JP2003053716A - Equipment for forming film of ceramic green sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide equipment for forming a film of a ceramic green sheet which repairs a pinhole or a crack and has a structure having a drying part adjacently. SOLUTION: In this equipment, the position and the shape of the pinhole or the crack of the ceramic green sheet are caught by a laser light source or a visible light source, on one side of the sheet, and by a photosensor on the other side. The equipment has a sludge discharge part or a sludge printing part which can transfer, on the ceramic green sheet, a sludge having almost the same composition as the sheet to the position of the pinhole or the crack, and besides has the drying part which levels and dries the pinhole or the crack being repaired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic green sheet film used for manufacturing a laminated ceramic electronic device having a plurality of opposing internal electrode layers such as a laminated ceramic capacitor, a laminated piezoelectric actuator, a laminated chip inductor and a laminated piezoelectric transformer. It relates to the device.

[0002]

2. Description of the Related Art Recently, with the activation of the information technology industry, portable information terminal devices equipped with multilayer ceramic capacitors and multilayer chip inductors have become widespread, and multilayer ceramic capacitors and multilayer chip inductors have become smaller and have higher capacitance. Are being used, and the amount used is rapidly increasing. Along with this, the amount of semiconductor chips used has also increased rapidly, and the amount of laminated piezoelectric actuators used in semiconductor manufacturing equipment has also increased rapidly. Further, with the spread of notebook personal computers, the size of inverters for lighting LCD backlights has rapidly become smaller and the efficiency has increased, and these inverters for lighting LCD backlights are subjected to voltage conversion using mechanical vibration. The multi-layer piezoelectric transformer has been receiving attention and is being put to practical use as a boosting transformer for an inverter for lighting a liquid crystal backlight. These monolithic ceramic electronic devices are expected to become more and more widespread in the future in order to achieve high functionality of information technology industrial equipment, miniaturization of information terminal equipment, and high efficiency.

In these methods for producing a monolithic ceramic electronic device, a ceramic green sheet having a certain thickness is continuously drawn by stretching a carrier sheet running a slurry containing a mixture of a calcined ceramic powder, a binder and a dispersion medium and drying it. A common process is to start from the manufacturing process, then print and dry the internal electrodes on the ceramic green sheets, punch out the internal electrode-printed green sheets, and laminate and integrate a predetermined number of sheets in the mold. For forming the ceramic green sheet, the ceramic powders are bonded together, a certain sheet strength is provided for handling in the subsequent steps, and the binder is uniformly mixed in the ceramic powder for integration in the mold, and In order to continuously produce a ceramic green sheet having a constant thickness, a dispersion medium is added to a mixture of ceramic powder and a binder to form a starch syrup, and the slurry is placed on a carrier sheet such as a polyethylene terephthalate (PET) thin plate. Generally, a film forming apparatus is used in which a ceramic green sheet is manufactured by continuously stretching the film to a constant thickness, and then drying and removing the dispersion medium of the slurry on PET. A model diagram of a conventional film forming apparatus is shown in FIG. The structure of the device is a carrier sheet supply unit 36, a doctor blade 32.
The film forming unit, the drying unit 39, the winding and collecting unit 37, and the control unit 38, and the sludge 31 is stretched on the carrier sheet.
Then, the dispersion medium is removed in the drying section to manufacture the ceramic green sheet 35. In this model diagram, the doctor blade method is taken as an example of the film forming unit, but in order to obtain a stable green sheet film thickness for expressing the functions of various electronic devices, roll coater, die coater, gravure transfer, etc. This film forming method is also commonly used.

[0004]

Although the stability of the thickness is important as the quality of the ceramic green sheet produced, short circuit and insulation failure between opposing internal electrodes, which are related to the reliability of the laminated ceramic electronic device, are important. The occurrence of pinholes and cracks in the ceramic green sheet that causes
It is necessary to prevent it as much as possible. Therefore, in order to prevent foreign matter and air bubbles from entering during the production of the ceramic sludge, the environment for producing the ceramic sludge and the film deposition equipment room should be made a clean room, and the sludge should be created during the mixing work to create the sludge with a mixer. The foreign matter taken into the membrane is decomposed and removed with a mesh, and the air bubbles taken into the sludge are degassed in a vacuum. Furthermore, the rapid drying of the sludge will lead to the cracks. Various measures such as controlling the gradient have been made. However, although the mechanism has not been elucidated yet, when air is taken in as air bubbles when the sludge is supplied to the film forming device, or due to the adsorbed substances on the surface of the carrier sheet that are associated with static electricity, pinholes in the ceramic green sheet and It is difficult to completely prevent the occurrence of cracks. As a result, there is a problem that there is a limit to improving the reliability of the monolithic ceramic electronic device. There is a limit to prevent the occurrence of pinholes and cracks in the ceramic green sheet,
It is possible to detect pinholes and cracks in the generated ceramic green sheet with existing technology, but further, we investigated the technology to positively repair the pinholes and cracks.
No related art has been found in related art.

Therefore, an object of the present invention is to provide a film forming apparatus for continuously producing a high quality ceramic green sheet without pinholes or cracks in order to improve the reliability of a laminated ceramic electronic device. .

[0006]

According to the present invention, a ceramic green sheet having a certain thickness is continuously drawn by stretching it on a carrier sheet which runs a slurry containing a mixture of a calcined ceramic powder, a binder and a dispersion medium and drying it. In the film forming apparatus manufactured in the above, as a means for detecting pinholes and cracks in the thickness direction of the ceramic green sheet, a laser light source or a visible light source on one side in the thickness direction of the dried ceramic green sheet, and an optical sensor on the remaining one side. Part is arranged, based on the position and shape information of the pinholes and cracks of the ceramic green sheet detected by the optical sensor, the composition slurry almost the same as the ceramics is discharged to the pinholes or cracks or As a means of printing and repairing pinholes and cracks, a sludge discharge section or sludge printing section that can be moved on the green sheet is used. And Bei, further, the ceramic green sheet deposition device is obtained, wherein the structure provided with the dried portion adjacent to the repaired portion.

Further, there can be obtained a ceramic green sheet film forming apparatus characterized by a structure having a flat drying section for flattening and drying pinholes and cracks repaired by ejected or printed matter.

The optical sensor used in the present invention has a minimum of 5
A CCD image sensor or a light receiving sensor can be used as an optical sensor capable of detecting a pinhole having a diameter of micron or a crack having the same width. The information on the shape and position of the detected pinhole or crack is recorded in the recording device of the external computer, and the light type can be any light source such as laser beam, ultraviolet ray, visible ray, infrared ray, etc. that can be detected by the sensor. . The flat drying section can be easily constructed by installing a heater on the lower side of the carrier sheet or a dryer that blows out hot air on the upper side of the ceramic green sheet.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to Examples.

[0010]

Example 1 A film forming apparatus for a ceramic green sheet for a laminated ceramic capacitor will be described. Using a calcined powder of barium titanate as a ceramic raw material,
The binder and dispersion medium shown in Table 1 and the above-mentioned calcined powder of barium titanate were mixed in a mixer for 2 hours, passed through a nylon 400 # mesh, and vacuum defoamed for 30 minutes.
It was a slurry for ceramic green sheets. A ceramic green sheet having a width of 250 mm and a thickness of 15 μm was continuously formed on PET having a width of 300 mm and a thickness of 25 μm using the film forming apparatus shown in FIG. A visible light source 111 is arranged below the carrier sheet near the outlet of the drying unit of the film forming apparatus, and a light receiving sensor 112 is arranged above the facing carrier sheet. The light receiving sensor detects light transmitted through the ceramic green sheet. Information on the positions and shapes of pinholes and cracks is stored in an external storage device, and a slurry of the same composition as the ceramic is discharged from the slurry discharge part 113 arranged adjacently based on the information to the pinholes or crack parts. It ejected on the same principle as the inkjet printer head, and repaired pinholes and cracks. In this embodiment, since the thickness of the green sheet is as thin as 15 μm, it can be repaired by ejecting a small amount of ceramic slurry, and the thickness of the ceramic green sheet in the normal part and the repaired part is slightly changed, and the repair is performed. It is possible to easily dry the repaired portion later by the dryer 114 installed below the carrier sheet. Table 2 shows the state of occurrence of pinholes and cracks in the ceramic green sheet produced by the film forming apparatus of the present invention using 100 kg of sludge. For comparison, the state of occurrence of pinholes and cracks in the conventional film forming apparatus is also shown.

[0011]

[Table 1]

[0012]

Second Embodiment A film forming apparatus for a ceramic green sheet for a laminated piezoelectric actuator will be described. Using the calcined powder of lead zirconate titanate-based ceramics as a ceramic raw material, the binder and dispersion medium shown in Table 1 and the calcined powder of the lead zirconate titanate-based ceramics were mixed in a mixer for 2 hours to obtain nylon. After passing through a 200 # mesh, vacuum defoaming was performed for 1 hour to obtain a slurry for a ceramic green sheet. A ceramic green sheet having a width of 250 mm and a thickness of 100 μm was continuously formed on PET having a width of 300 mm and a thickness of 50 μm using the film forming apparatus as shown in FIG.
In this embodiment, since the thickness of the ceramic green sheet is thicker than the size of the pinholes or cracks, it is difficult to repair the discharge only by discharging, and the thickness of the repaired portion becomes thicker than the normal portion. The contact roller 21 for flattening the crack repair portion and the flat drying portion of the hot-air dryer 22 were added to the first embodiment. Table 2 shows the state of occurrence of pinholes and cracks in the ceramic green sheet produced by the film forming apparatus of the present invention using 100 kg of sludge. For comparison, the state of occurrence of pinholes and cracks in the conventional film forming apparatus is also shown.

[0013]

[Table 2]

From Table 2, when manufacturing a ceramic green sheet from 100 kg of slurry, 5-18 pinholes and 3-7 were generated in the conventional film forming apparatus.
It is apparent that the cracks generated at the points were completely repaired in the example of the present invention, the total number of defects was zero, and the quality of the ceramic green sheet was improved.

[0015]

As described above in detail, according to the present invention, in order to improve the reliability of the monolithic ceramic electronic device, high quality ceramic green sheets without pinholes or cracks are continuously provided. It is possible to provide a film forming apparatus to be manufactured.

[Brief description of drawings]

FIG. 1 is a model diagram of a film forming apparatus used in Example 1 of the present invention.

FIG. 2 is a model diagram of a film forming apparatus used in Example 2 of the present invention.

FIG. 3 is a model diagram of a conventional film forming apparatus

[Simple explanation of symbols]

11 Ceramic Sludge 12 Doctor Blade 13 Carrier Sheet 14 Sludge on the Carrier Sheet Before Drying 15 Ceramic Green Sheet 16 whose Dispersion is Dried in the Drying Section Carrier Sheet Supply Section 17 Ceramic Green Sheet and Carrier Sheet Winding and Collecting Section 18 Control unit of device 19 Drying unit 111 Visible light source 112 whose upper surface is made of transparent glass 112 Optical sensor 113 Head unit for discharging ceramic sludge 114 Drying unit 21 formed on the lower surface of a carrier sheet 21 Contact roller flat unit 22 Hot air drying unit 31 Ceramic Sludge 32 Doctor Blade 33 Carrier Sheet 34 Pre-Dry Sludge Stretched on the Carrier Sheet 35 Ceramic Green Sheet whose Dispersion is Dried at the Drying Section 36 Carrier Sheet Supply Section 37 Ceramic Green Sheet and Key Carrier sheet winding and collecting unit 38 Device control unit 39 Drying unit

Claims (2)

[Claims] 1. A film forming apparatus for continuously producing a ceramic green sheet having a constant thickness by stretching on a carrier sheet running a slurry containing a mixture of a calcined ceramic powder, a binder and a dispersion medium, and continuously producing a ceramic green sheet having a constant thickness. As a means to detect pinholes and cracks in the thickness direction of the sheet, a laser light source or visible light source is arranged on one side in the thickness direction of the dried ceramic green sheet, and an optical sensor section is arranged on the other side, and the optical sensor detects it. Based on the information on the positions and shapes of the pinholes and cracks of the ceramic green sheet, the composition of the ceramics is ejected or printed at the positions of the pinholes and cracks to repair the pinholes and cracks. As a means, it has a sludge discharge part or sludge printing part that can move on the green sheet, and it also has a dry part adjacent to the repair part. A ceramic green sheet film forming apparatus characterized by a structure including a drying section. 2. The ceramic green sheet film forming apparatus according to claim 1, comprising a flat drying section for flattening and drying pinholes and cracks repaired by a discharged material or a printed material. Deposition apparatus.