JP2002265281A - Setter for firing electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a setter for firing an electronic part, which is lightweight, excellent in air permeability, capable of easily and rapidly carrying out a de- binder treatment from a green sheet and has excellent strength without causing a damage due to the heat cycle. SOLUTION: The setter 1 is composed of a porous ceramic plate 2 formed by bonding a ceramic fiber and a ceramic particle with each other and having 1.21-1.60 g/cm<3> bulk density, and air permeable holes 3 having 0.2-5 mm, preferably 0.5-2 mm diameter are perforated to penetrate from the front surface to the back surface at an interval of 3-10 mm. The distance L from the center of the air permeable hole 3 to the outer periphery of the porous ceramic plate 2 is preferably >=10 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic setter used for firing electronic components such as a low-temperature fired ceramic multilayer substrate. And a method for manufacturing the same.

[0002]

2. Description of the Related Art Recent advances in electronic devices have been remarkable, and in particular, electronic circuits have been moving toward higher densities, higher speeds, and higher frequencies.
It is rapidly progressing in fields such as measuring instruments. In response to such advances in electronic circuits, mounting substrates are increasingly required to have a low dielectric constant, a low coefficient of thermal expansion, a multilayer structure, a built-in LCR, a low resistance, a low cost, and the like.

As a mounting substrate satisfying these requirements, a low-temperature fired ceramic multilayer substrate has been developed. This ceramic multilayer substrate prints a conductive paste on the surface of a green sheet mainly composed of Al ₂ O ₃ or a glass component,
After laminating several sheets, they are placed on a ceramic setter, the binder is removed from the organic binder in the green sheet, and then the green sheet and the conductive paste are simultaneously fired.

Generally, the green sheet for a low-temperature fired ceramic multilayer substrate contains a glassy component of 40 to 60% by weight in addition to Al ₂ O ₃ , and uses Ag or Cu as a conductive paste. , Firing temperature is 90
It is about 0 to 1100 ° C. As the setter for firing, a dense setter made of alumina or mullite, which is manufactured by sintering a ceramic powder, has been conventionally used.

However, ceramic setters conventionally used for firing electronic components such as green sheets are dense sintered bodies. Binder processing has become very difficult. In addition, since the green sheet contains a large amount of glass components and the debinding temperature and the softening temperature of the glass are close to each other, if the organic binder in the green sheet cannot be quickly discharged from the setter side, the substrate such as a fired substrate may be used. There were problems such as cracks or discoloration of the product.

[0006]

Recently, in order to quickly discharge an organic binder in a green sheet, a porous ceramic plate is used as a setter in some cases. However, since the conventional porous ceramic plate is formed by bonding ceramic fibers and ceramic particles to each other with an inorganic binder such as alumina sol or silica sol, it is difficult to obtain a desired air permeability as a setter.

That is, in order to obtain a permeability of about 0.01 cm ² or more, which is desirable as a setter, it is necessary to reduce the bulk density of the porous ceramic plate to increase the porosity. , There is a drawback that it cannot be used. In particular, when the thickness of the setter was reduced, it was impossible to obtain a setter having both sufficient air permeability and strength.

Further, since the conventional setter made of a porous ceramic plate is mainly made of alumina or mullite, its coefficient of thermal expansion at 1000 ° C. is 6 to 8 × 10 ⁻⁶ / K.
There is a drawback that cracks and cracks easily occur due to a thermal cycle in a firing step of the electronic component.

The present invention has been made in view of such a conventional situation,
An electronic component firing setter that is lightweight, has excellent air permeability, can easily and quickly perform a binder removal treatment from a green sheet, does not suffer damage due to thermal cycling, and has excellent strength, and a method of manufacturing the same. The purpose is to provide.

[0010]

In order to achieve the above object, the present invention provides a setter for sintering electronic parts, which comprises a ceramic fiber and ceramic particles having a bulk density of 1.21 to 1.60 g / cm. ³ is characterized in that vent holes having a diameter of 0.2 to 5 mm are formed at an interval of 3 to 10 mm through the front and back surfaces of the porous ceramic plate. Further, it is preferable that the distance between the center of the ventilation hole and the outer peripheral edge of the porous ceramic plate is 10 mm or more.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, for example, a setter 1 of the present invention comprises a porous ceramic plate 2 containing ceramic fibers and ceramic particles and having a bulk density of 1.21 to 1.60 g / cm ^3. A large number of ventilation holes 3 are formed so as to penetrate from the front surface to the back surface. In particular, by setting the bulk density of the porous ceramic plate 1 in the range of 1.21 to 1.60 g / cm ³ , the mechanical strength is enhanced, and at the same time, the ceramic plate 2 is provided with a large number of ventilation holes 3 to achieve green. It has air permeability suitable for debinding of the sheet.

The porous ceramic plate 2 serving as the base of the setter 1 is mainly composed of ceramic fibers and ceramic particles, and has a bulk density in the range of 1.21 to 1.60 g / cm ³ . If the bulk density is less than 1.21 g / cm ³ , sufficient strength cannot be obtained, and when a large number of air holes 3 are formed, the air holes 3 are easily damaged. Conversely, if the bulk density exceeds 1.60 g / cm ³ , the air permeability of the ceramic plate 2 itself decreases, so that it is difficult to perform a good debinding treatment even if a large number of air holes 3 are formed. . In addition, the bulk density of the porous ceramic plate 2 can be adjusted by the pressing pressure at the time of forming the compact, the length of the ceramic fiber used, the blending of the ceramic particles, and the like.

The air holes 3 penetrating the front and back surfaces of the porous ceramic plate 2 have a diameter of 0.2 to 5 mm, preferably 0.5 to 5 mm.
The distance between the ventilation holes 3 is 3 to 10 mm. When the diameter of the air holes 3 is less than 0.2 mm or the interval exceeds 10 mm, the debinding property of the setter 1 decreases. When the diameter of the ventilation hole 3 exceeds 5 mm or the interval is less than 3 mm, the strength of the setter 1 is reduced and the setter 1 is easily broken.

Further, with respect to the large number of air holes 3 provided in the porous ceramic plate 2, it is preferable that the distance L between the center of each air hole 3 and the outer peripheral edge of the porous ceramic plate 2 is at least 10 mm, More preferably, they are separated by 15 to 20 mm. The distance L between the center of each vent hole 3 located at the outermost periphery and the outer peripheral edge of the porous ceramic plate 2 is 10 mm.
If it is less than the above, the outer peripheral portion of the setter 1 is easily damaged during handling. In addition, the formation of the vent hole in the porous ceramic plate can be performed by using a drill or a laser.

The setter 1 of the present invention comprising a porous ceramic plate 2 having a large number of ventilation holes 3 has a bending strength of 5M.
It is preferably Pa or more. If the bending strength of the setter 1 is less than 5 MPa, the setter 1 is easily damaged by handling or debinding, and cannot withstand repeated use several times or more. Further, by having a bending strength of 5 MPa or more, the thickness of the setter 1 can be reduced, and more specifically, the setter 1 having a thickness of about 1 to 4 mm can be manufactured.

Further, the porous ceramic plate constituting the setter has a structure in which the ceramic fibers and the ceramic particles are mutually
That is, the ceramic fibers are connected to each other, the ceramic particles are connected to each other, and the ceramic fiber and the ceramic particles are bonded by a crystal phase mainly composed of a cordierite phase. The cordierite phase is formed by the reaction of ceramic fibers, mullite powder, magnesium hydroxide powder and / or magnesium carbonate powder, as described below.

Since the cordierite phase has a small coefficient of thermal expansion, the coefficient of thermal expansion of the ceramic plate at 1000 ° C. is 2.
5 to 4.5 × 10 ⁻⁶ / K. Since this coefficient of thermal expansion is remarkably reduced to about half or less as compared with the conventional alumina or mullite setter, the setter does not suffer damage such as cracks and cracks even in severe thermal cycles. Further, since the cordierite phase shrinks at the time of formation, large pores are easily formed between ceramic fibers and ceramic particles. For this reason, ceramic plates are
It has excellent air permeability while having a bulk density of 1.60 g / cm ³ .

Next, a typical production method of the setter of the present invention will be described. For example, ceramic fibers containing alumina are dispersed by stirring in water, and then mullite powder and magnesium hydroxide (Mg (OH) ₂ ) are used as ceramic powder.
The powder and / or magnesium carbonate (MgCO ₃ ) powder is added and stirred, and a silica sol as a temporary binder is further added and stirred to form a slurry. When preparing the slurry, the mixing ratio of each component is adjusted so that the ceramic fiber is 10 to 5 times.
0% by weight, magnesium hydroxide powder and / or magnesium carbonate powder is 3 to 8% by weight in terms of oxide (MgO),
It is preferable that the silica sol be 2 to 10% by weight and the balance of mullite powder.

A coagulant such as an organic polymer is added to the slurry to cause coagulation, and suction is applied while applying pressure to form the slurry. The bulk density of the obtained porous ceramic plate can be easily changed by the pressure applied at this time. After drying the obtained compact, 1300 to 14
Bake at 00 ° C. By this firing, the Mg (OH) ₂ particles and / or MgCO ₃ particles as the magnesium source are changed into magnesium oxide (MgO), and at the same time, the alumina, silica, and mullite particles in the ceramic fiber, and these are temporarily bonded. Reacts with the silica sol to form a crystalline phase mainly composed of a cordierite phase. In addition, the sintering temperature was set at 13 for the formation of the cordierite phase.
The temperature must be at least 00 ° C., but if it exceeds 1400 ° C., it will be close to the melting point of cordierite, so a firing temperature of 1400 ° C. or less is preferred.

The ceramic fiber and the ceramic particles are bonded to each other by the crystal phase mainly composed of the cordierite phase, and a porous ceramic plate having a bulk density of 1.21 to 1.60 g / cm ³ is obtained. Thereafter, a large number of vent holes having a diameter of 0.2 to 5 mm are regularly formed through the front and back surfaces of the porous ceramic plate at intervals of 3 to 10 mm, whereby the electronic component firing setter of the present invention is provided. Is obtained. In addition, the means for perforating the ventilation holes in the ceramic plate is not particularly limited, and can be carried out by using a normal drill, a laser, or the like. When the diameter of the air hole is large, it is possible to form the air hole at the same time when the molded body is formed.

As the ceramic fiber containing alumina,
Alumina fibers having a high alumina content may be used, but in order to reduce costs, it is preferable to use aluminosilicate fibers or mullite fibers. Among them,
A fiber containing alumina and silica in a weight ratio of about 1: 1;
For example, Isowool (trade name) manufactured by Isolite Industry Co., Ltd.
Etc. can be suitably used.

As the ceramic powder to be used, mullite powder and Mg (OH) ₂ powder and / or MgCO ₃ powder are used in combination. These ceramic powders are necessary for forming a crystal phase mainly composed of a cordierite phase. In particular,
In order to promote the formation of the cordierite phase, it is preferable to use a ceramic powder having a small particle size. Specifically, the average particle diameter of the Mg (OH) ₂ powder and the MgCO ₃ powder is preferably 10 μm or less, and the average particle diameter of the mullite powder is preferably 30 μm or less.

The thus-obtained setter of the present invention is lightweight, excellent in air permeability, has sufficient strength and heat resistance,
It can be used up to a high temperature of 1200 ° C. in the air, and can easily and quickly remove the binder from the green sheet. In addition, since the coefficient of thermal expansion is extremely small at 2.5 to 4.5 × 10 ⁻⁶ / K, the spalling resistance is excellent, and damages such as cracks and breakage occur even in a heat cycle of heating and quenching. Therefore, the firing of electronic components such as green sheets can be stably performed.

Further, in the setter of the present invention, a thin coating layer of air-permeable alumina or zirconia is provided on the surface of the setter, so that the reaction with the glass component in the green sheet and the conductive paste provided on the green sheet is completely completed. This prevents the particles from falling off the surface of the setter during use. Examples of the method for forming the coating layer include plasma coating, dipping, and spray coating, and a method that does not significantly affect the air permeability of the setter is preferable.The weight of the coating layer is the same as that described above for the weight of the setter. It is desirably 10% by weight or less based on the weight.

Preferred methods for forming the coating phase include:
Al with an average particle size of 0.5 μm or less₂O ₃Powder or ZrO₂
A suspension of the powder is made and this is
Spraying or dipping on the surface
After firing, it is fired at 1100 to 1250 ° C. Use
If the average particle size of the powder exceeds 0.5 μm,
This is not preferable because it blocks pores on the surface. More preferred method and
And Al₂O₃Or ZrO₂Spray or sol
Coated by dipping and dried at 100 ℃ or more
Then, there is a method of firing at the same temperature as above. this
The method uses finer particles, so when drying
Moves to the surface side of the setter and forms an extremely thin coating layer.
Can be formed.

[0026]

EXAMPLE In 20 liters of water, ICI alumina fiber (Al ₂ O ₃ : 97% by weight, S
iO ₂ : 3% by weight, average fiber length 1 mm, average fiber diameter 3.
1 μm) and 15% by weight of Isowool (Al ₂ O ₃ : 47% by weight, SiO ₂ : 53% by weight, average fiber length 1 mm, average fiber diameter 2.8 μm) manufactured by Isolite Industry Co., Ltd. Was. Next, a mullite powder 60 wt% of an average particle size of 5μm, Mg (OH) ₂ powder having an average particle size of 10μm was added 6 wt% in terms of MgO, further SiO ₂ content 40
3% by weight (solids) of silica sol was added and stirred for a few minutes to form a slurry.

An aqueous solution of an organic polymer flocculant was added to this slurry to cause coagulation, and the resulting slurry was pressed and formed into a plate having a length of 200 mm × 200 mm × thickness of 3 mm, and the press pressure was changed for each sample. The obtained plate-shaped molded body was dried at 120 ° C. and then fired at 1350 ° C. for 3 hours to produce porous ceramic plates. When the crystalline phase of the porous ceramic plate of each sample was analyzed, it was found that the porous ceramic plate was almost composed of a mullite phase and a cordierite phase.

In this example, the bulk density of the porous ceramic plate of each sample was changed as shown in Table 1 below by changing the pressing pressure during molding. Next, a setter was manufactured by piercing holes in the ceramic plate of each sample at a diameter and an interval shown in Table 1 using a drill. The bending strength of each setter of each sample was measured, and the results are shown in Table 1. In addition, a green sheet of a low-temperature fired ceramic multilayer substrate is actually placed on the surface of the setter of each sample, and fired at 950 ° C. for 50 minutes.
The number of times the setter can be used and the debinding property were evaluated, and the results are shown in Table 1.

[0029]

[Table 1]

As can be seen from Table 1, Samples 1 to 4 of the present invention
In addition, there is no defective binder removal, it can be used more than 50 times repeatedly, and even if heating and quenching at 950 ° C. are repeated during firing, no damage such as cracks or cracks is generated in the setter, and the green sheet And almost no reaction with the conductive paste occurred. On the other hand, the sample 5 of the comparative example was insufficient in strength due to low bulk density, and the setter was broken by firing 30 times. In addition, Sample 6 of Comparative Example has a small vent hole and Sample 7 has too large bulk density, and thus both have poor binder removal properties. Further, Sample 8 had too large a vent, so that the strength was reduced and cracks occurred.

[0031]

According to the present invention, it is lightweight and excellent in air permeability,
An electronic component firing setter that can be used up to 1200 ° C., is free from cracks and cracks due to thermal cycling, is excellent in strength, is not damaged, and can be reduced in thickness, and a method of manufacturing the same. Can be provided.

Accordingly, by using the setter of the present invention, the binder can be easily and quickly removed from the green sheet, and the setter is not damaged even if it is repeatedly used. Electronic components such as green sheets can be fired efficiently and stably with a high yield.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a specific example of an electronic component firing setter according to the present invention.

[Explanation of symbols]

 1 setter 2 ceramic plate 3 vent

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoichi Kazuya 1-1 1-1 Yamashitacho, Kokubu-shi, Kagoshima F-term (reference) 4K055 AA08 HA02 HA14

Claims (2)

[Claims] 1. A porous ceramic plate having a bulk density of 1.21 to 1.60 g / cm ³ in which ceramic fibers and ceramic particles are bonded to each other, penetrating the front and back surfaces and having a diameter of 0.2 to 5 mm. An electronic component firing setter, wherein ventilation holes are formed at intervals of 3 to 10 mm. 2. The electronic component firing setter according to claim 12, wherein the distance between the center of the vent hole and the outer peripheral edge of the porous ceramic plate is at least 10 mm.