JPH05327146A - Ceramic substrate for hybrid ic and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To provide a ceramic substrate for hybrid IC comprising titanium oxide or aluminum oxide not covered with glass and manufacturing method thereof. CONSTITUTION:This ceramic substrate for hybrid IC comprising titanium oxide or aluminum oxide having not exceeding 100each/mm<2> of pores in diameter exceeding 3mum but no pores at all in diameter exceeding 30mum on the surface thereof wherein high purity titanium or aluminum oxide particles are baked in atmospheric, inert or reducing atmosphere and then HIP processed (the former and the latter respectively at 1100 deg.C-1300 deg.C and 1200 deg.C-1400 deg.C) further to be heat-treated later for manufacture. Accordingly, due to the least number of pores in diameter exceeding 3mum and no pores in diameter exceeding 30mum at all on the surface, the wiring formed on the substrate can be made finer and high-densified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid IC ceramic substrate and a method of manufacturing the same, and more particularly to a hybrid IC ceramic substrate for forming a thin film circuit and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, various ceramic substrates have been used as insulating substrates for hybrid ICs. For example, in the case of a ceramic substrate made of a titanium oxide substrate or an aluminum oxide substrate, a pore having a diameter of 3 μm or more is formed on the surface thereof. There are a large number of these, and they were unsuitable as insulating substrates for hybrid ICs. Therefore, the pores on the substrate surface are currently
In order to eliminate the above, glass is coated on a ceramic substrate and used as a glass layer-covered ceramic substrate.

[0003]

By the way, with the high integration of ICs, high density wiring of the substrate on which the IC is mounted has become an important issue today, and in order to achieve high density wiring, fine wiring is required. Technology is being actively researched. And
With the progress of finer wiring, the existence of pores and the number thereof, especially large pores having a diameter of 30 μm or more, existing on the surface of a substrate forming the wiring has become a problem.

In order to solve the above problems, the glass layer-covered ceramic substrate is used as described above.
In this substrate, not only the complicated step of coating the glass layer is required, but also the glass layer and the ceramic substrate are separated from each other when the substrate is manufactured or the wiring is formed, or depending on the wiring forming means, the glass layer-covered substrate. However, it has the drawback that it cannot be used. Therefore, as an insulating substrate for a hybrid IC, the emergence of a single-component ceramic substrate that does not coat glass or the like and has no pores on the surface is strongly desired.

It is an object of the present invention to provide a hybrid IC substrate made of ceramic and a method for manufacturing the same, which meets the above-mentioned demand. More specifically, the present invention has very few pores with a diameter of 3 μm or more on the substrate surface,
An object is to provide a ceramic substrate for a hybrid IC, which has no pores larger than a diameter, and a method for manufacturing the same.
An object of the present invention is to provide a ceramic substrate for a hybrid IC, which enables fine wiring to be formed on the substrate and enables high density wiring.

[0006]

The present invention provides (1)
A titanium oxide substrate or an aluminum oxide substrate which has not been subjected to a coating treatment such as glass coating on the surface,
Featuring a ceramic substrate for hybrid IC, which has extremely few pores with a diameter of 3 μm or more on the surface of 100 μm / mm ² or less, and has no pores with a diameter of 30 μm or more.
Further, (2) the method for producing the substrate is characterized in that titanium oxide or aluminum oxide powder having a specific average particle size and a specific purity is used as a raw material and is fired under specific firing conditions.

That is, (1) the ceramic substrate for hybrid IC of the present invention comprises a "titanium oxide substrate or an aluminum oxide substrate whose surface is not coated with glass coating or the like, and having a diameter of 3 μm existing on the substrate surface. Hybrid I characterized in that the number of pores is 100 or less per 1 mm ² , and the titanium oxide substrate or aluminum oxide substrate does not have pores with a diameter of 30 μm or more.
Ceramic substrate for C. Is the gist.

(2) As a method of manufacturing the above substrate, the method of manufacturing a titanium oxide substrate is "(A) average particle size 1 μm".
After molding titanium oxide powder with a purity of 99% or more,
Baking in an air atmosphere or an inert atmosphere at 00 to 1300 ° C., (B) 500 kg / cm ^{2 of the} sintered body obtained in (A) above.
HIP treatment under the above pressure and further heat treatment at 700 to 900 ° C, (C) firing in a reducing atmosphere instead of the air atmosphere or the inert atmosphere of (A) above, and further heating at 700 to 900 ° C Treatment, (D) firing in a reducing atmosphere instead of the air atmosphere or the inert atmosphere in (A) above, 500 kg / c
A method for producing a ceramic substrate for a hybrid IC comprising a titanium oxide substrate, which comprises HIPing under a pressure of m ² or more and further heat-treating at 700 to 900 ° C. ], And the manufacturing method of the aluminum oxide substrate is
“(A) Forming aluminum oxide powder with an average particle size of 1 μm or less and a purity of 99% or more, and then firing at 1200 to 1400 ° C. in the atmosphere, an inert atmosphere or a reducing atmosphere, (B) obtained in (A) above HIP the sintered body under a pressure of 500 kg / cm ² or more.
A method of manufacturing a ceramic substrate for a hybrid IC, which is made of an aluminum oxide substrate. "
Is the gist.

The present invention will be described in detail below. As a result of diligent research conducted by the present inventors on a method for producing a ceramic substrate having no pores on the surface, the above method (2) results in The present invention has been completed by finding that the "titanium oxide or aluminum oxide sintered body having extremely few pores on the surface and having no pores having a diameter of 30 µm or more" described in (1) can be obtained. That is, the present inventors have found that, according to the production method of the above (2), the pores can be retained in the crystal grains as extremely fine pores without the pores accumulating at the grain boundaries and becoming apparent. Above (1) and
The present invention of (2) has been completed.

In the present invention, as the titanium oxide powder or aluminum oxide powder used as a raw material, it is preferable to use one having a high purity of 99% or more. If it is less than 99%, it is difficult to obtain the "target substrate having very few pores having a diameter of 3 µm or more and no pores having a diameter of 30 µm or more" on the surface of the substrate, which is not preferable (Comparative Example 5 described later). , 6, 13, 14). The raw material powder preferably has an average particle diameter of 1 μm or less. 1
When it exceeds μm, it is difficult to obtain the above-mentioned substrate which is the same as the object of the present invention, which is not preferable (Comparative Examples 7, 8, 15,
16).

The raw material powder used in the present invention will be described in more detail. When the purity is less than 99%, the average particle size is
If it is coarser than 1 μm, as will be described later, the property of low temperature easy sintering is lost and the sintered density cannot be sufficiently increased. On the other hand, when sintered at a high temperature to increase the sintered density, grain growth occurs and the pores become coarse (Comparative Examples 1 to 16 below).
reference).

Therefore, in the present invention, the titanium oxide powder or aluminum oxide powder used as a raw material preferably has a high purity of 99% or more and an average particle size of 1 μm or less, and a high purity of 99.8% or more. 0.5 μm
It is more preferable to use titanium oxide powder or aluminum oxide powder having the following average particle diameter.

In the present invention, the raw material fine powder is molded into a ceramic green sheet by a doctor blade method, an extrusion method or the like. The obtained green sheet is debindered if necessary, and then fired while controlling firing conditions. This firing temperature condition is different between the titanium oxide substrate and the aluminum oxide substrate, and is 11 for the titanium oxide substrate.
00 ~ 1300 ℃, 1200 ~ 1400 for aluminum oxide substrate
Bake at ° C.

If the firing temperature is lower than 1100 ° C. (in the case of titanium oxide substrate) or lower than 1200 ° C. (in the case of aluminum oxide substrate), the sintering itself is difficult to proceed and it is difficult to obtain the respective sintered bodies. At a firing temperature exceeding 1,300 ° C (in the case of titanium oxide substrate) or 1400 ° C (in the case of aluminum oxide substrate), the number of pores having a diameter of 3 µm or more, which is the object of the present invention, is extremely small,
It is difficult to obtain a substrate that has no pores larger than the diameter.
Not preferable.

To further explain the above-mentioned firing temperature, in the present invention, the firing temperature usually used for titania ceramics and alumina ceramics (in the former case, about 1340 ° C.,
In the latter case, the temperature is lower than 1500-1600 ℃)
℃ "and" 1200 ~ 1400 ℃ "to burn, 1300
At temperatures exceeding ℃ (for titanium oxide substrate) and 1400 ℃ (for aluminum oxide substrate), grain growth (crystal growth) is remarkable, and migration of pores to the grain boundary phase and coarsening of pores accompanying grain growth occur. It is not preferable because it occurs. In the present invention, in order to facilitate such low-temperature sintering (in order to exhibit low-temperature easy-sinterability), the above-mentioned 99
% Titanium oxide powder or aluminum oxide powder having a high purity of not less than 1% and an average particle diameter of not more than 1 μm is used.

In the present invention, in order to further reduce surface pores, the titanium oxide or aluminum oxide sintered body obtained under the above firing conditions is further subjected to HIP treatment (for example, treatment in a HIP furnace having a carbon heater). ) Can be applied. This HIP treatment is preferably carried out at a temperature somewhat lower than the firing temperature from the viewpoint that coarsening of pores due to grain growth does not occur, and the pressure is preferably 500 kg / cm ² or more, more preferably 15
00 kg / cm ² or more. The HIP processing conditions are
In the case of titanium oxide and aluminum oxide, it is different. In the former, specifically, it is 1500 k at a temperature of 800 to 1100 ° C.
The pressure is preferably g / cm ² , and the latter is 1000
It is preferable to carry out at a pressure of 1800 kg / cm ^{2 at} less than -1400 ° C.

As the atmosphere during the firing, in either case of titanium oxide or aluminum oxide, the atmosphere, an inert atmosphere (for example, argon atmosphere) or a reducing atmosphere (for example, nitrogen atmosphere by using carbon heater) is used. It can be baked. When firing in a reducing atmosphere among the above atmospheres, unlike the aluminum oxide substrate, the titanium oxide substrate is reduced during the firing and becomes a semiconductor, so that it cannot be used as it is as an insulating substrate for hybrid IC.

Therefore, in order to make this semiconductorized surface an insulator, it is necessary to further heat-treat the titanium oxide sintered body obtained by firing in a reducing atmosphere at 700 to 900 ° C. in the atmosphere. In the case of a titanium oxide substrate, the above-mentioned HI
Even when the P treatment is performed, semiconductor formation is recognized, and thus, in this case as well, it is necessary to perform the heat treatment. If necessary, the surface of the titanium oxide substrate or aluminum oxide substrate thus obtained may be subjected to surface grinding or lapping.

[0019]

EXAMPLES Examples of the present invention will be given below together with comparative examples.
The present invention will be described in more detail. (Examples 1 to 4) Polyvinyl butyral and ethyl alcohol were added to titanium oxide powder having an average particle size of 0.25 μm and a purity of 99.8% and mixed to form a slurry, and then a green sheet was prepared by a doctor blade method.

After this green sheet was debindered, it was fired under atmospheric pressure sintering conditions (temperature 1200 ° C., air or nitrogen atmosphere) shown in Table 1, and in Examples 2 and 4, Table 1 was used.
HI having carbon heater in an argon atmosphere under the HIP treatment conditions (1000 ° C., pressure of 1500 kg / cm ² ) shown in FIG.
HIP treatment was performed in a P furnace. Next, in Examples 2 to 4 except for Example 1, heat treatment was performed at 700 to 900 ° C in the air atmosphere.

When the pores existing on the surface of each of the obtained titanium oxide substrates were observed, there were no pores having a diameter of 30 μm or more. Further, the number of pores having a diameter of 3 μm or more was measured, and the results are shown in Table 1. The diameter and the number of pores on the substrate surface were observed with a scanning electron microscope,
It was measured using a photograph of the obtained image.

Example 5 Average particle size 0.7 μm, purity 99.2
% Of titanium oxide powder, polyvinyl butyral and ethyl alcohol were added and mixed to form a slurry, and then a green sheet was prepared by the doctor blade method.

After this green sheet was debindered, it was fired under atmospheric pressure sintering conditions shown in Table 1 (temperature 1200 ° C., atmospheric atmosphere), and further subjected to HIP treatment in an argon atmosphere under the HIP treatment conditions shown in Table 1 ( The same HIP treatment as in Examples 2 and 4) was performed, and then heat treatment was performed at 700 to 900 ° C. in the atmosphere. When the pores existing on the surface of the obtained titanium oxide substrate were observed, there were no pores having a diameter of 30 μm or more. Further, the number of pores was measured as in Examples 1 to 4, and the results are shown in Table 1.

(Examples 6 to 9) Average particle size 0.25 μm, purity
Polyvinyl butyral and ethyl alcohol were added to 99.9% aluminum oxide powder and mixed to form a slurry, and then a green sheet was prepared by the doctor blade method.

After debinding the green sheet, it was fired under atmospheric pressure sintering conditions (temperature 1400 ° C., air or nitrogen atmosphere) shown in Table 1, and in Examples 7 and 9, Table 1 was used.
The HIP treatment was performed in an argon atmosphere under the HIP treatment conditions shown in (1350 ° C., pressure of 1800 kg / cm ² ). When the pores existing on the surface of each of the obtained aluminum oxide substrates were observed, there were no pores having a diameter of 30 μm or more. Further, the number of pores was measured as in Examples 1 to 4, and the results are shown in Table 1.

Example 10 Average particle size 0.6 μm, purity 99.
After adding polyvinyl butyral and ethyl alcohol to 2% aluminum oxide powder and mixing to make a slurry,
A green sheet was produced by the doctor blade method.
After debinding the green sheet, it is fired under atmospheric pressure sintering conditions shown in Table 1 (temperature 1400 ° C., atmospheric atmosphere), and HIP processing conditions shown in Table 1 (1350 ° C., 1800 k).
HIP treatment was performed in an argon atmosphere at a pressure of g / cm ² . When the pores existing on the surface of the obtained aluminum oxide substrate were observed, there were no pores having a diameter of 30 μm or more. Further, the number of pores was measured as in Examples 1 to 4, and the results are shown in Table 1.

[0027]

[Table 1]

(Comparative Examples 1 to 8) Using the titanium oxide powders having the purities and the average particle diameters shown in Table 2, a green sheet was prepared in the same manner as in Examples 1 to 4 and debindered. After that, firing was performed under the normal pressure sintering conditions and the HIP treatment conditions shown in Table 2, and the same heat treatment as in the above-described example was performed except for Comparative Examples 1, 5, and 7. The number of pores of each of the obtained titanium oxide substrates was measured in the same manner as in Examples 1 to 4, and the results are shown in Table 2.

(Comparative Examples 9 to 16) The aluminum oxide powder having the purity and the average particle size shown in Table 2 was used, and the above-mentioned Examples 6 to 6 were used.
A green sheet was prepared by the same method as in Example 9, debindered, and then fired under the normal pressure sintering conditions and HIP treatment conditions shown in Table 2. For each obtained aluminum oxide substrate,
The number of pores was measured in the same manner as in Examples 1 to 4, and the results are shown in Table 2.
It was shown to.

[0030]

[Table 2]

As is apparent from Table 1 above, the average particle size is 0.
After forming a titanium oxide powder having a particle size of 25 μm and a purity of 99.8% and firing it at 1200 ° C. in the air or nitrogen, in Examples 1 and 3, 3 μm
The number of pores with a diameter of m or more (but none with a diameter of 30 μm or more) is 70
The number of particles / mm ² was obtained, and in Examples 2 and 4 in which the sintered bodies obtained in Examples 1 and 3 were further subjected to HIP treatment, 34 pieces / mm ² and 38 pieces / mm ^{2 were obtained.} I got that. From this, it can be understood that the HIP treatment further reduces the pores having a diameter of 3 μm or more present on the surface of the substrate, and is more suitable as a ceramic substrate for hybrid IC.

Similarly, after molding an aluminum oxide powder having an average particle size of 0.25 μm and a purity of 99.9%, it is exposed to air or nitrogen.
In Examples 6 and 8 fired at 1400 ° C, the number of pores was 85 / m.
m ² , 82 pieces / mm ² were obtained, and this Example
In Examples 7 and 9 in which the sintered bodies obtained in Nos. 6 and 8 were further subjected to HIP treatment, those having 48 pieces / mm ² and 40 pieces / mm ² were obtained. Therefore, similar to the titanium oxide substrate, by further performing HIP treatment on the aluminum oxide substrate, the number of pores having a diameter of 3 μm or more existing on the surface of the substrate is extremely reduced (however, there is no diameter of 30 μm or more), and the hybrid IC It can be understood that the ceramic substrate is more suitable as a ceramic substrate.

Further, titanium oxide powder having an average particle size of 0.7 μm and a purity of 99.2% (a raw material having an average particle size larger than that of Example 2 and having a low purity, both of which are within the scope of the present invention)
Example 5 using the above and an aluminum oxide powder having an average particle size of 0.6 μm and a purity of 99.2% (the average particle size is larger than that of Example 7 and is a low-purity raw material, but both are within the scope of the present invention. In Example 10 in which the raw material) was used, the number of pores was
Though and more than Example 7, both are of the present invention 92 or within 100 intended in / mm ² and 96 / mm ^2, moreover, the pores on 30μm diameter or - obtain what is none Therefore, it can be used as a ceramic substrate for a hybrid IC.

In comparison with Examples 1 to 10 above, as is clear from Table 2, the raw material powders having the average particle size (1 μm or less) and the purity (99% or more) defined in the present invention Even when used, the firing temperature is also outside the range specified in the present invention (1100 to 1300 ° C for titanium oxide powder, 1200 to 1400 ° C for aluminum oxide powder), especially 1600 ° C exceeding the upper limit. In Comparative Examples 1 to 4 and 9 to 12 which were fired in Example 1, even when the HIP treatment was performed, those having at least about 500 pieces / mm ² to about 1000 pieces / mm ² pores were present on the surface, It was not suitable as a ceramic substrate for IC.

Further, as seen in Comparative Examples 5 and 6 and Comparative Examples 13 and 14, the use of raw material powders with a purity of less than 99%,
Further, as seen in Comparative Examples 7 and 8 and Comparative Examples 15 and 16,
If a raw material powder having an average particle size of more than 1 μm is used, it must be fired at a temperature higher than the firing temperature specified in the present invention,
As a result, many pores were present on the surface, which was also unsuitable as a ceramic substrate for hybrid ICs.

As is clear from the comparison between Tables 1 and 2, the present invention uses, as the raw material powder, high-purity titanium oxide fine powder or high-purity aluminum oxide fine powder having an average particle size of 1 μm or less and a purity of 99% or more. Use, in the case of titanium oxide fine powder raw material, 1100 ~ 1300 ℃,
In the case of aluminum oxide fine powder raw material, by firing at 1200 to 1400 ° C.
A ceramic substrate for hybrid ICs made of titanium oxide or aluminum oxide, which has extremely few pores with a diameter of μm or more and no pores with a diameter of 30 μm or more. Furthermore, a substrate with a smaller number of pores by HIP treatment. Understand that you can get.

[0037]

As described in detail above, the present invention comprises, as a hybrid IC ceramic substrate, a titanium oxide substrate or an aluminum oxide substrate whose surface is not coated with glass coating or the like, and has a surface of 3 μm.
There is an effect that it is possible to provide the above-mentioned substrate in which the number of pores having a diameter larger than 100 μm / mm ² is extremely small and there is no pore having a diameter of 30 μm or more. Further, as a method for producing the substrate, by using high-purity titanium oxide or aluminum oxide fine powder as a raw material and firing under specific firing conditions,
There is an effect that pores with a diameter of 30 μm or more can be eliminated. And a hybrid IC according to the present invention
It is possible to provide a ceramic substrate for a hybrid IC, which enables finer wiring formed on the ceramic substrate for use in the circuit and enables higher density wiring.

Claims (7)

[Claims] 1. A titanium oxide substrate or an aluminum oxide substrate which has not been subjected to a coating treatment such as glass coating on the surface, and the number of pores having a diameter of 3 μm or more present on the surface of the substrate is 100 or less per 1 mm ² , and 30 μm A ceramic substrate for a hybrid IC, comprising the titanium oxide substrate or aluminum oxide substrate having no pores having a diameter larger than the diameter. 2. A hybrid comprising a titanium oxide substrate, characterized in that a titanium oxide powder having an average particle size of 1 μm or less and a purity of 99% or more is molded and then fired at 1100 to 1300 ° C. in an air atmosphere or an inert atmosphere. Manufacturing method of ceramic substrate for IC. 3. A titanium oxide powder having an average particle size of 1 μm or less and a purity of 99% or more is molded and then fired at 1100 to 1300 ° C. in an air atmosphere or an inert atmosphere and HIP under a pressure of 500 kg / cm ² or more. A method of manufacturing a ceramic substrate for a hybrid IC, comprising a titanium oxide substrate, which is characterized by subjecting to heat treatment and further heat treatment at 700 to 900 ° C. 4. A titanium oxide powder having an average particle size of 1 μm or less and a purity of 99% or more is molded, fired in a reducing atmosphere at 1100 to 1300 ° C., and further heat treated at 700 to 900 ° C. A method for manufacturing a ceramic substrate for a hybrid IC, which comprises a titanium oxide substrate. 5. A titanium oxide powder having an average particle size of 1 μm or less and a purity of 99% or more is molded, fired in a reducing atmosphere at 1100 to 1300 ° C., HIP-treated under a pressure of 500 kg / cm ² or more, and further A method for manufacturing a ceramic substrate for a hybrid IC, comprising a titanium oxide substrate, characterized by being heat-treated at 700 to 900 ° C. 6. An aluminum oxide substrate characterized by being formed into an aluminum oxide powder having an average particle size of 1 μm or less and a purity of 99% or more and then firing at 1200 to 1400 ° C. in the atmosphere, an inert atmosphere or a reducing atmosphere. Become hybrid I
A method for manufacturing a ceramic substrate for C. 7. An aluminum oxide powder having an average particle size of 1 μm or less and a purity of 99% or more is molded and then fired at 1200 to 1400 ° C. in the atmosphere, an inert atmosphere or a reducing atmosphere to obtain 500 kg.
A method for manufacturing a ceramic substrate for a hybrid IC, which comprises an aluminum oxide substrate, characterized by performing HIP treatment under a pressure of not less than 1 cm ² / cm ² .