JPH0948660A - Insulating porcelain and multilayered wiring substrate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low-cost insulating porcelain capable of being baked at low temperatures by forming and baking a mixture of a specific glass having a low yield point with a filler comprising a specific metallic oxide. SOLUTION: This insulating porcelain is obtained by forming a mixture of 20-50vol.% crystallizable glass having <=8ppm/ deg.C linear thermal expansion coefficient at 40-400 deg.C and 400-600 deg.C yield point without containing Pb with 50-80vol.% filler comprising a metallic oxide having <=8ppm/ deg.C linear thermal expansion coefficient at 40-400 deg.C and then baking the resultant formed mixture. The linear thermal expansion coefficient of the produced porcelain is <=6.5ppm/ deg.C. A conductor consisting essentially of copper is arranged in the interior or the surface of the insulating porcelain to form the multilayered wiring substrate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an insulating porcelain suitably used as a substrate on which a semiconductor element or the like is mounted,
The present invention relates to an inexpensive insulating porcelain fired at a low temperature and a multilayer wiring board using the same.

[0002]

2. Description of the Related Art Conventionally, as a substrate material for mounting semiconductor elements and the like, alumina porcelain or the like has been generally used, and a conductor layer made of a refractory metal such as tungsten is formed on the surface thereof to produce a wiring board. It had been.

Recently, in order to manufacture at low cost, a low temperature firing porcelain has been developed which can be fired at the same time by using a low melting point metal such as gold, silver or copper as a conductor material. There is. As such a low-temperature fired porcelain, a so-called glass-ceramic material has been proposed in which glass powder is used as a liquid phase forming component and a filler component is added to the glass powder and fired. However, the raw material cost of the glass powder used in the glass-ceramic material is high, and the product cost is inevitably high at present.

In order to solve the above problem, for example, Japanese Patent Publication No. 4-75868 proposes a porcelain which is prepared by adding mullite, dumbrite, petalite and forsterite at a predetermined ratio and firing at 1000 ° C. or less. There is. According to this publication, there is an advantage that it can be manufactured at low cost because low temperature firing is possible without using expensive glass at all.

Further, in Japanese Unexamined Patent Publication (Kokai) No. 5-7060, two types of alumina having different particle diameters are mixed at a predetermined ratio, and glass having a low softening point is added to the mixture to obtain an insulating material having a reduced glass content. Sex porcelain has been proposed. According to this publication, a green sheet made of alumina and glass is fired in a non-oxidizing atmosphere, a Cu paste is printed on this substrate, and the firing is performed again in a non-oxidizing atmosphere.

[0006]

However, in the porcelain disclosed in Japanese Patent Publication No. 4-75868, although expensive glass powder is not used, the product cost can be reduced, but it is necessary to use a specific composite oxide. Since the natural minerals with high α-count, such as dumbrite, petalite, and forsterite, are used as the primary raw material powder, the α-count of the insulating porcelain finally becomes high, and IC etc. Sometimes the device does not work properly when the above device is installed. Moreover, the strength of the porcelain depends on the strength of these components, and further strength improvement cannot be expected.

Further, in JP-A-5-7060, the glass amount can be reduced by using a glass having a low softening point, but only specific alumina can be used as a filler, and a large amount is blended, The material characteristics of the insulating porcelain are similar to those of alumina used as a filler, and the thermal expansion coefficient is about 7 × 10 ^-6 / ° C. The thermal expansion coefficient of the insulating porcelain is high and the matching of the thermal expansion coefficient with the silicon chip I had a problem with.

As described above, conventionally, in order to realize low temperature firing and cost reduction, the amount of glass is reduced by adding an improvement to the filler, or a glass having a specific composition is combined with a specific filler. As described above, the selectivity of the filler is greatly limited, and it is difficult to achieve the matching of the thermal expansion coefficient with the silicon chip in accordance with low temperature firing and cost reduction.

[0009]

Means for Solving the Problems As a result of repeated studies on the above-mentioned problems, the present inventors have found that the glass to be blended has a yield point of 400 to 600 ° C. By using a glass having a low yield point, the sinterability at a low temperature can be enhanced, so that the content of the filler is mixed as much as 50 to 80% by volume, in other words, a small amount of glass is added to perform a dense sintering. It was found that the cost of porcelain can be reduced because the body can be obtained. Moreover, when such a glass is used, low temperature firing can be realized even if all the fillers are used. Therefore, if a filler with a low thermal expansion is selected as a filler, the consistency of thermal expansion with the silicon chip is also achieved. I knew I could do it.

That is, the insulating porcelain of the present invention is 40-40
The linear thermal expansion coefficient at 0 ° C. is 8 ppm / ° C. or less, and the deformation point is 20 to 50% by volume of Pb-free crystalline glass having a deformation point of 400 ° C. to 600 ° C., and the linear thermal expansion coefficient at 40 to 400 ° C. is 8 ppm / ° C. A porcelain obtained by sintering a mixture containing the following metal oxide fillers in an amount of 50 to 80% by volume, wherein the linear thermal expansion coefficient at 40 to 400 ° C is 6.5 ppm / ° C or less. It is what

The multilayer wiring board of the present invention is a multilayer wiring board having a conductor containing copper as a main component inside or on the surface of an insulating porcelain, wherein the insulating porcelain has a thickness of 40-40.
The linear thermal expansion coefficient at 0 ° C. is 8 ppm / ° C. or less, and the deformation point is 20 to 50% by volume of Pb-free crystalline glass having a deformation point of 400 ° C. to 600 ° C., and the linear thermal expansion coefficient at 40 to 400 ° C. is 8 ppm / ° C. A porcelain obtained by sintering a mixture containing the following metal oxide fillers in an amount of 50 to 80% by volume, wherein the linear thermal expansion coefficient at 40 to 400 ° C is 6.5 ppm / ° C or less. It is what

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. The insulating porcelain in the present invention is composed of a crystalline glass component and a filler component. As crystalline glass, 40-
A linear thermal expansion coefficient at 400 ° C. of 8 ppm / ° C. or less, a yield point of 400 ° C. to 600 ° C., a crystalline glass that does not contain Pb is used, and the filler component is a metal having a linear thermal expansion coefficient of 8 ppm / ° C. or less. An oxide is used.

Here, the linear thermal expansion coefficient of the crystalline glass at 40 to 400 ° C. is limited to 8 ppm / ° C. or less. When the linear thermal expansion coefficient is larger than 8 ppm / ° C., the linear thermal expansion of the whole insulating porcelain is limited. The coefficient has a large difference from the coefficient of thermal expansion of the silicon chip, and the difference in thermal expansion easily causes a connection failure between the silicon chip and the insulating porcelain. Desirably, it is 6 ppm / ° C. or less.

Further, the yield point of crystalline glass is 400.degree.
The reason for limiting the temperature to 600 ° C is that if the yield point is lower than 400 ° C, the porcelain will be densified below 900 ° C, and it will not be possible to co-fire with Cu that will become the conductor, and the yield point will be 600 ° C.
This is because if it is higher, the sintering temperature of the insulating porcelain becomes higher than 1050 ° C. and co-firing with Cu cannot be performed. It is preferably 400 to 550 ° C.

On the other hand, the reason why the linear thermal expansion coefficient of the filler at 40 to 400 ° C. is limited to 8 ppm / ° C. or less is that when the linear thermal expansion coefficient is larger than 8 ppm / ° C., the insulating property is the same as in the case of crystallized glass. This is because the coefficient of linear thermal expansion of the whole porcelain becomes larger than that of the silicon chip.

The above-mentioned crystallized glass and filler are 20 to 50% by volume, particularly 20 to 45% by volume of crystallized glass,
Further, 20 to 35% by volume, the filler is 50 to 80% by volume, particularly 55 to 80% by volume, and further 65 to 80% by volume. This is 20% by volume of crystalline glass
This is because if the amount is less, that is, if the amount of filler is more than 80% by volume, the densification temperature of the insulating porcelain becomes higher than 1050 ° C. and co-firing with Cu is not possible.
This is because when it is more than 0% by volume, that is, when the filler is less than 50% by volume, the densification temperature of the porcelain becomes lower than 900 ° C. and the bending strength of the porcelain becomes lower than 230 MPa.

It is also necessary that the crystalline glass does not contain Pb. This is because Pb is toxic and requires a special device and control for preventing poisoning during the manufacturing process, so that the sintered body cannot be manufactured at low cost. In addition, if Pb is contained in the glass, the yield point tends to be greatly lowered, and it becomes difficult to control the yield point within the above range. Considering the case where Pb is inevitably mixed as an impurity, the amount of Pb is 0.0
It is preferably 5% by weight or less.

The crystalline glass satisfying the above characteristics is not particularly limited as long as it satisfies the above characteristics. For example, BaO--B ₂ O ₃ --SiO _{2
2 -ZnO-Na 2 O-Al} 2 O 3, SiO 2 -B 2 O
_{3 -ZnO-Na 2 O-CaO} -Al 2 O 3 -K 2 O,
_{SiO 2 -Al 2 O 3 -Li 2} O-ZnO-K 2 O and the like. These crystalline glasses are crystallized into barium silicate (BaO · 2SiO ₂ ), uremanite (2ZnO · SiO ₂ ), lithium silicate, etc. after sintering.

Further, as the filler satisfying the above-mentioned characteristics, cordierite, spinel, stearite, anorthite, gerenicite, alumina, mullite, spodumene having a coefficient of linear thermal expansion of 40 to 400 ° C. of 8 ppm / ° C. or less can be mentioned. To be Of these, alumina is the most desirable in terms of strength, but alumina has a thermal expansion coefficient of 7 ppm.
Since it is relatively high at / ° C, mullite or the like is preferable in consideration of the matching of thermal expansion with the silicon chip. In the present invention, low temperature firing is possible even if any filler is used. Therefore, it is desirable to use synthetic raw materials as the filler. This is a natural mineral, generally α
This is because, since the count is high, the inclusion of such a filler having a high α-count may cause a malfunction of the element when used as a substrate on which a semiconductor is mounted.

The above-mentioned crystallized glass and filler are blended in the above composition range, and then the mixture is subjected to a desired molding means, for example, a sheet molding method such as a doctor blade method, a rolling method, a die press, a cold press. After being formed into an arbitrary shape by isostatic pressing, extrusion molding, etc., it is fired.

The firing is performed at 900 to 1050 ° C., particularly 900 to 1 in an oxidizing atmosphere such as air or a nitrogen atmosphere.
Bake at a temperature of 000 ° C. When producing a substrate on which a wiring conductor made of Cu is formed, this porcelain needs to be baked in nitrogen because Cu is oxidized in an oxidizing atmosphere.

The case of producing a multilayer wiring board in which a conductor mainly composed of Cu is arranged will be described more specifically. Such a multilayer wiring board is manufactured by, for example, forming a green sheet by molding a mixture of the above-mentioned crystallized glass and a filler by a sheet molding method such as a doctor blade method, and then forming a Cu powder on the surface of the green sheet. Is printed by a screen printing method or the like so that the Cu paste and the wiring pattern are dispersed. At this time, in the green sheet, Cu is formed in the hole where the through hole is formed.
It can also be filled with paste. The green sheets thus produced are laminated and pressure-bonded to produce a laminate.

Then, the laminated body is subjected to de-dinder treatment at 800 ° C. or lower in a nitrogen humidified atmosphere, and then 900-
By firing in a dry atmosphere in nitrogen at a temperature of 1050 ° C., particularly 900 to 1000 ° C., insulating porcelain and Cu
It is possible to sinter with the conductor at the same time. In this way, a multilayer wiring board can be manufactured.

[0024]

According to the present invention, the use of a crystallized glass having a yield point of 400 to 600 ° C. lower than that of the conventionally used glass increases the sinterability at a temperature of 900 to 1050 ° C. The amount of expensive glass occupying can be reduced, and thus the manufacturing cost can be significantly reduced. As a result, the content of the filler can be increased, and as a result, the strength of the porcelain can be increased.

Further, as a result that the selectivity for the filler can be expanded, 40 to 40 as the filler and the crystallized glass can be obtained.
By combining components having a linear thermal expansion coefficient of 0 ppm / ° C. or less at 0 ° C., it becomes possible to manufacture a porcelain having a linear thermal expansion coefficient of 6.5 ppm / ° C. or less. Can be approximated to the coefficient of thermal expansion.

Further, since such a porcelain can be fired at 900 to 1050 ° C., it can be fired at the same time as the wiring conductor made of Cu, and as a result, an inexpensive and highly reliable multilayer wiring board can be provided. Furthermore, in the insulating porcelain of the present invention, if a synthetic raw material other than natural minerals is used as the metal oxide used as the filler component, the α-count in the insulating porcelain can be lowered, and IC etc. Even if the device is mounted, the device is not adversely affected.

[0027]

EXAMPLES The insulating porcelain of the present invention will be described in detail below based on examples. As glass, the following weight ratios and yield points, linear thermal expansion coefficient at 40 to 400 ° C (ppm / ° C) Yield point thermal expansion coefficient Composition (° C) (ppm / ° C) 43% BaO-30% B _{2 O 3 -19% SiO 2 520 5.0} -4% ZnO-3% Na 2 O-1% Al 2 O 3 60% SiO 2 -20Al 2 O 3 -9% Li 2 O 450 5.4 -6% _{ZnO-5% K 2 O 50} % SiO 2 -18% B 2 O 3 -13% ZnO 600 5.9 -8% Na 2 O-6% CaO 60% PbO-10% B 2 O 3 -14% ZnO 350 9.2-10% SiO ₂ -6% Al ₂ O ₃ four kinds of glass, and as a filler component, alumina made of a synthetic raw material (coefficient of linear thermal expansion at 40 to 400 ° C. 7 ppm / ° C.), mullite (Linear thermal expansion coefficient of 40-400 ° C 4ppm / ° C) (Coefficient of linear thermal expansion of 40 to 400 ° C. 2.5 ppm / ° C.) and cordierite (coefficient of linear thermal expansion of 40 to 400 ° C. 2.4 ppm / ° C.) were weighed and prepared to have the composition shown in Table 1. . A paraffin wax was used as a binder in the composition weighed as described above to obtain a molded body by press molding.
An insulating porcelain was obtained by firing at a temperature of 00 to 1050 ° C.

Next, the coefficient of linear thermal expansion at 40 to 400 ° C. was measured on the insulating porcelain obtained as described above.
In addition, an evaluation sample is manufactured by processing the insulating porcelain into a shape having a diameter of 60 mm and a thickness of 2 mm, and the evaluation sample is used to measure JI.
The dielectric constant and dielectric loss tangent were measured under the measurement conditions of a frequency of 1 MHz and an input signal level of 1.0 Vrms in accordance with the specifications of S-C-2141.

Similarly, the insulating porcelain has a diameter of 60 mm,
An evaluation sample processed into a shape having a thickness of 2 mm was prepared, and the volume resistivity was measured by this evaluation sample under the measurement conditions of voltage number V to 1000 V according to the regulations of JIS-C-2141.

Further, an evaluation sample was produced by processing the above-mentioned insulating porcelain into a shape having a length of 70 mm, a thickness of 3 mm and a width of 4 mm, and the bending strength (3) was prepared from the evaluation sample according to JIS-C-2141. The point bending test) was measured. Table 2 shows the results.

The α count of each sample, which is an example of the present invention, was measured by the gas flow proportional coefficient tube method.
It was 0.1 DPH / cm ² , and it was confirmed that the α count was low.

[0032]

[Table 1]

According to the results shown in Table 1, in the sample No. 20 using glass having a yield point higher than 600 ° C., if the glass amount does not exceed 50% by volume, it is sufficiently dense at a low temperature of 900 to 1050 ° C. No.17, 1
In Nos. 8, 19, and 20, the firing temperature was high, the simultaneous firing with Cu was not possible, and the strength was low even though the densification was possible. Further, in sample No. 21 using glass having a yield point lower than 400 ° C., sintering was performed at 750 ° C. or lower, and co-firing with Cu was not possible.

On the other hand, the yield point is 400 to 600 ° C.
When the glass of No. 2 was used, it was possible to densify at a low temperature even if the amount of glass was 50% by volume or less. Moreover, by appropriately combining fillers and glasses having a thermal expansion coefficient of 8 ppm / ° C. or less, the thermal expansion coefficient of the entire porcelain can be approximated to 4 ppm / ° C. of the silicon chip. Also, since the amount of filler has increased, the bending strength is also 230
MPa or more, especially 65% by volume of alumina as a filler
In the samples No. 4 and 5 containing the above, 300 MPa or more was achieved. As a result of using mullite, anorthite, or cordierite as the filler, the linear thermal expansion coefficient was 3.2 to 4.8 while maintaining the bending strength of 230 MPa or more.
It was possible to control to ppm / ° C.

Example 2 A slurry was prepared by adding and mixing a binder, a plasticizer and a solvent to the composition of the sample of the present invention shown in Table 1. An acrylic resin was used as the binder, DBP (dibutyl phthalate) was used as the plasticizer, and toluene was used as the solvent.

The slurry prepared as described above is applied to the release film by a doctor blade method in an amount of 0.1 to 0.5.
It was poured so as to have a thickness of mm, and the solvent was dried and removed to obtain a green sheet having a predetermined thickness.

Then, a wiring paste for evaluation is thick-film printed on the surface of the green sheet by a screen printing method using a conductor paste containing copper as a main component, and after drying, the green sheet having the wiring pattern for evaluation is used as the surface. Ten green sheets were laminated and pressure-bonded.

This laminate is heated in a nitrogen atmosphere containing water vapor to decompose and remove the binder and plasticizer in the green sheet laminate, and then debinding is performed at 700 to 800 ° C., and then dry nitrogen atmosphere. Below 900
It was baked at 1050 ° C.

As a result, it was possible to obtain a multilayer wiring board with good adhesion and precision by co-firing with any of the samples the Cu metallized wiring layer.

[0040]

As described in detail above, according to the present invention,
By using a crystallized glass having a low yield point, it is possible to fire at a low temperature and with a small amount of glass.
It is possible to inexpensively manufacture a multi-layered wiring board using as a wiring conductor. Also, since a large amount of filler can be added,
The strength of the porcelain can be increased, which makes it possible to manufacture a highly reliable multilayer wiring board.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiko Higashi, 1-4 Yamashita-cho, Kokubun-shi, Kagoshima Prefecture Kyocera Stock Company Research Institute (72) Inventor Yasuhide Minami 1-4, Yamashita-cho, Kokubun-shi, Kagoshima Kyocera Incorporated Research Institute

Claims (2)

[Claims] 1. The coefficient of linear thermal expansion at 40 to 400 ° C. is 8.
20% to 50% by volume of Pb-free crystalline glass having a yield point of 400 ° C. to 600 ° C.
A porcelain obtained by molding and firing a mixture in which a filler composed of a metal oxide having a linear thermal expansion coefficient at 400 ° C of 8 ppm / ° C or less is mixed at a ratio of 50 to 80% by volume,
Linear thermal expansion coefficient at 40 to 400 ° C is 6.5 ppm /
Insulating porcelain characterized by being below ℃. 2. A multilayer wiring board having a conductor containing copper as a main component inside or on the surface of an insulating porcelain, wherein the insulating porcelain has a linear thermal expansion coefficient of 8 p at 40 to 400 ° C.
20 to 50% by volume of Pb-free crystalline glass having a deformation point of pm / ° C or less and a yield point of 400 ° C to 600 ° C, and 40 to 4
A porcelain obtained by molding and firing a mixture in which a filler made of a metal oxide having a linear thermal expansion coefficient at 00 ° C. of 8 ppm / ° C. or less is mixed at a ratio of 50 to 80% by volume.
Coefficient of linear thermal expansion at 0-400 ℃ is 6.5ppm / ℃
A multilayer wiring board characterized by the following.