JPH0618127B2 - Method for manufacturing ceramic substrate for electronic component - Google Patents

Description

Detailed Description of the Invention

[Industrial applications]

The present invention relates to a method for manufacturing a ceramic substrate for electronic components such as chip resistors.

[Prior art]

Small electronic components such as chip resistors are flat rectangular ceramic substrates with unit component regions in a plurality of columns and a plurality of rows divided by lattice slits consisting of vertical slits and horizontal slits with a predetermined depth. After forming an element structure such as an electrode film and a resistance film by the thick film printing method on the surface of the device to make a large number of electronic components on one ceramic substrate at a time, A manufacturing method is adopted in which each unit electronic component is obtained by dividing by. The above-mentioned ceramic substrate is generally manufactured as follows. A raw material consisting of fine alumina powder and a sintering aid, a solvent, and a binder material are mixed to form a suspension, and the solvent is removed by drying to remove the solvent to form a semi-dry belt sheet with a predetermined thickness. It is molded, cut into a predetermined size and shape, and at this point, the above-mentioned lattice slits are press-formed on the surface. The substrate intermediate product thus obtained is then sintered and solidified in a sintering furnace.

[Problems to be Solved by the Invention]

Since the above green sheet before cutting and slit formation is in a relatively soft state because it is convenient to perform the above cutting and slit formation, this green sheet is deformed during handling up to the firing step, It was a cause of defective products. In other words, because of the flexibility of the green sheet after cut molding and slit molding, due to its flexibility, it is unavoidable to perform careful and complete removal of the cutting powder that is inevitably generated during cutting by hand, and at this time the green sheet -Sheets are often deformed by bending and tearing from the slits or uneven elongation. The above-mentioned deformation during handling of the green sheet is hard to detect by visual inspection, and in the manufacturing process of chip-type electronic parts aiming at downsizing of parts in the first place, especially in the process of forming elements by the precision thick film printing method. There is a problem that it becomes a fatal defect and becomes apparent. Therefore, an object of the present invention is to provide a ceramic for electronic parts, which is less likely to be deformed during the handling of the green sheet after cut molding and slit formation, and which is capable of automatically removing the chips generated during cut molding. A method of manufacturing a substrate is provided.

[Means for Solving the Problems]

In order to solve the above problems, the method of the present invention takes the following technical means. That is, the method for producing a ceramic substrate for electronic parts of the present invention comprises a step of producing a strip-shaped green sheet having a flexibility suitable for cut molding and slit molding from a liquid material containing a raw material, a solvent and a binder, A step of cutting and forming an intermediate product of a predetermined shape from a plate-like green sheet and forming a grid-like slit on the surface thereof to obtain a semi-finished primary substrate. The semi-finished primary substrate is produced at 120 ° C to 180 ° C. Heating and drying in air for 5 to 20 hours to obtain a secondary substrate semi-finished product having a lower flexibility than the primary substrate semi-finished product; and baking and solidifying the secondary substrate semi-finished product in a heating furnace. Characterize.

[Action]

The binder agent that gives flexibility to the semi-finished primary substrate is
As a result of being partially removed in the intermediate drying step, which is a characteristic step of the method of the present invention, the semi-finished secondary substrate product has an appropriate hardness that is not inconvenient for automatic handling.

【The invention's effect】

Therefore, according to the method for manufacturing a ceramic substrate for an electronic component of the present invention, the secondary substrate semi-flexible having a reduced flexibility from the cutting of the green sheet into a predetermined shape and the formation of the slit to the firing step. Since the product intervenes,
Even when manually removing the chips produced during cut molding, the shape retention of the semi-finished secondary substrate does not cause it to deform unintentionally. Occurrence can be significantly reduced. In addition, since it is possible to give shape retention to withstand vacuum adsorption or mechanical chucking to the secondary substrate semi-finished product, the above chips are automatically removed, and the secondary substrate semi-finished product to the sintering furnace is also removed. It is possible to automatically carry in. As a result, the steps from the forming of the green sheet to the firing of the substrate can be made continuous, and the effect of significantly improving the production efficiency of the ceramic substrate can be expected.

[Explanation of Examples]

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 shows a process of forming a strip-shaped green sheet. About 95% of alumina fine powder, about 4% of baking aid consisting of silica and calcium oxide, and a substrate material consisting of a mixture of some additives and a binder agent consisting of polyvinyl butyral and dibutyl phthalate are dispersed in a suitable solvent. The relatively viscous suspension 1, which is formed as described above, travels at a constant speed according to the rotation of the roller 2 through a gap between the roller 2 and a doctor blade 4 facing the roller with an edge at a predetermined interval. While being carried on the resin film 3, the resin film 3 is continuously drawn out. Behind the doctor blade 4, a liquid reservoir 6 is formed by the doctor blade 4, a part of the peripheral surface of the roller 2 and a wall 5 contacting the peripheral surface of the roller 2, and the liquid reservoir 6 is formed. The suspension 1 is continuously supplied to 6. The roller 2 and the doctor blade 4 have a constant lateral length, so that the suspension drawn onto the running resin film 3 has a strip shape having a predetermined thickness and a predetermined width. The resin film 3 moves as it is in an atmosphere of about 100 ° C., during which the solvent in the suspension is vaporized and dissipated, and this suspension has a cake-like band-like solid substance that has some flexibility. Becomes This band-shaped solid is a resin film 3
The peeling roller 7 peels off the resin film 3
, And subsequently by a plurality of rotary slitters 8,
As shown in FIG. 2, it is divided into a plurality of strips having a width corresponding to the dimensions of the target ceramic substrate. And each obi is
It is rolled up. The strip-shaped green sheet 9 thus formed is cut into a rectangular shape, and a lattice-shaped slit 10 having vertical slits 10a and horizontal slits 10b having a predetermined depth is press-molded on the surface of the strip-shaped green sheet 9, as shown in FIG. A primary substrate semi-finished product 11 as shown is obtained. The semi-finished primary substrate 11 remains flexible enough to perform the above-mentioned cut molding and slit molding without any problems, and the handling thereafter is extremely careful. In the method of the present invention, the primary substrate semi-finished product having such flexibility as described above is not transferred to the step of removing the cutting chips generated during the cut molding as it is, or to the firing step, but the primary substrate semi-finished product is Further, a step of heating and drying in air at 120 ° C to 180 ° C for 5 to 20 hours to obtain a semi-finished secondary substrate having a lower flexibility than the semi-finished primary substrate is interposed. In this step, for example, as shown in FIG. 4, a conveyor 12 that runs a primary substrate semi-finished product cut off from a strip-shaped green sheet by a cut press under the cut press.
It is achieved by running the conveyor at a constant speed for a predetermined time in an atmosphere of 120 ° C to 180 ° C. In this additional drying step, the binder agent remaining in the primary substrate semi-finished product is partially evaporated, the solid content ratio becomes large, and the flexibility is lowered. The drying conditions in the process may be appropriately determined depending on the mixing ratio of the binder agent and the boiling point thereof, but the boiling point is 450 ° C to 500 ° C.
When the mixing ratio of the binder agent in the above is 6 to 7%, the ambient temperature should be 140 ° C to 150 ° C and the time should be 10 to 12 hours. It was confirmed that it is the most preferable in maintaining the quality. This secondary substrate semi-finished product is then subjected to a step treatment for removing the cutting chips that are inevitably generated during the above-mentioned cut molding, but this secondary substrate semi-finished product obtained particularly by the method of the present invention is not flexible. Compared to the semi-finished product of the primary substrate, that is, its shape retention is improved, so even if the cutting chips are removed, the semi-finished product will not be deformed carelessly and In addition to being able to significantly reduce the possibility of defective products in the element thick film printing process,
Since it is also possible to give the secondary substrate semi-finished product a shape-retaining force that can withstand chucking such as vacuum chucking, it is possible to automate the above-mentioned chip removal work. The substrate semi-finished product that has completed the chip removal process is transported to the sintering / solidification process in the sintering furnace. As described above, according to the method of the present invention, the yield of the ceramic substrate can be remarkably improved, and the steps from the molding of the green sheet to the firing of the substrate can be made continuous, whereby the ceramic substrate for electronic parts can be obtained. The manufacturing efficiency of can be significantly increased.

[Brief description of drawings]

Fig. 1 is the manufacturing process diagram of the green sheet, and Fig. 2 is the first.
II-II direction enlarged arrow view of a figure, FIG. 3 is a top view of a primary substrate semi-finished product, and FIG. 4 is a perspective view which shows typically the example to transfer to the drying process after cut molding. 1 ... Suspension, 2 ... Roller, 3 ... Resin film, 4
…… Doctor blade, 5 …… Wall, 6 …… Liquid reservoir, 7…
... Peeling roller, 8 ... Rotating slitter, 9 ... Green
Sheet, 10a ... longitudinal slit, 10b ... horizontal slit, 11 ... primary substrate semi-finished product, 12 ... conveyor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhito Sakai, 21, Saiin Mizozaki-cho, Ukyo-ku, Kyoto City, Kyoto Prefecture Rome (72) Inventor, Shigeru Kambara 21, Mizozaki-cho, Saiin-ku, Kyoto, Kyoto Prefecture Mu Co., Ltd.

Claims (1)

[Claims] 1. A step of producing a highly flexible strip plate green sheet suitable for cut molding and slit molding from a liquid material containing a raw material, a solvent and a binder agent, a predetermined shape from the strip plate green sheet. The step of cutting and forming the intermediate product of 1) and forming the grid-like slits on the surface to obtain the semifinished product of the primary substrate. The above semifinished product of the primary substrate is heated and dried in air at 120 ° C to 180 ° C for 5 to 20 hours. And a step of obtaining a secondary substrate semi-finished product having a lower degree of flexibility than the primary substrate semi-finished product, and a step of firing and solidifying the secondary substrate semi-finished product in a heating furnace. Manufacturing method.