of the first circuit layer and is electrically connected to the ground portion of the first circuit layer. A first measurement scattering parameter exists between the transmission line electrically connected to the first circuit layer and the fourth circuit layer. In the second of these measurement circuit boards, the surface of the transmission line is flush with the surface of the second circuit layer and is electrically connected to the ground portion of the second circuit layer. A second measurement scattering parameter exists between the transmission line electrically connected to the second circuit layer and the fourth circuit layer. In the third of these measurement circuit boards, the surface of the transmission line is flush with the surface of the third circuit layer and electrically connected to a metal cylinder. A third measurement scattering parameter exists between the transmission line electrically connected to the third circuit layer and the fourth circuit layer. The electrical parameters of the coaxial vias on the circuit board are calculated based on the first, second, and third measurement scattering parameters.

[0006] In at least one embodiment of the present invention, the circuit board measurement assembly further includes an auxiliary measurement circuit board. The auxiliary measurement circuit board includes four measurement circuit layers and a measurement metal cylinder. The four measurement circuit layers are stacked on top of each other. The four measurement circuit layers are arranged from top to bottom as a first measurement circuit layer, a second measurement circuit layer, a third measurement circuit layer, and a fourth measurement circuit layer. The measurement metal cylinder extends from the third measurement circuit layer to the fourth measurement circuit layer. The fourth measurement circuit layer contains a fourth measurement scattering parameter. The electrical parameters of the coaxial via are also calculated based on the fourth measurement scattering parameter.

[0007] In at least one embodiment of the present invention, the thickness of the auxiliary measurement circuit board is the same as the thickness of these measurement circuit boards. The first measurement circuit layer has the same thickness as these first circuit layers. The second measurement circuit layer has the same thickness as these second circuit layers. The third measurement circuit layer has the same thickness as these third circuit layers. The fourth measurement circuit layer has the same thickness as these fourth circuit layers. In the first of these measurement circuit boards, the transmission lines are located in the same plane as the first circuit layer. In the second of these measurement circuit boards, the transmission lines are located in the same plane as the second circuit layer.

[0008] In at least one embodiment of the invention, in the third of these measurement circuit boards, a recess is formed at the top of the metal cylinder. A transmission line connects to the recess to be flush with the surface of the third circuit layer.

[0009] At least one embodiment of the present invention provides a circuit board measurement method, which is suitable for calculating the electrical parameters of the coaxial vias of the circuit board based on single-sided, single-port measurement results.

[0010] The circuit board measurement method provided by at least one embodiment of the present invention includes: measuring a first measurement scattering parameter of a first measurement circuit board with a single port; measuring a second measurement scattering parameter of a second measurement circuit board with a single port; measuring a third measurement scattering parameter of a third measurement circuit board with a single port; and calculating the characteristic impedance value, end inductance value, and propagation constant of the coaxial via of the circuit board based on the first measurement scattering parameter, the second measurement scattering parameter, and the third measurement scattering parameter.

[0011] In at least one embodiment of the present invention, the steps of calculating the characteristic impedance value, end inductance impedance value, and propagation constant of the coaxial via include: a fourth measurement scattering parameter of a single-port measurement auxiliary measurement circuit board; calculating a first scattering parameter to remove the capacitance effect based on the first and fourth measurement scattering parameters; calculating a second scattering parameter to remove the capacitance effect based on the second and fourth measurement scattering parameters; calculating a third scattering parameter to remove the capacitance effect based on the third and fourth measurement scattering parameters; and calculating the characteristic impedance value, end inductance impedance value, and propagation constant of the coaxial via based on the first, second, and third scattering parameters. In at least one embodiment of the present invention, the characteristic impedance value, end inductance impedance value, and propagation constant are also obtained based on the coaxial via length, a first spacing, and a second spacing. The equivalent circuit of the third measurement circuit board is an equivalent coaxial via. The coaxial via length is defined as the length of the equivalent coaxial via. The equivalent circuit of the first measurement circuit board is an equivalent coaxial via electrically connected to a first equivalent inductor. The equivalent circuit of the second measurement circuit board is an equivalent coaxial through-hole electrical connection to the second equivalent inductor. The sum of the first spacing and the second spacing is defined as the length of the first equivalent inductor. The second spacing is defined as the length of the second equivalent inductor.

[0012] In at least one embodiment of the present invention, the third measurement circuit board includes four circuit layers, conductive pillars, a metal cylinder, and transmission lines. The four circuit layers are stacked on top of each other. The four circuit layers are arranged from top to bottom as a first circuit layer, a second circuit layer, a third circuit layer, and a fourth circuit layer. The conductive pillars penetrate the four circuit layers and connect the first circuit layer and the fourth circuit layer. The metal cylinder extends from the third circuit layer to the fourth circuit layer and surrounds the conductive pillars. The transmission lines electrically connect the conductive pillars and the metal cylinder, and the surface of the transmission lines is flush with the surface of the third circuit layer. The coaxial through-hole length is the length from the bottom surface of the metal cylinder to the bottom surface of the transmission line. In at least one embodiment of the present invention, the second spacing is the length from the bottom surface of the transmission line to the bottom surface of the second circuit layer.

[0013] In at least one embodiment of the present invention, the first spacing is the length extending from the bottom surface of the second circuit layer to the bottom surface of the first circuit layer.

[0014] Based on the above, the circuit board measurement assembly and circuit board measurement method disclosed in the above embodiments can indirectly calculate the electrical parameters of coaxial vias using the measurement results of a single-sided, single-port measurement. Compared with double-sided, double-port measurement, this simplifies the equipment configuration, the necessary functions of the instrument, and the complexity of the measurement. Attached Figure Description

[0015] To gain a more complete understanding of the embodiments and their advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein:

[0016] Figure 1This is a partial cross-sectional view of the circuit board;

[0017] Figure 2 This is a cross-sectional schematic diagram of a first measurement circuit board according to at least one embodiment of the present invention;

[0018] Figure 3 This is a cross-sectional schematic diagram of a second measurement circuit board according to at least one embodiment of the present invention;

[0019] Figure 4 This is a cross-sectional schematic diagram of a third measurement circuit board according to at least one embodiment of the present invention;

[0020] Figure 5 This is a cross-sectional schematic diagram of an auxiliary measurement circuit board according to at least one embodiment of the present invention;

[0021] Figure 6 This is a flowchart of a circuit board measurement method 600 according to at least one embodiment of the present invention;

[0022] Figure 7 yes Figure 6 A flowchart of the sub-steps of step S660 in the circuit board measurement method;

[0023] Figure 8 and Figure 9 Calculate respectively Figure 1 The calculation results of the real and imaginary parts of the characteristic impedance value of the circuit board; and

[0024] Figure 10 and Figure 11 Calculate respectively Figure 1 The calculation results of the attenuation constant and equivalent dielectric constant corresponding to the propagation constant of the circuit board.

[0025] Figure label:

[0026] 100: Circuit board

[0027] 111~116, 211~216, 311~316, 411~416: Line layer

[0028] 111a,112a,211a,212a,216a,316a,416a,511a,512a,516a: Signaling Department

[0029] 111b, 112b, 113b, 114b, 115b, 116b, 211b, 212b, 213b, 214b, 215b, 216b, 312b, 413b, 511b, 512b, 513b, 514b, 515b, 516b: Grounding part

[0030] 111c: Antenna section

[0031] 116a: Chip pad

[0032] 120, 220, 320, 420: Conductive pillars

[0033] 130, 230, 330, 430: Metal cylinder

[0034] 131,231,431,521: concave part

[0035] 140: Conductive via

[0036] 150: Blind Hole

[0037] 160: Solder resist layer

[0038] 200: First Measurement Circuit Board

[0039] 240, 340, 440: Transmission lines

[0040] 300: Second Measurement Circuit Board

[0041] 400: Third Measurement Circuit Board

[0042] 500: Auxiliary Measurement Circuit Board

[0043] 511~516: Measurement Line Layer

[0044] 520: Measuring Metal Cylinder

[0045] 600: Circuit Board Measurement Methods

[0046] d: Coaxial perforation length

[0047] d1: First spacing

[0048] d2: Second spacing

[0049] S 610, S 620, S 630, S 640, S 650, S 660: Steps S 661 to S 665: Sub-steps Detailed Implementation

[0050] In the following text, to clearly present the technical features of this application, the dimensions (e.g., length, width, thickness, and depth) of components (e.g., layers, films, substrates, and regions) in the accompanying drawings will be enlarged proportionally, and the number of some components may be reduced. Therefore, the description and explanation of the embodiments below are not limited to the number of components in the drawings or the size and shape of the components, but should cover the dimensions, shapes, and deviations thereof caused by actual manufacturing processes and / or tolerances. For example, a flat surface shown in the drawings may have rough and / or non-linear characteristics, and an acute angle shown in the drawings may be rounded. Therefore, the components shown in the accompanying drawings are primarily for illustration and are not intended to precisely depict the actual shape of the components, nor are they intended to limit the claims of this application. Secondly, terms such as "about," "approximately," or "substantially" appearing in this application not only cover explicitly stated numerical values ​​and ranges, but also cover the permissible deviation range that can be understood by someone skilled in the art to which this invention pertains, where such deviation range can be determined by errors that occur during measurement, such as those caused by limitations of the measurement system or process conditions. Furthermore, "approximately" can mean within one or more standard deviations of the aforementioned values, such as ±30%, ±20%, ±10%, or ±5%. The use of terms such as "approximately," "approximately," or "substantially" in this text allows for the selection of an acceptable range of deviations or standard deviations based on optical, etched, mechanical, or other properties, and does not apply to all of the aforementioned optical, etched, mechanical, and other properties using a single standard deviation.

[0051] Figure 1 This is a partial cross-sectional view of circuit board 100. (See attached diagram.) Figure 1 The circuit board 100 includes multiple circuit layers, conductive pillars 120, metal cylinders 130, conductive vias 140, blind vias 150, and solder mask 160. Regarding the aforementioned multiple circuit layers, this example describes six circuit layers 111 to 116, but is not limited to this. The six circuit layers 111 to 116 are arranged from top to bottom as circuit layer 111, circuit layer 112, circuit layer 113, circuit layer 114, circuit layer 115, and circuit layer 116.

[0052] Line layer 111 includes a signal section 111a, a ground section 111b, and an antenna section 111c. The signal section 111a is electrically connected to the antenna section 111c. Line layer 112 includes a signal section 112a and a ground section 112b. Line layer 113 includes a ground section 113b. Line layer 114 includes a ground section 114b. Line layer 115 includes a ground section 115b. Line layer 116 includes a chip pad 116a and a ground section 116b.

[0053] Conductive post 120 penetrates through circuit layers 111-116 and connects circuit layers 111 and 116. Conductive post 120 electrically connects the signal section 111a of circuit layer 111 to the chip pad 116a of circuit layer 116. Therefore, the signal of antenna section 111c can be transmitted via conductive post 120 to the chip (not shown) soldered on chip pad 116a. Conductive post 120 can be a solid or hollow structure; in this example, a hollow conductive post 120 is used for illustration.

[0054] A metal cylinder 130 extends from circuit layer 113 to circuit layer 116 and surrounds the conductive post 120. The outer wall of the metal cylinder 130 connects to circuit layers 113-116 for electrical connection with ground portions 113b-116b. The metal cylinder 130 shields signals transmitted on the conductive post 120 from mutual interference with circuit layers 113-116. The metal cylinder 130 and the conductive post 120 form a coaxial through-hole. In this example, a recess 131 is formed at the top of the metal cylinder 130. This recess 131 is similar to a stepped surface. That is, in Figure 1 In the partial cross-sectional view, the top surface and side surface of the metal cylinder 130 are substantially right angles. In some other embodiments, the top end of the metal cylinder 130 may not have a recess 131.

[0055] Conductive via 140 penetrates and connects to circuit layers 111-116. Conductive via 140 is electrically connected to ground portions 111b-116b. The structure of conductive via 140 can be similar to that of conductive post 120. In other words, conductive post 120 can be a conductive via. Blind via 150 is formed between circuit layers 111-112 and is electrically connected to ground portions 111b-112b. For example, multiple blind vias 150 can surround conductive post 120, thus shielding signals transmitted on conductive post 120 from mutual interference with circuit layers 111-112. Solder resist layer 160 is provided on a portion of the surface of circuit layers 111 and 116, but does not cover antenna portion 111c.

[0056] The electrical parameters of the coaxial vias of circuit board 100 can be obtained by performing circuit board measurement methods using a circuit board measurement assembly. The circuit board measurement assembly includes a first measurement circuit board, a second measurement circuit board, a third measurement circuit board, and an auxiliary measurement circuit board, wherein the structures of the first measurement circuit board, the second measurement circuit board, the third measurement circuit board, and the auxiliary measurement circuit board are similar to the structure of circuit board 100.

[0057] Figure 2 This is a schematic cross-sectional view of a first measurement circuit board 200 according to at least one embodiment of the present invention. (See attached diagram) Figure 2The first measurement circuit board 200 includes multiple circuit layers 211-216, conductive pillars 220, metal cylinders 230, and transmission lines 240. The six circuit layers 211-216 are arranged from top to bottom as circuit layer 211, circuit layer 212, circuit layer 213, circuit layer 214, circuit layer 215, and circuit layer 216.

[0058] Specifically, the materials and thicknesses of the circuit layers 211 to 216 are the same as those of the circuit layers 111 to 116, and the materials and thicknesses of the dielectric layers between the circuit layers 211 to 216 are also the same as those of the dielectric layers between the circuit layers 111 to 116.

[0059] Line layer 211 includes a signal section 211a and a ground section 211b. Line layer 212 includes a signal section 212a and a ground section 212b. Line layer 213 includes a ground section 213b. Line layer 214 includes a ground section 214b. Line layer 215 includes a ground section 215b. Line layer 216 includes a signal section 216a and a ground section 216b. The structure of this signal section 216a is similar to that of the chip pad 116a, that is, the signal section 216a can be a pad.

[0060] The conductive post 220 has a structure similar to the conductive post 120 and is electrically connected to the signal section 211a of the circuit layer 211 and the signal section 216a of the circuit layer 216. The metal cylinder 230 has a structure similar to the metal cylinder 130 and surrounds the conductive post 220. The metal cylinder 230 is electrically connected to the ground sections 213b to 216b. The top of the metal cylinder 230 may or may not have a recess 231, and there is no limitation. The transmission line 240 is located in the same plane as the circuit layer 211, and the surface of the transmission line 240 is flush with the surface of the circuit layer 211. The transmission line 240 is electrically connected to the conductive post 220 and the ground section 211b, so that the conductive post 220 and the ground section 211b of the circuit layer 211 are electrically connected.

[0061] Figure 3 This is a cross-sectional schematic diagram of the second measurement circuit board 300 according to at least one embodiment of the present invention. (See also...) Figure 3 The second measurement circuit board 300 includes multiple circuit layers 311-316, conductive pillars 320, metal cylinders 330, and transmission lines 340. The six circuit layers 311-316 are arranged from top to bottom as circuit layer 311, circuit layer 312, circuit layer 313, circuit layer 314, circuit layer 315, and circuit layer 316.

[0062] Specifically, the structure of the second measurement circuit board 300 is similar to that of the first measurement circuit board 200, and the materials and thicknesses of the circuit layers 311 to 316 are the same as those of the circuit layers 211 to 216, and the materials and thicknesses of the dielectric layers between the circuit layers 311 to 316 are also the same as those of the dielectric layers between the circuit layers 211 to 216.

[0063] The second measurement circuit board 300 differs from the first measurement circuit board 200 in that the transmission line 340 and the circuit layer 312 are located on the same plane, and the surface of the transmission line 340 is flush with the surface of the circuit layer 312. The transmission line 340 is electrically connected to the conductive post 320 and the ground portion 312b, so that the conductive post 320 and the ground portion 312b of the circuit layer 312 are electrically connected.

[0064] Figure 4 This is a cross-sectional schematic diagram of a third measurement circuit board 400 according to at least one embodiment of the present invention. (See attached diagram) Figure 4 The third measurement circuit board 400 includes multiple circuit layers 411-416, conductive pillars 420, metal cylinders 430, and transmission lines 440. The six circuit layers 411-416 are arranged from top to bottom as circuit layer 411, circuit layer 412, circuit layer 413, circuit layer 414, circuit layer 415, and circuit layer 416.

[0065] Specifically, the structure of the third measurement circuit board 400 is similar to that of the first measurement circuit board 200, and the materials and thicknesses of the circuit layers 411-416 are the same as those of the circuit layers 211-216, and the materials and thicknesses of the dielectric layers between the circuit layers 411-416 are also the same as those of the dielectric layers between the circuit layers 211-216. The top of the metal cylinder 430 may or may not have a recess 431, and there are no limitations on this.

[0066] The third measurement circuit board 400 differs from the first measurement circuit board 200 in that, when a recess 431 is formed at the top of the metal cylinder 430, the transmission line 440 connects the recess 431 of the metal cylinder 430 to the conductive post 420, and is flush with the surface of the circuit layer 413. When the recess 431 is not formed at the top of the metal cylinder 430, the transmission line 440 directly connects the side of the metal cylinder 430 to the conductive post 420, and is flush with the surface of the circuit layer 413. The transmission line 440 electrically connects the conductive post 420, the ground portion 413b, and the metal cylinder 430, so that the conductive post 420 and the ground portion 413b of the circuit layer 413 are electrically connected.

[0067] Figure 5 This is a cross-sectional schematic diagram of an auxiliary measurement circuit board 500 according to at least one embodiment of the present invention. (See attached diagram) Figure 5The auxiliary measurement circuit board 500 includes multiple measurement circuit layers 511-516 and a measurement metal cylinder 520. The six measurement circuit layers 511-516 are arranged from top to bottom as measurement circuit layer 511, measurement circuit layer 512, measurement circuit layer 513, measurement circuit layer 514, measurement circuit layer 515 and measurement circuit layer 516.

[0068] Specifically, the thickness of the auxiliary measurement circuit board 500 is the same as the thickness of the first measurement circuit board 200. The materials and thicknesses of the measurement circuit layers 511-516 are the same as those of circuit layers 211-216, and also the same as those of circuit layers 111-116. The materials and thicknesses of the dielectric layers between the measurement circuit layers 511-516 are also the same as those of the dielectric layers between circuit layers 211-216, and also the same as those of the dielectric layers between circuit layers 111-116.

[0069] Measurement circuit layer 511 includes a signal portion 511a and a ground portion 511b. Measurement circuit layer 512 includes a signal portion 512a and a ground portion 512b. Measurement circuit layer 513 includes a ground portion 513b. Measurement circuit layer 514 includes a ground portion 514b. Measurement circuit layer 515 includes a ground portion 515b. Measurement circuit layer 516 includes a signal portion 516a and a ground portion 516b. This signal portion 516a is similar to the chip pad 116a, that is, the signal portion 516a can be a pad. Measurement metal cylinder 520 extends from measurement circuit layer 513 to measurement circuit layer 516 and is electrically connected to the ground portions 513b to 516b of measurement circuit layers 513 to 516. The top end of measurement metal cylinder 520 may or may not have a recess 521, and there is no limitation.

[0070] Figure 6 This is a flowchart of a circuit board measurement method 600 according to at least one embodiment of the present invention. The following description of the circuit board measurement method 600 pertains to measuring circuit boards such as… Figures 2 to 5 The first measurement circuit board 200, the second measurement circuit board 300, the third measurement circuit board 400, and the auxiliary measurement circuit board 500 are shown, and the electrical parameters of the circuit board 100 are indirectly known based on the measurement results.

[0071] See Figure 6First, in step S610, the instrument and probe are calibrated so that the subsequent measurement surface is aligned with the tip of the probe. The instrument can be a network analyzer, and the probe can be a GSG (G round Signal Ground, GSG) probe, a GS (G round Signal, GS) probe, an SG (Signal Ground) probe, or an SGS (Signal G round Signal, SGS) probe.

[0072] In this embodiment, a network analyzer and a GSG probe are used to measure a single port. Specifically, a GSG probe calibration kit is used to calibrate the single port, and the calibration kit includes short circuit detection accessories, open circuit detection accessories, and load detection accessories.

[0073] See Figure 2 and Figure 6 Next, in step S620, a probe is used to measure the first measurement scattering parameter of the first measurement circuit board 200 at a single port. Specifically, the probe is used to measure the signal section 216a of the first measurement circuit board 200 to obtain the first measurement scattering parameter, wherein the first measurement scattering parameter is the input port reflection coefficient S. 11 That is, the probe inputs a measurement signal to the signal unit 216a, and also measures the reflected signal in the signal unit 216a.

[0074] See Figure 3 and Figure 6 Next, in step S630, a probe is used to measure the second measurement scattering parameter of the second measurement circuit board 300 at a single port. Specifically, the probe is used to measure the signal section 316a of the second measurement circuit board 300 to obtain the second measurement scattering parameter, which is also the input port reflection coefficient S. 11 That is, the probe inputs a measurement signal to the signal unit 316a, and also measures the reflected signal in the signal unit 316a.

[0075] See Figure 4 and Figure 6 Next, in step S640, a probe is used to measure the third measurement scattering parameter of the third measurement circuit board 400 at a single port. Specifically, the probe is used to measure the signal section 416a of the third measurement circuit board 400 to obtain the third measurement scattering parameter, which is also the input port reflection coefficient S. 11That is, the probe inputs a measurement signal to the signal unit 416a, and also measures the reflected signal in the signal unit 416a.

[0076] See Figure 5 and Figure 6 Next, in step S650, the fourth measurement scattering parameter of the auxiliary measurement circuit board 500 is measured using a probe single-port measurement. Specifically, the signal section 516a of the auxiliary measurement circuit board 500 is measured using a probe to obtain the fourth measurement scattering parameter, which is also the input port reflection coefficient S. 11 That is, the probe inputs a measurement signal to the signal unit 516a, and also measures the reflected signal in the signal unit 516a.

[0077] It is worth mentioning that the above steps S620 to S650 are not in any particular order. Step S650 can be performed first to measure the auxiliary measurement circuit board 500, and then steps S620 to S640 can be performed to measure the first measurement circuit board 200 to the third measurement circuit board 400.

[0078] Further, see Figure 1 and Figure 5 Compared to the circuit board 100, the auxiliary measurement circuit board 500 lacks conductive pillars, creating an open circuit between the signal section 516a and the signal section 511a. Therefore, the equivalent circuit of the auxiliary measurement circuit board 500 with the signal section 516a as its input terminal is the equivalent capacitance, and the fourth measurement scattering parameter of the measurement line layer 516 is the measurement scattering parameter of the equivalent capacitance. Specifically, the equivalent circuit of the signal section 516a of the auxiliary measurement circuit board 500 can correspond to the equivalent capacitance formed by the chip pads 116a of the circuit board 100. Thus, the fourth measurement scattering parameter can correspond to the measurement scattering parameter of the equivalent capacitance of the circuit board 100.

[0079] See Figure 1 and Figure 4 In the third measurement circuit board 400, since the transmission line 440 is electrically connected to the conductive post 420, the ground portion 413b, and the metal cylinder 430, and is flush with the surface of the circuit layer 413, a short circuit is formed at the corresponding position on the surface of the circuit layer 413 for the conductive post 420. Therefore, the equivalent circuit of the third measurement circuit board 400 with the signal portion 416a as the input terminal is an equivalent coaxial via, and the third measurement scattering parameter between the transmission line 440 and the circuit layer 416 is the measurement scattering parameter of the equivalent coaxial via. In particular, the equivalent circuit of the third measurement circuit board 400 can correspond to the coaxial via of the circuit board 100 (the metal cylinder 130 and part of the conductive post 120 inside the metal cylinder 130). Thus, the third measurement scattering parameter can correspond to the measurement scattering parameter of the coaxial via of the circuit board 100. See also Figure 1 and Figure 3In the second measurement circuit board 300, since the transmission line 340 is electrically connected to the conductive post 320 and the ground portion 312b, and the surface and bottom surface of the transmission line 340 are respectively flush with the surface and bottom surface of the circuit layer 312, the conductive post 320 forms a short circuit at the corresponding position of the circuit layer 312. Therefore, the equivalent circuit of the second measurement circuit board 300 with the signal portion 316a as the input terminal is an equivalent coaxial via electrically connected to an equivalent inductor, and the second measurement scattering parameter between the transmission line 340 and the circuit layer 316 is the measurement scattering parameter of the equivalent coaxial via and the equivalent inductor. In particular, the equivalent circuit of the second measurement circuit board 300 can correspond to the coaxial via and the equivalent inductor of the circuit board 100.

[0080] It should be noted that, in this example, this equivalent inductance extends from the recess 131 of the metal cylinder 130 to the bottom surface of the circuit layer 112. That is, this equivalent inductance is the inductance extending from the recess 131 of the metal cylinder 130 corresponding to... Figure 4 The bottom surface of transmission line 440 extends to the bottom surface of line layer 112. Thus, the second measured scattering parameter can correspond to the measured scattering parameter of the coaxial via and equivalent inductance of circuit board 100.

[0081] See Figure 1 and Figure 2 In the first measurement circuit board 200, since the transmission line 240 is electrically connected to the conductive post 220 and the ground portion 211b, and the surface and bottom surface of the transmission line 240 are respectively flush with the surface and bottom surface of the circuit layer 211, the conductive post 220 forms a short circuit at the corresponding position of the circuit layer 211. Therefore, the equivalent circuit of the first measurement circuit board 200 with the signal portion 216a as the input terminal is an equivalent coaxial via electrically connected to an equivalent inductor, and the first measurement scattering parameter between the transmission line 240 and the circuit layer 216 is the measurement scattering parameter of the equivalent coaxial via and the equivalent inductor. In particular, the equivalent circuit of the first measurement circuit board 200 can correspond to the coaxial via and the equivalent inductor of the circuit board 100.

[0082] It should be noted that, in this example, this equivalent inductance extends from the recess 131 of the metal cylinder 130 to the bottom surface of the circuit layer 111. That is, this equivalent inductance is the inductance extending from the recess 131 of the metal cylinder 130 corresponding to... Figure 4 The bottom surface of transmission line 440 extends to the bottom surface of line layer 111. Thus, the first measured scattering parameter can correspond to the measured scattering parameter of the coaxial via and equivalent inductance of circuit board 100.

[0083] See Figure 6Next, in step S660, the processor calculates the characteristic impedance value, first end inductance value, second end inductance value, and propagation constant of the coaxial via of the circuit board 100 based on the first measured scattering parameter, the second measured scattering parameter, and the third measured scattering parameter. The first end inductance value is the impedance of the first equivalent inductance electrically connected to the end of the coaxial via (the equivalent inductance extending from the recess 131 of the metal cylinder 130 to the bottom surface of the circuit layer 111), and the second end inductance value is the impedance of the second equivalent inductance electrically connected to the end of the coaxial via (the equivalent inductance extending from the recess 131 of the metal cylinder 130 to the bottom surface of the circuit layer 112). It should be noted that the processor has computational capabilities and can be a processor within a network analyzer or a processor within a computer; there are no limitations.

[0084] The structure of the first measurement circuit board 200 is similar to that of the conductive post 120 of the circuit board 100 grounded on the circuit layer 111, the structure of the second measurement circuit board 300 is similar to that of the conductive post 120 of the circuit board 100 grounded on the circuit layer 112, the structure of the third measurement circuit board 400 is similar to that of the conductive post 120 of the circuit board 100 grounded on the circuit layer 113, and the structure of the auxiliary measurement circuit board 500 is similar to that of the conductive post 120 of the circuit board 100 forming an open circuit with the circuit layer 116. Therefore, without considering process errors, the first, second, third, and fourth measured scattering parameters are similar to the measurement results of the circuit board 100 in their respective equivalent circuits.

[0085] Figure 7 yes Figure 6 The flowchart shows the sub-steps S661 to S665 of step S660 in the circuit board measurement method 600. See also... Figure 7 Step S660 includes sub-steps S661 to S665. In sub-step S661, the processor calculates the de-embedding coefficients based on the fourth measurement scattering parameters. The formula for the de-embedding coefficients is as follows:

[0086]

[0087] Where e 11 e 21 Γ is the de-embedding coefficient. p a d The fourth scattering parameter is then used. Next, in substep S662, the processor calculates a first scattering parameter to remove the capacitance effect based on the first and fourth scattering parameters, where the fourth scattering parameter is used to calculate the de-embedding coefficient. The formula for the first scattering parameter is as follows:

[0088]

[0089] Where Γ L 1 represents the first scattering parameter, Γ L 1,e m b e d This is the first scattering parameter measured.

[0090] Next, in substep S663, the processor calculates a second scattering parameter to remove the capacitance effect based on the second and fourth measured scattering parameters, wherein the fourth measured scattering parameter is used to calculate the de-embedding coefficient. The formula for the second scattering parameter is as follows:

[0091]

[0092] Where Γ L 2 represents the second scattering parameter, Γ L 2,e m b e d This is the second scattering parameter to be measured.

[0093] Next, in substep S664, the processor calculates the third scattering parameter to remove the capacitance effect based on the third and fourth measured scattering parameters, where the fourth measured scattering parameter is used to calculate the de-embedding coefficient. The formula for the third scattering parameter is as follows:

[0094]

[0095] Where Γ L 3 represents the third scattering parameter, Γ L 3,e m b e d This is the third scattering parameter to be measured.

[0096] Next, in sub-step S665, the processor calculates the characteristic impedance value, first end inductance value, second end inductance value, and propagation constant of the coaxial via of the circuit board 100 based on the first scattering parameter, the second scattering parameter, the third scattering parameter, the coaxial via length d, the first pitch d1, and the second pitch d2. Specifically, the coaxial via length d is defined as the length of the equivalent coaxial via, the sum of the first pitch d1 and the second pitch d2 is defined as the length of the first equivalent inductance, and the second pitch d2 is defined as the length of the second equivalent inductance. Figure 4As shown in the third measurement circuit board 400, the coaxial through-hole length d is the length from the bottom surface of the metal cylinder 430 to the bottom surface of the transmission line 440; the second spacing d2 is the length from the bottom surface of the transmission line 440 to the bottom surface of the circuit layer 412; and the first spacing d1 is the length from the bottom surface of the circuit layer 412 to the bottom surface of the circuit layer 411.

[0097] The formulas for the characteristic impedance, inductive impedance at the first end, inductive impedance at the second end, and propagation constant of the coaxial through-hole are shown below:

[0098]

[0099] Z L1 =pZ L2

[0100]

[0101]

[0102] Z c Z is the characteristic impedance value. L 1 represents the impedance value of the first terminal inductor, Z L 2 is the impedance value of the second end inductor, p is the ratio of the length of the first equivalent inductor to the length of the second equivalent inductor, γ is the propagation constant, t is the transmission line propagation factor, and Γ is the reflection coefficient of the equivalent coaxial aperture.

[0103] Figure 8 and Figure 9 Calculate respectively Figure 1 The calculation results of the real and imaginary parts of the characteristic impedance value of circuit board 100 are shown below. Figure 8 and Figure 9 The X-axis represents the frequency corresponding to the characteristic impedance value, and the Y-axis represents the real and imaginary parts of the characteristic impedance value, respectively. The solid line represents the calculation result without removing the capacitance effect, while the dashed line represents the calculation result with removing the capacitance effect.

[0104] Figure 10 and Figure 11 Calculate respectively Figure 1 The calculation results of the attenuation constant and equivalent dielectric constant corresponding to the propagation constant of circuit board 100. (See attached document.) Figure 10 and Figure 11 The X-axis represents the frequency corresponding to the attenuation constant and the equivalent dielectric constant, respectively, and the Y-axis represents the attenuation constant and the equivalent dielectric constant, respectively. The solid line represents the calculation result without removing the capacitance effect, while the dashed line represents the calculation result with removing the capacitance effect.

[0105] from Figures 8 to 11As can be seen, by eliminating the capacitance and inductance effects through the above steps, stable and convergent results can be calculated in the frequency range of 5 GHz to 110 GHz, and these results approximate the electrical parameters of the designed coaxial via. Therefore, the combination of the circuit board measurement components and the circuit board measurement method of this invention can indeed calculate the electrical parameters of the coaxial via of circuit board 100, thereby verifying the impedance matching of the coaxial via and the changes in amplitude and phase of electromagnetic wave transmission within the coaxial via. Furthermore, the circuit board measurement components and the circuit board measurement method of this invention can also be applied to circuit boards with four, five, or more than six circuit layers without limitation. Each of these circuit boards can also be measured using the first measurement circuit board 200, the second measurement circuit board 300, the third measurement circuit board 400, and the auxiliary measurement circuit board 500.

[0106] It is worth mentioning that the circuit board measurement kit and circuit board measurement method of the present invention can be applied to circuit boards 100 where the signal section 111a of the circuit layer 111 is a single pad or transmission line structure. When the signal section 111a is a single pad, the coaxial via and the single pad form an I-type structure. Using the circuit board measurement kit and circuit board measurement method of the present invention, the electrical parameters of the I-type structure of the circuit board can be obtained. Furthermore, the circuit board measurement kit and circuit board measurement method of the present invention can also be applied to technical fields such as semiconductor silicon through-hole, glass through-hole, three-dimensional chip, or high-density packaging, providing a convenient and reliable verification tool and method compared to double-sided dual-port measurement.

[0107] In summary, the circuit board measurement kit and circuit board measurement method disclosed in the above embodiments can provide a single-sided and single-port measurement method, thereby indirectly calculating the electrical parameters of the coaxial vias of the circuit board. It simplifies the configuration of equipment, the necessary functions of instruments, and the complexity of measurement, and provides a reliable verification tool and method.

[0108] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Those skilled in the art to which this invention pertains may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A circuit board measuring assembly, characterized in that, include: Three measurement circuit boards, each including: The four circuit layers are stacked on top of each other, and the order of these four circuit layers from top to bottom is the first circuit layer, the second circuit layer, the third circuit layer and the fourth circuit layer; Conductive pillars penetrate the four circuit layers and connect the first circuit layer to the fourth circuit layer; A metal cylinder extending from the third circuit layer to the fourth circuit layer and surrounding the conductive pillar; and A transmission line is electrically connected to the conductive post, wherein the surface of one of the four circuit layers is flush with the surface of the transmission line; In the first of the plurality of measurement circuit boards, the surface of the transmission line is flush with the surface of the first line layer and is electrically connected to the ground portion of the first line layer, wherein a first measurement scattering parameter exists between the transmission line electrically connected to the first line layer and the fourth line layer. In the second of the plurality of measurement circuit boards, the surface of the transmission line is flush with the surface of the second line layer and is electrically connected to the ground portion of the second line layer, wherein a second measurement scattering parameter exists between the transmission line electrically connected to the second line layer and the fourth line layer. In the third of the plurality of measurement circuit boards, the surface of the transmission line is flush with the surface of the third circuit layer and is electrically connected to the metal cylinder, wherein a third measurement scattering parameter exists between the transmission line electrically connected to the third circuit layer and the fourth circuit layer. The electrical parameters of the coaxial vias on the circuit board are calculated based on the first measured scattering parameter, the second measured scattering parameter, and the third measured scattering parameter.

2. The circuit board measurement assembly as described in claim 1, characterized in that, Also includes: Auxiliary measurement circuit board, including: The four measurement circuit layers are stacked on top of each other, and the order of the four measurement circuit layers from top to bottom is the first measurement circuit layer, the second measurement circuit layer, the third measurement circuit layer and the fourth measurement circuit layer. as well as The measuring metal cylinder extends from the third measuring circuit layer to the fourth measuring circuit layer; The fourth measurement line layer has a fourth measurement scattering parameter, and the electrical parameter of the coaxial via is also calculated based on the fourth measurement scattering parameter.

3. The circuit board measurement assembly as described in claim 2, characterized in that, The thickness of the auxiliary measurement circuit board is the same as the thickness of the plurality of measurement circuit boards. The thickness of the first measurement circuit layer is the same as the thickness of the plurality of first circuit layers. The thickness of the second measurement circuit layer is the same as the thickness of the plurality of second circuit layers. The thickness of the third measurement circuit layer is the same as the thickness of the plurality of third circuit layers. The thickness of the fourth measurement circuit layer is the same as the thickness of the plurality of fourth circuit layers. In the first of the plurality of measurement circuit boards, the transmission line is located on the same plane as the first line layer; In the second of the plurality of measurement circuit boards, the transmission line is located on the same plane as the second line layer.

4. The circuit board measurement assembly as described in claim 1, characterized in that, In the third of the plurality of measurement circuit boards, a recess is formed at the top of the metal cylinder, and the transmission line connects to the recess to be flush with the surface of the third circuit layer.

5. A circuit board measurement method, characterized in that, include: The first measurement scattering parameter of the first measurement circuit board is measured using a single-port measurement. The second measurement scattering parameter of the second measurement circuit board is measured using a single-port measurement. The third measurement scattering parameter of the single-port measurement third measurement circuit board; The characteristic impedance, end inductance, and propagation constant of the coaxial via on the circuit board are calculated based on the first, second, and third scattering parameters.

6. The circuit board measurement method as described in claim 5, characterized in that, The steps for calculating the characteristic impedance value, the end inductance impedance value, and the propagation constant of the coaxial via include: The fourth measurement scattering parameter of the single-port measurement auxiliary measurement circuit board; The first scattering parameter after removing the capacitance effect is calculated based on the first measured scattering parameter and the fourth measured scattering parameter. The second scattering parameter, after removing the capacitance effect, is calculated based on the second and fourth measured scattering parameters. The third scattering parameter, after removing the capacitance effect, is calculated based on the third and fourth measured scattering parameters; and The characteristic impedance value, the end inductance value, and the propagation constant of the coaxial perforation are calculated based on the first scattering parameter, the second scattering parameter, and the third scattering parameter.

7. The circuit board measurement method as described in claim 5, characterized in that, The characteristic impedance value, the terminal inductance impedance value, and the propagation constant are also obtained based on the coaxial via length, the first spacing, and the second spacing. The equivalent circuit of the third measurement circuit board is an equivalent coaxial via, the coaxial via length is defined as the length of the equivalent coaxial via, the equivalent circuit of the first measurement circuit board is the equivalent coaxial via electrically connected to the first equivalent inductor, the equivalent circuit of the second measurement circuit board is the equivalent coaxial via electrically connected to the second equivalent inductor, the sum of the first spacing and the second spacing is defined as the length of the first equivalent inductor, and the second spacing is defined as the length of the second equivalent inductor.

8. The circuit board measurement method as described in claim 7, characterized in that, The third measurement circuit board includes: The four circuit layers are stacked on top of each other, and the order of these four circuit layers from top to bottom is the first circuit layer, the second circuit layer, the third circuit layer and the fourth circuit layer; Conductive pillars penetrate the four circuit layers and connect the first circuit layer to the fourth circuit layer; A metal cylinder extending from the third circuit layer to the fourth circuit layer and surrounding the conductive pillar; and The transmission line electrically connects the conductive post to the metal cylinder, and the surface of the transmission line is flush with the surface of the third circuit layer. The length of the coaxial perforation is the length from the bottom surface of the metal cylinder to the bottom surface of the transmission line.

9. The circuit board measurement method as described in claim 8, characterized in that, The second spacing is the length extending from the bottom surface of the transmission line to the bottom surface of the second line layer.

10. The circuit board measurement method as described in claim 8, characterized in that, The first spacing is the length extending from the bottom surface of the second circuit layer to the bottom surface of the first circuit layer.

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