JPH10194846A - Production of substrate fired at low temperature - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the percentage of a crystal phase in a glass-ceramic substrate and to obtain a substrate fired at a low temp. and excellent in mechanical and dielectric characteristics, the coefft. of thermal expansion, etc., by using crystalline aggregate powder having a specified specific surface area. SOLUTION: When the objective substrate fired at a low temp. is produced using glass powder and crystalline aggregate powder, crystalline aggregate powder having 4-15m<2> /g, preferably 6-12m<2> /g specific surface area is used. The kind of the glass powder is not especially limited and CaO-Al2 O3 -SiO2 -B2 O3 glass or borosilicate glass is, e.g. used. The king of the crystalline aggregate powder is not also especially limited and alumina or anorthite, etc., is used. The substrate is produced, e.g. by mixing 50-65 pts.wt. glass powder contg. 10-55wt.% CaO, 0-30wt.% Al2 O3 , 45-70wt.% SiO2 and 0-20wt.% B2 O3 with 50-35 pts.wt. Al2 O3 powder having 4-15m<2> /g specific surface area and then firing the resultant mixture at 800-1,000 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a low-temperature fired substrate, and more particularly, to a method for manufacturing a low-temperature fired substrate used for mounting electronic components.

[0002]

2. Description of the Related Art Alumina multilayer substrates, which have been widely used as ceramic substrates on which electronic components such as LSIs are mounted, have a high firing temperature of about 1550 ° C., so that W or Mo having a high melting point is used for the internal conductor. Must be used. However, since W and Mo have large specific resistance, signal transmission loss in the alumina multilayer substrate increases. In addition, the relative dielectric constant (ε _r ) of alumina is usually as large as 8 to 10, so that the signal delay also becomes large.

With the recent increase in the speed of signal processing in electronic equipment, transmission loss and signal delay of signals occurring in a multilayer substrate have become a serious problem, and a multilayer substrate with small transmission loss and signal delay has been demanded. I have.

[0004] From such a background, in recent years, low-temperature fired substrates having a low relative dielectric constant and containing glass that softens and sinters at low temperatures and crystalline ceramics as components have been attracting attention. Since the low-temperature fired substrate can be densified at a firing temperature of 950 ° C. or lower, use of Ag, Cu, Au, an Ag—Pd alloy or the like having a low specific resistance and a small transmission loss as the internal conductor material is used. Can be. In addition, since these metals and the surrounding glass ceramics have a small relative dielectric constant, they have various advantages such as a reduction in signal delay of wiring.

Generally, a low-temperature fired substrate is manufactured by the following method. First, a slurry is prepared by adding a resin (binder), an organic solvent, and the like to a mixed powder of a glass powder and an inorganic material powder called a crystalline aggregate, and a green sheet is prepared using the slurry by a doctor blade method or the like. I do.

Next, the green sheet is subjected to a processing such as punching as required, and a conductor paste layer having a predetermined pattern is formed on the surface thereof by using a conductor paste mainly composed of a conductor such as Ag, thereby forming a via hole. Is filled with a conductive paste.

Next, the green sheets subjected to these treatments are laminated and thermocompressed to form a green sheet laminate, which is degreased and fired in the air to produce a glass ceramic substrate (sintered body). , If necessary, plating
Complete the low-temperature fired substrate. There is also a method in which a glass-ceramic substrate having only an internal conductor layer is once manufactured by firing, and then a conductor paste layer is formed on the surface of the glass ceramic substrate, and a process such as baking is performed to form external connection pads and the like.

The low-temperature fired substrate manufactured by the above method contains a glass phase and a crystal phase, and this crystal phase contains a part of the crystalline aggregate powder used as a raw material. In addition, it contains the same or different crystal phase as the crystalline aggregate precipitated during the firing process. For low temperature fired substrates, 950
Since it is fired at a low temperature of ℃ or lower, it is essential to generate a glass phase that softens at a low temperature, but it is difficult to obtain necessary properties (mechanical strength, thermal expansion coefficient, relative permittivity, etc.) with the glass phase alone. Therefore, a crystalline aggregate powder is added. But,
When the amount of the crystalline aggregate powder is large, sintering becomes difficult, and therefore the amount of the crystalline aggregate powder is limited. Therefore, conventionally, a method has been adopted in which a new crystal phase is precipitated in the firing process to improve mechanical properties (flexural strength, etc.) and also control other material properties (thermal expansion coefficient, dielectric constant, etc.). As a control method, a method of reducing the average particle size of the raw material powder or increasing the firing temperature has been adopted.

[0009]

However, if an attempt is made to reduce the average particle size of the raw material powder to increase the amount of the crystal phase precipitated, the state of filling of the raw material powder in the slurry during the slurry adjustment deteriorates. Handling properties such as when manufacturing a green sheet are deteriorated, and the shrinkage rate during firing is increased due to the deterioration of the filling state of the raw material powder in the green sheet, and a low-temperature fired substrate having good various properties is obtained. There was a problem that manufacturing became difficult.

Further, if the amount of the crystal phase is increased by increasing the firing temperature, a mismatch occurs in the processing temperature with the metal conductor formed inside or on the surface or the dielectric material for the capacitor formed inside, etc. Also in this case, there is a problem that it becomes difficult to manufacture a low-temperature fired substrate having good various characteristics.

The present invention has been made in view of the above problems, and it is an object of the present invention to increase the ratio of the crystal phase in a glass ceramic substrate without changing the average particle diameter of the raw material powder and the sintering temperature so much as in the conventional case. It is an object of the present invention to provide a method of manufacturing a low-temperature fired substrate capable of manufacturing a low-temperature fired substrate excellent in various properties such as mechanical properties, dielectric properties, and thermal expansion coefficient.

[0012]

In order to achieve the above object, a method of manufacturing a low-temperature fired substrate according to the present invention (1) is a method of manufacturing a low-temperature fired substrate using glass powder and crystalline aggregate powder. In the production method, the specific surface area is 4 to 15 m ^2.
/ G of crystalline aggregate powder.

In the method (2) for producing a low-temperature fired substrate according to the present invention, a crystalline aggregate powder having a specific surface area of 6 to 12 m ² / g is used in the method (1) for producing a low-temperature fired substrate. It is characterized by:

According to the low-temperature fired substrate manufacturing method (1) or (2), since the crystalline aggregate powder having a large specific surface area is used, the area of the crystalline aggregate in contact with the glass phase becomes large. In the firing process, a crystal phase is precipitated from the boundary surface of the crystalline aggregate in contact with the glass phase, and a low-temperature fired substrate having a high crystal phase ratio can be manufactured. as a result,
A low-temperature fired substrate excellent in various characteristics such as a mechanical characteristic and a coefficient of thermal expansion can be manufactured.

The low-temperature fired substrate manufacturing method (3) according to the present invention is the same as the low-temperature fired substrate manufacturing method (1) or (2), except that the glass powder is CaO-Al ₂ O _3.
Cold containing -SiO ₂ -B ₂ O ₃ based glass, using Al ₂ O _3, respectively as a crystalline aggregate powder, Al ₂ O ₃ and _{CaO · Al 2 O 3 · 2SiO} 2 as the crystalline layer (anorthite) It is characterized by producing a fired substrate.

The low-temperature fired substrate manufacturing method (4) according to the present invention is the same as the low-temperature fired substrate manufacturing method (3), except that CaO is 10 to 55 wt% and Al ₂ O ₃ is 0 to 30 wt%.
wt%, a SiO ₂ 45~70wt%, the B ₂ O ₃ 0 to
After mixing 50 to 35 parts by weight of Al ₂ O ₃ powder having a specific surface area of 4 to 15 m ² / g with respect to 50 to 65 parts by weight of glass powder contained in the range of 20 wt%, 800 to 1 part by weight
It is characterized by firing at a temperature of 000 ° C.

According to the low-temperature fired substrate manufacturing method (3) or (4), CaO—Al ₂ O ₃ —SiO ₂ —B ₂ O close to the anorthite component is used as the glass powder material.
_Since an Al ₂ O ₃ powder having a large specific surface area is used as a crystalline aggregate powder using a ₃ series glass, a crystal phase of anorthite is easily precipitated from a boundary surface of the Al ₂ O ₃ in contact with the glass phase. Thus, a low-temperature fired substrate having a high anorthite crystal phase ratio can be manufactured. As a result, a low-temperature fired substrate excellent in various properties such as mechanical properties and thermal expansion coefficient can be manufactured.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for manufacturing a low-temperature fired substrate according to the present invention will be described.

In the method for manufacturing a low-temperature fired substrate according to the embodiment, glass powder and crystalline aggregate powder are used as raw materials for forming a glass ceramic layer.

The type of the glass powder is not particularly limited, and the same type as in the conventional case can be used. Specifically, for example, CaO-Al ₂ O ₃ -
SiO ₂ -B ₂ O ₃ based glass, MgO-Al ₂ O ₃ -S
_{iO 2 -B 2 O 3 -R 2} O -based glass (the R represents an alkali metal), and a borosilicate glass. CaO-
In the case of using the _{Al 2 O 3 -SiO 2 -B 2} O 3 based glass, 10~55wt% of CaO, the Al ₂ O ₃ 0 to 3
0 wt%, 45 to 70 wt% of SiO ₂ , and 0 of B ₂ O ₃
Glass powder having an average particle size of 2 to 5 μm contained in the range of 20 wt% is preferred.

The type of the crystalline aggregate powder is not particularly limited, and the same type as in the prior art can be used. Specifically, for example, Al ₂ O ₃ (alumina),
CaO.Al ₂ O ₃ .2SiO ₂ (anorthite), 2
MgO · 2Al ₂ O ₃ · 5SiO ₂ crystals (cordierite), 3Al ₂ O ₃ · 2SiO ₂ (mullite), etc., and the specific surface area of these crystalline aggregate powders is 4 to 15
m ² / g, preferably using those 6~12m ² / g. The reason for selecting the crystalline aggregate powder having a large specific surface area as described above is that, by using the crystalline aggregate powder having a large specific surface area, these crystalline aggregate powders act as crystal nuclei at the time of sintering, and from the glass. Promotes the precipitation of the crystalline phase of
This is for producing a low-temperature fired substrate having excellent mechanical properties and the like.

For example, as a glass powder, CaO-Al ₂
When an O ₃ —SiO ₂ —B ₂ O ₃ system glass is used and Al ₂ O ₃ is used as the crystalline aggregate powder, an anorthite crystal phase can be precipitated. By using a material of 15 m ² / g, the ratio of anorthite in the manufactured glass-ceramic substrate can be set to a preferable range as a low-temperature firing material.

Conditions other than the above conditions are not particularly different from those in the conventional case. First, a binder, a solvent, a plasticizer, and the like are added to powder mixed with glass powder and crystalline aggregate powder and mixed. And a slurry is prepared, and a green sheet is prepared using the slurry by a doctor blade method or the like. Next, the green sheet is cut into a predetermined size, and if necessary, a processing such as punching is performed.
After applying or filling a conductive paste containing a metal such as a Pd alloy, the resultant is laminated and thermocompression-bonded to produce a green sheet laminate. After the above steps, 1-800 ° C. and 950 ° C.
Firing for 0 minutes to 10 hours to produce a low-temperature fired multilayer wiring board in which a glass-ceramic layer composed of a glass phase and a crystal phase is formed, and a conductor layer is formed inside and / or on the surface.

The low-temperature fired substrate manufactured by the above method can have a transverse rupture strength of 2000 kgf / cm ² or more, and can be excellent in various properties such as relative dielectric constant and coefficient of thermal expansion.

[0025]

Examples and Comparative Examples Examples of the method for manufacturing a low-temperature fired substrate according to the present invention will be described below. As a comparative example,
A case where a low-temperature fired substrate is manufactured using a conventional raw material will also be described.

In this example and comparative examples, green sheets containing glass powder and crystalline aggregate powder were prepared.
This was punched out with a 50 mm × 40 mm mold, fired, tested for various characteristics, and evaluated as a sintered body for a low-temperature fired substrate.

(1) Manufacturing conditions Glass powder Type of glass powder: CaO—Al ₂ O ₃ —SiO ₂ —B
₂ O ₃ -based glass Composition of glass powder CaO: 25 wt%, Al ₂ O ₃ : 6 wt%, SiO
_{2: 60wt%, B 2 O} 3: 9wt% crystalline aggregate powder crystalline aggregate powder Type: Al ₂ O ₃ and milling process pretreatment ball mill crystalline aggregate powder (Al ₂ O ₃ powder) , Different in specific surface area A
l ₂ O ₃ powder was prepared. Pulverization time, average particle size of pulverized Al ₂ O ₃ powder, and specific surface area (BET
(Value: m ² / g) are shown in Table 1 below. BET value measurement method: N ₂ adsorption method (Flowsorb II manufactured by Micrometrics) Mixing of glass powder and crystalline aggregate powder Ratio of each powder in mixed powder Glass powder: 60 wt%, alumina powder: 40 wt%, mixing Average particle size of powder: shown in Table 1. Measurement of average particle size of powder (alumina powder, mixed powder) Particle size analyzer using laser diffraction method (Microtrack manufactured by Nikkiso Co., Ltd.) Preparation of green sheet Components in slurry: mixed powder, resin (methyl methacrylate), Solvent (toluene, xylene, butanol), plasticizer (dioctyl adipate (DOA)) Molding method: doctor blade method Ratio of mixed powder in green sheet: 60 wt% Green sheet thickness: 400 μm Firing Firing atmosphere: air atmosphere Temperature rise Conditions: 200 ° C./hr Firing conditions: 890 ° C., 20 minutes (2) Evaluation method The following three items were evaluated for the manufactured sintered body. The results are shown in Table 1 below.

Measurement of the Anorthite Crystal Deposition The X-ray intensity of the precipitated anorthite crystal was measured by an X-ray diffraction method. Table 1 shows the peak intensity (arbitrary unit) of the anorthite crystal.

Measurement of Thermal Expansion Coefficient The thermal expansion coefficient from room temperature to 250 ° C. was measured by a contact type linear expansion coefficient meter, and the average value was taken.

[0030] Warping during post-installation heat treatment [0030] A conductor paste is printed on both surfaces of the manufactured sintered body, and the inside of a post-fixing jig having a semicircular cross section so that the printed conductor paste layer does not contact the bottom surface. The sintered body was placed thereon, and heat treatment was performed, and the warpage generated in the sintered body due to the heat treatment was measured. If the substrate is warped during post-installation firing, it cannot be used as a substrate. Therefore, the warpage is preferably 0.5 mm or less, more preferably 0.1 mm or less. Therefore, when the warp is 0.1 mm or less, the warp is
Those exceeding mm were rated as Δ, and those exceeding 0.5 mm were rated X.

[0031]

[Table 1]

(3) Evaluation results As shown in Table 1 above, the crystalline aggregate powder Al ₂
As the BET value of the O ₃ powder increases, the amount of anorthite crystal increases, and the values of the thermal expansion coefficient and the like also decrease as compared with the comparative example. In addition, due to its excellent heat resistance, warpage during post heat treatment is also small,
It shows sufficient characteristics as a glass ceramic layer constituting a low-temperature fired substrate. On the other hand, the average particle size of the crystalline aggregate powder and the mixed powder does not change so much, and green sheets can be produced under substantially the same conditions as in the related art.

As described above, according to the method for manufacturing a low-temperature fired substrate according to the embodiment, the CaO-Al
The average particle size of ₂ O ₃ —SiO ₂ —B ₂ O ₃ -based glass powder or Al ₂ O ₃ , which is a crystalline aggregate powder, is not significantly changed, and therefore, the manufacturing conditions and firing conditions of the molded body are also significantly changed. Without changing the BET value of the crystalline aggregate powder from 4 to 12.
By increasing it to 9 m ² / g, the ratio of the crystal phase (alumina, anorthite) in the glass ceramic substrate is large, and a low-temperature fired substrate excellent in various properties such as mechanical properties, dielectric properties, and coefficient of thermal expansion is manufactured. can do.

Claims (4)

[Claims] 1. A method for producing a low-temperature fired substrate using a glass powder and a crystalline aggregate powder, wherein the specific surface area is 4 to 15
A method for producing a low-temperature fired substrate, comprising using m ² / g of crystalline aggregate powder. 2. The method for producing a low-temperature fired substrate according to claim 1, wherein a crystalline aggregate powder having a specific surface area of 6 to 12 m ² / g is used. 3. A glass powder comprising CaO--Al ₂ O _3-
SiO ₂ -B ₂ O ₃ based glass, A as a crystalline aggregate powder
_3. A low-temperature fired substrate containing l ₂ O ₃ and containing Al ₂ O ₃ and CaO.Al ₂ O ₃ .2SiO ₂ (anorthite) as a crystal layer is manufactured. The method for producing the low-temperature fired substrate according to the above. 4. 10～55Wt% of CaO, Al ₂ O ₃
The 0~30wt%, the SiO ₂ 45~70wt%, B ₂
Glass powder 50 containing O ₃ in the range of 0 to 20 wt%
A having a specific surface area of 4 to 15 m ² / g with respect to
After mixing l ₂ O ₃ powder at a ratio of 50-35 parts by weight,
4. The method according to claim 3, wherein the substrate is fired at a temperature of 800 to 1000 [deg.] C.