JP2009520960A - Measuring device for determining characteristic line parameters by measuring scattering parameters - Google Patents

Abstract

The present invention determines characteristic line parameters by measuring S-parameters as a function of the frequency of an electrical signal line (14) that achieves an increased measurement bandwidth, i.e.> 4 GHz. It relates to a measurement mechanism for the purpose.
To achieve this, an electrical signal line to be tested alternately has several proximity signal lines (12) with one side connected to ground and the other side open.
[Selection] Figure 4

Description

  The present invention relates to a measuring device for determining characteristic line parameters by measuring scattering parameters (S parameters) as a function of the frequency of the electrical signal lines.

  Measuring model-to-hardware correlation at all packaging levels is essential in today's high-performance computer development process. Different measurement techniques in the time and frequency domains require different measurement settings and test site designs. One of the requirements for the test location is that it is equivalent to the product. Therefore, the transmission lines on the chip need to be measured in the product, such as power and ground wiring distributed in all metal layers on the chip. In addition, the objective is to measure not only a single transmission line, but also products such as wiring channel applications. This is essential to express the actual signal coupling state on the chip and the shielding effect of the metal layer between the upper metal layer and the semiconductor substrate.

  A known measurement technique is the so-called S-parameter measurement, see Zinke / Brunswig, “Lehrbuch der Hochfrenztechnik”, Springer-Verlag, 1989. The S parameter is the reflection and transmission coefficient of the network of n ports. For example, corresponding to a single transmission line is a two-port network characterized by a 2 × 2 S-parameter matrix.

  A two-port network is described by the following relationship.

Where S ₁₁ , S ₂₂ , S ₁₂ and S ₂₁ are S parameters, ie
S ₁₁ = input reflection coefficient with output port terminated by matched load,
S ₂₂ = output reflection coefficient with input terminated by matched load,
S ₁₂ = reverse (insertion) gain with input port terminated by matched load,
S ₂₁ = order (insertion) gain where the output port is terminated by a matched load;
Variables a1, a2 and b1, b2 are complex voltage waves incident on and reflected from the first and second ports of the two-port network.

  In this case, S-parameter measurement is an advantageous measurement technique because S-parameters are easier to measure and act at higher frequencies than other types of parameters.

  In addition, different methods are known in the state of the art for extracting other characteristic frequency dependent line parameters such as characteristic impedance Z (f) or propagation constant γ (f) from S-parameter measurements, and these Parameters can be easily obtained from S-parameter measurements. Thomas-Michael Winkel, Rohit Sagar Dutta, Harmut Graskin (Harmut Grabinski), “An Accurate Determination of the "Parameter Measurements", IEEE Multi-Chip Module MCMC '96, p. 190-195, February 1996, Thomas-Michael Winkel, "Unters". Uchung der Kopplung zwischen Leitungen auf Silizium-Substraten unscherichilitcher Leitfaheigkeit unter Vernund breibander.

  One special requirement for high frequency S-parameter measurements in this case is that the transmission line is not connected to any active device on the chip. For this reason, parallel signal lines will float if they are not connected to any driver and receiver. A problem arises when the parallel lines on the test site must be connected to some point where the driver, receiver, and transistor are not present.

  One option is to leave both sides of the signal line open, but the floating line does not correspond to the product and thus alters the measurement results.

  A second option is to connect both ends of parallel signal lines to ground. In this case, all signal lines act as ground lines, which also do not correspond to products.

  In principle, the driver has a low impedance and the receiver has a high impedance. Therefore, a third option is to connect one of the parallel signal lines and leave the opposite side open. This option mimics the product, but the problem that arises here is that high frequency measurements are band limited below 4 GHz. This is because the higher the frequency range, the different measurement ports exhibit different electrical behaviors on both ports. Some ports deal with open parallel lines, while the opposite ports deal with grounded parallel lines. As a result, for a frequency> 4 GHz, only one signal line mode will not be excited in the test structure.

  As evidenced from the above description, it would be desirable to provide a measurement system for determining S-parameters as a function of the frequency of the electrical signal line that does not suffer from the above-mentioned drawbacks and leads to a significant gain in measurement bandwidth.

  The present invention relates to a measuring device for determining characteristic transmission line parameters by measuring S-parameters as a function of the frequency of the electrical signal line that achieves an increased measurement bandwidth, i.e.> 4 GHz. .

  The measuring device according to the invention is characterized by what is defined in the independent claim 1.

  Advantageous embodiments of the invention are defined in the dependent claims.

Progressive measuring device, the test subject signal lines, namely comprising a measuring line, and several of the proximity signal line, measuring line and the proximity signal line, the port 1 of the two-port network (S ₁₁₎ and Port 2 It has a first end and a second end representing (S ₂₂ ). According to the present invention, one end of each proximity signal line is terminated with a low impedance, and the other end of each proximity signal line is terminated with a high impedance. The number of proximate signal lines having a low impedance at the first end or the second end, respectively, is terminated by a low impedance and a high impedance, respectively, the first end or the second end. Is equal to or approximately equal to the number of adjacent signal lines having high impedance.

  As a result of the special connection pattern, both ports appear at least nearly identical. Thus, only one signal mode is excited and the frequency bandwidth is significantly increased.

  According to one aspect of the invention, the low impedance is formed by a closed end line (connected to ground) and the high impedance is formed by an open end line.

  According to still another feature of the present invention, the measurement lines are arranged in a plane, and the proximity signal lines are arranged in a wiring pattern body or a parallel arrangement in a plane with respect to the measurement lines.

  Preferably, the proximity signal lines arranged immediately adjacent to each other have different impedances at their first and second ends so that the first end and the first of all the proximity signal lines are The two ends are alternately terminated by a low impedance and a high impedance, respectively. This results in an alternating arrangement on port 1 and port 2, respectively. This means that both ports have the same appearance and as a result the frequency bandwidth increases more than 20 GHz.

  According to another feature of the invention, the number of adjacent signal lines on both sides of the measurement line is equal.

  Further, the proximity signal lines arranged directly adjacent to the measurement line may have different or identical impedances at their first and second ends.

  According to still another feature of the present invention, the measurement line and the proximity signal line are signal lines in the multilayer chip, and the direction of the signal line between the two adjacent layers is rotated by 90 °. The proximity signal lines are arranged in a parallel arrangement in the measurement layer of the same layer, and the signal lines in the layer adjacent to the measurement layer, that is, the proximity layer lines are also in a parallel arrangement, and the first end and Arranged with different impedances at the second end, the first and second ends of all adjacent layer lines are terminated by a low impedance and a high impedance, respectively. The number of proximity layer lines having a low impedance at the first end or the second end is equal to the number of proximity layer lines having a high impedance at the first end or the second end, or Almost equal.

  Preferably, the proximity signal lines arranged immediately adjacent to each other have different impedances at their first and second ends, respectively, so that the first ends of all the proximity layer lines and The second end is alternately terminated by a low impedance and a high impedance, respectively. This alternating arrangement of adjacent layer lines relative to the alternating arrangement of adjacent signal lines leads to a significant gain in measurement bandwidth. Experiments have shown that this progressive arrangement of wiring on the chip increases the bandwidth to 20 GHz.

  According to another feature of the invention, the measurement lines and the proximity lines are arranged as a bundle.

  In order to ensure that both ports of the bundle have approximately the same appearance, the ends of the low and high impedance proximity signal lines are each arranged identically or substantially identically with respect to the virtual cross-sectional area of the bundle.

  Further objects, advantages and features of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

  FIG. 1 shows a schematic view of a multilayer chip 10 having an asymmetric connection pattern of signal lines (state of the art).

  In order to represent the actual signal coupling state on the chip 10, a further signal line 12, a so-called proximity signal line, is added adjacent to the signal line 14 under test in the same layer, the so-called measurement line.

  Proximity signal line 12 is connected to the ground on one side 16, here port 1, via vias to mimic the driver, and on the other side 18, here port 2, remains open and mimics the receiver.

  In order to express the shielding effect of the metal layer between the top metal layer and the semiconductor substrate, a further signal line 20, a so-called proximity layer line, has been added in the bottom metal layer. Further, all the proximity signal lines 20 are connected to the ground on one side and opened on the other side.

As a result, as shown in FIG. 2, the measured reflection parameters S ₁₁ and S ₂₂ no longer match for high frequencies.

  Due to random and systematic measurement errors, the measurement uncertainty with respect to size is usually around 3%. For frequencies> 4 GHz, the difference between both reflection parameters is greater than this value with respect to magnitude and phase. This means that more modes than just one signal line mode are excited in the test structure. Therefore, all extracted transmission line parameters are valid up to 4 GHz.

In order to increase the frequency bandwidth of the extracted data, the test site design needs to be modified according to the present invention. Ensure that the measured reflection parameters for port 1 (S ₁₁ ) 16 and port 2 (S ₂₂ ) 18 are approximately equal. This goal can be achieved by making ports 16 and 18 symmetrical from an electrical point of view.

As shown in FIG. 4, the symmetry of the ports is that each of the adjacent adjacent signal lines 12 is connected to the ground by the port 1 (S ₁₁ ) 16 and all other adjacent adjacent signal lines 12 are connected to the port 1 (S ₁₁ ) achieved by leaving open at 16. In the port 2 (S ₂₂ ) 18, the adjacent proximity signal line 12 that is left open at the port 1 (S ₁₁ ) 16 is grounded at the port 2 (S ₂₂ ) 18. All other proximity layer lines 20 in the other metal layers are alternately connected to ground as well.

As a result of this change, the reflection parameters measured for port 1 (S ₁₁ ) 16 and port 2 (S ₂₂ ) 18 are approximately the same as shown in FIG. 5 for magnitude and as shown in FIG. 6 for phase. In the frequency range up to at least 20 GHz. Some differences between the measured two reflection parameters are common, but as a criterion for good measurement, this difference is that the expected measurement uncertainty for magnitude is greater than 0.03 db (at 20 GHz) Must not exceed 2 ° in terms of phase (at 20 GHz).

It is the schematic of the multilayer chip | tip which has the connection pattern of a signal line based on the latest technology. FIG. 3 shows the magnitudes of measured reflection parameters S ₁₁ and S ₂₂ on port 1 and port 2 according to FIG. FIG. 3 shows the phases of measured reflection parameters S ₁₁ and S ₂₂ on port 1 and port 2 according to FIG. It is the schematic of the multilayer chip | tip which has the connection pattern of the signal line which concerns on this invention. FIG. 5 shows the magnitudes of the measured reflection parameters S ₁₁ and S ₂₂ for the port symmetry test location according to FIG. FIG. 5 is the phase of measured reflection parameters S ₁₁ and S ₂₂ for the port symmetry test location according to FIG.

Explanation of symbols

10 Multilayer chip 12 Proximity signal line 14 Measurement line 16 Port 1
18 Port 2
20 Proximity layer line

Claims (12)

A measuring device for determining characteristic line parameters by measuring a scattering parameter (S parameter) as a function of the frequency of a measuring line (14) which is an electrical signal line, the measuring line comprising several measuring lines A proximity signal line (12), wherein the measurement line (14) and the proximity signal line (12) each have a first end and a second end;
One end of each proximity signal line (12) is terminated with a low impedance, and the other end of each proximity signal line (12) is terminated with a high impedance, so that all of the proximity signal lines (12) are terminated. The number of proximity signal lines (12) having the first end and the second end terminated by a low impedance and a high impedance, respectively, and having a low impedance at the first end or the second end is: Measuring device characterized in that it is equal to or approximately equal to the number of proximity signal lines (12) having a high impedance at the first end or the second end.   The measurement apparatus according to claim 1, wherein the low impedance is formed by a closed end line (connected to a ground), and the high impedance is formed by an open end line.   The said measurement line (14) is a planar arrangement, The said proximity signal line (12) is arrange | positioned by the wiring pattern body in the surface with respect to the said measurement line (14), The characterized by the above-mentioned. The measuring device described in 1.   3. The measurement line (14) according to claim 1 or 2, characterized in that the measurement line (14) is a planar arrangement and the proximity signal lines (12) are arranged in a parallel arrangement in a plane relative to the measurement line (14). The measuring device described.   5. Measuring according to claim 1, characterized in that the proximity signal lines (12) arranged immediately adjacent to each other have different impedances at their first and second ends, respectively. apparatus.   6. Measuring device according to claim 1, characterized in that the number of adjacent signal lines (12) on both sides of the measuring line (14) is equal.   The proximity signal lines (12) arranged immediately adjacent to the measurement line (14) have different impedances at their first and second ends, respectively. The measuring apparatus according to 1 to 6.   The proximity signal lines (12) arranged immediately adjacent to the measurement line (14) have the same impedance at their first and second ends, respectively. Item 7. The measuring device according to items 1 to 6.   The measurement line (14) and the proximity signal line (12) are signal lines in the multilayer chip (10), and the direction of the signal line between two adjacent layers is rotated by 90 °. (14) and the proximity signal line (12) are arranged in parallel in the measurement layer of the same layer, and the proximity layer line (20) which is a signal line in a layer adjacent to the measurement layer is Arranged in a parallel arrangement having different impedances at the first end and the second end, respectively, the first and second ends of all adjacent layer lines (20) have low impedance, respectively. And the number of adjacent layer lines (20) terminated with a high impedance and having a low impedance at the first end or the second end has a high impedance at the first end or the second end. Proximity layer line (2 The number or equal to), or wherein the substantially equal, the measurement apparatus according to claims 1 8.   10. Measuring device according to claim 9, characterized in that the adjacent layer lines (20) arranged directly adjacent to each other have different impedances at their first and second ends.   3. The measuring device according to claim 1, wherein the measuring line (14) and the proximity signal line (12) are arranged as a bundle.   12. The measuring apparatus according to claim 11, wherein in the virtual cross-sectional area of the bundle, the end portions of the proximity signal lines (14) having a low impedance and a high impedance are respectively arranged in the same or substantially the same manner. .

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