JP3834632B2 - Electronic ceramic device - Google Patents

Description

[0001]
BACKGROUND 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]
Conventionally, an electronic ceramic device used for surface mounting is generally a rectangular parallelepiped and has electrodes at both ends thereof. And when placing the electronic ceramic device between the terminals on the electronic substrate, the electronic ceramic device should be installed accurately with the vertical and horizontal directions determined so that the electrodes on both ends are in contact with the terminals with the solder sandwiched between them, reflow, etc. To melt and join the solder. For this reason, generally, a method (taping method) in which the position and direction of the electronic ceramic device are determined in advance and the electronic ceramic device is attached to the tape at an accurate pitch is used. According to the taping method, since the directions are aligned in advance, they can be mechanically arranged at predetermined positions between the electrodes.
[0003]
However, as electronic ceramic devices have been downsized and highly integrated, it is required to connect to electronic ceramic devices having a size of about 100 μm. Since the process of accurately determining the direction and attaching it 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 reduce manufacturing time and cost, an electronic ceramic device that can omit the pre-treatment process that determines the position and direction in advance and attaches to the tape at an accurate pitch, and does not generate waste from the tape. Realization of the production of was demanded.
[0004]
Accordingly, the invention of this application has been made in view of the circumstances as described above, and can be easily mounted on an electronic device that can be arranged without considering a specific direction or part when connecting to an electrode. It is an object to provide a ceramic device.
[0005]
[Means for Solving the Problems]
The invention of this application, as to solve the above problem, the first, Ri Do from electronic ceramic particles having a plurality of metal electrodes that are distributed like islands on the surface, the electronic ceramic particles
There is provided an electronic ceramic device characterized in that a metal electrode made of a metal having low wettability is adhered and fixed to the surface of an electronic ceramic particle by mechanical impact .
[0006]
The invention of this application, in the above-mentioned electronic ceramic device, the second, electronic ceramic particles consist semiconductive barium titanate particles, Pb-Sn eutectic solder metal electrode was added 1-5% of Y An electronic ceramic device characterized by comprising:
Further, the invention of this application, the third, on the electronic board, a mounting method of electronic ceramic device for connecting the metal electrodes of the electronic ceramic devices described above is the invention of this application to the metal terminals on the electronic substrate An electronic ceramic device is disposed between metal terminals on an electronic 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. A method for mounting a ceramic device is provided.
Further, as an invention is a mounting method of the above electronic ceramic device of this application, the fourth, the melting point of the metal terminal, the mounting method of the electronic ceramic device, characterized in that below the melting point of the metal electrode, the fifth Next, the electronic ceramic device is placed between the metal 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 of mounting an electronic ceramic device characterized in that the metal electrode and the metal terminal are connected to each other. Sixth , the metal terminal on the electronic substrate is made of a metal having low wettability to the electronic ceramic particles of the electronic ceramic device. that provides implementation of electronic ceramic device according to claim made.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The invention of this application has the features as described above, and an embodiment thereof will be described below.
[0008]
The electronic ceramic device according to the invention of this application is composed of electronic ceramic particles having a plurality of metal electrodes distributed in an island shape on the surface. The metal electrode is made of a metal having low wettability to the electronic ceramic particles, and is adhered and fixed to the surface of the electronic ceramic particles by mechanical impact.
[0009]
As the electronic ceramic particles constituting the electronic ceramic device according to the invention of this application, various ceramic materials mainly composed of electrical resistance components such as PTC and NTC can be appropriately selected. For example, semiconducting barium titanate particles are used. It is done. In addition, various conductive soft metals having low wettability with respect to the electronic ceramic particles can be appropriately selected as the metal electrode. For example, Pb—Sn eutectic solder is used.
[0010]
The electronic ceramic device according to the present invention is an electronic ceramic device in which an electronic ceramic device is disposed between metal terminals on an electronic substrate, and then the metal electrode and the metal terminal are subjected to at least one of heating, discharging, or friction with respect to the metal terminal. Are connected between the metal terminals on the electronic substrate. 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 connected to the melting point of the metal electrode. The metal electrode and the metal terminal are connected by heating to a temperature intermediate between the melting point of the metal terminal and melting the metal terminal. Moreover, the metal terminal on an electronic substrate uses the metal with low wettability with respect to the ceramic particle of an electronic ceramic device.
[0011]
That is, in the electronic ceramic device according to the invention of this application, any two of a plurality of metal electrodes formed so as to be distributed in an island shape on the surface of the electronic ceramic particles are connected to the metal terminal. As a result, the function as an electronic ceramic device is exhibited. By forming the metal electrodes in an appropriate island shape and arranging the particles between terminals having a gap slightly smaller than the diameter of the particles, the metal electrodes and the metal terminals are always in contact with each other.
[0012]
Since the electronic ceramic device according to the invention of this application does not need to be arranged in a specific direction, pre-processing is required in which the position and direction are determined in advance and pasted on the tape at an accurate pitch as in the conventional taping method. There is an advantage that there is no waste such as tape. Furthermore, in the taping method, it was difficult to set the size of the device to 1 mm or less due to the necessity of determining the direction and attaching it to the tape. It is possible to form the necessary metal electrodes distributed on the surface in an island shape, which opens the way to miniaturization and high integration of devices. As a method of forming the necessary metal electrodes distributed on the surface of the electronic ceramic particles up to about 100 μm in an island shape, the inventors of the invention of this application have already been proposed (see Patent Document 1).
[0013]
[Patent Document 1]
Japanese Patent Application No. 2001-288212 Particle semiconductors are known as a conventional technology that uses a single device as a device. A ball semiconductor is known in which a circuit is formed on the surface of a spherical silicon particle and placed on a suitable substrate. Yes. In ball semiconductors, the size of the silicon particles is as large as about 1 mm in diameter, and the position and direction of the semiconductor particles are determined when they are placed in order to join a specific terminal of the circuit on the ball surface and a predetermined terminal on the substrate. It is necessary to decide precisely.
[0014]
In the field of the electronic industry, high density and high integration are rapidly progressing, and device mounting technology is becoming more important. When miniaturizing a device, it is meaningless if the device is not of a size that can be mounted. For example, an NTC thermistor has a minimum size of about 1 mm in order to determine the direction and position precisely. Yes. Since the present invention uses electronic ceramic particles in which metal electrodes distributed in an island shape in advance are used, connection can be achieved simply by arranging them without deciding the direction. The precise arrangement of the components can be performed with an accuracy of the order of several μm. In the electronic ceramic device of the invention of this application, the miniaturization depends only on the size of the electronic ceramic particles. As described above, it is possible to form island-distributed metal electrodes on the surface of an electronic ceramic having a particle size of 100 μm by the method proposed by the inventors of the present invention. With the configuration of the device according to the present invention, it is expected that the density and integration of electronic equipment will be greatly promoted.
[0015]
The above is one example of the form of the invention of this application, and it goes without saying that the invention of this application is not limited to these, and that various details can be taken.
[0016]
The invention of this application has the above-described features, and will be described more specifically with reference to examples.
[0017]
【Example】
Using the semiconducting barium titanate particles exhibiting PTCR characteristics sieved to 710 to 850 μm and the solder particles sieved to 20 μm or less, an electronic ceramic device according to the invention of this application was produced. The solder particles are Pb—Sn eutectic solder, but by adding a few percent (for example, about 1 to 5%) of Y, the melting point is increased by about 50 ° C. These samples were weighed to a weight ratio of 4: 1, charged into a cylindrical container having a diameter of 4 cm, and rotated and stirred for 3 hours at a rotation speed of 200 rpm with a ball mill apparatus. The SEM image on the surface of the electronic ceramic device obtained by this rotation and stirring is shown in FIG. From FIG. 1, it can be seen that solder particles acting as metal electrodes are dispersed and adhered to the surface of the semiconducting barium titanate particles. The solder dispersed on the surface of the semiconducting barium titanate particles was originally granular, but was mechanically stretched and fixed on the surface of the semiconducting barium titanate particles by rotation and stirring.
[0018]
The electronic ceramic device made of semiconducting barium titanate particles exhibiting PTCR characteristics produced as described above was mounted on an electronic substrate as a single particle PTC thermistor. FIG. 2 shows a schematic diagram of an electronic substrate on which the electronic ceramic device is mounted. Moreover, the external appearance photograph of the electronic substrate with which the electronic ceramic device was mounted is shown in FIG.
[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 interval of 0.65 mm have a melting point of about 180 ° C. by screen printing. A Pb—Sn eutectic solder was placed so as to rise. When the electronic ceramic device (5) is placed between the metal terminals (4) and then heated to 200 ° C. with a hot plate, the solder as the metal terminals (4) is melted to form the metal electrodes of the electronic ceramic device (5). Joined with solder.
[0020]
In general, the wettability of the solder to the ceramic is low, and the molten solder becomes round on the ceramic and does not adhere even if it is solidified as it is. Therefore, as described above, the metal electrode is adhered and fixed to the surface of the ceramic particle by applying a mechanical impact. In the soldering joining in the present embodiment described above, the solder on the semiconducting barium titanate particles does not melt, so that the adhesion with the barium titanate particles is maintained. On the other hand, since the solder which is a metal terminal has low wettability with respect to barium titanate, it is repelled after melting and joined only with the solder which is a metal electrode having high wettability.
[0021]
This 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 with a high-precision resistance meter. FIG. 4 shows the measurement results. Between room temperature (about 30 ° C.) and 100 ° C., the resistance increased by two orders of magnitude, demonstrating that the electronic ceramic device of this 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 part when connecting to an electrode.
[0023]
When the electronic ceramic particles are arranged, it is not necessary to determine the directivity, so that mounting on the electronic substrate can be easily performed, and further downsizing of the electronic ceramic device is promoted. 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 strongly expected.
[Brief description of the drawings]
FIG. 1 is an SEM image of the surface of an electronic ceramic device produced in an example of the invention of this application.
FIG. 2 is a schematic view showing an electronic substrate on which an electronic ceramic device manufactured in an embodiment of the invention of this application is mounted.
FIG. 3 is a photograph showing an electronic substrate on which an electronic ceramic device manufactured in an example of the invention of this application is mounted.
FIG. 4 is a graph showing the temperature dependence of resistance of an electronic ceramic device manufactured in an example of the invention of this application.
[Explanation of symbols]
1 Electronic board 2 Terminal to external circuit 3 Circuit 4 Metal terminal 5 Electronic ceramics device

Claims (6)

Ri Do from electronic ceramic particles having a plurality of metal electrodes that are distributed like islands on the surface, sticking a metal electrode made of low wettability metal to the electron ceramic particles in close contact by mechanical impact to the electronic ceramic particle surface An electronic ceramic device characterized by being made . 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 to which 1 to 5% of Y is added . An electronic ceramic device mounting method for connecting a metal electrode of an electronic ceramic device according to claim 1 or 2 to a metal terminal on the electronic substrate on the electronic substrate, wherein the electronic ceramic device is disposed between the metal terminals on the electronic substrate. And mounting the metal electrode and the metal terminal by at least one of heating, discharging, or friction with respect to the metal terminal . 4. The method for mounting an electronic ceramic device according to claim 3 , wherein the melting point of the metal terminal is lower than the melting point of the metal electrode . By placing the electronic ceramic device between the metal terminals on the electronic substrate, and then heating the metal electrode and the metal terminal to a temperature intermediate between the melting point of the metal electrode and the melting point of the metal terminal, The method for mounting an electronic ceramic device according to claim 4, wherein the metal electrode and the metal terminal are connected . Metal terminals on the electronic board, a mounting method of electronic ceramic device according to any one of claims 3 to 5 wettability to electronic ceramic particles electronic ceramic device is characterized in that it consists of low metal.

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