JP2889422B2 - Chip type thermistor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type thermistor and a method for manufacturing the same.

[0002]

2. Description of the Related Art In response to recent demands for miniaturization and weight reduction, electric components used have been miniaturized. This type of conventional thermistor is of a thick-film glaze chip type, and has a large variation in resistance value, so that a resistance value adjustment step is inevitable. In the conventional resistance value adjustment process, the specific resistance of the thermistor body is adjusted by calculating the electrode formation area calculated from the expected completed resistance value when forming the electrode, and printing the electrode on an insulating substrate by printing or the like. This is done by increasing or decreasing the area of the printed pattern when forming the pattern.

[0003]

However, in the conventional resistance value adjustment process alone, the resistance value is affected by the shift of the printing position when printing the electrode pattern, bleeding, blurring, variation in the film thickness, and the sintering temperature. And the printing accuracy was limited. For example, a variation of about ± 20% cannot be avoided.

[0004]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and has the following structure as one means for solving the above-mentioned problems. That is, given the size of the insulating substrate, a lower electrode formed on the first layer on the insulating substrate, and a thermistor body formed in said second layer on the insulating substrate, a third layer on said insulating substrate and an upper electrode black insulating layer is formed slightly larger upper formed, the thermistor resistance value adjustment, black insulation to the upper
Rezato at least a portion of the upper electrode edge layer is formed
That is lines of our by cutting the trimming
It is characterized by .

[0005] For example, the insulating substrate is an alumina substrate, the electrode is a silver-palladium thick film glaze, and the thermistor body is a glaze mainly composed of a Mn, Co, Fe, Cu complex oxide.

[0006]

In the above configuration, since the resistance value can be adjusted to a desired resistance value with high accuracy without substantially affecting the thermistor body sandwiched between the electrodes, the change with time is small, and the thermistor with high reliability is obtained. Can be provided. Furthermore, in this case, a black insulating layer should be formed at the resistance value adjustment point.
Improves the absorption of laser light (increases greatly)
Can be cut or cut instantly without the influence of heat,
While eliminating the need for special cooling mechanisms such as air blowing,
The effect of heat can be prevented and the effect of mass production can be improved.
Wear. In addition, it is possible to perform insulation coating at the same time.
Excellent effects can be achieved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to the drawings. 1 to 5 are views for explaining an embodiment according to the present invention, FIG. 1 is a cross-sectional view showing a configuration of an embodiment according to the present invention, FIG. FIG. 3 is a cross-sectional view showing a state in which a lower electrode is formed in the present embodiment.
FIG. 4 is a cross-sectional view illustrating a state where the thermistor body of the present embodiment is formed, and FIG. 5 is a view illustrating a completed state of the present embodiment.
(A) is a sectional view, and (B) is a plan view.

In FIG. 1, reference numeral 10 denotes an alumina substrate which is an insulating substrate. In this embodiment, a sintered body of 96% alumina is used. Reference numerals 11 and 21 denote lower electrode patterns provided on the alumina substrate 10, and 11 denotes an alumina substrate 10 extending from one end of the alumina substrate 10 to the other end.
A lower electrode 21 is disposed over the entire width of the alumina substrate 10 up to the position shown in the cross-sectional view. An upper electrode 21 connects an upper electrode 22 disposed at a predetermined width over the entire width of the alumina substrate 10 from the other end of the alumina substrate 10. This is the lead section.

Reference numeral 22 denotes an upper electrode which is electrically connected to the upper electrode lead portion 21 and is provided with a predetermined width and a predetermined length so as to maintain an electrical connection state on the upper surface of the thermistor body 23; It is. In the present embodiment, as will be described later, the end of the upper surface of the thermistor body 23 of the upper electrode 22 is cut (trimmed) as necessary to adjust the thermistor resistance to a desired value.

In this embodiment, a silver-palladium thick film glaze is used as the electrode, and a thermistor body is a thick film glaze mainly composed of a Mn, Co, Fe, Cu complex oxide. I have. The glaze is heated and fired. Hereinafter, a method of manufacturing the chip-type thermistor of the present embodiment having the above-described configuration will be described with reference to the process chart of FIG. 2 and FIGS.

The following description is not limited to the case where only one thermistor is manufactured, and it goes without saying that a large number of thermistors can be manufactured at the same time. And
In the final step, the thermistor may be separated into one thermistor. First, in step 1 shown in FIG. 2, an alumina substrate manufacturing step of forming the alumina substrate 10 to a predetermined size is executed, and an alumina substrate having a size of a predetermined manufacturing unit is manufactured. This unit is an arbitrary size. Even if it is created for each thermistor,
For example, dozens of them may be produced at the same time, and production may be made according to each case.

Subsequently, in step 2, an electrode pattern of a lower electrode is formed on the upper surface of the alumina substrate 10 as shown in FIG. In this embodiment, as described above, the alumina substrate 10
The lower electrode 1 is arranged from the one end toward the other end to the position shown in the cross-sectional view over the entire width of the alumina substrate 10.
1. Alumina substrate 10 from the other end of alumina substrate 10
Upper electrode lead portion 21 provided with a predetermined width over the entire width of
Alumina substrate 1 by printing / etching etc.
0. Then, for example, a lower electrode forming step of forming an electrode by heating and baking at 850 ° C. for about ten minutes is performed. FIG. 3 shows a state after the execution of the lower electrode forming step.
Although the following state diagrams for each step only show one single chip, the same applies to the case where a plurality of chips are simultaneously formed.

Then, a thermistor body 23 is formed on the lower electrode patterns 11 and 21 thus formed in step 3 by printing or the like, and is baked at 850 ° C. for about 10 minutes. Execute. FIG. 4 shows a state where the thermistor body is formed. In the figure, 23
Is a thermistor body. In this embodiment, the thermistor body 23 is formed over the entire width of the alumina substrate 10 except for a certain width from both ends of the lower electrode patterns 11 and 21. However, the formation area may be an area corresponding to the resistance value of the thermistor, and may be near the center.

Subsequently, in step 4, the upper electrode lead portion 21 is formed.
In order to cover the surface of the thermistor body 23 from the surface where the thermistor body 23 is not formed, the alumina substrate 10 is formed by a method such as printing / etching so as to extend a predetermined length and a predetermined length in one end direction. Then, an upper electrode forming step of forming the upper electrode 22 by heating and baking at 850 ° C. for about ten minutes is executed. As a result, a resistance value appears between the lower electrode 11 and the upper electrode 22. In the present embodiment, the formation electrode area of the upper electrode 22 is previously reduced so that the resistance value that appears at this time becomes lower than the target resistance value. Form larger.

In the above example, the electrodes 11, 21 and 21 are used.
The firing of 23 and the firing of the thermistor body 23 are performed for each step,
Although an example in which each is performed separately has been described, the present embodiment is not limited to this example, and firing is not performed in each forming process, and firing is performed collectively after forming the upper electrode pattern by printing or the like.
Any two may be fired together. Then, an upper electrode cutting step of cutting a required amount of the end of the upper electrode 22 is performed so that the resistance value of the thermistor formed as described above in step 5 becomes a predetermined resistance value. The resistance value of the thermistor chip is determined by the size of the thermistor body 23 sandwiched between the lower electrode 11 and the upper electrode 22, and the area of the overlapping portion of the two electrodes 11, 22 is (S), and the thermistor body 23 of this part Is the thickness of the thermistor body (t) and the specific resistance of the thermistor body is (ρ), the obtained resistance value R is R = ρ
(T / S). Therefore, first, the initial resistance value is measured, the area to be cut is calculated, the actual cutting size is obtained, and the end of the upper electrode 22 is cut by the obtained amount, thereby obtaining the above ( S) can be reduced, and a desired resistance value can be obtained.

FIG. 5 shows a state after execution of the upper electrode cutting step.
Shown in In FIG. 5, reference numeral 12 denotes a lower electrode disposed below the thermistor body 23, and reference numeral 30 denotes a cut portion of the upper electrode. When the cutting step 5 is performed by laser trimming, it is desirable to take measures against heat generation during cutting. For example, by blowing low-temperature air, the whole may be cooled to prevent the influence of heat.

Then, in step 6, a thermistor is separated and formed for each chip as needed. For example, if a large number of thermistors are manufactured simultaneously,
If each chip is separated and molded and one chip is manufactured, the peripheral portion is shaped. The chip thermistor of the present embodiment manufactured in this way has, for example, a width of approximately 1.2.
3 mm ± 0.1 mm, approximately 2.0 mm ± 0.1 mm in length, approximately 0.5 mm ± 0.1 mm in thickness of the alumina substrate 10, approximately 10 μm ± 2 μm in thickness of the electrode portion, and the thickness of the thermistor body 23 It is formed to a thickness of approximately 40 μm plus or minus 5 μm. Alternatively, as another example, for example, approximately 1.6 mm plus or minus 0.1 mm and approximately 3.2 mm plus or minus 0.3 mm.
1 mm, the thickness of the alumina substrate 10 is approximately 0.6 mm ± 0.1 mm, the thickness of the electrode portion is approximately 10 μm ± 2 μm, and the thickness of the thermistor body 23 is approximately 40 μm ± 5 μm.

In this embodiment, since the resistance value is adjusted by performing the trimming process, the variation in the resistance value can be suppressed to approximately ± 5% or less. In addition, since the resistance value can be adjusted without substantially affecting the thermistor body 23 sandwiched between the electrodes, a highly reliable thermistor with little change over time can be provided. Furthermore, in this case,
Since the resistance value can be adjusted later, there is no need to print the electrodes and the thermistor body with high accuracy, and the effect of mass production is enhanced.

[Other Embodiments] In the above description, when cutting is performed by laser trimming, air having a low temperature is blown to prevent the influence of heat generated during trimming. The present invention is not limited to the above example, and it is needless to say that any method can be applied as long as the temperature can be lowered by some method or the influence of the temperature can be reduced.

For example, after forming the upper electrode 22 in step 4, a step of forming a black insulating layer on the upper electrode 23, for example, with lead glass glaze used as a protective coat, is added. A method of cutting the upper electrode later from the cut portion by laser trimming can efficiently obtain a desired resistance value. That is, by forming the black insulating layer, the absorbency of laser light can be improved (increased greatly), and cutting or cutting can be performed instantaneously without the influence of heat. In this case, the influence of heat can be prevented while eliminating the need for a special cooling mechanism such as air blowing.
Further, the effect of mass production can be improved. In this case, the excellent effect that the insulating coating can be performed at the same time can be achieved at the same time.

[0021]

As described above, according to the present invention, the resistance value can be adjusted to a desired resistance value with high precision without substantially affecting the thermistor body sandwiched between the electrodes. And a highly reliable thermistor can be provided. Furthermore, in this case as well, the black
By forming an edge layer, laser light absorption is improved.
(Significantly increase), instantaneously without heat
Special cooling mechanism such as cutting or cutting and blowing air
Prevents the effects of heat while eliminating the need for mass production
Fruit can be raised. At the same time, perform insulation coating
The excellent effect that can be achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of an embodiment according to the present invention.

FIG. 2 is a manufacturing process diagram of the present embodiment.

FIG. 3 is a cross-sectional view illustrating a state in which a lower electrode is formed in the present example.

FIG. 4 is a cross-sectional view showing a state where a thermistor body of the present embodiment is formed.

FIG. 5 is a diagram showing an example of a completed state of the embodiment;
(A) is a sectional view, and (B) is a plan view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Alumina substrate 11, 12 Lower electrode 21 Lead for upper electrode 22 Upper electrode 23 Thermistor body 30 Trimming part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01C 7/02-7/22

Claims (3)

(57) [Claims] [1 claim: a dielectric substrate having a predetermined size, the lower electrode formed on the first layer on the insulating substrate, and a thermistor body formed in a second layer on the insulating substrate, on said insulating substrate Slightly larger upper part formed in the third layer
And an upper electrode on which a black insulating layer is formed . The thermistor resistance adjustment is performed by forming the black insulating layer on the upper part.
Laser trimming at least part of the upper electrode
A chip type thermistor characterized by being cut more . 2. An insulating substrate is an alumina substrate, electrodes are silver-palladium thick film glaze, and the thermistor body is Mn, C
Glaze , black mainly composed of o, Fe, Cu based composite oxide
The chip type thermistor according to claim 1, wherein the color insulating layer is a lead glass glaze used as a protective coat . 3. A method for manufacturing a chip-type thermistor, comprising forming a thermistor body on an insulating substrate having a predetermined size, wherein a lower electrode is formed on a first layer on the insulating substrate having a predetermined size. A step of forming a thermistor body on a second layer on the insulating substrate including at least a part of the lower electrode; and at least a part of the thermistor body formed on the lower electrode. An upper electrode forming step of forming a slightly larger upper electrode on the third layer on the insulating substrate, and an insulating layer forming a black insulating layer on the formed upper electrode
A step, a portion of the black insulating layer is formed the upper electrode on the thermistor body so that the thermistor body becomes the predetermined resistance value Leh
And a trimming step of cutting by trimming.