KR0173233B1 - Manufacturing method of low dielectric rate multi-ceramic circuit board - Google Patents

Abstract

The present invention relates to a method for manufacturing a multilayer ceramic circuit board for mounting LIS devices and general electronic devices, and to form a closed pore of a suitable size and amount inside without adding a polymer pore-forming raw material to provide insulation and moisture resistance. The purpose of the present invention is to manufacture a multilayer ceramic circuit board with excellent refractive index as well as excellent dielectric constant.

The present invention is Pb-Zn-B-based glass powder: 30-70wt% and ceramic powder: 30-90wt% of powder having an average particle diameter of 9-20㎛ and powder of 10-50wt% of an average particle diameter of 3㎛ or less. Mixing -70 wt%; Preparing a slurry having a viscosity of 3000 cps or less by uniformly dispersing the mixed mixture and the organic binder in a solvent solvent; Casting the slurry to form a green sheet; Forming a through-hole at a predetermined position of the green sheet; Dispersing the calcium silicate crystallized glass powder and the organic binder uniformly in a solvent solvent to prepare a slurry having a viscosity of 3000 cps or less, forming a green sheet as described above, and forming a through hole at a predetermined position of the green sheet; Injecting a conductor electrode into each of the through holes formed as described above, and printing the conductor electrode on each sheet surface; Stacking the substrates on which the conductor electrodes are printed as described above and then thermocompressing them; And de-bindering the crimped sheet as described above, and then firing at 750-900 ° C. to produce a free-electric multilayer ceramic circuit board.

Description

Manufacturing method of low dielectric constant multilayer ceramic circuit board

1 is a schematic diagram of a process for manufacturing a multilayer ceramic circuit board in accordance with the present invention.

2 is a schematic cross-sectional view of a multilayer ceramic substrate prepared according to the present invention.

3 is an optical micrograph of the fracture surface of the multilayer ceramic substrate prepared according to the present invention.

4 is a graph showing a change in shrinkage with a change in firing temperature of a substrate.

* Explanation of symbols for main parts of the drawings

1 through hole 2 dense ceramic insulating layer

3: porous ceramic insulation layer 4: conductor electrode

The present invention relates to a method for manufacturing a multilayer ceramic circuit board for mounting a LIS device and a general electronic device, and more particularly, by introducing a suitable closed pores therein and having excellent insulation and moisture resistance and low dielectric constant. The present invention relates to a method for manufacturing a porous multilayer ceramic circuit board.

In recent years, with high integration, miniaturization, and high speed of semiconductor devices, high-density wiring, high-speed transmission of signals, high frequency, high heat dissipation, and the like are required for mounting substrates.

Al ₂ O ₃ substrates, which have been used in the past, must be fired at a high temperature of 1500 ° C., and the limitations of the Al ₂ O ₃ substrates in the high speed transmission of a synchronous signal at high temperatures, the electrical resistance of the conductor wiring, and the miniaturization of the electric wiring pattern are limited. It is revealed. In addition, the recently developed low-temperature calcined multilayer ceramic substrate has low dielectric constant and uses insulating material which is fired at low temperature below 1000 ℃, so it is possible to use Au, Ag, Cu, etc. with low battery resistance as conductor wiring material. I'm satisfied with my back. In high speed transmission of electrical signals, it is very important to reduce the dielectric constant of the substrate in proportion to the square root (√ε) of the dielectric constant of the substrate used. The dielectric constant of the Al ₂ O ₃ substrate is about 10, and recently developed low-temperature fired ceramic substrates are not sufficient in terms of dielectric constant (about 9-4), and there is a need for improvement.

On the other hand, an effective method of reducing the dielectric constant of the substrate is a method of introducing pores into the substrate. That is, since the dielectric constant of air is 1, the dielectric constant of the porous ceramic substrate can be expressed by the following formula (1).

Where ε is the dielectric constant of the porous substrate, εθ is the dielectric constant of the material, and P is the porosity of the substrate. According to Equation (1), the dielectric constant of the substrate decreases as P increases, and introducing pores into the substrate is the most effective for reducing the dielectric constant of the substrate. However, excessive pore introduction into the substrate lowers the strength of the substrate and deteriorates the insulating and moisture resistance characteristics of the substrate when the pores become open pores. Therefore, it is very important to form suitable isolated closed pores in the substrate.

On the other hand, the method of lowering the dielectric constant by forming a suitable isolated closed pores in the substrate may be a method disclosed in Japanese Patent Application Laid-Open No. 2-116196, this method is to form a pore of the polymer to form a closed pore Ingredients must be added

Therefore, the above-described conventional method is difficult to achieve uniform dispersion due to difficulty in uniform mixing due to the density difference of the polymer pore-forming material, and thus it is difficult to obtain uniform distribution of pores.

In addition, the polymer pore-forming material should not be dissolved in an organic binder, so that the selection of the polymer pore-forming material is not only limited, but also a process of preparing the polymer pore-forming material is difficult.

Accordingly, the present inventors have conducted research and experiments to solve the problems of the prior arts described above, and have proposed the present invention based on the results, and the present invention is a Pb-Zn-B system mixed with ceramic powder. After preparing the green sheet using the green sheet and the calcium silicate crystallized organic powder in which the particle size of the glass (Lead-Zinc-Borate Glass) powder is classified into two, and the mixing ratio of the powders classified in the particle size is appropriately prepared, By stacking the two green sheets alternately and firing at low temperature, they form an appropriate size and quantity of closed pores inside without adding polymer pore-forming raw materials to provide excellent insulation and moisture resistance, low dielectric constant, and excellent refractive strength. The purpose is to manufacture a ceramic circuit board.

Hereinafter, the present invention will be described.

The present invention provides a glass powder prepared by preparing a Pb-Zn-B-based glass powder comprising a powder having an average particle diameter of 9-20 μm at a ratio of 10-50 wt% and a powder having an average particle diameter of 3 μm or less at a ratio of 50-90 wt%. Mixing at a rate of 30-70 wt% and mixing ceramic powder therein at a rate of 30-70 wt%; Preparing a slurry having a viscosity of 3000 cps or less by uniformly dispersing the mixed mixture and the organic binder in a solvent solvent; Casting the slurry to form a green sheet; Forming a through-hole at a predetermined position of the green sheet; Uniformly dispersing the calcium silicate crystallized glass powder and the organic binder in a solvent to prepare a slurry having a viscosity of 3000 cps or less, forming a green sheet as described above, and forming a through hole at a predetermined position of the green sheet; Injecting a conductor electrode into each of the through holes formed as described above, and printing the conductor electrode on each sheet surface; Stacking the sheets printed with the conductor electrodes alternately with each other as described above, and then thermally compressing the sheets; And debinding the sheet compacted as described above and firing at 750-900 ° C.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In order to manufacture a multilayer ceramic circuit board according to the present invention, first, a ceramic powder such as Al ₂ O ₃ powder or the like and a Pb-Zn-B-based glass powder are mixed as shown in FIG. 1 schematically showing the manufacturing process of the present invention. .

It is preferable to limit the amount of the ceramic powder added to 30-70wt%, because if the amount is less than 30wt%, not only the strength of the substrate is lowered but also the strain may be deformed. Because.

In addition, the Pb-Zn-B-based glass powder is used with a first powder having an average particle diameter of 9-20 μm and a second powder having an average particle diameter of 3 μm or less, and the amount of the first powder is 10-50 wt%, The amount of the second powder is preferably limited to 50-90wt%, for the following reason.

When the average particle diameter of the first powder is 9 μm or less, the pore size is small, so that the effect of reducing the dielectric constant is small, and when the average particle size is 20 μm or more, the pore size is too large, so that the strength of the substrate is decreased, so that the average particle diameter of the first powder is Is preferably limited to 9-20 μm.

In addition, when the average particle diameter of the second powder is 3 μm or more, small pores are formed after firing to decrease the density to decrease the strength. Therefore, the average particle diameter of the second powder is preferably limited to 3 μm.

When the amount of the first powder is less than 10wt%, the number of large pores decreases, and if the amount of the first powder is more than 50wt%, the strength of the substrate is lowered. Therefore, the amount of the first powder is preferably limited to 10-50wt%. More preferably, it is 30-50 wt%.

In addition, the amount of the second powder is preferably limited to 50-90wt%, more preferably 50-70wt%.

Next, the mixed powder mixed as described above is uniformly dispersed in a solvent solvent with an organic binder to prepare a slurry having a viscosity of 3000 cps or less.

The organic binder is preferably PVA, PVB, acrylic resin, or the like.

When the slurry has a viscosity of 3000 cps or more, it is preferable to limit the viscosity of the slurry to 3000 cps or less since poor flowability during casting of the green sheet causes shape defects and surface defects.

Next, the slurry prepared as described above is cast by a doctor blade film forming method or the like to form a green sheet having a thickness suitable for the application.

Next, a through hole is formed at a predetermined position of the green sheet.

Next, the calcium silicate crystallized glass powder and the organic binder are uniformly dispersed in a solvent to prepare a slurry having a viscosity of 3000 cps or less, then a green sheet is formed as described above, and a through hole is formed at a predetermined position of the green sheet.

Next, a conductor electrode such as Ag is injected into the respective through holes by screen printing or the like, and a conductor electrode such as Ag is printed on the surface of each sheet.

Next, as described above, the respective sheets on which the conductor electrodes are printed are alternately stacked and thermally compressed.

The above-mentioned thermocompression bonding step is carried out in a conventional manner, preferably at a pressure of about 80 psi to about 2000 psi.

Next, the binder sheet is de-bindered as described above, and then fired at 750-900 ° C., thereby producing a multilayer ceramic circuit board.

When the firing temperature is 750 ° C. or lower, the glass does not melt and densify, and coarse processing is not formed. When the firing temperature is 900 ° C. or higher, the temperature of the glass is too high and the viscosity of the liquid glass during firing is too low. Since deformation may occur, the above-mentioned firing temperature is preferably limited to 750-900 ° C.

In the manufacturing method of the present invention, the manufacturing conditions are preferably adjusted to produce a multilayer ceramic circuit board containing 10-40 vol% of isolated pores having a diameter of 5-30 μm.

As can be seen from the above, in the present invention, a green sheet prepared by mixing a Pb-Zn-B-based glass powder and ceramic powder containing large particles of the same component at a constant ratio and a green sheet of calcium silicate crystallized glass powder By alternately laminating and liquid-firing at a temperature above the glass melting point, when large glass particles are heated in a molten state, the molten liquid is sucked by the capillary force of the gap between ceramic particles around the large particles, thereby causing a large Pb-Zn. Closed pores are formed at the position of the -B-based glass particles to lower the dielectric constant of the substrate.

Therefore, the pore size can be controlled by the size of the large glass particles, and the porosity of the entire substrate can be controlled by the content of the large glass particles.

In particular, in the case of the present invention, by stacking the green sheet of the calcium silicate crystallized glass powder of dense structure alternately with the green sheet of the Pb-Zn-B-based glass powder, the refractive strength of the substrate becomes higher.

A schematic diagram of the porous multilayer ceramic circuit board manufactured according to the present invention is shown in FIG.

In FIG. 2, reference numeral 1 denotes a through hole, 2 denotes a dense ceramic insulating layer, 3 denotes a porous ceramic insulating layer, and 4 denotes a conductor electrode.

Hereinafter, the present invention will be described in more detail with reference to Examples.

EXAMPLE

Al ₂ O ₃ ceramic powder and Pb-Zn-B-based glass powder were mixed in a mixing ratio as shown in Table 1 below.

At this time, the Pb-Zn-B-based glass powder was mixed with an average particle diameter of 15μm and an average particle diameter of 2μm in the mixing ratio as shown in Table 1 below.

Next, polyvinyl-butyral was dissolved in a solvent solvent containing dioctyl-phthalate as a main component, uniformly dispersing the mixed powder mixed as described above, and then having a viscosity of 2000 cps. Was prepared.

Next, a green sheet having a thickness of 100 μm was prepared by the doctor blade forming method of the slurry prepared as described above.

Next, a calcium silicate having an average particle diameter of 1.5 µm was dissolved in the organic solvent solvent together with the organic binder to prepare a slurry having a viscosity of 2000 cps, and then a green sheet having a thickness of 100 µm was prepared.

After forming a through hole having a diameter of 150 μm at a predetermined position of each of the green sheets manufactured as described above, Ag conductors were injected by screen printing, and Ag conductor electrodes were printed on the sheet surface.

The green sheets printed as described above were laminated alternately with each other and then pressed by applying a pressure of 2000 psi at about 80 ° C.

The crimped sheet as described above was debindered at 300 ° C., and then calcined at the firing temperature conditions as shown in Table 1 to manufacture a multilayer ceramic circuit board.

The physical properties of the multilayer ceramic circuit board manufactured as described above were investigated, and the results are shown in Table 1 below.

And an optical micrograph of the cross section of the substrate prepared according to Inventive Example (3) in Table 1 is shown in FIG.

On the other hand, with respect to Inventive Example (3) in Table 1, the shrinkage change with the change in the firing temperature was measured, and the results are shown in FIG.

Firing in FIG. 4 was carried out in air, and the rate of temperature increase was 10 ° C. per minute.

As shown in Table 1 above, when the substrate is manufactured under the conditions in accordance with the present invention [Invention Example (1-5), the insulation resistance is 10 Ω or more, dielectric constant is 7.0 or less, and the refractive strength is 1720kgf / cm2 or more, while the physical properties of the substrate are excellent, the refractive strength is 1300 in [Comparative Example (1-3)] outside the conditions of the present invention. It can be seen that the dielectric constant is 8.0 as low as kgf / cm 2 or lower and in the case of Comparative Example (3).

In addition, as shown in FIG. 3, in the case of the substrate manufactured according to the present invention, it can be seen that the porous layer and the dense layer in which the large closed pores are uniformly distributed are stacked.

On the other hand, as shown in Figure 4, it can be seen that the firing temperature of the present invention is preferably about 750-900 ℃.

As described above, in the present invention, the Pb-Zn-B-based glass powder mixed with the ceramic powder is classified into two particle sizes, and the mixing ratio of the powders classified into particle sizes is appropriately adjusted to green sheet and calcium silicate crystallization. By manufacturing green sheet using glass powder, and then laminating the two green sheets alternately and firing at low temperature, insulation and moisture resistance can be formed by forming closed pores of appropriate size and amount inside without adding polymer pore-forming raw materials. It is effective to manufacture multilayer ceramic circuit boards which are excellent and have low dielectric constant as well as excellent refractive strength.

Claims (4)

Prepare a Pb-Zn-B-based glass powder composed of a powder having an average particle diameter of 9-20 μm at a ratio of 10-50 wt%, and a powder having an average particle diameter of 3 μm or less at a ratio of 50-90 wt%. Mixing 70 wt% and mixing ceramic powder at a rate of 30-70 wt%; Preparing a slurry having a viscosity of 3000 cps or less by uniformly dispersing the mixed mixture and the organic binder in a solvent solvent; Casting the slurry to form a green sheet; Forming a through-hole at a predetermined position of the green sheet; Dispersing the calcium silicate crystallized glass powder and the organic binder uniformly in a solvent solvent to prepare a slurry having a viscosity of 3000 cps or less, forming a green sheet as described above, and forming a through hole at a predetermined position of the green sheet; Injecting a conductor electrode into each of the through holes formed as described above, and printing the conductor electrode on each sheet surface; Stacking the sheets printed with the conductor electrodes alternately with each other as described above, and then thermally compressing the sheets; And debindering the crimped sheet as described above and firing at 750-900 ° C. A method of manufacturing a low dielectric constant multilayer ceramic circuit board. The low dielectric constant multilayer ceramic circuit of claim 1, wherein the Pb-Zn-B-based glass powder is composed of 30-50 wt% of powder having an average particle diameter of 9-20 μm and 50-70 wt% of powder having an average particle diameter of 3 μm or less. Method of manufacturing a substrate. The method of manufacturing a low dielectric constant multilayer ceramic circuit board according to claim 1, wherein the ceramic powder is Al ₂ O ₃ powder. The method of manufacturing a low dielectric constant multilayer ceramic circuit board according to any one of claims 1 to 3, wherein the organic binder is one selected from the group consisting of PVA, PVB, and acrylic resin.