JP2005015255A - Method of manufacturing thin layer ceramic sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a thin layer ceramic sheet by which the thin layer ceramic sheet having small warpage and excellent surface smoothness is surely provided without necessitating a complicated washing process. <P>SOLUTION: In the method of manufacturing the thin layer ceramic sheet, a laminated body is obtained by alternately laminating ceramic green sheets and unsintered metallic films comprising conductive paste primarily comprising a metal consisting of at least one kind of platinum and iridium, the laminated body is fired to obtain a sintered compact 1 and metallic films 5 and 6 formed in the sintered compact 1 is separated from the thin layer ceramic sheets 2-4 by applying vibration with ultrasonic treatment to the sintered compact 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００２４】
（実施例４）
出発原料として、Ｐｂ_３Ｏ_４、ＴｉＯ_２、ＺｒＯ_２、ＮｉＯ及びＮｂ_２Ｏ_５の各セラミック粉末を用意した。このセラミック粉末を用い、Ｐｂ_１．０（Ｎｉ_１／２Ｎｂ_１／２）Ｏ_２．０−（Ｚｒ_０．３５Ｔｉ_０．４５）Ｏ_３の組成を構成するセラミックスを得るように、これらのセラミック粉末を秤量し、以下実施例１と同様にしてセラミック焼結体を得た。また、実施例４においても、このセラミック焼結体を用い、実施例１と同様に超音波洗浄機を用いて振動を与えた。その結果、金属膜から薄層セラミック板が分離され、薄層セラミック板を容易に取り出すことができた。
【００２５】
（実施例５，６）
未焼結の金属膜を構成する導電ペーストとして、Ｐｔを主体とするものに代えて、実施例５ではＩｒ粉末を主体とするもの、実施例６では、ＰｔとＩｒとを重量比で５０対５０で含む導電ペーストを用いたことを除いては、実施例４と同様にして焼結体を得、かつ実施例４と同様に超音波処理を行ない、薄層セラミック板を得た。
【００２６】
（比較例２）
未焼結の金属膜を構成する導電ペーストとして、Ａｇ及びＰｄを重量比で３０対７０で含むものを用いたことを除いては、実施例４と同様にしてセラミック焼結体を得、超音波処理を行なった。
【００２７】
（実施例４〜６及び比較例２の評価）
下記の表２に示すように、実施例４〜６では、超音波処理により、薄層セラミック板は金属膜から良好に分離され、薄層セラミック板を取り出すことができた。従って、薄層セラミック板と金属膜との密着力を測定することはできなかった。
【００２８】
これに対して、比較例２では、金属膜が薄層セラミック板から剥がれず、両者の間の密着力を測定したところ、１０１ＭＰａであった。
また、実施例４〜６においても、実施例１と同様にして、表面が平滑であり、反りのない薄層セラミック板を得ることができた。
【００２９】
【表２】

【００３０】
実施例１〜６の結果から明らかなように、本発明に係る薄層セラミック板の製造方法では、未焼結の金属膜が白金及びイリジウムのうち少なくとも１種からなる金属を用いて構成されているため、セラミック焼結体を超音波処理することにより、金属膜からセラミックグリーンシートの焼成により得られた薄層セラミック板が容易に取り除かれる。これは、Ａｇ−Ｐｄ合金やＡｇまたはＰｄでは、焼成に際し、酸素を介して金属がセラミックスと強固に結合しているのに対して、ＰｔやＩｒは、酸素との結びつきが弱いためである。すなわち、Ｐｔ及びＩｒのうち少なくとも１種からなる金属を用いて構成された金属膜は、セラミックスとの接着強度がかなり低いため、超音波処理により振動を与えるだけで、薄層セラミック板が金属膜から容易に分離される。
【００３１】
なお、上記実施例１〜６では、Ｐｂ系セラミックスが薄層セラミック板を構成するセラミック材料として用いられたが、チタン酸バリウム系セラミックスのような他のセラミックスを用いてもよい。
【００３２】
【発明の効果】
以上のように、本発明に係る薄層セラミック板の製造方法では、白金及びイリジウムのうち少なくとも１種からなる金属を用いて構成された未焼結の金属膜と、セラミックグリーンシートとが交互に積層されて積層体が構成され、該積層体を焼成することにより焼結体が得られている。従って、白金及びイリジウムのうち少なくとも１種からなる金属膜と、セラミックグリーンシートの焼成により得れた薄層セラミック板との密着強度が低いため、第３の工程において超音波処理等により外力を与えることにより、金属膜と薄層セラミック板との接合を容易に解くことができる。よって、薄層セラミック板を超音波処理等の外力を加えるだけで容易に取り出すことができる。
【００３３】
また、積層体を焼成することにより焼結体が得られているため、焼結体中の薄層セラミック板を金属膜により支持されているため、薄層セラミック板の厚みが薄い場合であっても反りが少ない薄層セラミック板を得ることができる。よって、本発明によれば、反りが少なく、表面平滑性に優れた、例えば厚み２０μｍ以下の非常に薄いセラミック板を安定に供給することが可能となる。
【図面の簡単な説明】
【図１】本発明の一実施例において用意されるセラミック焼結体を示す正面断面図。
【図２】比較例１において、金属膜とセラミック板との密着強度を評価するために試験方法を説明するための模式的正面断面図。
【図３】（ａ）及び（ｂ）は、従来の薄層セラミック板を得る方法の一例を説明するための図であり、（ａ）は用意されるセラミック焼結体を示す正面断面図、（ｂ）は電気分解により金属膜を溶解する工程を示す模式的正面断面図。
【符号の説明】
１…セラミック焼結体
２〜４…薄層セラミック板
５，６…金属膜
２１…セラミック焼結体（比較例１）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a ceramic plate, and more particularly to a method for manufacturing a ceramic plate having a small thickness.
[0002]
[Prior art]
In recent years, ceramic electronic components such as IC substrates and capacitors have been made thinner and smaller. Therefore, a thinner ceramic plate is required as a ceramic plate for constituting an electronic component.
[0003]
An example of a manufacturing method that satisfies such requirements is disclosed in Patent Document 1 below. That is, in the method described in Patent Document 1, first, a resin sheet is prepared in which an oxide having a melting point higher than the firing temperature of the ceramic is contained in the resin. A laminate is obtained by alternately laminating the resin sheet and the ceramic green sheet, and the laminate is fired. By firing, the ceramic green sheet becomes a ceramic plate, and the resin in the resin sheet is scattered. Thus, a thin ceramic plate is obtained by separating the ceramic plate from the remaining unsintered oxide layer.
[0004]
Further, Patent Document 1 discloses another method using a resin paste in which an oxide having a melting point higher than the firing temperature of ceramics is dispersed in a resin. That is, first, a resin paste is applied to a ceramic green sheet, and the ceramic green sheet to which the resin paste is applied is laminated to prepare a laminate. And it is supposed that a ceramic board can be isolate | separated from the remaining unsintered oxide layer by baking this laminated body like the above.
[0005]
Moreover, the following patent document 2 discloses a method for manufacturing a ceramic sheet shown in FIGS. 3 (a) and 3 (b). That is, first, as shown in FIG. 3A, a laminate 10 is prepared in which unsintered metal films 11 and 12 and ceramic green sheets 13, 14, and 15 are alternately laminated. And the laminated body 10 is baked and a sintered compact is obtained. Thereafter, as shown in FIG. 3 (b), the sintered body 10A obtained as described above is immersed in the electrolytic solution 16, and a positive potential is applied to the metal films 11, 12, thereby providing a metal film 11, 12 is electrolyzed to dissolve the metal films 11 and 12. Thus, since the metal films 11 and 12 are melted, a thin ceramic plate is obtained.
[0006]
Further, Patent Document 2 discloses another method in which the metal film is dissolved by immersing the sintered body in an acid capable of dissolving the metal film.
Further, conventionally, after obtaining a plate-like molded body from a ceramic slurry, when the plate-like molded bodies are stacked and fired, ceramic powder is interposed between the plate-like molded bodies in order to prevent adhesion between the molded bodies. There is known a method in which firing is performed in a state of being performed.
[0007]
[Patent Document 1]
JP 2000-169244 A [Patent Document 2]
JP-A-8-267438
[Problems to be solved by the invention]
In the method described in Patent Document 1, a resin sheet or a resin paste in which the oxide is dispersed in a resin is used to separate the ceramic plates. However, although the resin is scattered during firing, the oxide remains unsintered even after firing, and remains attached to the obtained ceramic plate, and the residual oxide cannot be easily removed. Therefore, in order to remove the oxide adhering to the obtained ceramic plate, a complicated cleaning process has to be performed. Even after washing, oxides that cannot be removed tend to remain. Therefore, the smoothness of the surface of the obtained ceramic plate was not sufficient.
[0009]
On the other hand, in the method described in Patent Document 2, the thin ceramic plate is separated from the sintered body by melting the metal film. When the metal film starts to be dissolved by electrolysis, power supply for electrolysis is provided. Since the electrical connection between the line and the metal film was interrupted, the metal film could not be continuously dissolved.
[0010]
Furthermore, in order to dissolve the metal film, in the method using an inorganic acid such as hydrochloric acid or nitric acid for dissolving the metal film, usable acids are limited. Moreover, when such an inorganic acid is used, the obtained ceramic board may deteriorate with an acid.
[0011]
The object of the present invention is to eliminate the above-mentioned disadvantages of the prior art, and to stably obtain a thin-layer ceramic plate continuously without requiring a complicated cleaning step, and to deteriorate the obtained ceramic plate. It is an object of the present invention to provide a method for producing a thin-layer ceramic plate that hardly occurs and has excellent surface smoothness.
[0012]
[Means for Solving the Problems]
The method for producing a thin ceramic plate according to the present invention includes a first step of obtaining a laminate by alternately laminating ceramic green sheets and an unsintered metal film formed of a conductive paste, and the laminate A second step of obtaining a sintered body in which the metal film and a thin ceramic plate obtained by firing the ceramic green sheet are integrated by firing the body, and the metal in the sintered body A third step of obtaining a thin-layer ceramic plate by separating the membrane and the thin-layer ceramic plate, wherein in the first step, the unsintered metal film is at least one of platinum and iridium Characterized in that the metal film and the thin ceramic plate in the sintered body are separated by applying an external force to the sintered body in the third step. To do.
[0013]
Further, the method of applying the external force is not limited as long as some external force is applied to the sintered body, and there is a sufficient effect even by manual work or barrel treatment.
In a specific aspect of the method for producing a thin ceramic plate according to the present invention, a method of applying ultrasonic treatment is used as the method of applying the external force in the third step.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention.
[0015]
(Example 1)
As starting materials, ceramic powders of Pb ₃ O ₄ , TiO ₂ , ZrO ₂ and SrCO ₃ were prepared. This ceramic powder was weighed so as to constitute a composition of Pb _0.98 Sr _0.02 (Zr _0.45 Ti _0.55 ) O ₃ and wet-mixed with a ball mill to obtain a mixed powder. The obtained mixed powder was calcined at 800 ° C. for 2 hours and pulverized to obtain a calcined powder. A binder and a plasticizer were mixed with the calcined powder to obtain a ceramic slurry, and the ceramic slurry was formed by a doctor blade method to obtain a ceramic green sheet having a thickness of about 30 μm.
[0016]
A conductive paste composed of Pt powder is formed on the entire surface of a rectangular ceramic green sheet obtained by cutting the ceramic green sheet into a desired size so that the thickness after drying is about 5 μm. A ceramic green sheet on which an unsintered metal film obtained as described above was formed was prepared. A plurality of rectangular ceramic green sheets on which the unsintered metal film is formed are stacked and pressed by hot pressing at 60 ° C. and 196 MPa, and the unsintered metal film is stacked on the unsintered metal film. A plate-like molded body made of sintered ceramic was obtained. In addition, the ceramic green sheet in which the metal film was not formed was used for the uppermost ceramic green sheet.
[0017]
The molded body obtained as described above was heated to remove the binder component at a temperature of 500 ° C., and then fired at a temperature of 1050 ° C. to obtain a plate-like ceramic sintered body. FIG. 1 is a sectional view of the ceramic sintered body obtained in this way. The ceramic sintered body 1 is composed of thin ceramic plates 2 to 4 obtained by firing the ceramic green sheet and metal films 5 and 6 obtained by sintering the unfired metal film. Have a laminated structure. The ceramic sintered body 1 obtained in this way is put into an ultrasonic cleaning machine (manufactured by Inoue Seieido, product number: US-3) together with water, and subjected to ultrasonic treatment at a voltage of 3 to 5 V for several minutes to several tens of minutes A vibration was given.
By the ultrasonic treatment, the metal film made of Pt and the thin ceramic plate were disconnected, and a thin ceramic plate having a thickness of about 20 μm could be obtained.
[0018]
(Examples 2 and 3)
Instead of the conductive paste mainly composed of Pt powder as the material constituting the unfired metal film, the conductive paste mainly composed of Ir powder is used in Example 2, and the weight ratio of Pt and Ir in Example 3 is used. The same procedure as in Example 1 was used except that a conductive paste containing 50 to 50 was used.
[0019]
(Comparative Example 1)
The conductive paste was the same as that of Example 1 except that a conductive paste containing Ag and Pd in a weight ratio of 30:70 was used instead of the paste mainly composed of Pt.
[0020]
(Evaluation of Examples 1 to 3 and Comparative Example 1)
In Examples 1 to 3, as shown in Table 1 below, the thin ceramic plate was easily separated from the metal film after ultrasonic treatment, and the thin ceramic plate could be easily taken out. On the other hand, in Comparative Example 1, the thin ceramic plate was not easily separated from the metal film made of Ag—Pd. The adhesion force between the thin ceramic plate and the metal film in the structure finally obtained in Comparative Example 1 was measured and found to be 98 MPa.
[0021]
When measuring the adhesion strength in Comparative Example 1, as shown in FIG. 2, the ceramic sintered body 21 was supported at three points A to C, and the bending strength was measured by a three-point bending strength test. That is, when the ceramic sintered body 21 is broken, separation occurs at the interface between the metal film and the thin ceramic plate. Therefore, the strength when the ceramic sintered body is broken is defined as an adhesive force (MPa).
[0022]
In Examples 1 to 3, since the thin ceramic plate was easily separated from the metal film, the adhesion force could not be measured.
In Examples 1 to 3, the thin-layer ceramic plate was easily separated from the metal film by ultrasonic treatment as described above, and the thin-layer ceramic plate was smooth and free from warpage. This is considered to be because the generation of warpage is suppressed in the obtained thin layer ceramic plate because the thin layer ceramic plate is supported by the metal film at the stage of obtaining the ceramic sintered body.
[0023]
[Table 1]

[0024]
(Example 4)
As starting materials, ceramic powders of Pb ₃ O ₄ , TiO ₂ , ZrO ₂ , NiO and Nb ₂ O ₅ were prepared. These ceramic powders are used to obtain ceramics having a composition of Pb _1.0 (Ni _1/2 Nb _1/2 ) O _2.0- (Zr _0.35 Ti _0.45 ) O ₃ . The ceramic powder was weighed, and a ceramic sintered body was obtained in the same manner as in Example 1. Also in Example 4, this ceramic sintered body was used, and vibration was given using an ultrasonic cleaner as in Example 1. As a result, the thin ceramic plate was separated from the metal film, and the thin ceramic plate could be easily taken out.
[0025]
(Examples 5 and 6)
As the conductive paste constituting the unsintered metal film, instead of the paste mainly composed of Pt, Example 5 is mainly composed of Ir powder, and in Example 6, Pt and Ir are mixed in a weight ratio of 50 pairs. A sintered body was obtained in the same manner as in Example 4 except that the conductive paste included in No. 50 was used, and ultrasonic treatment was performed in the same manner as in Example 4 to obtain a thin-layer ceramic plate.
[0026]
(Comparative Example 2)
A ceramic sintered body was obtained in the same manner as in Example 4 except that the conductive paste constituting the unsintered metal film was a paste containing Ag and Pd in a weight ratio of 30 to 70. Sonication was performed.
[0027]
(Evaluation of Examples 4 to 6 and Comparative Example 2)
As shown in Table 2 below, in Examples 4 to 6, the thin ceramic plate was well separated from the metal film by ultrasonic treatment, and the thin ceramic plate could be taken out. Therefore, the adhesion between the thin ceramic plate and the metal film could not be measured.
[0028]
On the other hand, in Comparative Example 2, the metal film was not peeled off from the thin ceramic plate, and the adhesion between them was measured to be 101 MPa.
In Examples 4 to 6, as in Example 1, a thin ceramic plate having a smooth surface and no warpage could be obtained.
[0029]
[Table 2]

[0030]
As is clear from the results of Examples 1 to 6, in the method for manufacturing a thin-layer ceramic plate according to the present invention, an unsintered metal film is configured using a metal composed of at least one of platinum and iridium. Therefore, the thin ceramic plate obtained by firing the ceramic green sheet is easily removed from the metal film by ultrasonic treatment of the ceramic sintered body. This is because, in the case of Ag—Pd alloy, Ag or Pd, the metal is firmly bonded to the ceramics through oxygen during firing, whereas Pt and Ir are weakly bound to oxygen. That is, since a metal film formed using a metal composed of at least one of Pt and Ir has a considerably low adhesive strength with ceramics, a thin ceramic plate can be formed only by applying vibration by ultrasonic treatment. Easily separated from.
[0031]
In Examples 1 to 6, Pb-based ceramics were used as the ceramic material constituting the thin ceramic plate, but other ceramics such as barium titanate-based ceramics may be used.
[0032]
【The invention's effect】
As described above, in the method for manufacturing a thin-layer ceramic plate according to the present invention, the unsintered metal film composed of a metal composed of at least one of platinum and iridium and the ceramic green sheets are alternately arranged. A laminated body is formed by laminating, and a sintered body is obtained by firing the laminated body. Accordingly, since the adhesion strength between the metal film composed of at least one of platinum and iridium and the thin ceramic plate obtained by firing the ceramic green sheet is low, an external force is applied by ultrasonic treatment or the like in the third step. As a result, the bonding between the metal film and the thin ceramic plate can be easily released. Therefore, the thin ceramic plate can be easily taken out only by applying an external force such as ultrasonic treatment.
[0033]
Further, since the sintered body is obtained by firing the laminated body, the thin layer ceramic plate in the sintered body is supported by the metal film, and thus the thin layer ceramic plate is thin. In addition, a thin ceramic plate with less warpage can be obtained. Therefore, according to the present invention, it is possible to stably supply a very thin ceramic plate having less warpage and excellent surface smoothness, for example, a thickness of 20 μm or less.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing a ceramic sintered body prepared in one embodiment of the present invention.
2 is a schematic front cross-sectional view for explaining a test method for evaluating the adhesion strength between a metal film and a ceramic plate in Comparative Example 1. FIG.
FIGS. 3A and 3B are views for explaining an example of a method for obtaining a conventional thin-layer ceramic plate, and FIG. 3A is a front sectional view showing a ceramic sintered body to be prepared; (B) is a schematic front sectional view showing a step of dissolving a metal film by electrolysis.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Ceramic sintered compact 2-4 ... Thin layer ceramic plate 5, 6 ... Metal film 21 ... Ceramic sintered compact (Comparative example 1)

Claims (2)

A first step of obtaining a laminate by alternately laminating ceramic green sheets and unsintered metal films formed of a conductive paste;
A second step of obtaining a sintered body obtained by integrating the metal film and the thin ceramic plate obtained by firing the ceramic green sheet by firing the laminate;
A third step of obtaining a thin layer ceramic plate by separating the metal film and the thin layer ceramic plate in the sintered body,
In the first step, the unsintered metal film is configured using a metal composed of at least one of platinum and iridium,
In the third step, the metal film and the thin ceramic plate in the sintered body are separated by applying an external force to the sintered body. The method for producing a thin ceramic plate according to claim 1, wherein in the third step, the external force is applied by applying vibration by ultrasonic treatment.

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