JPS5988851A - Silicon carbide substrate for electronic circuit and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a circuit substrate of nearly the same coefficient of thermal expansion as Si and of excellent heat dissipating characteristic by a method wherein a ceramic thin plate whose volume specific resistance is over a specific value is joined with a layer containing a kind of oxide of Al and another fixed metal as the main component, on an SiC thin plate. CONSTITUTION:An oxide film 2 is formed by directly treating the SiC thin plate 1 in oxidizing atmosphere at 750-1,650 deg.C, or after covering it with a composition containing a kind of elements of Al, Si, P, B, Ge, As, Sb, Bi, V, Zn, Cd, Pb, Na, K, Li, Be, Ca, Mg, Ba, Sr, and Zr, or compound thereof. Next, cementing material 3 containing a kind of these elements or compound thereof is applied. The ceramic thin plate 4 of the main component of a kind of alumina, mullite, sillimanite, zirconia, steatite, spinel, forsterite, magnesia, titania, sialon Si3N4, and BN, thickness of 0.05mm., and volume specific resistance at 10<6>OMEGAcm is superposed, being treated at 250-1,200 deg.C and adhered 3 with two kinds or more of metallic oxides. This constitution enables to obtain a substrate excellent in electric insulation property and suitable for direct junction of an Si chip.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silicon carbide substrate for electronic circuits used as a substrate for integrated circuits or a material for engineered C packages, and a method for manufacturing the same. The present invention relates to a silicon carbide substrate for electronic circuits formed by bonding ceramic thin plates and a method for manufacturing the same.

2. Description of the Related Art In recent years, with the progress of electronic industrial technology, electronic devices are becoming more densely packed or have higher speed calculation functions. As a result, the amount of heat generated within the integrated circuit increases, resulting in a problem that it becomes difficult to ensure the performance of the integrated circuit and maintain high reliability. Therefore, electronic circuit boards used as integrated circuit boards or IC package materials are required to have excellent heat dissipation properties in addition to properties such as electrical insulation, airtightness, and mechanical strength.

By the way, various types of substrates for observation circuits have been known and put into practical use, and for applications that require particularly high reliability, alumina sintered substrates (hereinafter referred to as alumina sintered substrates) are mainly used. (simply referred to as alumina substrate) is used. However, alumina substrates have low thermal conductivity,
Due to poor dissipation characteristics of heat generated within the integrated circuit,
This is an extremely large obstacle in increasing the density of electronic devices and increasing the speed of calculation functions, and the coefficient of thermal expansion of alumina substrates is significantly different from that of silicon chips, which are normally used as integrated circuits. It is difficult to bond silicon chips directly onto a substrate.

In order to solve the problem in the dissipation characteristics of RjJ heat recording,
Conventionally, substrates using IJ IJ or enamel have been considered. However, the former beryllia substrate has the disadvantage of being difficult and expensive to manufacture and handle due to its toxicity, while the latter enamel substrate has a low thermal expansion coefficient because it uses a metal plate as a material. The enamel is large, the frit tends to form a dogbone structure, and it is difficult to cut after printing, as well as cracks form in the enamel, making laser trimming impossible.

In order to solve the above-mentioned drawbacks, tp￥Kaisho J'A
-A40gA publication states that ``Silicon carbide is the main component and 1~,
In addition, an invention relating to an "electrically insulating substrate made of a sintered body containing at least one of beryllium oxide and boron nitride" is disclosed. However, the electrical insulating substrate must be sintered using a hot press method, which is difficult and expensive to mass produce, and if it contains beryllium oxide, there are problems with the longevity of beryllium. are doing.

In addition, in order to apply silicon carbide sintered bodies as substrates for electronic circuits, the present inventors have conducted various studies on methods of imparting electrical insulation properties to silicon carbide sintered bodies, and have previously filed a patent application filed in 1973: 1
No. 0999/, the patent application No. 1983-1999 describes a ``silicon carbide substrate having an insulating surface coating with excellent adhesion that is mainly composed of a eutectic oxide of aluminum oxide and silicon dioxide'' and a method for manufacturing the same. Koθ? According to No. 99.2, “8102, P2O5, B2O3, G on the surface of silicon carbide sintered body
eO2, A3203, 5b203°B12o3. v2
o3. ZnO, pbo, pb3o, , pbo
2゜CdO, Na2O, K2O, Li2O, OaO, M
gO, BaO.

A silicon carbide substrate having an insulating film containing at least one selected from BrO/an oxide produced eutectically with rice as a main component, and a method for manufacturing the same, are also disclosed in patent application Sho S7-
According to No. 1g light g, [having a welding layer (a) as described in 1 on the silicon carbide substrate, and having a welding layer as described in F (on the welding layer (a))
(b) A silicon carbide substrate having an insulation resistance value of 3 x 10''Ω or more when the applied voltage is: l'; (b) Aluminum, silicon, phosphorus,
Boron, germanium, arsenic.

antimony, bismuth, vanadium, % lead, mium, lead, sodium, potassium, lithium.

A welding layer whose main component is at least one oxide selected from calcium, magnesium, barium, and strontium. ” and a method for producing the same.

By the way, silicon carbide substrates that have been given electrical insulation by forming a monoxide insulating film layer have semiconductor-like properties, and are less affected by dielectric constant than alumina substrates. Therefore, it is desired to increase the thickness of the oxide insulating film layer to reduce the capacitance. However, if the oxidized insulating film 1- is too thick, defects such as cracks are likely to occur due to the difference in coefficient of thermal expansion between the film layer and silicon carbide, and in some cases it may peel off. It was difficult to form an insulating film layer.

By the way, 't6, lead bins are generally provided on the child circuit board for connection with other circuit components.

Since a relatively large stress may be applied to the lead pin during handling, it is required to have a bonding strength that does not easily come off. However, since the stress is concentrated near the joint of the lead bin, when the lead bin is joined using an oxide insulating coating layer as described above, the bond often breaks from the bonding surface between the coating layer and silicon carbide, resulting in a strong bond. It has been difficult to provide lead pins with

An object of the present invention is to provide a silicon carbide substrate for electronic circuits that eliminates various drawbacks of conventionally known silicon carbide substrates, and a method for manufacturing the same. Thin plate is A! ,Si,
P, B, Ge, As, Sb.

Bi, V, Zn, Od, Pb, Na
, K., Li, Be.

A silicon carbide substrate for an electronic circuit, which is bonded to the surface of a silicon carbide thin plate by a bonding layer containing at least seven oxides selected from Oa, Mg, Ba, Sr, or Zr as a main component, and a method for manufacturing the same. The above objective can be achieved by:

Next, the present invention will be explained in detail.

The inventors of the present invention have repeatedly conducted various studies on the electrical insulation properties, electrostatic properties, and bondability of lead pins of the silicon carbide substrate, and as a result, a thin ceramic plate is bonded to a silicon carbide thin plate, and a laminated structure as shown in FIG. The present invention was completed based on the new finding that the above-mentioned drawbacks can be solved by adopting a new structure.

In other words, by creating a laminated structure in which a ceramic thin plate is bonded to a silicon carbide thin plate, the silicon carbide material has characteristics such as extremely stable electrical insulation, sufficiently low capacitance, and excellent bondability with lead pins. We have come up with ideas for what can be done with the substrate, and have obtained a silicon carbide substrate that has extremely excellent properties as a substrate for electronic circuits.

The silicon carbide substrate of the present invention has a silicon carbide thin plate with a
It is necessary to have a laminated structure formed by bonding ceramic thin plates having a specific volume resistivity of 6Ω or more.

The reason for this is that the silicon carbide substrate, which has a laminated structure in which a ceramic thin plate having a volume resistivity of θΩ1 or more is bonded to the surface of a silicon carbide thin plate, is reliable even under conditions of high applied voltage. This is because it has excellent electrical insulation, low capacitance, and excellent bondability with lead pins provided for connection with other circuit components. Also, the ceramic thin plate is /θ6
The reason why it is necessary to have a specific volume resistivity of Ωα or more is that although an electric circuit is usually provided on the silicon carbide substrate by means such as printing, baking, or etching, the volume of the ceramic thin plate is Specific resistivity is 70
If it is lower than 6Ω, it will not be possible to maintain electrical insulation and a short circuit will occur in one circuit, causing the circuit function to not work properly.If higher reliability is required, 1O8Ω Advantageously, it is a ceramic sheet having a specific volume resistivity of about 100%.

The silicon carbide thin plates and ceramic thin plates that mainly constitute the substrate of the present invention are l, Si, P, B, and Go.

Ae, Sb, Bi, V, Zn, cd, Pb, Na, K
.

They are firmly bonded by a bonding layer containing at least one oxide selected from Li, Be, Oa, Mg, Ba, Sr, or Zr as a main component.

In the present invention, the bonding layer is an oxide film layer and an AI.

Si, P, B, Go, As,
Sb, Bi, V, Zn,
Od.

Pb, Na, Li, Be, Oa, Mg, Ba, Sr
The oxide film layer is formed on the surface of the silicon carbide thin plate, and the weld layer is composed of the oxide film 1@ Preferably, it is formed by welding ceramic thin plates. The reason is that the oxide film layer is formed by oxidizing the surface of the silicon carbide thin plate, and is extremely firmly bonded to the silicon carbide thin plate by an intricate transition layer. Furthermore, the wettability with the oxide constituting the welding layer is extremely good, and the oxide film layer and the welding layer form a eutectic layer and are integrated, which improves the bondability between the silicon carbide thin plate and the ceramic thin plate. This is because it can significantly improve the quality.

In the present invention, the thermal expansion coefficient of the bonding layer is 2.9×/
θ-6 to 11. Advantageously, it is within the range qX/θ-6/°C. The reason for this is that if the coefficient of thermal expansion is not within the above range, the difference in thermal expansion between the silicon carbide thin plate and the bonding layer will be large, and the bonding layer will be easily destroyed by thermal stress due to temperature cycles or thermal shock. This is because the bondability between the thin plate and the ceramic thin plate is poor.

In the present invention, it is preferable that the softening point of the bonding layer is 00° C. or higher. The reason for this is that the working temperature of the Au-Si eutectic alloy, which has excellent heat dissipation, heat resistance, and ohmic contact properties and is commonly used in the die bonding process where chips are placed and fixed on a substrate, is 1Io.
The working temperature of the low melting point glass method, which is widely used in the hermetic sealing process of substrates and has excellent electrical insulation and wettability for metals, glass, ceramics, etc., is around 1IQO-! Since it is r000G, if the softening point of the bonding layer is 700° C. or higher, die bonding of chips or airtight sealing of the substrate can be performed without deteriorating the bonding properties between the silicon carbide thin plate and the ceramic thin plate. This is because it is possible.

In the present invention, the film thickness i1 of the oxide film layer; /);
/)/~B[mu]m is advantageous. Sobi) I11! The reason is that if the film thickness is less than 0.7 μm, not only will the formation of the transfer layer be insufficient, but also Air III: 111il! Since the formation of a eutectic layer between the chemical coating layer and the welding layer is also insufficient, the bondability between the silicon carbide thin plate and the bonding layer cannot be significantly improved.
On the other hand, an oxide layer thicker than 25 .mu.m takes a very long time to form and is not efficient, and optimal results are obtained within the range of 0.7 to 708 m.

In the present invention, when the oxide film layer is required to be relatively thick and dense, it is possible to contain aluminum oxide to prevent cristobalite formation when the oxide film layer is formed. Advantageously, the Al of aluminum oxide and silicon dioxide contained in the oxide layer
, 03/5102 molar ratio within the range of θ, θ, 29 to /, IF.

In the present invention, the thickness of the bonding layer consisting of the oxide film layer and the welding layer is preferably within the range of /~SOOμm. The reason for this is that if the thickness of the bonding layer is less than /l1m, sufficient bonding strength between the silicon carbide thin plate and the ceramic thin plate cannot be obtained, whereas if it is thicker than 5θOμm, the bonding layer and the silicon carbide thin plate will not be strong enough. This is because the influence due to the difference in coefficient of thermal expansion between the bonding layer and the ceramic thin plate tends to become noticeable, and the ceramic thin plate and the silicon carbide thin plate tend to separate. 200μ
The most favorable results are obtained within the range of m.

In the present invention, it is important that the ceramic thin plate is a ceramic having excellent electrical insulation and a low dielectric constant, such as alumina or mullite.

Preferably, it is at least one selected from cordierite, zirconia, steatite, spinel, forsterite, magnesia, lithia, titania, sialon, silicon nitride, or boron nitride/persimmon-based ceramics. , especially mullite and sillimanite.

Cordierite, Sialon, silicon nitride, etc. have a coefficient of thermal expansion that is relatively close to that of silicon carbide, so the thermal stress caused by temperature cycles or thermal shock is small, and they have excellent bonding properties with thin silicon carbide tubes. More suitable.

In the present invention, the thickness of the ceramic thin plate is o,
os is preferably 1 or more. The reason for this is that the thinner the ceramic thin plate is, the better it is to make electronic components smaller and lighter, and to improve heat dissipation characteristics. 1) When the applied voltage is high; the gas insulation property decreases and the capacitance increases.

This is because the functionality as a substrate deteriorates.

In the present invention, it is preferable that the ceramic thin plate has a chip mounting opening so that the chip can be mounted on the substrate. The reason for this is that when a ceramic thin plate with a chip mounting opening is bonded to the surface of a silicon carbide thin plate, the chip is bonded directly to the surface of the silicon carbide thin plate without using the ceramic thin plate. The heat generated in the chip is immediately transferred to the silicon carbide thin plate, which exhibits excellent heat dissipation properties.Also, since the thermal expansion coefficients of the silicon carbide thin plate and the chip are almost the same, thermal stress due to temperature cycles or thermal shock is almost never generated. This is because the chip has the advantage of being able to obtain extremely reliable bonding without peeling or damage.

In the present invention, the thickness of the silicon carbide thin plate is 0, /~
Advantageously, it is within the 3θ range. The reason is,
The thickness of the silicon carbide thin plate is preferably as thin as possible in order to promote miniaturization of electronic components and improve heat dissipation. If it is thinner than /mu, the strength of the silicon carbide thin plate itself will be weak and the handling will be poor;
This is because if it is thicker than 1, it is difficult to miniaturize the electronic components of the scale, and the cost required for the board increases, making it uneconomical.

Next, a method for manufacturing a silicon carbide substrate of the present invention will be explained.

According to the present invention, (a) means for heating a silicon carbide thin plate in an oxidizing atmosphere; (b) a means for heating a silicon carbide thin plate in an oxidizing atmosphere;
, Si, P, B, Ge, As, Sb, Bi, ,V.

Zn, Cd, Pb, Na, K, L
i, Be, (:a, Mg.

Means for heating the silicon carbide thin plate in an oxidizing atmosphere after applying a composition containing an element selected from Ba, Sr, or Zr or a compound thereof as a full-size component; An oxide film layer is formed on the surface of a silicon carbide thin plate by any of the methods described in (1)), and then Al, Si is applied on at least either the oxide film layer or the ceramic thin plate.

P, B, Ge, As, Sb,
Bi, V, Zn, Od.

P'b, Na, K,, Li, Be, Oa,
After applying a bonding agent composition containing at least seven elements selected from Mg, Ba, Sr, or Zr, or compounds thereof, the silicon carbide thin plate and the ceramic thin plate are stacked and heated at an angle of 0 to 7200°. By heating within the temperature range of C, Al, Si, P, B, Ge, and helium are formed between the silicon carbide thin plate and the ceramic thin plate.

Sb, Bi, V, Zn, O! 4. Pb,
Na, K, Li.

A silicon carbide material for electronic circuits that has excellent electrical insulation properties by forming and bonding a welding layer mainly composed of at least two oxides selected from Be, Ca, Mg, Ba, Sr, or Zr. A substrate is manufactured.

According to the present invention, it is necessary to heat the silicon carbide thin plate in an oxidizing atmosphere to form an oxide film layer. The reason for this is that by heating the silicon carbide thin plate in an oxidizing atmosphere, an oxide film layer with an intricate transition layer is formed on the surface of the silicon carbide thin plate, which improves wettability with the oxide constituting the weld layer. This is because the oxide layer and the welding layer can be integrated by the eutectic layer, resulting in a bonding layer that is extremely uniform and has excellent adhesion.

The mechanism by which the adhesion between the silicon carbide thin plate and the bonding layer is significantly improved by heating the silicon carbide thin plate in an oxidizing atmosphere is that foreign matter adhering to the surface of the silicon carbide thin plate, for example, free By removing impurities such as carbon or by oxidizing the surface of the silicon carbide thin plate, it becomes microscopically roughened, and the bonding area with the bonding layer can be significantly increased. This is presumably due to the fact that the thin plate and the bonding layer are bonded by an intricate transition layer.

According to the present invention, as a means for forming an oxide film layer on the surface of a silicon carbide thin plate, either of the means (a) or (b) described above can be advantageously applied, but in particular, a uniform and extremely dense oxide layer can be applied. If a coating layer is required, it is necessary to use the method (b). The mechanism by which a uniform and extremely dense oxide film layer can be formed by means of (b) is that the composition is applied to the surface of a silicon carbide thin plate and then heated in an oxidizing atmosphere. This is thought to be due to the fact that the composition can be present in an oxide state to completely oxidize the surface of the silicon carbide thin plate, and can prevent the formation of cristobalite of 5102 produced by oxidation of the silicon carbide thin plate. . Note that if a more uniform and dense oxide film layer is required, step S10. It is effective to eutectic aluminum oxide, which has a remarkable effect of preventing the formation of cristobalite, and is capable of supplying aluminum in the form of an oxide in the oxidizing atmosphere when the oxide film layer is formed. A composition containing at least 7 of the following is converted into Al, 03 and θ, ooti ~, 2.9
It is advantageous to apply at a rate of my/cnL2. Said A! Alternatively, various substances can be used as the compound, but among them, alumina sol is the most suitable because it can supply extremely fine and highly reactive aluminum oxide.

According to the present invention, the heating temperature in the oxidizing atmosphere is preferably within the range of 7SO to /6Sθ°C, and it is advantageous to heat to a temperature within the range for at least 70 minutes. The reason is that when the heating temperature is lower than qso°C, the oxidation rate of the silicon carbide thin plate is slow and it is difficult to efficiently generate the oxide film j@;
If the oxidation rate is higher, the oxidation rate is extremely high and it is not only difficult to control the thickness of the oxide film layer to the desired thickness, but also the CO gas generated during oxidation of silicon carbide may damage the oxide film layer and the silicon carbide thin plate. This is because air bubbles are generated between the two, which deteriorates the adhesion. It is also advantageous to heat to a temperature within this range for at least 70 minutes, since it is difficult to obtain a sufficiently reliable oxide layer if the heating time is shorter than 70 minutes. Note that the best results can be obtained when the heating temperature is in the range of qoo to /'430°C.

According to the present invention, Al, Si, and P are formed on at least one of the oxide layer and the ceramic thin plate.

B, Ge, As, Sb, Bi, V, Zn,
Cd,, Pb.

Na, K, Id, Be, Oa, Mp,
After applying a bonding agent composition containing at least seven elements selected from Ba, Br, or Zr or their compounds, the silicon carbide thin plate and the ceramic thin plate are stacked and heated at a temperature of 200°C. By heating within this range, 1, Si, P, B, Ge, As, and Sb are formed between the silicon carbide thin plate and the ceramic thin plate.

Bi, V, Zn, O(1, Pb, Na, Ll,:
se.

By forming and bonding a welding layer mainly composed of at least two oxides selected from Oa, Mg, Ba, Sr, or Zr, a silicon carbide substrate for electronic circuits with excellent electrical insulation properties is produced. can be manufactured.

The reason why the heating temperature when forming the welding layer is set within the range of 25θ to /koθθ°C is that if the temperature is lower than 50°C, the oxide film layer and the welding layer are mutually eutectic and bonded uniformly. On the other hand, if the temperature is higher than /100°C, the viscosity of the oxide produced from the bonding agent composition decreases significantly, making it difficult to form a uniform bonding layer. Note that the best results can be obtained when the heating temperature is within the range of 300 to //θO°C.

According to the present invention, the ceramic thin plate mainly contains at least seven selected from alumina, mullite, sillimanite, zirconia, steatite, spinel, forsterite, magnesia, ricia, titania, sialon, silicon nitride, and boron nitride. However, when using ceramic thin plates containing silicon nitride or boron nitride as a main component, it is recommended to oxidize their surfaces in advance to form an oxide film layer before use. is advantageous.

According to the present invention, it is preferable to bond a ceramic thin plate having a chip-placing opening to the surface of the silicon carbide thin plate so that the chip can be placed on the substrate. Ceramic thin plates having such properties can be produced, for example, by blanking a green sheet or other so-called raw processing, followed by firing, by molding with a press mold that can form a green body having an opening for placing a chip, and then firing. It can be manufactured by processing a thin plate obtained by ultrasonic processing or the like.

In addition, according to the present invention, for the purpose of further increasing the density, it is also possible to have a structure in which more than one ceramic thin plate is further laminated on each of the ceramic thin plates with a bonding layer interposed therebetween.

Next, the present invention will be explained with reference to examples.

Example 1 Silicon carbide thin plate contains boron / 0 weight ratio and free carbon 2
．． 3. Contains 0% by weight. A pressureless sintered body of silicon carbide having a density of /f/cw', 30X30X, z
A thin plate of 100 g was polished in advance, and the surface was finally finished with a +/200 grindstone, and then boiled in acetone to degrease it.

The silicon carbide thin plate was immersed in an aqueous solution in which 7.62% of calcium chloride was dissolved in an alumina sol/wt% aqueous solution of 100%, and then placed in a dryer and dried at 100C for 7 hours. On the surface of the silicon carbide thin plate, alumina sol of about 0.0'l mf/CrIL2 in terms of Al2O3 and calcium chloride of about θ, It ml/ryn2 in terms of CaO were present.

Next, the inner diameter of the silicon carbide thin plate is ? It was charged into an O-ryu tube furnace and subjected to oxidation treatment. In the oxidation treatment, oxygen gas was charged into the tube furnace at a rate of 11,700 tt/wR.
This was done by heating at ℃ for 7 hours.

The obtained oxide film layer was transparent and glassy, had a thickness of about θ, q μm, and had a smooth surface texture of 1.

Note that the Al2O3/5102 molar ratio of this oxide film layer was 0.30.

Furthermore, 5102 and At, 03. !
Ceramic thin plates are bonded by a screen printing method using a bonding agent composition mainly composed of components 4 and 11 mixed with 7pbo in a molar ratio of 72:10:/3.
r11 and dried at 720°C for 30 minutes.

A thin mullite plate of 30×30×/H and having an opening for chip mounting as shown in FIG. 2 was superimposed on the silicon carbide thin plate, and the plate was charged into a firing furnace and heated at 1 to 10°C/mrn. After heating and holding at the maximum gsθ0C for 30 minutes, it was slowly cooled at room temperature to produce silicon carbide with a collapsed f* layer structure as shown in Figure 7. E. Obtained a board.

The thickness of the bonding layer of the obtained silicon carbide substrate is approximately 70 μm.
Almost no defects such as pin poles were observed, and the silicon carbide thin plate and the mullite thin plate were in extremely strong contact with each other.

The insulation resistance at the point where the thin mullite plate of the silicon carbide substrate is attached is 1014Ω when the applied voltage is /θ0■
As described above, the withstand voltage was /3 KV and the capacitance was 0.9 PF. In addition, the above-mentioned absolute resistance is JIS-0-5O/2
7, 3 with withstand voltage J-C-, 2/10 go,
? (, 27), and the capacitance was measured by printing electrodes for measurement on a thin mullite plate using silver paste, as shown in Figure 3.
The capacitance between both electrodes was measured at a frequency of /MHz.

Example 2 A silicon carbide thin plate that had been surface-finished and deoxidized in the same manner as in Example 1 was charged into the tubular furnace used in Example 1, and oxidized in the same manner as in Example 1. . By the above treatment, the surface of the silicon carbide thin plate has a thickness of about θ, 05 μm.
An oxide film layer consisting of 102 films was obtained.

Next, the mullite thin plate was joined to the silicon carbide thin plate in the same manner as in Example 1.

The properties of the obtained silicon carbide substrate were measured in the same manner as in Example 1 and are shown in Table 1.

Example 3 A silicon carbide substrate base was obtained in substantially the same manner as in Example 1, except that the ceramic thin plates shown in Table 1 were used and the thickness of the bonding layer was changed as shown in Table 7.

The properties of the obtained silicon carbide substrate were measured in the same manner as in Example 1 and are shown in Table 1.

Example 4 S10. and B2O3 and pbo and Δl, 03
And is the molar ratio! ;2:4 A bonding agent composition containing the composition blended in A as a main component was applied by a screen printing method and dried at 100°C for an hour.

A sillimanite thin plate was stacked on the silicon carbide thin plate coated with the bonding agent composition, and a silicon carbide substrate was obtained in the same manner as in Example]-, except that the heating temperature was raised to 900°C.

The properties of the obtained silicon carbide substrate were measured in the same manner as in Example 1 and are shown in Table 1.

Example 5 Same as Example 4, except that the binder composition was S10.
The molar ratio of B2O3 and Al2O3 is A? : 100
A silicon carbide substrate was obtained by using a bonding agent composition containing the composition blended in / as a main component, an alumina thin plate as the ceramic thin plate, and increasing the heating temperature to 7000°C.

The properties of the obtained silicon carbide substrate were measured in the same manner as in Example 1 and are shown in Table 1.

Example 6 The same method as in Example 1 was used, except that an 8102 film with a thickness of 0.0 S μm was formed on the surface of a thin ceramic plate.
810. of the silicon nitride thin plate is used.
S10 on the coating. After applying a bonding agent composition containing B2O3, Al2O3, and 20 in a molar ratio of 3.3://:3:;l, a silicon carbide thin plate and a silicon nitride thin plate were stacked. A silicon carbide substrate was obtained in the same manner as above, but the heating temperature was increased to 900°C.

The properties of the obtained silicon carbide substrate were measured in the same manner as in Example 1 and are shown in Table 1.

Example 7 The method was almost the same as in Example 1, but an oxide film layer was formed by coating a silicon carbide thin plate with an alumina sol/gravitational aqueous solution containing the substances shown in the second coating. , a silicon carbide substrate was obtained.

The values of the actual amount of oxide present on the surface of the silicon carbide thin plate after drying and the thickness of the obtained oxide film layer are shown in the second column.

/' (3/) The electrical properties of the silicon carbide substrate obtained are that the insulation resistance value is 1013Ω or more, and the withstand voltage is 72 KV 1g or more.

The capacitance was /, /)F or less, and the bondability between the silicon carbide thin plate and the mullite thin plate was also extremely good.

Example date Almost the same as Example 1, except that the ceramic thin plates were cordierite, zirconia, steatite, spinel, forsterite, and magnesia.

A silicon carbide substrate was obtained using Lisia, Titania, and Sialon.

The electrical properties of the obtained silicon carbide substrates include an insulation resistance value of 7013Ω or more and a withstand voltage of /2KV or more.

The capacitance was 2.3 pFF or less, and the bondability between the silicon carbide thin plate and the ceramic thin plate was also good.

As described above, according to the present invention, a silicon carbide thin plate having almost the same coefficient of thermal expansion as a silicon chip, capable of directly bonding the silicon chip, and having excellent heat dissipation properties can be used as an integrated circuit substrate or an IC. It can be extremely advantageously applied as a packaging material.

In addition, it is possible to supply a silicon carbide substrate that has extremely low capacitance and can exhibit extremely high circuit functions, which has an extremely significant effect on industry.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the laminated structure of a silicon carbide substrate manufactured in Example 1 of the present invention, and FIG. 2 is a schematic diagram showing the shape of a ceramic thin plate used in Example 1 of the present invention. FIG. 3 is a diagram showing the shape of an electrode made of silver paste on a thin ceramic plate for measuring capacitance in Example 1 of the present invention. l...Silicon carbide thin plate, C...oxide film layer 13...
・Welding layer, D...ceramic thin plate, S...Silver-
Strike. Patent applicant Ibigawa Electric Industry Co., Ltd.

Claims (1)

[Claims] 1. A thin ceramic plate having a specific volume resistivity of 106 Ωα or more is AI, Bj, P, 1, Ge. As, 8b, Bi, V, Zn, cd, Pb, Na. K, Li, Be, C! a, Mg, B
a. A silicon carbide substrate for an electronic circuit, which is bonded to the surface of a silicon carbide thin plate by a bonding layer containing at least seven oxides selected from Elr or Zr as a main component. 2, @ bonded gold layer is an oxide layer and Al, 611-
, P, B. Go, As, Sb, Bi, V, Z
n, Cd, Pb. It consists of a welding layer mainly composed of Na, and at least two oxides selected from Li, Be, Oa, Mg, Ba, sr, or Zr, and the oxide film layer is formed on the surface of the silicon carbide thin plate. 2. The substrate according to claim 1, wherein the welding layer is formed by welding an oxide film layer and a ceramic thin plate. 3. The substrate according to claim 1 or 2, wherein the thickness of the bonding layer is within the range of /~SOOμm. 4 The ceramic thin plate is alumina, mullite, sillimanite, cordierite, zirconia, steatite, spinel, forsterite, magnesia, lithia,
The substrate according to any one of claims 1 to 3, which is a ceramic whose main component is at least one selected from titania, sialon, silicon nitride, and boron nitride. 5. The thickness of the ceramic thin plate is at least θ, o
The substrate according to any one of claims 1 to 4, which is r. 6. The substrate according to any one of claims 1 to 5, wherein a ceramic thin plate having a chip placement opening is bonded to the surface of a silicon carbide thin plate so that a chip can be placed on the substrate. . 7. (a) Means for heating a silicon carbide thin plate in an oxidizing atmosphere (b) A, i! on the surface of a silicon carbide thin plate. , Si,
P. B, Go, As, Sb, Bi, V, Zn,
Cd. P'b, Na, K, Li, Be, C! a,
Means for heating the silicon carbide thin plate in an oxidizing atmosphere after coating a composition containing at least seven elements selected from Mg, BatSr, or Zr or compounds thereof as a main component (a). An oxide film layer is formed on the surface of the silicon carbide thin plate by any of the methods described in b), and then AI, Si, P, and B are applied on at least one of the oxide film layer and the ceramic thin plate. Ge, As, Sb, Bi, V, Zn, C! d, Pb. NaSoLi, Be, Oa, Mg, Ba, Sr
Alternatively, after applying a bonding agent composition containing at least seven of the elements selected from Zr or their compounds, a silicon carbide thin plate and a ceramic thin plate are stacked and heated within a temperature range of UT θ~/Y θθ℃. By heating, Al, 8 is formed between the silicon carbide thin plate and the ceramic thin plate.
1. . P, B, Ge, As, Sb, Bi, V, Zn, Cd. Pb, Na, Li, Be, Ca, Mg, Ba. A method for manufacturing a silicon carbide substrate for an electronic circuit having excellent electrical insulation properties, which comprises forming and bonding a welding layer mainly composed of at least two oxides selected from Sr and Zr. a The ceramic thin plate is a ceramic whose main component is at least seven selected from alumina, mullite, sillimanite, zirconia, steatite, spinel, forsterite, magnesia, lithia, titania, sialon, silicon nitride, and boron nitride. A manufacturing method according to claim 7. 9. The thickness of the ceramic thin plate is at least O.o.
The manufacturing method according to claim 7 or 8, which is smrtt. 10. The imaging method according to any one of claims 7 to 9, wherein the heating temperature in the means (a) and (b) is within a temperature range of 7Sθ to 0°C. LL After applying the bonding agent composition, a silicon carbide thin plate and a ceramic thin plate are stacked and heated within a temperature range of 300 to 100°C, the manufacturing method according to any one of claims 7 to 10. . 12. The manufacturing method according to any one of claims 7 to 11, wherein a ceramic thin plate having a chip placement opening is bonded to the surface of the silicon carbide thin plate so that the chip is placed on the substrate.