WO2021131192A1

WO2021131192A1 - Wiring structure

Info

Publication number: WO2021131192A1
Application number: PCT/JP2020/036178
Authority: WO
Inventors: 正人石▲崎▼; 久保　昇
Original assignee: Ｎｇｋエレクトロデバイス株式会社; 日本碍子株式会社
Priority date: 2019-12-26
Filing date: 2020-09-25
Publication date: 2021-07-01
Also published as: CN114424678B; JPWO2021131192A1; CN114424678A; JP7223170B2

Abstract

A wiring structure (100) is implemented using a ball grid array (90). A substrate (80) is made of a dielectric. A first differential line (131) is provided in the substrate (80), and includes a first signal line (11) and a second signal line (12). The second differential line (132) is provided in the substrate (80) and includes a third signal line (13) and a fourth signal line (14). A first pad (21) is connected to the first signal line (11). A second pad (22) is connected to the second signal line (12). A third pad (23) is adjacent to the second pad (22) with a ground region (20) therebetween, and is connected to the third signal line (13). A fourth pad is connected to the fourth signal line. The ground region (20) includes an interposed portion (20i) between the second pad (22) and the third pad (23), and a non-interposed portion (20n) away from the interposed portion (20i). The substrate (80) has a trench (TR).

Description

Wiring structure

The present invention relates to a wiring structure, and more particularly to a wiring structure to be mounted on a circuit board using a ball grid array (BGA).

BGA technology is one of the technologies for mounting wiring structures such as packages for electronic components. According to this technique, spherical conductive balls arranged in a grid pattern, typically solder balls, are used. For example, Japanese Patent Application Laid-Open No. 2008-283622 (Patent Document 1) discloses a multilayer dielectric substrate connected by BGA technology. The multilayer dielectric substrate has a pad for mounting solder balls and a columnar conductor connected to the pad and passing through the multilayer dielectric substrate.

Japanese Unexamined Patent Publication No. 2008-283622

In recent years, there has been a demand for higher density wiring structures. That is, miniaturization is required for the signal line to which the signal is provided and the ground portion to which the ground potential is provided in the wiring structure. If the conductive balls for mounting the wiring structure on the circuit board are also made smaller in response to this miniaturization, there is a possibility that the mounting reliability of the wiring structure by the conductive balls cannot be ensured. Specifically, first, if the size of the conductive ball is too small, the joint strength will decrease. Second, the conductive balls reduce the ability to relieve stress between the wiring structure and the circuit board. In particular, when the wiring structure is mainly made of ceramics and the circuit board is mainly made of resin, the difference in the coefficient of thermal expansion between the two is large, so that it is highly necessary to relax the thermal stress. Therefore, there is a limit to the miniaturization of the conductive ball as compared with the miniaturization in the wiring structure. Therefore, as the density increases, the size of the conductive ball tends to be relatively large compared to the cross section of the signal line in the wiring structure. Therefore, the distance between the conductive balls tends to be narrower than the distance between the signal line in the wiring structure and the signal line or the grounding portion adjacent to the signal line.

The wiring structure and the characteristic impedance of the circuit board on which it is mounted are usually almost the same. When the wiring spacing in the wiring structure is sufficient but the spacing between the conductive balls is too small, the characteristic impedance at the BGA junction composed of the conductive balls is higher than the characteristic impedance of the wiring structure and the circuit board. It will decrease locally. This local drop causes a mismatch in the characteristic impedance. The mismatch of the characteristic impedance adversely affects the transmission characteristics as the signal frequency becomes higher.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a wiring structure capable of obtaining good high frequency transmission characteristics while maintaining mounting reliability.

The wiring structure of one embodiment is to be mounted on a circuit board using a ball grid array. The wiring structure includes a substrate, a first differential line, a second differential line, a grounding area, a first pad, a second pad, a third pad, and a fourth pad. The substrate is made of a dielectric and has a facing surface that faces the circuit board. The first differential line is provided in the substrate, reaches the facing surface, and has a first signal line and a second signal line. The second differential line is provided in the substrate, reaches the facing surface, and has a third signal line and a fourth signal line. The grounding region is provided on the facing surface, and a grounding potential is applied. The first pad is provided on the facing surface and is connected to the first signal line. The second pad is provided on the facing surface and is connected to the second signal line. The third pad is provided on the facing surface, is adjacent to the second pad via the grounding region, and is connected to the third signal line. The fourth pad is provided on the facing surface and is connected to the fourth signal line. The ground contact area includes an intervening portion between the second pad and the third pad, and a non-intervening portion deviating from the intervening portion. The facing surfaces of the substrate are the first region between the first pad and the second pad, the second region between the second pad and the intervening portion, and each of the first pad and the second pad and the non-intervening portion. Includes a third region between and. The facing surface of the substrate has a trench in at least one of a first region, a second region, and a third region.

According to the above wiring structure, the characteristic impedance of the wiring increases near the trench. As a result, it is possible to suppress an adverse effect on the high-frequency transmission characteristic due to a local decrease in the characteristic impedance due to the proximity of the conductive balls to each other. Therefore, it is not necessary to make the size of the conductive balls excessively small in order to avoid the conductive balls from approaching each other, thereby maintaining the mounting reliability. From the above, good high-frequency transmission characteristics can be obtained while maintaining mounting reliability.

The objectives, features, aspects, and advantages of the present invention will be made clearer by the following detailed description and accompanying drawings.

It is sectional drawing which shows schematic the structure of the electronic device in Embodiment 1 of this invention. It is a circuit diagram of a part of the wiring structure in Embodiment 1 of this invention. It is a partial cross-sectional view corresponding to the broken line part III-III of FIG. It is a partial plan view which shows roughly the structure of the wiring structure in Embodiment 1 of this invention. It is a partial plan view which shows roughly the structure of the wiring structure in Embodiment 2 of this invention. It is a graph which shows the simulation result which shows the characteristic impedance as time domain reflection (TDR: Time Domain Reflectometry). It is a graph which shows the simulation result of the relationship between a reflection coefficient and a frequency. It is a graph which shows the simulation result of the relationship between a transmission coefficient and a frequency.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Embodiment 1>
FIG. 1 is a cross-sectional view schematically showing the configuration of the electronic device 900 according to the first embodiment. The electronic device 900 includes a package 100 (wiring structure), a BGA 90, a printed circuit board 200 (circuit board), an electronic component 300, an optical fiber 310, and a lid 400. The BGA 90 is for an electrical and mechanical connection between the package 100 and the printed circuit board 200 and includes solder balls 91 (conductive balls) arranged in a grid pattern.

As shown in the figure, the package 100 will be mounted on the printed circuit board 200 using the BGA 90. The package 100 has a substrate made of a dielectric (details will be described later), and this substrate has a bottom portion 101 and a frame portion 102. The bottom 101 has a mounting surface SM on which the electronic component 300 will be mounted. The frame portion 102 surrounds the space CV on the mounting surface SM. The frame portion 102 has a through hole portion 110 for passing the optical fiber 310. As a modification, a light transmitting portion may be provided instead of the through hole portion 110. The translucent portion is a window portion made of a translucent material.

In this embodiment, the electronic component 300 includes an integrated circuit (IC) 301 and an optical component 302 that are electrically connected to each other. The operating frequency of the IC 301 may be a high frequency, for example 55 GHz or higher. The optical component 302 is, for example, a photodiode. The optical fiber 310 is connected to the optical component 302 and extends out of the space CV through the through hole 110.

FIG. 2 is a circuit diagram of a partial configuration of the package 100 (FIG. 1). FIG. 3 is a partial cross-sectional view corresponding to the broken line portion III-III (FIG. 1). FIG. 4 is a partial plan view schematically showing the configuration of the package 100.

Package 100 has a substrate 80 made of a dielectric material. The substrate 80 is made of a dielectric, for example ceramics. The substrate 80 has a mounting surface SM and a facing surface SP. The facing surface SP faces the printed circuit board 200 via the BGA 90 when the package 100 is mounted on the printed circuit board 200. The electronic component 300 (FIG. 1) will be mounted on the mounting surface SM.

The package 100 has a differential line 131 (first differential line), a differential line 132 (second differential line), and a grounding portion 10 in the substrate 80, and these have a facing surface SP and a grounding portion 10. It has reached each of the mounting surfaces SM. The grounding portion 10 is for the electric shield of each of the differential line 131 and the differential line 132, and a ground potential (reference potential) is applied. The ground potential may be applied when the electronic device 900 is used. The differential line 131 has a signal line 11 (first signal line) and a signal line 12 (second signal line), and the differential line 132 has a signal line 13 (third signal line) and a signal line 14. It has (4th signal line).

The package 100 has a ground contact area 20, a pad 21 (first pad), a pad 22 (second pad), a pad 23 (third pad), and a pad 24 (fourth pad) on the facing surface SP of the substrate 80. ), Which are connected to the grounding portion 10, the signal line 11, the signal line 12, the signal line 13, and the signal line 14, respectively. The pad 23 is adjacent to the pad 22 via the ground contact area 20. A ground potential is applied to the ground region 20. The ground contact area 20 includes an intervening portion 20i between the pad 22 and the pad 23, and a non-intervening portion 20n separated from the intervening portion.

As shown in FIG. 4, the facing surface SP of the substrate 80 has a region R1 (first region) between the pad 21 and the pad 22 and a region R2 (first region) between the pad 22 and the intervening portion 20i. 2 regions) and a region R3 (third region) between each of the

pads

21 and 22 and the non-intervening portion 20n. The facing surface SP of the substrate 80 has a trench TR in at least one of the region R1, the region R2, and the region R3. The trench TR may be located at least in region R1. Further, the trench TR may be located at least in the region R2. Preferably, the trench TR is located at least in regions R1 and R2. More preferably, as shown in FIG. 4, the trench TR is located at least in region R1, region R2 and region R3.

In a planar layout (see FIG. 4), preferably, the portion of the trench TR adjacent to the pad 21 and the pad 22 is perpendicular to the edge ED and with respect to a virtual line passing through the midpoint between the pad 21 and the pad 22. It has line symmetry. More preferably, the portion of the trench TR adjacent to the pads 21 to 24 is perpendicular to the edge ED and has line symmetry with respect to the virtual line passing through the midpoint between the pad 22 and the pad 23.

The trench TR preferably has a depth of 100 μm or more and 300 μm or less. The dielectric constant of the space in the trench TR is lower than the dielectric constant of the substrate 80, typically about 1. Typically, the trench TR is filled with gas or is evacuated.

The trench TR does not have to reach the edge ED of the facing surface SP as shown in FIG. In that case, in the production of the substrate 80, it becomes easy to apply the construction method using a green sheet having punch holes corresponding to the trench TR. If the trench TR reaches the edge ED, the portion of the green sheet corresponding to the pad 21 is separated from the other surrounding portions, making it difficult to handle a single green sheet before laminating. When the trench is formed by, for example, laser processing after laminating the green sheet, the above problem does not occur even if the trench reaches the edge ED.

It is preferable that each of the pad 21, the pad 22, the pad 23 and the pad 24 is adjacent to the edge ED on the facing surface SP. Here, the fact that a certain pad is adjacent to the edge ED means that there is no other pad between the pad and the edge ED, as shown in FIG. Specifically, each of the pad 21, the pad 22, the pad 23, and the pad 24 is arranged on the outer periphery of the facing surface SP among the pads arranged in a grid pattern on the facing surface SP corresponding to the BGA 90. is there. Typically, the pads 21, pads 22, pads 23 and pads 24 are the pads closest to the edge ED of all the pads on the facing surface SP.

As shown in FIG. 2, the package 100 has a connection end 30, a connection end 31, a connection end 32, a connection end 33, and a connection end 34 on the mounting surface SM of the substrate 80. These may be connected to the grounding portion 10, the signal line 11, the signal line 12, the signal line 13, and the signal line 14, respectively. The connection end 30, the connection end 31, the connection end 32, the connection end 33, and the connection end 34 are used for electrical connection of the package 100 to the electronic component 300 (FIG. 1).

The printed circuit board 200 (FIG. 3) has a substrate 280 and a circuit pattern. The substrate 280 may be made of resin. In other words, the printed circuit board 200 may be a resin substrate. The circuit pattern includes, for example, a circuit pattern 220, a circuit pattern 221 and a circuit pattern 230, and a circuit pattern 231. Further, the printed circuit board 200 may have a via electrode 210 that connects the circuit pattern 220 and the circuit pattern 230 in the thickness direction, and a via electrode 211 that connects the circuit pattern 221 and the circuit pattern 231 in the thickness direction.

In the electronic device 900 (FIG. 1), as shown in FIG. 4, the solder balls 91 constituting the BGA 90 are arranged on each of the pad 21, the pad 22, the pad 23, the pad 24, and the ground contact area 20. Has been done. Therefore, when the electronic device 900 is manufactured, a package 100 in which the solder balls 91 constituting the BGA 90 are mounted is prepared on each of the pad 21, the pad 22, the pad 23, the pad 24, and the ground contact area 20. Ru. Then, the package 100 is mounted on the printed circuit board 200 using the BGA 90. For example, in the field of view shown in FIG. 3, the grounding region 20 and the circuit pattern 220 and the pad 21 and the circuit pattern 221 are joined by the solder balls 91.

The solder ball 91 is deformed at the time when it is mounted on the pad 21, the pad 22, the pad 23, the pad 24, the ground contact area 20, etc., and then when it is sandwiched between the package 100 and the printed circuit board 200. receive. As shown in FIG. 3, the solder ball 91 has a shape deformed from a spherical shape due to this deformation. When the diameter of a sphere having a volume equal to the volume of the solder ball 91 is defined as the ball diameter, the trench TR preferably has a depth of 1/3 or more of the ball diameter and less than or equal to the ball diameter. The ball diameter is preferably larger than 200 μm from the viewpoint of mounting reliability, and preferably smaller than 400 μm from the viewpoint of high density, for example, about 300 μm. The distance between the centers of the adjacent solder balls 91 is, for example, about 500 μm. The gap between adjacent solder balls (horizontal gap in FIG. 3) is usually smaller than the gap between adjacent pads (gap between

pads

20 and 21 in FIG. 3), and the balls as described above. When the diameter is 300 μm and the center-to-center distance is 500 μm, it is less than 200 μm.

According to this embodiment, the characteristic impedance of the wiring increases in the vicinity of the trench TR. As a result, it is possible to suppress an adverse effect on the high frequency transmission characteristics due to a local decrease in the characteristic impedance due to the proximity of the solder balls 91 to each other. Therefore, it is not necessary to make the size of the conductive balls 91 excessively small in order to avoid the solder balls 91 from approaching each other, thereby maintaining the mounting reliability. From the above, good high-frequency transmission characteristics can be obtained while maintaining mounting reliability.

Specifically, if the location where the characteristic impedance locally decreases due to the proximity of the solder balls 91 and the location where the characteristic impedance locally increases due to the trench TR are sufficiently close, unless the signal frequency is extremely high. , The characteristic impedance can be matched by substantially canceling these decrease and increase. Therefore, the distance between the solder ball 91 and the trench TR is preferably small, and this distance is, for example, less than or equal to the ball diameter.

The trench TR may be located at least in the area R1 (FIG. 4). As a result, the capacitive coupling between the wiring including the signal line 11 and the pad 21 and the wiring including the signal line 12 and the pad 22 becomes small. Therefore, the characteristic impedance of both wirings increases in the vicinity of the trench TR. Therefore, it is possible to suppress an adverse effect due to a local decrease in the characteristic impedance due to the proximity of the solder balls 91 on the pad 21 and the solder balls 91 on the pad 22. Therefore, the high frequency transmission characteristics of the wiring including the signal line 11 and the wiring including the signal line 12 can be improved. In other words, the high frequency transmission characteristics of the differential line 131 (FIG. 2) can be enhanced.

The trench TR may be located at least in the area R2 (FIG. 4). As a result, firstly, the capacitive coupling between the wiring including the signal line 12 and the pad 22 and the member including the grounding portion 10 and the grounding region 20 is reduced. Therefore, the characteristic impedance of the wiring increases in the vicinity of the trench TR. Therefore, it is possible to suppress an adverse effect due to a local decrease in the characteristic impedance due to the proximity of the solder balls 91 on the pad 22 and the solder balls 91 on the grounding region 20. Therefore, the high frequency transmission characteristics of the wiring can be improved. Secondly, the capacitive coupling between the wiring including the signal line 12 and the pad 22 and the wiring including the signal line 13 and the pad 23 becomes small. Therefore, crosstalk between the differential line 131 including the signal line 12 (FIG. 2) and the differential line 132 including the signal line 13 (FIG. 2) is suppressed.

Since the trench TR is located not only in the region R1 and the region R2 but also in the region R3, the room for impedance matching by the trench TR is further secured.

On the facing surface SP, as shown in FIG. 4, it is preferable that each of the pad 21, the pad 22, the pad 23 and the pad 24 is adjacent to the edge ED. As a result, the pads for the differential line 131 and the differential line 132 are arranged adjacent to the edge ED on the facing surface SP. Therefore, no other pad is arranged between the pad for these differential lines and the edge ED. Therefore, in the portion of the printed circuit board 200 (FIG. 3) near the edge ED, the wiring from the pad for the differential line can be arranged without being hindered by the wiring from these other pads.

The printed circuit board 200 is often a resin substrate, and in that case, when the substrate 80 of the package 100 is made of ceramics, the difference in the coefficient of thermal expansion between the printed circuit board 200 and the package 100 is large, and therefore thermal stress is likely to occur. According to this embodiment, since it is not necessary to make the solder balls 91 excessively small, this thermal stress can be sufficiently relaxed. This prevents the two from coming off due to thermal stress.

In the present embodiment, the solder ball 91 is used as the conductive ball of the BGA. This allows typical BGA techniques to be used.

When the depth of the trench TR is 1/3 or more of the ball diameter, it becomes easy to sufficiently secure the effect of reducing the capacitive coupling by the trench TR. When the depth of the trench TR is equal to or less than the ball diameter, it is possible to prevent the length of the portion of the wiring of the package 100 where the characteristic impedance is increased by the trench TR from becoming excessive. Therefore, it is possible to prevent the characteristic impedance from being increased even at a position far from the solder ball 91. Therefore, it is possible to prevent the mismatch of the characteristic impedance from being worsened due to the trench TR.

When the depth of the trench TR is 100 μm or more, it becomes easy to sufficiently secure the effect of reducing the capacitive coupling by the trench TR. When the depth of the trench TR is 300 μm or less, it is possible to prevent the length of the portion of the wiring in which the characteristic impedance is increased by the trench TR from becoming excessive. Therefore, it is possible to prevent the characteristic impedance from being increased even at a position far from the solder ball 91. Therefore, it is possible to prevent the mismatch of the characteristic impedance from being worsened due to the trench TR.

Since the base 80 has the frame portion 102 (FIG. 1), the package 100 can form a sealed space CV together with the lid 400. As a result, the electronic component 300 can be sealed in the space CV.

The through hole 110 of the frame 102 can be used to transmit light related to the optical component 302. Packages on which the optics 302 are mounted often require high frequency transmission. According to this embodiment, the characteristics of high frequency transmission can be enhanced.

In the present embodiment, the electronic component 300 (FIG. 1) mounted on the package 100 includes an optical component 302 to which the optical fiber 310 is connected. As a modification, the electronic component may not include an optical component and an optical fiber. Further, in the present embodiment, the package 100 has the frame portion 102, but as a modification, the wiring structure may not have the frame portion. Further, in the present embodiment, the solder ball 91, which is a typical conductive ball in the BGA connection, is used, but the conductive ball is not limited to the solder ball.

<Embodiment 2>
FIG. 5 is a partial plan view schematically showing the configuration of the package 100V (wiring structure) according to the second embodiment. In package 100V, the trench TR of the substrate 80 includes trenches TR1, trenches TR2 and trenches TR3 located in regions R1, regions R2 and regions R3, respectively. The trench TR of the package 100 (FIG. 4: Embodiment 1) corresponds to one configured by connecting the trench TR1, the trench TR2, and the trench TR3 to each other. On the other hand, the package 100V has trenches TR1, trench TR2 and trench TR3 separated from each other, as shown in FIG. As a modification, a form in which one of the trench TR1 and the trench TR2 is connected to the trench TR3 and the other is not connected may be used. Further, as another modification, only one or two of the trench TR1, the trench TR2, and the trench TR3 may be provided.

Since the configurations other than the above are almost the same as the configurations of the first embodiment described above, the same or corresponding elements are designated by the same reference numerals, and the description thereof will not be repeated.

The same effect as that of the first embodiment can be obtained by the present embodiment. Further, according to the present embodiment, since the trench TR1, the trench TR2 and the trench TR3 are separated from each other, a green sheet having punch holes corresponding to the trench TR1, the trench TR2 and the trench TR3 in the production of the substrate 80 is obtained. The method used can be easily applied.

<Simulation>
The simulation results of the influence of the structure of the trench TR (see FIG. 5) and the ball diameter of the solder balls on the high-frequency transmission characteristics will be described below with reference to FIGS. 6 to 8. In each figure, as a comparative example, the line E0a corresponds to the condition of the ball diameter of 300 μm and no trench, and the line E0b corresponds to the condition of the ball diameter of 200 μm and no trench. Further, as an example, the wire E2a corresponds to the condition that the ball diameter is 300 μm and the depths of the trenches TR1 and TR2 are 200 μm and there is no trench TR3, and the wire E2b has a ball diameter of 300 μm and the depths of the trenches TR1 and TR2 are 300 μm and the trench. Corresponding to the condition without TR3, the line E3a corresponds to the condition of the ball diameter of 300 μm and the depth of the trenches TR1 to TR3 of 200 μm, and the line E3b corresponds to the condition of the ball diameter of 300 μm and the depth of the trenches TR1 and TR2 of 300 μm and the depth of the trench TR3. It corresponds to the condition of 200 μm.

FIG. 6 is a graph showing a simulation result showing the characteristic impedance as a time domain reflection (TDR: Time Domain Reflectometry). The time axis of TDR can be regarded as the spatial axis, and in the figure, the range of about 50 to 65 ps corresponds to the position near BGA90. With reference to line E0a (ball diameter 300 μm and no trench) as a comparative example, a significant local drop in characteristic impedance is seen at approximately 50-65 ps, which leads to a significant mismatch in characteristic impedance. This inconsistency is mitigated by reducing the ball diameter from 300 μm to 200 μm with reference to line E0b (ball diameter 200 μm and no trench) as a comparative example. However, as described above, if the ball diameter is small, there is a concern that the mounting reliability may be lowered. On the other hand, according to the embodiment (line E2a, line E2b, line E3a and line E3b), the mismatch of the characteristic impedance is alleviated while using the ball diameter of 300 μm.

FIG. 7 is a graph showing the simulation results of the relationship between the reflection coefficient and the frequency. The comparative example line E0a (ball diameter 300 μm and no trench) has a higher reflectance in the range of approximately 20-60 GHz than any other example, which is unsuitable for transmission. Means a characteristic. With reference to line E0b (ball diameter 200 μm and no trench) as a comparative example, the reflectance coefficient is reduced by reducing the ball diameter from 300 μm to 200 μm. However, as described above, if the ball diameter is small, there is a concern that the mounting reliability may be lowered. On the other hand, according to Examples (Line E2a, Line E2b, Line E3a and Line E3b), the reflectance coefficient is reduced while using a ball diameter of 300 μm. It is considered that the reduction of the reflectance coefficient is due to the characteristic impedance being more matched in the vicinity of BGA90.

FIG. 8 is a graph showing the simulation results of the relationship between the transmission coefficient and the frequency. The wire E0a (ball diameter 300 μm and no trench) as a comparative example has a smaller transmission coefficient than any other example in the range of about 60 GHz or less, which is an unsuitable transmission characteristic. Means. With reference to line E0b (ball diameter 200 μm and no trench) as a comparative example, the transmission coefficient is increased by reducing the ball diameter from 300 μm to 200 μm. However, as described above, if the ball diameter is small, there is a concern that the mounting reliability may be lowered. On the other hand, according to Examples (Line E2a, Line E2b, Line E3a and Line E3b), the transmission coefficient is increased while using a ball diameter of 300 μm. The increase in the transmission coefficient is considered to be due to the reduction of signal reflection in the vicinity of BGA90.

Although the present invention has been described in detail, the above description is exemplary in all aspects and the invention is not limited thereto. It is understood that innumerable variations not illustrated can be assumed without departing from the scope of the present invention.

10: Grounding part 11: 1st signal line 12: 2nd signal line 13: 3rd signal line 14: 4th signal line 20: Grounding area 20i: Intervening part 20n: Non-intervening part 21: 1st pad 22: 2nd Pad 23: 3rd pad 24: 4th pad 30 to 34: Connection end 80: Base 90: BGA
91: Solder ball (conductive ball)
100:

Wiring structure

100, 100V: Package (wiring structure)
101: Bottom 102: Frame 110: Through hole 131: First differential line 132: Second differential line 200: Printed circuit board (circuit board)
210, 211: Via electrode 220, 211,230,231: Circuit pattern 280: Base 300: Electronic component 302: Optical component 310: Optical fiber 400: Lid 900: Electronic device CV: Spatial ED: Edge R1: First region R2: 2nd area R3: 3rd area SM: Mounting surface SP: Facing surface TR, TR1 to TR3: Trench

Claims

It is a wiring structure that will be mounted on a circuit board using a ball grid array.
A substrate made of a dielectric and having an opposing surface that faces the circuit board,
A first differential line provided in the substrate, reaching the opposite surface, and having a first signal line and a second signal line.
A second differential line provided in the substrate, reaching the opposite surface, and having a third signal line and a fourth signal line.
A grounding region provided on the facing surface to which a grounding potential is applied, and a grounding region.
A first pad provided on the facing surface and connected to the first signal line, and
A second pad provided on the facing surface and connected to the second signal line, and
A third pad provided on the facing surface, adjacent to the second pad via the grounding region, and connected to the third signal line,
A fourth pad provided on the facing surface and connected to the fourth signal line, and
With
The ground contact area includes an intervening portion between the second pad and the third pad, and a non-intervening portion deviating from the intervening portion.
The facing surfaces of the substrate include a first region between the first pad and the second pad, a second region between the second pad and the intervening portion, the first pad and the first pad. Includes a third region between each of the two pads and the non-intervening portion.
The facing surface of the substrate has a trench in at least one of the first region, the second region, and the third region.
Wiring structure.
The wiring structure according to claim 1, wherein the trench is located at least in the first region.
The wiring structure according to claim 1 or 2, wherein the trench is located at least in the second region.
The wiring structure according to claim 1, wherein the trench is located at least in the first region and the second region.
The wiring structure according to claim 1, wherein the trench is located at least in the first region, the second region, and the third region.
The facing surface has an edge, and each of the first pad, the second pad, the third pad, and the fourth pad is adjacent to the edge on the facing surface, claim 1. The wiring structure according to any one of 5 to 5.
The wiring structure according to any one of claims 1 to 6, wherein the substrate is made of ceramics.
Any of claims 1 to 7, further comprising conductive balls constituting the ball grid array on each of the first pad, the second pad, the third pad, the fourth pad, and the ground contact area. The wiring structure described in item 1.
The wiring structure according to claim 8, wherein the conductive ball is a solder ball.
8. When the diameter of a sphere having a volume equal to the volume of the conductive ball is defined as the ball diameter, the trench has a depth of 1/3 or more of the ball diameter and less than or equal to the ball diameter. Or the wiring structure according to 9.
The wiring structure according to any one of claims 1 to 10, wherein the trench has a depth of 100 μm or more and 300 μm or less.
The substrate according to any one of claims 1 to 11, wherein the substrate has a mounting surface on which at least one electronic component is to be mounted and a frame portion surrounding the space on the mounting surface. Wiring structure.
The wiring structure according to claim 12, wherein the at least one electronic component includes an optical component, and the frame portion has at least one of a through hole portion and a translucent portion.