JP2004158516A - Electronic ceramic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic ceramic device which can be optionally arranged and easily mounted without taking specific orientations or parts into consideration when a wire is connected to an electrode. <P>SOLUTION: The electronic ceramic device, such as a thermistor or the like, is formed of electronic ceramic particles which are each equipped with a plurality of metal electrodes distributed like islands on its surface. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The invention of this application relates to an electronic ceramic device. More specifically, the invention of this application relates to various electronic ceramic devices including a thermistor that exhibits its function by being arranged between terminals on an electronic substrate.
[0002]
[Prior Art and Problems of the Invention]
2. Description of the Related Art Conventionally, an electronic ceramic device used for surface mounting generally has a rectangular parallelepiped shape, and has electrodes at both ends. When placing the electronic ceramic device between the terminals on the electronic substrate, the electronic ceramic device must be placed in the up, down, left, and right directions so that the electrodes at both ends are in contact with the terminals with the solder in between, and installed correctly. Melts and joins the solder with. Therefore, in general, a method is used in which the position and direction of the electronic ceramic device are determined in advance, and the electronic ceramic device is attached to a tape at an accurate pitch (taping method). According to the taping method, the electrodes are arranged in the same direction in advance, so that they can be mechanically arranged at predetermined positions between the electrodes.
[0003]
However, as electronic ceramic devices have become smaller and more highly integrated, it has been required to make connections to electronic ceramic devices having a size of about 100 μm. Since a process of accurately determining the direction and attaching the tape to the tape is essential, it has been difficult to reduce the size of the electronic ceramic device to about 1 mm or less. In addition, in order to shorten manufacturing time and reduce costs, an electronic ceramic device that eliminates the need for a pre-treatment step of determining the position and direction in advance and attaching the tape to the tape at an accurate pitch, and that does not generate waste due to the tape. The realization of the manufacture of was required.
[0004]
Therefore, the invention of this application has been made in view of the circumstances described above, and is easy to mount electronic components that can be arranged without considering a specific direction or site when connecting to electrodes. It is an object to provide a ceramic device.
[0005]
[Means for Solving the Problems]
The invention of this application solves the above-mentioned problems, and firstly, provides an electronic ceramic device comprising electronic ceramic particles having a plurality of metal electrodes distributed in an island shape on the surface.
[0006]
Secondly, the invention of the present application is directed to the above-mentioned electronic ceramic device, wherein, secondly, a metal electrode made of a metal having low wettability with respect to the electronic ceramic particles is closely adhered to the surface of the electronic ceramic particles by mechanical impact. Thirdly, the electronic ceramic particles are made of barium titanate semiconductor particles, and the metal electrode is made of a Pb-Sn eutectic solder containing 1 to 5% of Y. An electronic ceramic device is provided.
Fourth, the invention of this application is a method of mounting an electronic ceramic device on an electronic substrate, in which the metal electrodes of the electronic ceramic device are connected to metal terminals on the electronic substrate. An electronic ceramic device, wherein the electronic ceramic device is disposed between terminals on a substrate, and then the metal electrode and the metal terminal are connected by at least one of heating, discharging, or friction to the metal terminal. Provide an implementation method for.
Fifth, the invention of this application relates to a method of mounting an electronic ceramic device, characterized in that the melting point of a metal terminal is lower than the melting point of a metal electrode. Then, the electronic ceramic device is placed between the terminals on the electronic substrate, and then the metal electrode and the metal terminal are heated to a temperature intermediate between the melting points of the metal electrode and the metal terminal, thereby melting the metal terminal. And a method of mounting an electronic ceramic device, characterized by connecting a metal electrode and a metal terminal. Seventh, the metal terminal on the electronic substrate is made of a metal having low wettability to ceramic particles of the electronic ceramic device. It is intended to provide a mounting method of an electronic ceramic device characterized by the following.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention of this application has the features as described above, and embodiments thereof will be described below.
[0008]
The electronic ceramic device according to the invention of the present application includes electronic ceramic particles having a plurality of metal electrodes distributed on the surface in an island shape. The metal electrode is made of a metal having low wettability with respect to the electronic ceramic particles, and is firmly fixed to the surface of the electronic ceramic particles by mechanical impact.
[0009]
As the electronic ceramic particles constituting the electronic ceramic device of the invention of this application, various ceramic materials mainly including an electric resistance component such as PTC and NTC can be appropriately selected. Can be Further, as the metal electrode, various conductive soft metals having low wettability to the electronic ceramic particles can be appropriately selected, and for example, a Pb-Sn eutectic solder is used.
[0010]
The electronic ceramic device according to the invention of the present application is such that an electronic ceramic device is arranged between metal terminals on an electronic substrate, and then the metal electrode and the metal terminal are heated, discharged, or rubbed against the metal terminal. Is connected between the metal terminals on the electronic board. The melting point of the metal terminal is preferably lower than the melting point of the metal electrode. In this case, the electronic ceramic device is disposed between the terminals on the electronic substrate, and then the metal electrode and the metal terminal are separated from the melting point of the metal electrode. The metal terminal is heated to a temperature intermediate to the melting point of the metal terminal to melt the metal terminal, thereby connecting the metal electrode and the metal terminal. Further, as the metal terminal on the electronic substrate, a metal having low wettability with respect to the ceramic particles of the electronic ceramic device is used.
[0011]
That is, in the electronic ceramic device according to the invention of the present application, any two of a plurality of metal electrodes formed in advance in the form of islands on the surface of the electronic ceramic particles are connected to metal terminals. Thus, a function as an electronic ceramic device is exhibited. By disposing the metal electrodes appropriately in an island shape and arranging the particles between the terminals having a gap slightly smaller than the diameter of the particles, the metal electrodes always come into contact with the metal terminals.
[0012]
Since the electronic ceramic device of the invention of this application does not need to be arranged in a predetermined direction, it is necessary to pre-determine the position and direction in advance and stick it to the tape at an accurate pitch as in the conventional taping method. There are advantages such as no waste and no waste such as tape. Furthermore, in the taping method, it is difficult to reduce the size of the device to 1 mm or less due to the necessity of deciding the direction and affixing the tape to the tape. It is possible to disperse and form the necessary metal electrodes on the surface in an island shape, opening the way to miniaturization and high integration of devices. As a method of forming necessary metal electrodes in the form of island distribution on the surface of electronic ceramic particles up to about 100 μm, a proposal has already been made by the inventors of the present invention (see Patent Document 1).
[0013]
[Patent Document 1]
Japanese Patent Application No. 2001-288212 discloses a ball semiconductor in which a circuit is formed on a spherical silicon particle surface and is arranged on an appropriate substrate as a conventional technique in which a function is imparted to a particle and used alone as a device. I have. In a ball semiconductor, the size of the silicon particles is as large as about 1 mm in diameter, and the position and direction of the silicon particles need to be adjusted in order to join a specific terminal of the circuit on the ball surface and a predetermined terminal on the substrate. It needs to be determined precisely.
[0014]
In the field of the electronics industry, higher densification and higher integration are rapidly advancing, and mounting technology of devices is gaining importance. When miniaturizing a device, it is meaningless if the device is not large enough to be mounted, and in order to precisely determine the direction and position and arrange it, for example, the NTC thermistor has a minimum size of about 1 mm. I have. Since the present invention uses electronic ceramic particles in which metal electrodes distributed in an island shape are formed in advance, connection is possible simply by arranging them without deciding the direction. The precision arrangement of components can be performed with an accuracy of the order of several μm. In the electronic ceramic device of the present invention, miniaturization depends only on the size of the electronic ceramic particles. As described above, the technique proposed by the inventors of the present invention makes it possible to form metal electrodes distributed in an island shape on the surface of electronic ceramics having a particle size of 100 μm. It is expected that the device configuration according to the invention of the present invention will greatly promote higher density and higher integration of electronic equipment.
[0015]
The above is an example of the mode in the invention of this application, and it is needless to say that the invention of this application is not limited to these, and that various details can be taken in detail.
[0016]
The invention of this application has the above-mentioned features, and will be described in more detail with reference to examples below.
[0017]
【Example】
An electronic ceramic device according to the invention of the present application was manufactured using barium titanate semiconducting particles exhibiting PTCR characteristics sieved to 710 to 850 μm and solder particles sieved to 20 μm or less. Although the solder particles are eutectic solder of Pb-Sn, the melting point is increased by about 50 ° C. by adding several percent (for example, about 1 to 5%) of Y. These samples were weighed so as to have a weight ratio of 4: 1, charged in a cylindrical container having a diameter of 4 cm, and rotated and stirred at a rotation speed of 200 rpm for 3 hours by a ball mill. FIG. 1 shows an SEM image of the surface of the electronic ceramic device obtained by the rotation and stirring. From FIG. 1, it can be seen that solder particles acting as metal electrodes are dispersed and attached to the surface of the barium titanate semiconductor particles in the form of islands. The solder dispersed on the surface of the barium titanate particles is originally granular, but is mechanically stretched and fixed on the surface of the barium titanate particles by rotation and stirring.
[0018]
The electronic ceramic device made of barium titanate semiconducting particles exhibiting PTCR characteristics manufactured as described above was mounted on an electronic substrate as a single-particle PTC thermistor. FIG. 2 shows a schematic view of an electronic substrate on which an electronic ceramic device is mounted. FIG. 3 shows a photograph of the appearance of the electronic substrate on which the electronic ceramic device is mounted.
[0019]
As shown in FIGS. 2 and 3, on the circuit (3) on the surface of the electronic substrate (1), two metal terminals (4) having a center distance of 0.65 mm were formed by screen printing to have a melting point of about 180 ° C. The Pb-Sn eutectic solder was placed so as to be raised. When the electronic ceramic device (5) is arranged between the metal terminals (4) and then heated to 200 ° C. on a hot plate, the solder as the metal terminal (4) melts and is the metal electrode of the electronic ceramic device (5). Joined with solder.
[0020]
Generally, solder has low wettability to ceramics, and the molten solder is rounded on the ceramics and does not adhere even if solidified as it is. For this purpose, as described above, the metal electrode is brought into close contact with the surface of the ceramic particles by applying a mechanical impact. In the above-described soldering bonding in the present embodiment, since the solder on the barium titanate semiconductor particles does not melt, the adhesion with the barium titanate particles is maintained. On the other hand, the solder which is a metal terminal has low wettability with respect to barium titanate, so that it is repelled after being melted and joined only with the solder which is a metal electrode having high wettability.
[0021]
The electronic substrate was placed in a thermostat, the temperature was changed from room temperature to 140 ° C., and the resistance of the electronic ceramic device at each temperature was measured by a high-precision resistance meter. FIG. 4 shows the measurement results. From room temperature (approximately 30 ° C.) to 100 ° C., the resistance increased by two orders of magnitude, demonstrating that the electronic ceramic device of the present example exhibited characteristics as a PTC thermistor.
[0022]
【The invention's effect】
As described in detail above, the invention of this application provides an easily mountable electronic ceramic device that can be arranged without considering a specific direction or site when connecting to an electrode.
[0023]
Since it is not necessary to determine the direction when arranging the electronic ceramic particles, it is possible to easily mount the electronic ceramic particles on the electronic substrate, and further downsize the electronic ceramic device. The simplification of the mounting technology and the miniaturization of the device greatly contribute to the miniaturization and high-density of the electronic equipment. Therefore, the practical application of the invention of this application is expected.
[Brief description of the drawings]
FIG. 1 is an SEM image of a surface of an electronic ceramic device manufactured in an example of the present invention.
FIG. 2 is a schematic view showing an electronic substrate on which an electronic ceramic device manufactured in an embodiment of the present invention is mounted.
FIG. 3 is a photograph showing an electronic substrate on which an electronic ceramic device manufactured in an example of the present invention is mounted.
FIG. 4 is a graph showing the temperature dependence of resistance of an electronic ceramic device manufactured in an example of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electronic board 2 Terminal to external circuit 3 Circuit 4 Metal terminal 5 Electronic ceramic device

Claims (7)

An electronic ceramic device comprising electronic ceramic particles having a plurality of metal electrodes distributed in an island shape on the surface. 2. The electronic ceramic device according to claim 1, wherein a metal electrode made of a metal having low wettability with respect to the electronic ceramic particles is fixedly adhered to the surface of the electronic ceramic particles by mechanical impact. 3. The electronic ceramic device according to claim 1, wherein the electronic ceramic particles are made of semiconducting barium titanate particles, and the metal electrode is made of a Pb-Sn eutectic solder containing 1 to 5% of Y. 4. A method for mounting an electronic ceramic device on an electronic substrate, comprising connecting a metal electrode of the electronic ceramic device to a metal terminal on the electronic substrate, wherein the electronic ceramic device is arranged between terminals on the substrate. And then connecting the metal electrode and the metal terminal by at least one of heating, discharging, or friction to the metal terminal. 5. The method according to claim 4, wherein the melting point of the metal terminal is lower than the melting point of the metal electrode. The electronic ceramic device is placed between the terminals on the electronic substrate, and then the metal electrode and the metal terminal are heated to a temperature intermediate between the melting point of the metal electrode and the melting point of the metal terminal to melt the metal terminal. The method for mounting an electronic ceramic device according to claim 5, wherein the electrode and the metal terminal are connected. 7. The method for mounting an electronic ceramic device according to claim 4, wherein the metal terminal on the electronic substrate is made of a metal having low wettability to ceramic particles of the electronic ceramic device.

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