JP2002299820A - Method of manufacturing ceramic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass ceramic component which is highly reliable and capable of preventing defects such as cracking and the like from occurring around internal electrodes in a burned board without deteriorating its electrical properties so much in a high dimensional accuracy burning technique of burning a glass ceramic laminate sandwiched in between thermal shrinkage control sheets. SOLUTION: Conductor paste contains conductor powder which contains 95 wt.% or above Ag powder and organic vehicles, and the total quantity of glass ceramic mixed powder of glass powder and ceramic powder amounts to 0.1 to 10 wt.% of the conductor powder and is contained in the conductor paste. Or, conductor powder containing 95 wt.% or above Ag powder and organic vehicles are contained in conductor paste, and furthermore glass powder which has a softening point of 750 deg.C or above and amounts to 0.1 to 10 wt.% is contained in the conductor paste.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a method for manufacturing a ceramic component, such as a ceramic multilayer substrate for mounting chip components and interconnecting them.

[0002]

2. Description of the Related Art In recent years, semiconductor LSIs, chip components, and the like have been reduced in size and weight, and it has been desired to reduce the size and weight of wiring boards on which they are mounted. In response to such demands, ceramic multilayer substrates are regarded as important in today's electronics industry because they can provide the required high-density wiring and can be made thinner.

A conventional method for manufacturing this ceramic multilayer substrate will be described. Generally, a ceramic multilayer substrate is produced by (1) a step of preparing and mixing ceramic materials, (2) a step of forming a ceramic green sheet, (3) a step of forming a conductor paste, and (4) a step of firing a composite laminate.

[0004] In the firing step, the ceramic multilayer substrate contracts due to sintering. The shrinkage accompanying this sintering is
It depends on the substrate material used, green sheet composition, powder lot, etc. This causes several problems in the fabrication of a multilayer substrate. For example, in order to form the uppermost layer wiring after firing the inner layer wiring in the production of the ceramic multilayer substrate, if the contraction error of the substrate material is large,
Connection with the inner layer electrode cannot be performed due to the dimensional error of the uppermost layer wiring pattern. As a result, a land having an unnecessarily large area must be formed in the uppermost electrode portion so as to allow a shrinkage error in advance, and it cannot be used for a circuit requiring high-density wiring. For this reason, a method of preparing several screen plates for the uppermost layer wiring in accordance with the contraction error and using the screen plate in accordance with the contraction ratio of the substrate may be adopted. This method is expensive because many screen versions must be prepared. Also, if the top layer wiring is performed at the same time as the inner layer firing, a large land is not required. May not be able to print on the necessary parts.

In Japanese Patent No. 2785544, a desired number of green sheets formed of a low-temperature sintered glass-ceramic mixed powder and having an electrode pattern formed thereon are laminated, and the glass ceramic mixed powder is coated on both sides or one side of the laminate. Are laminated so as to be sandwiched between heat shrinkage suppressing green sheets (hereinafter, referred to as heat shrinkage suppressing sheets) made of an inorganic composition that does not sinter at the firing temperature of, and the laminate is fired. Thereafter, an invention was made to remove the heat shrinkage suppressing layer. As a result, a large amount of sintering of the substrate material occurs in the thickness direction, and a substrate in which shrinkage in the planar direction is suppressed can be manufactured.

[0006]

From the above, a substrate which is unlikely to contract in the plane direction has been manufactured, but there is a problem here. That is, since a large amount of substrate shrinkage occurs in the thickness direction, in the conventional manufacturing method, defects such as cracks occur around the internal electrodes in the fired substrate.

It is considered that the cause of this problem is largely due to a shift in the sintering timing or thermal shrinkage behavior between the conductor paste and the green sheet laminate during the firing process. Due to a large shift in the sintering shrinkage behavior between the green sheet laminate and the conductive paste, excessive stress and strain occur between the fired substrate and the electrode, and the above-described defects such as cracks occur. . According to the conventional manufacturing method, shrinkage occurs in the three-dimensional direction in the firing process, and the generated cracks are repaired during firing if they are minute, but in the manufacturing method of the present invention, the cracks shrink in the planar direction during the firing process. Since defects do not occur, it is difficult to repair defects such as cracks. If defects such as cracks occur in the substrate, there is a problem in that the reliability of the substrate is reduced.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a high dimensional precision firing method in which a glass ceramic laminate is sandwiched between heat shrinkage suppressing sheets and fired without greatly deteriorating electrical characteristics. Another object of the present invention is to provide a highly reliable glass-ceramic component that suppresses the occurrence of defects such as cracks around internal electrodes in a fired substrate.

[0009]

According to the present invention, there is provided a glass ceramic comprising a conductive paste comprising a conductive paste containing 95% by weight or more of Ag powder in the conductive paste and an organic vehicle. 0.1 to 10% by weight of the total of the conductor powder
Is included in the range.

[0010] Alternatively, glass having a softening point of 750 ° C or more containing 0.1% by weight or more of a conductive powder containing a conductive paste containing 95% by weight or more of Ag powder in the conductive paste and an organic vehicle is used. %.

The average particle size of the Ag powder in the conductor paste is preferably 2.9 μm or more.

In the firing step, the heating rate is 200
C./h or more is desirable.

[0013]

Embodiments of the present invention will be described below. First, a method for producing a glass ceramic mixed material will be described. The glass-ceramic mixed material used this time includes Al ₂ O ₃ , MgO, Sm ₂ O ₃ (hereinafter referred to as AMS) and glass (SiO ₂ —B ₂ O ₃ —CaO-based glass powder, softening point 780 ° C.). It is the main component. High-purity Al ₂ O ₃ , MgO, and Sm ₂ O ₃ raw material powders weighed at a molar ratio of 11: 1: 1 are put into a ball mill, mixed for 20 hours, and dried. 13
The calcined powder is calcined at 00 ° C for 2 hours, and the calcined powder is
What was ground for a time is AMS. This AMS and Si
O ₂ -B ₂ O ₃ were weighed -CaO based glass in a ratio of 50:50 by weight, was mixed for 20 hours by a ball mill, a glass ceramic mixed material used here by drying (hereinafter, referred to as AMSG) Is obtained. Since this AMSG is densely fired in a temperature range of 880 ° C. to 950 ° C.,
Simultaneous firing with a silver electrode is possible. The relative permittivity is 7.5 (1 MHz). Alumina powder (purity: 99.9%, average particle size: 1.0 μm) was used as a material for the heat shrinkage suppression green sheet.

A PVB resin as a binder and dibutyl phthalate as a plasticizer are added to the above AMSG and alumina powder, a slurry is prepared using butyl acetate as a solvent, and a slurry having a desired thickness is formed by a well-known doctor blade method.
SG green sheets and heat shrinkage-suppressed (alumina) green sheets were produced.

Next, a method of preparing the conductor paste will be described. Ag is added to the paste in an optional ratio with respect to 100% by weight of Ag, and an organic vehicle (a solution of terpineol in ethyl cellulose) is added in an amount of 20% by weight based on the whole paste. Obtained.

The conductor paste was printed as a pattern (conductor layer) 3 for measuring electric resistance on the green sheet using a screen printer. The required number of the AMSG green sheets 2 are laminated so that the configuration of FIG. 1 is obtained, and the alumina green sheets 1 are laminated on both sides. In this state, the laminate was formed by thermocompression bonding. The thermocompression bonding conditions were a temperature of 80 ° C. and a pressure of 500 kg / cm ² . This laminate is cut into a size of 10 × 10 mm, placed on an alumina sheath, and heat-treated at 500 ° C. for 10 hours in a box furnace to incinerate the resin component. , Holding time 30 minutes, heating rate 300 ° C
/ H (however, only in Example 4, the heating rate was changed).

The alumina of the heat shrinkage suppressing green sheet 1 remains on the surface of the fired laminate without firing, and was completely removed by ultrasonic cleaning in butyl acetate.

[0018]

EXAMPLES (Example 1) The conductor paste used here was:
Ag (average particle size 4.0 μm), glass constituting AMSG (SiO ₂ —B ₂ O ₃ —CaO-based glass powder, softening point 7
80 ° C., average particle size 2.0 μm) and AMS (average particle size 1.0 μm), and their compositions are as shown in (Table 1).

[0019]

[Table 1]

The results obtained by analyzing and evaluating the obtained ceramic multilayer substrate are shown in Table 1. In the evaluation items, “mode of defects such as cracks” refers to cracks and the like generated in the ceramic multilayer substrate 11 near the internal electrodes 12 by polishing the ceramic multilayer substrate 11 and observing the cross section with an optical microscope as shown in FIG. The evaluation was performed by classifying into a plurality of modes according to the degree of the defect 13.

In Table 1, "mode A" has no defect, "mode B" has a small defect length of less than 5 μm, and "mode C" has a large defect length of 5 μm or more. Things. `` Resistance value '' is obtained by applying a silver electrode paste to the side surface of the internal conductor layer and baking to form a terminal electrode, and measuring the DC resistance value using a digital multimeter,
The sheet resistance was calculated in terms of an electrode thickness of 10 μm.

Samples 2 to 7 had no defects 13 such as cracks (Mode A), but Sample 1 had defects 13 such as cracks (Mode C). This is because the sintering behavior of the ceramic laminate is reduced by delaying the sintering of the conductive paste during firing by containing the glass powder and the ceramic powder constituting the glass ceramic in the range of 0.1 to 10% by weight. This is because they can be matched. If the amount is less than 0.1% by weight, the sintering of the conductor paste cannot be delayed. Also, (Sample 1)-
(Sample 6) had a small resistance value, while (Sample 7) had an increased resistance value. This is because the glass powder or the ceramic powder becomes a current resistance. The glass powder and the ceramic powder satisfy the required performance in terms of both the defect mode and the resistance value.
0% by weight (Sample 2) to (Sample 6).

(Example 2) The paste used here was A
g (average particle size: 4.0 μm) and three types of glass (average particle size: about 2 μm), and their compositions and glass softening points are as shown in Table 2. The results of analyzing and evaluating the obtained ceramic multilayer substrate 11 are shown in (Table 2).

[0024]

[Table 2]

(Sample 9), (Sample 11), (Sample 1)
3) and (Sample 14) had no defect 13, but (Sample 8) had defect 13. This is because the sintering of the conductive paste at the time of firing can be delayed by including the glass powder in the range of 0.1 to 10% by weight. If the amount is less than 0.1% by weight, sintering cannot be delayed. Further, (Sample 8), (Sample 9), (Sample 11) and (Sample 13) had small resistance values, but (Sample 14) had increased resistance values. This is because the glass powder serves as a current resistance. Glass powder satisfying the required performance when viewed from both the defect mode and the resistance value is 0.1 to 10% by weight of the whole conductor powder (Sample 9), (Sample 11), ( Sample 13).

Although (Sample 11) and (Sample 12) had no defect 13, (Sample 10) had no defect 13.
Had occurred. This is because sintering cannot be delayed if the glass softening point is lower than 750 ° C. (Sample 10) to (Sample 12) all had low resistance values.
Those satisfying the required performance when viewed from both the defect mode and the resistance value were (Sample 11) and (Sample 12) having a glass softening point of 750 ° C. or more.

Example 3 Here, the influence of the particle size of Ag constituting the conductive paste was examined. As shown in (Table 3), Ag having an average particle size of 2.1 to 5.2 μm was used, AMS (average particle size 1.0 μm) was 1.0% by weight, and glass (SiO ₂ -B ₂
A conductor paste containing 1.0% by weight of an O ₃ —CaO-based glass powder, a softening point of 780 ° C. and an average particle size of 2.0 μm) was prepared and evaluated. The results of analyzing and evaluating the obtained ceramic multilayer substrate 11 are shown in (Table 3).

[0028]

[Table 3]

In Samples 16 to 18, no defect 13 occurred, but in Sample 15, a slight defect 13 occurred (mode B). This is because if the particle size is too small, the electrode shrinks faster than the green sheet during firing, and the electrode pulls the green sheet, causing defects 13 on the substrate 11 around the electrode. (Sample 15) ~
(Sample 18) had a small resistance value. Those satisfying the desired performance from both the defect mode and the resistance value were (Sample 16) to (Sample 18) in which the average particle diameter of the Ag powder was 2.9 μm or more.

Example 4 Here, the effect of the rate of temperature increase in the firing process was studied. The used paste is shown in (Sample 17) of (Table 3). Further, the heating rate this time is as shown in (Table 4). The results of analyzing and evaluating the obtained ceramic multilayer substrate 11 are shown in (Table 4).

[0031]

[Table 4]

No defects 13 occurred in (Samples 20) to (Sample 22), but defects 13 occurred slightly in (Sample 19). This is because the difference in shrinkage behavior between the electrode and the green sheet during firing is reduced by increasing the heating rate. (Sample 19) to (Sample 22) all had low resistance values. Those satisfying the desired performance in terms of both the defect mode and the resistance value were (Sample 20) to (Sample 22) whose heating rate was 200 ° C./h or more in the firing step.

As the glass-ceramic mixed powder, for example, AMSG may be used, but it is not particularly limited in the present invention, and a powder having an appropriate composition can be used as long as the intended effect is not violated.

[0034]

According to the method for manufacturing a ceramic component of the present invention, in a high dimensional accuracy firing method in which a glass ceramic laminate is sandwiched between heat shrinkage suppressing sheets and fired, the electrical characteristics after firing are not significantly deteriorated. It is possible to provide a highly reliable glass-ceramic component that suppresses the occurrence of defects such as cracks around the internal electrodes on the substrate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a high dimensional accuracy firing method in which a ceramic laminate is sandwiched between heat shrinkage suppressing sheets and fired.

FIG. 2 is a view for explaining a state in which a defect such as a crack has occurred in a ceramic component.

[Explanation of symbols]

 1 Thermal shrinkage suppression (alumina) green sheet 2 AMSG green sheet 3 Conductor paste

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hiroshi Kagata 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. 4G030 AA07 AA11 AA36 AA61 BA12 CA03 CA08 GA19 GA31 5E346 AA12 AA32 CC18 CC39 EE22 EE27 EE29 HH11

Claims (5)

[Claims] 1. A method of manufacturing a ceramic component by laminating and firing a plurality of green sheets made of a glass-ceramic mixed powder, comprising: a conductive powder containing at least an Ag powder; and an organic vehicle. The glass powder and the ceramic powder constituting the mixed powder are combined to form a powder of 0.1% of the entire conductor powder.
A step of preparing a conductor paste containing 1 to 10% by weight; a step of forming a composite laminate obtained by laminating a conductor layer made of the conductor paste and the green sheet; A step of arranging a heat shrinkage suppressing green sheet made of an inorganic composition that does not sinter at the firing temperature of the glass-ceramic mixed powder on one surface to obtain a firing laminate; and a green sheet and a conductor of the firing laminate. Removing the heat shrinkage suppressing layer after integrally firing the paste to obtain a ceramic component. 2. A method for producing a ceramic part by laminating and firing a plurality of green sheets made of a glass-ceramic mixed powder, comprising a conductor powder containing at least Ag powder and an organic vehicle, and having a softening point. A step of preparing a conductor paste containing glass powder of 750 ° C. or more in a range of 0.1 to 10% by weight of the entire conductor powder; and a composite lamination in which a conductor layer made of the conductor paste and the green sheet are laminated. Forming a body, arranging a heat shrinkage-suppressing green sheet on both surfaces or one surface of the composite laminate to obtain a firing laminate, and integrally firing the green sheet and the conductive paste of the firing laminate. And then removing the heat shrinkage suppression layer to obtain a ceramic component. 3. The method for manufacturing a ceramic component according to claim 1, wherein the average particle size of the Ag powder in the conductor paste is 2.9 μm or more. 4. The method for producing a ceramic component according to claim 1, wherein in the firing step, at least a part of the heating rate is at least 200 ° C./h. 5. The glass ceramic used for the green sheet is Al ₂ O ₃ , LnO _x (Ln is La, Ce, Nd,
At least one selected from Sm, Eu, Gd, and Tb, and X is a stoichiometric value determined according to the valence of Ln), MgO and glass as main components. The method for producing a ceramic component according to claim 1.