Ball grid array package structure and PCB board ensuring impedance continuity

Abstract

The utility model discloses a kind of ball grid array packaging structure and PCB of guaranteeing impedance continuity, by the asymmetric spacing of control signal unit and two side ground unit, so that signal unit is offset to one side ground unit, the trace channel of the other side of signal unit is widened, the trace channel of widened not only can double trace, but also can be with thicker line width, so that the characteristic impedance of differential line is consistent on signal transmission path, significantly reduce signal reflection and waveform distortion risk, especially suitable for high-frequency, high-speed signal transmission scene, can ensure signal integrity.

Description

Technical Field

[0001] This utility model relates to the field of circuit board design technology, and more specifically, to a ball grid array packaging structure and PCB board that ensures impedance continuity. Background Technology

[0002] Ball Grid Array (BGA) packaging technology has been widely used in the electronics industry due to its advantages such as high density and high performance. When designing BGA-packaged chips, the pin pitch is typically 0.8mm, 0.9mm, or 1.0mm, with 0.9mm or 1.0mm pin pitch being common examples.

[0003] In BGA packaged PCB design, via-in-pad technology is often used. This technology places vias directly on the BGA pads, which helps reduce the space occupied by wiring and increase assembly density.

[0004] In conventional designs, for BGA packaged chips with a pin pitch of 0.9mm, the trace channel width is less than 20mil when using a pad-in-hole design. When using the NECK pattern with a trace width and spacing of W / S = 4mil / 4mil, it is difficult to meet the relevant requirements and effective impedance control is virtually impossible. For BGA packaged chips with a pin pitch of 1.0mm, the trace channel width using a conventional pad-in-hole design is less than 22mil, and the maximum supported trace width and spacing is W / S = 4mil / 4mil. When dealing with differential lines with impedance requirements below 80 ohms, impedance continuity cannot be guaranteed.

[0005] In conventional designs, differential traces are routed within the BGA area. To maintain impedance continuity, differential traces are typically run as single lines, with the trace width increased to half the target impedance. Differential signals are routed around ground vias as much as possible, and if there is still space, they are placed close to the ground vias and away from other differential vias. This utilizes the ground vias to create a shielding effect, reducing the risk of crosstalk with other differential vias. After the single-line fan-out of the BGA, the traces are then routed in a differential coupling configuration. However, this routing method involves multiple layers, which is disadvantageous for boards with limited thickness or cost constraints. If it is not possible to route them in a similar manner... Figure 1The routing shown here ignores the impedance effect for boards with layer and cost constraints; impedance is not controlled in the BGA area. However, for high-speed signals, impedance continuity is a crucial factor affecting signal quality. In high-speed signal transmission scenarios, impedance control is essential to ensure signal integrity and reliability. Impedance discontinuities or mismatches can lead to signal reflection, attenuation, crosstalk, and other problems, affecting signal quality and transmission efficiency, and potentially degrading the overall performance of the circuit board. Utility Model Content

[0006] To overcome the shortcomings of the prior art, this utility model provides a ball grid array packaging structure that ensures impedance continuity, so as to solve the problem of poor impedance continuity caused by insufficient trace space.

[0007] The technical solution of this utility model is as follows: a ball grid array packaging structure that ensures impedance continuity, comprising:

[0008] The BGA package area is formed on the PCB substrate. The BGA package area is provided with multiple ground units and multiple signal units arranged alternately along the X-axis.

[0009] Each signal unit has a ground unit on a first side in the X-axis direction, and the center distance between the two is a first distance; the signal unit has a ground unit on a second side in the X-axis direction, and the center distance between the two is a second distance, and a trace channel is formed between the signal unit and the ground unit located on the second side of the signal unit, wherein the first distance is smaller than the second distance.

[0010] Furthermore, the ground unit includes at least two return ground vias linearly arranged along the Y-axis, and the signal unit includes at least two differential signal vias linearly arranged along the Y-axis.

[0011] Furthermore, the diameter of the pad of the return ground hole is 0.4mm~0.5mm.

[0012] Furthermore, the pad diameter of the differential signal hole is 0.4mm~0.5mm.

[0013] Furthermore, the diameter of the differential signal aperture is 6 mil.

[0014] Furthermore, the diameter of the differential signal aperture is 8 mil.

[0015] Furthermore, the diameter of the differential signal aperture is 10 mil.

[0016] In addition, this utility model also provides a PCB board, including a PCB substrate body, on which the above-mentioned ball grid array packaging structure is disposed.

[0017] The advantages of this utility model based on the above solution are as follows:

[0018] This invention provides a ball grid array packaging structure that ensures impedance continuity. By controlling the asymmetrical spacing between the signal unit and the ground units on both sides, the signal unit is offset towards one side of the ground unit, and the trace channel on the other side of the signal unit becomes wider. The wider trace channel can not only support two traces, but also allow for traces with thicker line widths. This ensures that the characteristic impedance of the differential lines remains consistent along the signal transmission path, significantly reducing the risk of signal reflection and waveform distortion. It is especially suitable for high-frequency and high-speed signal transmission scenarios and can ensure signal integrity.

[0019] This invention provides a ball grid array packaging structure that ensures impedance continuity. By shifting the signal unit to one side, the width of the trace channel on the other side of the signal unit is increased, allowing two parallel traces to be arranged. The dual-line mode forms a symmetrical structure through tight coupling, thereby reducing the sensitivity to external radiation and interference and reducing crosstalk. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a BGA fan-out on a single line and then routed in a differential coupling manner.

[0022] Figure 2 This is a schematic diagram of the wiring of the ball grid array packaging structure in an embodiment of this utility model.

[0023] In the diagram, 1 is the BGA package area; 2 is the ground cell; 21 is the return ground via; 3 is the signal cell; and 31 is the differential signal via. Detailed Implementation

[0024] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments.

[0025] To better understand this utility model, the following description, in conjunction with the accompanying drawings and embodiments, will further illustrate the present utility model:

[0026] In BGA packaged PCB design, via-in-pad technology is often used. This technology places vias directly on the BGA pads, which helps reduce the space occupied by wiring and increase assembly density.

[0027] In conventional designs, for BGA packaged chips with a pin pitch of 0.9mm, the trace channel width using a via design is often less than 20mil. When using the NECK pattern with a trace width and spacing of W / S = 4mil / 4mil, it is difficult to meet the relevant requirements, and effective impedance control is virtually impossible. For BGA packaged chips with a pin pitch of 1.0mm, the trace channel width using a conventional via design is often less than 22mil, and the maximum supported trace width and spacing is W / S = 4mil / 4mil. When dealing with differential lines with impedance requirements below 80 ohms, impedance continuity cannot be guaranteed.

[0028] In conventional designs, differential traces are routed within the BGA area. To maintain impedance continuity, differential traces are typically run as single lines, with the trace width increased to half the target impedance. Differential signals are routed around ground vias as much as possible, and if there is still space, they are placed close to the ground vias and away from other differential vias. This utilizes the ground vias to create a shielding effect, reducing the risk of crosstalk with other differential vias. After the single-line fan-out of the BGA, the traces are then routed in a differential coupling configuration. However, this routing method involves multiple layers, which is disadvantageous for boards with limited thickness or cost constraints. If it is not possible to route them in a similar manner... Figure 1 The routing shown will ignore the impedance effect for single boards with layer and cost constraints. Impedance is not controlled in the BGA area. However, for high-speed signals, impedance continuity is one of the important factors affecting signal quality.

[0029] Based on this, the present invention provides a ball grid array packaging structure that ensures impedance continuity, see [link to relevant documentation]. Figure 2 As shown, the ball grid array packaging structure includes a BGA packaging area 1, which is formed on the PCB substrate body. Multiple ground units 2 and multiple signal units 3 are arranged alternately along the X-axis direction in the BGA packaging area 1.

[0030] Specifically, each signal unit 3 has a ground unit 2 on the first side in the X-axis direction, and the center distance between the two is a first distance; the signal unit 3 has a ground unit 2 on the second side in the X-axis direction, and the center distance between the two is a second distance. A wiring channel is formed between the signal unit 3 and the ground unit 2 located on the second side of the signal unit 3, wherein the first distance is smaller than the second distance.

[0031] This utility model provides a ball grid array packaging structure that ensures impedance continuity. By controlling the asymmetrical spacing between the signal unit 3 and the ground units 2 on both sides, the signal unit 3 is offset towards one side of the ground unit 2, and the trace channel on the other side of the signal unit 3 becomes wider. The wider trace channel can not only support two traces, but also allow for traces with thicker line widths. This ensures that the characteristic impedance of the differential lines remains consistent along the signal transmission path, significantly reducing the risk of signal reflection and waveform distortion. It is especially suitable for high-frequency and high-speed signal transmission scenarios and can ensure signal integrity.

[0032] This utility model provides a ball grid array packaging structure that ensures impedance continuity. By shifting the signal unit 3 to one side, the width of the trace channel on the other side of the signal unit 3 is increased, allowing two parallel traces to be arranged. The dual-line mode forms a symmetrical structure through tight coupling, thereby reducing the sensitivity to external radiation and external interference and reducing crosstalk.

[0033] In this embodiment, the ground unit 2 includes at least two return ground vias 21 arranged linearly along the Y-axis, and the signal unit 3 includes at least two differential signal vias 31 arranged linearly along the Y-axis. The Y-axis and X-axis are perpendicular to each other.

[0034] In this embodiment, the pad diameter of the return ground via 21 is 0.4mm~0.5mm.

[0035] In this embodiment, the pad diameter of the differential signal hole 31 is 0.4mm~0.5mm.

[0036] In this embodiment, the diameter of the differential signal aperture 31 is 6 mil; in another embodiment, the diameter of the differential signal aperture 31 is 8 mil; and in yet another embodiment, the diameter of the differential signal aperture 31 is 10 mil.

[0037] It should be noted that the diameter of the differential signal hole 31 of the ball grid array packaging structure that ensures impedance continuity provided by this utility model is not limited to the 6mil, 8mil and 10mil listed above. Those skilled in the art can set the aperture of the differential signal hole 31 according to actual production needs and process requirements.

[0038] It is worth mentioning that the ball grid array package structure that ensures impedance continuity provided by this utility model embodiment can achieve NECK pattern routing with line width and line spacing of W / S=5mil / 5mil for 0.9mm BGA packages; and NECK pattern routing with line width and line spacing of W / S=6mil / 6mil for 1.0mm BGA packages; thus meeting the requirements of different impedances.

[0039] It should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product is usually placed in during use, or the orientation or positional relationship that is commonly understood by those skilled in the art, or the orientation or positional relationship that the product is usually placed in during use. It is only for the purpose of facilitating the description of this application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0040] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

[0041] The present utility model patent has been described above with reference to the accompanying drawings. Obviously, the implementation of the present utility model patent is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present utility model patent, or the direct application of the inventive concept and technical solution of the present utility model patent to other occasions without modification, are all within the protection scope of the present utility model.

Claims

1. A ball grid array packaging structure that ensures impedance continuity, characterized in that, include: A BGA package area (1) formed on the PCB substrate is provided with multiple ground units (2) and multiple signal units (3) arranged alternately along the X-axis. Each signal unit (3) has a ground unit (2) on a first side in the X-axis direction, and the center distance between the two is a first distance; the signal unit (3) has a ground unit (2) on a second side in the X-axis direction, and the center distance between the two is a second distance; a wiring channel is formed between the signal unit (3) and the ground unit (2) located on the second side of the signal unit (3), wherein the first distance is smaller than the second distance.

2. The ball grid array packaging structure for ensuring impedance continuity as described in claim 1, characterized in that: The ground unit (2) includes at least two return ground vias (21) arranged linearly along the Y-axis, and the signal unit (3) includes at least two differential signal vias (31) arranged linearly along the Y-axis.

3. The ball grid array packaging structure for ensuring impedance continuity as described in claim 2, characterized in that: The pad diameter of the return ground via (21) is 0.4mm~0.5mm.

4. The ball grid array packaging structure for ensuring impedance continuity as described in claim 2, characterized in that: The pad diameter of the differential signal hole (31) is 0.4mm~0.5mm.

5. The ball grid array packaging structure for ensuring impedance continuity as described in claim 2, characterized in that: The diameter of the differential signal aperture (31) is 6 mil.

6. The ball grid array packaging structure for ensuring impedance continuity as described in claim 2, characterized in that: The diameter of the differential signal aperture (31) is 8 mil.

7. The ball grid array packaging structure for ensuring impedance continuity as described in claim 2, characterized in that: The diameter of the differential signal aperture (31) is 10 mil.

8. A PCB board, characterized in that, It includes a PCB substrate body, on which a ball grid array packaging structure as described in any one of claims 1 to 7 is disposed.

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