A three-dimensional metal isolation wiring structure and wiring method for preventing crosstalk

Abstract

The present application belongs to the field of chip design technology, and discloses a three-dimensional metal isolation wiring structure and wiring method for preventing crosstalk. The wiring structure includes a first metal wire, a second metal wire, a third metal wire, and a signal transmission line for transmitting high-speed analog signals; the first metal wire and the second metal wire are respectively arranged on the left and right sides of the signal transmission line; the third metal wire is arranged directly below the signal transmission line; the first metal wire, the second metal wire, and the third metal wire are all grounded. The present application can prevent the occurrence of crosstalk in all directions and effectively ensure the integrity of high-speed and high-precision analog signals.

Description

Technical Field

[0001] The present application relates to the field of chip design technology, and in particular to a three-dimensional metal isolation wiring structure and wiring method for preventing crosstalk. Background Art

[0002] Signal integrity (SI) is an important concept in chip design, which considers the quality of signals during transmission. Factors that affect signal integrity include driving capability, line length, crosstalk, etc. In actual design, some high-speed, high-precision analog signals often need to be transmitted between some IPs. In order to ensure that these transmitted signals have good signal integrity, in addition to the design considerations of the IP itself, higher requirements are also required for the port interconnection lines between IPs, such as making the resistance-capacitance (RC) as small as possible to prevent crosstalk between signal lines. Among them, mutual crosstalk between signal lines will cause noise and burrs, which poses a greater threat to signal integrity. Therefore, how to reduce crosstalk is an issue worth exploring.

[0003] When two signal lines are close to each other, crosstalk will occur. Figure 1 As shown in the figure, there is a coupling capacitance C (Coupling capacitance) between the two signal lines. The closer the signal lines are, the larger the capacitance value is. When the aggressor line undergoes a low-level to high-level transition (0-1), the coupling capacitance is charged, and then the coupling capacitance causes a high-level glitch to appear on the victim line. If the victim line is undergoing a high-level to low-level transition (1-0) at this time, the victim line needs to discharge the coupling capacitance, which causes the two signal lines to interfere with each other and increases the level transition time (Transition time). This crosstalk will affect the signal integrity.

[0004] In chip back-end design, in order to avoid crosstalk, the spacing between signal lines can usually be increased during routing, or buffers can be inserted between longer signal lines. However, for the transmission of high-speed and high-precision analog signals, increasing the distance between signal lines sometimes cannot avoid crosstalk, and the required distance is difficult to control. Inserting a buffer unit introduces additional circuits, which increases the delay of the unit, which is not worth the loss. Summary of the invention

[0005] The present application provides a three-dimensional metal isolation wiring structure and wiring method for preventing crosstalk, which can prevent the occurrence of crosstalk in all directions and effectively ensure the integrity of high-speed and high-precision analog signals.

[0006] In a first aspect, an embodiment of the present application provides a three-dimensional metal isolation wiring structure for crosstalk prevention, comprising a first metal line, a second metal line, a third metal line, and a signal transmission line for transmitting a high-speed analog signal;

[0007] The first metal wire and the second metal wire are respectively arranged on the left and right sides of the signal transmission line;

[0008] The third metal line is arranged directly below the signal transmission line;

[0009] The first metal line, the second metal line and the third metal line are all grounded.

[0010] Furthermore, the third metal line is arranged in a metal layer next to the metal layer where the signal transmission line is located.

[0011] Furthermore, the width of the third metal line is consistent with the width of the signal transmission line.

[0012] Furthermore, the length of the first metal line, the length of the second metal line, and the length of the third metal line are consistent with the length of the signal transmission line.

[0013] Furthermore, the width of the first metal line and the width of the second metal line are obtained according to a process design rule description file.

[0014] Furthermore, the spacing between the first metal line, the second metal line and the signal transmission line is obtained according to the manufacturing process, the width of the signal transmission line, and the length of the signal transmission line.

[0015] In a second aspect, an embodiment of the present application provides a three-dimensional metal isolation wiring method for preventing crosstalk, which is applied to the three-dimensional metal isolation wiring structure for preventing crosstalk in any of the above embodiments, including:

[0016] Acquire a signal transmission line for transmitting high-speed analog signals;

[0017] Disposing a first metal wire and a second metal wire on the left and right sides of the signal transmission line respectively;

[0018] deploying a third metal line directly below the signal transmission line;

[0019] The first metal line, the second metal line, and the third metal line are all grounded.

[0020] Furthermore, the method also includes:

[0021] Get the width of the signal transmission line;

[0022] A third metal line having the same width as that of the signal transmission line is disposed directly below the signal transmission line.

[0023] Furthermore, the method also includes: obtaining the length of the signal transmission line; and respectively disposing a first metal wire and a second metal wire having the same length as the length of the signal transmission line on the left and right sides of the signal transmission line.

[0024] Furthermore, the method also includes:

[0025] The widths of the first metal line and the second metal line are obtained according to the process design rule description file.

[0026] In summary, compared with the prior art, the technical solution provided in the embodiment of the present application has at least the following beneficial effects:

[0027] An embodiment of the present application provides a three-dimensional metal isolation wiring structure for preventing crosstalk, in which grounded metal wires are deployed on the left side, right side and directly below the signal transmission line that transmits high-speed analog signals. The three-dimensional surround metal isolation structure composed of metal wires with zero potential can prevent the occurrence of crosstalk in all directions, thereby effectively ensuring the integrity of high-speed and high-precision analog signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of crosstalk between signal lines provided for an exemplary embodiment of the present application.

[0029] Figure 2 A schematic diagram of capacitance between metal layers provided for an exemplary embodiment of the present application.

[0030] Figure 3 A schematic diagram of a three-dimensional metal isolation wiring structure for crosstalk prevention provided by an exemplary embodiment of the present application.

[0031] Figure 4 A flowchart of a three-dimensional metal isolation wiring method for preventing crosstalk is provided for an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0033] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0034] In actual chips, parasitic capacitance exists between the same layer of metal and between different layers of metal. There is coupling capacitance between the same layer of metal, and there is surface capacitance between different layers of metal. Figure 2As shown. Among them, parasitic capacitance: coupling capacitance: Cc = e*T / S; surface capacitance: Cs = e*W / H. Factors that determine the capacitance value: metal line width: W; metal line thickness: T; spacing between metal lines on the same layer: S; thickness of dielectric materials between different layers: H; dielectric constant: e. Crosstalk may come from signal lines on the same layer or from metal lines on different layers. Therefore, for signal lines that need to be protected, these two sources of crosstalk should be avoided at the same time.

[0035] Therefore, see Figure 3 An embodiment of the present application provides a three-dimensional metal isolation wiring structure for preventing crosstalk, including a first metal line, a second metal line, a third metal line and a signal transmission line for transmitting high-speed analog signals.

[0036] The first metal wire and the second metal wire are respectively arranged on the left and right sides of the signal transmission line.

[0037] The third metal line is arranged directly below the signal transmission line.

[0038] The first metal line, the second metal line and the third metal line are all grounded.

[0039] Specifically, Figure 3 The metal line n in the figure is a signal transmission line for transmitting high-speed analog signals between two IPs, that is, a signal line that needs to be protected. The metal line a and the metal line b are the first metal line and the second metal line respectively, and the metal line c is the third metal line.

[0040] according to Figure 3 The given wiring structure completely isolates the signal transmission line to be protected from other signal lines by adding three-dimensional surround metal isolation, and the metal line used for isolation is connected to 0 potential. At this time, the parasitic capacitance of the protected signal transmission line is completely converted into ground capacitance, and the level conversion of other signal lines no longer interferes with the protected signal transmission line, thereby well ensuring the integrity of the analog signal in the signal transmission line.

[0041] In some embodiments, the third metal line is disposed in a metal layer next to the metal layer where the signal transmission line is located.

[0042] The first metal line and the second metal line are used to isolate interference of signal lines on the left and right sides of the same layer as the signal transmission line, and the third metal line is used to isolate interference of the signal line on the lower layer of the signal transmission line.

[0043] Specifically, assuming that the signal transmission line is the Mth metal layer in the chip, the third metal line is the M-1th layer. The upper metal layer of the signal transmission line does not need to lay out an additional metal line. In fact, if a similar signal line is to be placed above the signal transmission line, the signal line will also have isolation metal lines added on three sides. The upper metal layer of the signal transmission line is still isolation metal and will not be directly adjacent to the signal transmission line. What needs to be avoided is the interference between signal lines used to transmit analog signals, while metal lines connected to fixed potentials, such as power lines and ground lines, will not interfere with the signal lines because their potentials do not flip.

[0044] In some embodiments, the width of the third metal line is consistent with the width of the signal transmission line.

[0045] Specifically, it can be understood that the shape of the third metal line is the projection of the signal transmission line on the next metal layer, so except for the thickness, the width and length of the third metal line are completely consistent with the signal transmission line.

[0046] In some embodiments, the thickness of the first metal line, the thickness of the second metal line and the thickness of the signal transmission line are consistent.

[0047] Because the first metal wire, the second metal wire and the signal transmission wire are on the same metal layer, and in chip manufacturing, the thickness of the metal wires in the same layer is the same, which is related to the etching process, so the thickness of the metal wires is also the same.

[0048] In some embodiments, the length of the first metal line, the length of the second metal line, and the length of the third metal line are consistent with the length of the signal transmission line. Specifically, the length of the first metal line and the second metal line needs to be equal to the length of the signal transmission line, because it is to always provide isolation between signal lines on the same layer for the signal transmission line.

[0049] In some embodiments, the width of the first metal line and the width of the second metal line are obtained according to the process design rule description file. The spacing between the first metal line, the second metal line and the signal transmission line is obtained according to the manufacturing process, the width of the signal transmission line, and the length of the signal transmission line.

[0050] Specifically, the width of the first metal line and the second metal line is set to the minimum width of the metal layer, which is described in the process design rule description file. Because only the minimum width of the isolation metal is needed to achieve isolation between signal lines on the same layer, and the minimum width can save wiring resources. The first metal line. The spacing between the second metal line and the signal transmission line adopts the minimum spacing between metals specified by the process. The minimum spacing is determined by different processes, metal line widths, and parallel running line lengths. The process manufacturer will provide relevant design rule description files, and the minimum spacing can be set according to the requirements in the description files.

[0051] In some embodiments, the first metal line, the second metal line, and the third metal line are made of copper or aluminum.

[0052] Specifically, the material of metal wires and signal transmission lines is determined by the chip manufacturing process, usually copper, and the punching material is tungsten. Older processes use lower-cost aluminum.

[0053] See also Figure 4 Another embodiment of the present application provides a three-dimensional metal isolation wiring method for preventing crosstalk, which is applied to the three-dimensional metal isolation wiring structure for preventing crosstalk in any of the above embodiments, including:

[0054] Step S1, obtaining a signal transmission line for transmitting a high-speed analog signal.

[0055] Step S2, disposing a first metal wire and a second metal wire on the left and right sides of the signal transmission line respectively.

[0056] Step S3, deploying a third metal wire directly below the signal transmission line.

[0057] Step S4, grounding the first metal wire, the second metal wire and the third metal wire.

[0058] In some embodiments, the method further comprises:

[0059] Gets the width of the signal transmission line.

[0060] A third metal line having the same width as that of the signal transmission line is disposed directly below the signal transmission line.

[0061] Wherein, a third metal line corresponding to the signal transmission line may be disposed on a metal layer below the signal transmission line.

[0062] In some embodiments, the method further includes: obtaining the length of the signal transmission line; and deploying a first metal wire and a second metal wire having the same length as the length of the signal transmission line on the left and right sides of the signal transmission line, respectively.

[0063] In some embodiments, the method further comprises:

[0064] The widths of the first metal line and the second metal line are obtained according to the process design rule description file.

[0065] In some embodiments, the method further includes: obtaining a spacing between the first metal line, the second metal line, and the signal transmission line according to a manufacturing process, a width of the signal transmission line, and a length of the signal transmission line.

[0066] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A three-dimensional metal isolation wiring structure for crosstalk prevention, characterized in that: comprising a first metal line, a second metal line, a third metal line and a signal transmission line for transmitting a high-speed analog signal; The first metal line and the second metal line are respectively arranged on the left and right sides of the signal transmission line; The third metal line is arranged directly below the signal transmission line; the third metal line is arranged in a metal layer below the metal layer where the signal transmission line is located; the width of the third metal line is consistent with the width of the signal transmission line; The first metal line, the second metal line and the third metal line are all grounded.

2. The three-dimensional metal isolation wiring structure for crosstalk prevention according to claim 1, characterized in that: The length of the first metal line, the length of the second metal line, and the length of the third metal line are consistent with the length of the signal transmission line.

3. The anti-crosstalk three-dimensional metal isolation wiring structure according to claim 1, characterized in that: The width of the first metal line and the width of the second metal line are obtained according to a process design rule description file.

4. The anti-crosstalk three-dimensional metal isolation wiring structure according to claim 1, characterized in that: The spacing between the first metal line, the second metal line and the signal transmission line is obtained according to the manufacturing process, the width of the signal transmission line, and the length of the signal transmission line.

5. A three-dimensional metal isolation wiring method for preventing crosstalk, characterized in that: A three-dimensional metal isolation wiring structure for crosstalk prevention as claimed in any one of claims 1 to 4, comprising: Acquire a signal transmission line for transmitting high-speed analog signals; Disposing a first metal wire and a second metal wire on the left and right sides of the signal transmission line respectively; A third metal line is disposed directly below the signal transmission line; the third metal line is disposed in a metal layer below the metal layer where the signal transmission line is located; and the width of the third metal line is consistent with the width of the signal transmission line; The first metal line, the second metal line, and the third metal line are all grounded.

6. The anti-crosstalk three-dimensional metal isolation wiring method according to claim 5, characterized in that: Also includes: Obtaining the length of the signal transmission line; The first metal wire and the second metal wire having the same length as that of the signal transmission line are respectively disposed on the left and right sides of the signal transmission line.

7. The anti-crosstalk three-dimensional metal isolation wiring method according to claim 5, characterized in that: Also includes: The widths of the first metal line and the second metal line are obtained according to a process design rule description file.

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