JPH0423808B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing laminated electronic components. Many multilayer electronic components have been put into practical use, such as thick film resistor networks, multilayer ceramic capacitors, multilayer ceramic varistors, and multilayer ceramic wiring boards. These laminated electronic components are usually made by forming conductors, electrodes, resistors, dielectrics, etc. on dielectrics, insulators, etc. using the thick film method, and laminating them.
Manufactured using a sintering manufacturing method. In forming electronic circuit patterns using the conventional thick film method, there are large variations in circuit pattern dimensions and printing thickness during thick film printing, so accuracy is high.
It has been difficult to produce parts with little variation in properties. Furthermore, with conventional thick film methods, it is difficult to manage each paste for conductors, resistors, dielectrics, etc., and in order to form reproducible circuit patterns, it is necessary to adjust the paste and printing conditions each time. This was a major cause of lower productivity. Furthermore, when printing by the thick film method, the utilization rate of the paste is extremely poor, which causes an increase in costs, especially when expensive metals such as gold, platinum, and palladium are used for conductors. The present invention eliminates all of these drawbacks, improves the precision of laminated electronic components, has less variation in characteristics,
Moreover, it is possible to significantly improve productivity,
The purpose of the present invention is to provide a method for manufacturing laminated electronic components that is also excellent in mass production. The present invention is a process of producing a green sheet made of a mixture of an inorganic material powder and an organic substance into a predetermined shape for each of a plurality of types of inorganic materials, and a process of forming one or more of these green sheets into a predetermined shape. a process of punching out a raw sheet of a type other than these and pressing it onto the sheet in the shape at the time of the initial sheet production, and manufacturing the first sheet in which the raw sheet punched into a predetermined shape is pressed onto the surface of the sheet. The present invention is characterized by comprising the steps of laminating, pressing, and firing one or more raw sheets in the shape of a blank sheet and one or more raw sheets of the same type having a punched raw sheet on the surface of which is not pressed. That is, in the present invention, materials such as conductors, resistors, and dielectrics constituting a laminated electronic component are formed into green sheets of a certain shape, and one or more of these green sheets is molded into a predetermined shape using a mold or the like. The major feature of this method is that it can be punched into a size and shape as well as press-bonded onto a type of raw sheet other than the punched raw sheet. In this way, the method of forming electrodes, resistors, etc. by punching them with a mold and crimping them can significantly reduce dimensional variations compared to the conventional thick film method, resulting in improved accuracy and improved characteristics. Variations can also be reduced. Furthermore, the unused part of the green sheet after punching it can be easily recycled into a new green sheet, so there is almost no loss during the material process, and this makes it possible to use precious metal conductors in the form of green sheets. If so, significant cost reductions can be achieved. Furthermore, since the present invention mechanically punches out raw sheets, continuous processing is easier than in conventional printing methods, and automation and mass production are possible. Furthermore, since no paste is used,
Management during production becomes easier, and there is no need to set conditions every time, and productivity can be significantly increased. Next, the present invention will be explained with reference to the drawings while comparing it with a conventional method for manufacturing a laminated electronic component. Here, the process of manufacturing a multilayer ceramic capacitor will be explained as an example. FIGS. 1a to 1c show diagrams of a printing jig for printing a dielectric green sheet in the process of forming internal electrodes on the dielectric green sheet of a conventional multilayer ceramic capacitor. On the dielectric green sheet 11 formed by the casting method shown in FIG. 1a, screen printing is performed as shown in FIG. 13, the internal electrode paste 13 is formed into the shape of an electrode as shown in FIG. Raw sheets are laminated and pressed to form laminated raw chips. This raw chip is sintered to produce a multilayer chip capacitor. On the other hand, the method for forming internal electrodes according to the present invention will be explained using FIG. Figures 2 a to c show the dielectric raw sheet 21, molds 22, 22', and internal electrode raw sheet 23 in each process.
This figure shows the diagram. On the dielectric raw sheet 21 formed by the casting method shown in FIG. 2a, a metal powder that will become an internal electrode is placed between the punching dies 22 and 22' as shown in FIG. 2b. By placing the raw internal electrode sheet 23 formed by the casting method on the holder and applying pressure or pressure and heat simultaneously from above, the raw internal electrode sheet 23 is formed as shown in FIG. 2c.
is crimped and formed on the dielectric green sheet 21. The dielectric raw sheet with internal electrodes formed in this way is laminated and pressed together with the dielectric raw sheet without internal electrodes formed thereon, and after sintering, it becomes a multilayer chip capacitor. A feature of the present invention is that the thickness of the electrode is constant and can be made extremely thin because a raw electrode sheet is used instead of using a screen printing method using paste. In multilayer ceramic capacitors, the internal electrodes have traditionally been formed by screen printing as shown in Figure 1, but when attempting to reduce the thickness of the electrodes in order to reduce costs, the thickness becomes uneven during printing. After sintering, the internal electrodes may become island-like or partially broken, making it impossible to obtain the capacitance as designed, and increasing the dielectric loss, making it impossible to achieve an electrode thickness of 2 μm or less. . However, if the internal electrodes of a multilayer ceramic capacitor are formed by the method shown in FIG. 2 of the present invention, the thickness of the raw sheet that will become the internal electrodes can be formed more uniformly than when the internal electrodes are formed by the casting method. The internal electrodes do not become islands or break, and the thickness of the internal electrodes can be reduced to 2 μm or less. In addition, the remaining portion of the internal electrode green sheet that is not used for crimping in FIG. 2 can be recycled and used as a green sheet again, so that the loss of internal electrode material is greatly reduced. The details of the present invention will be explained below with reference to Examples. (Example 1) The thickness was measured by the slip casting method which is commonly performed using a dielectric powder mainly composed of barium titanate and a metal palladium powder.
A 40μm dielectric green sheet and a 5μm thick metal palladium green sheet were made. At this time, polyvinyl butyral was used as a binder for the green sheet. After punching this dielectric raw sheet into a shape of 40 mm x 60 mm, 5 mm
A dielectric raw sheet 21 is punched out using metal molds 22 and 22' from a metal palladium raw sheet 23 with a size of 3 mm.
It was crimped and formed on top. A multilayer ceramic capacitor was fabricated by laminating, crimping, and sintering 10 raw dielectric sheets with electrodes formed on them and arranging a raw dielectric sheet with no electrodes formed on the outside of these 10 sheets. Then, the capacitance and dielectric loss were measured at a frequency of 1kHz. Table 1 shows the variation in the thickness of the electrode after sintering, the measured value of the capacitance with respect to the designed value, and the value of the dielectric loss. For comparison, this table shows measurement data of a multilayer ceramic capacitor manufactured by the conventional screen printing method.

[Table] This is a sample.
Table 1 shows that when internal electrodes are formed by the method of the present invention, there is little variation in electrode thickness, and when comparing the same electrode thickness, the capacitance decrease rate with respect to the designed value is small. Furthermore, even if the internal electrodes are thin, there is no cutting of the electrodes, and the dielectric loss is small and shows good values. As described above, it is clear that by forming internal electrodes by the method of the present invention, the variation in characteristics and precision productivity are significantly improved compared to the conventional screen printing method. (Example 2) Insulation with a thickness of 50 μm was made using the commonly used slip casting method using an insulator powder containing alumina that can be sintered at around 900°C, a resistor powder containing silver/palladium powder, and ruthenium oxide. We made a body sheet, a 15 μm thick silver palladium raw sheet, and a 30 μm thick resistor raw sheet. At this time, polyvinyl alcohol was used as a binder for the raw sheet. On this insulator green sheet 31 (FIG. 3a), a silver palladium green sheet 3 in the process shown in FIG.
3 and resistor raw sheet 35 into molds 32 and 3, respectively.
2', 34, and 34' were punched out and crimped at the same time to form a conductor layer and a resistor layer. (Fig. 3b to e) A raw insulator sheet with these conductor layers and resistor layers crimped together (Fig. 3e) and a single raw insulator sheet 31 to which nothing is crimped are laminated and crimped. A raw resistor chip was prepared, and after firing it, the resistance was measured. The dimensions of the resistor are 2mm x 10mm after sintering and the thickness is
It was 25μm. Table 2 shows the resistance value and the variation in resistance value of this resistor. Table 2 shows, for reference, data when resistors were formed by a conventionally used screen printing method.

[Table] This is a sample.
As is clear from Table 2, according to the manufacturing method of the present invention, highly accurate resistors can be formed with very little variation in resistance value. In this embodiment as well, the unused portions of the silver-palladium raw sheet and the ruthenium oxide resistor raw sheet can be reused, and the material cost for the product can be significantly reduced compared to the conventional paste printing method. Furthermore, since it is not necessary to determine screen printing conditions for matching the resistance values, productivity can be significantly improved. (Example 3) A 50 μm thick insulating sheet and a 15 μm thick insulating sheet were prepared by using the commonly used slip casting method, respectively, using an insulating powder containing alumina and sinterable at around 900°C and gold powder. I made a Kinsei sheet. Acrylic resin was used as the binder for the raw sheet at this time. The insulating raw sheet 41 produced in this way was
It is punched into a shape of mm x 100 mm (Fig. 4a), after which through holes are formed (Fig. 4b), and molds 42, 42' are formed on this sheet 41 as shown in Fig. 4o.
The metal sheet 43 was then punched out and crimped to form a circuit. (Fig. 4 d) One or more layers of the insulating raw sheet (Fig. 4 d) with the circuit formed in this way and one or more insulating raw sheets 41 are laminated to form a raw ceramic substrate, and this is sintered. Then, a ceramic wiring board or a multilayer ceramic wiring board was produced. Table 3 shows the results of measuring the variations in conductor width and conductor resistance per unit of the ceramic substrate thus formed. This table also shows for reference the variation in conductor resistance when conductors are formed using the conventional screen printing method.

【table】

[Table] This is the manufactured sample.
This table shows that if the method of the present invention is followed, a substrate with very little variation in conductor resistance can be obtained. As shown in the examples above, when laminated electronic components are manufactured by the manufacturing method of the present invention, electronic components with very good precision, little variation in characteristics, high productivity, and excellent mass production can be manufactured. becomes possible.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a method of forming electrodes using a conventional screen printing method. FIG. 2 is a diagram showing a method for forming electrodes when manufacturing a multilayer ceramic capacitor according to the present invention. FIG. 3 is a diagram showing the process of forming a resistor using the method of the present invention. FIG. 4 is a diagram showing the process of forming a multilayer ceramic wiring board using the method of the present invention. In the figure, 11, 21... dielectric raw sheet,
12... Screen, 13... Internal electrode paste, 14... Squeegee, 22, 22'... Mold,
23... Internal electrode raw sheet, 31, 41... Insulator raw sheet, 32, 32', 34, 34'... Mold, 33, 43... Silver palladium raw sheet, 35
... Resistor raw sheet, 42, 42' ... Mold.

Claims (1)

[Claims] 1. A process of producing green sheets made of a mixture of inorganic material powder and organic matter into fixed shapes for multiple types of inorganic materials, and punching one or more types of these green sheets into a predetermined shape. , a step of pressing the raw sheet punched into this shape onto the raw sheet having the shape used in the initial sheet production with a type of raw sheet other than these, and pressing the raw sheet punched into the predetermined shape onto the surface of the sheet. A laminated electronic component characterized by comprising the steps of laminating, crimping, and firing one or more green sheets of the same type, and one or more green sheets of the same type, the surfaces of which have not been press-bonded with punched green sheets. Production method.