JPS62196811A - Ceramic substrate with built-in capacitor - 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 [Field of Industrial Application] The present invention relates to a multilayer ceramic substrate with a built-in multilayer capacitor. More specifically, the present invention relates to a multilayer ceramic substrate with a built-in multilayer capacitor having a terminal structure including through-hole conductors.

[Background Art] Recently, as electronic devices have become smaller, wiring boards have become smaller and more dense. Even in capacitor parts, which are an important element in electronic components, ceramic capacitors, which have relatively small capacitance, can be laminated to increase the capacitance value by starting from the disk type.

Furthermore, stacked components are progressing to capacitor blocks having multiple capacitance values in one capacitor chip. However, even the above-mentioned capacitor block needs to be mounted on a substrate, and there is a limit to its integration density. Therefore, recently, a capacitor-embedded ceramic substrate, in which a capacitor is built inside the ceramic substrate, is being developed.

However, with conventional ceramic substrates with built-in capacitors,
The ceramic that makes up the capacitor has a relatively high dielectric constant, and when forming a capacitor with a high capacitance, it is important to have a different capacitance depending on the size of the electrode area.
There are many problems, such as the fact that it is extremely difficult to form capacitors with significantly different capacitance values on the same substrate.

Recently, in order to solve one or more of the two problems, it has been considered to stack ceramics with different dielectric constants and fire them at the same time, but it is necessary to match the shrinkage rates of each other.
Very difficult.

[Problems to be Solved by the Invention] An object of the present invention is to eliminate two or more drawbacks of conventional ceramic substrates with built-in capacitors.

That is, the present invention is characterized in that: (1) at least one laminated ceramic body containing at least one individually sintered laminated capacitor and at least one thin, highly insulating, and low dielectric constant ceramic substrate are partially mutually connected; It is an object of the present invention to provide a capacitor-embedded ceramic substrate in which ceramic substrates having different shrinkage rates can be combined in a bonded configuration, and multilayer capacitors having significantly different capacitance values can be formed within the same substrate.

[Means for Solving the Problems] The present invention provides at least one capacitor having at least one capacitor function, which is constructed by laminating an inner conductor layer and a dielectric weight.
This ceramic substrate has a built-in multilayer capacitor, in which two multilayer ceramic bodies and at least one highly insulating thin ceramic substrate are bonded together. The laminated ceramic body has one through hole or a hole that penetrates to the lowest conductor layer, the internal electrode and the terminal electrode are electrically connected to each other by a conductive paste filled in the hole, and a capacitor terminal is provided on the upper surface of the laminated ceramic body. Since the capacitor is electrically connected to the upper surface of the ceramic substrate having through holes provided at arbitrary positions, both terminals of the capacitor can be provided at arbitrary positions on the uppermost surface. The above-mentioned bonding is carried out by firing at least one of solder, glass, and thick-film conductor paste on a portion of the surface of the laminated ceramic body and thin-film ceramic substrate after individually firing the laminated ceramic body and the thin-film ceramic substrate. It can be done using The other surface parts are made of laminated ceramic/resistance or thin film ceramic/resistance substrates with air between them! 5(
voids) can be made to exist.

The 'gtWI capacitor built-in ceramic substrate 1 of the present invention has a structure such as, for example, No. 8 IyJ, and is composed of a multilayer ceramic body 21, 22 containing a multilayer capacitor and a thin ceramic substrate 9, with a gap 10 provided therebetween, and a predetermined It has a structure in which joints are provided at the locations and they are joined to each other.

That is, ceramic bodies 21 and 2 containing multilayer capacitors
The ceramic dielectrics constituting 2 are manufactured separately, i.e.
Since it can be fired completely, no problem occurs even if the shrinkage rate etc. differ significantly during the firing process.

This is a laminated ceramic body that constitutes one of the present inventions.

This is because the ceramic substrates are bonded with a distance between them, so that the effects of differences in shrinkage and expansion coefficients between the ceramic substrates are eliminated. That is, only a portion of the surface of the laminated ceramic body or ceramic substrate is provided with a joint portion using solder, glass, or thick film conductive paste. In the actual manufacturing method, at least one of the above bonding agents is applied to the predetermined locations on the surfaces of the laminated ceramic body and ceramic substrate to be bonded.
The two pieces are placed using a screen printing technique or the like to form a bump-like product, which is then assembled (for example, as shown in FIG. 7) and fired at a relatively low temperature in a rib-blow oven or the like. As a result, the laminated ceramic body and the ceramic substrate are bonded to each other by melting their bump-like parts, and are bonded to each other with a gap, that is, an air layer, to form a structure of the present invention. can.

That is, in the multilayer capacitor-embedded ceramic v-shaped substrate of the present invention, the ceramic body containing each multilayer capacitor is separately produced by firing. Therefore, each ceramic body with a built-in multilayer capacitor may be made of ceramic dielectric materials having completely different physical properties 9, for example, significantly different shrinkage rates and dielectric constants, and these can be bonded according to the present invention.

Furthermore, the ceramic substrate with a built-in multilayer capacitor of the present invention has a structure that includes a ceramic substrate having a desired circuit pattern on its upper surface, and allows easy conduction with the built-in multilayer capacitor. That is, in the structure of the present invention shown in FIG.
Conductor and resistance pattern 1 on the surface of thin ceramic substrate 9
6 is formed of a conductive paste or the like as shown in the figure, and a hybrid integrated circuit ceramic substrate having a desired circuit is obtained.

Therefore, the ceramic substrate with a built-in multilayer capacitor according to the present invention can have a small overall thickness, and can easily conduct electrical connections between a plurality of multilayer capacitors. Also.

The hole that conducts the built-in capacitor can be set at any location.1
There is also a large degree of freedom in circuit pattern design.

Materials that can be used to form conductor patterns and conductors include gold, ffi, copper, platinum, and palladium.

It is a conductive metal such as molybdenum or tungsten, and its paste can be printed on the top surface of a ceramic substrate by screen printing or the like to form a conductor layer or through-hole conductor.

Materials used for forming the joint portion of the present invention include solder, glass, thick film conductor paste, and the like, which can be melted at a relatively low temperature and can be joined. A laminated ceramic body containing a built-in capacitor during firing to form a joint for bonding.

In order not to damage the thin-film ceramic substrate containing the circuit pattern, it is best to fire at a temperature as low as possible, preferably at 900°C.
Use materials that can be bonded at the following firing temperatures. The firing temperature for bonding is preferably about 500°C to 600°C. Glass bonding is used in locations where electrically conductive bonding parts are not required.

The ceramic dielectric material used in the present invention is:

A material commonly used for ceramic substrates with built-in multilayer capacitors, such as alumina, may be used, but by appropriately selecting the dielectric constant, a desired capacitance value of the multilayer capacitor can be obtained. That is, desired circuit characteristics can be obtained by freely using a combination of ceramic dielectric materials having a low dielectric constant and ceramic dielectric materials having a high dielectric constant. Therefore, the ceramic substrate,
Other materials that can be used to sandwich the multilayer capacitor include substrate materials with a low dielectric constant, materials with a high dielectric constant such as Bao-riot, and titania (TtO*)-based substrate materials.

The capacitor built-in ceramic substrate obtained by the present invention can be used, for example, as a multilayer wiring board for hybrid integrated circuits used in electronic devices and the like. For example, among the four capacitors C1 to C4 shown in FIG. 1 used for manufacturing and assembling the circuit shown in FIG. 1, C1 and C1 have relatively low capacitance values, and C+ and C4 have relatively high capacitance values. The present invention is used to fabricate a ceramic substrate in which capacitors having significantly different capacitance values are built into the same substrate.

Next, a ceramic substrate with a built-in multilayer capacitor according to the present invention will be described, but the present invention is not limited to the first embodiment.

[Example] The structure and assembly procedure of a ceramic substrate with a built-in multilayer capacitor according to the present invention will be explained with reference to the drawings. 2 and 3 show the assembly of a ceramic body with a built-in capacitor having a low capacitance value, and FIGS. 4 and 5 show the assembly of a ceramic body with a built-in capacitor having a high capacitance value.

7 and 8 show the structure and assembly of multilayer capacitors having significantly different capacitance values according to the present invention.

That is, the second image is a plan view and a sectional view showing a ceramic body with a built-in capacitor in which a dielectric 1 having a relatively low dielectric constant and electrodes 2 and 3 facing each other are laminated inside and fired.

FIG. 3 shows a through hole or a hole 14 provided in the multilayer capacitor built-in ceramic body shown in FIG. After establishing continuity, a conductor pattern 4 is printed and installed on the top surface of the ceramic body with a built-in multilayer capacitor. This through-hole conductor 14 and the conductor pattern (:
The conductor terminal (4) is formed by printing a conductive paste such as silver-palladium paste on the surface of the ceramic body with a built-in multilayer capacitor shown in FIG. 2 using a screen printing technique, thereby filling the holes with a conductor.

A pattern of terminals can be formed on the surface of the ceramic body.

FIG. 4 shows that due to the dielectric material 5 having a relatively high dielectric constant,
mutually opposing capacitor electrodes 6.7 are stacked on each other;
FIG. 2 is a plan view and a cross-sectional view showing a ceramic body with a built-in multilayer capacitor produced by firing.

FIG. 5 shows a ceramic body containing a multilayer capacitor with a relatively high capacitance value as shown in FIG.
7 and the top surface, a conductor pattern 8 is printed and installed on the top surface of the ceramic body with a built-in multilayer capacitor. Providing a conductor in this hole and forming a conductor pattern on the top surface of the ceramic body can be similarly made by passing a conductive paste as in the case of FIG.

In FIG. 6, through holes 11 are provided in a highly insulating and low dielectric constant ceramic substrate 9 having a thickness of 150 μm or less. This ceramic substrate 9 is preferably an alumina substrate that can be manufactured by a sol-gel method using metal alkoxide as a starting material, and in practice, ceramic substrates with a thickness of 30/Zm have now been realized.

FIG. 7 shows a ceramic body 21 with a built-in multilayer capacitor shown in FIG. 3 and a ceramic body 22 with a built-in multilayer capacitor shown in FIG.
A thin ceramic substrate having through-holes as shown in FIG. It is assembled so that it is joined only at the parts. This bonding is performed by forming a bonding convex portion at a predetermined position using a thick film forming technique using a screen printing technique using a bonding paste such as 2 or more, and then assembling such a ceramic substrate as shown in FIG. 9 and placing it in a furnace. , firing, melting the bonding paste, etc.

FIG. 8 shows a completed circuit in which a conductor and resistance pattern 16 is printed on the top surface of the ceramic substrate with a built-in multilayer capacitor shown in FIG. 7, and a device chip, for example, a transistor 18 is mounted. The equivalent circuit shown in Figure 1 was completed.

[Effects of the Invention] The ceramic substrate with a built-in multilayer capacitor of the present invention has the above-described structure, so that, firstly, two or more dielectrics having different permittivity can be used in the same ceramic substrate with a built-in multilayer capacitor. Second, it has become possible to form two or more types of multilayer capacitors with significantly different capacitance values on the same ceramic substrate with a built-in capacitor. Third, the electrodes of the built-in multilayer capacitor can now be formed on the same ceramic substrate. Fourth, the coupling between the top surface conductor and the electrodes inside the plurality of laminates can be kept small.
Second, a part of the crossover can be easily installed, increasing the degree of freedom in design.Fifth, the capacitor terminals provided on the top surface of the ceramic substrate with built-in multilayer capacitors can be printed with a conductor pattern on the bonding surface. Sixth, the position can be designed relatively freely; and sixth, the dielectric material forming the multilayer capacitor can have a very high dielectric constant.

[Brief explanation of drawings]

FIG. 1 shows an example of a circuit assembled on a ceramic substrate with a built-in multilayer capacitor according to the present invention. FIG. 2 is a plan view and a sectional view showing an example of a ceramic body with a built-in stacking capacitor used in the present invention. FIG. 3 shows the laminated ceramic body of FIG. 2 provided with conductor holes and conductor patterns for electrical continuity. FIG. 4 is a plan view and a sectional view showing an example of a ceramic body with a built-in laminated condenser made of two ceramics having a high dielectric constant used in the present invention. FIG. 5 shows the laminated ceramic body of FIG. 4 provided with holes and conductive patterns for conduction. FIG. 6 is a plan view and a cross-sectional view of a thin ceramic substrate provided with through holes. FIG. 7 is a plan view showing the structure of a multilayer capacitor built-in ceramic/substrate of the present invention in which the multilayer ceramic body of FIG. 3, the multilayer ceramic body of FIG. 5, and the ceramic substrate of FIG. 6 are assembled; FIG. FIG. 8 shows a ceramic substrate with a built-in multilayer capacitor shown in FIG. 7 provided with conductor holes and conductor (circuit) patterns for electrical connection. [Explanation of symbols of main parts] 110. Ceramic body with low dielectric constant 2.3, 6, 7. ,,, Multilayer capacitor electrode (conductor layer) 4.8. , , , Conductor pattern (terminal) 513. High dielectric constant ceramic body 90. ．． Thin ceramic substrate 10,...Space layer (air layer) 11,...Through holes 14.15.17. ,,Through conduction hole 16, ,Top conductor (resistance) pattern 1B, ,Transistor mounting position Patent applicant Mitsubishi Mining Cement Co., Ltd. Agent Patent attorney Hiroshi Kuramochi Commissioner of the Patent Office Michibe Uga 1.9s Display of the matter Patent Application No. 036531 of 1985 2, Name of the invention Ceramic substrate with built-in capacitor 3, Person making the amendment Relationship to the case Applicant address 5-1 Marunouchi-chome, Chiyoda-ku, Tokyo Mitsubishi Mining Cement Co., Ltd. Representative Hisaaki Kobayashi 4, Agent Address: 11-15, Ichiban-cho, Chiyoda-ku, Tokyo 102 Number of inventions increased by the amendment 07 Contents of the amendment (1) As shown in the appendix [Claims of claims are to be corrected] . (2) The 9th line on page 4 of the specification is corrected to ``combined''. (3) "Thin film ceramics" in page 5, line 8, lines 9 to 10, and line 13 of page 5 of the specification is corrected to "thin ceramic." Scope of Claims [( 1) It has a structure in which at least one laminated ceramic body having at least one capacitor function, which is constructed by laminating an internal conductor layer and a dielectric layer, and at least one thin ceramic substrate with high insulation are joined. A ceramic substrate with a built-in multilayer capacitor. (2) The multilayer ceramic body has one through hole or a hole that penetrates to the lowest conductor layer, and the conductor paste filled in the hole allows the upper surface of the laminated ceramic body to be A patent claim characterized in that a capacitor terminal is provided, and both terminals of the capacitor are provided at an arbitrary position on the uppermost surface by connecting the capacitor terminal with a terminal on the upper surface of the ceramic substrate through a through-hole conductor provided in the ceramic substrate at an arbitrary position. A ceramic substrate with a built-in capacitor according to scope 1. (3) The above bonding is performed by firing the two individual laminated ceramic bodies and the ceramic substrate separately, and then bonding the laminated ceramic body and b'+'yiヱ' ) Apply a small amount of solder, glass, or thick film conductor paste to a predetermined location on the surface of the board (in two rows, placing one of them in two rows, and place a laminated ceramic body on the other surface area, and apply 222y') to each other on the board. A ceramic substrate with a built-in multilayer capacitor according to claim 1, characterized in that there is an air space therebetween.]

Claims (3)

[Claims] (1) It has a structure in which at least one laminated ceramic body having at least one capacitor function, which is constructed by laminating an internal conductor layer and a dielectric layer, and at least one thin ceramic substrate with high insulation properties are bonded. Features a ceramic substrate with a built-in multilayer capacitor. (2) The laminated ceramic body has a through hole or a hole that penetrates to the lowest conductor layer, and a capacitor terminal is provided on the upper surface of the laminated ceramic body using a conductive paste filled in the hole, and a capacitor terminal is provided at an arbitrary position. The capacitor built-in ceramic according to claim 1, characterized in that both terminals of the capacitor are provided at arbitrary positions on the uppermost surface by conducting with the terminals on the upper surface of the ceramic substrate through a through-hole conductor provided in the ceramic substrate. substrate. (3) The above-mentioned bonding is performed by individually firing the laminated ceramic body and the ceramic substrate, and then applying solder or the like to predetermined locations on the surfaces of the laminated ceramic body and the thin-film ceramic substrate.
Claim 1, characterized in that at least one of glass and thick-film conductor paste is placed thereon, and there is an air layer between the laminated ceramic body and the thin-film ceramic substrate on the other surface portions. Ceramic substrate with built-in multilayer capacitor as described.