Wiring board, package, and optical module

Abstract

A wiring board according to the present disclosure comprises: a first insulating substrate; a first ground conductor; and a first signal conductor. The first insulating substrate has: a first upper surface; a first side surface connected to the first upper surface; and a first notch cut out from the first upper surface to the first side surface. The first ground conductor includes: a first portion that is located on the first upper surface and that extends from a line overlapping the first side surface in plan view; and a second portion that is located in the first notch and that is connected to the first portion. The first signal conductor is located, on the first upper surface, side by side with the first ground conductor in a first direction. The first portion surrounds at least a portion of the first notch in plan view. On the line overlapping the first side surface in plan view, the distance between the center of the first ground conductor and the first signal conductor is shorter than the distance between the center of the first notch portion and the first signal conductor.

Description

Wiring board, package and optical module

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

[0002] Conventionally, a wiring board has been known that has a signal conductor, a castellation formed on a side surface, and a ground conductor formed from the side of the signal conductor into the castellation (see, for example, Patent Document 1).

[0003] JP 2012-222079 A

[0004] The wiring board of the present disclosure includes a first insulating base having a first top surface, a first side surface connected to the first top surface, and a first cutout portion cut out from the first top surface to the first side surface, a first ground conductor having a first portion located on the first top surface and extending from a line overlapping the first side surface in a plan view, and a second portion located within the first cutout portion and connecting to the first portion, and a first signal conductor located on the first top surface and aligned with the first ground conductor in a first direction. The first portion surrounds at least a portion of the first cutout portion in a plan view. On the line overlapping the first side surface in a plan view, the distance between the center of the first ground conductor and the first signal conductor is smaller than the distance between the center of the first cutout portion and the first signal conductor.

[0005] The package of the present disclosure includes a wiring board and a frame body joined to the wiring board.

[0006] The optical module of the present disclosure includes a package, an optical element mounted in the package, and a lid joined to the package.

[0007] 1A and 1B are plan views of wiring boards according to an embodiment of the present disclosure;

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, for the sake of convenience, the figures referred to below are simplified views of the main components necessary for explaining the embodiments. Therefore, embodiments of the present disclosure may include optional components not shown in the figures referred to. Furthermore, the figures do not necessarily faithfully represent the dimensional ratios of the actual components. For convenience, directions are defined using the Cartesian coordinate system XYZ. The positive side of the X direction is the right side, the positive side of the Y direction is the front side, and the positive side of the Z direction is the top side. In this disclosure, "planar view" refers to a view from the top side of the wiring board (the positive side of the Z direction) and includes planar perspective views.

[0009] In the following description, expressions such as "constant," "orthogonal," "vertical," "parallel," or "same" may be used. These expressions are not necessarily intended to strictly mean "constant," "orthogonal," "vertical," "parallel," or "same." In other words, these expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc. Numerical ranges expressed using "to" include the numerical values ​​before and after the range as the lower and upper limits, respectively.

[0010] There is a demand for more precise design of impedance adjustment of signal conductors in wiring boards. Therefore, the present disclosure provides a wiring board, a package, and an optical module that can adjust the impedance so that it does not become too large compared to a desired value.

[0011] 1 to 3 , the wiring board 1 of the present disclosure includes a first insulating base 11, a first ground conductor 31, and a first signal conductor 33. The first insulating base 11 has a first upper surface 111, a first side surface 112 connected to the first upper surface 111, and a first notch portion 21 cut out from the first upper surface 111 to the first side surface 112. The first ground conductor 31 has a first portion 311 located on the first upper surface 111 and extending from a line overlapping the first side surface 112 in a plan view, and a second portion 312 located within the first notch portion 21 and connected to the first portion 311. The "line overlapping the first side surface 112 in a plan view" can be rephrased as a "first imaginary line."

[0012] The first ground conductor 31 has the second portion 312, which strengthens the ground potential. Furthermore, the first ground conductor 31 has the second portion 312, which makes it easier for the bonding material to form a fillet when the first ground external terminal 41 (described later) is connected to the first ground conductor 31. This improves the bonding strength between the first ground conductor 31 and the first ground external terminal 41.

[0013] The first portion 311 surrounds at least a portion of the first cutout portion 21 in a plan view. The first portion 311 may surround the entire first cutout portion 21 in a plan view, or may surround only a portion of the first cutout portion 21. "The first portion 311 surrounds the entire first cutout portion 21" refers to, for example, a state in which the first portion 311 surrounds all three of the three sides of the first cutout portion 21 on the first upper surface 111. "The first portion 311 surrounds only a portion of the first cutout portion 21" refers to, for example, a state in which the first portion 311 surrounds only two of the three sides of the first cutout portion 21 on the first upper surface 111.

[0014] The first signal conductor 33 is positioned alongside the first ground conductor 31 in a first direction on the first upper surface 111. The first direction is the X direction in Fig. 1 and other figures. Another conductor may or may not be positioned between the first ground conductor 31 and the first signal conductor 33 in the first direction on the first upper surface 111.

[0015] 1 , on a line overlapping with the first side surface 112 in a plan view, a distance D1 between the center 31 c of the first ground conductor 31 and the first signal conductor 33 is smaller than a distance D2 between the center 21 c of the first cutout portion 21 and the first signal conductor 33. In other words, when the edge of the first portion 311 facing the first signal conductor 33 is defined as a first edge 313 and the edge opposite to the first edge 313 is defined as a second edge 314, a distance D3 in the first direction from the "center 21 c of the first cutout portion 21 on the line overlapping with the first side surface 112 in a plan view" to the first edge 313 is larger than a distance D4 in the first direction from the "center 21 c of the first cutout portion 21 on the line overlapping with the first side surface 112 in a plan view" to the second edge 314. In this disclosure, "distance" means the shortest distance unless otherwise specified.

[0016] Because the distance D1 is smaller than the distance D2, the first ground conductor 31 can be brought closer to the first signal conductor 33 without bringing the first cutout 21 too close to the first signal conductor 33. Because the first cutout 21 is not too close to the first signal conductor 33, the impedance of the first signal conductor 33 can be more easily adjusted appropriately. Furthermore, because the first cutout 21 is not too close to the first signal conductor 33, the possibility of distortion of the first upper surface 111, specifically the portion of the first upper surface 111 where the first signal conductor 33 contacts, during formation of the first cutout 21 is reduced, resulting in a deviation in the impedance of the first signal conductor 33. Because the first ground conductor 31 is close to the first signal conductor 33, the capacitance component of the first signal conductor 33 can be increased. This allows the impedance of the first signal conductor 33 to be adjusted so that it does not become too large compared to a desired value.

[0017] The first edge 313 and the second edge 314 may be linear as shown in Fig. 1 or the like, or may not be linear as shown in Fig. 9. The dimension of the first ground conductor 31 in the first direction, i.e., the width of the first ground conductor 31, may not be constant as shown in Fig. 9.

[0018] The dimension of the first ground conductor 31 on the line overlapping with the first side surface 112 in a plan view may be larger than the dimension of the first signal conductor 33. This further strengthens the ground potential. The dimension of the first ground conductor 31 on the line overlapping with the first side surface 112 in a plan view is the dimension in the first direction of the end of the first portion 311 on the first side surface 112 side. The dimension of the first signal conductor 33 on the line overlapping with the first side surface 112 in a plan view is the dimension in the first direction of the end of the fifth portion 331 (described later) on the first side surface 112 side. Note that in the present disclosure, the "dimension in the first direction" of each conductor can be rephrased as "width."

[0019] The first cutout portion 21 may have a first inner wall surface 211 connected to the first top surface 111 and a first bottom surface 212 connected to the first inner wall surface 211. In this case, the second portion 312 may be located on the first inner wall surface 211 and the first bottom surface 212. By having the second portion 312 located on the first inner wall surface 211 and the first bottom surface 212, the ground potential is further strengthened compared to, for example, a case in which the second portion 312 is located only on the first inner wall surface 211. Furthermore, by having the second portion 312 located on the first inner wall surface 211 and the first bottom surface 212, when the first ground external terminal 41 (described later) is connected to the first ground conductor 31, the bonding material is more likely to connect to the first ground conductor 31 on the first bottom surface 212, thereby forming a fillet. This further improves the bonding strength between the first ground conductor 31 and the first ground external terminal 41.

[0020] 1 and other figures, the wiring board 1 may include a second ground conductor 32 located on the first upper surface 111 on the opposite side of the first ground conductor 31 with the first signal conductor 33 interposed therebetween. In this case, the first signal conductor 33 is located between the first ground conductor 31 and the second ground conductor 32. By including the second ground conductor 32 in the wiring board 1, the ground potential is further strengthened.

[0021] In the first direction on the first upper surface 111 , another conductor may or may not be located between the second ground conductor 32 and the first signal conductor 33 .

[0022] 1 to 3 , the first insulating base 11 may include a second cutout portion 22 cut out from the first upper surface 111 to the first side surface 112. The second ground conductor 32 may include a third portion 321 located on the first upper surface 111 and extending from a line overlapping with the first side surface 112 in a plan view, and a fourth portion 322 located within the second cutout portion 22 and connected to the third portion 321.

[0023] The second ground conductor 32 has the fourth portion 322, which further strengthens the ground potential. Furthermore, the second ground conductor 32 has the fourth portion 322, which makes it easier for the bonding material to form a fillet when the second ground external terminal 42 (described later) is connected to the second ground conductor 32. This improves the bonding strength between the second ground conductor 32 and the second ground external terminal 42.

[0024] The second cutout portion 22 may have a second inner wall surface 221 connected to the first top surface 111 and a second bottom surface 222 connected to the second inner wall surface 221. In this case, the fourth portion 322 may be located on the second inner wall surface 221 and the second bottom surface 222. By having the fourth portion 322 located on the second inner wall surface 221 and the second bottom surface 222, the ground potential is further strengthened compared to, for example, when the fourth portion 322 is located only on the second inner wall surface 221. Furthermore, by having the fourth portion 322 located on the second inner wall surface 221 and the second bottom surface 222, when the second ground external terminal 42 (described later) is connected to the second ground conductor 32, the bonding material is more likely to extend to the second ground conductor 32 on the second bottom surface 222, thereby forming a fillet. This further improves the bonding strength between the second ground conductor 32 and the second ground external terminal 42.

[0025] The third portion 321 may surround at least a portion of the second cutout portion 22 in a plan view. In this case, the third portion 321 may surround the entire second cutout portion 22 in a plan view, or may surround only a portion of the second cutout portion 22. "The third portion 321 surrounding the entire second cutout portion 22" refers to, for example, a state in which the first portion 311 surrounds all three of the three sides of the second cutout portion 22 on the first upper surface 111. "The third portion 321 surrounding only a portion of the second cutout portion 22" refers to, for example, a state in which the first portion 311 surrounds only two of the three sides of the second cutout portion 22 on the first upper surface 111.

[0026] 1 , on a line overlapping with the first side surface 112 in a plan view, a distance D5 between the center 32 c of the second ground conductor 32 and the first signal conductor 33 may be smaller than a distance D6 between the center 22 c of the second cutout portion 22 and the first signal conductor 33. In other words, when the edge of the third portion 321 facing the first signal conductor 33 is defined as a third edge 323 and the edge opposite to the third edge 323 is defined as a fourth edge 324, a distance D7 in the first direction from the “center 22 c of the second cutout portion 22 on the line overlapping with the first side surface 112 in a plan view” to the third edge 323 is larger than a distance D8 in the first direction from the “center 22 c of the second cutout portion 22 on the line overlapping with the first side surface 112 in a plan view” to the fourth edge 324.

[0027] Because the distance D5 is smaller than the distance D6, the second ground conductor 32 can be brought closer to the first signal conductor 33 without being too close to the first signal conductor 33. Because the second cutout 22 is not too close to the first signal conductor 33, the impedance of the first signal conductor 33 can be more easily adjusted appropriately. Furthermore, because the second cutout 22 is not too close to the first signal conductor 33, the possibility of distortion of the first upper surface 111, specifically the portion of the first upper surface 111 where the first signal conductor 33 contacts, during formation of the second cutout 22 is reduced, resulting in a deviation in the impedance of the first signal conductor 33. Because the second ground conductor 32 is close to the first signal conductor 33, the capacitance component of the first signal conductor 33 can be increased. This makes it easier to adjust the impedance of the first signal conductor 33 so that it does not become too large compared to a desired value.

[0028] The third edge 323 and the fourth edge 324 may be linear as shown in Fig. 1 or may not be linear as shown in Fig. 9. The dimension of the second ground conductor 32 in the first direction, i.e., the width of the second ground conductor 32, may not be constant as shown in Fig. 9.

[0029] The dimension of the second ground conductor 32 on the line overlapping with the first side surface 112 in a plan view may be larger than the dimension of the first signal conductor 33. This further strengthens the ground potential. The dimension of the second ground conductor 32 on the line overlapping with the first side surface 112 in a plan view is the dimension in the first direction of the end of the third portion 321 on the first side surface 112 side.

[0030] 1 to 3 , the first insulating base 11 may include a third notch portion 23 that is cut out from the first upper surface 111 to the first side surface 112. The first signal conductor 33 may have a fifth portion 331 that is located on the first upper surface 111 and connected to the third notch portion 23, and a sixth portion 332 that is located within the third notch portion 23 and connected to the fifth portion 331. The fifth portion 331 may extend from a line that overlaps with the first side surface in a plan view.

[0031] The sixth portion 332 of the first signal conductor 33 makes it easier for the bonding material to form a fillet when the second external ground terminal 42 (described later) is connected to the second ground conductor 32. This improves the bonding strength between the second ground conductor 32 and the second external ground terminal 42.

[0032] The third cutout portion 23 may have a third inner wall surface 231 connected to the first top surface 111 and a third bottom surface 232 connected to the third inner wall surface 231. The third bottom surface 232 may be exposed. An example of an exposed state of the third bottom surface 232 is a state in which the sixth portion 332 is located on the third inner wall surface 231 but not on the third bottom surface 232. The sixth portion 332 not being located on the third bottom surface 232 makes it easier to adjust the impedance of the first signal conductor 33. Furthermore, the sixth portion 332 not being located on the third bottom surface 232 makes it difficult for the bonding material to spread to the third bottom surface 232 when a first external signal terminal 43 (described later) is connected to the first signal conductor 33. This reduces the amount of bonding material, thereby reducing the possibility of the impedance of the first signal conductor 33 being misaligned.

[0033] The fifth portion 331 may surround at least a portion of the third cutout portion 23 in a plan view. In this case, the fifth portion 331 may surround the entire third cutout portion 23 in a plan view, or may surround only a portion of the third cutout portion 23. "The fifth portion 331 surrounds the entire third cutout portion 23" refers to, for example, a state in which the fifth portion 331 surrounds all three of the three sides of the third cutout portion 23 on the first upper surface 111. "The fifth portion 331 surrounds only a portion of the third cutout portion 23" refers to, for example, a state in which the fifth portion 331 surrounds only two of the three sides of the third cutout portion 23 on the first upper surface 111.

[0034] On the line overlapping with the first side surface 112 in a plan view, the distance between the first notch portion 21 and the third notch portion 23 may be the same as the distance between the second notch portion 22 and the third notch portion 23. Here, "the same" allows for an error of several tens to several hundreds of μm.

[0035] 1 and other figures, the wiring board 1 may include a power supply conductor 34 located on the first upper surface 111 on the opposite side of the first signal conductor 33 with the first ground conductor 31 in between. In this case, the first ground conductor 31 is located between the first signal conductor 33 and the power supply conductor 34.

[0036] In the first direction on the first upper surface 111, another conductor may or may not be located between the first ground conductor 31 and the power supply conductor 34.

[0037] The dimension of the first signal conductor 33 on the line overlapping with the first side surface 112 in plan view may be larger than the dimension of the power supply conductor 34. This makes it easier to adjust the impedance of the first signal conductor 33 so that it does not become too large compared to a desired value.

[0038] 1 to 3 , the first insulating base 11 may have a fourth notch portion 24 cut out from the first upper surface 111 to the first side surface 112. The power supply conductor 34 may have a seventh portion 341 located on the first upper surface 111 and connected to the fourth notch portion 24, and an eighth portion 342 located within the fourth notch portion 24 and connected to the seventh portion 341. The seventh portion 341 may extend from a line overlapping the first side surface in a plan view.

[0039] The power supply conductor 34 having the eighth portion 342 makes it easier for the bonding material to form a fillet when the power supply external terminal 44 (described later) is connected to the power supply conductor 34. This improves the bonding strength between the power supply conductor 34 and the power supply external terminal 44.

[0040] The fourth cutout portion 24 may have a fourth inner wall surface 241 that connects to the first top surface 111 and a fourth bottom surface 242 that connects to the fourth inner wall surface 241. The fourth bottom surface 242 may be exposed. An exposed state of the fourth bottom surface 242 is, for example, a state in which the eighth portion 342 is located on the fourth inner wall surface 241 but not on the fourth bottom surface 242. When the eighth portion 342 is not located on the fourth bottom surface 242, the possibility of causing an impedance deviation with respect to a nearby signal conductor is reduced.

[0041] The seventh portion 341 may surround at least a portion of the fourth cutout portion 24 in a plan view. In this case, the seventh portion 341 may surround the entire fourth cutout portion 24 in a plan view, or may surround only a portion of the fourth cutout portion 24. "The seventh portion 341 surrounds the entire fourth cutout portion 24" refers to, for example, a state in which the seventh portion 341 surrounds all three of the three sides of the fourth cutout portion 24 on the first upper surface 111. "The seventh portion 341 surrounds only a portion of the fourth cutout portion 24" refers to, for example, a state in which the seventh portion 341 surrounds only two of the three sides of the fourth cutout portion 24 on the first upper surface 111.

[0042] 7 to 9, the corners of each notch, such as the first notch 21, may be arc-shaped in plan view, which relieves stress and reduces the possibility of breakage and / or distortion of the wiring substrate 1.

[0043] Each notch portion, such as the first notch portion 21, may be cut out from the first upper surface 111 of the first insulating base 11 to the lower surface, or may be cut out partway toward the lower surface rather than from the first upper surface 111 to the lower surface of the first insulating base 11 as shown in Figure 2, etc.

[0044] The dimensions and shapes of each notch, such as the first notch 21, may be the same or different from one another. If the dimensions and shapes of each notch are the same, it becomes easier to manufacture the wiring board 1 and adjust the impedance of the first signal conductor 33. The dimensions of each notch refer to the dimensions in the X-axis direction (first direction), the Y-axis direction, and the Z-axis direction.

[0045] 2, 3, and 5, the first insulating base 11 may have a first layer 114 having a first upper surface 111 and a first inner wall surface 211, and a second layer 115 located below the first layer 114. The first layer 114 may have a second inner wall surface 221, a third inner wall surface 231, and a fourth inner wall surface 241. The second layer 115 may have a second upper surface 113 including a first bottom surface 212. The second upper surface 113 may include a second bottom surface 222, a third bottom surface 232, and a fourth bottom surface 242. The second upper surface 113 may be defined as the surface on which a first inner-layer ground conductor 51 (described later) is located.

[0046] 3 and 6, the wiring board 1 may include a first inner-layer ground conductor 51 located between the first layer 114 and the second layer 115. This further strengthens the ground potential. The first inner-layer ground conductor 51 may be located on the second upper surface 113. Note that in FIG. 6, the first signal conductor 33 and the power supply conductor 34 are shown by dashed lines as being located on the first upper surface 111, not on the second upper surface 113.

[0047] The first inner-layer ground conductor 51 may be connected to the second portion 312 and exposed on the first side surface 112. In this case, as shown in FIG. 6 , on a line overlapping the first side surface 112 in a plan view, the distance d1 between the center 51c of the first inner-layer ground conductor 51 and the first signal conductor 33 may be smaller than the distance d2 between the center 21c of the first cutout portion 21 and the first signal conductor 33. Compared to when the distances d1 and d2 are the same, making the distance d1 smaller than the distance d2 increases the capacitance component of the first signal conductor 33. This allows the impedance of the first signal conductor 33 to be adjusted so that it does not become too large compared to a desired value.

[0048] 3 and 6, the wiring board 1 may include a second inner-layer ground conductor 52 located between the first layer 114 and the second layer 115. This further strengthens the ground potential. The second inner-layer ground conductor 52 may be located on the second upper surface 113.

[0049] The second inner-layer ground conductor 52 may be connected to the fourth portion 322 and exposed on the first side surface 112. In this case, as shown in FIG. 6 , on a line overlapping the first side surface 112 in a plan view, a distance d5 between the center 52c of the second inner-layer ground conductor 52 and the first signal conductor 33 may be smaller than a distance d6 between the center 22c of the second cutout portion 22 and the first signal conductor 33. Compared to when the distances d5 and d6 are the same, making the distance d5 smaller than the distance d6 increases the capacitance component of the first signal conductor 33. This allows the impedance of the first signal conductor 33 to be adjusted so that it does not become too large compared to a desired value.

[0050] The first inner layer ground conductor 51 and the second inner layer ground conductor 52 may be electrically connected, or may be formed into a single continuous conductor by a conductor extending from the first inner layer ground conductor 51 to the second inner layer ground conductor 52.

[0051] The wiring board 1 may not have an inner layer conductor located between the first layer 114 and the second layer 115 and connected to the first signal conductor 33. In other words, the inner layer conductor may not be located at a position that overlaps with the first signal conductor 33 in a plan view.

[0052] The wiring board 1 does not have to have an inner layer conductor located between the first layer 114 and the second layer 115 and connected to the power supply conductor 34. In other words, the inner layer conductor does not have to be located at a position that overlaps with the power supply conductor 34 in a plan view.

[0053] 4 and 6 , the wiring board 1 may include a first via conductor 53 that penetrates the first layer 114 and is connected to the first ground conductor 31 and the first inner-layer ground conductor 51. In addition, in a plan view, the distance between the first via conductor 53 and the first signal conductor 33 may be smaller than the distance between the first cutout portion 21 and the first signal conductor 33. This further strengthens the ground potential.

[0054] 4 and 6 , the wiring board 1 may include a second via conductor 54 that penetrates the first layer 114 and is connected to the second ground conductor 32 and the second inner-layer ground conductor 52. In addition, in a plan view, the distance between the second via conductor 54 and the first signal conductor 33 may be smaller than the distance between the second cutout portion 22 and the first signal conductor 33. This further strengthens the ground potential.

[0055] When the wiring board 1 includes the first external ground terminal 41, the first via conductor 53 does not need to overlap, in plan view, with the conductor portion of the first external ground terminal 41. This reduces the possibility that the reliability of the electrical connection between the first external ground conductor 31 and the first external ground terminal 41 will be impaired, even if the first upper surface 111 is uneven due to the presence of the first via conductor 53.

[0056] When the wiring board 1 includes the second external ground terminal 42, the second via conductor 54 does not need to overlap, in plan view, with the conductor portion of the second external ground terminal 42. This reduces the possibility that the reliability of the electrical connection between the second external ground conductor 32 and the second external ground terminal 42 will be impaired, even if the first upper surface 111 is uneven due to the presence of the second via conductor 54.

[0057] As shown in FIG. 4 and other figures, the wiring board 1 may include a second insulating base 12 located on the first upper surface 111, the first ground conductor 31, and the first signal conductor 33. The second insulating base 12 may be located on conductors such as the second ground conductor 32 and the power supply conductor 34. The second insulating base 12 may have a third upper surface 121, a second side surface 122, and a third side surface 123. The second side surface 122 may be connected to the third upper surface 121 and in contact with the first upper surface 111. The third side surface 123 may be connected to the third upper surface 121 on the side opposite the second side surface 122 and in contact with the first upper surface 111. For example, the second side surface 122 is located on the side of the first side surface 112, and the third side surface 123 is located on the opposite side.

[0058] As shown in FIG. 4 and other figures, the wiring board 1 may include a first coating portion 55 located along the second side surface 122 on the first ground conductor 31 and the first signal conductor 33. The first coating portion 55 may be located on conductors such as the second ground conductor 32 and the power supply conductor 34. By including the first coating portion 55 in the wiring board 1, when plating is applied to conductors such as the first signal conductor 33, the possibility of the plating traveling along the second side surface 122 and shorting the conductors together is reduced. Furthermore, by including the first coating portion 55 in the wiring board 1, the possibility of conductors such as the first signal conductor 33 peeling off from the first upper surface 111 is reduced. Furthermore, by including the first coating portion 55 in the wiring board 1, the possibility of the bonding material spreading more than desired when bonding external terminals such as the first external signal terminal 43 is reduced.

[0059] 4 and other drawings, the wiring board 1 may include a second coating portion 56 located along the third side surface 123 on the first ground conductor 31 and the first signal conductor 33. The second coating portion 56 may be located on conductors such as the second ground conductor 32 and the power supply conductor 34. By including the second coating portion 56 on the wiring board 1, when plating is applied to conductors such as the first signal conductor 33, the possibility of the plating traveling along the third side surface 123 and shorting the conductors together is reduced. Furthermore, by including the second coating portion 56 on the wiring board 1, the possibility of conductors such as the first signal conductor 33 peeling off from the first upper surface 111 is reduced.

[0060] The distance between the first via conductor 53 and the second insulating base 12 may be closer than the distance between the first via conductor 53 and the first side surface 112. This may cause impedance fluctuations in the portion of the first signal conductor 33 exposed from the second insulating base 12, but the impedance can be adjusted by strengthening the ground potential. Furthermore, the first via conductor 53 is less likely to interfere with the bonding of the first ground external terminal 41. Furthermore, by separating the first via conductor 53 from the first notch portion 21, the ceramic green sheet is less likely to tear when the first insulating base 11 is manufactured from the ceramic green sheet. The first via conductor 53 may overlap the second insulating base 12 in a plan view, or may overlap the first coating portion 55 in a plan view.

[0061] Similarly, the distance between the second via conductor 54 and the second insulating base 12 may be closer than the distance between the second via conductor 54 and the first side surface 112. This may cause impedance fluctuations in the portion of the first signal conductor 33 exposed from the second insulating base 12, but the impedance can be adjusted by strengthening the ground potential. Furthermore, the second via conductor 54 is less likely to interfere with the bonding of the second external ground terminal 42. Furthermore, by separating the second via conductor 54 from the second cutout portion 22, the ceramic green sheet is less likely to tear when the first insulating base 11 is manufactured from the ceramic green sheet. The second via conductor 54 may overlap the second insulating base 12 in a plan view, or may overlap the first coating portion 55 in a plan view.

[0062] 4 and other figures, the wiring board 1 may include a first ground external terminal 41 electrically connected to the first ground conductor 31. On a line overlapping the first side surface 112 in a plan view, the entire first ground external terminal 41 may overlap the first cutout portion 21. This brings the bonding material into contact with the entire lower surface of the first ground external terminal 41 at the position overlapping the first cutout portion 21, thereby improving the bonding strength between the first ground conductor 31 and the first ground external terminal 41.

[0063] 4 and other figures, the wiring board 1 may include a second external ground terminal 42 electrically connected to the second external ground conductor 32. On a line overlapping the first side surface 112 in a plan view, the entire second external ground terminal 42 may overlap the second cutout portion 22. This improves the bonding strength between the second external ground conductor 32 and the second external ground terminal 42.

[0064] 4 and other figures, the wiring board 1 may include first external signal terminals 43 electrically connected to the first signal conductors 33. All of the first external signal terminals 43 may overlap the third cutout portions 23 on a line overlapping the first side surface 112 in a plan view. This improves the bonding strength between the first signal conductors 33 and the first external signal terminals 43.

[0065] 4 and other figures, the wiring board 1 may include external power supply terminals 44 electrically connected to the power supply conductors 34. All of the external power supply terminals 44 may overlap the fourth cutout portions 24 on a line overlapping the first side surface 112 in a plan view. This improves the bonding strength between the power supply conductors 34 and the external power supply terminals 44.

[0066] The distance between the first ground external terminal 41 and the first signal external terminal 43 may be the same as the distance between the second ground external terminal 42 and the first signal external terminal 43. This makes it easier to join each external terminal to each conductor. Furthermore, each external terminal can stably electrically connect each conductor of the wiring board 1 to each conductor of the external board. Note that the "distance" here can be rephrased as the distance on a line that overlaps with the first side surface 112 in a plan view. Here, "the same" allows for an error of several tens to several hundreds of μm.

[0067] Each external terminal and each conductor may be bonded with a bonding material. The bonding material is, for example, a metal brazing material. The bonding material forms a fillet within a notch such as the first notch 21, thereby improving the bonding strength between each external terminal and each conductor. If the notch is rectangular in plan view, even if the depth (dimension in the Y direction) of the notch is narrow, the width (dimension in the X direction) of the notch and the external terminal is wide, thereby increasing the bonding area with the external terminal. This makes it easier for the bonding material to form a fillet, improving the bonding strength between each external terminal and each conductor. Therefore, each external terminal is stably electrically connected to the external board.

[0068] The wiring board 1 may have other conductors (e.g., control signal conductors) located on the first upper surface 111. The wiring board 1 may also have other external terminals 47 electrically connected to the other conductors, as shown in Figures 10 and 11 .

[0069] The external terminals such as the first ground external terminal 41 are not particularly limited and may be lead terminals or terminals of a substrate such as an FPC (flexible printed circuit board) or a PCB (printed circuit board). Terminals of the substrate such as an FPC or PCB may be connected in parallel to the lead terminals to the conductors of the wiring substrate 1. For example, lead terminals may be connected to the first ground conductor 31, the second ground conductor 32, and the first signal conductor 33, respectively, and terminals of the substrate such as an FPC or PCB may be connected to the power supply conductor 34 and other conductors.

[0070] As shown in FIG. 7 , the wiring board 1 may include, for example, a second signal conductor 35 between the second ground conductor 32 and the first signal conductor 33. In this case, the first ground conductor 31, the first signal conductor 33, the second signal conductor 35, and the second ground conductor 32 may form a GSSG structure. The GSSG structure is a differential line structure composed of multiple conductors arranged in the following order: ground conductor-signal conductor-signal conductor-ground conductor. On a line overlapping the first side surface 112 in a plan view, the distance between the first signal conductor 33 and the second signal conductor 35 may be larger than the distance between the first ground conductor 31 and the first signal conductor 33. Furthermore, on a line overlapping the first side surface 112 in a plan view, the distance between the first signal conductor 33 and the second signal conductor 35 may be larger than the distance between the second ground conductor 32 and the second signal conductor 35.

[0071] 7 , the first insulating base 11 may include a fifth notch portion 25 that is cut out from the first upper surface 111 to the first side surface 112. The second signal conductor 35 may have a ninth portion 351 that is located on the first upper surface 111 and extends from a line that overlaps with the first side surface 112 in a plan view, and a tenth portion that is located within the fifth notch portion 25 and is connected to the ninth portion 351.

[0072] As shown in FIG. 8 , the wiring board 1 may include, for example, a third ground conductor 36 between the first signal conductor 33 and the second signal conductor 35. In this case, the first ground conductor 31, the first signal conductor 33, the third ground conductor 36, the second signal conductor 35, and the second ground conductor 32 may form a GSGSG structure. The GSGSG structure is a differential line structure composed of multiple conductors arranged in the following order: ground conductor-signal conductor-ground conductor-signal conductor-ground conductor. On a line overlapping the first side surface 112 in a plan view, the distance between the first signal conductor 33 and the third ground conductor 36 may be the same as the distance between the first signal conductor 33 and the first ground conductor 31. Furthermore, on a line overlapping the first side surface 112 in a plan view, the distance between the second signal conductor 35 and the third ground conductor 36 may be the same as the distance between the second signal conductor 35 and the second ground conductor 32. Here, "same" allows for an error of several tens to several hundreds of micrometers.

[0073] 8 , the first insulating base 11 may include a sixth notch portion 26 that is cut out from the first upper surface 111 to the first side surface 112. The third ground conductor 36 may have an eleventh portion 361 that is located on the first upper surface 111 and extends from a line that overlaps with the first side surface 112 in a plan view, and a twelfth portion that is located within the sixth notch portion 26 and connects to the eleventh portion 361. On the line that overlaps with the first side surface 112 in a plan view, a center 36c of the third ground conductor 36 and a center 26c of the sixth notch portion 26 may be at the same position.

[0074] 7 , the first insulating base 11 may have slits 116 formed between the conductors, for example, between the first signal conductor 33 and the second signal conductor 35, for the purpose of reducing the dielectric constant. The slits 116 may extend to the first side surface 112 or may penetrate the first insulating base 11. Furthermore, when the wiring board 1 has a second insulating base 12, the slits 116 may extend to the second side surface 122.

[0075] The material of the first insulating base 11, the second insulating base 12, the first coating portion 55, and the second coating portion 56 may be, for example, ceramic. These components may be primarily composed of ceramic. The term "primary component" refers to a component that accounts for 60% by mass or more. Examples of ceramic include aluminum oxide sintered body (alumina ceramic), aluminum nitride sintered body, silicon carbide sintered body, mullite sintered body, and glass ceramic. When the first insulating base 11 and the second insulating base 12 are primarily composed of ceramic, the heat dissipation and rigidity of the wiring board 1 are improved. The first insulating base 11 and the second insulating base 12 may also contain a resin. Examples of resins include epoxy resin, polyimide, and liquid crystal polymer. The first insulating base 11 and the second insulating base 12 may contain multiple types of resin materials, and may also contain components other than resin, such as inorganic materials such as silica or rubber materials.

[0076] Examples of the material of each conductor include tungsten, molybdenum, manganese, copper, silver, palladium, gold, platinum, nickel, cobalt, alloys thereof, etc. The material of each conductor may be the same as or different from each other.

[0077] The wiring substrate 1 can be manufactured, for example, as follows. In the following example, the first insulating base 11 is made of an aluminum oxide sintered body, and the conductors are made of tungsten. First, the raw material powder for the first insulating base 11 is mixed with an organic solvent and an organic binder to form a slurry. The raw material powder mainly contains aluminum oxide powder and a sintering aid powder such as silicon oxide. 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. To form via conductors, through holes are formed at predetermined positions on the ceramic green sheet, and the through holes are filled with the metal paste. Metal paste for forming signal conductors and ground conductors is printed at predetermined positions on the 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 to obtain the wiring substrate 1. If necessary, external terminals are bonded to the signal conductors and ground conductors, respectively.

[0078] [Package] As shown in FIG. 10 , the package 62 includes a wiring substrate 1 and a frame 63 bonded to the wiring substrate 1. The package 62 may also include a base 64 located below the wiring substrate 1 and the frame 63, and a cylindrical body 65 provided on a side of the frame 63. The frame 63, the base 64, and the cylindrical body 65 may be made of materials such as ceramic, metal, or resin, and may be the same or different from one another. The cylindrical body 65 is used to secure, for example, a translucent member, an optical fiber, or the like, and to input and output optical signals. The package 62 may include one or more wiring substrates 1. The frame 63 may be separate from the wiring substrate 1 as shown in FIG. 10 , or may be integrally molded with the first insulating base 11 of the wiring substrate 1. If the frame 63 and the first insulating base 11 are made of the same material, the first insulating base 11 and the frame 63 can be easily integrally molded.

[0079] [Optical Module] As shown in FIG. 11, an optical module 61 includes a package 62 , an optical element 68 mounted in the package 62 , and a lid 66 joined to the package 62 .

[0080] The optical element 68 may be, for example, a light-receiving element capable of converting light into an electrical signal or a light-emitting element capable of converting an electrical signal into light. The optical element 68 may be, for example, an optical semiconductor element. The light-receiving element may also be referred to as an optical sensor or a photodetector. Examples of light-receiving elements include a photodiode (PD) and a complementary metal-oxide-semiconductor (CMOS). Examples of light-emitting elements include a light-emitting diode (LED), a laser diode (LD), and a surface-emitting element. The optical module 61 may include multiple optical elements 68, or may include different types of optical elements 68, such as a light-emitting element and a light-receiving element. The optical element 68 may be electrically connected to a conductor, such as the first signal conductor 33, provided on the wiring substrate 1 via a bonding wire 69. The optical element 68 may be mounted on the package 62 via a submount or the like.

[0081] The lid 66 is provided to reduce the intrusion of foreign matter such as moisture and fine particles into the interior (cavity) of the optical module 61. The lid 66 may be a plate made of ceramic, metal, resin, or the like, or may be a substrate such as a PCB (printed circuit board).

[0082] The lid 66 may be joined to the package 62 via a seal ring 67. The seal ring 67 may be made of a material that has excellent weldability with the lid 66, such as copper, tungsten, iron, nickel, cobalt, or an alloy thereof.

[0083] The optical module 61 may be used for optical communication or LiDAR (light detection and ranging). Specifically, the optical module 61 may be used for LiDAR for in-vehicle components.

[0084]

[0013] The following are further examples of embodiments of the wiring board, package, and optical module according to the present disclosure. (1) One embodiment of the wiring board according to the present disclosure includes: a first insulating base having a first top surface, a first side surface connected to the first top surface, and a first cutout portion cut out from the first top surface to the first side surface, a first ground conductor having a first portion located on the first top surface and extending from a line overlapping the first side surface in a plan view, and a second portion located within the first cutout portion and connected to the first portion, and a first signal conductor located on the first top surface and aligned with the first ground conductor in a first direction, wherein the first portion surrounds at least a portion of the first cutout portion in a plan view, and a distance between a center of the first ground conductor and the first signal conductor on the line overlapping the first side surface in a plan view is smaller than a distance between a center of the first cutout portion and the first signal conductor.

[0085] (2) One embodiment of the wiring board according to the present disclosure is the wiring board of (1) above, wherein the dimensions of the first ground conductor are larger than the dimensions of the first signal conductor on a line that overlaps the first side surface in a planar view.

[0086] (3) One embodiment of the wiring board according to the present disclosure is the wiring board of (1) or (2) above, wherein the first cutout portion has a first inner wall surface connected to the first top surface and a first bottom surface connected to the first inner wall surface, and the second portion is located on the first inner wall surface and the first bottom surface.

[0087] (4) One embodiment of the wiring board according to the present disclosure is the wiring board according to any one of (1) to (3) above, wherein, in a plan view, corners of the first cutout portion are arc-shaped.

[0088] (5) One embodiment of the wiring board according to the present disclosure is the wiring board of any one of (1) to (4) above, further comprising a second ground conductor located on the first upper surface on the opposite side of the first ground conductor with the first signal conductor in between.

[0089] (6) One embodiment of the wiring board according to the present disclosure is the wiring board of (5) above, wherein the first insulating base further comprises a second notch portion cut out from the first top surface to the first side surface, the second ground conductor has a third portion located on the first top surface and extending from a line overlapping with the first side surface in a planar view, and a fourth portion located within the second notch portion and connected to the third portion, the third portion surrounding at least a portion of the second notch portion in a planar view, and the distance between the center of the second ground conductor and the first signal conductor on the line overlapping with the first side surface in a planar view is smaller than the distance between the center of the second notch portion and the first signal conductor.

[0090] (7) One embodiment of the wiring board according to the present disclosure is the wiring board of any one of (1) to (6) above, further comprising a power supply conductor located on the first upper surface opposite the first signal conductor with the first ground conductor interposed therebetween.

[0091] (8) One embodiment of the wiring board according to the present disclosure is the wiring board of any of (1) to (7) above, wherein the first insulating base further comprises a third notch portion cut out from the first upper surface to the first side surface, and the first signal conductor has a fifth portion located on the first upper surface and connected to the third notch portion, and a sixth portion located within the third notch portion and connected to the fifth portion.

[0092] (9) One embodiment of the wiring board according to the present disclosure is the wiring board of (8) above, wherein the third cutout portion has a third inner wall surface connected to the first upper surface and a third bottom surface connected to the third inner wall surface, and the third bottom surface is exposed.

[0093] (10) One embodiment of the wiring board according to the present disclosure is the wiring board of any of (1) to (9) above, wherein the first insulating base has a first layer having the first upper surface and a second layer located below the first layer, and further comprises a first inner-layer ground conductor located between the first layer and the second layer, and a first via conductor penetrating the first layer and connecting to the first ground conductor and the first inner-layer ground conductor, and in a planar view, the distance between the first via conductor and the first signal conductor is smaller than the distance between the first cutout portion and the first signal conductor.

[0094] (11) One embodiment of the wiring board according to the present disclosure is the wiring board of any one of (1) to (10) above, further comprising a second insulating base positioned on the first upper surface, the first ground conductor, and the first signal conductor.

[0095] (12) One embodiment of the wiring board according to the present disclosure is the wiring board of (11) above, wherein the second insulating base has a third upper surface and a second side surface connected to the third upper surface and in contact with the first upper surface, and further includes a first coating portion located along the second side surface on the first ground conductor and the first signal conductor.

[0096] (13) One embodiment of the wiring board according to the present disclosure is the wiring board of any one of (1) to (12) above, further comprising: a first external ground terminal electrically connected to the first ground conductor; and a first external signal terminal electrically connected to the first signal conductor.

[0097] (14) One embodiment of the wiring board according to the present disclosure is the wiring board of (13) above, wherein all of the first ground external terminals overlap the first cutout portion on a line that overlaps the first side surface in a planar view.

[0098] (15) One embodiment of the wiring board according to the present disclosure is the wiring board of (5) or (6) above, further comprising: a first external ground terminal electrically connected to the first ground conductor; a first external signal terminal electrically connected to the first signal conductor; and a second external ground terminal electrically connected to the second ground conductor, wherein the spacing between the first external ground terminal and the first external signal terminal is the same as the spacing between the second external ground terminal and the first external signal terminal.

[0099] (16) One embodiment of the wiring board according to the present disclosure is the wiring board of any of (1) to (15) above, wherein the first cutout portion has a first inner wall surface connected to the first top surface and a first bottom surface connected to the first inner wall surface, the first insulating base has a first layer having the first top surface and the first inner wall surface and a second layer located below the first layer, the second layer has a second top surface including the first bottom surface, the second portion is located on the first inner wall surface and the first bottom surface, and further comprises a first inner-layer ground conductor located on the second top surface, the first inner-layer ground conductor is connected to the second portion and is exposed at the first side surface, and on a line overlapping the first side surface in a plan view, the distance between the center of the first inner-layer ground conductor and the first signal conductor is smaller than the distance between the center of the first cutout portion and the first signal conductor.

[0100] (17) One embodiment of a package according to the present disclosure includes: a wiring board according to any one of (1) to (16) above; and a frame body joined to the wiring board.

[0101] (18) An embodiment of an optical module according to the present disclosure includes the package of (17) above; an optical element mounted in the package; and a lid joined to the package.

[0102] 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.

[0103] According to the present disclosure, it is possible to obtain a wiring board, a package, and an optical module that can adjust impedance so that it does not become too large above a desired value.

[0104] The present disclosure can be used as a wiring board, a package, and an optical module.

[0105] 1 wiring substrate 11 first insulating base 111 first upper surface 112 first side surface 113 second upper surface 114 first layer 115 second layer 116 slit 12 second insulating base 121 third upper surface 122 second side surface 123 third side surface 21 first notch portion 21c center of first notch portion 211 first inner wall surface 212 first bottom surface 22 second notch portion 22c center of second notch portion 221 second inner wall surface 222 second bottom surface 23 third notch portion 231 third inner wall surface 232 third bottom surface 24 fourth notch portion 241 fourth inner wall surface 242 fourth bottom surface 25 fifth notch portion 26 sixth notch portion 26c center of sixth notch portion 31 First ground conductor 31c Center of first ground conductor 311 First part 312 Second part 313 First edge 314 Second edge 32 Second ground conductor 32c Center of second ground conductor 321 Third part 322 Fourth part 323 Third edge 324 Fourth edge 33 First signal conductor 331 Part 5 332 Part 6 34 Power supply conductor 341 Part 7 342 Part 8 35 Second signal conductor 351 Part 9 36 Third ground conductor 36c Center of third ground conductor 361 Part 11 41 First ground external terminal 42 Second ground external terminal 43 First signal external terminal 44 Power supply external terminal 47 Other external terminal 51 First inner-layer ground conductor 51c Center of first inner-layer ground conductor 52 Second inner-layer ground conductor 52c Center of second inner-layer ground conductor 53 First via conductor 54 Second via conductor 55 First coated portion 56 Second coated portion 61 Optical module 62 Package 63 Frame 64 Base 65 Cylinder 66 Lid 67 Seal ring 68 Optical element 69 Bonding wire

Claims

1. A wiring board comprising: a first insulating base having a first top surface, a first side surface connected to the first top surface, and a first cutout portion cut out from the first top surface to the first side surface; a first ground conductor having a first portion located on the first top surface and extending from a line overlapping with the first side surface in a planar view, and a second portion located within the first cutout portion and connected to the first portion; and a first signal conductor located on the first top surface alongside the first ground conductor in a first direction, wherein the first portion surrounds at least a portion of the first cutout portion in a planar view, and the distance between the center of the first ground conductor and the first signal conductor on the line overlapping with the first side surface in a planar view is smaller than the distance between the center of the first cutout portion and the first signal conductor.

2. The wiring board according to claim 1, wherein the dimensions of the first ground conductor are larger than the dimensions of the first signal conductor on a line that overlaps with the first side surface in a plan view.

3. A wiring board as described in claim 1 or 2, wherein the first cutout portion has a first inner wall surface connected to the first top surface and a first bottom surface connected to the first inner wall surface, and the second portion is located on the first inner wall surface and the first bottom surface.

4. The wiring board according to any one of claims 1 to 3, wherein the corners of the first cutout portion are arc-shaped in plan view.

5. The wiring board according to any one of claims 1 to 4, further comprising a second ground conductor located on the first upper surface on the opposite side of the first ground conductor with the first signal conductor in between.

6. The wiring board described in claim 5, wherein the first insulating base further comprises a second cutout portion cut out from the first upper surface to the first side surface, and the second ground conductor has a third portion located on the first upper surface and extending from a line overlapping with the first side surface in a planar view, and a fourth portion located within the second cutout portion and connected to the third portion, and the third portion surrounds at least a portion of the second cutout portion in a planar view, and the distance between the center of the second ground conductor and the first signal conductor on the line overlapping with the first side surface in a planar view is smaller than the distance between the center of the second cutout portion and the first signal conductor.

7. The wiring board according to any one of claims 1 to 6, further comprising a power supply conductor located on the first upper surface on the opposite side of the first signal conductor with the first ground conductor in between.

8. A wiring board as claimed in any one of claims 1 to 7, wherein the first insulating base further comprises a third notch portion cut out from the first upper surface to the first side surface, and the first signal conductor has a fifth portion located on the first upper surface and connected to the third notch portion, and a sixth portion located within the third notch portion and connected to the fifth portion.

9. The wiring board according to claim 8, wherein the third cutout portion has a third inner wall surface connected to the first upper surface and a third bottom surface connected to the third inner wall surface, and the third bottom surface is exposed.

10. A wiring board as described in any one of claims 1 to 9, wherein the first insulating base has a first layer having the first upper surface and a second layer located below the first layer, and further comprises a first inner-layer ground conductor located between the first layer and the second layer, and a first via conductor that penetrates the first layer and connects to the first ground conductor and the first inner-layer ground conductor, and in a planar view, the distance between the first via conductor and the first signal conductor is smaller than the distance between the first cutout portion and the first signal conductor.

11. The wiring board according to any one of claims 1 to 10, further comprising a second insulating base positioned on the first upper surface, the first ground conductor, and the first signal conductor.

12. The wiring board according to claim 11, wherein the second insulating base has a third upper surface and a second side surface connected to the third upper surface and in contact with the first upper surface, and further comprises a first coating portion located along the second side surface on the first ground conductor and the first signal conductor.

13. The wiring board according to any one of claims 1 to 12, further comprising: a first external ground terminal electrically connected to the first ground conductor; and a first external signal terminal electrically connected to the first signal conductor.

14. The wiring board according to claim 13, wherein all of the first external ground terminals overlap with the first cutout portion on a line that overlaps with the first side surface in a plan view.

15. The wiring board according to claim 5 or 6, further comprising: a first external ground terminal electrically connected to the first ground conductor; a first external signal terminal electrically connected to the first signal conductor; and a second external ground terminal electrically connected to the second ground conductor, wherein the spacing between the first external ground terminal and the first external signal terminal is the same as the spacing between the second external ground terminal and the first external signal terminal.

16. The wiring board described in any one of claims 1 to 15, wherein the first cutout portion has a first inner wall surface connecting to the first top surface and a first bottom surface connecting to the first inner wall surface, the first insulating base has a first layer having the first top surface and the first inner wall surface and a second layer located below the first layer, the second layer has a second top surface including the first bottom surface, the second portion is located on the first inner wall surface and the first bottom surface, and further comprises a first inner-layer ground conductor located on the second top surface, the first inner-layer ground conductor is connected to the second portion and exposed on the first side surface, and the distance between the center of the first inner-layer ground conductor and the first signal conductor on a line overlapping with the first side surface in a plan view is smaller than the distance between the center of the first cutout portion and the first signal conductor.

17. A package comprising: a wiring board according to any one of claims 1 to 16; and a frame body joined to the wiring board.

18. An optical module comprising: the package according to claim 17; an optical element mounted in said package; and a lid joined to said package.

Images