JP6633979B2 - Waveguide and method of manufacturing waveguide - Google Patents

Description

  The present invention relates to a waveguide and a method for manufacturing the waveguide.

  In recent years, high-speed, large-capacity communication of several gigabits per second (bps) using a millimeter wave band has been proposed, and a part thereof is being realized. In particular, wireless communication devices operating in the 60 [GHz] band are becoming more important. In Japan, a wide frequency band from 59 [GHz] to 66 [GHz] can be used without a license, so that it is expected to spread to the consumer field. In addition, the E-band from 70 [GHz] to 90 [GHz] has attracted attention for the same reason, and there is an urgent need to realize an inexpensive and small-sized millimeter-wave communication module.

  As a mode for realizing a small and inexpensive millimeter-wave communication module, for example, Patent Document 1 proposes a mode converter using a post-wall waveguide (Post-wall Waveguide).

JP 2014-158243 A

  The function of the post-wall waveguide as a waveguide is surrounded by a ground conductor layer (wide wall) formed on both surfaces of the substrate and side walls (narrow wall, short wall) formed by a group of through conductors (posts). This is because a signal (electromagnetic wave) is confined in the inner region (waveguide region). For this reason, it is preferable that the conductor layer in contact with the waveguide region is formed without loss.

  However, in a conventional post-wall waveguide, a group of through conductors (posts) is used for side walls (narrow walls, short walls), and a conductor layer made of metal is formed on all wall surfaces in the through holes. For this reason, there has been a problem that it is very difficult to inspect the state of the conductor layer in contact with the waveguide region (whether or not there is a formation defect) by appearance as an inspection when manufacturing the post wall waveguide. Further, it is very difficult to inspect the state of the conductor layer by conduction because all the through conductors are in contact with the ground conductor layers (wide walls) on the upper and lower surfaces of the substrate.

  As a final product inspection, it is also possible to measure the high-frequency characteristics of the post wall waveguide. However, even if there is a defect in a part of the through conductor at a stage after the production of the post wall waveguide, if the size of the defect is minute, it may be determined to be good in the initial characteristics. . In this case, there is a concern that characteristics may be deteriorated due to aging due to undiscovered defects. For this reason, it is desired that the conductor layer in contact with the waveguide region, in particular, the conductor layer forming the side wall (narrow wall, short wall) can be surely inspected by visual inspection.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a waveguide capable of easily inspecting a conductor layer in a through hole forming a side wall of a waveguide and a method for manufacturing the waveguide. Make it an issue.

In order to solve the above problem, the present invention provides a substrate having a through hole penetrating between one main surface and the other main surface in a region where a side wall surrounding a waveguide region of a waveguide is formed, A first ground conductor layer formed on the one main surface of the substrate, a second ground conductor layer formed on the other main surface of the substrate, and the first ground conductor formed on a wall surface of the through hole; A waveguide comprising a conductor layer and a side wall made of a connection conductor layer connecting the second ground conductor layer, wherein the connection conductor layer is formed on at least the waveguide region of a wall surface of the through hole. The wall surface of the through-hole has a portion protruding toward the outside of the waveguide region, and at least a side of the protruded portion facing the waveguide region has the connection surface. have a region where the conductor layer is omitted, among the wall surface of the through hole, small Side that Kutomo facing the waveguide region, toward the outside of the waveguide region, to provide a waveguide, characterized in that has an internal convex shape of the substrate.

In order to solve the above problem, the present invention provides a substrate having a through hole penetrating between one main surface and the other main surface in a region where a side wall surrounding a waveguide region of a waveguide is formed, A first ground conductor layer formed on the one main surface of the substrate, a second ground conductor layer formed on the other main surface of the substrate, and the first ground conductor formed on a wall surface of the through hole; A waveguide comprising a conductor layer and a side wall made of a connection conductor layer connecting the second ground conductor layer, wherein the connection conductor layer is formed on at least the waveguide region of a wall surface of the through hole. The wall surface of the through-hole has a portion protruding toward the outside of the waveguide region, and at least a side of the protruded portion facing the waveguide region has the connection surface. It has an area where the conductor layer is omitted, among the wall surface of the through hole, before Side in contact with the waveguide region, toward the outside of the waveguide region, to provide a waveguide, characterized in that has an internal convex shape of the substrate.

In order to solve the above problem, the present invention provides a substrate having a through hole penetrating between one main surface and the other main surface in a region where a side wall surrounding a waveguide region of a waveguide is formed, A first ground conductor layer formed on the one main surface of the substrate, a second ground conductor layer formed on the other main surface of the substrate, and the first ground conductor formed on a wall surface of the through hole; A waveguide comprising a conductor layer and a side wall made of a connection conductor layer connecting the second ground conductor layer, wherein the connection conductor layer is formed on at least the waveguide region of a wall surface of the through hole. The wall surface of the through-hole has a portion protruding toward the outside of the waveguide region, and at least a side of the protruded portion facing the waveguide region has the connection surface. It has an area where the conductor layer is omitted, among the wall surface of the through hole, before The position where the side in contact with the waveguide region is most protruded toward the outside of the waveguide region is a position on the side of the one main surface facing the waveguide region, and the opening on the other main surface. A waveguide is provided, wherein the waveguide exists in a direction toward the inside of the waveguide region from a straight line connecting a position on the side facing the waveguide region in the periphery.

  The waveguide is a planar circuit formed on any one of the one main surface or the other main surface of the substrate, and a pin connected to the planar circuit and projecting into the waveguide region, May be provided.

Further, the present invention is the method of manufacturing a waveguide , wherein a portion of the substrate where a side wall surrounding the waveguide region of the waveguide is formed, wherein one main surface and the other main surface of the substrate are provided. Forming a continuous modified portion by laser irradiation on the substrate, and penetrating between the one main surface and the other main surface along the modified portion, A second step of forming a through hole having a portion whose wall surface protrudes toward the outside of the wave region; a first ground conductor layer formed on the one main surface of the substrate; and the other main surface of the substrate. A second ground conductor layer formed on the surface, and a third step of forming a connection conductor layer formed on the wall surface of the through hole and connecting the first ground conductor layer and the second ground conductor layer, Wherein, in the third step, a front surface of at least a side of the wall surface of the through hole that is in contact with the waveguide region is provided. Forming a connection conductor layer, wherein in said projecting portion in the through-holes, to provide a method of manufacturing a waveguide, characterized in that providing the connecting conductor layer is omitted area.

  According to the present invention, since the portion where the wall surface of the through hole protrudes toward the outside of the waveguide region has the region where the connection conductor layer is omitted, the connection in contact with the waveguide region is provided through the omitted region. The state of the conductor layer can be easily inspected by the appearance. Further, since the region where the connection conductor layer is omitted is provided in a portion where the wall surface of the through hole protrudes outward, the region can be easily formed.

It is a perspective view showing a 1st embodiment of a waveguide. FIG. 2 is a sectional view taken along line AA of FIG. 1. It is sectional drawing which shows 2nd Embodiment of a waveguide. It is sectional drawing which shows the state before formation of a conductor layer in 2nd Embodiment. It is sectional drawing which shows 3rd Embodiment of a waveguide. It is sectional drawing which shows 4th Embodiment of a waveguide. It is sectional drawing which shows 5th Embodiment of a waveguide. It is sectional drawing which shows 6th Embodiment of a waveguide.

  Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings.

  FIG. 1 is a perspective view schematically showing the first embodiment of the waveguide. FIG. 2 is a sectional view taken along line AA of FIG. The waveguide 100 of the present embodiment has a waveguide main body 110 and a mode converter 120. Examples of the substrate 101 of the waveguide 100 include a dielectric substrate such as a glass substrate, a sapphire substrate, and a quartz substrate, a semiconductor substrate, a single crystal substrate, and a composite substrate. This waveguide 100 can be used as a high-frequency device through which a high-frequency signal (electromagnetic wave) such as a millimeter wave is propagated.

  As shown in FIG. 2, the substrate 101 has one main surface 101a and the other main surface 101b as surfaces facing each other in the thickness direction. On one main surface 101a of the substrate 101, a first ground conductor layer 111 is formed. On the other main surface 101b of the substrate 101, a second ground conductor layer 112 is formed. These ground conductor layers 111 and 112 are conductor layers such as metal thin films provided on both main surfaces 101a and 101b of the substrate 101. The ground conductor layers 111 and 112 are provided on substantially the entire surface of the substrate 101 except for peripheral regions such as the conductor portion 114, the planar circuit 122, and the pins 123. The ground conductor layers 111 and 112 are connected to a ground potential (not shown).

  The waveguide main body 110 has a configuration in which the waveguide region 102 of the substrate 101 is surrounded by ground conductor layers 111 and 112 and side walls 113 (connection conductor layers 116). Since the periphery of the waveguide region 102 is surrounded by the conductor layer, the waveguide region 102 functions as a path through which a high-frequency signal propagates.

  The side wall 113 is a structure that surrounds the waveguide region 102 in the plane of the substrate 101. FIG. 2 shows the structure of two narrow walls 113A, 113A facing each other in the direction of the line AA in FIG. 1, that is, in the width direction of the waveguide main body 110, among the side walls 113 of the waveguide. The side wall 113 is not limited to the narrow wall 113A, and the short wall 113B provided at the end in the longitudinal direction of the waveguide main body 110 can also be formed of the same row of the conductor portions 114 as the narrow wall 113A.

  The shape of the conductor portion 114 forming the narrow wall 113A or the short wall 113B is not limited to a conductor pillar (post) having a columnar shape as shown in FIG. For example, a conductor portion 114 having a shape continuous along the wall surfaces of the narrow wall 113A and the short wall 113B, a conductor portion 114 having a shape continuous along a corner portion of the narrow wall 113A and the short wall 113B, and the like can be employed. .

  When using a wall-shaped conductor in which part or all of the narrow wall 113A is continuous along the longitudinal direction of the waveguide main body 110, since the side wall in the direction in which the electromagnetic wave travels becomes a continuous wall, it is possible to suppress disturbance of the electromagnetic wave form. Can be. In this case, even when the substrate 101 has the continuous conductor portion 114, it is preferable that the substrate material inside and outside the conductor portion 114 is not separated. For example, a portion where the conductor portion 114 is discontinuous can be provided on a part of the narrow wall 113A or the short wall 113B. Specifically, the short wall 113B is formed of a conductor pillar, or a conductor pillar for dividing a continuous conductor portion is provided at a corner between the narrow wall 113A and the short wall 113B or at a part of the narrow wall 113A. Or the like.

  A mode converter 120, an opening 130 through which a high-frequency signal is radiated to the outside, and the like can be provided at the longitudinal end of the waveguide body 110.

FIG. 1 shows an example in which the short wall 113B serving as the rear wall of the pin 123 is composed of a plurality of conductor columns. However, the configuration of the side wall 113 around the mode converter 120 is not limited to the example of FIG. For example, by forming the narrow walls 113A, 113A on the sides of the pin 123 from a continuous wall-shaped conductor, leakage of electromagnetic waves can be effectively prevented as compared with the conductor pillar.
Further, three sides of the two narrow walls 113A, 113A and the short wall 113B around the mode converter 120 may be formed of a continuous wall-shaped conductor. In this case, since the periphery of the pin 123 is a closed space, leakage of electromagnetic waves can be suppressed. It is also possible to configure the three sides from one continuous wall-shaped conductor. It is also possible to form a wall-shaped conductor that is continuous for each side (discontinuous between the sides).

  FIG. 1 shows an example in which two narrow walls 113A, 113A are arranged in parallel toward the opening 130, but the portions 131, 131 of the narrow walls 113A, 113A on the opening 130 side are connected to the opening 130. It is also possible to adopt a configuration in which the interval (the width of the waveguide region 102) increases toward it. In this case, an H-plane fan type horn antenna can be configured, and the antenna gain can be improved.

  The mode converter 120 shown in FIG. 1 includes a planar circuit 122 formed on any surface of the substrate 101, and a pin 123 connected to the planar circuit 122 and protruding into the waveguide region 102 of the substrate 101. Having. The planar circuit 122 is separated from the ground conductor layers 111 and 112 via a gap. By radiating the signal propagated from the planar circuit 122 from the pin 123 to the waveguide region 102, the signal can be propagated from the planar circuit 122 to the waveguide main body 110. Further, the signal transmitted from the waveguide main body 110 is received by the pin 123, so that the signal can be transmitted from the waveguide main body 110 to the planar circuit 122.

  The opening 130 is a region where the side wall 113 is eliminated at the longitudinal end of the waveguide main body 110. Since no conductive layer is formed between the waveguide region 102 between the narrow walls 113A and 113A and the side surface of the substrate 101, a high-frequency signal propagates between the waveguide region 102 and the outside of the substrate 101. Functions as a route.

  The conductor portion 114 shown in FIGS. 1 and 2 has a structure in which a connection conductor layer 116 is formed on a wall surface of a through hole 115 formed in the substrate 101. The through hole 115 penetrates between one main surface 101a and the other main surface 101b. The connection conductor layer 116 connects the first ground conductor layer 111 and the second ground conductor layer 112. Therefore, the connection conductor layer 116 is connected to a ground potential (not shown) through the ground conductor layers 111 and 112. Similar to the planar shape of the conductor portion 114, the planar shape of the through hole 115 is not particularly limited, and may be a circular hole, a long hole, a slit continuous over a predetermined section, or the like.

  The substrate 101 has a row of through holes 115 in a region where the side wall 113 of the waveguide main body 110 is formed. The direction in which the rows of the through holes 115 are arranged is along the direction in which the side wall 113 extends. The side walls 113 of the waveguide main body 110 are constituted by the rows of the connection conductor layers 116 formed in the respective through holes 115. The interval when the conductor portion 114 is formed discontinuously is set so that the high-frequency signal does not leak outside the waveguide region 102. The parameters to be considered when setting the interval between the conductors 114 include the wavelength of the high-frequency signal, the dielectric constant of the dielectric constituting the substrate 101, the size of the through-hole 115, and the like.

  As shown in FIG. 2, the connection conductor layer 116 is formed on at least the side of the wall surface of each through hole 115 that contacts the waveguide region 102. Further, the wall surface of each through hole 115 has a protruding portion 117 having a shape protruding toward the outside of the waveguide region 102. The protruding portion 117 is a portion in which at least the side facing the waveguide region 102 of the wall surface of each through hole 115 has a convex shape inside the substrate 101 toward the outside of the waveguide region 102.

  In this specification, the outside of the waveguide region 102 is a direction from the inside of the waveguide region 102 to the outside, and the inside of the waveguide region 102 is a direction from the outside of the waveguide region 102 to the inside. . The concepts of outside and inside with reference to the waveguide region 102 are preferably applied in a plane perpendicular to the thickness direction of the substrate 101 or in the main surface direction of the substrate 101 (direction parallel to the main surfaces 101a and 101b). You.

The conductor portion 114 has a region where the connection conductor layer 116 is omitted in the protruding portion 117. Accordingly, only the internal space (dielectric) of the transparent substrate 101 and the through hole 115 is interposed between the side surface 103 of the substrate 101 and the connection conductor layer 116 in contact with the waveguide region 102. Therefore, the state of the connection conductor layer 116 can be visually inspected from the side surface 103 of the substrate 101.
Note that in this specification, “omission” and “deletion” both mean partial absence of the connection conductor layer 116 or insufficient thickness, but “deletion” is not intended. On the other hand, “omission” means a case where the design is provided in a sufficient range for the appearance inspection.

  In general, the connection conductor layer 116 is formed by supplying a conductor into each of the openings 115a of the through-hole 115, so that the connection conductor layer 116 is likely to be damaged near the center of the substrate 101 in the thickness direction. Therefore, it is preferable that the region where the connection conductor layer 116 is omitted on the side facing the waveguide region 102 be provided inside the substrate 101 (in the vicinity of the center in the thickness direction) of the through hole 115.

  Of the wall surface of the through hole 115, at the opening end 115 c near each opening 115 a, even if the connection conductor layer 116 is formed over the entire circumference from the side in contact with the waveguide region 102 to the side facing the waveguide region 102. Good. According to the present embodiment, the quality determination of the connection conductor layer 116 by the appearance inspection can be performed sufficiently effectively.

  Further, when depositing the conductor forming the connection conductor layer 116 on the wall surface of the through hole 115 through the opening 115 a of the through hole 115, the conductor does not easily adhere to the protruding portion 117. By forming the protruding portion 117 in the through-hole 115 before forming the connection conductor layer 116, it is possible to easily form a region in the protruding portion 117 where the connection conductor layer 116 is omitted.

  As shown in FIG. 2, the side of the wall surface of each through-hole 115 that contacts the waveguide region 102 may be substantially perpendicular to both main surfaces 101 a and 101 b of the substrate 101. In this case, the thickness of the through hole 115 may be larger at the protruding portion 117 than at the opening 115a.

  FIG. 3 shows a schematic structure of a waveguide 100A of the second embodiment. In the present embodiment, the side of the wall surface of each through hole 115 that contacts the waveguide region 102 has a convex shape inside the substrate 101 toward the outside of the waveguide region 102. Each through-hole 115 in the present embodiment has a structure in which a portion inclined from the opening 115a on the one main surface 101a side and a portion inclined from the opening 115a on the other main surface 101b communicate with each other inside the substrate 101. It has a bent portion 115b. The thickness of the through hole 115 may be substantially equal between the bent portion 115b and the opening 115a.

  The conductor portion 114A forming the side wall in the waveguide 100A of the present embodiment has a region where the connection conductor layer 116 is omitted at least in the bent portion 115b on the side facing the waveguide region 102. Thereby, the quality determination of the connection conductor layer 116 by the appearance inspection can be performed sufficiently effectively.

  The bent portion 115b has an effect of making it easier to form a region where the connection conductor layer 116 is omitted, on the side facing the waveguide region 102, as in the case of the protruding portion 117 of the first embodiment. Further, according to the present embodiment, when a part (such as a seed layer) of the connection conductor layer 116 is formed by highly anisotropic sputtering or the like, the side in contact with the waveguide region 102 is closer to the opening 115 a of the through hole 115. This is preferable because the connection conductor layer 116 with few defects can be easily obtained from the substrate 101 to the inside of the substrate 101.

  Of the wall surface of the through hole 115, at the opening end 115 c near each opening 115 a, even if the connection conductor layer 116 is formed over the entire circumference from the side in contact with the waveguide region 102 to the side facing the waveguide region 102. Good. Even if the connection conductor layer 116 is formed on the side facing the waveguide region 102 at the open end 115c, the bent portion 115b inside the substrate 101 has a region where the connection conductor layer 116 is omitted. The quality of the connection conductor layer 116 can be determined sufficiently effectively.

FIG. 4 shows the substrate 101 before forming each conductor layer (the ground conductor layers 111 and 112 and the connection conductor layer 116) when manufacturing the waveguide 100A shown in FIG.
In each through hole 115 formed in the substrate 101, a position 115p indicates a position where the wall surface of the through hole 115 in contact with the waveguide region 102 protrudes most outside the waveguide region 102. The position 115i indicates a position on the side of the periphery of the opening 115a on one main surface 101a that faces the waveguide region 102. The position 115j indicates a position on the side of the periphery of the opening 115a in the other main surface 101b that faces the waveguide region 102. The straight line B is a vertical line passing through the position 115p (a line perpendicular to the main surfaces 101a and 101b). The straight line C is a straight line connecting the position 115i and the position 115j.

  As shown in FIG. 4, the position 115 p on the straight line B where the wall surface of the through-hole 115 is most protruded exists in the direction from the outside of the waveguide region 102 to the inside of the straight line C. That is, the straight line B passes through the inside of each opening 115a in both main surfaces 101a and 101b. In addition, the straight line C does not intersect with a line along the side 115q in contact with the waveguide region 102 in the wall surface of each through hole 115. According to such a configuration, when a conductor is deposited on the wall surface of the through-hole 115 by sputtering or the like, the position 115p that protrudes most on the side that contacts the waveguide region 102 is positioned at the opening end 115c (particularly near the positions 115i and 115j This is preferable because the conductor easily reaches the position 115p where the conductor projects most, and the connection conductor layer 116 on the side in contact with the waveguide region 102 is less likely to be damaged.

  Next, an example of a method for manufacturing the waveguides 100 and 100A of the first and second embodiments will be described. Note that this manufacturing method is also applicable to waveguides 100B, 100C, 100D, and 100E of third to sixth embodiments described later. Here, the case where the waveguides 100 and 100A have the waveguide main body 110 and the mode converter 120 as shown in FIG. 1 will be described as an example, and the manufacturing process of the mode converter 120 will also be described.

  First, as a first step, a modified portion is formed from the one main surface 101a or the other main surface 101b of the substrate 101 to a desired depth by irradiating the substrate 101 with laser light. The modified portion is a portion in which a dielectric material such as glass or resin constituting the substrate 101 is modified by laser light. As the laser light, an ultrashort pulse laser having a pulse width of 10 ps or less is preferable, for example, a femtosecond laser having a pulse width of about 250 fs.

  The position where the modified portion is formed can be changed to an arbitrary position and direction in the thickness direction and main surface direction of the substrate 101 by condensing and irradiating the laser beam and scanning the focal point. The dimensions (length, thickness) of the modified portion can be controlled by the laser irradiation conditions (focus size, scanning distance). When the thickness of the modified portion is large, the focal position may be scanned so that the laser beam irradiates the same position or its vicinity twice or more.

  When a continuous modified portion is formed between one main surface 101a of the substrate 101 and the other main surface 101b, a scanning method is not particularly limited. The modified portion formed from one main surface 101a and the modified portion formed from the other main surface 101b may be connected inside the substrate 101. Further, the scanning may be continued from one main surface 101a to the other main surface 101b or from the other main surface 101b to the one main surface 101a to form the reformed portion at one time.

  Next, as a second step, a through hole is formed along the modified portion formed on the substrate 101 in the first step. Since the modified portion has higher solubility than the non-modified portion (non-modified portion), the modified portion can be removed preferentially or selectively by etching or the like. When forming the through-hole in the modified portion, it is not particularly limited whether a part of the non-reformed portion is removed at a lower speed than the modified portion or only the modified portion is removed.

  The solvent (etchant) used for removing the modified portion can be appropriately selected depending on the material of the substrate 101. For example, when the material of the substrate 101 is glass containing Si (quartz glass, borosilicate glass, silicate glass, or the like), hydrofluoric acid (HF) is used as an etchant.

  The etching step can be performed by immersing the substrate 101 having the modified portion in a chemical solution containing an etchant. As a result, the modified portion is wet-etched from the main surfaces 101a and 101b of the substrate 101 with a chemical solution and removed from the substrate 101. When the reformed portion is removed from between the two main surfaces 101a and 101b, a through hole 115 penetrating between one main surface 101a and the other main surface 101b is formed.

  Next, as a third step, conductor layers (the ground conductor layers 111 and 112 and the connection conductor layer 116) are formed on the substrate 101 on which the through holes 115 are formed.

  As a method of forming the connection conductor layer 116, one or more of sputtering, vacuum deposition, plating, and the like can be given. After a seed layer of Cr, Ti, or the like is formed by sputtering, vacuum deposition, or the like on the wall surface of the through-hole 115 (dielectric constituting the substrate 101), electrolytic plating, electroless plating, or the like is formed on the seed layer. It is preferable to stack a conductor layer of Cu or the like because the adhesion to the substrate 101 is high and the connection conductor layer 116 with few defects can be easily obtained.

  The ground conductor layers 111 and 112 can be formed in the same manner as the connection conductor layer 116. The ground conductor layers 111 and 112 and the connection conductor layer 116 can be formed simultaneously (in parallel). When the ground conductor layers 111 and 112 and the connection conductor layer 116 are formed of different materials, the main surfaces 101a and 101b of the substrate 101 or the wall surfaces of the through holes 115 are covered with a coating layer such as a resist, and the portions without the coating layer are covered. The conductors may be deposited to form the ground conductor layers 111 and 112 or the connection conductor layer 116 at different times.

  The method of forming the planar circuit 122 and the pins 123 can be the same as the method of forming the ground conductor layers 111 and 112 and the connection conductor layer 116. When the pins 123 are formed in the same manner as the connection conductor layer 116, in the first step, a modified portion is formed from the main surfaces 101a, 101b to a point in the thickness direction of the substrate 101, and in the second step, the substrate 101 is formed. A hole that does not penetrate (fine hole) may be formed, and a conductor may be deposited inside the hole that does not penetrate the substrate 101 in the third step.

Further, as a fourth step, a step of inspecting the state of the connection conductor layer 116 formed in the third step from outside the substrate 101 can be provided. Since the waveguide of each embodiment manufactured through the first step to the third step has a region where the connection conductor layer 116 is omitted on the side of the wall surface of the through hole 115 facing the waveguide region 102. In addition, the quality of the connection conductor layer 116 can be effectively determined by the appearance inspection. For example, in the case where all or most of the connection conductor layers 116 are missing inside one or two or more through holes 115 among the plurality of connection conductor layers 116 forming the side wall 113, or when the connection conductor layers 116 By judging a case where it is lifted from the wall surface of the through-hole 115 as a defective product, it is possible to more reliably eliminate a defect that is hardly found in the characteristic inspection after the completion of the waveguide.
Since the inspection in the fourth step can be performed without propagating the signal to the waveguide, it can be performed before the configuration for inputting the signal to the waveguide through the signal input unit of the mode converter 120 or the like is completed. it can.

  Next, FIG. 5 shows a schematic structure of a waveguide 100B of the third embodiment. The conductor 114B of the present embodiment has substantially the same structure as the conductor 114A of the second embodiment. However, in the present embodiment, of the wall surface of the through-hole 115, an opening end 115c near each opening 115a is substantially perpendicular to both main surfaces 101a and 101b of the substrate 101.

  The connection conductor layer 116 may be formed on the entire opening from the side in contact with the waveguide region 102 to the side facing the waveguide region 102 at the open end 115c. Since the bent portion 115b near the center in the thickness direction has a region where the connection conductor layer 116 is omitted, the quality of the connection conductor layer 116 can be sufficiently and effectively determined by an appearance inspection.

  Further, when the waveguide 100B of the present embodiment is compared with the waveguide 100A of the second embodiment, the through-hole 115 is substantially perpendicular to both the main surfaces 101a and 101b at the opening end 115c near the opening 115a. The position accuracy of the opening 115a can be improved, and a product having stable characteristics can be easily manufactured.

  Next, FIG. 6 shows a schematic structure of a waveguide 100C of the fourth embodiment. The conductor 114C of the present embodiment has substantially the same structure as the conductor 114A of the second embodiment. However, in the present embodiment, the shape of the wall surface of the through-hole 115 protruding outside the waveguide region 102 is a curved portion 115d that is smoothly curved. The opening end 115c may be substantially perpendicular to both main surfaces 101a and 101b of the substrate 101 as in the third embodiment, or may be inclined as in the second embodiment.

  In addition, the connection conductor layer 116 may be formed on the open end 115c over the entire circumference from the side contacting the waveguide region 102 to the side facing the waveguide region 102. In the curved portion 115d inside the substrate 101, there is a region where the connection conductor layer 116 is omitted, so that the quality judgment of the connection conductor layer 116 by the appearance inspection can be performed sufficiently effectively.

  In addition, when the waveguide 100C of the present embodiment is compared with the waveguides 100A and 100B of the second and third embodiments, since the wall surface of the through-hole 115 changes smoothly inside the substrate 101, The stress of the material of the substrate 101 and the connection conductor layer 116 in the vicinity of the wall surface of 115 is further reduced, and the reliability over time is expected.

  Next, FIG. 7 shows a schematic structure of a waveguide 100D of the fifth embodiment. In the present embodiment, a resin layer 118 is formed on each of the main surfaces 101a and 101b of the substrate 101. In this case, since the inside of the through-hole 115 is filled with air (gas), the quality of the connection conductor layer 116 can be sufficiently effectively determined by the appearance inspection. Two or more resin layers 118 may be stacked. The resin forming the resin layer 118 may be an electrical insulator, and may be colorless, transparent, or colored.

  Furthermore, when the opening 115 a of the through hole 115 is closed by the resin layer 118, it is possible to prevent foreign substances from entering the inside of the through hole 115. The resin layer 118 may be open above the opening 115 a of the through hole 115. The method for forming the resin layer 118 is not particularly limited, and includes a method of applying a liquid resin on the main surfaces 101a and 101b and then curing the resin, a method of bonding a sheet-like resin to the substrate 101, and the like. .

  Next, FIG. 8 shows a schematic structure of a waveguide 100E of the sixth embodiment. This embodiment can be the same as the fifth embodiment except that the inside of the through hole 115 in FIG. 7 is filled with the transparent resin 119. In the case of the sixth embodiment, since the difference in the refractive index between the substrate 101 and the transparent resin 119 can be reduced to suppress the reflection and refraction of light, the quality of the connection conductor layer 116 can be sufficiently effectively determined by an appearance inspection. . The transparent resin 119 may be any resin that transmits light.

The resin layer 118 and the transparent resin 119 may be the same transparent resin. Further, by performing the step of laminating the resin layer 118 on the main surfaces 101a and 101b and the step of filling the through-hole 115 with the transparent resin 119 at a time, the number of steps can be reduced.
Further, the transparent resin 119 and the resin layer 118 may be different resins, such as selecting a resin suitable for filling the fine holes as the transparent resin 119 and selecting a resin having excellent leveling properties as the resin layer 118. .

  Although FIGS. 7 and 8 illustrate the case where the structure of the conductor portion 114A is the same as that of the second embodiment, the structure may be the same as the conductor portions 114, 114B and 114C of other embodiments.

  As described above, the present invention has been described based on the preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention.

  The portion where the wall surface of the through hole 115 protrudes toward the outside of the waveguide region 102 is, in the circumferential direction of the through hole 115, a side in contact with the waveguide region 102, a side facing the waveguide region 102, an intermediate portion thereof, and the like. It may be present in any one or two or more regions, and may be present all around the through hole 115.

  On the side of the through-hole 115 facing the waveguide region 102, the portion where the opening end 115 c protrudes in the direction approaching the waveguide region 102 is cut off after the formation of the connection conductor layer 116 and the omitted portion thereof. Is also good.

  At least on the side of the wall surface of the through-hole 115 that is in contact with the waveguide region 102, the connection conductor layer 116 is preferably formed continuously from one main surface 101a to the other main surface 101b, A slight defect may occur to the extent that the characteristics of the waveguide are not hindered. For example, a defect that is sufficiently small (short) compared to the wavelength of a signal (electromagnetic wave) propagated through the waveguide and cannot be detected by ordinary visual inspection usually does not affect the characteristics of the waveguide. For example, it is not necessary to consider practically the presence or absence of a microscopic defect that is finally found by an electron microscope.

  It is preferable that the connection conductor layer 116 is not formed on the wall surface of the through-hole 115 at least in a region of the wall surface of the through-hole 115 where the connection conductor layer 116 is omitted, at least on a side facing the waveguide region 102. A small amount of conductor may be adhered to the extent that the inspection of the connection conductor layer 116 is not hindered.

  When the state of the connection conductor layer 116 inside the through hole 115 is visually inspected through the substrate 101, it is preferable that the substrate 101 is transparent in the visible light wavelength region, because the visual observation becomes possible. However, even when the substrate 101 is not transparent with respect to visible light, if the dielectric constituting the substrate 101 and the conductor (metal) constituting the connection conductor layer 116 can be distinguished, electromagnetic waves such as infrared light and ultraviolet light, and sound waves It is possible to observe and inspect the state of the connection conductor layer 116 from outside the substrate 101 by using an elastic wave such as an ultrasonic wave.

  The inside of the through hole 115 is not limited to air or the transparent resin 119, and may include a transparent material (solid, liquid, gas, or mixture).

100, 100A, 100B, 100C, 100D, 100E: waveguide, 101: substrate, 101a: one main surface, 101b: other main surface, 102: waveguide region, 110: waveguide body, 111: first ground Conductor layer, 112: second ground conductor layer, 113: side wall, 114, 114A, 114B, 114C: conductor portion, 115: through hole, 115a: opening, 116: connection conductor layer, 117: projecting portion, 120: mode conversion Container, 122: planar circuit, 123: pin.

Claims (6)

A substrate having a through hole penetrating between one main surface and the other main surface in a region where a side wall surrounding a waveguide region of the waveguide is formed,
A first ground conductor layer formed on the one main surface of the substrate;
A second ground conductor layer formed on the other main surface of the substrate;
A side wall formed on a wall surface of the through hole and formed of a connection conductor layer connecting the first ground conductor layer and the second ground conductor layer;
A waveguide comprising:
The connection conductor layer is formed at least on a side of the wall surface of the through hole that contacts the waveguide region,
The wall surface of the through-hole has a portion protruding toward the outside of the waveguide region, and of the protruded portion, at least on a side facing the waveguide region, a region where the connection conductor layer is omitted. have a, of the wall surface of the through hole, waveguide side facing at least the waveguide region, toward the outside of the waveguide region, characterized in that has a convex shape within said substrate . A substrate having a through hole penetrating between one main surface and the other main surface in a region where a side wall surrounding a waveguide region of the waveguide is formed,
A first ground conductor layer formed on the one main surface of the substrate;
A second ground conductor layer formed on the other main surface of the substrate;
A side wall formed on a wall surface of the through hole and formed of a connection conductor layer connecting the first ground conductor layer and the second ground conductor layer;
A waveguide comprising:
The connection conductor layer is formed at least on a side of the wall surface of the through hole that contacts the waveguide region,
The wall surface of the through-hole has a portion protruding toward the outside of the waveguide region, and of the protruded portion, at least on a side facing the waveguide region, a region where the connection conductor layer is omitted. the a, of the wall surface of the through hole, the side in contact with the waveguide region, toward the outside of the waveguide region, waveguides, characterized in that has a convex shape within said substrate. A substrate having a through hole penetrating between one main surface and the other main surface in a region where a side wall surrounding a waveguide region of the waveguide is formed,
A first ground conductor layer formed on the one main surface of the substrate;
A second ground conductor layer formed on the other main surface of the substrate;
A side wall formed on a wall surface of the through hole and formed of a connection conductor layer connecting the first ground conductor layer and the second ground conductor layer;
A waveguide comprising:
The connection conductor layer is formed at least on a side of the wall surface of the through hole that contacts the waveguide region,
The wall surface of the through hole has a portion protruding toward the outside of the waveguide region, and a region where the connection conductor layer is omitted at least on the side of the protruding portion facing the waveguide region. A position where the side of the wall surface of the through-hole, which is in contact with the waveguide region, most protrudes toward the outside of the waveguide region, is opposed to the waveguide region in the opening periphery of the one main surface. And a direction inward of the waveguide region from a straight line connecting the position on the side of the other main surface and the position on the side facing the waveguide region on the periphery of the opening on the other main surface. Waveguide . 4. The wall according to claim 2 , wherein at least a side of the wall surface of the through hole facing the waveguide region has a convex shape inside the substrate toward the outside of the waveguide region. The described waveguide.   A mode comprising at least a planar circuit formed on one of the one main surface and the other main surface of the substrate, and a pin connected to the planar circuit and protruding into the waveguide region. The waveguide according to any one of claims 1 to 4, further comprising a converter. It is a manufacturing method of the waveguide as described in any one of Claims 1-5, Comprising:
In the region of the substrate where the side wall surrounding the waveguide region of the waveguide is formed, a modified portion continuous between one main surface and the other main surface of the substrate is formed by laser irradiation on the substrate. The first step to
A second step of forming a through hole having a portion that penetrates between the one main surface and the other main surface along the modified portion and has a wall surface protruding toward the outside of the waveguide region. When,
A first ground conductor layer formed on the one main surface of the substrate, a second ground conductor layer formed on the other main surface of the substrate, and the first ground conductor layer formed on a wall surface of the through hole; A third step of forming a ground conductor layer and a connection conductor layer that connects the second ground conductor layer;
With
In the third step, in the wall surface of the through hole, the connection conductor layer is formed at least on a side in contact with the waveguide region, and in the protruding portion of the through hole, the connection conductor layer is omitted. A method for manufacturing a waveguide.

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