CN116113136A

CN116113136A - Circuit board structure applied to mobile PCI Express module

Info

Publication number: CN116113136A
Application number: CN202111322942.8A
Authority: CN
Inventors: 詹涷璿; 黄敏伦; 陈忠信
Original assignee: Adlink Technology Inc
Current assignee: Adlink Technology Inc
Priority date: 2021-11-10
Filing date: 2021-11-10
Publication date: 2023-05-12

Abstract

The invention relates to a circuit board structure applied to a mobile PCI Express module, which accords with PCIe4.0 standard according to the stacking design, the size of a wire and the impedance control and the degree of signal attenuation. The circuit board structure comprises a top signal layer, a bottom signal layer, a power layer, a plurality of first insulating layers and a second insulating layer. The bottom signal layer and the top signal layer comprise a core board and conductive copper wires. The power layer is disposed between the top signal layer and the bottom signal layer. The first insulating layer is arranged between the top signal layer and the power layer, and between the bottom signal layer and the power layer. The second insulating layer is arranged between the power supply layer and the first insulating layer. The dielectric loss value of the first insulating layer and the second insulating layer is between 0.004 and 0.014, and the length of the conductive copper wire is between 500mil and 2500mil, so that the signal loss of the top signal layer and the bottom signal layer is less than 8dB.

Description

Circuit board structure applied to mobile PCI Express module

Technical Field

The present invention relates to a circuit board structure applied to a mobile PCI Express module, and more particularly, to a circuit board structure applied to a mobile PCI Express module and conforming to the PCIe4.0 specification of a graphics processor.

Background

Computers have become one of the indispensable communication equipments in daily life, and people can conduct data processing and data transmission through the computers. Along with the rapid development of computer technology, portable notebook computers are developed, which further brings practicability and convenience for life.

Notebook computers may include business, fashion, and multimedia applications. The business notebook computer comprises the characteristics of high mobility and long battery endurance time; fashion style notebook computers have an appearance that attracts consumers; the notebook computer of the multimedia application type combines strong graphics and multimedia processing capability and has a certain mobility.

Generally, a notebook computer includes a motherboard, and a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a mobile PCI Express module (MXM), and other electronic devices for processing data and signals are disposed on the motherboard. Currently, the mobile PCI Express module (MXM) for processing graphics data is only developed to 3.0 versions, and the data transmission and processing speed can reach 8GT/s and the bandwidth can reach 32GB/s. With the increasing technological days and the increasing standard of living, the demands for bandwidth, efficiency and speed of notebook computer for processing data are also increasing. Therefore, the electronic components of the notebook computer are required to be upgraded or replaced to meet the requirements of consumers. However, in the conventional circuit board structure of the PCI Express module, only data with a bandwidth of 32BG/s can be transmitted and processed, and when the circuit board structure processes data with a bandwidth of more than 32GB/s and the transmission speed is required to be more than 8.0GT/s, signal interference and signal loss of data transmission can be greatly increased, so that the signal transmission quality and transmission speed are reduced.

Therefore, there is a need to develop a new circuit board structure to solve the problems of the prior art.

Disclosure of Invention

Accordingly, the present invention is directed to a circuit board structure for a mobile PCI Express module, which can solve the problems of the prior art, effectively improve signal transmission quality and transmission speed, and reduce signal loss and crosstalk.

In order to achieve the above objective, the present invention discloses a circuit board structure applied to a mobile PCI Express module, which is used to conform to the pcie4.0 specification, and is characterized in that the circuit board structure applied to the mobile PCI Express module comprises:

a top signal layer;

a bottom signal layer located at the other side of the top signal layer, wherein the top signal layer and the bottom signal layer comprise a core board and a conductive copper wire, and the conductive copper wire is arranged on the surface of the core board to conduct signals;

at least one power layer disposed between the top signal layer and the bottom signal layer;

a plurality of first insulating layers disposed between the top signal layer and the power layer and between the bottom signal layer and the power layer; and

the second insulating layers are arranged between the power supply layer and the first insulating layers;

wherein, the length of the conductive copper wire is between 500mil and 2500mil, so that the signal loss of the mobile PCI Express module is less than 8dB.

The first ground layer is disposed between the top signal layer and the power layer and between the first insulating layers and the second insulating layers.

The second ground layer is disposed between the power layer and the bottom signal layer and between the first insulating layers and the second insulating layers.

The first insulating layer is respectively positioned among the top signal layer, the third grounding layer, the first middle signal layer and the first grounding layer.

The second intermediate signal layer and the fourth ground layer are arranged between the bottom signal layer and the second intermediate signal layer, and the fourth ground layer is arranged between the bottom signal layer and the second intermediate signal layer.

Wherein the top signal layer and the bottom signal layer comprise an impedance value, and the impedance value is between 76.5Ω and 93.5Ω.

Wherein, the conductive copper wire forms a plurality of arc-shaped wiring structures on the surface of the core plate.

Wherein, the conductive copper wire is arranged on the surface of the core board in a 10-degree wiring mode.

The material of the first insulating layers is epoxy resin composite material, and the epoxy resin composite material comprises at least one of TU-883 and TU-863+.

The thickness of the first insulating layers and the second insulating layers is between 0.05mm and 0.08 mm.

In summary, the circuit board structure applied to the mobile PCI Express module of the present invention can effectively reduce the signal loss of the signal layer and improve the signal transmission quality and transmission speed through the insulating layer containing the ultra-low loss material and the special multi-layer stack structure, so as to conform to the transmission specification of PCIe4.0 of the mobile PCI Express module. In addition, the signal layer of the circuit board structure applied to the mobile PCI Express module can also reduce signal loss and crosstalk through various wiring modes.

Drawings

FIG. 1 is a schematic diagram of a circuit board structure applied to a PCI Express module according to an embodiment of the invention.

FIG. 2 is a schematic diagram of a top signal layer according to an embodiment of the invention.

FIG. 3 is a schematic diagram showing signal loss of a circuit board structure applied to a PCI Express module according to an embodiment of the invention.

FIG. 4 is a schematic diagram showing signal loss of a circuit board structure applied to a PCI Express module according to an embodiment of the invention.

Detailed Description

In order that the advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments that are illustrated in the appended drawings. It should be noted that these embodiments are merely representative embodiments of the present invention, and the specific methods, devices, conditions, materials, etc. are not meant to limit the present invention or the corresponding embodiments. The devices are shown for expressing relative positions and are not drawn to actual scale.

In the description of the present specification, reference to the term "one embodiment," "another embodiment," or "a portion of an embodiment," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments. Furthermore, the indefinite articles "a" and "an" preceding an apparatus or element of the invention are not limited to the requirements of the number of apparatuses or elements (i.e. the number of occurrences). Thus, the use of "a" or "an" should be interpreted as including one or at least one, and the singular means or elements also include the plural unless the amount clearly indicates the singular.

The circuit board structure applied to the mobile PCI Express module can be used for conforming to the PCIe (PCI Express) 4.0 specification and can be applied to a bus interface of a graphics processor conforming to the PCIe4.0 specification.

Please refer to fig. 1 and 2. FIG. 1 is a schematic diagram of a circuit board structure 1 applied to a PCI Express module according to an embodiment of the invention. Fig. 2 is a schematic diagram showing a structure of the top signal layer 11 according to an embodiment of the invention. As shown in fig. 1, in the present embodiment, the circuit board structure 1 applied to the mobile PCI Express module includes a top signal layer 11, a bottom signal layer 12, a power layer 13, a plurality of first insulating layers 141 and a plurality of second insulating layers 142. The bottom signal layer 12 is disposed opposite to the top signal layer 11. The power layer 13 is disposed between the top signal layer 11 and the bottom signal layer 12. The first insulating layers 141 are disposed between the top signal layer 11 and the power layer 13 and between the bottom signal layer 12 and the power layer 13. The plurality of second insulating layers 142 are disposed between the power supply layer 13 and the plurality of first insulating layers 141.

In practice, the circuit board structure 1 applied to the mobile PCI Express module may be a multi-layer board structure, and the top signal layer 11 and the bottom signal layer 12 are respectively located at the outermost layers of the multi-layer board. The outer surfaces of the top signal layer 11 and the bottom signal layer 12 can be respectively provided with passive devices, integrated circuits, chips, etc.

As shown in fig. 2, the top signal layer 11 includes a core 111 and a plurality of conductive copper wires 112, and the conductive copper wires 112 are disposed on the surface of the core 111. In practice, the top signal layer 11 may be a copper-clad plate formed by hot pressing. The core board 111 may be an insulating substrate (e.g., paper substrate, fiberglass cloth substrate, synthetic fiber cloth substrate, nonwoven fabric substrate, composite substrate, etc.) composed of a high molecular synthetic resin and a reinforcing material, and the electronic component 5 may be disposed on the surface of the core board 111. Further, the surface of the core plate 111 may be covered with a copper foil layer and etched to form the conductive copper lines 112. The conductive copper wires 112 may be designed according to the positions and distributions of the electronic components 5 disposed on the core 111 and may connect the electronic components 5 to conduct the electronic components 5 and to conduct signals. In addition, the outer side of the top signal layer 11 may further include a Solder Mask (Solder Mask) to prevent the electronic component 5 from contacting the conductive copper wires 112 when soldered to the core 111.

The bottom signal layer 12 may also include the same core board, conductive copper wires and solder mask as the top signal layer 11, and the structure and function of the core board, conductive copper wires and solder mask are substantially the same as those described above, and will not be repeated here. In this embodiment, the lengths of the conductive copper lines of the top signal layer 11 and the bottom signal layer 12 are between 500mil and 2500 mil. It should be noted that the positions of the electronic components and the routing pattern of the conductive copper lines on the bottom signal layer 12 may be different from those on the top signal layer 11, and may be determined according to the design.

In this embodiment, the conductive copper wires 112 may form a plurality of arc-shaped wiring structures 1121 on the surface of the core 111. In practice, when the conductive copper wire 112 needs to turn the trace due to the design of the circuit or the electronic device 5, the arc-shaped trace structure 1121 can avoid the Acid angle phenomenon (Acid tracks) generated by the right-angle trace or the acute-angle trace, so as to reduce the impedance of the conductive copper wire 112 and further improve the signal transmission quality. In addition, the conductive copper wires 112 may be disposed on the surface of the core 111 in a 10-degree wiring manner. In practice, the conductive copper wires 112 with 10-degree wiring can effectively reduce the influence of the non-uniformity of the dielectric constant of the core 111 and the impedance of signal transmission, thereby improving the signal transmission quality and reducing the signal loss and the Crosstalk phenomenon (cross talk) between the conductive copper wires 112. In the present embodiment, the impedance values of the top signal layer 11 and the bottom signal layer 12 are between 76.5Ω and 93.5Ω, but the present invention is not limited thereto, and the impedance values of the top signal layer 11 and the bottom signal layer 12 may be determined according to design or requirements.

As shown in fig. 1, in the present embodiment, the power layer 13 is disposed between the top signal layer 11 and the bottom signal layer 12, and is used for providing power to the electronic components disposed on the top signal layer 11 and the bottom signal layer 12. In practice, when the electronic components applied to the circuit board structure 1 of the PCI Express module need to be driven by a plurality of different voltages or currents, the power layers 13 may be a multi-layer power plane structure, as shown in FIG. 1, the number of the power layers 13 is 4, but not limited thereto, and the number of the power layers may be determined according to the design. In another embodiment, the power layer may also be a single layer structure.

In this embodiment, the first insulating layer 141 is disposed between the top signal layer 11 and the power layer 13 and between the bottom signal layer 12 and the power layer 13. The second insulating layer 142 is disposed between the power supply layer 13 and the first insulating layers 141, and further, the second insulating layer 142 may be staggered with the power supply layers 13 (as shown in fig. 1). In practice, the first insulating layer 141 and the second insulating layer 142 are dielectric layers (i.e. semi-cured layers) and are respectively disposed between the top signal layer 11, the bottom signal layer 12 and the power layer 13 in a staggered manner to prevent short circuits between the signal layers and the power layer. The thickness of the first insulating layer 141 and the second insulating layer 142 may be between 0.05mm and 0.08mm, and the dielectric loss values (Dissipation Factor, df) of the first insulating layer 141 and the second insulating layer 142 may be between 0.004 and 0.014. As shown in fig. 1, the circuit board structure 1 applied to the mobile PCI Express module is arranged from top to bottom in the manner of a top signal layer 11, a first insulating layer 141, a power layer 13, a second insulating layer 142, a power layer 13, a first insulating layer 141 and a bottom signal layer 12. The material of the first insulating layer 141 and the second insulating layer 142 can be epoxy resin composite material (such as FR-4, FR-5, FR-6, CEM-1-CEM-5, etc.). Also, the materials of the first insulating layer 141 and the second insulating layer 142 may include a low-loss material or an ultra-low-loss material. In one embodiment, the material of first insulating layer 141 comprises TU-883 or TU863+, and the material of second insulating layer 142 comprises TU-865. That is, the first insulating layer 141 is a composite material of epoxy-bonded TU-883 or TU863+, and the second insulating layer 142 is a composite material of epoxy-bonded TU-865. Therefore, after the top signal layer 11, the bottom signal layer 12, the power layer 13, the first insulating layer 141 and the second insulating layer 142 are thermally pressed to form the circuit board structure 1 applied to the mobile PCI Express module, the first insulating layer 141 and the second insulating layer 142 can maintain the signal transmission quality of the top signal layer 11, the bottom signal layer 12 and the power layer 13 and reduce the signal loss.

It should be noted that, in practice, the material of the first insulating layer 141 is not limited to include the aforementioned TU-883 and TU863+, and the material of the second insulating layer 142 is not limited to include the aforementioned TU-865, and the first insulating layer 141 and the second insulating layer 142 may also include other low-loss materials or ultra-low-loss materials, which may also be determined according to design or requirements. The material of the second insulating layer 142 may be the same as that of the first insulating layer 141. Further, when the power layer 13 has a single-layer structure, the second insulating layers 142 may be disposed on opposite sides of the power layer 13, respectively.

In this embodiment, the circuit board structure 1 applied to the mobile PCI Express module further includes a first ground layer 151 and a second ground layer 152. The first ground layer 151 is disposed between the top signal layer 11 and the power layer 13 and between the first insulating layer 141 and the second insulating layer 142. The second ground layer 152 is disposed between the power layer 13 and the bottom signal layer 12 and between the first insulating layer 141 and the second insulating layer 142. As shown in fig. 1, the circuit board structure 1 applied to the mobile PCI Express module is arranged from top to bottom as a top signal layer 11, a first insulating layer 141, a first ground layer 151, a second insulating layer 142, a power layer 13, a second insulating layer 142, a second ground layer 152, a first insulating layer 141, and a bottom signal layer 12. In practice, the first ground layer 151 is used for grounding and separating the top signal layer 11 and the power layer 13, so as to prevent crosstalk between the top signal layer 11 and the power layer 13. In addition, the first ground layer 151 may also form a coupling capacitor with the adjacent power layer 13, so that not only the impedance of the power layer 13 and the first ground layer 151 can be reduced, but also the power layer 13 can obtain a wider filtering effect, and further the signal transmission quality and the signal transmission speed can be improved. Similarly, the second ground layer 152 is used for grounding and separating the bottom signal layer 12 and the power layer 13, and the second ground layer 152 can also form a coupling capacitor with the adjacent power layer 13 to prevent crosstalk between the bottom signal layer 12 and the power layer 13 and improve signal transmission quality and transmission speed. Therefore, the circuit board structure applied to the mobile PCI Express module can effectively reduce signal loss and improve signal transmission quality and transmission speed through the insulating layer containing the ultra-low loss material and a special multi-layer stacking mode so as to meet the specification of PCIe 4.0.

In this embodiment, the circuit board structure 1 applied to the mobile PCI Express module further includes a first intermediate signal layer 161 and a third ground layer 153. The first intermediate signal layer 161 and the third ground layer 153 are disposed between the top signal layer 11 and the first ground layer 151, and the third ground layer 153 is disposed between the top signal layer 11 and the first intermediate signal layer 161. The first insulating layer 141 is located between the top signal layer 11, the third ground layer 153, the first intermediate signal layer 161 and the first ground layer 151, respectively. Along with miniaturization of electronic products and high speed of data transmission, the circuit board comprises signal layers arranged inside the circuit board in addition to the outermost signal layers at two sides so as to improve the data transmission quantity and the data transmission speed. As shown in fig. 1, the circuit board structure 1 applied to the mobile PCI Express module is arranged between the top signal layer 11 and the power layer 13 as the top signal layer 11, the first insulating layer 141, the third ground layer 153, the first insulating layer 141, the first intermediate signal layer 161, the first insulating layer 141, the first ground layer 151, the second insulating layer 142 and the power layer 13. In practice, the first intermediate signal layer 161 may include the core and the conductive copper wires and is used for conducting signals, and the third ground layer 153 is used for grounding and separating the top signal layer 11 and the first intermediate signal layer 161, so as to prevent crosstalk between the top signal layer 11 and the first intermediate signal layer 161.

In addition, in the present embodiment, the circuit board structure 1 applied to the mobile PCI Express module further includes a second intermediate signal layer 162 and a fourth ground layer 154. The second intermediate signal layer 162 and the fourth ground layer 154 are disposed between the bottom signal layer 12 and the second ground layer 152, and the fourth ground layer 154 is disposed between the bottom signal layer 12 and the second intermediate signal layer 162. The first insulating layer 141 is disposed between the bottom signal layer 12, the fourth ground layer 154, the second intermediate signal layer 162 and the second ground layer 152, respectively. As shown in fig. 1, the circuit board structure 1 applied to the mobile PCI Express module is arranged between the power layer 13 and the bottom signal layer 12 as the power layer 13, the second insulating layer 142, the second ground layer 152, the first insulating layer 141, the second intermediate signal layer 162, the first insulating layer 141, the fourth ground layer 152, the first insulating layer 141 and the bottom signal layer 12. In practice, the second intermediate signal layer 162 may include the core and the conductive copper wires and is used for conducting signals, and the fourth ground layer 154 is used for grounding and separating the bottom signal layer 12 and the second intermediate signal layer 162, so as to prevent crosstalk between the bottom signal layer 12 and the second intermediate signal layer 162.

It should be noted that the number of the internal signal layers of the circuit board structure applied to the mobile PCI Express module is not limited to two (the first intermediate signal layer 161 and the second intermediate signal layer 162) in fig. 1, and in practice, the number of the internal signal layers of the circuit board structure applied to the mobile PCI Express module may be 1 or 3 or more.

Please refer to fig. 1, 3 and 4. FIG. 3 is a schematic diagram showing the signal loss of the circuit board structure 1 applied to the PCI Express module according to one embodiment of the invention. FIG. 4 is a schematic diagram showing the signal loss of the circuit board structure 1 applied to the PCI Express module according to one embodiment of the invention. As shown in fig. 3 and 4, the X-axis is the length value (in english) of the conductive copper wire, and the Y-axis is the signal loss value (dB). In a preferred embodiment, as shown in FIG. 3, when the material of the first insulating layer 141 is the ultra-low loss material TU-883, the material of the second insulating layer 142 is TU-865, the impedance values of the top signal layer 11 and the bottom signal layer 12 are 85 Ω, and the length of the conductive copper wires is 500 mil-2500 mil, the signal loss of the mobile PCI Express module (MXM) can be less than 8dB, and the signal loss of the circuit board structure 1 applied to the mobile PCI Express module can be less than 5dB. In practice, in the PCIe4.0 specification, the signal loss of the external/extrapolated graphics processing module is less than 8dB. Further, the loss generated by the electronic device in the package is about 3dB, that is, the signal loss of the circuit board structure applied to the mobile PCI Express module is less than 5dB. In a preferred embodiment, as shown in fig. 4, when the material of the first insulating layer 141 is the low-loss material TU-863+, the material of the second insulating layer 142 is TU-865, the impedance value of the top signal layer 11 and the bottom signal layer 12 is 85 Ω, and the length of the conductive copper wire is 500 mil-2500 mil, the signal loss of the circuit board structure 1 applied to the mobile PCI Express module can be less than 5dB. Therefore, the circuit board structure applied to the mobile PCI Express module can effectively reduce the signal loss value through the selection of the material of the insulating layer, the length of the conductive copper wire and the impedance value of the signal layer, so that the circuit board structure applied to the mobile PCI Express module can meet the transmission specification of PCIe 4.0.

From the foregoing detailed description of the preferred embodiments, it is intended to more clearly describe the nature and spirit of the invention, but not to limit the scope of the invention by the above disclosed preferred embodiments. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. The scope of the claimed invention should therefore be accorded the broadest interpretation based upon the foregoing description so as to encompass all such modifications and equivalent arrangements.

Claims

1. A circuit board structure for a mobile PCI Express module, for conforming to PCIe (PCI Express) 4.0.0 specification, comprising:

a top signal layer;

the dielectric loss values of the first insulating layers and the second insulating layers are between 0.004 and 0.014, and the length of the conductive copper wire is between 500mil and 2500mil, so that the signal loss of the mobile PCI express module is less than 8dB.

2. The circuit board structure of claim 1 further comprising a first ground layer disposed between the top signal layer and the power layer and between the first insulating layers and the second insulating layers.

3. The circuit board structure of claim 1 further comprising a second ground layer disposed between the power plane and the bottom signal plane and between the first insulating layers and the second insulating layers.

4. The circuit board structure of claim 2, further comprising a first intermediate signal layer and a third ground layer disposed between the top signal layer and the first ground layer, wherein the third ground layer is disposed between the top signal layer and the first intermediate signal layer, and wherein the first insulating layers are disposed between the top signal layer, the third ground layer, the first intermediate signal layer, and the first ground layer, respectively.

5. The circuit board structure of claim 3, further comprising a second intermediate signal layer and a fourth ground layer disposed between the bottom signal layer and the second ground layer, wherein the fourth ground layer is disposed between the bottom signal layer and the second intermediate signal layer, and the first insulating layers are disposed between the bottom signal layer, the fourth ground layer, the second intermediate signal layer, and the second ground layer, respectively.

6. The circuit board structure of claim 1, wherein the top signal layer and the bottom signal layer comprise an impedance value between 76.5 Ω and 93.5 Ω.

7. The circuit board structure of claim 1, wherein the conductive copper wires form a plurality of arc-shaped traces on the surface of the core board.

8. The circuit board structure of claim 1, wherein the conductive copper wires are disposed on the surface of the core board in a 10 degree wiring manner.

9. The circuit board structure of claim 1, wherein the first insulating layers are made of epoxy composite material, and the epoxy composite material comprises at least one of TU-883 and TU-863+.

10. The circuit board structure of claim 1, wherein the thickness of the first insulating layers and the second insulating layers is between 0.05mm and 0.08 mm.