JP2001015878A - High frequency wiring board and method of manufacturing the same - Google Patents

Abstract

(57) Abstract: Provided is a high-frequency wiring board capable of making fine wiring and lowering the resistance of a conductor and transmitting a reduced transmission loss of a high-frequency signal. In a high-frequency wiring board having a high-frequency wiring layer formed on a surface and / or inside of a dielectric substrate made of glass ceramic, at least a part of the high-frequency wiring layer has a metal content. It is made of a high-purity metal conductor of 99% by weight or more, and has a surface roughness (Ra) at the interface with the dielectric substrate 2 of 0.3 μm 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 wiring board for transmitting a high-frequency signal in a microwave band to a millimeter-wave band, and more particularly to a high-frequency wiring board capable of reducing transmission loss of a high-frequency signal and a method of manufacturing the same. It is.

[0002]

2. Description of the Related Art Conventionally, a multilayer ceramic wiring board capable of relatively high-density wiring has been widely used as a wiring board, for example, a multilayer wiring board used for a package for housing a semiconductor element. This multilayer ceramic wiring board
It is composed of a dielectric substrate such as alumina or glass ceramic, and a wiring conductor made of metal such as W, Mo, Cu, or Ag formed on the surface thereof, and a cavity is formed in a part of the dielectric substrate. The semiconductor element is accommodated in the cavity, and the cavity is hermetically sealed by the lid.

[0003] In recent years, with the era of advanced information, the frequency band used has been increasingly shifting to a higher frequency band. In a wiring board on which such a high-frequency circuit element for transmitting a high-frequency signal is mounted, it is important to transmit the high-frequency signal without loss, and the conductor forming the high-frequency wiring layer has a small resistance and a high dielectric constant. It is required that the dielectric loss of the body substrate in a high frequency region be small.

The above-described high-frequency wiring layer is formed by a conductor layer of a center conductor such as a microstrip line and a ground layer. A high-frequency signal is generated by a magnetic field generated between the center conductor and the ground layer. The transmission characteristics of the high-frequency signal greatly depend on the state of the interface between the dielectric substrate sandwiched between the center conductor and the ground layer and the conductor layer of the center conductor and the ground layer.

Conventionally, a high-frequency wiring board of this type has a dielectric layer made of, for example, glass ceramics on the surface thereof.
A method is known in which a high-frequency wiring pattern is formed by a screen printing method or the like using a metallized paste containing a low-resistance metal such as Cu or Ag as a main component, and is fired simultaneously with a dielectric layer.

[0006]

However, in such a method of printing and firing a conductive paste, the high-frequency wiring layer is formed by sintering a metal powder, and thus has many voids. In order to match the heat shrinkage behavior of the dielectric layer and the high-frequency wiring layer, the resistance cannot be reduced because a filler component such as ceramics or glass is added to the conductor paste. Also, with this method, it is difficult to reduce the wiring width of the high-frequency wiring layer to 80 μm or less, and there is a limit to miniaturization.

Further, according to this method, the surface roughness (R) of the interface with the dielectric layer is caused by agglomeration of the metal powder in the conductor paste.
a) increases, and the reactivity at the interface between the dielectric layer and the high-frequency wiring layer during firing is high, and the resistance at the interface of the high-frequency wiring layer increases, so that the transmission loss of the high-frequency signal increases. There was a problem of doing.

Therefore, the present invention enables fine wiring and low resistance in a glass-ceramic wiring board, and has a small transmission loss in a high-frequency band even when a high-frequency element such as an MIC or MMIC is mounted, and is efficient. An object of the present invention is to provide a high-frequency wiring board to be operated.

[0009]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have transferred a wiring circuit pattern made of metal foil to the surface of a ceramic green sheet and simultaneously fired the same on a glass ceramic wiring board. hand,
By reducing the surface roughness of the interface between the high-frequency wiring layer and the dielectric substrate and reducing the reactivity at the interface, fine wiring and low resistance are possible, and transmission loss of high-frequency signals is reduced. The inventors have found out that they can do so and have reached the present invention.

That is, the high-frequency wiring board of the present invention comprises:
A high-frequency wiring board comprising a high-frequency wiring layer formed on the surface and / or inside of a dielectric substrate made of glass ceramic, wherein at least a part of the high-frequency wiring layer has a metal content of 99% by weight. In addition to the high-purity metal conductor described above, the surface roughness (Ra) at the interface with the dielectric substrate is 0.3 μm or less.

The reaction phase at the interface between the dielectric substrate and the high-frequency wiring layer is 10 μm or less, and the high-frequency wiring layer is formed of a strip line, a microstrip line, a coplanar line, a grounded coplanar line, Having one kind selected from a triplate line,
It is preferable that the high-frequency wiring layer is at least one selected from Cu, Ag, Au, Pt, and Pd, and the high-frequency wiring layer is made of a metal foil.

The method of manufacturing a high-frequency wiring board according to the present invention is also characterized in that: (a) the surface of the transfer film is made of a high-purity metal conductor having a metal content of 99% by weight or more and has a surface roughness (Ra) of 0.3 μm; A step of preparing the following high-frequency wiring pattern; (b) a step of forming a green sheet with the glass ceramic composition; and (c) obtaining a surface of the green sheet obtained by the step (b) by the step (a). A step of transferring the high-frequency wiring pattern to a predetermined position on the surface of the green sheet by laminating and pressing the high-frequency wiring layer forming surface of the obtained transfer film, and a step of (d) and (c). Baking at a temperature lower than the melting point of the high-frequency wiring layer.

Here, in the step (d), the dielectric substrate is densified to a relative density of 95% or more, and the shrinkage in the X-Y direction by firing in the step (d) is 10% or less. Preferably, the wiring circuit pattern is made of a metal foil.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing an example of a high-frequency wiring board according to the present invention.

According to the high-frequency wiring board 1 shown in FIG. 1, the dielectric substrate 2 includes a plurality of glass ceramic dielectric layers 2a to 2a.
d, and the dielectric layer 2
a to 2d and the surface of the dielectric substrate 2 have a thickness of 3 to 2
A high-frequency wiring layer 3 made of a high-purity metal foil having a metal component content of about 0 μm and a content of 99% or more is formed by deposition.
Further, via-hole conductors 4 having a diameter of 80 to 200 μm are formed in the dielectric layers 2 a to 2 d of the dielectric substrate so as to penetrate the thickness direction, and a predetermined circuit is formed by the high-frequency wiring layer 3 and the via-hole conductor 4. ing.

The dielectric substrate 2 is made of zinc borosilicate glass,
It is a so-called glass ceramic containing a glass component such as borosilicate glass or lithium silicate glass such as lead borosilicate glass or aluminoborosilicate glass, and an inorganic filler.

The glass component of the glass ceramic is a glass frit containing a plurality of metal oxides. , At least one crystal of petalite, slausonite, diopside or a substituted derivative thereof is desirably deposited. To reduce the dielectric loss of the dielectric substrate 2, quartz, cordierite, mullite, spinel, garnite It is desirable that a low-loss crystal phase is precipitated in a high-frequency region such as willemite, slausonite, and diopside, and that it does not contain lead that increases dielectric loss.

Further, the coefficient of thermal expansion of the dielectric substrate 2 is increased,
To reduce the difference in thermal expansion coefficient from the high-frequency wiring layer,
It is desirable that a crystal phase having a large coefficient of thermal expansion, such as quartz, cristobalite, tridymite, and garnet, be precipitated.

The inorganic filler component includes quartz, cristobalite, tridymite, amorphous SiO 2
₂ , alumina, mullite, cordierite, forsterite, ZnO, TiO _{2 and the} like can be used, but in order to reduce the dielectric loss of the dielectric substrate 2, quartz, amorphous SiO ₂ , alumina, mullite, cordierite, etc. It is desirable that a low-loss crystal phase is precipitated in a high-frequency region such as light and forsterite. Further, in order to increase the coefficient of thermal expansion of the dielectric substrate 2, it is desirable that quartz, cristobalite, and tridymite, which are SiO ₂ crystal phases, are precipitated, especially a quartz crystal phase (coefficient of thermal expansion: 17.5 ppm / ° C.).

Further, according to the present invention, by reducing the surface roughness of the interface between the dielectric substrate 2 and the high-frequency wiring layer 3, the transmission characteristics of high-frequency signals can be improved. That is, the high-frequency signal is transmitted to the dielectric substrate 2 and the high-frequency wiring layer 3.
This is because an electric field and a magnetic field are most concentrated on the interface with the interface, and if the surface roughness of the interface increases, the signal transmission path becomes longer and the resistance increases, thereby increasing the signal transmission loss. In order to improve the transmission characteristics of high frequency signals,
The surface roughness (Ra) of the interface between the dielectric substrate 2 and the high-frequency wiring layer 3 needs to be 0.3 μm or less, particularly 0.2 μm or less. In order to keep the surface roughness (Ra) within the above range, it is desirable that the surface roughness (Rmax) be 20 μm or less, particularly 10 μm or less. Further, the surface roughness (Ra) of the interface between the dielectric substrate 2 and the conductor wiring layer 3 is set to 0.3.
In order to make the average particle size of the inorganic filler 5 μm or less, the relative density of the dielectric substrate 2 is 95% or less in order to make the surface roughness (Rmax) 20 μm or less.
More preferably, it is preferably 98% or more.

The high-frequency wiring layer 3 is made of a high-purity metal conductor having a metal content of 99% by weight or more.
It is desirable to be made of Au, Pt, Pd or a mixture thereof, and further desirably made of metal foil in terms of miniaturization of the high-frequency wiring layer 3 and low resistance. Also,
The metal foil may be grown by firing.

In the high-frequency wiring layer 3, the high-frequency transmission line is selected from a strip line, a microstrip line, a coplanar line, a coplanar line with ground, and a triplate line in order to efficiently transmit a high-frequency signal. Desirably one is present.

In the high-frequency wiring layer 3, a low-frequency signal transmission line, a power supply line, a capacitor, a resistor, an inductor and the like may be formed, and the metal content is lower than 99%. A circuit layer made of a conductor may be formed.

Further, the dielectric substrate 2 and the high-frequency wiring layer 3
By controlling the thickness of the reaction layer at the interface with the conductor wiring layer to 10 μm or less, good transmission of high-frequency signals becomes possible without increasing the resistance value at the interface with the conductor wiring layer 3.

That is, the dielectric substrate 2 contains components having low reactivity with the high-frequency wiring layer 3, for example, Si, Mg and the like, and does not contain Pb, Ti, Li, Na, K and the like having high reactivity. It is desirable.

Here, the thickness of the interface reaction layer in the present invention is the thickness of the region where the components of the dielectric substrate and the components of the conductor wiring layer are measured by electron beam probe microanalysis (EPMA) analysis in the cross section of the wiring substrate. Refers to the thickness.

The high-frequency wiring layer 3 having the above structure has an interface conductivity of 0.3 × 10 ⁸ Ω ^{−1 at} the interface with the dielectric substrate 2.
M ^-1 or more, especially 0.35 × 10 ⁸ Ω ^-1 · m ^-1 or more, so that transmission loss of high frequency signals can be reduced.

The high-frequency wiring board of the present invention has
It is particularly effective when transmitting a high frequency signal of not less than 50 GHz, particularly not less than 50 GHz, and the transmission characteristic (S ₂₁ ) at 50 to 110 GHz is not more than 1.5 dB / cm, particularly 1.0 dB.
/ Cm or less.

The via-hole conductor 4 desirably has a component similar to that of the high-frequency wiring layer 3 described above, and is formed by sintering a metal powder.

On the surface of the wiring board 2, wiring for connection to an electronic component 6, such as an IC chip, pads for mounting the electronic component 6, and a conductive film for shielding are provided. On the back surface, terminals for connection to an external circuit are provided. Electrodes are formed, and the electronic component 6 is joined to the high-frequency wiring layer 5 via solder, a conductive adhesive, or the like.
Although not shown, a thick-film resistor film such as tantalum silicide or molybdenum silicide or a wiring protection film such as epoxy resin may be further formed on the surface of the wiring board 2 as necessary. .

The multilayer wiring board according to the present invention has a surface obtained by adding a filler component such as glass to a thermosetting resin such as an epoxy resin, a phenol resin, an aramid resin, a polyimide resin, a polyolefin resin, or the like. A
It can be mounted via a solder ball or the like on a conductor layer of an external circuit board on which a conductor layer containing a metal such as l, Ni, Pb-Sn or the like is attached.

Next, a method for manufacturing the wiring board of the present invention will be described. First, after mixing the above-mentioned crystallized glass and an inorganic filler having an average particle diameter of 3 μm or less and adding an organic binder, the mixture is formed into a sheet by a known forming method such as a doctor blade method, a rolling method, and a pressing method. To produce a green sheet.

Next, a diameter of 80 to 20 is applied to the green sheet by laser, micro drill, punching or the like.
A via hole of 0 μm is formed, and the inside thereof is filled with a conductive paste. The conductive paste is a metal powder similar to the high-frequency wiring layer, an organic binder such as an acrylic resin,
An organic solvent such as toluene, isopropyl alcohol, and acetone is added and mixed to adjust the viscosity. It is preferable that the organic binder is mixed in a ratio of 0.5 to 5.0 parts by weight based on 100 parts by weight of the metal component, and the organic solvent is mixed in a ratio of 5 to 100 parts by weight based on 100 parts by weight of the solid component and the organic binder. Note that a slight glass component or the like may be added to the conductor paste.

On the other hand, a method for forming a high-frequency wiring pattern is to bond a high-purity metal foil of the above-mentioned metal component having a thickness of 3 to 20 μm on a polymer film, and apply a resist on the surface of the metal layer in a circuit pattern. After coating, a method of forming a high-frequency wiring layer by performing an etching treatment and a resist removal is preferably used. According to this method,
Since fine processing is possible without cutting or sagging of wiring, fine wiring having a wiring width of 50 μm or less and a distance between wirings of 50 μm or less can be formed.

In order to reduce the surface roughness (Ra) of the interface between the dielectric substrate and the high-frequency wiring layer to 0.3 μm or less, the surface roughness (Ra) of the metal foil formed on the film is required.
Is important to be 0.3 μm or less.

Then, a high-purity metal foil is transferred onto the surface of the green sheet. As a method of transfer, the high-frequency wiring pattern formation surface of the transfer film on which the high-frequency wiring pattern is formed is aligned with the surface of the dielectric sheet on which the via-hole conductor is formed and laminated and pressed.
By peeling off the transfer sheet, it is possible to form one unit of a wiring sheet having a high-frequency wiring layer to which via-hole conductors are connected. Thereafter, the obtained one unit of wiring layer is laminated and pressed to form a laminate.

Next, this laminate is subjected to a heat treatment at 400 to 750 ° C. in an oxidizing or weakly oxidizing atmosphere to decompose and remove the organic components in the green sheet and the via-hole conductor paste. By co-firing in a non-oxidizing atmosphere at a temperature lower than the melting point of the high-purity metal conductor, preferably at 800 to 1000 ° C, particularly 900 to 1000 ° C, the relative density of the dielectric substrate becomes 95% or more, especially 98%. %, And the thickness of the reaction layer at the interface between the dielectric substrate and the high-frequency wiring layer is 1%.
A multilayer wiring board having a high-frequency wiring layer of 0 μm or less and a via-hole conductor can be manufactured.

In order to improve the adhesion of the high-frequency wiring layer to the insulating substrate while suppressing deformation and cracking of the dielectric substrate and the high-frequency wiring layer during firing or cooling after firing, Stacking and firing a green sheet having a firing start temperature higher than that of the above-described green sheet and not sintering even at a firing temperature of 1000 ° C. or less, and a non-shrinking sintered body, By baking while applying pressure, the shrinkage in the X-Y direction of the dielectric substrate can be reduced to 10% or less, and according to this method, the dimensional accuracy of the high-frequency wiring layer can be improved.

In order to mount the obtained multilayer wiring board on an external circuit board, solder or the like is applied to connection pads formed on the back surface of the multilayer wiring board and solder balls are attached thereto.
This is placed on the conductor layer on the surface of the external circuit board, heated, and the solder ball is heated and melted, so that the conductor layer and the solder ball are fixed and electrically connected.

[0040]

EXAMPLES (Examples) First, a binder was added to a composition composed of glass and a filler having the composition shown in Table 1 to form a predetermined shape, and fired in nitrogen or oxygen at a temperature shown in Table 1. Thus, a pellet having a diameter of 20 mm × 10 mm was prepared. The bulk density of the obtained porcelain was measured by the Archimedes method, and the relative density, which is a ratio to the theoretical density, was calculated. Further, the precipitated crystal phase in the porcelain was identified by powder X-ray diffraction. Further, the dielectric constant and dielectric loss of the porcelain were measured at 60 GHz by a dielectric resonator method using a network analyzer and a synthesized sweeper. The results are shown in Table 1.

[0041]

[Table 1]

On the other hand, a slurry was prepared by adding an acrylic resin as a binder, DBP (dibutyl phthalate) as a plasticizer, and toluene and isopropyl alcohol as a solvent to the same composition as in Table 1 to prepare a slurry having a thickness of 200 to 250 μm by a doctor blade method. A green sheet was produced.

On the other hand, the same powder as the components forming the high-frequency wiring layer shown in Table 2 having an average particle diameter of 2 to 5 μm, an acrylic resin, and 0.5% by weight of alumina as a filler with respect to the powder, DBP and acetone were added and kneaded with a three-roll mill to prepare a via-hole conductor paste.

Then, a via hole having a diameter of 100 μm was formed at a predetermined portion of the green sheet by laser or punching, and the via hole conductor paste was filled in the via hole by screen printing.

Next, the purity of 99.8 was formed on the surface of the PET film.
% Metal foil composed of the components shown in Table 2 with high purity,
By forming a photosensitive resist, exposing, developing, etching, and removing the resist, a plurality of high-frequency wiring layers having a wiring width and a wiring distance shown in Table 2 were formed. Then, the transfer sheet is laminated on the green sheet on which the via hole is formed while aligning the via hole with the green sheet.
Thermocompression bonding was performed at kgf / cm ² . Thereafter, by peeling only the transfer film, a unit wiring sheet having a high-frequency wiring layer to which via-hole conductors were connected was formed.
Furthermore, six sheets of this arbitrary one unit wiring sheet are laminated,
A laminate was formed.

Next, for the unfired laminate,
In order to decompose and remove organic components such as an organic binder, a heat treatment is performed at 750 ° C. for 1 hour in nitrogen or air, and then at 900 ° C. and 200 kgf in air or nitrogen atmosphere.
/ Cm ² uniaxial pressure firing from the laminating direction for 1 hour,
A wiring board was manufactured.

The resulting width 0.2 mm, the wiring board comprising a high-frequency wiring layer consisting of the microstrip line length 30 mm, the S ₂₁ is a transmission loss as an evaluation of transmission characteristics in 50~110GHz with a network analyzer It was measured. An EPMA (Electron Beam Probe Microanalyzer) analysis is performed on the interface between the dielectric substrate and the conductor wiring layer in the cross section of the wiring substrate, and the components constituting the dielectric substrate and the components constituting the high-frequency wiring layer are mixed. The thickness of the region to be treated was measured and is shown in Table 2 as the thickness of the reaction layer. In addition, the surface roughness (Ra) and the surface roughness (Rmax) of the interface of the high-frequency wiring layer with the dielectric substrate were measured from SEM and BEM photographs of the cross section, and are shown in Table 2.

A high-frequency wiring layer was formed on the entire surface of each of the above-mentioned various dielectric substrates in the same manner as described above, and the interface conductivity between the high-frequency wiring layer and the dielectric substrate was measured. The evaluation board had a high-frequency wiring layer thickness of 0.01 mm, and the upper and lower dielectric substrates had a thickness of 0.2 mm. The interface conductivity was measured by the dielectric cylinder resonator method described below.

The method of measuring the interface conductivity using the dielectric cylinder resonator method is as follows. A dielectric cylinder made of a dielectric material having a known relative dielectric constant and dielectric loss tangent is provided on both end faces or one end face of the dielectric cylinder.
By forming a dielectric resonator by attaching a dielectric substrate having the above-mentioned conductor layer formed therein in a predetermined relationship, the conductivity at the interface between the metal layer and the dielectric substrate, that is, at the metal layer interface, Is a method of measuring

The principle of this measuring method is that a conductive plate (usually a dielectric material) which is large enough to neglect the edge effect is provided on both end surfaces of a dielectric cylinder having a predetermined dimensional ratio (height t / diameter d). If a conductor plate having a diameter D of about three times the diameter d of the cylinder is provided in parallel and sandwiched to form an electromagnetic field resonator, T
This is because the high-frequency current flowing through the conductor plate in the E _omn resonance mode is distributed only on the short-circuit surface, that is, only at the interface between the dielectric and the conductor.

More specifically, as shown in FIG. 2, sapphire having an end surface perpendicular to the C axis (diameter d = 10000)
mm, height t = 5.004 mm) on both end surfaces of the dielectric cylinder 20, the inside of the conductor layer 21 formed as described above.
Is formed, and a dielectric resonator 23 is formed by sandwiching a dielectric column from both ends. In the dielectric resonator 23, the TE _omn mode (m = 1, 2, 2)
.., N = 1, 2, 3,...)
1. The high-frequency current flowing in the
Using the distribution only at the interface of the dielectric substrate 22 in contact with the substrate, the measured TE _omn mode (m = 1, 2, 3 _,.
· ·, N = 1, 2, 3, the resonance frequency f ₀ and the unloaded Q of ...), it is possible to calculate the interfacial conductivity sigma _int from Q _u by the following equation (1) the number 1.

[0052]

(Equation 1)

However, A, B ₁ and B ₂ represent the following equation (2)
(3) Calculated by equation (4).

[0054]

(Equation 2)

Here, tan δ ₁ and tan δ in the equation (1)
₂ is the dielectric loss tangent between the dielectric cylinder 20 and the dielectric substrate 22, μ is the magnetic permeability of the conductor layer 21, ω is 2πf ₀ , ∬ | H |
² dS magnetic field of the integration of the upper and lower metal layer interface, W ^e is the resonator of the field energy, W _d1 ^e and W _d2 ^e is the dielectric cylinder 20
And the electric field energy on the side of the dielectric substrate 22 that is in contact with the dielectric cylinder 20. Note that W ^e , W _d1 ^e , W
ε ₁ and tan δ ₁ of the dielectric cylinder 20 necessary for calculating _d2 ^e
Is based on the dielectric constant ε ′ ₂ and ta of the dielectric substrate 22 by the dielectric cylinder resonator method disclosed in JIS-R-1627 “Test method for dielectric properties of fine ceramics for microwave”.
nδ ₂ is described in “Science Technique MW87-7”, “Microwave Complex Permittivity Measurement of Dielectric Plate Material” by Kobayashi and Sato et al. (1987)
) Can be measured by a well-known method such as the cavity resonator method disclosed in U.S. Pat. The interface conductivity measured in this way is shown in Table 1 as the interface conductivity of the center conductor.
In addition, it was confirmed that the interface conductivity of both interfaces of the conductor layer in the evaluation substrate was substantially the same.

For comparison, the conductor formation method was replaced with the transfer of metal foil, and 0.5 wt% of alumina and 2 wt% of acrylic resin were used as fillers in Cu powder having an average particle size of 5 μm.
And DBP and acetone were added, and a wiring board was prepared in exactly the same manner as in the example except that the paste was kneaded with three rolls and printed on the wiring pattern by screen printing.
It was evaluated similarly. The results are shown in Table 2.

[0057]

[Table 2]

From Table 2, it can be seen that Sample No. 3 in which the glass content of the dielectric substrate is low was obtained. Sample Nos. 1 and 11 using alkali glass and lead borosilicate glass. In Nos. 15 and 16, the surface roughness (Ra) of the interface between the dielectric substrate and the high-frequency wiring layer was larger than 0.3 μm, and the transmission loss of the high-frequency signal became large.

Further, the metal foil for forming the high-frequency wiring layer had a large surface roughness (Ra). In No. 20, the surface roughness (Ra) of the interface between the dielectric substrate and the high-frequency wiring layer was larger than 0.3 μm, and the transmission loss of the high-frequency signal was large.

Further, the sample No. in which a high-frequency wiring layer was formed using a Cu paste was used. In 22, the line width is 0.05mm
Cannot be formed, and the sample No. 23
In this case, the reactivity between the dielectric substrate and the high-frequency wiring layer was high, the surface roughness (Ra) exceeded 0.3 μm, and the transmission loss was large.

On the other hand, in the sample according to the present invention,
In each case, the surface roughness (Ra) of the interface between the dielectric substrate and the high-frequency wiring layer was 0.3 μm or less, and the transmission loss was small.

[0062]

As described in detail above, according to the present invention,
Since the wiring board has a dielectric substrate made of glass ceramic and a high-frequency wiring layer made of a high-purity metal conductor having a metal content of 99% by weight or more, fine wiring and low resistance of the conductor are possible. Becomes In addition, the present invention provides a high-frequency wiring board with reduced transmission loss of high-frequency signals because the surface roughness of the interface between the dielectric substrate and the high-frequency wiring layer can be reduced, and the reactivity at the interface can be reduced. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a high-frequency wiring board according to the present invention.

FIG. 2 is a diagram for explaining a method for evaluating interface conductivity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High frequency wiring board 2 Dielectric substrate 3 High frequency wiring layer 4 Via hole conductor 5 High frequency transmission line 6 Electronic component

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shinya Kawai 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima F-term in Kyocera Research Institute (reference) 4E351 AA07 AA13 BB01 BB31 BB49 CC12 CC17 CC19 CC20 CC31 DD04 DD05 DD06 DD20 DD31 DD41 DD47 DD54 EE09 EE13 EE24 GG01 GG07 5E346 AA13 AA15 AA24 AA43 BB02 BB03 BB04 BB06 BB11 CC18 CC31 CC32 CC38 CC39 DD12 DD31 DD33 EE24 EE27 EE29 FF18 GG02 GG03 GG09 HH02H06

Claims (9)

[Claims] 1. A high-frequency wiring board having a high-frequency wiring layer formed on a surface and / or inside of a dielectric substrate made of glass ceramic, wherein at least a part of the high-frequency wiring layer has a metal content. A high-frequency wiring board comprising a high-purity metal conductor of 99% by weight or more and having a surface roughness (Ra) of 0.3 μm or less at an interface with the dielectric substrate. 2. The high-frequency wiring board according to claim 1, wherein a reaction phase at an interface between the dielectric substrate and the high-frequency wiring layer is 10 μm or less. 3. A high-frequency wiring layer comprising: a strip line;
3. The high-frequency wiring board according to claim 1, comprising one selected from a microstrip line, a coplanar line, a grounded coplanar line, and a triplate line. 4. The high-frequency wiring layer is made of Cu, Ag, Au,
4. The high-frequency wiring board according to claim 1, wherein the wiring board is at least one selected from Pt and Pd. 5. The high-frequency wiring board according to claim 1, wherein said high-frequency wiring layer is made of a metal foil. 6. A step of producing a high-frequency wiring pattern having a surface roughness (Ra) of 0.3 μm or less made of a high-purity metal conductor having a metal component content of 99% by weight or more on the surface of the transfer film. (B) a step of forming a green sheet from the glass-ceramic composition; and (c) forming a high-frequency wiring layer of the transfer film obtained by the step (a) on the surface of the green sheet obtained by the step (b). Transferring the high-frequency wiring pattern to a predetermined position on the surface of the green sheet by laminating and pressing the surfaces, and (d).
(C) baking the green sheet obtained in the step at a temperature lower than the melting point of the high-frequency wiring layer. 7. The method for manufacturing a high-frequency wiring board according to claim 6, wherein in the step (d), the dielectric substrate is densified to a relative density of 95% or more. 8. The method of manufacturing a high-frequency wiring board according to claim 6, wherein the shrinkage in the XY directions due to the firing in the step (d) is 10% or less. 9. The method for manufacturing a high-frequency wiring board according to claim 6, wherein said wiring circuit pattern is made of a metal foil.