JPH03174701A - Manufacture of thermistor and system for manufacturing the same - Google Patents

Abstract

PURPOSE:To accurately control a resistance value of a thermistor element by irradiating part of an electrode with a laser beam to evaporate the part and controlling a reduction amount of the area of the electrode. CONSTITUTION:An oxide semiconductor 1 is formed in a desired shape, and electrodes 2a, 2b are formed to form a thermistor. A resistance value between the electrodes 2a and 2b is measured. If the resistance is smaller than a designed value, part of the electrode 2a is laser-trimmed, that is, evaporated by energy of a laser light to reduce the area of the electrode by a predetermined amount. Accordingly, the resistance of the electrode removing part can be enhanced, and the resistance value as a thermistor element can be raised to a design value by controlling the removing area of the electrode. Thus, an accurate resistance value can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method and system for manufacturing a thermistor, and particularly to adjusting the resistance value thereof.

(Prior Art) Oxide semiconductors such as Mn203 and CO203 can be freely adjusted in resistance by adding impurities and have a large negative temperature coefficient, so they are called NTC thermistors and are widely used.

On the other hand, add Y, Nd, etc. to BaTiO3 at 0.1 to 0°2at.
% doped oxide semiconductor has a large positive temperature coefficient and is therefore called a PTC thermistor.

Examples of such thermistors include Ba, Ti, Sr, Nd, Ca, AI, and F, as shown in FIG. 11(a).
The thermistor body 1 is formed by sintering oxides, carbonates, nitrates, chlorides, etc. of metals such as e, Ni, Mn, Mo, Cu, etc., and is formed into a thin r'l column shape, etc., and the upper and lower surfaces thereof are The electrodes 2a and 2b are formed by applying a silver (Ag) paste through a Ni plating layer.

Among such thermistors, an example of the relationship between the resistance value and temperature of a PTC thermistor is shown in Fig. 12, which shows that the temperature range having a large temperature coefficient of 1E can be adjusted by adding Sr, Pb, etc. Since then, it has become indispensable in a wide variety of fields, including circuit elements for temperature measurement and overcurrent prevention, motor starting, color TV demagnetization, and low-temperature heaters.

On the other hand, NTC thermistors are also indispensable as circuit elements used for temperature measurement and control, compensation, gain adjustment, power measurement, and the like.

Incidentally, the resistance value exhibited by a thermistor depends on the constituent materials of the thermistor body, the mixing ratio of the materials, manufacturing conditions such as sintering, the size, etc. For this reason, although the resistance value indicated by the thermistor is easy to adjust, there is a problem in that it is likely to vary.

However, as mentioned above, the use of thermistor is
Temperature measurement and control, compensation, gain adjustment, power measurement, overcurrent prevention, motor starting, color TV degaussing, etc., all require highly accurate resistance value control, and R±
It is necessary to use one within the range of α%.

For this reason, among those outside the range of R±α%, those with a resistance value lower than R are usually
] As shown in ), trim the thermistor body along with the electrodes by polishing or other methods to reduce the resistance value.
A measure is taken to keep the burnt temperature within the range of R±α%.

However, with this method, the thermistor body is scraped off together with the electrodes, which requires a great deal of effort, and there are problems in that it is extremely difficult to control the volume to be scraped off.

(Problems to be Solved by the Invention) As described above, in the conventional trimming method, since the thermistor body is scraped off together with the electrode, there is a problem in that it is extremely difficult to control the volume to be scraped off with high precision.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a thermistor that can easily control the resistance value with high precision.

[Structure of the invention]

(Means for Solving the Problems) Therefore, in the present invention, after forming a semiconductor into a desired shape and forming an electrode to form a thermistor, the resistance value is measured, and the resistance is lower than the predetermined value. In contrast, part of the electrode is removed by laser irradiation to increase the resistance value to the designed value.

Further, in the manufacturing system of the present invention, the thermistor producing means, the resistance value measuring means for measuring the resistance value of the thermistor produced by the thermistor producing means, and the thermistor measuring means for measuring the resistance value in the resistance value measuring means. The device is equipped with a constant temperature means for maintaining the thermistor at a constant temperature condition, and a laser trimming means for removing a part of the electrode of the thermistor by laser irradiation.

Furthermore, the manufacturing system of the present invention is provided with a sorting means for sorting according to what value is taken with respect to the design value R based on the measurement result of the resistance value measuring means, and according to the sorting result of the sorting means. , the laser trimming conditions are set in stages.

Furthermore, the manufacturing system of the present invention further includes a sorting means for sorting according to what value is taken with respect to the design value R based on the measurement result of the resistance value measuring means, and the sorting result of the sorting means is further provided. The apparatus is provided with a calculation means for calculating laser trimming conditions according to the calculation means, and the trimming conditions of the laser trimming means are sequentially controlled based on the calculation results of the calculation means.

(Function) According to the above method, by evaporating a part of the thermistor's electrode with the energy of laser light and reducing the electrode area, the resistance of the electrode extraction part can be increased, and the resistance value as a thermistor element can be increased. Since the resistance value can be increased, it becomes possible to control the resistance value with high accuracy by controlling the removed area of the electrode.

By the way, a laser trimming method in which a substance is evaporated by laser irradiation is a method that has been widely used for trimming the resistance value of a resistor. However, since the resistance value is measured at the same time as the laser irradiation, the resistance 1FrL of the thermistor is determined with Al1J in a state where the temperature has risen by 200 yen due to the energy received during the laser irradiation. Therefore, since the resistance value is determined due to temperature changes (resistance value -) while the resistance value remains unchanged, the actual value often deviates from the set value.

Therefore, in the manufacturing system of the present invention, since the resistance value measuring means is equipped with a constant temperature means for maintaining the thermistor at a constant temperature condition when measuring the resistance value, it is possible to always measure the temperature at a constant temperature. , it becomes possible to perform highly accurate resistance value adjustment.

Furthermore, the manufacturing system of the present invention is provided with a selection means for selecting in stages according to what value is taken with respect to the design value R, based on the measurement result of the resistance value 7IIlj determination means,
According to the sorting results of the sorting means, trimming is performed while controlling the racer rimming conditions sequentially for each item belonging to that stage, so it is possible to control the resistance value at a higher speed. becomes.

Furthermore, the manufacturing system of the present invention further includes a sorting means for sorting based on the measurement result of the resistance value measuring means, depending on what value is taken for proposition 1 value R,
The amount to be removed by racer rimming is calculated according to the sorting results of the sorting means, and the racer rimming conditions are determined sequentially, making it possible to obtain the desired resistance value at a higher speed. It becomes possible.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a flowchart 1 showing a process for manufacturing a thermistor according to an embodiment of the present invention.

First, form the thermistor using the usual method (step)
00).

That is, as shown in FIG. 2(a), Ni0Mn20
3, C0203 powder was mixed in a predetermined ratio and pressure-molded into 4 discs by the cooling press method, and then 12
After sintering at 00°C to form a disk-shaped thermistor body 1, electric conductors 2a and 2b were formed using Ag paste on the upper and lower surfaces of the thermistor body 1, and burned at 700°C to form a disc-shaped thermistor body 1 with a diameter of 4.47 mm. Form a thermistor.

Thereafter, the probe of the resistance measuring device is brought into contact with the electrodes 2a and 2b of the thermistor, and the resistance between the electrodes 2a and 2b is measured (step 1.01).

Then, this measured value or the set value R (here] OKΩ)
It is determined whether or not the error range is within a predetermined error range α% (step 102).

Then, those within the range of R±α% are considered complete and transferred to the conveyance line (step 103).

Further, it is determined whether the measured resistance value is R+α% or more (Step 104), and if it is R+α% or more, the product is disposed of and removed from the production line (Step 105).

On the other hand, for those below R-α%, -laser i-rimming is performed, and as shown in FIG. (step 106), and then returns to the resistance value measurement step [0] to repeat the process of measuring the resistance value.

In this way, a thermistor whose resistance value is controlled within the range of R±α% is completed.

The results of measuring the relationship between the electrode area removal rate and the resistance change rate of the thermistor are shown in FIG. 3(a).

This figure also shows that by reducing the electrode area,
It can be seen that highly accurate resistance value control is possible.

1 Furthermore, it can be seen that the resistance value distribution of the thermistor obtained in this manner has an extremely good distribution, as shown in FIG. 3 (1)).

In this example, the ends of the two-sided electrode 2a are removed, but the shape of this removed part can be changed as necessary. For example, as shown in FIG. As shown in FIG. 4(1), part of both the upper and lower electrodes 2a and 2b may be removed. As shown in FIG. 4(C), a straight line may be removed by a laser. It is also possible to remove a part of the upper electrode, divide the electrode 2a into a large electrode 2S and a small electrode 2p, and use one of them as an electrode.

Further, as shown in FIG. 5, a part of the thermistor body 1 may be removed along with the electrodes 2a and 2b to obtain a desired resistance value.

In addition, in the above examples, NTC thermister was explained, Nip, Mn203, CO
In place of 203, powders of TiO2, BaCO3, and Nd2O3 are mixed at a predetermined ratio, pressure-formed into a disc shape using a cooling press, and then sintered at 1300°C to form a disc-shaped thermistor body. If formed in the same manner, a PTC thermistor can be obtained.

Example 2 Next, a second embodiment of the present invention will be described.

FIG. 6 is an explanatory diagram showing a thermistor manufacturing system according to a second embodiment of the present invention.

This thermistor manufacturing system, as shown in Figure 6,
A thermistor manufacturing means for manufacturing a thermistor] 1, a thermostatic chamber 12 that is always controlled at 25°C, and this thermostatic chamber] 2
a resistance measuring device 13 for measuring the resistance value of the thermistor 10 made by the thermistor making means 11;
and this resistance measuring device] 3, a laser trimming device 14 removes a part of the thermistor electrode by irradiating the laser beam L with J=t, and a transport device 14 transports the thermistor whose resistance value control has been completed. It is equipped with a line 15 and a disposal device 16 for discarding a thermistor that cannot be trimmed.

The laser trimming device 14 includes a YA3G laser 14a and an output control device 14b that controls the output of the YAG laser 14a.
5W, switch pulse oscillation frequency 51 (Hz scanning speed 25 mm/sec).

Next, the process of manufacturing a thermistor using this thermistor manufacturing system will be explained.

The manufacturing process is carried out in the same manner as in Flowchart 1 (FIG. 1) shown in Example 1.

That is, first, using the thermistor making means 11, the thermistor 10 is formed in the same manner as shown in the first embodiment. This thermistor 10 is made of N i O, Mn203 as in the first embodiment.

Ag on the top and bottom surfaces of the Co2O3 mixed powder sintered body 1
It is assumed that the electrodes 2a and 2b are formed using paste.

After this, the thermistor is placed in a constant temperature room 12 set at 25°C, and the probe of the resistance measuring device 13 is brought into contact with the electrodes 2a and 2b of the thermistor to determine the resistance between the electrodes 2a and 2b. (Step] 01).

4 Then, it is determined whether or not this measured value is within the predetermined error range α% for the design value R (here: OKΩ) (step 102), within the range of R±α%. If the item is located in , it is considered as completed and transferred to the conveyance line] 5 (step 103).

Furthermore, it is determined whether the measured resistance value is less than or equal to R+α% (step 104), and if it is greater than or equal to R+α%, the product is disposed of, removed from the production line, and transferred to the disposal device 16 (step 105).

On the other hand, if it is less than R-α%, it is transferred to the laser trimming device 14 and irradiated with a laser beam L to perform laser trimming, and as shown in FIG. 2(b), a part of the electrode 2a is It is evaporated by irradiation to reduce the electrode area by a predetermined amount (step 106).

Then, the process of measuring the resistance value using the resistance measuring instrument 13 and returning to measurement step 10 is repeated.

In this way, the resistance value is R5 with respect to the target value R. A thermistor controlled within ±α% is completed.

In the above embodiment, the NTC thermistor was explained, and in this case also, Ni0Mn203. C
TiO2, Bacoa, Nd20 instead of 020□3
By using powder No. 3, a PTC thermistor can be obtained.

Example 3 Next, a third embodiment of the present invention will be described.

FIG. 7 is an explanatory diagram showing a thermistor manufacturing system according to a third embodiment of the present invention.

This thermistor manufacturing system is based on the thermistor manufacturing system according to the second embodiment shown in FIG. 6, and further includes a laser trimming device [4] and a support base that supports the thermistor [O] as an XY stage 17 movable in the X-Y direction. This X
-Y stage] 7 is controlled by the control device 18 (=
In addition, the laser beam irradiation area can be controlled with high precision, and the other parts are configured exactly the same as the manufacturing system of the second embodiment. Identical parts have been given the same symbols.

By using this system, trimming can be performed with higher precision, making it possible to obtain a thermistor with a resistance value closer to the standard value.

Example 4 Next, a fourth embodiment of the present invention will be described.

FIG. 8 is an explanatory diagram showing a thermistor manufacturing system according to a fourth embodiment of the present invention.

This thermistor manufacturing system includes the thermistor manufacturing system according to the second embodiment shown in FIG. 6, and further includes a laser control device 19 for controlling the laser beam irradiation conditions in order to control the trimming position in the laser trimming device. In addition, the amount of laser irradiation to the electrodes of the thermistor 10 can be controlled with high precision, and the other parts are configured exactly the same as the thermistor manufacturing system of the second embodiment. Identical parts are given the same reference numerals.

7 By using this system, it is possible to perform trimming with higher precision as in Example 3, and it is possible to obtain a thermistor having a resistance value closer to the target value.

Example 5 Next, a fifth embodiment of the present invention will be described.

FIG. 9 is an explanatory diagram showing a thermistor manufacturing system according to a fifth embodiment of the present invention.

This thermistor manufacturing system has a thermistor manufacturing system according to the second embodiment shown in FIG. In addition to adding 20 (=1), calculate in advance how much electrode removal area should be used for each group of thermistors, and determine trimming conditions such as laser irradiation amount according to that value. The trimming conditions in the laser trimming device 14 are reset depending on whether the device belongs to the group shown in FIG. Identical parts are given the same reference numerals.

By using this system, it is possible to remove a large amount of a thermistor with a large amount of deviation from the [1 standard] by trimming, and it is possible to bring the value closer to the target value more quickly.

In this embodiment, the sorter 2o is formed integrally with the resistance measuring device 13 inside the thermostatic chamber 12, but it goes without saying that it may be placed outside the thermostatic chamber as a separate body from the resistance measuring device 13. Nor.

Example 6 Next, a sixth embodiment of the present invention will be described.

FIG. 10 is an explanatory diagram showing a thermistor manufacturing system according to a sixth embodiment of the present invention.

This thermistor manufacturing system was created with the intention of further automating the apparatus of Example 5 and enabling higher-speed trimming.

9. In other words, in addition to the thermistor manufacturing system of the second embodiment shown in FIG. Based on the measurement results, [
A sorting device 20s that sorts the thermistors into a plurality of groups according to the deviation from the standard value and sends out a sorting signal indicating whether the thermistors belong to the group is added. The thermistor is equipped with a memory that calculates in advance how much the electrode removal area should be according to each shifting star, and determines and stores trimming conditions such as laser irradiation amount according to the calculated value.
The device is characterized by the addition of an arithmetic processing circuit 22 that sends out a control signal for instructing the driving of the laser trimming device 14 in accordance with the thermistor number input from the counter 2 and the sorting signal from the sorting device 20s. Then, depending on which group the thermistor that has reached the laser trimming device 14 belongs to, the laser trimming device 14
The trimming conditions are automatically reset to 0. Note that 23 is a control device that drives the laser trimming device based on a control signal from the arithmetic processing circuit 22. Example 2 for other parts
The structure is exactly the same as the thermistor manufacturing system. Identical parts are given the same initial number.

By using this system, it is possible to increase the amount removed by trimming for a thermistor that has a large amount of deviation from the target value, and the trimming conditions are dynamically controlled 1"1 according to the amount of deviation. In this way, it is possible to approach the target value more quickly, and in this way, it is possible to perform trimming with higher precision, and it is possible to obtain a resistor having a resistance value closer to the target value.

In this device, the trimming conditions were controlled by controlling the laser trimming device, but the electrode removed area was controlled by the scanning speed of the X-Y stage as used in Example 3. Also good.

〔Effect of the invention〕

2] As explained above, according to the present invention, after the thermistor is formed, a part of the electrode of the thermistor is evaporated by laser light energy to reduce the electrode area, thereby increasing the resistance value of the thermistor element with high accuracy. It becomes possible to control the

In addition, the device of the present invention is equipped with a ↑ target temperature lower stage that maintains the thermistor under a constant temperature condition when measuring the resistance value with the resistance value All + ll set, and the resistance value is measured at a constant temperature, and the measurement result is Laser trimming is repeated based on the constant temperature F > 1 degree (7) IK b'L
Iu'j 5yJ 蛤wo行') is possible.

[Brief explanation of drawings]

FIG. 1 is a flowchart 1 showing the thermistor manufacturing process of the first embodiment of the present invention, and FIGS. 2(a) and 2([)) are diagrams showing the thermistor manufacturing process E. FIG. 3(a) is a diagram showing the relationship between the rate of change in electrode area and the rate of change in resistance value, and FIG. 3(b) is a diagram showing the resistance of the thermistor formed in the thermistor manufacturing process of the first embodiment of the present invention. Figures 4 and 25 are diagrams showing the value distribution, Figures 4 and 25 are diagrams showing modified examples of laser trimming locations, Figure 6 is a diagram showing a thermistor manufacturing system according to the second embodiment of the present invention, and Figure 7 is a diagram showing the thermistor manufacturing system according to the second embodiment of the present invention. A diagram showing a thermistor manufacturing system according to a third embodiment of the invention, FIG. 8 a diagram showing a thermistor manufacturing system according to a fourth embodiment of the invention, and FIGS. FIG. 10 is a diagram showing a thermistor manufacturing system according to a sixth embodiment of the present invention, and FIGS. 11(a) to 11(b) are diagrams showing a conventional thermistor trimming method. , FIG. 12 is a diagram showing the relationship between the resistance value and temperature of a PTC thermistor when the amount of impurities is changed. ]... Thermistor body, 2a, 2b... Electrode, 2S
...Large electrode, 2p...Small electrode, 10...Thermistor,
1]...Thermistor creation means, 12... Constant temperature room, 1
3... Resistance measuring device, 14... Laser trimming device,
15...Transportation line, 16...Disposal device, 17...
・X-Y stage, 18...control device, 19...laser control device, 20...selector, 2]...counter,
22... Arithmetic control device, 23... Control device. 3 Fumisuk's funeral [direct, 171tj'u] □Do - One funeral map (b) (a) (b) Figure 5 (C)

Claims (4)

[Claims] (1) A thermistor creation step in which a semiconductor is molded into a desired shape and electrodes are formed thereon to create a thermistor; a resistance value measurement step in which the resistance value of the thermistor is measured; and a measurement result in the resistance value measurement step. 1. A method of manufacturing a thermistor, comprising: a laser trimming step of removing a part of an electrode based on the base. (2) a thermistor producing means for forming a semiconductor into a desired shape and forming electrodes thereon to produce a thermistor; a resistance value measuring means for measuring the resistance value of the thermistor produced by the thermistor producing means; and the resistance value. A thermistor manufacturing system comprising: a constant temperature means for maintaining the thermistor under a constant temperature condition when measuring a resistance value in the measuring means; and a laser trimming means for removing a part of the electrode of the thermistor by laser irradiation. (3) In the thermistor manufacturing system, there is a sorting means for sorting according to the value R taken with respect to the design value R based on the measurement result of the resistance value measuring means, and a laser 3. The thermistor manufacturing system according to claim 2, further comprising a control means for controlling trimming conditions stepwise. (4) In the thermistor manufacturing system, a sorting means for sorting according to what value is taken with respect to the design value R based on the measurement result of the resistance value measuring means; and according to the sorting result of the said sorting means , calculating means for calculating the trimming amount according to the amount of deviation from the design value, determining the laser trimming conditions, and sequentially controlling the trimming conditions of the laser trimming means. (2) The thermistor manufacturing system described.