JP2002076722A - Wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the transmission loss of a signal between a signal transmission line formed on the surface of a wiring board and a waveguide, and to improve reliability. SOLUTION: A wiring board is equipped with a ceramic dielectric board 1, a signal transmission line 5 that is applied and formed on one surface of the dielectric board 1 and has an open end 5a, a metal cover 2 mounted on one of the dielectric board 1, a waveguide bonding member 17 that an opening part 18 is formed at a corresponding position through the open end 5a of the signal transmission line 5 and the dielectric board 1. Connecting and fixing an open end of the waveguide B to the opening part 18 of the waveguide connection member 17 enables the signal transmission between the signal transmission line 5 and the waveguide B. In the wiring board, a difference in thermal expansion of the ceramic dielectric board 1 and the waveguide bonding member 17 in the temperature range from the normal temperature to 400 deg.C is 5×10-6/ deg.C or less. The ratio of a volume of the cover to a volume of the bonding member in the metal cover 2 and the waveguide connection member 17 is 0.5 to 2. Then curvature of a bonding face of the waveguide connection member 17 and the waveguide B is controlled to be 50 μm/cm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency package for accommodating a high-frequency element such as a high-frequency semiconductor element or a high-frequency passive element, a circuit board on which a package containing such elements is mounted, or various elements. The present invention relates to a wiring board that can be connected to a waveguide, and is used for a circuit board or the like in which is directly mounted on a surface, and a wiring board that can efficiently transmit a signal between a signal transmission line and a waveguide.

[0002]

2. Description of the Related Art In recent years, society has become more computerized, and information has been transmitted wirelessly and personalized as represented by mobile phones. Under these circumstances, in order to enable even higher-speed and large-capacity information transmission, millimeter-wave (30 to 300 GHz)
The development of a semiconductor device operating in the z) region is in progress. Recently, with the progress of such high-frequency semiconductor device technology,
Various application systems using millimeter wave radio waves such as inter-vehicle radar and wireless LAN have been proposed as applications. For example, an inter-vehicle radar using millimeter waves (see IEICE Electronics Society Conference 1995, SC-7-6), a cordless camera system (see IEICE Electronics Society Conference 1995, C-137), high-speed wireless communication LA
N (see IEICE Electronics Society Conference, 1995, C-139).

As the applications of millimeter waves have progressed, the development of elemental technologies for enabling these applications has been progressing at the same time. In particular, various electronic components have required transmission characteristics. However, how to reduce the size and cost is a major issue.

Among such element technologies, how to connect a circuit board or a package containing a high-frequency element to an external circuit board with a simple and small structure is regarded as an important element. In particular, how to connect an external circuit board on which a waveguide with the smallest transmission loss is formed to a circuit board or a package on which a high-frequency element is mounted has been a major problem.

Conventional methods for connecting a circuit board or a package to a waveguide formed on an external circuit board include a method of converting a high-frequency package into a coaxial line once using a connector and connecting to a waveguide. In the external circuit board, a method is used in which the waveguide is once connected to a microstrip line or the like, and then the microstrip line is connected to a high-frequency package.

Recently, a simple structure in which a waveguide is directly coupled to an opening provided in a package to couple the waveguide with a microstrip line in the package is disclosed in Japanese Patent Laid-Open No. 6-283914. It has been proposed in Kaihei 11-243307 and the like.

Further, the present applicant has disclosed Japanese Patent Application Laid-Open No. 11-11 / 1999.
No. 2209 proposes a structure in which a microstrip line and a waveguide in a cavity are electromagnetically coupled by a slot formed in a ground layer, so that a hermetic sealing of a semiconductor element can be easily performed.

[0008]

However, as described above, in the method of once connecting a waveguide to a package via another transmission line form such as a connector or a microstrip line, the connection structure itself is complicated. Along with
Since it is necessary to secure areas for forming connectors and other transmission lines, there is a problem that the connection structure itself becomes large. In addition, there is a possibility that transmission loss may increase due to other line forms or connectors.

[0009] On the other hand, a method of direct introduction from the waveguide to the inside of the cavity of the package in the form of an electromagnetic wave is effective in that the connection structure can be reduced in size, but passes through a cavity forming member such as a lid. In order to reduce the loss of electromagnetic waves, it is necessary to use a material having a small dielectric constant and a small dielectric loss tangent for the passing part, and therefore, a process of embedding a low dielectric constant and low loss material such as quartz is required Becomes Such an embedding process not only impairs the reliability of hermetic sealing, but is completely unsuitable for mass production.

It is also conceivable that all the cavity forming members are made of a material having a low dielectric constant and a low loss.
Various materials such as mechanical strength, hermetic sealing properties, and metallization properties are required in addition to the electrical properties as materials constituting the package. Suitable materials that satisfy all of these properties and can be manufactured at low cost Is not found.

Further, in Japanese Patent Application Laid-Open No. 11-112209, it is necessary to directly screw the waveguide to the package in order to attach the waveguide to the package. This causes a defect. Therefore, it has been proposed that a connecting member is brazed to the package side and a waveguide is screwed to the connecting member.

In this case, the brazing temperature of the connecting member is 70.
Since the temperature is extremely high at 0 ° C. or higher, when the dielectric substrate of the package is made of low-temperature fired ceramics, re-firing is performed in the brazing process, and the electrical characteristics (dielectric constant, dielectric loss ) May change. As a result, the original transmission characteristics may be impaired.

Further, there is a problem that the package does not warp due to a difference in thermal characteristics between the connection member and the dielectric material. As a result, a gap is generated at the junction between the waveguide and the connection member or between the connection member and the package, which causes a problem that transmission characteristics between the waveguide and the microstrip line are deteriorated.

Further, if the screws are further tightened in order to reduce the gap between the two, cracks and breakage may occur at locations where the stress of the dielectric substrate of the package is concentrated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a small signal transmission loss between a signal transmission line formed on the surface of a wiring board and a waveguide, and has excellent reliability. It is an object of the present invention to provide a printed circuit board.

[0016]

According to the present invention, there is provided a ceramic dielectric substrate, a signal transmission line formed on one surface of the dielectric substrate and having an open end, and one of the dielectric substrates. A metal lid attached to the surface of the substrate, and an opening formed at a position opposed to the open end of the signal transmission line via the dielectric substrate and attached to the other surface of the dielectric substrate. A signal transmission line and the waveguide can be transmitted by connecting and fixing an open end of the waveguide to an opening of the waveguide connection member. In a simple wiring board, by suppressing the amount of warpage of the connection surface of the waveguide connecting member with the waveguide to 50 μm / cm or less, the signal transmission line formed on the surface of the wiring board and the waveguide Low signal loss during connection and low reflection connection That.

In order to suppress the warpage of the connecting surface of the waveguide connecting member to the waveguide to 50 μm / cm or less, the difference in thermal expansion coefficient between the waveguide connecting member and the dielectric substrate is set to 400 from normal temperature.
It is desirable that the temperature be 5 × 10 ⁻⁶ / ° C. or less in the range of ° C. Further, the (U) -shaped metal lid attached to one surface side of the wiring board and the waveguide connection member attached to the rear surface side are: (volume of connection member) / (cover) The ratio of (body volume) is preferably 0.5 to 2.

A ground layer having a slot hole is formed inside or on the back of the ceramic dielectric substrate at a position facing the open end of the signal transmission line, and the signal transmission line is formed through the slot hole. By electromagnetically coupling the waveguide and the waveguide, and particularly forming a dielectric portion on the surface of the ground layer on which the slot hole is formed, a connection with a small loss and a good sealing property can be achieved.

In the electromagnetic coupling structure, it is more preferable that a conductor layer is further formed inside the dielectric portion or on the surface on the connection side with the waveguide, at a position facing the slot hole. By forming a dielectric layer on the back surface of the substrate and surrounding the dielectric portion with a plurality of vertical conductors formed on the dielectric layer, the dielectric portion is formed by simultaneous firing with the dielectric substrate or the like. can do.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of a high-frequency package as a typical application example of the structure of a wiring board according to the present invention will be described with reference to the drawings.

FIG. 1 shows a high-frequency package which is an example of the present invention, wherein (a) is a schematic sectional view,
(B) is a plan view showing a pattern on one surface of the dielectric substrate, (c) is a plan view showing a pattern on the bottom surface of the first dielectric layer of the package, and (d) connects a waveguide to the package. It is a schematic sectional view at the time of doing.

First, according to the high-frequency package A1 shown in FIG. 1, the high-frequency element 4 is mounted on the surface of the dielectric substrate 1 in the cavity 3 formed by the dielectric substrate 1 and the metal lid 2. Have been. A signal transmission line 5 having one end connected to the high-frequency element 4 and having an open end 5 a is formed on the surface of the dielectric substrate 1 on the cavity 3 side, and is connected to the high-frequency element 4.

The metal lid 2 has a U-shaped cross section and is brazed to the surface of the dielectric substrate. The cavity 3 is hermetically sealed by the metal lid 2. Have been.

On the other hand, on the surface of the dielectric substrate 1 opposite to the surface on which the signal transmission line 5 and the high-frequency element 4 are mounted, a ground layer 7 is formed on one surface, and the signal transmission of the ground layer 7 is performed. An iris (hereinafter, referred to as a slot hole) 6 in which a conductor is not formed is formed in a portion facing the open end 5a of the line 5.

In this package, the signal transmission line 5 forms a central conductor and forms a microstrip line with the ground layer 7. The signal transmission line is not limited to the above-mentioned microstrip line, and another ground layer may be formed on both sides of the signal transmission line (center conductor), and a line having a grounded coplanar structure may be formed together with the ground layer 7. Also, the signal transmission line 5 of the dielectric substrate 1
Is formed with a conductor layer 8 for brazing the lid 2.

In the high-frequency package A1 shown in FIG. 1, a first dielectric layer 10 is formed on the surface of the ground layer 7 where the slot hole 6 is formed. A plurality of vertical conductors 14 are arranged in the first dielectric layer 10 so as to surround the slot holes 6 of the ground layer 7 in a plan view at intervals less than a quarter of the signal wavelength. ing. In a region surrounded by the vertical conductor 14, a dielectric portion 9 is formed in order to match the characteristic impedances of the microstrip line and the waveguide and to achieve wideband transmission conversion. A conductor layer 11 is formed on the surface of the first dielectric layer 10, and the conductor layer 11 and the ground layer 7 are connected by the vertical conductor 14. Although the vertical conductor 14 has a columnar shape here, there is no particular problem if the vertical conductor 14 has a prismatic shape or an elliptical shape.

In the above line configuration, the signal transmission line 5 of the microstrip line is electromagnetically coupled to the slot hole 6, in other words, the slot hole 6 is electromagnetically coupled.
Power. This electromagnetic coupling structure is specifically described in JP-A-3-129903. As shown in the plan view of the dielectric substrate 1 in FIG. By forming the open end 5a so as to protrude from the center of the slot hole 6 by a length L of a quarter wavelength of the signal frequency, electromagnetic coupling can be achieved. However, electromagnetic coupling is not limited to the combination of dimensions described above, and good coupling is possible with other combinations.

In the package A1 shown in FIG.
A waveguide connecting member 17 made of copper-tungsten, copper, Kovar, or the like is attached to the conductor layer 11 with a brazing agent or the like. The connection member 17 has an opening 1 at a position facing the open end 5 a of the signal transmission line 5 via the dielectric substrate 1.
8 are formed. The opening 18 has substantially the same shape as the inner diameter of the waveguide 17 to be connected.

Then, a flange B ′ provided at the open end of the waveguide B is brazed to the connection member 17, or the flange B ′ is screwed to the connection member 17 to connect the waveguide B. Secure to the connection member.

By electrically connecting the conductor wall 16 of the waveguide B to the ground layer 7 via the conductor layer 11 and the vertical conductor 14 in this manner, the ground layer 7 and the conductor wall 16 of the waveguide B are electrically connected. Can be made common.

In such a connection structure with the waveguide B,
High-frequency package A1 to which waveguide connecting member 17 is joined
The flange B 'at the open end of the waveguide B needs to be closely joined to obtain good transmission characteristics. for that reason,
It is important that the amount of warpage of the connection surface of the waveguide connecting member 17 connected to the flange B ′ at the open end of the waveguide B is 50 μm / cm or less, and particularly 40 μm / cm or less. desirable. This is because when the warpage of the connection surface of the waveguide connecting member 17 connected to the flange B ′ at the open end of the waveguide B exceeds 50 μm / cm, the high-frequency package A1
As a result, a large gap is generated between the waveguide B and the flange B ′ of the waveguide B, and the gap partially changes the current flow path between the waveguide connecting member 17 and the flange B ′, resulting in transmission. This is because the characteristics are degraded. In addition, when the gap becomes large, in a high frequency region of a millimeter wave or more, an electromagnetic field leaks from the gap and causes deterioration of characteristics.

As described above, in order to reduce the warpage of the connection surface of the waveguide connecting member 17 connected to the flange B 'at the open end of the waveguide B to the above range, the high-frequency package A1 is used.
It is desirable that the difference in thermal expansion coefficient between the dielectric substrate 1 and the connecting member 17 be 5 × 10 ⁻⁶ / ° C. or less, particularly 3 × 10 ⁻⁶ / ° C. or less in the range from room temperature to 400 ° C. Furthermore, the difference in thermal expansion coefficient between the dielectric substrate 1 and the metal lid 2 of the high-frequency package A1 in the range from room temperature to 400 ° C. is 5 × 10 ⁻⁶ / ° C. or less, particularly 3 × 10 ⁻⁶ / ° C. It is desirable that the temperature is not more than ° C.

Further, the metal cover 2 provided on the front and back of the high-frequency package A1 and the connection member 17 are formed of the same material, and the connection member 17, the dielectric substrate 1 and the metal cover 2 are connected to each other. The combination can reduce the occurrence of residual stress and suppress the occurrence of warpage.

In this case, it is desirable that the ratio of (volume of connection member) / (volume of lid) be 0.5 to 2, particularly 0.7 to 1.3. That is, if the volume ratio deviates from the above range, the high-frequency package A1, the metal lid 2
And the balance due to the residual stress generated between the connecting members 17 is lost, and the stress is concentrated on one surface side of the package A1 and becomes unbalanced, so that the package A1 itself is warped and connected to the package A1. Metal cover 2 and connection member 17
The warp itself occurs, and the warp amount becomes larger than 50 μm / cm.

Further, according to this structure, the waveguide B can be firmly joined to the high-frequency package A1 to which the connecting member 17 is joined, and the package A1 and the waveguide B
Connection reliability can be improved.

Although the connecting member 17 is integrally formed on the bottom surface of the dielectric substrate 1 in FIG.
7 may be provided separately from the input conversion unit and the output conversion unit of the package A1.

Further, in this structure, the size of the dielectric portion 9 surrounded by the vertical conductor 14 provided in the first dielectric layer 10 is reduced by the size of the opening 18 formed in the connection member 17.
By making the connection member 17 smaller than the above, it is possible to suppress a variation in characteristics due to a deviation at the time of connection between the connection member 17 and the dielectric portion 9, and to use a brazing material at a step portion of a connection end face between the conductor layer 11 and the connection member 17. It is possible to form a meniscus,
Stress concentration at the connection end face can be avoided, and the generation of stress due to a temperature change occurring during brazing can be suppressed, and the yield can be improved.

The package A1 having the structure shown in FIG. 1 includes a ceramic insulating material for the dielectric substrate 1 and the dielectric layer 10, a high-frequency transmission line 5, a ground layer 7, a conductor layer 11, and a vertical conductor 1.
This is advantageous in that a conductive material such as No. 4 can be manufactured by printing and applying a conductive paste to a ceramic material before firing using a well-known ceramic laminating technique, and firing the batch.

FIG. 2 shows a modification of the high-frequency package A1 shown in FIG.
FIG. 3 is a schematic cross-sectional view when connecting the. According to the high-frequency package A2, the conductor layer 19 can be provided at a position facing the slot hole 6 inside the dielectric portion 9. The conductor layer 19 has a function of dividing an electromagnetic field generated in the dielectric portion into two. The conductor layer 19 may be formed on the surface of the dielectric portion 9 on the connection side with the waveguide B.

In the package A1 shown in FIG.
The high-frequency element 4 has a structure mounted on the surface of the dielectric substrate 1. As a modified example, as shown in a package A2 in FIG. 2, a cavity 2 is formed by the dielectric substrate 1 and the dielectric layer 10. Thus, it is also possible to form the ground layer 7 on the surface of the dielectric layer 10 and further mount the high-frequency element 4 on the surface of the ground layer 7.

Further, in the package A1 shown in FIG. 1, a first dielectric layer 10 is formed on the surface of a ground layer 7 formed on the back surface of the dielectric substrate 1, and the first dielectric layer 1
0, a vertical conductor 14 is provided, and the dielectric portion 9 is made internal.
As shown in the package A3 in FIG. 3, the first dielectric layer 1
Without forming 0, the dielectric portion 9 may be directly bonded to the surface of the slot hole 6 in the ground layer 10, and in that case, the connecting member 17 may be directly bonded to the ground layer 7. In such a case, the package A2 in FIG.
Similarly to the conductor layer 19, the conductor layer 19 can be formed inside the dielectric portion 9 or on the surface on the connection side with the waveguide B.

In the high-frequency packages A1, A2, and A3 of the present invention shown in FIGS.
The dielectric portion 9 and the dielectric layer 10 can be made of ceramics, organic resin, or a composite thereof. For example, as ceramics, Al ₂ O ₃ , A
ceramic materials such as 1N and Si ₃ N ₄ , glass materials,
Alternatively, it can be formed by a glass ceramic material composed of a composite of glass and an inorganic filler such as Al ₂ O ₃ , SiO ₂ , MgO, etc., formed by using these raw material powders into a predetermined substrate shape, and then firing. Is done. The organic resin can be formed on a printed circuit board or a Teflon substrate made of an organic material.

Each transmission line and ground layer for transmitting signals can be made of a high melting point metal such as tungsten or molybdenum, or a low resistance metal such as gold, silver or copper. It can be appropriately selected according to the substrate material, and can be integrally formed by a conventional lamination technique.

For example, when the substrate is made of Al ₂ O ₃ , AlN, Si ₃
When it is formed of a ceramic material such as N _4, it is preferable to print and apply it to a green body using a high melting point metal such as tungsten or molybdenum, and fire it at a temperature of 1500 to 1900 ° C. When the substrate is formed of a glass material or a glass ceramic material, it can be manufactured by similarly baking at a temperature of 800 to 1100 ° C. using copper, gold, silver, or the like. When the substrate is formed of an insulating material containing an organic resin, a line or a ground layer can be formed by applying a paste using copper, gold, silver, or the like, or by bonding a metal foil. In the case where the substrate is formed of a glass material, a glass ceramic material, or an insulating material including an organic resin, in the case of joining with a connection member,
It is necessary to select brazing material, conductive adhesive, An-
It is desirable to use Sn, An-Si, or the like. In addition, the metal lid 2 attached to the dielectric substrate 1 and the connecting member 17
Are Fe-Co-Ni alloy, Ni-Cr-Fe alloy, C
It is preferably formed of at least one metal material selected from the group consisting of u-W and Cu. Alternatively, the lid 2 may be made of the above-described insulating material for forming the dielectric substrate 1 and a conductive material applied to the inner surface of the lid.
Also, the connection member 17 may be made of the insulating material and formed by applying a conductive material to the inner wall of the opening 18.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The package A1 shown in FIG.
An evaluation package A4 shown in FIG. 4 having no high-frequency element mounting portion was manufactured, and connection characteristics between the waveguide B and the signal transmission line 5 were evaluated. The evaluation package has a target frequency of 77
GHz. A vector network analyzer was used for the measurement. The measurement form is as follows.

As shown in FIG. 4, the waveguide B from the network analyzer is connected to the connection member 1 of the evaluation package A4.
7 and connected by screwing (not shown), the signal in the waveguide B is converted by the input converter x1, passes through the microstrip line 5, is converted again by the output converter x2, and is B was adopted. S21 was evaluated for the produced package.

The dielectric substrate and the dielectric layer 10 in the package A4 have a dielectric constant of 9.0, and a
Alumina ceramics having a coefficient of thermal expansion of 7 × 10 ⁻⁶ / ° C. at 00 ° C. is used, and tungsten is used as a conductor material on the surface and inside of the line 5, the ground layer 7, the vertical conductor 14, and the conductor layers 8 and 11. Body substrate 1 and dielectric layer 1
0 and formed simultaneously.

The exposed surfaces of the lines 5 and the conductor layers 8 and 11 were plated with Au having a thickness of 3 μm. The waveguide connecting member 17 and the lid 2 were joined to the conductor layers 8 and 11 with an Ag solder using an Fe—Co—Ni alloy.

In the package, a connecting member,
Various materials shown in Table 1 were used for the lid. Table 1 shows the thermal expansion difference (α difference) between each material and the dielectric substrate. The volume ratio between the connection member X and the lid Y was determined by changing the thickness of the connection member and the lid, and the results are shown in Table 1.

Further, by using a surface roughness meter, the stylus is moved by 1 cm in one direction with respect to the connection surface other than the opening of the waveguide connection member 17 connected to the waveguide B. The maximum warpage (μm) / measured length (cm) was measured from the chart obtained. This measurement was performed five times in each of the long side direction and the short side direction of the package, and the average thereof was obtained, and this was defined as the amount of warpage of the connection surface.

After the evaluation of the transmission characteristics of the package, a thermal shock test was performed to evaluate the reliability. This evaluation was based on a liquid tank, and was held in water at 0 ° C. and 100 ° C. for 5 minutes each. In the table, 〇 indicates that no abnormality was observed even after 1000 cycles, and X indicates that failure occurred after less than 1000 cycles. In addition, the thing which generation | occurrence | production of a crack etc. was already recognized at the stage before the test was shown as initial fracture.

[0052]

[Table 1]

As is clear from Table 1, the sample No. In Nos. 4 to 11, the warpage amount was 50 μm /
cm or less, the transmission characteristic (S21) was 4.5 dB or less, and no occurrence of cracks or the like was recognized even after 1000 cycles in reliability evaluation.

On the other hand, the sample N without the lid was used.
o. 1-3, the thermal expansion difference between the connecting member and the dielectric substrate is 5 ×
Sample No. larger than 10 ⁻⁶ / ° C. Sample Nos. 14 and 15 having a ratio of (volume of connection member) / (volume of lid) smaller than 0.5. 12. Sample N with ratio greater than 2
o. In No. 13, the warpage amount was larger than 50 μm / cm, and as a result, the transmission characteristics deteriorated. In the reliability tests, the initial fracture or thermal shock test was 1
Destruction was observed at 00 cycles, indicating low reliability.

[0055]

As described above in detail, according to the present invention, when a signal is transmitted between the signal transmission line formed on the surface of the wiring board and the waveguide, the connection between the waveguide and the waveguide at the waveguide connecting member is performed. By limiting the amount of warpage of the surface to 50 μm / cm or less, the connection with the waveguide can be performed stably, thereby reducing the signal transmission loss between the signal transmission line and the waveguide and improving the reliability. be able to.

[Brief description of the drawings]

FIG. 1 shows a high-frequency package A1 which is an example of a wiring board according to the present invention, wherein FIG.
(B) is a plan view showing a pattern on one surface of the dielectric substrate, (c) is a plan view showing a pattern on the bottom surface of the first dielectric layer of the package A1, and (d) is a waveguide in the package A1. FIG. 3 is a schematic cross-sectional view when connecting the.

FIG. 2 is a schematic sectional view when a waveguide B is connected to a high frequency package A2 according to another embodiment of the present invention.

FIG. 3 is a schematic sectional view when a waveguide B is connected to a high-frequency package A3 according to still another embodiment of the present invention.

FIG. 4 is a schematic sectional view when a waveguide B is connected to an evaluation package A4 in the embodiment.

[Explanation of symbols]

 A1, A2, A3 High frequency package B Waveguide B 'Flange 1 Dielectric substrate 2 Metal lid 3 Cavity 4 High frequency element 5 Signal transmission line 5a Open end 6 Slot hole 7 Ground layer 8, 11, 19 Conductive layer 9 Dielectric part 10 Dielectric layer 14 Vertical conductor 16 Waveguide wall 17 Waveguide connection member

Claims (7)

[Claims] 1. A ceramic dielectric substrate, a signal transmission line attached to one surface of the dielectric substrate and having an open end, and a metal lid attached to one surface of the dielectric substrate And a waveguide connecting member attached to the other surface of the dielectric substrate and having an opening formed at a position facing the open end of the signal transmission line via the dielectric substrate. A wiring board capable of transmitting a signal between the signal transmission line and the waveguide by connecting and fixing an open end of the waveguide to an opening of the waveguide connection member; The warpage of the connecting surface of the member with the waveguide is 50 μm.
m / cm or less. 2. The thermal expansion difference between the ceramic dielectric substrate and the waveguide connecting member in the range from room temperature to 400.degree.
A wiring board having a temperature of ^10-6 / C or less. 3. The ratio of (volume of connection member) / (volume of lid) between the metal lid and the waveguide connecting member is 0.5 to 2. The wiring board according to claim 1 or 2. 4. A ground layer having a slot hole at a position facing an open end of the signal transmission line inside or at the back of the ceramic dielectric substrate, and the signal transmission line is formed through the slot hole. 4. The apparatus according to claim 1, wherein said waveguide and said waveguide are electromagnetically coupled.
The wiring board as described. 5. The wiring board according to claim 4, wherein a dielectric portion is formed on the surface of the ground layer on which the slot holes are formed. 6. The wiring board according to claim 5, wherein a conductor layer is formed inside the dielectric portion or on a surface on the connection side with the waveguide, facing the slot hole. 7. A dielectric layer is formed on a back surface of said ceramic dielectric substrate, and said dielectric portion is formed by being surrounded by a plurality of vertical conductors formed on said dielectric layer. The wiring board according to claim 5 or 6, wherein