JPS60120593A - Terminal structure of ceramic substrate - 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 [Industrial Field of Application] The present invention relates to a terminal structure of a ceramic substrate.

[Prior art] Traditionally, electronic circuits have been miniaturized and weighed by forming a pattern on a substrate made of ceramic material using a noble metal paste mainly made of white metal (gold) and sintering it. Things like this are being done.

Here, as shown in FIG. 1, for example, as shown in FIG. 1, electrodes 1as'ib are formed on the end surface of the substrate 1 using the noble metal paste. However, a normal lead wire 2 made of copper or the like is soldered A'', or as shown in FIG. There is a device in which a lead wire, for example, a platinum lead wire 5 is provided, a ceramic plate 6 is tightly attached thereon, and the platinum lead wire 5 is used as a terminal by integrally sintering it.

By the way, when such a ceramic substrate is used as a substrate for various detectors, for example, when used for a gas sensor that is attached to various combustion equipment and detects gas components such as oxygen concentration in exhaust gas, the former solder is used. The latter terminal structure using platinum lead wires cannot be used because it lacks heat resistance, and the latter terminal structure using platinum lead wires has good heat resistance, but the strength of the platinum itself is low, so reinforcing lead wires must be welded. Moreover, since platinum itself is expensive, there is a problem in that the manufacturing cost is high.

[Objective of the Invention J] Therefore, the present invention provides a terminal structure for a ceramic substrate that has heat resistance and can be produced at a relatively low cost, and also provides a highly reliable terminal of up to 4vJ. The purpose is to make it sufficiently durable even when used in detectors installed in places with high humidity and high vibration, such as in engines.

[Configuration J of the Invention The configuration of the present invention to achieve the above object is as shown in FIG. The gist is a terminal structure for a ceramic substrate characterized by having a noble metal plated lead wire (1) thermocompression bonded to the layer.

Here, the ceramic substrate (1) may be a commonly used ceramic substrate, such as a fired ceramic substrate containing alumina, herria, mullite, sudeatite, etc. as a main component.

Next, the lead wire to be used as the precious metal plated lead wire (■) may be, for example, a lead wire whose main component is copper, silver, iron, etc., or one plated with nickel, chromium, etc.
Although any commonly used lead wire may be used, it is particularly desirable to use a lead wire made of copper or an alloy thereof from the viewpoint of processing, cost, etc. Further, as the platinum plating in the noble metal plated lead wire (1), plating using a platinum metal such as platinum, palladium, or indium or gold may be used, and gold plating is particularly desirable from the viewpoint of bonding strength by thermocompression bonding.

The electrode layer (■) includes an electrode layer mainly composed of gold or platinum, similar to the above-mentioned noble metal plating. Among them, platinum has a moderate electrical resistance, so it is often used as a resistor in electric circuits and as a heater. There is. Therefore, it is desirable to use platinum because the electric circuit can be used as an electrode as it is.

Furthermore, in order to provide a durable electrode layer on the ceramic substrate, it is desirable to add an appropriate amount of ceramic powder.In this case, in order to further increase the bonding strength with the ceramic substrate, 4 to 20% of the ceramic powder is It is desirable to add it in proportion.

On the other hand, in order to increase the bonding strength with the noble metal lead wire, it is desirable to use the ceramic powder in a proportion of 4% or less. Therefore, by making the electrode layer into two layers, adding 4 to 20% of ceramic powder to the electrode layer on the substrate side, and 4% or less of ceramic powder to the electrode layer on the real metal lead wire side, the electrode layer, the ffl electrode layer and the lead wire can be stacked together. can further improve bonding. Furthermore, when the electrode layer is made of two layers as mentioned above, it is better to use platinum for the electrode layer on the substrate side for the reasons mentioned above, and platinum is used for the electrode layer on the noble metal lead wire side as described in the noble metal plating of the lead wire. It is more effective to use gold for

Next, thermocompression bonding involves heating and crimping the noble metal lead wire (■) and the electrode layer (■), melting the bonded portion, and adhering it. This can be done by pressing from above the wire in the direction of the electrode layer.

Hereinafter, μ2 will be explained with examples.

[Example] First, as the above ceramic substrate processing, the average particle size was 1°5 μm.
Nohetachi 201192% by weight, 5iOz4% by weight, CaO
Mixed powder 100 consisting of 2m% and M (102% by weight)
12 parts by weight of butyral resin and 6 parts by weight of dibdelphthalate were added to each part by weight, mixed in an organic solvent to make a chiller, and a green sheet with a thickness of 1 mm was made using a doctor blade. Next, as an electrode layer, a paste in which alumina (or glass) was added to platinum (or gold) in the proportions shown in the table below was thick-film printed on the green sheet. Thereafter, the thick film-printed green sheet was fired in the atmosphere at a temperature of 1500° C. for a holding time of 2 hours, thereby obtaining a ceramic substrate having an electrode layer (1).

Next, a copper lead wire with a diameter of 0.3 mm and a gold plating of 2.5 .mu.m was used as the noble metal plated lead wire (2), and a wire heated to 500.degree. C. was pressed with a force of 10 kg to perform thermocompression bonding.

The bonding strength of the terminal thus formed was determined by pulling the precious metal plated lead wire (■) in the vertical direction of the ceramic substrate (■) as shown by the broken line B in Figure 3, and measuring the strength of 918 between the nest plate and the electrode surface or between the electrode and the lead. It was measured as The measurement results are shown in the table below.

Here, NOl to NO5 in the table refer to the electrode layer
is one layer, with platinum as the main component and the proportion of alumina varied as shown in the table. NO6 and NO7 are electrode layers.
For NO6, the first layer, that is, the ceramic substrate side, is made of 80% platinum and 20% alumina, and the second layer,
In other words, the noble metal lead wire side was fired with 98% platinum and 2% alumina, and in NO7, the first layer was fired with 80% platinum and 20% alumina, and the second layer was fired with 95% gold and 5% glass. It is b. Further, the mark * in the NOI indicates that there was peeling between the ceramic substrate and the electrode layer, and in the other cases, there was peeling between the electrode layer and the lead wire.

As is clear from the table, when the electrode layer (■) is one layer, 10
It was found that electrode layer (2) containing % of alumina had the highest bonding strength. Moreover, when the electrode layer 1■ is made into two layers,
It was found that the strength was considerably increased compared to the case of one layer, and that if the second layer was made of an electrode layer mainly composed of gold, it was possible to obtain a bond strength of 6 times higher than that of the case where the second layer was made of platinum. Ta.

[Application Example] Next, a case will be described in which the terminal 1F4 structure of the present invention is applied to an oxygen sensor that detects the oxygen concentration in the exhaust gas of an internal combustion engine.

FIG. 4 is a partially sectional side view of the oxygen sensor.

In the figure, J5 has a detection element 11 on a ceramic substrate, and 10 is a detection part for detecting oxygen concentration, and 12 is a cylindrical shape for holding the detection part 10 and attaching this sensor to an internal combustion engine. The main metal fitting, 13 is the main metal fitting 12
is attached to the internal combustion engine side tip 12a of the detector 10.
A protector 14 is a first inner cylinder that holds the detection part 10 together with the metal shell 10, and
0 is a spacer 15, a filling powder 16 and a glass seal 17
It is held by the metal shell 10 and the inner cylinder 14 via. Here, the filling powder 16 is a 1:1 mixed powder of talc and glass, and the glass seal 17 is made of low melting point glass.
It is sealed at ℃ to prevent leakage of the detection gas. Further, a threaded portion 12b for attaching an internal combustion engine is carved on the outer periphery of the metal shell 12, and a gasket 1-18 is provided to prevent leakage at the portion where the internal combustion engine comes into contact with the wall. Te('Xru.

19 is attached to the metal shell 12 so as to cover the inner cylinder 14 (
20 is a sealing material made of silicone rubber, and has lead wires 21 to 23 and terminals 31 to 33 from the detection part 10 that protrude from the glass seal 17 (not shown in FIG. 5). This is to insulate and protect the connection parts of the

These lead wires 21 to 23 and the terminal 31 or tIX wire 33
For connection, as shown in FIG. 6, the seal 020 and the lead wires 21 to 23 are placed in the outer cylinder 19 in advance, and a crimping fitting 24 to 2 is attached to the tip of each lead wire 21 to 23.
6, and then fasten the crimping fittings 24 to 26 to the terminal 31.
This is done by caulking and connecting with 33 to 33.

Next, the detection unit 10 is shown in FIG.
Created according to the procedure.

In the figure, 40 and 41 are 20a, 92% by weight, 5iOz, with an average particle size of 1.5μm, as in the previous example.
12 parts by weight of butyral resin and 6 parts by weight of dibutyl phthalate (DBP) are added to 1.00 parts by weight of a mixed powder consisting of 4% by weight, 2% by weight of CaO, and 2% by weight of MgO, and mixed in an organic solvent to form a slurry. The green sheets are formed using a doctor blade, and the green sheets 40 are formed to have a thickness of In1 m, and the green sheets 1 to 41 are formed to have a thickness of 0°2111111. 42 to 47 are patterns printed with 19 layers of platinum paste added with 7% A-ZOa to PT, 42 and 43 are electrode patterns that become electrodes of the detection element 11, and 14 is a pattern that heats the detection probe 11. The heating resistor patterns 45 to 47 are electrodes for applying power to the heating resistor pattern 44 and the detection element 11 or for extracting detection signals, and are connected to the terminals 31 to 33, respectively. It is.

As shown in (a), the manufacturing of the present detection unit 10 is started by thick-film printing the patterns 42 to 47 on the green sheet 40 using platinum paste. As is clear from (b), rivers 1049 are formed by punching on the green sheet 1-41 so that the tips of the electrode patterns 42 and 43 are exposed, and the electric 4V patterns 42, 43 and 43 are formed on the green sheet 40. Electrode 45&)
Green sheets 41 are laminated and hot-pressed on green sheets 1 to 40 to cover all patterns except L 47. Thereafter, the laminated thermocompression-bonded green sheets 40 and 41 are left in the atmosphere at 1500° C. for 2 hours to sinter the ceramic substrate. Next (,:()\), the detection element 11 will be installed in the frontage 49.
μm Ti 02 powder 100 mol 81I1. :3 shishi 1
A molar amount of platinum black was added, and 3 mm% of ethyl cellulose was added to the powder, mixed in butyl calpitol, and the mixture was adjusted to a viscosity level in a 300 molar chair.
After printing a thick film of io2 paste so that it fills the opening 1] 49 and adheres to the tips of the electrode patterns 42 and 43, it is baked in the atmosphere at 1200°C. formed by

Next, the connection with the detection unit 10, Fil&+ 45 to 47, and pFJ' 31 to 33 is as shown in FIG.
fr is called. In addition, the terminals 31 to 33 are 0.3 m long.
It is integrally formed from a copper plate with a thickness of 2.5 μm and is plated with gold to a thickness of 2.5 μl.

First, as shown in FIG. 8(a), the terminals 31 to 33 are placed on the electrodes 45 to 47, respectively. and(
Heat the model 50 to 500°C as shown in b), and set each terminal 31 to 33 to 10! By pressing with + force, it is thermocompressed, making it possible to connect terminals that are resistant to heat and vibration.

The detection unit 10 created in this way is as described above (
It is held by the housing 12 and the inner cylinder 14 and is used to detect the degree of oxygen in the exhaust gas of the internal combustion engine. By heating the detection element 11 and detecting a change in the resistance value between the terminals 32 and 33, the amount of oxygen in the exhaust gas can be obtained.

As explained above, when the terminal structure of the present invention is applied to an oxygen sensor, the connection between the terminal and the mold bar of the ceramic substrate on which the detection element for detecting oxygen m-eating is formed is heated by a heated wedge. Terminal 4F4 is resistant to heat because it is crimped, and resistant to vibration because the terminal is made of copper plate.
M-sensor 4 has a durable structure and is an oxygen sensor.
) - becomes (qru).

In addition, in this oxygen sensor, since the connection part between the N pole and the terminal is fixed with low melting point glass, the terminal 41 is even more solid.
1 can be made into a structure.

[Effects of the Invention] As detailed above, the terminal structure of the ceramic substrate of the present invention connects the electrode layer mainly composed of noble metal formed on the ceramic substrate and the noble metal plated lead wire by thermocompression bonding. It is possible to create a durable terminal structure that is resistant to heat and vibration. In addition, after sintering the ceramic substrate, the negative metal plated lead wires are thermocompressed, making it easy to connect the terminals.Furthermore, there is no need to use precious metals themselves, just by plating the terminals with precious metals or metals. Since there is no such thing, it can be installed relatively cheaply.

[Brief explanation of the drawing]

1 and 2 are perspective views showing the terminal structure of a conventional ceramic substrate, FIG. 3 is a side view showing the terminal structure of the ceramic substrate of the present invention, and FIGS. 4 to 8 are perspective views showing the terminal structure of the ceramic substrate of the present invention. An application example in which the terminal structure is applied to an oxygen sensor is shown, and FIGS. 4 to 6 are partial sectional views showing the structure of the sensor, and FIG. 7 is a front view and A- A cross-sectional view taken along the line A, and FIG. 8 are a front view and a cross-sectional view taken along the line B-B showing the structure of the terminal 418 of the detection unit 10. ■... Ceramic substrate ■... Electrode layer ■... True metal plating lead wire Agent Patent attorney Tsutomu Adachi and one other person Figure 1 Figure 2 Figure 3 Figure 4 Figure 2 Figure 6 Figure 6 Figure 7 (A) (B) 40 4U (C)

Claims (1)

[Scope of Claims] 1. A device comprising a ceramic substrate, an electrode layer formed on the substrate and having a noble metal as a main component, and a noble metal plated lead wire thermocompressed to the electrode layer. Ceramic board terminal structure. 2 Soles whose precious metal plated lead wires are mainly made of copper:
The terminal structure of the ceramic board according to claim 1, which is a wire. 3. The terminal structure of a ceramic substrate according to claim 1 or 2, wherein the noble metal plated lead wire is a gold plated lead wire. 4 Special if the noble metal that is the main component of the electrode layer is platinum
1. A terminal structure for a ceramic substrate according to any one of claims 1 to 3. 5 The electrode layer is a laminate of two different compositions, of which the electrode layer on the ceramic substrate side is a noble metal layer containing 4 to 20% ceramic powder, and the electrode layer on the noble metal plated lead wire side is a ceramic powder layer containing 4% or less A terminal structure of a ceramic substrate according to any one of claims 1 to 4, which is a noble metal layer containing. 6 The electrode layer is a laminate with two different compositions, of which the electrode layer on the ceramic substrate side is a noble metal layer mainly composed of platinum, and the electrode layer on the noble metal plated lead wire side is a noble metal layer mainly composed of gold. A terminal structure for a ceramic substrate according to any one of claims 1 to 3. 7. The ceramic substrate terminal m structure according to any one of claims 1 to 6, wherein the thermocompression bonded portion of the noble metal plated lead wire is covered with a protective layer containing glass as a main component.