JP3131191B2 - High frequency porcelain composition and high frequency porcelain - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board applied to a package for storing semiconductor elements, a multilayer wiring board, and the like, and more particularly to a wiring board which can be co-fired with copper or silver. High frequency porcelain compositions and high frequency porcelain that can be mounted with high reliability on external circuit boards made of organic resin such as chip parts and printed boards, and are used as insulating substrates in wiring boards.
And its manufacturing method.

[0002]

2. Description of the Related Art Conventionally, as a ceramic multilayer wiring board, a ceramic multilayer wiring board in which a wiring layer made of a refractory metal such as tungsten or molybdenum is formed on the surface or inside of an insulating substrate made of an alumina-based sintered body has been most widely used. I have.

Further, recently, with the era of advanced information, the frequency band to be used is shifting to higher and higher frequencies. In such a high-frequency wiring board that requires transmission of a high-frequency signal, in order to transmit a high-frequency signal without loss, the resistance of the conductor forming the wiring layer is small, and the dielectric of the insulating substrate in the high-frequency region is low. Low loss is required.

However, conventional tungsten (W),
Refractory metals such as molybdenum (Mo) have high conductor resistance, have low signal propagation speeds, and have difficulty in signal propagation in the high-frequency region of 1 GHz or higher. It is necessary to use low resistance metals such as silver and gold. Since the wiring layer made of such a low-resistance metal has a low melting point and cannot be co-fired with alumina, recently, a so-called glass ceramic made of glass or a composite material of glass and ceramic has been insulated. Wiring boards used as substrates are being developed. For example, as disclosed in Japanese Patent Application Laid-Open No. 60-240135, a multilayer wiring board in which a filler such as Al ₂ O ₃ , zirconia, and mullite is added to a zinc borosilicate glass and co-fired with a low-resistance metal, 5-298
As in Japanese Patent No. 919, a glass ceramic material in which mullite or cordierite is precipitated as a crystal phase has been proposed.

Further, when mounting chip parts such as GaAs on a wiring board such as a multilayer wiring board or a package for housing semiconductor elements, or mounting a wiring board on a printed board containing an organic resin such as a motherboard, an insulating board is required. In order to prevent the mounting part from peeling or cracking due to the stress generated due to the thermal expansion difference between the chip part and the printed circuit board, the thermal expansion coefficient of the It is desired to be close to that of

Therefore, the present applicant has previously disclosed in Japanese Patent Laid-Open No. 9-17 / 1997.
As disclosed in Japanese Patent No. 904, it has been proposed that the use of crystallizable lithium silicate glass can increase the thermal expansion coefficient of an insulating substrate.

[0007]

However, the conventional glass ceramic has a thermal expansion coefficient of 3 to 5 even if it can be co-fired with a low-resistance metal such as copper, silver or gold.
ppm / ° C, which is as low as about 1 ppm / ° C, the reliability of mounting when mounting chip parts such as GaAs (coefficient of thermal expansion: 6 to 7.5 ppm / ° C) or printed circuit boards (coefficient of thermal expansion: 12 to 15 ppm / ° C) The properties were low and were not practically satisfactory.

In the method using a glass containing an alkali metal as disclosed in Japanese Patent Application Laid-Open No. Hei 9-17904, when exposed to a high-temperature and high-humidity atmosphere for a long time, the alkali metal reacts with the moisture in the atmosphere to produce a surface. In some cases, a silicate crystal phase is precipitated and the surface is deteriorated.

Conventional glass ceramics have not been specifically studied as insulating substrates for wiring boards using high-frequency signals such as millimeter waves, and most of them have high dielectric loss and have satisfactory high-frequency characteristics. Was not.

Therefore, the present invention can be fired at 800 to 1000 ° C., which can be multilayered using gold, silver and copper as wiring conductors, and has a thermal expansion coefficient close to that of chip parts such as GaAs or a printed circuit board. It is an object of the present invention to provide a porcelain which can be controlled to the above-mentioned coefficient of thermal expansion, has a low dielectric constant and a low dielectric loss even in a high frequency region, a method for producing the same, and a high frequency porcelain composition which can be produced therefrom.

[0011]

Means for Solving the Problems As a result of diligent studies on the above-mentioned problems, the present inventors have found that glass powder containing SiO ₂ , Al ₂ O ₃ , MgO and CaO and capable of precipitating a diopside oxide crystal phase. On the other hand, a composition in which amorphous silica powder was blended at a specific ratio was used.
By sintering at a temperature of 0 to 1000 ° C., it has a low dielectric constant and a thermal expansion coefficient close to that of a chip component such as GaAs or a printed circuit board, and a low dielectric loss even in a high frequency region of 1 GHz or more. It has been found that a porcelain having the following formula is obtained, and the present invention has been achieved.

That is, the high-frequency ceramic composition of the present invention has
It contains iO ₂ , Al ₂ O ₃ , MgO, SrO and CaO, and contains 50 to 95% by weight of glass capable of precipitating a diopside oxide crystal phase and 5 to 50% by weight of amorphous silica. It is characterized by the following.

The glass is made of SiO ₂ 45-55.
%, Al ₂ O ₃ 3 to 10% by weight, and MgO 13 to 2
4% by weight, 10 to 24% by weight of SrO, 8 to 2% of CaO
Desirably, it is 0% by weight.

Further, the high frequency porcelain of the present invention contains a diopside oxide crystal phase containing at least Mg, Ca, Si and Al, and an amorphous silica phase, and has a thermal expansion coefficient from room temperature to 400 ° C. 5.5 ppm / ° C. or higher, dielectric constant of 7 or lower, particularly 5.9 or lower, 60 to 77 GH
The dielectric loss at z is 30 × 10 ⁻⁴ or less.

[0015]

[0016]

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The high frequency porcelain composition of the present invention comprises:
Glass containing SiO ₂ , Al ₂ O ₃ , MgO, SrO and CaO and capable of precipitating a diopside-type oxide crystal phase, and containing 50 to 95% by weight of amorphous silica and 5 to 50% by weight of amorphous silica. Things.

The reason for limiting each component composition to the above range is as follows.
If the content of the glass is less than 50% by weight, it is difficult to densify the porcelain by firing at a temperature of 1000 ° C. or less, and if the content is more than 95% by weight, the crystallization of the glass becomes insufficient, and the dielectric loss becomes large. This is because a large glass phase remains and the dielectric loss of the porcelain at high frequencies increases. A particularly desirable range for the glass is 60-85% by weight.

If the amount of the amorphous silica is less than 5% by weight, the residual ratio of the glass increases and the dielectric loss increases. Conversely, if it exceeds 50% by weight, sintering becomes difficult, and
It cannot be densified at a firing temperature of 000 ° C. or lower.
A desirable range of the amorphous silica is 15 to 40% by weight.

Here, the glass capable of precipitating the diopside oxide crystal phase has a glass softening point of 500-8.
00 ° C., and the composition is SiO ₂ 45
55 wt%, Al ₂ O ₃ 3~10 wt%, MgO13
-24% by weight, SrO 10-24% by weight, CaO 8-2
Desirably, the proportion is 0% by weight.

In order to increase the precipitation ratio of the diopside oxide crystal phase from the above glass, the total amount of CaO and MgO in the glass is desirably 35 to 44% by weight.

To manufacture the high frequency porcelain of the present invention, S
Using a mixed powder of a crystallized glass containing iO ₂ , Al ₂ O ₃ , MgO, SrO and CaO and capable of precipitating a diopside-type oxide crystal phase, and the above-mentioned composition comprising amorphous silica, a doctor blade method, After producing a molded body of a predetermined shape by a known molding method such as a calender roll method, a rolling method, or a press molding method, the molded body is 800 to
It can be manufactured by firing at 1000 ° C. in an oxidizing atmosphere or a non-oxidizing atmosphere.

According to the present invention, the use of the above glass composition makes it possible to use a glass material having a high melting point such as SiO ₂ as a filler, at a temperature of 1000 ° C. or less, particularly 950 ° C. or less, and even 930 ° C. Since firing at a temperature of not more than ° C. is possible, simultaneous firing with copper and / or silver, which is frequently used as a wiring layer of a high-frequency wiring board, as described later, is possible.

Here, when quartz is added, it may be transformed into cristobalite, tridymite or the like by sintering in addition to quartz.
Since it has a bending point of the thermal expansion coefficient near 00 ° C., it is desirable that the thermal expansion coefficient and the dielectric properties remain as quartz.

The porcelain composition of the above embodiment has a composition of 800 to 10
By sintering in a temperature range of 00 ° C., the density can be reduced to a relative density of 97% or more, and the overall composition of the porcelain formed thereby is calculated based on oxides of metal elements of Si, Al, Mg and Ca. when the total amount is 100 wt%, a SiO ₂ 55 to 75 wt%, the Al ₂ O _3. 3 to
5% by weight, 10-14% by weight of MgO, 15-% of SrO
It is desirable that the composition be composed of 23% by weight and 14 to 19% by weight of CaO.

Generally, the glass phase containing Al ₂ O ₃ or SiO ₂ has a low thermal expansion coefficient of 4 to 5 ppm / ° C. On the other hand, the diopside oxide crystal phase of Ca (Mg, Al) (Si, Al) ₂ O ₆ has a high thermal expansion characteristic of about 8 to 9 ppm / ° C. High thermal expansion can be achieved by precipitating a pside oxide crystal phase. The diopside oxide crystal phase is a material having a dielectric constant of 6 to 8 and having a small dielectric loss in a high frequency band.

According to the high frequency porcelain composition of the present invention, glass and amorphous silica (coefficient of thermal expansion of 2 to 5 pp)
m / ° C.), the coefficient of thermal expansion, the dielectric constant, and the like can be arbitrarily adjusted.

The presence of the amorphous silica phase in the above-described high frequency porcelain allows the thermal expansion coefficient from room temperature to 400 ° C. to be 5.5 ppm / ° C. or more and the permittivity to be 7 or more.
Hereinafter, the dielectric loss at 60 to 77 GHz can be controlled to a characteristic of 30 × 10 ⁻⁴ or less.

According to the present invention, by adding quartz as a filler to the glass having the above composition, a diopside oxide crystal phase is precipitated in the porcelain and a high thermal expansion of 13 to 20 ppm / ° C. By including a quartz crystal phase having a coefficient, the thermal expansion coefficient of the porcelain can be increased to 8.5 ppm / ° C. or more. As a result, the difference in the coefficient of thermal expansion between the porcelain and an external circuit board made of an organic resin such as a chip component such as GaAs and a printed board can be reduced. Therefore, when the porcelain of the present invention is used as an insulating substrate of a wiring board, the reliability of mounting is reduced. Can be enhanced.

Further, since the dielectric constant of quartz is 4 to 4.5, the dielectric constant of porcelain can be reduced to 7 or less.
Since the influence of the substrate on the high-frequency signal can be reduced and quartz is a material having a small dielectric loss in the millimeter wave band, the dielectric loss of porcelain at 60 to 77 GHz is reduced by 30 × 1.
Since it can be 0 ^-4 or less, signal transmission characteristics in a high frequency band, particularly in a millimeter wave band, are improved.

As shown in the schematic diagram of the porcelain structure shown in FIG. 1, the porcelain produced as described above has a dioptric phase containing at least Mg, Ca, Si and Al precipitated from glass as a crystal phase. Side-type oxide crystal phase Ca (M
g, Al) (Si, Al) ₂ O ₆ (DI)
It contains an O ₂ -based phase (Si, AM), and additionally contains Ca ₂ MgSi ₂ O ₇ (akermanit).
e), CaMgSiO ₄ (monticellit)
e), similar phases with high thermal expansion, such as Ca ₃ MgSi ₂ O ₈ (merwinite), may precipitate.

Further, according to the present invention, by adding mainly amorphous silica as a filler to the glass having the above composition, a diopside oxide crystal phase is precipitated in the porcelain, and the grain boundary is reduced to an amorphous phase. Since the dielectric constant of amorphous silica is as low as 3.8 to 4.2 by being mainly formed by the silica phase,
The dielectric constant of the porcelain can be 5.9 or less, and when used for a high-frequency wiring board or the like, the influence of the board on transmission characteristics of high-frequency signals can be reduced. Furthermore, since amorphous silica is a material having a small dielectric loss in a millimeter wave band, the dielectric loss of porcelain at 60 to 77 GHz can be reduced to 30 × 10 ⁻⁴ or less.

The porcelain composition of the present invention has a low dielectric loss in a high frequency band, and therefore has a dielectric loss of 1 GHz or more, particularly 20 GHz or more, more preferably 50 GHz or more, and even 70 GHz.
It is suitable for forming the insulating layer of the high-frequency wiring board described above. When using the porcelain of the present invention as an insulating substrate of a wiring board, in order to reduce the effect on the transmission characteristics of high-frequency signals,
It is desirable that the dielectric constant is as low as 7 or less, particularly as low as 5.9 or less.

In this case, as described above, the thermal expansion coefficient of the insulating substrate from room temperature to 400 ° C. is similar to the thermal expansion coefficient of a mounted chip component or a printed circuit board.
It is desirable that the composition and structure of the porcelain constituting the substrate be controlled and appropriately adjusted.

When the thermal expansion coefficient of the insulating substrate is different from that of the mounted chip component or the printed circuit board, the temperature of the chip component or the like is increased by repeated temperature cycles during solder mounting or by stopping the operation of the semiconductor element. This is because stress due to the difference in thermal expansion is generated in the mounting portion between the printed circuit board and the package, and cracks and the like are generated in the mounting portion, thereby impairing the reliability of the mounting structure.

More specifically, the difference between the thermal expansion coefficient of the GaAs-based chip component and that of the GaAs-based chip component is 2 ppm / ° C. or less. In this case, it is desirable that the difference in the coefficient of thermal expansion from the printed circuit board is 2 ppm / ° C. or less.

Specifically, a method of manufacturing a wiring board having a wiring layer using the high-frequency ceramic composition of the present invention will be described. A slurry is prepared by mixing a mixed powder of the above-described composition with an appropriate organic solvent and a solvent, and the slurry is formed into a sheet by a conventionally known doctor blade method, calender roll method, or rolling method, press molding method. Mold into Then, after forming a through hole as desired in the sheet-like molded body, in the through hole,
A metal paste containing at least one of copper, gold, and silver is filled. Then, on the surface of the sheet-shaped molded body, the metal paste is used to form a high-frequency line pattern or the like that can transmit a high-frequency signal by screen printing, gravure printing, or the like so that the thickness of the wiring layer is 5 to 30 μm. Apply.

Thereafter, a plurality of sheet-like molded bodies are aligned, laminated and pressed, and fired in a non-oxidizing atmosphere such as a nitrogen gas or a nitrogen-oxygen mixed gas at 800 to 1000 ° C. to produce a wiring board. be able to. Then, a chip component such as a semiconductor element is appropriately mounted on the surface of the wiring board, and connected to the wiring layer so that signals can be transmitted.

As a connection method, a connection may be made by directly mounting on a wiring layer, or a resin, Ag
-The chip component is fixed to the surface of the insulating substrate with an adhesive such as a resin such as epoxy, Ag-glass, or Au-Si, a metal, or a ceramic, and the wiring layer and the semiconductor element are connected by wire bonding or TAB tape.

As the semiconductor element, a chip component such as a Si-based or GaAs-based chip can be used, but it is most effective for mounting a GaAs-based chip component in terms of the similarity of the thermal expansion coefficient.

Further, a cap made of an insulating material of the same kind as the insulating substrate, another insulating material, or a metal having a good heat radiation property and having an electromagnetic wave shielding property is provided on the surface of the wiring board on which the semiconductor element is mounted by using glass, The semiconductor element may be hermetically sealed by bonding with an adhesive such as a resin or a brazing material.

A specific structure of a package for housing a semiconductor element, which is an example of a high-frequency wiring board in which the ceramic composition of the present invention can be preferably used, and a mounting structure thereof will be described with reference to FIG. FIG. 2 is a schematic sectional view of a semiconductor storage package, particularly a ball grid array (BGA) type package in which connection terminals are formed of ball-shaped terminals.

According to FIG. 2, the package A has a cavity 3 formed by an insulating substrate 1 made of an insulating material and a lid 2, in which a chip component 4 such as GaAs is bonded. Implemented by agent.

Further, on the surface and inside of the insulating substrate 1,
A wiring layer 5 electrically connected to the chip component 4 is formed. The wiring layer 5 is desirably made of a low-resistance metal such as copper, silver, or gold in order to minimize conductor loss when transmitting a high-frequency signal. When transmitting a high-frequency signal of 1 GHz or more to the wiring layer 5, it is necessary to transmit the high-frequency signal without loss. Therefore, the wiring layer 5 includes a known strip line, microstrip line, coplanar line, It is composed of at least one of dielectric waveguide lines.

In the package A of FIG. 2, a connection electrode layer 6 is formed on the bottom surface of the insulating substrate 1 and is connected to the wiring layer 5 in the package A. A ball-shaped terminal 8 is formed on the connection electrode layer 6 with a brazing material 7 such as solder.

In order to mount the package A on an external circuit board, as shown in FIG. 2, wiring is formed on the surface of an insulating substrate 9 made of an insulating material containing an organic resin such as a polyimide resin, an epoxy resin, or a phenol resin. The external circuit board B on which the conductor 10 is formed is mounted via a brazing material. Specifically, the ball-shaped terminals 8 attached to the bottom surface of the insulating substrate 1 in the package A and the wiring conductors 10 of the external circuit board B are brought into contact with each other, and the brazing material 11 such as a solder such as Pb-Sn is used. It is mounted with brazing. Also,
The ball-shaped terminal 8 itself may be melted and connected to the wiring conductor 10.

According to the present invention, the chip component 4 such as GaAs is mounted on an external circuit board such as a printed board by brazing or mounting with an adhesive or by brazing such ball-shaped terminals 8. In such a surface mount type package, a thermal cycle is applied to such a mounting structure because a difference in thermal expansion between a chip component such as GaAs and an insulating substrate of an external circuit board can be made smaller than that of a conventional ceramic material. Also in this case, the generation of stress in the mounting portion can be suppressed, and as a result, the long-term reliability of the mounting structure can be improved.

[0048]

EXAMPLE A crystallized glass capable of precipitating two kinds of diopside oxide crystal phases having the following compositions was prepared.

Glass A: 50.2% by weight of SiO ₂ -5.0% by weight of Al ₂ O ₃ -16.1% by weight of MgO-13.6% by weight of SrO -15.1% by weight of glass B: 47.5% by weight of SiO ₂ % -Al ₂ O ₃ 4.9 wt% -MgO16.1 wt% -SrO20 wt% -CaO11.5 wt% Then, with respect to the crystallized glass powder, the average particle size of 5
Using quartz having a particle size of μm or amorphous silica powder having an average particle size of 2 μm, mixing was performed so that the compositions shown in Tables 1 and 2 were obtained. Then, an organic binder, a plasticizer, and toluene were added to the mixture to prepare a slurry.
m green sheets were produced. Then, 10 to 15 green sheets are laminated, and at a temperature of 50 ° C., 100 k
g / cm ² and a thermocompression bonding. The obtained laminate was subjected to a binder removal treatment in a steam-containing / nitrogen atmosphere at 700 ° C., and then fired in dry nitrogen under the conditions shown in Tables 1 and 2 to obtain a porcelain for an insulating substrate.

The obtained ceramics were evaluated for dielectric constant and dielectric loss by the following methods. The measurement is shape, diameter 2-7mm,
Cut out to 1.5-2.5mm thickness, 60GHz
, And a dielectric cylinder resonator method using a network analyzer and a synthesized sweeper. In the measurement, the dielectric resonator was excited by an NRD guide (non-radiative dielectric line), and the dielectric constant and the dielectric loss were calculated from the resonance characteristics of the TE021 and TE031 modes.

A thermal expansion curve from room temperature to 400 ° C. was taken to calculate a thermal expansion coefficient. Further, the main crystal phase in the sintered body was identified from the X-ray diffraction chart.
The results are shown in Tables 1 and 2.

For some of the samples, ZrO ₂ powder and CaZrO ₃ powder were used in place of quartz and / or amorphous silica as filler components, and porcelain was similarly prepared and evaluated (samples Nos. 19 to 21). , 35
~ 37). In addition, the same evaluation was performed using glass C having the following composition instead of the crystallized glasses A and B (Sample Nos. 38 and 39).

Glass C: SiO ₂ 10.4 wt% -Al ₂ O ₃ 2.5 wt% -B ₂ O ₃ 45.3 wt% -CaO 35.2 wt% -Na ₂ O 6.6 wt%

[0054]

[Table 1]

[0055]

[Table 2]

As is clear from the results in Tables 1 and 2, Si
Sample No. ₂ containing 95% by weight or more of glass containing O ₂ , Al ₂ O ₃ , MgO, SrO, and CaO. In Samples Nos. 1 and 14, the dielectric loss exceeded 30 × 10 ^-4 and the amount of glass was less than 50% by weight. In 2, 6, 10, 20
It was difficult to sinter at low temperatures and did not densify.
Sample No. Nos. 11 to 13 and 21 to 23 contain ZrO ₂ or CaZrO ₃ as an additive component to the glass. However, ZrO ₂ or CaZrO ₃ was precipitated in the sintered body and dielectric loss increased. Further, Sample No. using glass C containing a large amount of B ₂ O ₃ as glass was used. Sample No. 24 melts. In No. 25, a large amount of glass containing B remained and the dielectric loss tended to increase.

[0057]

According to the present invention, sample No. 1 containing a specific amount of amorphous silica powder was added. 3-5, 7-9, 15-1
In No. 9, an amorphous silica phase was present in the porcelain, and all had a thermal expansion coefficient of 5.5 ppm / ° C. or more,
At a measurement frequency of GHz, the dielectric constant was 7 or less, particularly 5.9 or less, and the dielectric loss was 30 × 10 ^-4 or less, which was excellent.

[0059]

As described above in detail, according to the porcelain composition for high frequency wave of the present invention, since it can be fired at a low temperature of 1000 ° C. or less, a wiring layer made of a low-resistance metal such as copper can be formed. In this high-frequency region, a low dielectric constant and a low dielectric loss allow a high-frequency signal to be transmitted very favorably and without loss.

Moreover, the porcelain obtained using this composition can be controlled to have a thermal expansion characteristic similar to that of a GaAs chip or a printed circuit board. Therefore, when a GaAs chip is mounted, or when a printed circuit provided with an insulating substrate containing an organic resin is used. It has excellent heat cycle resistance when mounted on a motherboard such as a board with brazing material,
A highly reliable mounting structure can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining the structure of porcelain obtained by firing a composition of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating an example of a mounting structure of a package for housing a semiconductor element, which is an example of a high-frequency wiring board using a porcelain obtained by firing the composition of the present invention.

[Explanation of symbols]

DI Diopside oxide crystal phase Si SiO ₂ crystal phase AM Amorphous silica phase G Amorphous (glass) phase A Package for storing semiconductor elements B External circuit board 1 Insulating substrate 2 Lid 3 Cavity 4 Chip component 5 Wiring layer 6 connecting electrode layer 7 brazing material 8 ball-shaped terminal 9 insulating substrate 10 wiring conductor 11 brazing material

Claims (4)

(57) [Claims] 1. A glass containing 50 to 95% by weight of SiO ₂ , Al ₂ O ₃ , MgO, SrO and CaO and capable of precipitating a diopside oxide crystal phase, and 5 to 50% by weight of amorphous silica. A high frequency porcelain composition, characterized in that it is contained in a proportion. 2. The method according to claim 1, wherein said glass is 45 to 55% by weight of SiO _2.
2. The high frequency ceramic composition according to claim 1, comprising: _{3 to} 10% by weight of Al2O3, 13 to 24% by weight of MgO, 10 to 24% by weight of SrO, and 8 to 20% by weight of CaO. object. 3. A composition comprising a diopside oxide crystal phase containing at least Mg, Ca, Si and Al, and an amorphous silica phase, and having a thermal expansion coefficient of 5.5 ppm / ° C. or more from room temperature to 400 ° C. Dielectric constant of 7 or less, 60-7
A high-frequency porcelain having a dielectric loss of 30 × 10 ⁻⁴ or less at 7 GHz. 4. The high frequency porcelain according to claim 3, wherein the dielectric constant is 5.9 or less.