JP2010080730A - Circuit board and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board and an electronic apparatus wherein an electric signal can be efficiently transmitted in a junction part of coaxial connectors. <P>SOLUTION: The circuit board includes: a substrate including a line conductor 2 which is made of a dielectric and is formed in an inner layer or on a lower principal surface, a center conductor connection part 2b formed on an upper principal surface, an outer peripheral conductor connection part formed around the center conductor connection part, and a via conductor 2a for line which is provided in the dielectric and is electrically connected to the line conductor 2 and the center conductor connection part; and a coaxial connector 3 comprising a cylindrical outer peripheral conductor 3a, a center conductor 3b installed on a center axis of the outer peripheral conductor 3a, and an insulator 3c interposed between them. One end surface of the center conductor 3b of the coaxial connector 3 is electrically and mechanically connected to the center conductor connection part 2b, and one end surface of the outer peripheral conductor 3a of the coaxial connector 3 is electrically and mechanically connected to an outer peripheral conductor connection part 4a of the substrate 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circuit board and an electronic device for operating electronic components.

  Some conventional circuit boards that transmit high-frequency signals include a coaxial connector at one end of a line conductor.

As such a circuit board, for example, there is one in which a through hole is formed at the end of a strip line that functions as a line conductor, and the end of the center conductor of the coaxial connector is inserted and fixed in the through hole. (For example, refer to Patent Document 1 below).
JP 2001-102747 A

  However, since the center conductor of the coaxial connector is inserted into the through hole, the impedance value changes depending on the joining state of the center conductor into the through hole such as the length of the center conductor inserted into the through hole. Therefore, it is difficult to match the impedance value to a constant value. In particular, recently, the control of the bonding state for making the impedance value constant tends to be important due to the high frequency of the electric signal.

  For this reason, there is a problem in that transmission loss such as reflection loss occurs at the portion where the central conductor of the coaxial connector is inserted into the through hole, and the electric signal cannot be transmitted efficiently.

  Accordingly, the present invention has been completed in view of the above problems, and an object of the present invention is to provide a circuit board and an electronic device that can efficiently transmit an electric signal at a joint portion of a coaxial connector.

  The circuit board of the present invention comprises a dielectric, a line conductor formed on the inner layer or the lower main surface, a center conductor connecting portion formed on the upper main surface, and an outer periphery formed around the central conductor connecting portion. A base body having a conductor connecting portion and a line via conductor provided inside the dielectric and electrically connected to the line conductor and the central conductor connecting portion; a cylindrical outer conductor; and the outer conductor A central conductor installed on the central axis and a coaxial connector made of an insulator interposed therebetween, and one end surface of the central conductor of the coaxial connector is electrically and mechanically joined to the central conductor connecting portion. In addition, one end face of the outer peripheral conductor of the coaxial connector is electrically and mechanically joined to the outer peripheral conductor connecting portion.

  In the circuit board according to the present invention, preferably, the center conductor connecting portion is larger than a cross section of the center conductor.

  In the circuit board of the present invention, it is preferable that a gap is provided between the base and the insulator of the coaxial connector.

  In the circuit board of the present invention, it is preferable that a support portion for supporting the outer periphery of the outer peripheral conductor of the coaxial connector is provided on the upper main surface of the base.

  In the circuit board of the present invention, preferably, an upper ground conductor is formed on the upper main surface of the base body, and the outer peripheral conductor connecting portion is connected to the upper ground conductor.

  In the circuit board of the present invention, preferably, a lower ground conductor is formed on the lower main surface of the base, and the upper ground conductor and the lower ground conductor are connected via a ground via conductor. It is characterized by.

  In the circuit board of the present invention, preferably, the base is made of ceramics.

  In the circuit board of the present invention, preferably, the upper main surface of the base is formed with a recess for accommodating an electronic component, and the central conductor connecting portion and the outer peripheral conductor connecting portion are provided outside the recess, and A coaxial connector is joined, and the line conductor is led out inside the recess.

  An electronic device according to the present invention includes a circuit board configured as described above, an electronic component that is housed in the recess and is electrically connected to the line conductor, and a lid that is joined to the upper surface of the recess so as to close the recess. And a body.

  The circuit board of the present invention comprises a dielectric, a line conductor formed on the inner layer or the lower main surface, a center conductor connecting portion formed on the upper main surface, and an outer periphery formed around the central conductor connecting portion. A base body having a conductor connecting portion and a line via conductor provided inside the dielectric and electrically connected to the line conductor and the central conductor connecting portion; a cylindrical outer conductor; and the outer conductor A central conductor installed on the central axis and a coaxial connector made of an insulator interposed therebetween, and one end surface of the central conductor of the coaxial connector is electrically and mechanically joined to the central conductor connecting portion. In addition, since one end surface of the outer peripheral conductor of the coaxial connector is electrically and mechanically joined to the outer peripheral conductor connecting portion, it is brought into contact with the central conductor connecting portion provided on the upper main surface of the substrate. That Thus, it is possible to determine the axial position of the center conductor. In addition, it is not necessary to insert the center conductor into the through hole and join as in the conventional case, and the thickness of the center conductor and the via conductor for the line can be optimized. It can be easily aligned.

  In the circuit board of the present invention, preferably, the central conductor connecting portion is larger than a cross section of the central conductor, so that a meniscus of a conductive adhesive extending from one end surface of the central conductor toward the central conductor connecting portion is formed. The one end face of the center conductor and the center conductor connecting portion can be firmly joined.

  In this circuit board, preferably, since a gap is provided between the base body and the insulator of the coaxial connector, a region having a low dielectric constant is disposed between the base body and the insulator of the coaxial connector. As a result, the capacitance component generated between the central conductor and the outer peripheral conductor is reduced, and the impedance value is higher than a predetermined impedance value in this region. On the other hand, the center conductor connection part is larger than the cross section of the center conductor, and the capacitance component generated between the center conductor connection part and the outer conductor connection part becomes large, and the impedance value at the position of the center conductor connection part is a predetermined impedance. Smaller than the value. Therefore, the high impedance value and the low impedance value are canceled out, and the impedance values at the gap portion and the central conductor connection portion are matched to a predetermined value. As a result, transmission loss due to reflection loss of an electrical signal transmitted through the central conductor can be suppressed.

  In the circuit board of the present invention, it is preferable that a support portion for supporting the outer periphery of the outer peripheral conductor of the coaxial connector is provided on the upper main surface of the base, so that it is coaxial with a predetermined position on the upper main surface of the base. A connector can be installed to support the coaxial connector. That is, the work of electrically and mechanically joining one end face of the center conductor to a predetermined position of the center conductor connecting portion and one end face of the outer conductor to a predetermined position of the outer conductor connecting section can be facilitated. The impedance value of the electric signal can be easily matched with a predetermined value. As a result, the circuit board can be manufactured with good workability, and transmission loss of an electric signal transmitted through the central conductor can be further suppressed.

  In the circuit board of the present invention, preferably, an upper ground conductor is formed, and since the outer conductor connection portion is connected to the upper ground conductor, the ground potential of the outer conductor connection portion is strengthened and stable. It can be. The upper ground conductor can also function as a ground potential conductor for the line conductor. As a result, an electric signal can be transmitted to the center conductor and the line conductor.

  In the circuit board of the present invention, preferably, a lower ground conductor is formed on the lower main surface of the base, and the upper ground conductor and the lower ground conductor are connected via a ground via conductor. Thus, the electrical signal transmitted through the line via conductor can be grounded by the ground via conductor. Therefore, it is possible to efficiently transmit the electric signal transmitted through the line via conductor. Further, the upper ground conductor and the lower ground conductor can be set to the same potential, and impedance matching can be facilitated.

  In the circuit board of the present invention, preferably, since the base is made of ceramics, the circuit board can withstand use in a high-temperature atmosphere.

  In the circuit board of the present invention, preferably, the upper main surface of the base is formed with a recess for accommodating an electronic component, and the central conductor connecting portion and the outer peripheral conductor connecting portion are provided outside the recess, and Since a coaxial connector is joined and the line conductor is led out inside the recess, the coaxial connector can be attached with a simple structure, and a circuit board capable of hermetically sealing electronic components is provided. Can do.

  An electronic device according to the present invention includes the circuit board according to the present invention, an electronic component that is housed in the recess and is electrically connected to a distal end portion of the line conductor, and the upper surface of the recess closes the recess. Since the lid is joined, an electronic device that can efficiently transmit an electrical signal using the circuit board of the present invention can be obtained.

  The circuit board of the present invention will be described in detail below.

  1A is a cross-sectional view showing an example of an embodiment of the circuit board of the present invention, FIG. 1B is a cross-sectional view of another example of the embodiment of the circuit board of the present invention, and FIG. FIG. 2 is a plan view showing an upper main surface of a substrate with respect to the circuit boards of FIG. 1A and FIG. 2A is a cross-sectional view showing another example of the embodiment of the circuit board of the present invention, and FIG. 2B is a plan view showing the upper main surface of the substrate with respect to the circuit board of FIG. It is. FIG. 3A is a cross-sectional view showing another example of the embodiment of the circuit board of the present invention, and FIGS. 3B and 3C show the substrate of the circuit board of FIG. It is a top view which shows the upper main surface.

  4A is a cross-sectional view illustrating an example of an embodiment of a circuit board and an electronic device according to the present invention, and FIG. 4B is a cross-sectional view illustrating another example of an embodiment of the circuit board and the electronic device according to the present invention. FIG.

  In these drawings, 1 is a base, 1a is a recess, 1b is a placement portion, 1c is a side wall portion, 2 is a line conductor, 2a is a line via conductor, 2b is a central conductor connection portion, 2c is a tip portion, Coaxial connector, 3a is outer conductor, 3b is center conductor, 3c is insulator, 3d is gap, 4 is ground conductor, 4a is outer conductor connection, 4b is upper ground conductor, 4c is lower ground conductor, 4d is ground Via conductors 5 are electronic components, and 7 is a lid.

  First, the circuit board of the present invention will be described in detail below.

  The circuit board of the present invention has a base 1 made of a dielectric. The circuit board of the present invention includes a cylindrical outer conductor 3a, a central conductor 3b installed on the central axis of the outer conductor 3a, and a coaxial connector 3 including an insulator 3c interposed therebetween. The base body 1 is formed with a central conductor connecting portion 2b on the upper main surface and an outer peripheral conductor connecting portion 4a formed so as to surround the central conductor connecting portion 2b in a planar shape, and the base body is formed on the inner layer or the lower main surface. A line conductor 2 is formed in parallel with the upper main surface or the lower main surface of 1, and the center conductor connecting portion 2 b and the line conductor 2 are electrically connected via a line via conductor 2 a provided therein. Yes. One end surface of the central conductor 3b of the coaxial connector 3 is electrically and mechanically joined to the central conductor connection portion 2b, and one end surface of the outer peripheral conductor 3a of the coaxial connector 3 is connected to the outer peripheral conductor connection portion 4a of the base body 1. Are electrically and mechanically joined.

  1-4, the coaxial connector 3 which consists of the cylindrical outer periphery conductor 3a, the center conductor 3b installed in the center axis | shaft, and the insulator 3c interposed between them is used. By using the coaxial connector 3, a high-frequency signal transmitted through the central conductor 3b can be transmitted in a coaxial line mode, and the impedance value of the high-frequency signal can be easily set to a desired value, for example, the same as the coaxial cable connected to the coaxial connector. it can.

The substrate 1 is formed of a dielectric made of ceramics such as alumina (Al ₂ O ₃ ) ceramics and aluminum nitride (AlN) ceramics, resin, and glass.

  Such a base | substrate 1 is produced as follows. For example, a metal paste obtained by adding and mixing a suitable organic binder, plasticizer, solvent, etc. to a high melting point metal powder such as W or Mo to a ceramic green sheet is printed by a thick film forming technique such as screen printing. Then, a metallized layer which becomes the line conductor 2, the line via conductor 2a, the center conductor connecting portion 2b, the tip end portion 2c, the outer peripheral conductor connecting portion 4a, the upper ground conductor 4b, the lower ground conductor 4c and the ground via conductor 4d is predetermined. Form into a pattern.

  Thereafter, a plurality of ceramic green sheets are laminated and fired at a temperature of about 1600 ° C. in a reducing atmosphere.

  In the coaxial connector 3, the electrical signals transmitted through the center conductor 3 b and the outer conductor 3 a are insulated from each other, and it is necessary to maintain insulation even in the base 1. Accordingly, the line conductor 2 connected to the center conductor connection portion 2b is routed as a line via conductor 2a below the center conductor connection portion 2b of the base body 1, and the outer conductor connection portion 4a and the upper ground conductor 4b formed on the surface of the base body 1. Insulate with.

  Note that after the base body 1 is fired, the line conductor 2, the central conductor connecting portion 2b, the tip end portion 2c, the outer peripheral conductor connecting portion 4a, the upper ground conductor 4b, the lower ground conductor 4c, and the like exposed on the surface of the base body 1 are exposed on the exposed surface. It is preferable to deposit a plated metal layer made of (Ni) or gold (Au) to a thickness of about 1 to 20 μm.

Further, the line conductor 2, the central conductor connecting portion 2b, the tip end portion 2c, the outer peripheral conductor connecting portion 4a, the upper ground conductor 4b, the lower ground conductor 4c and the like exposed on the surface are formed by a thin film forming method instead of being formed by a metallized layer. In this case, the line conductor 2, the central conductor connecting portion 2b, the tip end portion 2c, the outer peripheral conductor connecting portion 4a, the upper ground conductor 4b, the lower ground conductor 4c, etc. are tantalum nitride (Ta ₂ N), nichrome ( (Ni—Cr alloy), titanium (Ti), palladium (Pd), platinum (Pt), etc., and formed after firing the ceramic green sheet.

  In this case as well, it is preferable to deposit a plated metal layer made of Ni or Au to a thickness of about 1 to 20 μm on the exposed surface.

  As a result, it is possible to effectively prevent oxidative corrosion of the exposed line conductor 2, the central conductor connecting portion 2b, the tip end portion 2c, the outer peripheral conductor connecting portion 4a, the upper ground conductor 4b, the lower ground conductor 4c, and the like. The center conductor connection portion 2b and the outer conductor connection portion 4a have good wettability of the conductive adhesive 8 such as brazing material and solder, and the center conductor 3b and the outer conductor 3a are brazed or soldered to form a base. 1 can be firmly joined to a predetermined position. In addition, the connectivity between the tip 2c of the line conductor 2 and the electrical connection means 6 using a bonding wire or the like can be improved.

  The coaxial connector 3 electrically connects the electronic component 5 placed on the base 1 to an external coaxial cable, and is a cylinder made of a metal such as iron (Fe) -nickel (Ni) -cobalt (Co) alloy. Similarly, a central conductor 3b made of a metal such as an Fe—Ni—Co alloy is fixed to a central axis of the outer peripheral conductor 3a via an insulator 3c made of an insulator such as glass. Further, at the connection end with the substrate 1 (lower side surface in FIGS. 1 to 4), the end surfaces of the center conductor 3 b and the outer peripheral conductor 3 a are processed so as to be positioned on a surface that can contact the upper main surface of the substrate 1. ing.

  The central conductor 3b and the outer peripheral conductor 3a of the coaxial connector 3 are connected to the central conductor via a conductive adhesive 8 such as gold (Au) -tin (Sn) brazing or gold (Au) -germanium (Ge) brazing. By joining to the part 2b and the outer periphery conductor connection part 4a, it can join sufficiently firmly. In the case of joining with such a brazing material or solder, a preform of brazing material or solder is placed on each of the center conductor connecting portion 2b and the outer conductor connecting portion 4a of the base 1, and the center conductor 3b is placed on the preform. The outer peripheral conductor 3a is installed. Next, the brazing material or solder preform is melted by placing the coaxial connector 3 on the base body 1 via a preform in a high temperature furnace or the like and heating it to a predetermined temperature. Thereafter, the brazing material or solder is solidified by cooling, so that the center conductor 3b and the outer conductor 3a of the coaxial connector 3 are electrically and mechanically connected to the center conductor connecting portion 2b and the outer conductor connecting portion 4a of the base 1, respectively. Is done. A coaxial cable is connected to the side of the coaxial connector 3 that is not joined to the base 1, whereby a coaxial line mode high-frequency signal can be input / output between the base 1 and the outside.

  With this configuration, one end surface of the center conductor 3b is joined to the planar center conductor connecting portion 2b provided on the upper main surface of the base 1, and one end surface of the outer peripheral conductor 3a is provided on the upper main surface of the base 1. The planar outer peripheral conductor connecting portion 4a is joined. Since the center conductor 3b and the outer conductor 3a are in contact with and joined to the upper main surface of the base 1, the center conductor 3b and the outer conductor 3a can be joined to the upper main surface of the base 1 with their axial positions aligned. . Further, since the thickness of the line via conductor can be freely selected according to the thickness of the center conductor 3b, it is easy to match the impedance value at the junction to a constant value. In addition, since the connector side for transmitting in the coaxial line mode and the central conductor connecting portion 2b and the outer conductor connecting portion 4a connected thereto are in the coaxial line mode, transmission loss such as reflection loss occurs at the junction. Can be suppressed.

  Preferably, the end face of the coaxial connector 3 on the side to be joined to the base body 1 is preferably processed to be flat by polishing. By this processing, the contact between the central conductor connecting portion 2b and the outer peripheral conductor connecting portion 4a formed in a planar shape on the upper main surface of the base 1 can be improved, and the electrical connection can be made more stable.

  Also preferably, as shown in FIG. 2, the center conductor connecting portion 2b is made slightly larger than one end face of the center conductor 3b. That is, the size of the central conductor connecting portion 2b in plan view is set larger than the size of the one end surface of the central conductor 3b in plan view. The central conductor connecting portion 2b and one end surface of the central conductor 3b are preferably joined electrically and mechanically via the conductive adhesive 8.

  With this configuration, it is possible to form a meniscus of the conductive adhesive 8 that spreads from one end surface of the center conductor 3b toward the center conductor connection portion 2b, and to firmly connect the one end surface of the center conductor 3b and the center conductor connection portion 2b. Can be joined.

  More preferably, the size of the outer peripheral conductor connecting portion 4a in plan view should be larger than the size of the one end face of the outer peripheral conductor 3a in plan view. That is, it is preferable to make the width orthogonal to the circumferential direction of the outer conductor connection portion 4a thicker than the width orthogonal to the circumferential direction of the outer conductor 3a. The outer conductor connecting portion 4a and one end surface of the outer conductor 3a are electrically and mechanically joined via the conductive adhesive 8 in the same manner as the center conductor connecting portion 2b and one end surface of the center conductor 3b. It is good.

  Preferably, a gap 3d is provided between the upper main surface of the base 1 and the lower surface of the insulator 3c of the coaxial connector 3 as shown in FIG.

  With this configuration, an area where air having a low dielectric constant exists is provided between the center conductor 3b and the outer conductor 3a in the gap portion 3d, and the capacitance component generated between the center conductor 3b and the outer conductor 3a is reduced. Get smaller. Therefore, the impedance value of the electric signal transmitted through the center conductor 3b is higher than that of the portion where the insulator 3 exists. On the other hand, the center conductor connection portion 2b is larger than a plan view of one end surface of the center conductor 3b, and a capacitance component generated between the electrical signal transmitted through the center conductor connection portion 2b and the outer conductor connection portion 4a is large. The impedance value of the electric signal transmitted through the center conductor connecting portion 2b is smaller than the portion where the insulator 3 exists.

  Therefore, the electrical signal transmitted continuously through the center conductor 3b and the center conductor connection portion 2b is transmitted continuously through the portion having a high impedance value and the portion having a low impedance value. As a result, the high impedance value and the low impedance value are canceled out, and the impedance value is matched with the predetermined value, so that the electrical signal is smoothly transmitted. That is, it is possible to effectively suppress the occurrence of transmission loss such as reflection loss at the junction between the center conductor 3b and the center conductor connection portion 2b.

  The height of the gap 3d may be about 0.1 mm, and the length of the portion where the impedance value transmitted through the center conductor 3b by the gap 3d is high and the length of the portion where the impedance value is low. The electric signal can be transmitted efficiently.

  With this configuration, the conductive adhesive 8 can be scooped up on the surface of the central conductor 3b exposed by the gap 3d. By rolling up the conductive adhesive 8, a better meniscus of the conductive adhesive 8 can be formed between the central conductor 3b and the central conductor connecting portion 2b, and the central conductor 3b and the central conductor connecting portion can be formed. 2b can be firmly joined. In this case, the height dimension of the gap 3d may be adjusted.

  Preferably, as shown in FIG. 3, a support portion 10 for supporting the outer periphery of the outer peripheral conductor 3 a of the coaxial connector 3 is provided on the upper main surface of the base 1. The support portion 10 is formed of an insulator having a hole that is slightly larger than the diameter of the outer conductor 3. The coaxial connector 3 is incorporated into the base 1 by being inserted so that the outer peripheral conductor 3a of the coaxial connector 3 is in contact with the inner peripheral surface of the hole of the support portion 10 as a guide. As a result, the workability of assembling the coaxial connector 3 can be improved, one end surface of the center conductor 3b is set at a predetermined position of the center conductor connection portion 2b, and one end surface of the outer conductor 3a is connected to the outer conductor connection portion 4a. It can be electrically and mechanically joined to predetermined positions, respectively, and the impedance value of the electric signal can be easily matched to the predetermined value. As a result, the circuit board can be efficiently manufactured, and the electric signal transmitted through the center conductor 3a can be transmitted more efficiently.

  The outer surface of the outer peripheral conductor 3a and the inner peripheral surface of the hole of the support portion 10 do not necessarily have to be joined, but may be joined with an adhesive or the like as necessary.

  The planar view shape of the support portion 10 may be a circular shape similar to the outer peripheral conductor 3a of the coaxial connector 3 as shown in FIG. 3B, or the coaxial connector 3 as shown in FIG. It may be a polygonal shape such as a quadrangle in which the outer peripheral surface of the outer peripheral conductor 3a is inscribed.

  The support portion 10 may be made of a dielectric material such as ceramics, resin, or glass, or may be made of a conductive material such as metal. When it is made of a dielectric, it is preferably made of the same material as that of the substrate 1. For example, when the substrate 1 is made of ceramics and is formed by a ceramic green sheet lamination method, a ceramic green sheet serving as the support portion 10 may be laminated on the upper main surface of the substrate 1 in the ceramic green sheet lamination step. 10 can be provided in the same process as the manufacturing process of the substrate 1, and the support portion 10 can be provided with high work efficiency.

  Preferably, as shown in FIGS. 1 and 2, an upper ground conductor 4b having the same potential as that of the outer conductor connecting portion 4a is formed on the upper main surface of the base body 1 outside the outer conductor connecting portion 4a. Good. That is, the upper ground conductor 4b and the outer conductor connection portion 4a are integrally provided, and the periphery of the hole provided in the upper ground conductor 4b is used as the outer conductor connection portion 4a.

  For example, when the upper ground conductor 4b is formed by a ceramic green sheet lamination method, an appropriate organic binder, plasticizer, solvent, etc. are added to and mixed with a refractory metal powder such as W or Mo as described above. The metal paste is formed by printing on the upper main surface of the substrate 1 by a thick film forming technique such as screen printing and baking.

  Preferably, as shown in FIG. 2, a lower ground conductor 4c is formed on the lower main surface of the base 1, and the upper ground conductor 4b and the lower ground conductor 4c are connected via a ground via conductor 4d. Keep it.

  With this configuration, the ground potential of the ground conductor can be made the same at each of the upper main surface, the inner main surface, and the lower main surface of the base body 1, and the impedance value of the electric signal to be transmitted can be easily matched. it can.

  As shown in FIG. 2B, a plurality of ground via conductors 4d are preferably provided on the circumference of an equal distance centered on the line via conductor 2a in plan view. With this configuration, the electrical signal transmitted through the line via conductor 2a is grounded by the plurality of ground via conductors 4d provided on the circumference of the equidistant centered on the line via conductor 2a, and the line via conductor 2a. Can be transmitted in a transmission mode close to a coaxial line. As a result, between the coaxial connector 3 and the base body 1, the electric signal can be set to substantially the same transmission mode (coaxial line mode), and the connection becomes easy.

  Preferably, the substrate 1 is made of ceramics, and the coaxial connector 3 is brazed or soldered.

With this configuration, the base 1 is made of a heat-resistant material, and the coaxial connector 3 is joined to the base 1 by a heat-resistant material, so that the circuit board can withstand use in a high-temperature atmosphere. be able to. For example, by using Au—Sn brazing, Au—Ge brazing or the like as a brazing material or solder, it can be used in a high temperature atmosphere up to about 300 ° C., and Al ₂ O ₃ ceramics is used for the substrate 1. Thereby, it can be set as the circuit board with the intensity | strength of the base | substrate 1 being high.

In the circuit board of the present invention, preferably, as shown in FIG. 4, a concave portion 1 a for accommodating the electronic component 5 is formed on the upper main surface of the base 1. For example, as shown in FIG. 4, the recess 1 a is formed by providing a side wall 1 c so as to surround the mounting portion 1 b of the electronic component 5 on the base 1. The side wall portion 1c is made of a dielectric such as ceramics such as Al ₂ O ₃ ceramics and AlN ceramics, resin, and glass, and may be formed integrally with the bottom plate 1d on which the mounting portion 1b is formed. Alternatively, the side wall portion 1c may be made of a metal such as Fe-Ni-Co alloy, copper (Cu), copper (Cu) -chromium (Cr), and in this case, as shown in FIG. The portion 1c is joined to the bottom plate portion 1d made of a dielectric by a method such as brazing or soldering so as to surround the mounting portion 1b. The side wall portion 1c made of metal is manufactured in a predetermined shape by subjecting the ingot to a conventionally known metal processing method such as rolling or punching. Moreover, you may form the baseplate part 1d and the side wall part 1c by integral molding with resin.

  When a large amount of heat is generated from the electronic component 5, the bottom plate portion 1d is preferably formed from AlN ceramics having high thermal conductivity. With this configuration, heat generated from the electronic component 5 can be efficiently dissipated to the outside.

  Alternatively, only the mounting portion 1b of the bottom plate portion 1d may be formed of metal, and in this case as well, heat generated from the electronic component 5 can be efficiently dissipated to the outside. The metal that forms such a mounting portion 1b is made of a material having excellent heat dissipation such as Cu, Cu-W, Cu-Mo, Cu-Cr, and the like, in a through hole provided in an insulator such as ceramics. Joined to fit.

  Further, when the side wall 1c is made of metal, as shown in FIG. 4A, the line conductor 2 is not electrically connected to the side wall 1c at the portion where the side wall 1c is joined. Is placed inside the substrate 1. Although not shown, the side wall portion 1c is preferably electrically connected to the upper ground conductor 4b, and the side wall portion 1c can function as a case ground, thereby strengthening the ground potential of the upper ground conductor 4b. Can do.

  Further, since the lower ground conductor 4c is connected to the upper ground conductor 4b via the ground via conductor 4d, it is electrically connected to the metal side wall 1c to form a case ground, and the upper ground conductor 4b The potential is the same as that of the lower ground conductor 4c, and a very stable ground potential can be obtained. The case ground is a ground potential serving as a reference of the circuit board. By maintaining the ground potential of the upper ground conductor 4b, the lower ground conductor 4c, and the metal side wall 1c at the same potential, the value of the ground potential is set. Can be stable. As a result, a stable high frequency signal can flow through the line conductor 2.

  Moreover, when the side wall part 1c consists of metal, the lid body 7 can be joined to the upper surface of the side wall part 1c using welding methods, such as a seam welding method, and the effect that the lid body 7 can be easily joined airtightly. There is.

As a form for joining the lid 7 by using a welding method such as a seam welding method, the lower side (bottom plate 1d side) of the side wall portion 1c is a ceramic or resin such as Al ₂ O ₃ ceramics or AlN ceramics. , Formed of a glass dielectric, and the upper side of the side wall 1c joined to the lid 7 may be formed of metal. Also with this configuration, the lid body 7 can be joined to the upper surface of the side wall portion 1c by using a welding method such as a seam welding method, so that the lid body 7 can be easily joined in an airtight manner.

  In addition, since the tip end 2c of the line conductor 2 is provided inside the recess 1a, the electronic component 5 accommodated inside the recess 1a is connected to the line conductor 2 and is electrically connected to the outside of the recess 1a. Signals can be input and output satisfactorily.

  Preferably, the surface to which the coaxial connector 3 is joined is provided above the mounting portion 1b of the electronic component 5 as shown in FIG.

  With this configuration, the line via conductor 2a is provided downward from the central conductor connecting portion 2b to which the central conductor 3b of the coaxial connector 3 is joined to the same surface as the mounting portion 1b, and then the line conductor 2 is mounted on the mounting portion of the electronic component 5 By providing up to about 1b, the coaxial connector 3 and the electronic component 5 can be connected. As a result, compared to the case where the coaxial connector 3 and the electronic component 5 shown in FIG. 4A are provided on the same surface, the line via conductor 2a is reduced from two to one, and the wiring of the line conductor 2 is simplified. In addition, the number of bent portions can be reduced, and transmission loss such as reflection loss can be suppressed from occurring in the electric signal transmitted through the line conductor 2.

  Next, the electronic device of the present invention will be described in detail below.

  In the electronic device of the present invention, an electronic component 5 such as a semiconductor laser (LD), a photodiode (PD), a transistor, an IC, an LSI, or the like, or a passive component such as a semiconductor element or a capacitor is mounted on the inside of the recess 1a. The electronic component 5 is stored. For example, the recess 1a is formed in a region surrounded by the frame-shaped side wall 1c and the bottom plate 1d, and the electronic component 5 is mounted on the mounting portion 1b on the bottom plate 1a serving as the bottom surface of the recess 1a.

  The electrode of the electronic component 5 is electrically connected to the tip end portion 2c of the line conductor 2 via an electrical connection means 6 such as a bonding wire.

  That is, one end of the line conductor 2 is electrically connected to the central conductor 3 b of the coaxial connector 3 and the other end is electrically connected to the electronic component 5.

  Here, it is preferable that the same-surface ground conductors are provided at equal intervals on both sides of the same surface of the end portion 2c of the line conductor 2, and this configuration allows the end portion 2c to be a coplanar transmission line. This makes it easier to handle higher frequency signals. When the electrode of the electronic component 5 is electrically connected to the end of the line conductor 2 opposite to the side to which the center conductor 3b is connected, the other end of the upper ground conductor 4b provided on both sides of the line conductor 2 is connected to the electron. By electrically connecting to the grounding electrode of the component 5, the transmission mode of the connection portion of the line conductor 2 with the electronic component 5 is made the same as the coplanar transmission line mode often used for the electrode portion of the electronic component 5. It is possible to easily match the transmission mode of the high-frequency signal transmitted through the line conductor 2 with the transmission mode of the electrode portion of the electronic component 5. High-frequency signals can be transmitted efficiently.

  The lid 7 is made of a metal such as an Fe—Ni—Co alloy, ceramics, glass, resin, or the like. The cross-sectional shape of the lid body 7 is a flat plate shape shown in FIGS. 4A and 4B or an inverted concave shape (cap shape).

  The electronic component 5 is placed and fixed on the mounting portion 1b in the recess 1a of the circuit board of the present invention, and the electrode is electrically connected to the tip end portion 2c of the line conductor 2 through the electrical connection means 6 such as a bonding wire. Thereafter, the lid 7 is attached to the upper surface of the side wall portion 2c by a soldering method, a brazing method, a seam weld method, or the like, thereby obtaining an electronic device as a product. With this configuration, the electronic component 5 can be hermetically accommodated in the recess 1a, and the electronic component 5 can be stably operated.

  In such an electronic device, by connecting a coaxial cable connected to an external electric circuit to the coaxial connector 3, the electronic component 5 housed therein is electrically connected to the external electric circuit.

  With the above configuration, an electric signal using the circuit board of the present invention can be efficiently transmitted, and an electronic device having excellent operability can be obtained.

  Note that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention. For example, the cross-sectional shape of the side wall 1c may be a step shape. Moreover, the planar view shape of the recessed part 1a may be a rectangle, or a circle. Alternatively, instead of providing the grounding via conductor 4d, a side conductor may be provided on a side surface parallel to the direction in which the line via conductor 2a of the base 1 is extended. Also with this configuration, the upper ground conductor 4b and the lower ground conductor 4c can be electrically connected.

(A) is sectional drawing which shows an example of embodiment about the circuit board of this invention, (b) is sectional drawing which shows the other example of embodiment about the circuit board of this invention, (c) is FIG. And FIG. 1B is a plan view showing an upper main surface of the base body of the circuit board of FIG. (A) is sectional drawing which shows the other example of embodiment about the circuit board of this invention, (b) is a top view which shows the upper side main surface of a base | substrate about the circuit board of Fig.2 (a). (A) is sectional drawing which shows the other example of embodiment about the circuit board of this invention, (b), (c) is a top view which shows the upper main surface of a base | substrate about the circuit board of Fig.3 (a) It is. (A) is sectional drawing which shows an example of embodiment about the circuit board and electronic device of this invention, (b) is sectional drawing which shows the other example of embodiment about the circuit board and electronic device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Substrate 1a: Concave part 1b: Placement part 1c: Side wall part 2: Line conductor 2a: Line via conductor 2b: Center conductor connection part 2c: Tip part 3: Coaxial connector 3a: Outer conductor 3b: Center conductor 3c: Insulation Body 3d: Gap 4a: Peripheral conductor connection 4b: Upper ground conductor 4c: Lower ground conductor 4d: Ground via conductor 5: Electronic component 6: Electrical connection means 7: Lid 8: Conductive adhesive
10: Support section

Claims (9)

A line conductor formed on an inner layer or a lower main surface, a central conductor connecting portion formed on an upper main surface, and an outer peripheral conductor connecting portion formed around the central conductor connecting portion; A base body having a via conductor for a line provided in a body and electrically connected to the line conductor and the central conductor connection;
A cylindrical outer conductor, a central conductor installed on the central axis of the outer conductor, and a coaxial connector made of an insulator interposed therebetween,
One end surface of the central conductor of the coaxial connector is electrically and mechanically joined to the central conductor connecting portion, and one end surface of the outer peripheral conductor of the coaxial connector is electrically and mechanically joined to the outer peripheral conductor connecting portion. A circuit board characterized by being bonded. The circuit board according to claim 1, wherein the central conductor connecting portion is larger than a cross section of the central conductor. The circuit board according to claim 2, wherein a gap is provided between the base and the insulator of the coaxial connector. The circuit board according to any one of claims 1 to 3, wherein a support portion for supporting an outer periphery of the outer peripheral conductor of the coaxial connector is provided on an upper main surface of the base body. 5. The circuit according to claim 1, wherein an upper ground conductor is formed on an upper main surface of the base body, and the outer peripheral conductor connection portion is connected to the upper ground conductor. substrate. 6. The circuit according to claim 5, wherein a lower ground conductor is formed on a lower main surface of the base body, and the upper ground conductor and the lower ground conductor are connected via a ground via conductor. substrate. The circuit board according to claim 1, wherein the substrate is made of ceramics. A concave portion for accommodating an electronic component is formed on the upper main surface of the base body, the central conductor connecting portion and the outer peripheral conductor connecting portion are provided outside the concave portion, and the coaxial connector is joined to the inner side of the concave portion. The circuit board according to claim 1, wherein the line conductor is led out to the circuit board. 9. A circuit board according to claim 8, an electronic component housed in the recess and electrically connected to the line conductor, and a lid joined to the upper surface of the recess so as to close the recess. An electronic device characterized by that.

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