JP2003055054A - Method for manufacturing glass ceramic substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass ceramic substrate by which the firing process to decrease pores remaining in a multilayered glass ceramic substrate can be made efficient and a multilayered glass ceramic substrate having specified mechanical strength can be stably obtained. SOLUTION: Wiring conductors are formed on a plurality of ceramic green sheets manufactured by using glass ceramic powder containing borosilicate glass and alumina, and when these sheets are laminated and pressed, an organic solvent is applied to form an organic solvent coating layer (S1) between adjacent ceramic green sheets. The layers are laminated by pressing and the obtained layered body is fired to obtain the multilayered glass ceramic substrate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a glass ceramic substrate.

[0002]

2. Description of the Related Art Conventionally, wiring boards such as LSIs and ICs
Alternatively, a multilayer glass ceramic substrate capable of relatively high-density wiring is often used as a wiring substrate on which semiconductor elements such as discrete components are mounted or various thick film printing elements are formed inside the substrate. In this multi-layer glass ceramic substrate, alumina is used as the ceramic component due to advantages such as strength, and borosilicate glass is used as the glass component because it is close to the thermal expansion coefficient of silicon constituting the semiconductor integrated circuit substrate to be mounted. . In addition, in recent years, high-frequency bands from the microwave band to the millimeter-wave band have been positively adopted for wireless communication such as mobile phones in order to expand the electric wave resources and increase the transmission density. As a component for a wireless communication device used for this, the demand for a wiring board for handling a high frequency signal is explosively increasing.

In such a multilayer wiring glass-ceramic substrate, a plurality of ceramic green sheets having predetermined wiring conductor patterns are formed at 100 ° C. and 200 kg / cm ^2.
It is produced by laminating and press-bonding under a high temperature and high pressure of a certain degree and firing them. However, since the layers are pressure-bonded under high temperature and high pressure, the organic binder contained in the ceramic green sheet cannot be completely burned and removed in the firing step, and remains as pores in the ceramic substrate, which has a drawback of suppressing the mechanical strength. Therefore, attempts have been made to reduce the residual pores by adjusting the firing atmosphere or firing time, and by forming an organic binder from a depolymerizable resin that is easily removed by firing.

Incidentally, as a technique related to this type of technique, for example, Japanese Patent Laid-Open No. 60-254697 and Japanese Patent Laid-Open No. 06-06246.
-268375 etc. are mentioned.

[0005]

DISCLOSURE OF THE INVENTION In the above method,
Controlling the firing atmosphere requires precision and the number of steps, and also requires firing time. Further, firing conditions and the like also change depending on the organic binder material used. These are problems from the viewpoint of productivity. Further, since the pores remaining on the ceramic substrate are reduced and the firing temperature range for obtaining a predetermined mechanical strength is narrow, the yield of the manufactured ceramic substrate becomes unstable, and consequently the productivity is suppressed.

An object of the present invention is to solve the above problems, and in manufacturing a multilayer glass ceramic substrate, the efficiency of the firing process for reducing the remaining pores is improved, and a predetermined mechanical strength is obtained. It is an object of the present invention to provide a manufacturing method capable of stably obtaining a multilayer glass ceramic substrate.

[0007]

Means for Solving the Problems and Actions / Effects The method for manufacturing a glass ceramic substrate of the present invention for solving the above problems comprises a plurality of ceramics composed of a glass ceramic powder containing borosilicate glass and alumina. A multilayer glass ceramic substrate is obtained by forming an organic solvent coating layer between adjacent ceramic green sheets, laminating and pressing the green sheets, and firing the resulting laminated body.

The above-mentioned ceramic green sheet can be obtained by forming a slurry by kneading a glass ceramic powder consisting of a ceramic component and a glass component, an organic binder, a solvent and the like into a sheet by a well-known doctor blade method. . Alumina ceramics, mullite ceramics, aluminum nitride ceramics, silicon nitride ceramics, and silicon carbide ceramics having an alumina content of 98% or more are used as ceramic components because of their small dielectric loss even in strength and high frequency regions. It On the other hand, as the glass component, borosilicate glass is used because it is close to the thermal expansion coefficient of silicon that constitutes the semiconductor integrated circuit substrate. Specifically, borosilicate glass, lead borosilicate, and alkaline borosilicate earth are used. And the like. Further, the glass-ceramic powder made of the above material has a ceramic component of 40 to 60.
By adjusting the content to be the weight%, the simultaneous sintering property with the wiring conductor is improved, which is preferable.

The wiring conductor is formed by a known screen printing method, and the metal material used is silver-based (silver simple substance, silver-metal oxide (manganese, vanadium, bismuth, aluminum, silicon, copper). Etc.), silver-
Glass addition, silver-palladium, silver-platinum, silver-rhodium, etc., gold-based (gold simple substance, gold-metal oxide, gold-palladium, gold-platinum, gold-rhodium etc.), copper-based (copper simple substance, copper) −
Low resistance materials such as metal oxides, copper-palladium, copper-platinum, copper-rhodium, etc. can be used.

Further, as the above organic binder, acrylic resin (eg, polyacrylic acid ester, polymethyl methacrylate), cellulose acetate butyrate, polyethylene, polyvinyl alcohol and polyvinyl butyral, etc., and the solvent are acetone, methyl ethyl ketone, diacetone. , Methyl isobutyl ketone,
It can be composed of benzene, bromochloromethane, ethanol, butanol, propanol, toluene, xylene and the like.

When a plurality of ceramic green sheets having such components are laminated and pressure-bonded by completely curing the organic binder contained therein, a space between adjacent ceramic green sheets is used as a solvent for the organic binder. By forming an organic solvent coating layer containing a functional organic solvent, it is possible to improve the lamination pressure-bonding property between adjacent ceramic green sheets. That is, it is possible to reduce the temperature and pressure for lamination pressure bonding, as compared with the conventional case where the organic solvent coating layer is not provided. Further, by forming the organic solvent coating layer, it is possible to prevent the generation of void defects that are left behind in the obtained laminated body because the air is not completely exhausted during the laminated pressure bonding.

The laminate obtained by the above method is fired,
A sintered body of a multilayer glass ceramic substrate is obtained. Since the mechanical strength of the sintered body depends on the degree of densification thereof, the sintered body obtained by sufficiently removing the organic binder in the firing step. The mechanical strength of can be improved. In the present invention, as described above, it is possible to form the organic solvent coating layer and reduce the pressure and temperature during the production of the laminate, and as a result, the polymerization (complete curing) of the resin constituting the organic binder proceeds. Can be suppressed. Therefore, the organic binder can be decomposed and removed efficiently at a low temperature in the firing step, and not only the mechanical strength of the obtained multilayer glass ceramic substrate can be increased, but also firing for having a predetermined mechanical strength. A wide temperature range can be secured and productivity can be improved.

Next, in the glass-ceramic production method of the present invention, the above-mentioned organic solvent coating layer is characterized by comprising at least one of alcohols, ethers, carboxylic acids, and polyhydric alcohols. The organic solvent forming the organic solvent coating layer needs to be appropriately selected depending on the type of the organic binder. For example, when the organic binder is an acrylic resin, ethyl methyl ketone (ethers) and ethyl acetate (carboxylic acids) work as a solvent. Therefore, one of these or ethyl acetate is mixed with ethyl methyl ketone to form an organic solvent. A coating layer can be formed. Similarly, when the organic binder is polyvinyl butyral, the organic solvent coating layer is formed from butanol (alcohols) or ethyl methyl ketone (ethers) that functions as a solvent. In this way, the organic solvent coating layer can fulfill its function by appropriately selecting the organic solvent forming the organic solvent coating layer according to the change of the organic binder.

Further, an organic solvent miscible with the solvent contained in the ceramic green sheet or an organic solvent containing the same kind is mixed in the above organic solvent coating layer to further improve the pressure-bonding property when the ceramic green sheets are laminated and pressure-bonded. Can be improved. As a result, it becomes possible to more efficiently burn and remove the organic binder in the firing step. If an example of such a combination of an organic binder and a solvent, and an organic solvent coating layer is given,
The organic binder is composed of acrylic resin, and the solvent is composed of ethyl methyl ketone and butanol. For these, ethyl methyl ketone (ethers) and ethyl acetate (carboxylic acid) as the solvent of the organic binder, and ethyl methyl mixed with the solvent An organic solvent coating layer can be formed by mixing a ketone (ether), butanol (alcohol) and butyl carbitol (polyhydric alcohol).

As described above, for the organic coating layer, an organic solvent may be optionally selected for various organic binders and solvents before firing, and the number of steps in the conventional firing step
The time or its accuracy can be significantly improved, which contributes to improvement of productivity and reduction of energy consumption.

Next, in the glass ceramic substrate manufacturing method of the present invention, the firing temperature for sintering the laminated and pressure-bonded ceramic green sheet laminate to obtain the multilayer glass ceramic substrate is the bending of the multilayer glass ceramic substrate. It is characterized in that it is in a temperature range where the strength is at least 200 Mpa. Since many components are mounted on the multilayer glass ceramic substrate, it is necessary to maintain mechanical strength sufficient to withstand loads including them, and the bending strength is about 200 MPa. Since the mechanical strength of the multilayer glass ceramic substrate depends on the density of the sintered body, it is necessary to sufficiently suppress the remaining pores. Further, in the temperature range below the softening temperature of the glass component contained in the ceramic green sheet above the decomposition temperature of the organic binder, it is preferable to effectively burn off the organic binder, and when the temperature is higher than the softening temperature of the glass component, the glass Sintering of the particles is promoted, isolated pores are easily generated inside the ceramic green sheet laminate, and higher temperature treatment is required.
As a result, the firing temperature range for obtaining the mechanical strength is narrowed. However, in the present invention, by forming the organic solvent coating layer, it is possible to lower the decomposition temperature of the organic binder and efficiently burn and remove them, so that the firing temperature range for obtaining a predetermined mechanical strength is lower than that in the conventional manufacturing method. It can be secured and productivity can be improved.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below.
This will be described with reference to the drawings. FIG. 4 shows an appearance of a multilayer glass ceramic substrate (hereinafter, also simply referred to as a substrate) 1 which is an embodiment of the present invention. The surface of the substrate is electrically connected to wiring or circuit patterns formed inside the substrate. A terminal portion 40 for making a connection is formed. FIG. 5 shows the substrate 1
2 schematically shows an internal structure of the glass ceramic layer 50 and the metal wiring layer 30 are alternately laminated, and a semiconductor element 51 is mounted on the surface thereof as required. Each metal wiring layer 30 is a glass ceramic layer 50.
Are electrically connected to each other by a via hole 35 penetrating in the thickness direction. The substrate 1 may be provided with an active element function having high-frequency signal processing capability itself like a high-frequency package in order to function as a high-frequency multilayer ceramic wiring substrate, or may be separately configured. It may be an electronic component for mounting a high-frequency element such as an antenna switch module.

In the substrate 1 of this embodiment, the metal wiring layer 30
Is configured as being accompanied by a ground conductor 56 that functions as a shield portion for noise protection. Ground conductor 5
6 is formed by a method similar to that for the metal wiring layer 30 so as to cover one surface of the glass ceramic layer 50 over substantially the entire surface. Further, in the substrate 1 of this embodiment, various thick film circuit elements such as the capacitor 54, the inductor 53, and the resistor 55 are incorporated in addition to the metal wiring layer 30, but the thick film circuit element is particularly included. It is also possible to form a substrate having only a metal wiring layer. Also,
When the board 1 is a high frequency multilayer ceramic wiring board,
Although the metal wiring layer 30 is sandwiched between the glass ceramic layers 50 and is configured as a so-called strip line,
The high frequency signal in this specification means a signal having a frequency of 800 MHz or higher.

Next, the working process for producing the above-mentioned multilayer glass ceramic substrate will be described. FIG. 1 is a schematic view of the working process. First, glass-ceramic powder, an organic binder, a solvent, etc. are mixed and kneaded, and formed into a sheet by a doctor blade method or the like to produce a ceramic green sheet. Next, a metal powder pattern 131 to be a metal wiring layer (including a pattern of a thick film circuit element when including the element) is formed on the obtained ceramic green sheet by a known screen printing method. , S1, the organic solvent coating layer 160 is formed by coating the entire surface of the surface without the metal wiring layer with the organic solvent (FIG. 6A). In this way, by coating the surface without the metal wiring layer with the organic solvent, it is possible to prevent bleeding of the metal wiring layer, which leads to the occurrence of a short circuit.

When the organic solvent coating layer 160 is completed in this way, the surface side on which the organic solvent coating layer 160 is formed is changed to the one shown in FIG.
As shown in (b), the pattern printing / organic solvent coating process is overlaid on another ceramic green sheet 150, and the pattern printing / organic solvent coating / ceramic green sheet laminating process is repeated. The laminated body 180 shown in 6 (c) is obtained. When the via hole 35 is formed, the via hole is formed in the ceramic green sheet 150 with a drill or the like, and the metal paste is embedded therein. When the laminated body 180 thus obtained is thermocompression bonded and fired, the multilayer glass ceramic substrate 1 having a sectional structure as shown in FIG.
Is obtained.

[0021]

EXAMPLES The results of experiments conducted to confirm the effects of the present invention will be described below.

(Embodiment 1) According to the work process shown in FIG.
A multilayer glass ceramic substrate was manufactured. With respect to 100 parts by weight of glass-ceramic powder, which is 60% by weight of borosilicate glass powder and 40% by weight of alumina powder in the production of ceramic green sheet, 15 parts by weight of an acrylic resin as an organic binder and methyl ethyl ketone and methanol as a solvent are combined. 75 parts by weight and 0.
3 parts by weight were mixed and mixed by a ball mill to prepare a slurry. Next, using the above slurry, a ceramic green sheet having a thickness of 0.25 mm is produced by a doctor blade method, and after forming a through hole, a paste in which Ag-based fine powder is dispersed is embedded and wiring by a known screen printing method. Printing was done. Thereafter, according to the step S1 shown in FIG. 1, an organic solvent was applied between the obtained plurality of ceramic greens to form an organic solvent applied layer, and lamination pressure bonding was performed. Further, the obtained laminated body was cut and fired while continuously raising the temperature from 800 to 1000 ° C. in steps of 30 ° C. to manufacture a multilayer glass ceramic substrate.

Here, the organic solvent forming the organic solvent coating layer is butanol (alcohols), ethyl methyl ketone (ethers), ethyl acetate (carboxylic acids), butyl carbitol (polyhydric alcohols) 4: 4. 1: 2: 3
The weight ratio of

Comparative Example 1 A multilayer glass ceramic substrate was prepared under the same conditions as in Example 1 except that the organic solvent coating layer was not formed.

In Example 1, lamination pressure bonding could be performed by applying a pressure of 30 kg / cm ² for 60 seconds while heating at 40 ° C. On the other hand, in Comparative Example 1 in which there was no organic solvent coating layer. , 200kg / c at 90 ℃
It was necessary to apply a pressure of m ² for 15 minutes. From these results, it was confirmed that the organic solvent coating layer had the effect of reducing the pressure and temperature during lamination pressure bonding.

Next, the residual porosity and bending strength of the sintered bodies obtained at each temperature in Example 1 and Comparative Example 1 were measured. The porosity is obtained by polishing the cross section of the sintered body and scanning electron microscope (S).
When observed by EM) or the like, it was determined from the area ratio of pores on the polished cross section. In consideration of the balance between measurement accuracy and measurement time, the dimensions observed on the polished cross section (when the circumscribed parallel lines are drawn so that the interval is maximum with respect to the hole outer diameter line on the cross section) The value obtained by dividing the total area of pores of 0.5 μm or more by the total area of the observation visual field was adopted as the porosity.

The bending strength was perpendicular to the longitudinal direction of the sintered body adjusted to 3 × 4 × 35 mm, and the bending stress was applied at 25 ° C. at a speed of 0.5 mm / min using a universal testing machine. In addition, the stress-strain curve was measured, and the maximum stress value was read as the bending strength.

FIG. 2 shows the relationship between the obtained firing temperature and the porosity. The horizontal axis represents the firing temperature, and the vertical axis represents the porosity. As is clear from the figure, in Example 1, the softening temperature of the glass component forming the ceramic green sheet (800
In the comparative example 1, the porosity is about 0%, while in Comparative Example 1, the porosity is about 0%.
%. This result shows that in Example 1, the decomposition temperature of the organic binder can be reduced and the removal thereof can be efficiently performed as compared with Comparative Example 1 due to the function of the organic solvent coating layer. Next, the relationship between bending strength and firing temperature is shown in FIG.
The horizontal axis represents firing temperature, and the vertical axis represents bending strength. As can be estimated from the porosity result of FIG.
In the firing temperature range of 00 ° C. or higher, the bending strength becomes 200 MPa or more, and the strength is stabilized. On the other hand, Comparative Example 1 is stabilized only in a narrow firing temperature range of 920 to 1000 ° C.

From the results shown in FIGS. 2 and 3, by forming the organic solvent coating layer, it is possible to effectively burn and remove the organic binder below the softening temperature of the glass component at which the ceramic green sheet laminate begins to sinter. It was confirmed that it was possible to improve the mechanical strength (bending strength) and to secure a wide firing temperature range for obtaining a predetermined mechanical strength.

Example 2 Acrylic resin forming the organic binder of Example 1 was reduced from 15 parts by weight to 10 parts by weight,
By increasing the weight ratio of ethyl methyl ketone (ethers) and ethyl acetate (carboxylic acids) that function as a solvent to the organic binder forming the organic solvent coating layer, butanol (alcohols), ethyl methyl ketone (ethers), ethyl acetate (Carboxylic acids) and butyl carbitol (polyhydric alcohols) were formed in an organic solvent coating layer at a weight ratio of 1: 1: 1: 1. A multilayer glass ceramic substrate was manufactured under the same conditions as in Example 1 except for the above.

The conditions for laminating and pressing the ceramic green sheet laminate were the same as in Example 1. This means that even when the resin component of the organic binder is reduced, the organic solvent coating layer is formed by increasing the amount of the organic solvent that acts as a solvent to increase the lamination pressure-sensitive adhesive property in Example 1.
It shows that you can do the same as. Next, the porosity and bending strength of the sintered body obtained at each temperature in Example 2 were measured under the same conditions as in Example 1. The measurement results are shown in Table 1 together with the results of Example 1.

[0032]

[Table 1]

In the second embodiment, as compared with the first embodiment, 80
It can be seen that the porosity at 0 ° C. is reduced and the bending strength thereof is improved. This indicates that Example 1 and Example 2 were laminated and pressure-bonded under the same conditions, and thus Example 2 in which the weight ratio of the organic binder was small removed the organic binder more efficiently. There is. Further, in order to remove the organic binder, in both Example 1 and Example 2, it is sufficient to continuously raise the firing temperature to 800 to 1000 ° C. in steps of 30 ° C., so that the holding time (for example, the conventional manufacturing method) may be increased. About 2 hours at 600 ° C. (Japanese Patent Laid-Open No. 06-2683)
It was confirmed that the multilayer glass ceramic substrate can be produced in a short time without requiring 75)).

From the above examples and comparative examples, the intended purpose could be achieved by the production method of the present invention. That is, it was confirmed that by forming the organic solvent coating layer, the organic binder can be efficiently removed, and the productivity of the multilayer glass ceramic substrate having a predetermined mechanical strength can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing steps in the present invention.

FIG. 2 is a graph showing the relationship between firing temperature and porosity.

FIG. 3 is a graph showing the relationship between firing temperature and bending strength.

FIG. 4 is a schematic view showing an embodiment of a multilayer glass ceramic substrate.

FIG. 5 is a schematic diagram following FIG. 4.

FIG. 6 is a schematic diagram showing a process of forming an organic solvent coating layer.

[Explanation of symbols]

1 Multi-layer glass ceramic substrate 150 ceramic green sheets 160 Organic solvent coating layer 180 laminate

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G030 AA03 AA04 AA07 AA08 AA35                       AA36 AA37 BA12 CA08 GA03                       GA04 GA14 GA17 GA19 GA20                       GA27                 5E346 AA12 AA15 AA38 BB01 CC18                       CC32 CC38 CC39 CC51 DD02                       DD34 EE24 EE26 GG07 GG09                       HH11 HH33

Claims (3)

[Claims] 1. A method of manufacturing a glass ceramic substrate, comprising: a plurality of ceramic green sheets made of glass ceramic powder containing borosilicate glass and alumina; and an organic solvent coating layer between adjacent ceramic green sheets. A method for producing a glass-ceramic substrate, comprising: forming and laminating-bonding, and firing the obtained laminated body to obtain a multilayer glass-ceramic substrate. 2. The organic solvent coating layer comprises alcohols,
The method for producing a glass ceramic substrate according to claim 1, wherein the method comprises at least one of ethers, carboxylic acids, and polyhydric alcohols. 3. The method for manufacturing a glass ceramic substrate according to claim 1, wherein the firing temperature is in a temperature range in which the bending strength of the multilayer glass ceramic substrate is at least 200 MPa.