Wiring board, package for housing electronic component, and electronic module

Abstract

Provided is a wiring board comprising a first insulating substrate and a signal conductor pair. The signal conductor pair has a first signal conductor and a second signal conductor. The first signal conductor has a first bent portion for which the distance from the second signal conductor changes, and a first straight line portion that is directly connected to the first end side of the first bent portion. The second signal conductor has a second bent portion for which the distance from the first signal conductor changes, and a second straight portion directly connected to the second end side of the second bent portion. The first straight line portion and the second straight line portion are positioned parallel to each other. When viewed from a third direction orthogonal to both the first straight line portion and the second straight line portion, at least a portion of the first straight line portion and at least a portion of the second straight line portion overlap.

Description

Wiring board, package for storing electronic components, and electronic module

[0001] The present disclosure relates to a wiring board, an electronic component storage package, and an electronic module.

[0002] Conventionally, wiring boards for transmitting high-frequency signals sometimes use differential wiring, which has superior high-frequency transmission characteristics compared to ordinary wiring.

[0003] When providing differential wiring from one side of a wiring board to the other opposing side, there are cases where the differential wiring cannot be simply linear due to design considerations, etc. For example, in the wiring board disclosed in Patent Document 1, one end and the other end of the differential wiring are positioned offset in direction Y, resulting in the existence of non-linear portions in the differential wiring.

[0004] Japanese Patent Application Laid-Open No. 2021-108359

[0005] Wiring boards such as those described above, which have non-linear portions in the differential wiring, tend to have poorer high-frequency transmission characteristics than simple linear differential wiring due to effects such as noise generation caused by signal phase shifts, and there is room for improvement.

[0006] An object of the present disclosure is to provide a wiring board, an electronic component storage package, and an electronic module with improved high-frequency transmission characteristics.

[0007] (1) One aspect of a wiring board according to the present disclosure includes: a first insulating base having a first end surface and a second end surface facing the first end surface in a first direction; and a signal conductor pair located on the first insulating base from the first end surface side to the second end surface side, the signal conductor pair having a first signal conductor and a second signal conductor; a first end of the signal conductor pair located on the first end surface side of the first insulating base and a second end of the signal conductor pair located on the second end surface side of the first insulating base are shifted in a second direction intersecting the first direction; the first signal conductor has a first bent portion whose distance from the second signal conductor changes and a first straight portion directly connected to the first end side of the first bent portion; the second signal conductor has a second bent portion whose distance from the first signal conductor changes and a second straight portion directly connected to the second end side of the second bent portion; the first straight portion and the second straight portion are positioned parallel to each other; When viewed from a third direction perpendicular to both the first straight line portion and the second straight line portion, at least a portion of the first straight line portion and at least a portion of the second straight line portion overlap with each other.

[0008] (2) One aspect of the wiring board according to the present disclosure is the wiring board according to (1) above, wherein the entire length of the first signal conductor and the entire length of the second signal conductor are equal.

[0009] (3) One aspect of the wiring board according to the present disclosure is the wiring board of (1) or (2) above, wherein a portion of the first straight line portion that overlaps with the second straight line portion when viewed from the third direction is defined as a first section portion, a portion of the second straight line portion that overlaps with the first straight line portion when viewed from the third direction is defined as a second section portion, an end of the first section portion on the first end side is defined as a first point, and an end of the second section portion on the first end side is defined as a second point, and the length from the first end of the first signal conductor to the first point is equal to the length from the first end of the second signal conductor to the second point.

[0010] (4) One aspect of the wiring board according to the present disclosure is the wiring board of any of (1) to (3) above, wherein when the end of the first section portion on the second end side is defined as a third point and the end of the second section portion on the second end side is defined as a fourth point, the length from the second end of the first signal conductor to the third point is equal to the length from the second end of the second signal conductor to the fourth point.

[0011] (5) One aspect of the wiring board according to the present disclosure is the wiring board of either (1) or (2) above, wherein when a portion of the first straight portion that overlaps with the second straight portion when viewed from the third direction is defined as a first section, and a portion of the second straight portion that overlaps with the first straight portion when viewed from the third direction is defined as a second section, the first section is longer than the first bent portion, and the second section is longer than the second bent portion.

[0012] (6) One aspect of the wiring board according to the present disclosure is the wiring board of (3) or (4) above, wherein the first section is longer than the first bent portion, and the second section is longer than the second bent portion.

[0013] (7) One aspect of the wiring board according to the present disclosure is the wiring board of any one of (1) to (6) above, wherein the first bent portion has a first arc portion that is convex in a direction away from the second signal conductor, and the second bent portion has a second arc portion that is convex in a direction away from the first signal conductor.

[0014] (8) One aspect of the wiring board according to the present disclosure is the wiring board of (7) above, wherein the first bend portion has a third arc portion that is directly connected to the first arc portion and that is convex in a direction away from the second signal conductor, the second bend portion has a fourth arc portion that is directly connected to the second arc portion and that is convex in a direction away from the first signal conductor, the radii of curvature of the first arc portion and the third arc portion are equal, and the radii of curvature of the second arc portion and the fourth arc portion are equal.

[0015] (9) One aspect of the wiring board according to the present disclosure is the wiring board of any of (1) to (8) above, further comprising a first ground conductor and a second ground conductor located on the first insulating base, wherein the first ground conductor, the first signal conductor, the second signal conductor, and the second ground conductor are located side by side in this order, the first ground conductor is located away from the first signal conductor and has a portion that runs along the first signal conductor for at least a portion of the first signal conductor, and the second ground conductor is located away from the second signal conductor and has a portion that runs along the second signal conductor for at least a portion of the second signal conductor.

[0016] (10) One aspect of the wiring board according to the present disclosure is the wiring board of any of (1) to (9) above, further comprising a third ground conductor located on the first insulating base and between the first signal conductor and the second signal conductor, the third ground conductor being spaced apart from the first signal conductor and the second signal conductor, having a portion that runs along the first signal conductor for at least a portion of the first signal conductor, and having a portion that runs along the second signal conductor for at least a portion of the second signal conductor.

[0017] (11) One aspect of the wiring board according to the present disclosure is the wiring board according to any one of (1) to (10) above, further comprising a second insulating base located on the first insulating base.

[0018] (12) One aspect of the wiring board according to the present disclosure is the wiring board of (11) above, wherein when a portion of the first signal conductor closer to the first end than the first straight portion is defined as a first extension portion, and a portion of the second signal conductor closer to the first end than the second bend portion is defined as a second extension portion, in a planar view, the second insulating base overlaps at least a portion of the first extension portion and at least a portion of the second extension portion.

[0019] (13) One aspect of the wiring board according to the present disclosure is the wiring board of any of (1) to (12) above, further comprising an inner layer conductor located within the first insulating base, the inner layer conductor having a plurality of first openings and a plurality of second openings, wherein, in a planar view, the plurality of first openings overlap the first signal conductor and are positioned side by side along the first signal conductor, and the plurality of second openings overlap the second signal conductor and are positioned side by side along the second signal conductor.

[0020] (14) One aspect of a package for storing electronic components according to the present disclosure comprises a substrate, a frame body positioned on the substrate, and a wiring board according to any one of (1) to (13) above joined to the frame body.

[0021] (15) One aspect of the electronic module according to the present disclosure comprises: an electronic component storage package as described in (14) above; an electronic component located on the substrate and electrically connected to the signal conductor pair; and a lid located on the frame.

[0022] According to the present disclosure, the high-frequency transmission characteristics of wiring boards, electronic component housing packages, and electronic modules can be further improved.

[0023] 1 is a plan view of a wiring board. FIG. 1 is a plan view of a wiring board. FIG. 1 is a plan view of a wiring board. FIG. 2 is a plan view of a wiring board. FIG. 3 is a plan view of an inner layer conductor of a wiring board. FIG. 4 is a perspective view of a wiring board. FIG. 5 is a plan view of a wiring board used in a simulation. FIG. 6 is a plan view of a wiring board used in a simulation. FIG. 7 is a plan view of a wiring board used in a simulation. FIG. 8 is a graph showing simulation results. FIG. 9 is a graph showing simulation results. FIG. 10 is a perspective view of an electronic component storage package. FIG. 11 is an exploded perspective view of an electronic module.

[0024] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, for the sake of convenience, the drawings referred to below show only the main components necessary for explaining the embodiments in a simplified form. Therefore, the wiring board, electronic component storage package, and electronic module of the present disclosure may include optional components not shown in the drawings. Furthermore, the dimensions of the components in the drawings do not faithfully represent the dimensions, dimensional ratios, etc. of the actual components.

[0025] Furthermore, in the embodiments described below, expressions such as "constant," "orthogonal," "vertical," "parallel," or "linear" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "vertical," "parallel," or "linear" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0026] 1 and 2 are plan views of an embodiment of a wiring board according to the present disclosure, as viewed from above. The wiring board 1 of this embodiment includes a first insulating base 2 and a signal conductor pair 3.

[0027] The first insulating base 2 has a first end surface S1 and a second end surface S2 facing the first end surface S1. The direction in which the first end surface S1 and the second end surface S2 face each other is defined as a first direction X. The direction intersecting the first direction X is defined as a second direction Y. In the wiring substrate 1 of Figures 1 and 2, the first end surface S1 and the second end surface S2 face each other in parallel, and the first direction X and the second direction Y are perpendicular to each other.

[0028] The signal conductor pair 3 is located on the first insulating base 2 from the first end face S1 side to the second end face S2 side. The signal conductor pair 3 includes a first signal conductor 4 and a second signal conductor 5. The signal conductor pair 3 is a differential wiring that transmits a differential signal.

[0029] The end of the signal conductor pair 3 located on the first end face S1 side of the first insulating base 2 is referred to as the first end E1, and the end located on the second end face S2 side is referred to as the second end E2. The first end E1 and the second end E2 are offset in the second direction Y. The first signal conductor 4 and the second signal conductor 5 have substantially the same width and thickness. Here, "the first end E1 and the second end E2 are offset in the second direction Y" can be rephrased as "when a straight line parallel to the first direction X is drawn, the first end E1 and the second end E2 are not on the same straight line." The range of offset between the first end E1 and the second end E2 in the second direction Y is, for example, 1 mm or more and 20 mm or less.

[0030] The first signal conductor 4 has a first bent portion 4c and a first straight portion 4a. The first bent portion 4c is a bent portion whose distance from the second signal conductor 5 changes. The first straight portion 4a is a straight portion that is directly connected to the first end E1 side of the first bent portion 4c. Here, in the present disclosure, the bent shape is not limited to an arc shape as in the embodiment shown in FIGS. 1 and 2 , but may also be a broken line shape in which straight lines are connected to each other.

[0031] The second signal conductor 5 has a second bent portion 5c and a second straight portion 5a. The second bent portion 5c is a bent portion where the distance from the first signal conductor 4 changes. The second straight portion 5a is a straight portion that is directly connected to the second end E2 side of the second bent portion 5c.

[0032] The first linear portion 4a and the second linear portion 5a are positioned parallel to each other. A direction perpendicular to both the first linear portion 4a and the second linear portion 5a is defined as a third direction A.

[0033] At least a portion of the first linear portion 4 a and at least a portion of the second linear portion 5 a overlap when viewed from the third direction A. That is, the first linear portion 4 a has a portion that overlaps with the second linear portion 5 a when viewed from the third direction A. Furthermore, the second linear portion 5 a has a portion that overlaps with the first linear portion 4 a when viewed from the third direction A.

[0034] The portion of the first linear portion 4a that overlaps with the second linear portion 5a when viewed from the third direction A is defined as a first section 4b. The end of the first section 4b on the side of the first end E1 is defined as a first point P1. The end of the first section 4b on the side of the second end E2 is defined as a third point P3.

[0035] The portion of the second linear portion 5a that overlaps with the first linear portion 4a when viewed from the third direction A is defined as a second section 5b. The end of the second section 5b on the side of the first end E1 is defined as a second point P2. The end of the second section 5b on the side of the second end E2 is defined as a fourth point P4.

[0036] In differential wiring, the phases of signals traveling through adjacent portions of a pair of signal conductors in the transmission direction are inverted, allowing magnetic flux generated by the signals to cancel each other out and reducing the possibility of noise generation. However, if the phases of signals traveling through these portions deviate from the inverted state, the magnetic flux may not be sufficiently canceled out, potentially generating noise. When a nonlinear portion is present in differential wiring, the phases of signals traveling through adjacent portions of a pair of signal conductors in the transmission direction are likely to deviate from the inverted state, making noise more likely to occur. In contrast, the wiring board 1 of the present disclosure uses the first bend 4c and the second bend 5c to ensure that the signal phase remains inverted or close to inverted when it reaches the first section 4b and the second section 5b. In this state, the signal travels linearly through the first section 4b and the second section 5b, which are parallel to each other, reducing noise generation. This results in the wiring board 1 of the present disclosure having excellent high-frequency transmission characteristics. Furthermore, by providing the first bent portion 4c in the first signal conductor 4 and the second bent portion 5c in the second signal conductor 5, the lengths of the first signal conductor 4 and the second signal conductor 5 can be finely adjusted.

[0037] 1 and 2, the first end E1 does not contact the first end surface S1, and the second end E2 contacts the second end surface S2. Note that in the wiring board 1 of the present disclosure, the first end E1 may contact the first end surface S1, and the second end E2 may not contact the second end surface S2.

[0038] 1 and 2 , the total length of the first signal conductor 4 and the total length of the second signal conductor 5 are equal. That is, the length from the first end E1 to the second end E2 of the first signal conductor 4 and the length from the first end E1 to the second end E2 of the second signal conductor 5 are equal. This makes it easier for signals to be received in an inverted phase at the receiving end, resulting in better high-frequency transmission characteristics. Here, the length of the signal conductors (first signal conductor 4 and second signal conductor 5) in this disclosure refers to the length of the center line passing through the center of the signal conductor in the width direction.

[0039] 1 and 2, the length from the first end E1 to the first point P1 of the first signal conductor 4 is equal to the length from the first end E1 to the second point P2 of the second signal conductor 5. This allows the phase states of the mutually inverted differential signals in the first section 4b and the second section 5b to approach the same phase, improving high-frequency transmission characteristics.

[0040] 1 and 2, the length from the second end E2 to the third point P3 of the first signal conductor 4 is equal to the length from the second end E2 to the fourth point P4 of the second signal conductor 5. This allows the phase states of the mutually inverted differential signals in the first section 4b and the second section 5b to approach the same phase, improving high-frequency transmission characteristics.

[0041] 1 and 2, the first section 4b is longer than the first bend 4c, and the second section 5b is longer than the second bend 5c. This increases the distance over which a signal can be transmitted with its phase inverted or nearly so, further reducing noise generation.

[0042] In the embodiment shown in FIGS. 1 and 2 , the first bent portion 4c has a first arc portion 4d and a third arc portion 4e. The first arc portion 4d and the third arc portion 4e are both arc-shaped and convex in a direction away from the second signal conductor 5. The second bent portion 5c has a second arc portion 5d and a fourth arc portion 5e. The second arc portion 5d and the fourth arc portion 5e are both convex in a direction away from the first signal conductor 4. When the first bent portion 4c and the second bent portion 5c have arc portions, signal reflection is reduced and high-frequency transmission characteristics are improved compared to when the first bent portion 4c and the second bent portion 5c are polygonal. Furthermore, by having multiple arc portions in each bent portion, the length of the signal conductor can be adjusted while reducing the radius of curvature of each arc portion compared to when each bent portion has only one arc portion.

[0043] 1 and 2, the first arc portion 4d and the third arc portion 4e are directly connected to each other, and the second arc portion 5d and the fourth arc portion 5e are directly connected to each other.

[0044] The radius of curvature of each arc portion is, for example, 0.1 mm or more and 0.5 mm or less, but is not particularly limited. A radius of curvature of 0.1 mm or more reduces signal reflection and further improves high-frequency transmission characteristics. A radius of curvature of 0.5 mm or less can reduce the area occupied by the wiring, allowing for miniaturization of the wiring substrate 1. Here, the radius of curvature of the arc portion in this disclosure refers to the radius of curvature of the center line passing through the center of the arc portion in the width direction.

[0045] 1 and 2, the radius of curvature of the first arc portion 4d is equal to the radius of curvature of the third arc portion 4e, and the radius of curvature of the second arc portion 5d is equal to the radius of curvature of the fourth arc portion 5e.

[0046] 3 is a plan view of another embodiment of the wiring board 1 according to the present disclosure, viewed from above the wiring board 1. As shown in FIG. 3, the first bent portion 4c may have a first arc portion 4d but not a third arc portion 4e, and the second bent portion 5c may have a second arc portion 5d but not a fourth arc portion 5e. In the embodiment shown in FIG. 3, the radius of curvature of each arc portion may be 0.1 mm or more and 0.5 mm or less.

[0047] 1 and 2 , the wiring board 1 further includes a first ground conductor 6, a second ground conductor 7, and a third ground conductor 8 located on the first insulating base 2. The first ground conductor 6, the first signal conductor 4, the third ground conductor 8, the second signal conductor 5, and the second ground conductor 7 are located side by side in this order. The first ground conductor 6 is located away from the first signal conductor 4. The second ground conductor 7 is located away from the second signal conductor 5. The third ground conductor 8 is located away from the first signal conductor 4 and the second signal conductor 5. This strengthens the ground potential and reduces the occurrence of crosstalk noise.

[0048] 1 and 2 , the first ground conductor 6 may have a portion that extends along the first signal conductor 4 from the first end E1 to the second end E2 of the first signal conductor 4. The second ground conductor 7 may have a portion that extends along the second signal conductor 5 from the first end E1 to the second end E2 of the second signal conductor 5.

[0049] In the embodiment shown in Figures 1 and 2, the third ground conductor 8 has a portion that extends along the first signal conductor 4 only for a portion of the first signal conductor 4, and has a portion that extends along the second signal conductor 5 only for a portion of the second signal conductor 5.

[0050] FIG. 4 is a plan view of another embodiment of the wiring board 1 of the present disclosure, viewed from above. As shown in FIG. 4 , the wiring board 1 of the present disclosure may include a first ground conductor 6 and a second ground conductor 7, but may not include a third ground conductor 8. Even with this embodiment, the ground potential is strengthened and crosstalk noise is reduced compared to an embodiment that does not include the first ground conductor 6 and the second ground conductor 7. Furthermore, by adopting an embodiment that does not include the third ground conductor 8, the degree of coupling of signals transmitted between the first signal conductor 4 and the second signal conductor 5 can be increased compared to an embodiment that includes the third ground conductor 8, thereby reducing the possibility of crosstalk noise. Furthermore, by adopting an embodiment that does not include the third ground conductor 8, the distance between the first signal conductor 4 and the second signal conductor 5 can be reduced, thereby further miniaturizing the wiring board 1.

[0051] 5 is a plan view of another embodiment of the wiring board 1 of the present disclosure, viewed from above the wiring board 1. The wiring board 1 of the present disclosure may include a plurality of signal conductor pairs 3, as shown in FIG. 4. When the wiring board 1 includes a plurality of signal conductor pairs 3, it is not necessary for all of the signal conductor pairs 3 to be the signal conductor pairs 3 according to the present disclosure, and it is sufficient that at least one of the signal conductor pairs 3 is the signal conductor pair 3 according to the present disclosure.

[0052] The wiring board 1 of the present disclosure may further include an inner layer conductor 10 located inside the first insulating base 2. This shifts the resonance frequency to the higher frequency side, improving the high frequency transmission characteristics.

[0053] FIG. 6 is a plan view, viewed from above, of the inner layer conductor 10 included in the wiring board 1 according to the embodiment shown in FIG. 5 . The inner layer conductor 10 has a plurality of first openings 12 and a plurality of second openings 13. In plan view, the first openings 12 overlap the first signal conductors 4 and are aligned along the first signal conductors 4. In addition, the second openings 13 overlap the second signal conductors 5 and are aligned along the second signal conductors 5. This reduces impedance reduction while maintaining the resonant frequency at a high frequency. Note that "plan view" also includes "planar perspective." The shapes of the first openings 12 and the second openings 13 are not limited to being circular as shown in FIG. 6 , but may also be elliptical or polygonal. Furthermore, the shapes of the first openings 12 and the second openings 13 do not all need to be the same.

[0054] In one embodiment, the wiring board 1 may have multiple inner layer conductors 10. Here, each inner layer conductor 10 may have a first opening 12 and a second opening 13 of different shapes. In this case, the first opening 12 and the second opening 13 formed in each inner layer conductor 10 may overlap in a planar view. More specifically, the first opening 12 and the second opening 13 of the same shape may be formed in each inner layer conductor 10, and these first openings 12 and second openings 13 may overlap so as to match in a planar view. In other words, the multiple inner layer conductors 10 may not be partially formed in the areas overlapping with the first signal conductor 4 and the second signal conductor 5.

[0055] 5 and 6 represent ground via conductors 9. The ground via conductors 9 electrically connect the ground conductors (first ground conductor 6, second ground conductor 7, third ground conductor 8, etc.) located on the first insulating base 2 to the inner layer conductor 10.

[0056] The number and positions of the ground via conductors 9 are not particularly limited and may be determined appropriately depending on the shape of the signal conductor pair 3, etc.

[0057] 7 is a plan view of another embodiment of the wiring board 1 of the present disclosure, viewed from above the wiring board 1. As shown in Fig. 7, the wiring board 1 of the present disclosure may further include a second insulating base 11 located on the first insulating base 2. When the wiring board 1 is used in a package for storing electronic components, the second insulating base 11 can also serve as part of a frame.

[0058] As shown in FIG. 7, the second insulating base 11 may overlap at least a portion of the first extending portion 4f and at least a portion of the second extending portion 5f in plan view.

[0059] Fig. 8 is a perspective view of a portion of another embodiment of the wiring board 1 of the present disclosure. The wiring board 1 shown in Fig. 8 includes a first insulating base 2 and a second insulating base 11 located on the first insulating base 2. A portion of the second insulating base 11 is located on a portion of the first extending portion 4f and a portion of the second extending portion 5f.

[0060] 9A to 9D, the wiring board 1 of the present disclosure may further be connected to an external connection substrate 40. More specifically, the external connection substrate 40 may be electrically connected to the first extension portion 4 f and the second extension portion 5 f. The external connection substrate 40 may be, for example, a flexible printed circuit board (FPC), a printed circuit board (PCB), or the like.

[0061] The material of the first insulating substrate 2 is, for example, a ceramic sintered body such as an aluminum oxide sintered body, an aluminum nitride sintered body, a silicon carbide sintered body, a mullite sintered body, or a glass ceramic.

[0062] The material of the first insulating base 2 may be a resin such as an epoxy resin, polyimide, or liquid crystal polymer. By using, for example, polyimide or liquid crystal polymer as the material of the first insulating base 2, the wiring board 1 can also be used as a flexible printed circuit board (FPC) or a printed circuit board (PCB).

[0063] The material and forming method of the second insulating base 11 may be the same as or different from those of the first insulating base 2. The second insulating base 11 may be formed separately from the first insulating base 2, or may be formed integrally with the first insulating base 2. For example, the material of the first insulating base 2 may have a lower dielectric constant than the material of the second insulating base 11.

[0064] The materials for the first signal conductor 4, the second signal conductor 5, the first ground conductor 6, the second ground conductor 7, and the third ground conductor 8 may be, for example, metals such as tungsten, molybdenum, manganese, copper, gold, silver, or alloys thereof.

[0065] An example of a method for fabricating a wiring board 1 will be described. When the first insulating base 2 is made of an aluminum oxide sintered body and the first signal conductor 4, the second signal conductor 5, the first ground conductor 6, the second ground conductor 7, and the third ground conductor 8 are made of tungsten metallized layers, the wiring board can be fabricated, for example, as follows: First, the raw material powder for the first insulating base 2 is mixed with an organic solvent and an organic binder to form a slurry. The raw material powder for the first insulating base 2 mainly comprises aluminum oxide powder and a powder of silicon oxide or other sintering aid components. Next, the slurry is formed into a sheet using a forming method such as a doctor blade method or a lip coater method to form a ceramic green sheet. Furthermore, tungsten powder is mixed with an organic solvent and an organic binder to form a metal paste. The metal paste is then printed appropriately at a predetermined position on a ceramic green sheet using a method such as screen printing. If necessary, multiple ceramic green sheets are stacked to form a laminate. The laminate is then fired at a temperature of approximately 1300°C to 1600°C. Furthermore, the ground via conductors 9 can be formed by forming through-holes at predetermined positions in the ceramic green sheet prior to printing the metal paste, filling the through-holes with the same metal paste as described above, and firing the sheet together with the ceramic green sheet. A nickel film of approximately 1 to 10 μm and a gold film of approximately 0.1 to 3 μm may be formed, in that order, on the surfaces of the first signal conductor 4, the second signal conductor 5, the first ground conductor 6, the second ground conductor 7, and the third ground conductor 8. This protects the surfaces and improves their bondability with brazing filler metals, solder, etc.

[0066] Next, the results of a simulation showing the effects of the wiring board 1 of the present disclosure will be described with reference to FIGS. 9A to 9D and 10A to 10D.

[0067] 9A to 9D are plan views, viewed from above, of four wiring substrates with different wiring shapes used in the simulation. Each wiring substrate includes a first ground conductor 6, a first signal conductor 4, a third ground conductor 8, a second signal conductor 5, a second ground conductor 7, and a second insulating base 11 on a first insulating base 2.

[0068] The wiring board shown in FIG. 9A is a wiring board according to an embodiment of the present disclosure. The signal conductor pair consisting of a first signal conductor 4 and a second signal conductor 5 in the wiring board shown in FIG. 9A is referred to as Type 1. In the signal conductor pair of Type 1, the first signal conductor 4 has a first section 4b and a first bent portion 4c. The first bent portion 4c has a first arc portion 4d but does not have a third arc portion 4e. The second signal conductor 5 has a second section 5b and a second bent portion 5c. The second bent portion 5c has a second arc portion 5d but does not have a fourth arc portion 5e. The total length of the first signal conductor 4 and the total length of the second signal conductor 5 are equal. The length from the first end E1 to the first point P1 of the first signal conductor 4 and the length from the first end E1 to the second point P2 of the second signal conductor 5 are slightly different. Similarly, the length from the second end E2 to the third point P3 of the first signal conductor 4 and the length from the second end E2 to the fourth point P4 of the second signal conductor 5 are slightly different. The first section 4b is longer than the first bent section 4c, and the second section 5b is longer than the second bent section 5c.

[0069] The wiring board shown in Fig. 9B is a comparative example. A signal conductor pair consisting of a first signal conductor 4 and a second signal conductor 5 in the wiring board shown in Fig. 9B is referred to as Type 2. In the Type 2 signal conductor pair, the first signal conductor 4 does not have a first section 4b or a first bend 4c. Similarly, the second signal conductor 5 does not have a second section 5b or a second bend 5c. The total length of the first signal conductor 4 and the total length of the second signal conductor 5 are equal.

[0070] The wiring board shown in Figure 9C is a comparative example. A signal conductor pair consisting of a first signal conductor 4 and a second signal conductor 5 in the wiring board shown in Figure 9C is referred to as Type 3. In the Type 3 signal conductor pair, the first signal conductor 4 does not have a first section 4b or a first bend 4c. Similarly, the second signal conductor 5 does not have a second section 5b or a second bend 5c. The total length of the first signal conductor 4 and the total length of the second signal conductor 5 are equal. The Type 2 signal conductor pair and the Type 3 signal conductor pair have in common the fact that they are comparative examples, but have different shapes.

[0071] The wiring board shown in FIG. 9D is a wiring board of the present disclosure. The signal conductor pair consisting of a first signal conductor 4 and a second signal conductor 5 in the wiring board shown in FIG. 9D is referred to as Type 4. In the Type 4 signal conductor pair, the first signal conductor 4 has a first section 4b and a first bent portion 4c. The first bent portion 4c has a first arc portion 4d and a third arc portion 4e. The second signal conductor 5 has a second section 5b and a second bent portion 5c. The second bent portion 5c has a second arc portion 5d and a fourth arc portion 5e. The overall length of the first signal conductor 4 and the overall length of the second signal conductor 5 are equal. The length from the first end E1 to the first point P1 of the first signal conductor 4 and the length from the first end E1 to the second point P2 of the second signal conductor 5 are equal. Similarly, the length from the second end E2 to the third point P3 of the first signal conductor 4 is equal to the length from the second end E2 to the fourth point P4 of the second signal conductor 5. The first section 4b is longer than the first bent section 4c, and the second section 5b is longer than the second bent section 5c.

[0072] 10A and 10B are graphs showing simulation results. The vertical axis of the graph in FIG. 10A is SDC21 [dB]. SDC21 is the amount of mode conversion from differential mode to common mode between the first end E1 and the second end E2 of the first signal conductor 4 and the second signal conductor 5. The vertical axis of the graph in FIG. 10B is SCD21 [dB]. SCD21 is the amount of mode conversion from common mode to differential mode between the first end E1 and the second end E2 of the first signal conductor 4 and the second signal conductor 5. The larger the absolute value of SDC21 and SCD21, the smaller the amount of mode conversion. The horizontal axis of both the graphs in FIG. 10A and 10B is the frequency [GHz] of the transmission signal.

[0073] The simulation results shown in FIGS. 10A and 10B confirm that the Type 1 signal conductor pair has a smaller amount of mode conversion for both the SDC 21 and the SCD 21, and thus improved high-frequency transmission characteristics, compared to the Type 2 and Type 3 signal conductor pairs, which are comparative examples. Furthermore, the Type 4 signal conductor pair has an even smaller amount of mode conversion for both the SDC 21 and the SCD 21, and thus further improved high-frequency transmission characteristics. When bent portions (first bent portion 4c and second bent portion 5c) are provided in the differential wiring, a phase difference is likely to occur in the transmission signal between the first signal conductor 4 and the second signal conductor 5. This phase difference disrupts the balanced state of the differential wiring, increasing the amount of mode conversion. However, by adopting the configuration of the wiring board 1 of the present disclosure, the region where the balanced state is disrupted (in other words, the region where a phase difference occurs) can be reduced. Therefore, the configuration of the wiring board 1 of the present disclosure increases the possibility of reducing the amount of mode conversion compared to the comparative examples.

[0074] [Package for storing electronic components] The use of the wiring board of the present disclosure is not particularly limited, and the wiring board of the present disclosure can be used, for example, as a package for storing electronic components. The package for storing electronic components can store electronic components in an airtight seal.

[0075] 11 is a perspective view of an embodiment of an electronic component storage package according to the present disclosure. The electronic component storage package 20 of this embodiment includes a substrate 21, a frame 22, and the wiring board 1 of the present disclosure.

[0076] The substrate 21 is, for example, a rectangular plate-like member. The frame 22 is a frame-like member provided in a position surrounding an area where electronic components are mounted in a plan view. As shown in Fig. 11 , the frame 22 may have a light-transmitting portion 23 for transmitting and receiving light between the inside and outside of the electronic component storage package 20.

[0077] The substrate 21 and the frame 22 may be configured, for example, by stacking a plurality of insulating substrates. Examples of insulating substrates that can be used include ceramic sintered bodies such as aluminum oxide sintered bodies, aluminum nitride sintered bodies, silicon carbide sintered bodies, mullite sintered bodies, and glass ceramics. The material of the substrate 21 and the frame 22 may be metal. Examples of metals include copper, tungsten, molybdenum, iron, nickel, or cobalt, or alloys thereof. Specific examples of alloys include copper-tungsten alloy, copper-molybdenum alloy, and iron-nickel-cobalt alloy. The material of the substrate 21 and the material of the frame 22 may be the same or different.

[0078] 11 further includes a seal ring 24. The seal ring 24 is located on the upper surface of the frame 22. The seal ring 24 functions as a sealant when the lid 34 is used to hermetically seal the electronic component storage package 20 after the electronic component 32 is mounted in the electronic component storage package 20. The seal ring 24 may be formed, for example, by joining a frame-shaped metal plate containing an Fe—Ni alloy, an Fe—Ni—Co alloy, or the like to a frame formed from a conductive paste containing a high-melting-point metal such as tungsten or molybdenum using a brazing material or the like.

[0079] 12 is an exploded perspective view of an embodiment of an electronic module according to the present disclosure. The electronic module 30 of this embodiment includes the electronic component storage package 20 according to the present disclosure, an electronic component 32, and a lid 34.

[0080] The electronic component 32 is located on a mount member 31 provided on the substrate 21. The electronic component 32 is electrically connected to the signal conductor pair 3 by a connecting member such as a bonding wire 33. The electronic component 32 is an electronic component that inputs or outputs high-frequency signals (e.g., a frequency band of about 10 GHz or higher) related to optical communication. Specific examples of the electronic component 32 include a light-emitting element and a light-receiving element. However, these are merely examples, and the electronic component 32 is not limited to the above.

[0081] The lid 34 is positioned on the frame 22. The lid 34 is, for example, a plate-shaped member. The lid 34 may be any member that can reduce the intrusion of foreign matter such as moisture and fine particles into the interior (cavity) of the electronic module 30. The lid 34 is, for example, made of the same metal material as the seal ring 24, or the same ceramic material as the substrate 21 and frame 22, processed and formed into a plate shape.

[0082] As described above, the wiring board 1 according to the present disclosure includes a first insulating base 2 and a signal conductor pair 3. The first insulating base 2 has a first end face S1 and a second end face S2 that faces the first end face S1 in the first direction X. The signal conductor pair 3 is located on the first insulating base 2 from the first end face S1 to the second end face S2, and includes a first signal conductor 4 and a second signal conductor 5. The first end E1 of the signal conductor pair 3, located on the first end face S1 side of the first insulating base 2, and the second end E2 of the signal conductor pair 3, located on the second end face S2 side of the first insulating base 2, are offset in the second direction Y that intersects the first direction X. The first signal conductor 4 has a first bent portion 4c whose distance from the second signal conductor 5 changes, and a first straight portion 4a that is directly connected to the first end E1 side of the first bent portion 4c. The second signal conductor 5 has a second bent portion 5c whose distance from the first signal conductor 4 changes, and a second linear portion 5a directly connected to the second end E2 of the second bent portion 5c. The first linear portion 4a and the second linear portion 5a are positioned parallel to each other. When viewed from a third direction A perpendicular to both the first linear portion 4a and the second linear portion 5a, at least a portion of the first linear portion 4a and at least a portion of the second linear portion 5a overlap. The first bent portion 4c and the second bent portion 5c in the wiring board 1 of the present disclosure facilitate maintaining the phase of the signal in an inverted state or a state close to this when it reaches the first section 4b and the second section 5b. The signal travels linearly through the first section 4b and the second section 5b, which are parallel to each other, in this state, reducing noise generation. This results in the wiring board 1 of the present disclosure having excellent high-frequency transmission characteristics.

[0083] Furthermore, the total length of the first signal conductor 4 may be equal to the total length of the second signal conductor 5. This makes it easier for the signal to be received in an inverted phase at the receiving end, resulting in better high-frequency transmission characteristics.

[0084] Furthermore, when the portion of the first linear portion 4a that overlaps with the second linear portion 5a when viewed from the third direction A is defined as the first section 4b, the portion of the second linear portion 5a that overlaps with the first linear portion 4a when viewed from the third direction A is defined as the second section 5b, the end of the first section 4b on the side of the first end E1 is defined as the first point P1, and the end of the second section 5b on the side of the first end E1 is defined as the second point P2, the length from the first end E1 of the first signal conductor 4 to the first point P1 and the length from the first end E1 of the second signal conductor 5 to the second point P2 may be equal. This makes it easier for the phases of signals in the first section 4b and the second section 5b to be inverted, improving high-frequency transmission characteristics.

[0085] Furthermore, when the end of the first section 4b on the side of the second end E2 is defined as a third point P3 and the end of the second section 5b on the side of the second end E2 is defined as a fourth point P4, the length from the second end E2 of the first signal conductor 4 to the third point P3 may be equal to the length from the second end E2 of the second signal conductor 5 to the fourth point P4. This makes it easier for the phases of signals in the first section 4b and the second section 5b to be inverted, improving high-frequency transmission characteristics.

[0086] Furthermore, the first section 4b may be longer than the first bend 4c, and the second section 5b may be longer than the second bend 5c, thereby increasing the distance over which a signal is transmitted with its phase inverted or nearly so, and further reducing noise generation.

[0087] Furthermore, the first bent portion 4c may have a first arc portion 4d that is convex in a direction away from the second signal conductor 5, and the second bent portion 5c may have a second arc portion 5d that is convex in a direction away from the first signal conductor 4. By having the first bent portion 4c and the second bent portion 5c have arc portions in this way, signal reflection is reduced and high-frequency transmission characteristics are improved.

[0088] Furthermore, the first bent portion 4c has a third arc portion 4e that is directly connected to the first arc portion 4d and that is convex in a direction away from the second signal conductor 5, and the second bent portion 5c has a fourth arc portion 5e that is directly connected to the second arc portion 5d and that is convex in a direction away from the first signal conductor 4, and the radius of curvature of the first arc portion 4d and the third arc portion 4e may be equal, and the radius of curvature of the second arc portion 5d and the fourth arc portion 5e may be equal. By having multiple arc portions in each bent portion, the length of the signal conductor can be adjusted while reducing the radius of curvature of each arc portion compared to when each bent portion has only one arc portion.

[0089] The wiring board 1 may further include a first ground conductor 6 and a second ground conductor 7 located on the first insulating base 2, the first ground conductor 6, the first signal conductor 4, the second signal conductor 5, and the second ground conductor 7 being located side by side in this order, the first ground conductor 6 being located apart from the first signal conductor 4 and having a portion that runs along the first signal conductor 4 for at least a portion of the first signal conductor 4, and the second ground conductor 7 being located apart from the second signal conductor 5 and having a portion that runs along the second signal conductor 5 for at least a portion of the second signal conductor 5. This strengthens the ground potential and reduces the occurrence of crosstalk noise.

[0090] The wiring board 1 may further include a third ground conductor 8 located on the first insulating base 2 and between the first signal conductor 4 and the second signal conductor 5, and the third ground conductor 8 may be located with a gap between it and the first signal conductor 4 and the second signal conductor 5, and may have a portion that runs along the first signal conductor 4 for at least a portion of the first signal conductor 4, and may have a portion that runs along the second signal conductor 5 for at least a portion of the second signal conductor 5. This strengthens the ground potential and reduces the occurrence of crosstalk noise.

[0091] Moreover, the wiring board 1 may further include a second insulating base 11 located on the first insulating base 2. When the wiring board 1 is used in an electronic component storage package 20, the second insulating base 11 can also serve as part of the frame.

[0092] Furthermore, when the portion of the first signal conductor 4 closer to the first end E1 than the first straight portion 4a is defined as the first extension portion 4f, and the portion of the second signal conductor 5 closer to the first end E1 than the second bend portion 5c is defined as the second extension portion 5f, the second insulating base 11 may overlap with at least a portion of the first extension portion 4f and at least a portion of the second extension portion 5f in a planar view.

[0093] The first insulating base 2 further includes an inner layer conductor 10 located within the first insulating base 2, the inner layer conductor 10 having a plurality of first openings 12 and a plurality of second openings 13, and in plan view, the plurality of first openings 12 may overlap the first signal conductor 4 and be positioned side by side along the first signal conductor 4, and the plurality of second openings 13 may overlap the second signal conductor 5 and be positioned side by side along the second signal conductor 5. This reduces the decrease in impedance while maintaining the resonant frequency on the high frequency side.

[0094] An electronic component storage package 20 according to the present disclosure includes a substrate 21, a frame 22 positioned on the substrate 21, and the above-described wiring board 1 bonded to the frame 22. An electronic module 30 according to the present disclosure includes the above-described electronic component storage package 20, an electronic component 32 positioned on the substrate 21 and electrically connected to the signal conductor pairs 3, and a lid 34 positioned on the frame 22. By including a wiring board 1 with reduced noise generation, the electronic component storage package 20 and electronic module 30 according to the present disclosure have good high-frequency transmission characteristics.

[0095] Although the embodiments of the present disclosure have been described above, the wiring board 1, the electronic component storage package 20, and the electronic module 30 of the present disclosure are not limited to the above-described embodiments.

[0096] For example, the total length of the first signal conductor 4 and the total length of the second signal conductor 5 do not have to be equal.

[0097] The length of the first signal conductor 4 from the first end E1 to the first point P1 and the length of the second signal conductor 5 from the first end E1 to the second point P2 do not have to be equal.

[0098] The length from the second end E2 to the third point P3 of the first signal conductor 4 and the length from the second end E2 to the fourth point P4 of the second signal conductor 5 do not have to be equal.

[0099] The first section 4b may not be longer than the first bent section 4c, and the second section 5b may not be longer than the second bent section 5c.

[0100] The first bent portion 4c may not have the first arc portion 4d and the third arc portion 4e, and the second bent portion 5c may not have the second arc portion 5d and the fourth arc portion 5e. In this case, the first bent portion 4c and the second bent portion 5c are bent at, for example, a right angle.

[0101] The radius of curvature of the first arc portion 4d and the radius of curvature of the third arc portion 4e do not have to be equal, and the radius of curvature of the second arc portion 5d and the radius of curvature of the fourth arc portion 5e do not have to be equal.

[0102] The first ground conductor 6 may have a portion that extends along the first signal conductor 4 only for a portion of the first signal conductor 4. Furthermore, the wiring board 1 of the present disclosure does not necessarily have to include the first ground conductor 6.

[0103] The second ground conductor 7 may have a portion that extends along the second signal conductor 5 only for a portion of the second signal conductor 5. Furthermore, the wiring board 1 of the present disclosure does not necessarily have to include the second ground conductor 7.

[0104] The third ground conductor 8 may have a portion that extends along the first signal conductor 4 over the entire area from the first end E1 to the second end E2 of the first signal conductor 4, and may have a portion that extends along the second signal conductor 5 over the entire area from the first end E1 to the second end E2 of the second signal conductor 5. Furthermore, the wiring board 1 of the present disclosure does not necessarily have to include the third ground conductor 8.

[0105] The width in the third direction A of the third grounding conductor 8 located between the first section 4b and the second section 5b may be wider than the width in the third direction A of the first section 4b and the width in the third direction A of the second section 5b.

[0106] On the side of the second end face S2, the distance between the end of the third ground conductor 8 on the side of the second end face S2 and the second end face S2 may be greater than the distance between the second end E2 of the signal conductor pair 3 and the second end face S2.

[0107] The length of the first extension portion 4f and the length of the second extension portion 5f may be equal.

[0108] When the portion of the first signal conductor 4 closer to the second end E2 than the first bend portion 4c is defined as the third extension portion, and the portion of the second signal conductor 5 closer to the second end E2 than the second straight portion 5a is defined as the fourth extension portion, the second insulating base 11 may overlap with at least a portion of the third extension portion and at least a portion of the fourth extension portion in a planar view.

[0109] The third extension portion and the fourth extension portion may have the same length.

[0110] In the electronic component storage package 20 or the electronic module 30 , the entire wiring substrate 1 may be located inside (in a cavity of) the electronic component storage package 20 or the electronic module 30 .

[0111] In the electronic component storage package 20, the substrate 21, the frame 22, and the wiring board 1 may be separate members or may be an integrated member.

[0112] In addition, the details shown in the above embodiments can be modified as appropriate without departing from the spirit of the present disclosure. The scope of the present invention includes the scope of the invention described in the claims and its equivalents. Various combinations of the embodiments are not limited to the examples of the above embodiments. Furthermore, combinations of the embodiments with each other are also possible.

[0113] The present disclosure can be used for wiring boards, packages for housing electronic components, and electronic modules.

[0114] DESCRIPTION OF SYMBOLS 1 Wiring substrate 2 First insulating base 3 Signal conductor pair 4 First signal conductor 4a First straight portion 4b First section portion 4c First bend portion 4d First arc portion 4e Third arc portion 4f First extension portion 5 Second signal conductor 5a Second straight portion 5b Second section portion 5c Second bend portion 5d Second arc portion 5e Fourth arc portion 5f Second extension portion 6 First ground conductor 7 Second ground conductor 8 Third ground conductor 9 Ground via conductor 10 Inner layer conductor 11 Second insulating base 12 First opening 13 Second opening 20 Electronic component storage package 21 Substrate 22 Frame 23 Light-transmitting portion 24 Seal ring 30 Electronic module 31 Mounting member 32 Electronic component 33 Bonding wire 34 Lid 40 External connection substrate S1 First end surface S2 Second end surface E1 First end E2 Second end P1 First point P2 Second point P3 Third point P4 Fourth point X First direction Y Second direction A Third direction

Claims

1. A first insulating substrate having a first end face and a second end face facing the first end face in a first direction, The first insulating substrate comprises a pair of signal conductors, which are positioned on the first end face side to the second end face side and have a first signal conductor and a second signal conductor, The first end of the signal conductor pair located on the first end face side of the first insulating substrate and the second end of the signal conductor pair located on the second end face side of the first insulating substrate are offset in a second direction intersecting the first direction. The first signal conductor has a first bent portion whose distance from the second signal conductor changes, and a first straight portion which is directly connected to the first end of the first bent portion. The second signal conductor has a second bend in which the distance from the first signal conductor changes, and a second straight section that is directly connected to the second end of the second bend. The first straight section and the second straight section are located parallel to each other. When viewed from a third direction perpendicular to both the first and second straight sections, at least a portion of the first straight section and at least a portion of the second straight section overlap. Wiring board.

2. The total length of the first signal conductor and the total length of the second signal conductor are equal. The wiring board according to claim 1.

3. The portion of the first straight section that overlaps with the second straight section when viewed from the third direction is defined as the first section. The portion of the second straight section that overlaps with the first straight section when viewed from the third direction is defined as the second section. The end of the first section on the first end side is defined as the first point, When the end of the second section on the first end side is defined as the second point, The length from the first end of the first signal conductor to the first point and the length from the first end of the second signal conductor to the second point are equal. The wiring board according to claim 1.

4. The end of the first section on the second end side is designated as the third point. When the end of the second section on the second end side is designated as the fourth point, The length of the first signal conductor from the second end to the third point and the length of the second signal conductor from the second end to the fourth point are equal. The wiring board according to claim 3.

5. The portion of the first straight section that overlaps with the second straight section when viewed from the third direction is defined as the first section. When the portion of the second straight section that overlaps with the first straight section when viewed from the third direction is defined as the second section, The first section is longer than the first bent section. The second section is longer than the second bend. The wiring board according to claim 1.

6. The first section is longer than the first bent section. The second section is longer than the second bend. The wiring board according to claim 4.

7. The first bent portion has a first arc portion that is convex in the direction away from the second signal conductor, The second bent portion has a second arc portion that is convex in the direction away from the first signal conductor. The wiring board according to claim 1.

8. The first bent portion is directly connected to the first arc portion and has a third arc portion that is convex in the direction away from the second signal conductor. The second bent portion is directly connected to the second arc portion and has a fourth arc portion that is convex in the direction away from the first signal conductor. The radius of curvature of the first circular arc and the radius of curvature of the third circular arc are equal, The radius of curvature of the second arc and the radius of curvature of the fourth arc are equal. The wiring board according to claim 7.

9. The first insulating substrate further comprises a first grounding conductor and a second grounding conductor located on the first insulating substrate, The first ground conductor, the first signal conductor, the second signal conductor, and the second ground conductor are arranged in this order. The first grounding conductor is positioned at a distance from the first signal conductor and has a portion that runs along the first signal conductor with respect to at least a part of the first signal conductor. The second ground conductor is positioned at a distance from the second signal conductor and has a portion along the second signal conductor with respect to at least a part of the second signal conductor. The wiring board according to claim 1.

10. The present invention further comprises a third ground conductor located on the first insulating substrate and between the first signal conductor and the second signal conductor, The third ground conductor is positioned at a distance from the first signal conductor and the second signal conductor, and has a portion along the first signal conductor that is connected to at least a part of the first signal conductor, and a portion along the second signal conductor that is connected to at least a part of the second signal conductor. The wiring board according to claim 9.

11. The invention further comprises a second insulating substrate located on the first insulating substrate. The wiring board according to claim 1.

12. The portion of the first signal conductor closer to the first end than the first straight portion is designated as the first extension portion. When the portion of the second signal conductor closer to the first end than the second bent portion is designated as the second extended portion, In a plan view, the second insulating substrate overlaps with at least a portion of the first extended portion and at least a portion of the second extended portion. The wiring board according to claim 11.

13. The first insulating substrate further comprises an inner layer conductor located within the first insulating substrate, The inner layer conductor has a plurality of first openings and a plurality of second openings. In a plan view, the plurality of first openings overlap the first signal conductor and are positioned in a line along the first signal conductor. In a plan view, the plurality of second openings overlap the second signal conductor and are positioned aligned along the second signal conductor. The wiring board according to claim 1.

14. circuit board and A frame positioned on the aforementioned substrate, A wiring board according to any one of claims 1 to 13 is joined to the frame, Package for storing electronic components.

15. The electronic component housing package according to claim 14, An electronic component located on the substrate and electrically connected to the signal conductor pair, The frame comprises a lid positioned on the frame, Electronic module.