JPH05229875A - Production of ceramic substrate - Google Patents

Abstract

PURPOSE:To provide the subject production method so designed that punched ceramic sheets are stacked through fine sand layers, and in calcining the resultant laminate, the fine sand is made to adhere to the sheets using a dispersion, thereby preventing the final substrate from declining in its quality in the calcining process, improving workability and automating the work. CONSTITUTION:Formed ceramic green sheets are punched and made into individual sheets each with a slit. These sheets are then stocked in an adsorption carrying device 20 and activated at all times with a press 22. The sheets are then made to adsorb onto an arm 21 one by one, put on a conveyor 10, moved in the arrow direction, and brought into a spray zone A, where the sheets 1 are sprayed and coated with a dispersion 7 for fine sand from the nozzle 30 of a spraying machine. The dispersion 7 is an alumina dispersion prepared by incorporating an aqueous solution of methyl cellulose (binder) with alumina powder for the fine sand. The sheets 1 coated with the dispersion 7 are then heated by a heater 40 and dried in a drying zone B where the fine sand is made to uniformly adhere, in the form of layer 8, to the surface of the sheets 1; the resulting sheets 1 are mutually laminated and calcined.

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 substrate used for electronic parts.

[0002]

2. Description of the Related Art Ceramic substrates used for electronic parts such as chip resistors and chip capacitors are manufactured as follows. First, a slit for breaking is formed vertically and horizontally by pressing, etc. on a green sheet made of ceramic formed into a width and a thickness necessary to obtain a ceramic substrate of a predetermined size, and the portion where the slit is formed is a sheet. It is punched from the sheet and made into an individual sheet with slits. The individual sheets are further fired and then broken through the slits to form individual ceramic substrates.

Looking at the firing process in the manufacturing process in detail, the firing is performed by stacking a plurality of green sheets, placing the sheet laminate on a firing sheath plate, and then stacking the sheath plates in multiple stages. Is common. In that case, in order to prevent the sheets from fusing together during firing, the sand 2 (see FIG. 2) or the spread paper 3 (see FIG. 4) is interposed between the green sheets 1. In the case of grain sand, as shown in FIG. 3, alumina powder 2 for grain sand is sprinkled with a sieve 50 or the like on a plurality of green sheets 1 arranged. Further, the backing paper 3 contains alumina powder therein and is sandwiched between the green sheets 1.

Sheet laminate 5 thus obtained
5 is placed on the firing sheath plate 60 as shown in FIG. 5, and the firing is performed after stacking the sheath plates 60 in multiple stages.

[0005]

Among the above-mentioned stacking methods, the stacking method with the interposition of the interlocking sand simply involves spraying the alumina powder 2 for the interlocking sand on the green sheet 1, so that the alumina on the green sheet 1 is simply spread. The powder 2 is likely to move and become non-uniformly distributed. If firing is performed in this state, the substrates may adhere to each other, or the substrates may be warped or deformed.

Further, since the alumina powder 2 is only placed on the green sheet 1, the sheet laminate 5 is in an unstable state, and the sheet 1 is likely to be displaced or collapsed.
For this reason, it is necessary to handle the laminate 5 carefully, and not only the work efficiency such as transportation is poor, but also it is difficult to automate the processes from stacking the green sheets to firing the laminate.

Therefore, an object of the present invention is to provide a method for manufacturing a ceramic substrate which prevents deterioration of the substrate quality during firing, improves workability and automates a series of operations.

[0008]

In order to achieve the above object, the method of manufacturing a ceramic substrate according to the present invention comprises stacking ceramic sheets punched from a molded sheet with sand grains interposed between the sheets. In the method for manufacturing a ceramic substrate for firing a sheet laminate, the sand is obtained by applying a dispersion liquid prepared by using a solute for sand and an aqueous binder dispersion solvent onto a sheet, and drying and adhering this. It is characterized by

In the production method of the present invention, the grain sand interposed between the sheets is not a mere alumina powder as in the prior art, but a dispersion prepared by using a solute for grain sand (mainly alumina powder) and an aqueous binder dispersion solvent. Since the solution is applied and dried, the dried sand adheres to the sheet after drying, and the thickness of the sand layer is uniform. As a result, workability such as transportation is improved, and adhesion between the substrates and warpage of the substrates do not occur during firing.

Further, by adding a colorant to the dispersion, the sand particles adhering to the sheet are colored, and it becomes possible to confirm the adhering condition of the sand particles by the color, and based on this, a more uniform distribution can be obtained. A thick grain of sand can be formed. Alumina powder is generally used as the solute for grain sand used in the dispersion in the present invention, and methyl cellulose, polyvinyl alcohol (PVA), or the like is used as the aqueous binder dispersion solvent.

[0011]

EXAMPLES A method for manufacturing a ceramic substrate of the present invention will be described below based on examples. Before describing the overall manufacturing process, FIG. 1 shows an apparatus used for forming grain sand, which is a feature of the present invention, and a grain formation step using the apparatus. This apparatus includes an adsorption / conveyance machine 20 for placing the slitting green sheet 1 on the conveyance conveyor 10, and
The sheet 1 transferred by the transport conveyor 10 is provided with a sprayer (not shown) for spraying the dispersion for grain sand and a dryer (not shown) for drying the dispersion on the sheet 1. The sprayer and the dryer are respectively installed in the spraying zone A and the drying zone B which are set in order from the upstream side of the transport conveyor 10.

Next, a specific manufacturing process will be described, but the process up to the formation of grain sand may be carried out in the conventional manner. That is, as described above, the slits for breaking are formed in the vertical and horizontal directions by pressing or the like on the green sheet made of ceramic formed into the width and thickness necessary to obtain the ceramic substrate of the predetermined size. The cut part is punched out from the sheet to make an individual sheet with slits.
The size of this individual sheet is, for example, a square having a side of about 75 mm and a thickness of about 0.6 mm.

The green sheet 1 thus obtained is stored in the suction transporter 20 as shown in the drawing. Seat 1 is arm 2
1 is adsorbed one by one and is sequentially placed on the conveyor 10. The conveyor 10 is moved in the direction of the arrow by the roller 11, and the sheet 1 passes through the spray zone A and the dry zone B in order. The sheet 1 in the suction conveyance device 20 is always urged upward by the pressing tool 22 so that the arm 1 can easily suck the sheet 1 even when the remaining amount of the sheet 1 is small.

In the spray zone A, the sand dispersion liquid 7 is jetted toward the sheet 1 from the nozzle 30 of the sprayer. In the dispersion liquid 7 used here, alumina powder commercially available for grain sand is used as the solute, and methyl cellulose is used as the aqueous binder dispersion solvent. In the preparation of the dispersion liquid 7, first, methyl cellulose as a binder is dissolved in water to prepare an aqueous solution of 0.5 to 5 wt%, to which 5 to 15 parts by weight of the alumina powder for grain sand is added and stirred and mixed. , To obtain an alumina dispersion. At the time of preparation, by adding 1 to 2% of a polycarboxylic acid salt or the like as a dispersion accelerator, the alumina powder can be effectively dispersed. When coloring the dispersion, for example, commercially available rhodamine is used as a coloring agent in an amount of 1 to 2
% May be added.

The sheet 1 thus dispersed with the alumina dispersion 7 reaches the drying zone B and is heated by, for example, the heater 40 of the dryer. As a result, the dispersion liquid 7
The water content therein evaporates, the dispersion liquid 7 dries, and the sheet 1
A sheet 1 having a grain 8 is obtained by depositing as a grain layer on the surface of. The grain sand 8 has an appropriate strength due to the binder in the grain sand. The temperature of the dry zone B is about 100 ° C.
Then, the time for the sheet 1 to pass through the dry zone B is about 1 minute.

After that, a plurality of green sheets with grain sand are stacked, the sheet laminated body is stacked on a firing sheath plate, and then the sheath plates are stacked in multiple stages, and then the multi-stage sheath plates are conveyed to the firing process. To do. The firing is performed, for example, in a tunnel furnace, and the green sheet is sintered by firing. Individual ceramic substrates are obtained by separating the sheet from the slits into individual sheets after firing.

Here, since the grain sand having an appropriate strength is attached on the sheet, when the sheet laminated body is conveyed from the grain forming step to the firing step, the laminated body is tilted or the sheets are rubbed against each other. With such a degree, the sand is not peeled off, and the suction conveyance is possible. Further, if the dispersion liquid is colored, it is possible to easily confirm the spraying state of the alumina dispersion liquid 7, especially in the spray zone A, and it is possible to detect a spraying abnormality at an early stage.

[0018]

As described above, according to the method for producing a ceramic substrate of the present invention, a dispersion liquid prepared by using a solute for grain sand and an aqueous binder dispersion solvent is applied onto a sheet and dried and attached. The following effects are achieved because the sand is used as sand. (1) Since the grain sand has a uniform thickness on the sheet,
The fusion between the sheets during firing and the warpage and deformation of the substrate do not occur, and the yield and quality are improved. (2) Since the stability of the sheet laminate is improved, the handleability of the sheet laminate is improved, the workability is improved, and the productivity is increased. (3) Since the stability of the sheet laminated body is improved, the conveyance of the sheet laminated body can be automated.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus used in a grain forming step in the manufacturing method of the present invention.

FIG. 2 is a side view of one form of a conventional sheet laminate.

FIG. 3 is an explanatory view showing how to put grain sand on a sheet.

FIG. 4 is a side view of another form of the conventional sheet laminated body.

FIG. 5 is a side view showing a state where a plurality of firing sheath plates on which the sheet laminate is placed are stacked.

[Explanation of symbols]

 1 Green sheet 5 Sheet laminate 7 Alumina dispersion 8th sand

Claims (3)

[Claims] 1. Sheets made of ceramics punched out from molded sheets are stacked with interposing sand between the sheets,
In the method for manufacturing a ceramic substrate for firing this sheet laminate, in the sand grain, a dispersion liquid prepared by using a solute for sand grains and an aqueous binder dispersion solvent is applied onto a sheet and dried.
A method for manufacturing a ceramic substrate, characterized in that it is attached. 2. The method for producing a ceramic substrate according to claim 1, wherein the solute for grain sand is alumina powder. 3. The method for producing a ceramic substrate according to claim 1, wherein a colorant is added to the dispersion liquid.