JP2002359472A - Optoelectronic mounting circuit board and mounting board - Google Patents

Abstract

(57) [Problem] To provide an optoelectronic mounting circuit board excellent in heat dissipation and low in loss of an input signal of an external electric signal. An insulating layer made of an alumina sintered body and a dielectric layer having a lower dielectric constant than the insulating layer are integrally laminated, and a conductor layer is formed on the surface and / or inside thereof. The formed insulating substrate, the optical waveguide 6 and the optical semiconductor element 5 mounted on one surface side of the insulating substrate, and the electronic semiconductor element 7 mounted on one or the other surface of the insulating substrate; An external connection terminal 10 provided on the dielectric layer 3 of the substrate is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical semiconductor device, an electronic semiconductor device and / or an optoelectronic semiconductor device mounted thereon.
The present invention relates to an opto-electronic mounting circuit board and a mounting board applicable to high frequency signals.

[0002]

2. Description of the Related Art With the spread of multimedia in recent years, it has become necessary to transmit and receive enormous amounts of image data, and high-frequency signal processing is indispensable for electronic equipment that requires high-speed operation. On the other hand, optical communication capable of high-speed, large-capacity transmission / reception has been attracting attention. However, since electronic semiconductor elements and multi-chip modules are complicatedly connected by optical waveguides, it is necessary to frequently cross waveguides. In order to cope with the downsizing of the device by performing the optical signal and the electric signal processing on the same mounting substrate and to cope with complicated optical interconnection, an optical semiconductor element and Optoelectronic mounting circuits on which electronic semiconductor elements and the like are mounted are used.

A ceramic wiring board provided with such an optoelectronic mounting circuit is required to have high heat dissipation with an increase in the amount of heat generated by high integration and high frequency operation, as well as to increase the operation speed. Therefore, low resistance of conductors is required, and alumina having relatively high thermal conductivity and excellent reliability is used as an insulating substrate, and a conductor layer made of a high melting point metal such as W or Mo is coated on the surface or inside thereof. A ceramic wiring board formed by deposition is often used.

However, in a conductor layer made of a high melting point metal which has been widely used, the resistance can be reduced only to about 8 mΩ / □ at most, and the signal insertion loss becomes extremely high.
There has been a problem that good high-frequency characteristics cannot be obtained. Furthermore, with the increase in the frequency of signals, wiring boards, especially,
When the dielectric constant of the insulating layer portion on which the conductor layer for the signal input terminal is applied is high, there is a problem that signal reflection is increased and characteristics are deteriorated.

Therefore, alumina is used as an insulating substrate,
Japanese Patent Application Laid-Open No. 7-15101 proposes reducing insertion loss by forming a low resistance conductor Cu or a conductor layer obtained by combining Cu and W or Mo by simultaneous firing.

Further, regarding signal transmission characteristics, Japanese Patent Laid-Open No. 3-239394 proposes a method of using a glass ceramic having a low dielectric constant for an insulating layer of a signal input portion and integrating it with tempered glass in order to suppress signal reflection. Have been.

[0007]

However, according to the method described in Japanese Patent Application Laid-Open No. Hei 7-15101, after all the conductor layers are disposed inside the insulating substrate and fired simultaneously, the insulating layer on the surface is polished or the like. To form a surface conductor layer by exposing the inner conductor layer to the surface by polishing and removing, or to form the surface conductor layer by a thick film method or a thin film method on the surface of the wiring board after firing. Since a polishing step, a thick film forming step, a thin film forming step, and the like are indispensable steps for forming the conductor layer, the number of manufacturing steps is increased, and there is a problem that the yield is reduced and the cost is increased.

In the method described in Japanese Patent Application Laid-Open No. 3-239394, since a glass ceramic or the like is used for an insulating substrate, the dielectric constant of the substrate can be set low and the resistance of the wiring metal can be reduced. Is not smoothly diffused, which causes a malfunction of the element itself.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optoelectronic mounting circuit board which is excellent in heat dissipation and has little loss of an input signal of an external electric signal.

[0010]

Means for Solving the Problems The inventors of the present invention have studied the above problems, and as a result, have found that an outer layer is formed on a dielectric layer of a laminate comprising an alumina insulating layer and a low dielectric constant dielectric layer. This is based on the finding that the provision of the connection terminal can provide a thermally conductive optoelectronic mounting circuit board having a small input loss of a high-frequency signal and excellent heat dissipation.

That is, an insulating layer made of an alumina sintered body,
A dielectric layer having a lower dielectric constant than the insulating layer is integrally laminated, and Au, Ag, and C are formed on the surface and / or inside.
an insulating substrate on which at least one conductive layer of u and Pt is formed, an optical waveguide and an optical semiconductor element mounted on one surface side of the insulating substrate, and mounted on one or the other surface of the insulating substrate And an external connection terminal provided on the dielectric layer of the insulating substrate. As a result, a low-loss optoelectronic mounting circuit board is realized at the input section of the high-frequency signal.

In particular, it is preferable that the insulating layer and / or the dielectric layer is formed of a laminate. Accordingly, even when a plurality of semiconductors are mounted, wiring can be performed inside the stacked body, and high-density mounting is facilitated.

Preferably, the electronic semiconductor element and the optical semiconductor element are mounted on opposing surfaces of the insulating substrate. Thereby, miniaturization is possible and high reliability is obtained.

Further, it is preferable that the electronic semiconductor element is accommodated in a cavity provided on the surface of the insulating substrate, and the cavity is hermetically sealed by a lid. This stabilizes the characteristics of the electronic semiconductor device,
Reliability can be improved.

Further, it is preferable that the dielectric layer of the insulating substrate is formed on a part of the surface of the insulating layer. Accordingly, it is possible to mount a component having a large calorific value such as an electronic semiconductor element on the insulating layer having a high thermal conductivity provided with the dielectric layer.

Further, it is preferable that the optical semiconductor element is provided inside the optical waveguide. This allows
The characteristics of the optical semiconductor element are stabilized, and the reliability can be improved.

Further, the dielectric layer is preferably a sintered body containing at least one of mullite, forsterite, enstatite, silica and cordierite as a main component. Thereby, it becomes easy to correspond to a higher high frequency.

Further, it is preferable that the alumina sintered body contains silica and Mn ₂ O ₃ . Thereby, low-temperature sintering becomes possible and the product yield can be increased.

It is preferable that the conductor layer contains W and / or Mo. This makes it easy to obtain an opto-electronics mounted circuit board that enables low-resistance wiring and that can handle high frequencies with small conductor loss even in the internal circuit.

Further, it is preferable that the sheet resistance of the conductor layer is 8 mΩ / □ or less in terms of the conductor thickness of 15 μm. This facilitates downsizing of components due to a reduction in the wiring width.

Further, in the mounting board of the present invention, an electronic circuit including a capacitor, a resistor and a wiring conductor is formed on the surface of the mother board, and the optoelectronic mounting circuit board according to any one of claims 1 to 10. Is mounted on the electronic circuit via an external connection terminal, and a reflection loss when a high frequency signal of 40 GHz is input to the optoelectronic mounting circuit board is −1.
It is characterized by being equal to or less than 0.0 dB, thereby realizing optical communication capable of high-speed, large-capacity transmission and reception.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION
This will be described with reference to the drawings. FIG. 1 is a schematic sectional view of an optoelectronic mounting circuit board of the present invention. That is, an insulating layer 1 composed of alumina sintered bodies 1a to 1d, which is a thin layer sintered body mainly composed of alumina, and a dielectric layer 2 having a lower dielectric constant than the alumina sintered bodies 1a to 1d are integrally formed. It is laminated.

The insulating layer 1 may be composed of one layer of the alumina sintered body. However, in consideration of high-density mounting of semiconductors, wiring and miniaturization, a plurality of alumina sintered bodies 1a to 1a are used.
Preferably, the laminate is made of 1d. Also figure
1, the insulating layer 1 has four layers of alumina sintered bodies 1a to 1a.
Although it is composed of d, the number of alumina sintered bodies is not particularly limited, and may be appropriately determined depending on the amount of wiring, the position of the semiconductor, and the like.

Alumina sintered bodies 1 a to 1 constituting insulating layer 1
A surface conductor layer 3a and an internal conductor layer 3b are formed on the surface or interface of 1d, and a ground conductor layer 3c is provided between the dielectric layer 2 and the alumina insulating layer 1. In addition, a via-hole conductor 3d penetrating one or more alumina sintered bodies is provided. Therefore, the conductor layer 3 is formed on the surface of the insulating substrate and / or
Or it is provided inside.

An optical semiconductor element 5 is provided on one surface side of the insulating substrate.
And the optical waveguide 6 is formed. The optical waveguide 6 has a structure optically connected to the optical semiconductor element 5, and has a structure in which an optical waveguide clad 6b is provided around an optical waveguide core 6a. The optical waveguide 6 exists on at least a part of one surface side of the insulating layer 1,
The optical semiconductor element 5 may be located outside the optical waveguide 6, but in order to enhance the reliability of the optical semiconductor element 5 and prevent malfunction, the optical semiconductor element 5 is particularly provided inside the optical waveguide 6. Is preferred.

Further, an electronic semiconductor element 7 is mounted on the other surface of the insulating layer 1. That is, the electronic semiconductor element 7 and the optical semiconductor element 5 are respectively mounted on opposing surfaces of the insulating substrate. With such a configuration, a large number of electronic semiconductor elements 7 and optical semiconductor elements 5 can be mounted on one insulating substrate, miniaturization of products by higher-density mounting is promoted, and reliability is improved. Can be enhanced.

Here, the dielectric layer 2 may be integrally laminated on the entire surface of the alumina sintered body 1d constituting the insulating substrate, but as shown in FIG. Is preferably formed. With this configuration, the surface of the insulating layer 1 is also exposed on the surface of the insulating substrate on the side of the dielectric layer 2, so that the electronic semiconductor element 7 can be mounted thereon, and the mounting density can be increased.

The electronic semiconductor element 7 can be provided on one surface of the insulating layer 1 on which the optical semiconductor element 5 and the optical waveguide 6 are provided. That is, the optical waveguide 6 may be formed on a part of the surface, and the electronic semiconductor element 7 may be mounted on the surface where the optical waveguide 6 is not provided.

The electronic semiconductor element 7 is housed in a cavity 8 provided on the surface of the insulating substrate, and the electronic semiconductor element 7 is mounted on the alumina sintered body 1d by ball mounting using solder or the like and / or bare chip mounting. Mounted on the surface. In addition, since the cavity 8 is hermetically sealed by the lid 9 and has a structure in which outside air does not enter the inside of the cavity 8, malfunction of the electronic semiconductor element 7 can be prevented, and reliability can be improved.

External connection terminals 10 are provided on the surface of the dielectric layer 2. The external connection terminal 10 is for inputting a high frequency from the outside, and is electrically connected to an external circuit. Since the external connection terminal 10 is formed on the dielectric layer 2 having a low dielectric constant, stray capacitance generated between the external connection terminal 10 and the internal conductor layer 3b is reduced, reflection of an input signal is suppressed, and signal loss is suppressed. As a result, it is possible to realize an optoelectronic mounting circuit board capable of supporting a high frequency.

The insulating layer 1 is composed of an alumina sintered body obtained by sintering a molded body mainly composed of alumina and having a desired sintering additive added thereto, and is made of a single or a plurality of alumina sintered bodies.
In order to increase the mounting density, it is preferable to use a plurality of laminated alumina sintered bodies. Further, it is preferable to contain silica and Mn ₂ O ₃ as a sintering aid. These sintering aids enable sintering at a low temperature, prevent the conductor layer 3 from flowing out due to melting of metal, and increase the product yield. It is desirable that components other than alumina, such as a sintering aid, exist as an amorphous phase or a crystal phase at the grain boundary of the alumina main crystal phase.

According to the present invention, the alumina sintered body of the insulating layer 1 preferably has a relative density of 95% or more, especially 97% or more, and more preferably 98% or more in order to increase the thermal conductivity and strength of the insulating substrate. And a thermal conductivity of 10 W / m · K or more, especially 15
It is desirably at least W / m · K, and more preferably at least 17 W / m · K.

The main crystal phase of the alumina-based sintered body forming the insulating layer 1 exists as granular or columnar crystals, and the average crystal grain size of these main crystal phases is 1.5 to 5 μm.
It is desirable that When the main crystal phase is composed of columnar crystals, the average crystal grain size is based on the minor axis diameter. When the average crystal grain size of the main crystal phase is smaller than 1.5 μm, high thermal conductivity tends to be difficult. When the average crystal grain size is larger than 5 μm, sufficient strength required for use as a substrate material is obtained. This is because it tends to be difficult to obtain.

If the dielectric layer 2 has a dielectric constant lower than that of alumina, it is possible to reduce the signal input loss, which is the object of the present invention. In particular, among the mullite, forsterite, enstatite, silica, and cordierite, A sintered body containing at least one type as a main component is preferable from the viewpoint of simultaneous sintering with alumina. Other than this, as other components, Mn ₂ O ₃ , SiO ₂ , ZnO, CaO, Nb ₂ O ₅ ,
MoO ₃ , WO ₃ or glass may be added. Further, it is possible to contain 10% by weight or less of glass, but in order to achieve high strength of the substrate, 10% by weight or less,
In particular, the content is desirably 5% by weight or less.

The conductor layer 3 is made of Au, A
It is preferable to include at least one of g, Cu, and Pt. In order to improve the adhesion to alumina, W and / or
Or it is preferable to contain Mo. For example, if Cu is
70% by volume, and a composition containing 30 to 90% by volume of W and / or Mo.

The sheet resistance of the conductor layer 3 is equal to the conductor thickness 1
It is preferably 8 mΩ / □ or less in terms of 5 μm. By having such a low sheet resistance, the wiring width can be reduced, and the size can be reduced.

Next, a method of manufacturing an optoelectronic circuit board according to the present invention will be described.

First, in order to produce the insulating layer 1, alumina powder and a desired sintering aid powder are prepared. As the alumina raw material powder, the average particle size is 0.5 to 2.5 μm, particularly 0.1 μm.
A powder of 5 to 2.0 μm is used. This is because if the average particle size is smaller than 0.5 μm, it is difficult to handle the powder, and the cost of the powder becomes high. If the average particle size is larger than 2.5 μm, it becomes difficult to fire at a temperature of 1500 ° C. or less. It is.

As the second component, Mn ₂ O ₃ powder was added in the amount of 2 to 1
5 wt%, and the SiO ₂ powder is added in a proportion of 2 to 15 wt%. Mn ₂ O ₃ densification at 1200 to 1500 ° C. by the addition of the Mn compound powder such as a powder is promoted, also, it is possible to maintain a high insulating property, promotes densification by the addition of SiO ₂ powder, high thermal Can maintain conductivity. In addition, if necessary, Mg, C
a, containing at least one of oxides, carbonates, and hydroxides of Sr, B, Nb, Cr, and Co in an amount of 0.1 to 4% by weight in order to enhance co-sinterability with a Cu-containing conductor. As a fourth component, a metal powder or an oxide powder of a transition metal such as W, Mo, or Cr is added as a coloring component at a ratio of 2% by weight or less in terms of metal.

On the other hand, the dielectric layer includes at least one main component powder selected from mullite, forsterite, enstatite, silica, and cordierite, and Mn ₂ O ₃ , SiO ₂ , ZnO as the second component. , CaO, Nb ₂ O ₅ ,
At least one of MoO ₃ and WO ₃ and 10% by weight or less of glass as a third component can be added. By adding 10% by weight or less of glass,
The sinterability can be improved while suppressing the deformation of the low dielectric constant layer during firing and the decrease in thermal conductivity due to diffusion into the alumina layer.

Here, the particle diameter of the main component powder is 0.5 to
A powder of 5 μm, especially 0.5 to 3 μm is used. this is,
If the particle size is larger than 5 μm, cracks occur in the sintered particles and the strength is significantly reduced. Also,
If the thickness is smaller than 0.5 μm, it becomes difficult to handle the powder. In addition to the oxide powder, the oxide may be added as a carbonate, nitrate, acetate, or the like capable of forming an oxide by firing.

Then, a sheet-like molded body for forming an insulating layer is prepared using each mixed powder. The sheet-shaped molded body can be produced by a well-known molding method. For example, after a slurry is prepared by adding an organic binder or a solvent to the mixed powder, a sheet is formed by a doctor blade method, or an organic binder is added to the mixed powder, and a sheet having a predetermined thickness is formed by press molding, rolling, or the like. Body can be made. And for this sheet-like molded body,
The through holes for via-hole conductors may be formed by a microdrill, laser, or the like.

Next, the conductor layer is made of a low-resistance metal (Au, A
g, Cu, Pt) and the high melting point metal (W, Mo) so that the conductor paste contains at least Au powder, Ag powder,
It preferably contains at least one of Cu powder and Pt powder, and more preferably contains W powder and / or Mo powder.
For example, Cu powder and W powder, Au and Mo powder, etc.
As a specific example, Cu contains 10 to 70% by volume of 1 to 10 μm, particularly 30 to 60% by volume, and W and / or Mo of 1 to 10 μm in a ratio of 30 to 90% by volume and 40 to 70% by volume. Prepare a conductor paste. A metal such as Cu contributes to low resistance, and a high-melting-point metal prevents separation of the conductor layer due to a difference in thermal expansion coefficient from the insulating layer 1 and has a firing temperature higher than the melting point of Cu. Also functions as a shape-retaining agent.

The conductor paste desirably contains at least one of Ni, Zr, Al, Li, Mg, and Zn in an amount of 0.05 to 3.0% by weight in terms of a metal element. This is to reduce the resistance of the conductor layer, improve the simultaneous sinterability with the insulating substrate, and maintain the shape retention of the conductor layer after the simultaneous firing. Note that Ni,
Zr, Al, Li, Mg and Zn are oxides, borides,
It may be added as a nitride or a carbonate, and the average particle size at this time is 0.6 to 4 μm, particularly 1.5 to 3.0 μm.
Is desirable.

In the present invention, the resistance of the conductor layer
From the viewpoint of separation of the Cu component, bleeding, etc., the W powder and / or the Mo powder have an average particle size of 1 to 10 μm, particularly 1.3 to 5 μm.
It is also important to prepare m or, more preferably, 1.3 to 3 μm spherical or sintered particles of several particles so as to be dispersed in a matrix made of Cu.

In these conductor pastes, in order to enhance the adhesion to the insulating layer, alumina powder or a powder of the same composition as the oxide ceramic component forming the insulating layer is used in an amount of 0.04.
It is also possible to add at a ratio of 5 to 2% by volume.

Next, the above-mentioned conductive paste is applied to each of the insulating layers 1.
A conductor layer 3 is formed by printing and coating on a to 1d by a method such as screen printing or gravure printing. Also, the insulating layer 1
The above-mentioned conductive paste is filled in the via holes provided in a to 1d to form a via-hole conductive layer 3d.

Thereafter, the sheet-like molded body filled with the conductive paste is aligned and pressed by lamination, and the laminated body is fired in a non-oxidizing atmosphere at a maximum firing temperature of 1 ° C.
The firing is performed under the condition of a temperature of 200 to 1500 ° C.

If the firing temperature at this time is lower than 1200 ° C., the alumina insulating substrate cannot be densified to a relative density of 95% or more when ordinary raw materials are used. Densification of the dielectric layer cannot be achieved. On the other hand, if the sintering temperature is higher than 1500 ° C., sintering of W or Mo itself proceeds, and a uniform structure cannot be maintained due to the flow of Cu, and it is difficult to maintain low resistance at all. Preferably, the range of 1250-1400 degreeC is good.

It is preferable that the non-oxidizing atmosphere at the time of firing is nitrogen or a mixed atmosphere of nitrogen and hydrogen. In particular, in order to suppress the diffusion of Cu in the conductor layer, hydrogen and hydrogen are used. A non-oxidizing atmosphere containing nitrogen and having a dew point of + 30 ° C. or lower, particularly 0 to 25 ° C. is desirable. Note that an inert gas such as an argon gas may be mixed into this atmosphere, if desired. If the dew point during firing is higher than + 30 ° C., the conductive material reacts with moisture in the atmosphere during firing to form an oxide film, and the insulating layer reacts with Cu of the Cu-containing conductor to reduce the resistance of the conductor. Not only hinders
This is because it promotes the diffusion of u.

Further, in the insulating substrate of the present invention, C
By simultaneous firing at a temperature exceeding the melting point of u, the Cu component in the surface conductor layer 3a and the internal conductor layer 3b may diffuse into the insulating layer 1 and the dielectric layer 2, but according to the present invention,
The diffusion distance of Cu into the ceramics of the insulating substrate around the conductor layer containing at least Cu is 20 μm or less, particularly 1 μm.
It is desirable that the thickness be 0 μm or less. This is because if the diffusion distance of Cu into the ceramics exceeds 20 μm, the insulation between the conductor layers decreases, and the reliability as a wiring board decreases.

As a method of forming an optical waveguide on the surface of the insulating substrate produced by the above method, a silica-based optical waveguide is formed on an alumina insulating layer by a sol-gel method, or a polyimide, polymethyl methacrylate, polycarbonate or the like is used. It is possible to form an optical waveguide using an organic material or to form an optical waveguide using a CVD method.

Further, the optical semiconductor element is placed on the alumina insulating layer, and is electrically connected to the conductor layer of the substrate.
It is also possible to bury it in the optical waveguide cladding. The optical waveguide is formed on the alumina insulating layer because the optical waveguide forming layer has high strength and the coefficient of thermal expansion of the element optically connected to the optical waveguide is close to that of alumina, resulting in excellent connection reliability. This is because the semiconductor element has excellent heat conductivity against heat generation.

The electronic semiconductor element is desirably mounted on a surface having alumina as an insulating layer. This is because alumina has a relatively high thermal conductivity unlike glass ceramic or the like, so that heat generated from the element can be efficiently and quickly dissipated. Further, unlike a resin substrate such as polyimide, the coefficient of thermal expansion is close to that of a semiconductor element, so that high primary mounting reliability can be secured. At this time, the semiconductor element can be mounted on the substrate by ball mounting using solder or / and bare chip mounting.

Further, in the mounting board of the present invention, an electronic circuit including a capacitor, a resistor and a wiring conductor is formed on the surface of a mother board such as a printed board, and the opto-electronic mounting circuit board is connected via external connection terminals 10. Is implemented in electronic circuits. According to the present invention, by using the mounting board having the above configuration as the optoelectronic mounting circuit board, the reflection loss when a 40 GHz high-frequency signal is input to the optoelectronic mounting circuit board is -10.0 dB or less, especially -7 dB or less. -5 dB or less. Therefore, by using the optoelectronic mounting circuit board of the present invention, 40 GHz
The above high-frequency signal can be input, and large-capacity optical communication can be supported.

[0056]

EXAMPLE An alumina powder (average) was used to form an insulating layer.
Particle size 1.8 μm), Mn _TwoO_ThreeAnd SiO_TwoTo
6% by weight and 0.5% by weight of MgO
And an acrylic resin as an organic resin for the binder.
Slurry by adding toluene binder and toluene
After that, a 250 μm thick sheet is
It was molded into a shape.

In order to form a dielectric layer, at least one selected from mullite, forsterite, enstatite, silica and cordierite is used as a main component,
The additives shown in Table 1 were added to produce a sheet-like molded body. Here, the dielectric constant of the dielectric layer was adjusted by adjusting the amount of silica. And the hole diameter after firing is 100 to 2 at a predetermined location.
A via hole of 00 μm was formed.

Next, Cu powder having an average particle size of 5 μm, Ag
Powder, Au powder and Pt powder, and W powder or Mo powder having an average particle diameter of 0.8 to 12 μm are mixed at a ratio shown in Table 1, and a conductive paste is mixed with an acrylic binder using acetone as a solvent. Was prepared.

Then, the above-mentioned conductor paste was applied by printing on the sheet-like molded body, and the above-mentioned conductor paste was filled also into the via-hole conductor layer of each sheet-like molded body. Each sheet-like molded body produced as described above was aligned, laminated and pressed to produce a molded body laminate. Thereafter, the molded product laminate is placed in an oxygen-containing atmosphere (H ₂ +
After degreasing with O ₂ ), it was baked at 1300 ° C. in a mixed atmosphere of nitrogen and hydrogen at a dew point of 20 ° C., to obtain the optoelectronic mounted circuit board of FIG.

The density of the obtained substrate was measured by the Archimedes method. Further, the electric resistance (in terms of sheet resistance) of the conductor layer on the circuit board was measured by a four-terminal method. further,
The relative dielectric constant was measured at a measurement frequency of 40 GHz by the cavity resonator method based on JIS R1627.

The reflection loss was measured at 40 GHz using a network analyzer and a wafer probe. More specifically, as shown in FIG. 2, a mother board 22 for mounting the optoelectronic mounting circuit board 21 and the optoelectronic mounting circuit board 2
The value between the measurement electrodes provided in 1 was measured. The cross-sectional configuration of the measurement sample at this time. The thickness of each of the dielectric layer and the insulating layer forming the external connection terminals on the surface was 0.25 mm, and the via diameter was 0.1 mmφ. The diameter of the electrode pad (ball pad) constituting the external connection terminal is 0.4 mm.
φ, solder ball diameter 0.3mmφ, ball pitch 0.8
A Teflon (registered trademark) substrate having a thickness of 0.2 mm and a dielectric constant of 3.5 was used as a mother board on which the optoelectronic mounting circuit board was mounted.

The flexural strength of the ceramic layer was measured at three points using a simultaneously fired sample in which the thickness of the low dielectric constant insulating layer used for the external electrode forming layer was 0.5 mm and the thickness of the insulating layer other than the insulating layer was 2.5 mm. The bending strength was measured. Further, the thermal conductivity of the ceramic layer was measured at room temperature by a laser flash method using a sample having a laminated structure used for bending strength measurement.

[0063]

[Table 1]

Sample No. of the present invention In Nos. 2 to 18, the dielectric constant of the dielectric layer was 4.4 to 8, which was smaller than 9 of alumina of the insulating layer, and the reflection loss was -10 dB or less.

On the other hand, Sample No. 1 in which the insulating layer and the dielectric layer were made of the same material. Sample No. 1 had a reflection loss of -6.4 dB.

In the case of Sample No., in which the conductor layer is made of W or Mo and is outside the scope of the present invention. 19 and 20 have a sheet resistance of 2
The reflection loss was as large as 8 mΩ / □ or more, and the reflection loss was as large as −6.5 dB.

[0067]

According to the present invention, there is provided an optoelectronic mounting circuit board comprising an optical waveguide formed on an insulating layer surface of an insulating substrate provided integrally with an alumina insulating layer having excellent mechanical and thermal characteristics and a dielectric layer having a low dielectric constant. , An optical semiconductor element and an electronic semiconductor element are mounted, and external connection terminals are formed on the dielectric layer, thereby improving the reflection loss and insertion loss of a high-frequency input signal, thereby achieving a highly reliable and small optoelectronic mounting circuit board. Can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an optoelectronic mounting circuit board of the present invention.

FIG. 2 is a schematic sectional view showing a part of a mounting board of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating layer 1a, 1b, 1c, 1d ... Alumina sintered body 2 ... Dielectric layer 3 ... Conductor layer 3a ... Surface conductor layer 3b ... Inner conductor layer 3c ... -Ground conductor layer 3d-Via hole conductor layer 5-Optical semiconductor element and / or optoelectronic semiconductor element 6-Optical waveguide 6a-Optical waveguide core 6b-Optical waveguide clad 7-Electronic semiconductor Element 8: Cavity 9: Lid 10: External connection terminal

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) H01L 23/12 DF F term (reference) 2H047 KB09 MA07 QA07 5E338 AA03 AA18 BB03 CC10 EE02 EE14 EE22 5E346 AA12 AA13 BB02 CC17 CC21 CC32 CC35 CC36 CC38 CC39 DD34 DD45 EE24 FF18 GG04 GG06 GG08 GG09 GG15 GG19 HH06 HH22

Claims (11)

[Claims] An insulating layer comprising an alumina sintered body and a dielectric layer having a lower dielectric constant than the insulating layer are integrally laminated, and Au, Ag, Cu, and the like are formed on the surface and / or inside. Pt
An insulating substrate on which at least one kind of conductor layer is formed, an optical waveguide and an optical semiconductor element mounted on one surface side of the insulating substrate, and an electron mounted on one or the other surface of the insulating substrate. An optoelectronic mounting circuit board, comprising: a semiconductor element; and external connection terminals provided on the dielectric layer of the insulating substrate. 2. The optoelectronic mounted circuit board according to claim 1, wherein said insulating layer and / or said dielectric layer comprises a laminate. 3. The optoelectronic mounting circuit board according to claim 1, wherein the electronic semiconductor element and the optical semiconductor element are mounted on opposing surfaces of the insulating substrate. 4. The semiconductor device according to claim 1, wherein an electronic semiconductor element is accommodated in a cavity provided on a surface of said insulating substrate, and said cavity is hermetically sealed by a lid. The optoelectronic mounting circuit board according to any one of the above. 5. The optoelectronic mounting circuit board according to claim 1, wherein said dielectric layer of said insulating substrate is formed on a part of a surface of said insulating layer. 6. The optoelectronic circuit board according to claim 1, wherein said optical semiconductor element is provided inside said optical waveguide. 7. The dielectric layer according to claim 1, wherein said dielectric layer is a sintered body containing at least one of mullite, forsterite, enstatite, silica and cordierite as a main component. The optoelectronic mounting circuit board according to any one of the above. 8. The method according to claim 1, wherein the alumina sintered body is made of silica and Mn _2.
Optoelectronic mounting circuit board according to any one of claims 1 to 7, characterized in that it contains O _3. 9. The optoelectronic circuit board according to claim 1, wherein said conductor layer contains W and / or Mo. 10. A sheet resistance of said conductor layer is 15 conductor thickness.
The optoelectronic mounting circuit board according to claim 1, wherein the value is 8 mΩ / □ or less in terms of μm. 11. An electronic circuit including a capacitor, a resistor, and a wiring conductor is formed on a surface of a mother board, and the optoelectronic mounting circuit board according to claim 1 is connected via an external connection terminal. 4 mounted on the electronic circuit
A mounting board, wherein a reflection loss when a high frequency signal of 0 GHz is input to the optoelectronic mounting circuit board is -10.0 dB or less.