JPH05259529A - Insulating substrate and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To provide the title insulating substrate forming through electrodes completely stopping up through holes without entailing cost up as well as the manufacturing method thereof. CONSTITUTION:Through electrodes 3 are formed by filling up through holes 2 with the first metallic powder 3A in the particle diameter of 10-90% of the diameter of the through holes 2 e.g. exceeding one particle, the second metallic powder 3B in the particle diameter smaller than that of the first metallic powder 3A e.g. multiple particles as well as glass powder 3C to be sintered later. In such a constitution, a conductive paste blended with a solvent, resin, etc., is not to be used for the metallic powder different from any conventional metallic powder so that the contraction of the metallic powder may be restrained during the sintering step and thereby the through electrodes 3 completely stopping up the through holes enabled to be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating substrate for forming a Hall element or the like used for detecting magnetism such as a rotor magnetic pole position of a brushless motor, and a method of manufacturing the same.

[0002]

2. Description of the Related Art When this type of Hall element is used in a brushless motor, the Hall element itself is flattened in order to meet the demand for flattening the brushless motor in a short axial direction. FIG. 7 shows an insulating substrate for forming such a flattened Hall element. In FIG. 7, reference numeral 11 denotes a rectangular insulating substrate made of ceramic, glass, or the like, and through holes 12 penetrating in the front-back direction are provided near the four corners of the insulating substrate 11. A conductive through electrode 13 is provided in the through hole 12,
The upper and lower end surfaces are exposed so as to be the same as the front and back surfaces of the insulating substrate 11.

On the surface of the insulating substrate 11, a thin magnetic film 14 having a Hall effect such as indium antimony is formed, and a conductive film 15 connecting the magnetic film 14 and the through electrode 13 is formed. These magnetic sensitive film 14 and conductive film 15
A protective film 16 is formed to cover the. On the other hand, an electrode portion 17 is formed on the end surface of the through electrode 13 exposed on the back surface of the insulating substrate 11, and on the surface of the electrode portion 17, solder bumps for connecting to a pattern or the like of an external wiring board not shown. 18 is formed. A protective coating portion 19 made of epoxy resin or the like is provided on the surface side of the insulating substrate 11 including the protective film 16.

In the insulating substrate 11 forming such a Hall element, in order to output a large Hall voltage, it is necessary to minimize the electric resistance between the magneto-sensitive film 14 and the electrode section 17. For this purpose, the through electrode 1
3 is formed so as to completely close the through hole 12. Here, the through electrode 13 is formed by filling the inside of the through hole 13 with a conductive paste prepared by mixing a metal powder with a solvent, resin, glass powder or the like, and then heating the insulating substrate 11 to sinter the metal powder. Is performed.

[0005]

By the way, in the conventional insulating substrate, since the volume of the conductive paste filled in the through holes shrinks during the sintering process, it is preferable to form the through electrodes so as to completely close the through holes. The problem is that it is impossible.

This is because the metal powder used generally has a fine particle size of 1 .mu.m or less, so that shrinkage proceeds during the sintering process. In order to eliminate such a defect, it is necessary to fill the through holes with the conductive paste several times and repeat the sintering process, which inevitably leads to an increase in cost.

The present invention has been made in consideration of the above problems, and provides an insulating substrate in which a through electrode is formed so as to completely close a through hole without increasing the cost, and a manufacturing method thereof. It is intended.

[0008]

In order to achieve the above object, the insulating substrate of the present invention has a conductive through electrode in a through hole penetrating in the front and back direction, and the through electrode is a metal powder sintered body. In an insulating substrate formed of a body, the through electrode has a first metal powder having a particle diameter of 10 to 90% of the diameter of the through hole, and a second metal having a particle diameter smaller than the first metal powder. It is characterized by being formed from powder and glass powder.

The insulating substrate of the present invention has at least 1
It is characterized in that it is formed from a first metal powder having a grain size or more, a second metal powder having a plurality of grains, and a glass powder.

Further, the method of manufacturing an insulating substrate of the present invention is
(A) At least one or more first metal powders having a grain size of 10 to 90% of the diameter of the through holes of the insulating substrate and a plurality of second metal grains having a grain size smaller than that of the first metal powders A powder and a plurality of glass powders having a particle size smaller than that of the first metal powder in the through hole; and (b) heating the insulating substrate to form the first metal powder and the second metal powder. At least the step of sintering the metal powder and the glass powder described above and (c) the step of planarly polishing the front and back surfaces of the insulating substrate.

[0011]

According to the insulating substrate of the present invention, the through electrode has, for example, one or more first particles having a particle diameter of 10 to 90% of the diameter of the through hole.
Of the second metal powder and a glass powder having a smaller particle size than the first metal powder and a plurality of second metal powders and a glass powder. Shrinkage of volume is suppressed during binding treatment. Therefore, the through hole can be completely closed.

According to the method for manufacturing an insulating substrate of the present invention, the first metal powder, the second metal powder, and the glass powder are filled in the through holes and then sintered and flattened. By mixing and melting the above metal powder, the second metal powder, and the glass powder, it is possible to form a through electrode that completely closes the inside of the through hole, and the upper and lower end surfaces of the through electrode can be insulated from each other. It can be the same as the front and back surfaces of.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a sectional view and a perspective view showing an embodiment of an insulating substrate of the present invention. Reference numeral 1 is a rectangular insulating substrate made of ceramic or glass, 2 is a through hole provided in the vicinity of four corners of the insulating substrate 1 so as to penetrate in the front and back directions, and 3 is a through electrode provided in the through hole 2. The end faces of the through electrode 3 are exposed so as to be the same as the front and back faces of the insulating substrate 1.

Here, the through electrode 3 has, for example, one or more first metal powders 3A having a particle size of 10 to 90% of the diameter of the through hole 2 and particles more than the first metal powder 3A. For example, a plurality of second metal powders having a small diameter and a glass powder having a smaller particle diameter than the first metal powder are sintered and formed. As the metal powder, gold, silver, copper, silver-palladium alloy, or the like, or a conductive material obtained by plating copper with silver is used.

Reference numeral 4 is a thin film-shaped magnetosensitive film having a Hall effect, such as indium antimony, formed on the surface of the insulating substrate 1, and 5 is a conductive film for connecting the magnetosensitive film 4 and the through electrode 3.
Is a protective film that covers the magnetic sensitive film 4 and the conductive film 5.
Reference numeral 7 denotes an electrode portion formed on the end surface of the through electrode 3 exposed on the back surface of the insulating substrate 1, reference numeral 8 denotes a solder bump formed on the surface of the electrode portion 7 for connecting to a pattern or the like of an external wiring substrate (not shown), Reference numeral 9 denotes a protective coating portion made of epoxy resin or the like provided on the front surface side of the insulating substrate 1 including the protective film 5. The protective coating portion 9 is provided to enhance the reliability of the Hall element formed on the insulating substrate 1, and improves the moisture resistance and at the same time the mechanical strength.

Next, a method of manufacturing an insulating substrate according to the present invention for manufacturing such an insulating substrate 1 will be described step by step. First, as shown in FIG. 3, a rectangular insulating substrate 1 made of ceramic, glass or the like having through holes 2 provided at its four corners in advance is prepared. Next, as shown in FIG.
The first metal powder 3A having a particle size of 10 to 90% of the diameter of the first metal powder 3A, and the second metal powder 3B having a particle size smaller than the first metal powder 3A, such as a plurality of particles. 1 glass powder 3C having a smaller particle size than the metal powder 3A. These metal powders can be filled by first filling the first metal powder 3A having a large particle size and then filling the second metal powder 3B having a small particle size and the glass powder 3C having a small particle size, or in advance. A method of filling the mixed first and second metal powders and glass powder can be used. As an example, when the mixed powder is spread on the surface of the insulating substrate 1 and pressed by a rubber roller or the like to fill the inside of the through hole 2, the metal powder can be filled in a well-filled state. In this case, the excess metal powder and glass powder should be removed with a spatula or the like.

Next, as shown in FIG. 5, the insulating substrate 1 is heated to heat the first and second metal powders 3A and 3B.
And glass powder 3C are melt-bonded and sintered. In this case, the atmosphere of heat treatment is changed depending on the type of metal powder. For example, when copper metal powder is used, heat treatment is performed at 800 ° C. for 2 hours in an inert atmosphere.

Subsequently, as shown in FIG. 6, the front and back surfaces of the insulating substrate 1 are planar-polished along the portion L of FIG. The electrode 3 is formed. Next, after forming the conductive film 5 which makes ohmic contact with the through electrode 3 on the surface of the insulating substrate 1, the magneto-sensitive film 4 is formed between the conductive films 5. Next, a protective film 6 made of an oxide film or the like is formed to protect the magnetic sensitive film 4 and the conductive film 5, and then a protective coating portion 9 made of an epoxy resin or the like is further formed.

On the other hand, after forming the electrode portion 7 which makes ohmic contact with the through electrode 3 on the back surface of the insulating substrate 1, the solder bump 8 is formed on the surface of the electrode portion 7 by solder reflow. The insulating substrate 1 of FIG. 1 is manufactured by the above steps.

According to the insulating substrate 1 of this embodiment, the through electrode 3 formed in the through hole 2 has a particle size of 10 to 90% of the diameter of the through hole 2, for example, one or more particles. The first metal powder 3A is formed by sintering a second metal powder 3B having a grain size smaller than that of the first metal powder 3A, for example, a plurality of grains of the second metal powder 3B, and a plurality of grains of the glass powder 3C. Since the conductive paste in which the fine powder metal of 1 μm or less is mixed is not used as described above, the shrinkage of the volume can be suppressed during the sintering process. Therefore, the through electrode 3 that completely closes the through hole 2 can be obtained.

Further, according to the method for manufacturing an insulating substrate of the present invention, the first metal powder 3A, the second metal powder 3B and the glass powder 3C are filled in the through hole 2 and then sintered and flattened. Since this is performed, the through electrode 3 that completely closes the through hole 2 can be formed without repeating the sintering process.
Therefore, the target through electrode 3 can be formed by one-time sintering treatment, so that an increase in cost can be prevented.

Furthermore, the first metal powder 3A having a large particle size
Is mixed and filled with the second metal powder 3B having a small particle diameter and the glass powder 3C having a small particle diameter, so that the volume shrinkage during the sintering process can be further suppressed. Further, when the atomized metal powder is used, the metal powder can be melted at a temperature lower than the melting point of the original metal, so that the metal powders can be completely melted and connected by low temperature sintering.

[0023]

As described above, according to the present invention, the first metal powder having a large particle diameter, the second metal powder having a small particle diameter, and the glass powder are filled in the through holes of the insulating substrate and baked. Since the through electrodes are connected to each other to form the through electrodes, it is possible to provide the insulating substrate having the through electrodes in which the through holes are completely closed and the manufacturing method thereof, without increasing the cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an insulating substrate of the present invention.

FIG. 2 is a perspective view showing an embodiment of an insulating substrate of the present invention.

FIG. 3 is a cross-sectional view showing a step in the method for producing an insulating substrate of the present invention.

FIG. 4 is a cross-sectional view showing another step of the method for manufacturing an insulating substrate of the present invention.

FIG. 5 is a cross-sectional view showing another step of the method for manufacturing an insulating substrate of the present invention.

FIG. 6 is a cross-sectional view showing another step of the method for manufacturing an insulating substrate of the present invention.

FIG. 7 is a cross-sectional view showing a conventional insulating substrate.

[Explanation of symbols]

 1 Insulating Substrate 2 Through Hole 3 Through Electrode 3A First Metal Powder 3B Second Metal Powder 3C Glass Powder 4 Magnetic Sensitive Film 5 Conductive Film 6 Protective Film 7 Electrode Part 8 Solder Bump 9 Protective Cover Part

Claims (3)

[Claims] 1. An insulating substrate having a conductive through electrode in a through hole penetrating in the front-back direction, the through electrode being formed of a metal powder sintered body, wherein the through electrode has a diameter of the through hole. A first metal powder having a particle size of 10 to 90% and this first
An insulating substrate formed from a second metal powder having a particle diameter smaller than that of the above metal powder and a glass powder. 2. The insulating substrate according to claim 1, wherein the insulating substrate is formed from at least one or more particles of the first metal powder, a plurality of particles of the second metal powder, and a glass powder. 3. (a) The diameter of the through hole of the insulating substrate is 10 to 9
At least one or more first metal powders having a particle size of 0% and a plurality of second powders having a particle size smaller than that of the first metal powders.
And (b) filling the through hole with the metal powder of No. 1 and a plurality of glass powders having a particle size smaller than that of the first metal powder,
The insulating substrate is heated to heat the first metal powder and the second metal powder.
A step of sintering the metal powder and the glass powder,
(C) A step of polishing the front and back surfaces of the insulating substrate by plane polishing, at least.