JPS6083314A - Laminated ceramic capacitor and method of producing same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention is a multilayer ceramic capacitor and its manufacturing method.
; 6iVr IJJ 117-,-This type of multilayer ceramic capacitor has a structure shown in the perspective cross-section of FIG.
Internal electrodes 1 are formed between layers inside the ceramic dielectric 3. For ease of explanation, an exploded perspective view is assumed in which the external electrode z is removed from FIG. 1 and only a pair of laminated layers are taken out, and this is shown in FIG. 2.

A method of manufacturing the ceramic dielectric material 3 having such an internal electrode 1 formed thereon is described in detail in Japanese Patent Application Laid-Open No. 53-68853 as a comparison between the conventional technique and the new technique.

That is, in conventional multilayer ceramic capacitors of this type, internal electrodes are formed on green sheets before firing, and after stacking these, a firing process is performed at high temperature to produce a ceramic dielectric.

In addition, a construction method that integrates laminates is commonly used.

Conventional laminated ceramics and capacitors undergo high-temperature firing in one manufacturing process, so the internal electrodes are
Precious metals such as platinum (Pt) and palladium (Pd) are used, and they account for a high proportion of the manufacturing cost of the inner S electrode.
A device with a large n-electrical MM has the drawback of being extremely expensive. By firing at this high temperature (over 1300℃) and in air! 17 Since the internal electrodes are used to prevent problems such as oxidation, melting, and reaction with ceramics and lithium, there is no attempt to lower the firing temperature. A lead-based ceramic composition that can be fired at about 900'0 was developed.

However, in ceramic compositions containing raw materials such as niobium (Nb-containing tungsten C4) that can be fired at relatively low temperatures, ceramics that use noble metals for internal electrodes,
Although it is an improvement over the 0% capacitor, it is still not sufficient.The ceramic capacitors used in the Daisha tray will inevitably be larger and require more raw materials, so there is a limit to how much the price can be reduced./ζ-This ti that fundamentally solves the problem
c is a relational expression known in principle. Naturally, savings were considered.

Although it is possible to make the dielectric thickness d small and thin, it is not possible in multilayer ceramic capacitors.

Since the ceramic dielectric and the P3 part electrode are integrated, the thickness of the internal electrode increases relatively, which may lead to volumetric contraction during firing and an imbalance between thermal expansion and contraction after firing. found. As a result, delamination and cracks occur in the laminate, and even if it is commercialized, when a voltage is applied, the piezoelectric effect and latent internal stress combine to cause minute cracks, which can lead to dielectric breakdown. This will significantly degrade the quality of multilayer ceramic capacitors.

Therefore, the reduction in the thickness of the dielectric and the reduction in the thickness of the internal electrodes are very closely related, and as the thickness of the dielectric is reduced, the thickness of the internal electrodes must also be reduced.

On the other hand, since the internal electrodes of I class generally use precious metals, everyone would like to use as little as possible.
(micron) to 6.0μ (micron). This is because the internal electrodes are formed by screen printing a paste material, so the minimum thickness is limited by the thickness of the printing screen. Fig. 3 is a top view for explaining this, and Fig. 3 shows the principle of screen printing. do. The thickness of this scraped paste-like electrode material 6 corresponds to the thickness of the internal electrode, and is greatly shaded +7 by the original surface of the screen 4.

Usually, silk, stainless steel, nylon, etc. are used for the screen 4, and the I! i AM can song Eri is rr (
In reality, the emulsion for forming the mask pattern gold is coated on this by approximately 10 microns (microns), so it is more than 35 microns (microns/).' The paste-like electrode coating material 6 is printed After being applied and dried,
Because it is fired, its thickness rJ: It becomes thinner than when it is applied, but the reduction rate varies depending on the concentration of the paste electrode material and the type of electrode gold.The minimum average thickness after firing is 2 as described above. The range is from .0μ to 60μ.

The object of the invention is to eliminate these conventional drawbacks, provide a high quality lη ceramic capacitor, and a method for manufacturing the same, which is reliable, has high quality, and is inexpensive.

That is, in the uninvented multilayer ceramic capacitor, the average thickness of the internal electrode of the capacitor element made of a ceramic dielectric material formed by high-temperature firing is O11μ per 1/# of laminated layers.
(It is characterized by having a thickness of more than microns and less than 1.5μ (microns), and its manufacturing method involves reducing pressure and forming a predetermined electrode on a medium that does not resonate with the forceps. This electrode is characterized in that it is transferred onto the gold ceramic green sheet to form a single layer of internal electrodes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings and examples.

FIG. 4 is a perspective view in which the entire electrode pattern is simplified to explain one embodiment of the present invention. Medium whose composition does not change in a reduced pressure atmosphere, such as polyester film
A thin layer of Ni-type agent gold such as Teflon or 7-Licon (not shown) is applied onto a carrier sheet 9 made of a mechanical film (not shown), and an electrode thin film of 0.1 μm to 1.5 μm is formed thereon by thin film forming means such as vapor deposition or sputtering. Form 8. Carrier sheet 9 with thin electrodes made in this way
(FIG. 6) is inverted and stacked on top of the green sheet 10 so that the electrode thin film 80 surface of the carrier sheet 9 is in contact with the green sheet io. The ceramic green sheet 10 is used after being peeled off from the carrier sheet 9 in advance, as shown in FIG. To attach the electrode thin film 8 and the green sheet 10, an appropriate means such as a heat press is used.
Next, as shown in FIG. 8, the carrier sheet 9 is peeled off to obtain a green sheet 10 to which the electrode thin film 8 is attached. All of the green sheets with electrode thin films thus obtained are stacked and hot pressed to form a laminate as shown in Figure 7(a).The cross section of the laminate A-A' in Figure 7(a) is As shown in Fig. 7 fbJ, the electrode thin films 8 (internal electrodes) are arranged alternately, so by completely cutting at the B-B' position and firing, the multilayer ceramic capacitor element (from Fig. 1, the external electrodes 2
(hereinafter abbreviated as multilayer ceramic chip).

The thickness of the internal electrode of the multilayer ceramic capacitor element thus obtained is determined by the thickness of the electrode thin film 8 formed on the carrier sheet 9 shown in FIG. The thickness of the internal electrodes can be controlled relatively easily by using the sputtering technology of Hypuri and DeIe resistive materials. This thickness is 0. l
μJ: When the thickness becomes too thin, there will be more cases where the cap will come off due to electrode breakage, and when it exceeds 15μ, baking soldering becomes susceptible to thermal shocks, resulting in a decrease in the quality of products. Especially when the thickness of the ceramic green sheet is 1.5μ or less, the quality of the capacitor is affected by the thickness of the internal electrodes, which has a markedly different yield rate.

As described above, it is possible to reduce the average thickness of internal electrodes (electrode thin films) after firing to 01μ or more and 1.5μ or less by film forming means such as vapor deposition or sputtering, and as a result, ceramic It is possible to prevent low purchasing costs due to thinning of the dielectric film, and also to reduce the amount of expensive internal electrode materials used. Furthermore, ceramic S- is used to make the film thinner (paraphrase 1)
- Thinner ceramic green sheets) has the advantage that if the electrode area is the same, the electrostatic weight will increase in proportion to the thinner dielectric layer. This greatly contributes to the miniaturization of ceramic capacitors.

In this way, by virtue of uninventiveness, we can produce laminated ceramic capacitors at low cost, with high quality, and in a simple manner.

It has the advantage of being able to supply

[Brief explanation of drawings]

Section 1 is a cross-sectional perspective view of a shield ceramic capacitor, Fig. 2 is a perspective view taken out from Fig. 1 by adding only a pair of layers, and Fig. 3 is a perspective view of the principle of electrode printing. Figures 4 to 8 are diagrams explaining the invention in detail, Figure 4 is a simplified perspective view of the electrode pattern, and Figure 5 shows the state in which the ceramic green sheet is completely peeled off from the carrier sheet. Figure 6 is a perspective view showing a state in which a polarized film with an ultra-thin film is stacked on a ceramic green sheet (FIG. 7); (b) is a cross-sectional view showing a stacked laminate. FIG. 8 is a perspective view showing a state in which a carrier sheet is peeled off from a ceramic green sheet with an electrode thin film. (Explanation of symbols) 1...Internal electrode, 2...External electrode, 3
... Ceramic dielectric, 4 ... Screen, 5 ... (screen) mesh, 6 ...
...Paste-like cathode material, 8... Electrode thin film, 9
... Carrier sheet, 10 ... Ceramic green sheet, 11 ... Yes aA fill h sort. L L l lol at the diagram? Zuken 3 Diagram θ z 4 Diagram 6 Diagram β'a'a' Tsuri 7 Diagram θ Diagram procedural amendment (voluntary) Commissioner of the Japan Patent Office 1, Indication of the case 1988 Patent Application No. 191849
No. 2, Title of the invention Laminated ceramic, Kucontensa and its manufacturing method 3, Relationship to the amended case Applicant 5-33-1 Shiba, Minato-ku, Tokyo (423) NEC Corporation Representative Tadahiro Sekimoto 4 , Agent Address: 108 Tokyo Kogyo; [Sumitomo Sanda Building, 37-8 Shiba 5-chome, Miyakominato-ku (Contact address: Nippon i-Kashuppansha Licensing Department) -5 Subject of supplement (1) Details of the invention in Specification 1 "Explanation" column. (2) Drawing 6, contents of amendment (2) Changed the word ``Seru'' to ``Zeteta'' in line 18 of the same page. (3) "Carrier sheet made of film" on page 7, lines 9-10 is replaced by "film sheet." (4) Sheet 9J in line 10 of the same page was corrected to “Sheet IIJ” (5) Lines 14 and 16 of the same page and lines 2 and 13 of page 8
~ 14th line "Carrier sheet 9" to "Organic film sheet 11J" J positive. It goes without saying that the ceramic green sheet 10 may be formed by attaching the electrode film 8 and then peeling it off from the carrier sheet 9. Add J0(8) [(
(hereinafter abbreviated as multilayer ceramic chip) J is deleted. (9) Keep rl and 5J in the 9th negative 3rd row to "15". 4. Change the reference number "9" in Figure 4 of the drawings to "11".
J Masaru (see Zhu MP correction in the attached drawing). 7″F-~, Agent Patent Attorney Uchihara (5, [-

Claims (2)

[Claims] (1) The average thickness of the internal electrodes of the ceramic capacitor formed by high-temperature firing is 0.00 mm per laminated layer. A laminated ceramic material, Kucontensa, whose characteristic is 1 (micron) or more and 1.5 μ (micron) or less. (2) A method characterized in that a predetermined electrode hair is formed on a medium whose composition does not change in a manufacturing environment under reduced pressure, and then transferred onto a ceramic green sheet on this electrode to form an internal electrode. A method for producing negative layer ceramic condensate. .