JPS59175580A - Heat generating resistor - 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 [Field of Application of the Invention] The present invention relates to means for forming a heating resistor in a material having a three-dimensional shape.

[Prior art]

Conventional heating resistors involve winding wires such as Pt around a three-dimensional material, which has drawbacks such as a long time required and variable resistance values.

OBJECTS OF THE INVENTION An object of the present invention is to provide a means for quickly and easily forming a heating resistor on a material having a three-dimensional shape with high precision.

[Summary of the invention]

In the present invention, in order to achieve the above object, the heating resistor is three-dimensionally processed by a laser processing method or an etching method.

Embodiment FIG. 1 shows the material of a bobbin used in the sensor section of a hot wire air flow meter. A metallic lead wire 2 is inserted and glued inside a hollow ceramic cylinder 1. FIG. 2 is a schematic flowchart of the laser trimming method, which is the first method of forming a Pt resistor using the bobbin 3 as a material. A film of Pt or the like is formed on the bobbin 3, which is a material, by a vacuum thin film forming method (evaporation method, ion blating method, sputtering method). This film serves as a heating resistor. Next, a thin film of P, etc. is cut off into a predetermined shape by laser trimming, and finally, a coating treatment is performed with glass or the like. Figure 3 shows an outline of the equipment used in the sputtering method, which is superior to other vacuum thin film forming methods in terms of adhesion strength, film distribution, rounding, and film thickness control. . A target power source 4 applies power to the target 5 as a cathode and the holder 6 as an anode. The bobbin 3 is installed on the holder 6. The inside of the container 9 is evacuated by the vacuum pump 7. cylinder 8
A gas such as sialbone is put into the container 9. By applying a voltage, a plasma state 10 is formed in the container 9, and argon positive ions 11 are caused to collide with the target 5.

Then, cis locust atoms 12 are released from target 5. When the sputtered atoms 12 begin to be generated stably, the shutter 13 is opened and the sputtered atoms 12 are attached to the bobbin 3.

FIG. 4 is a cross-sectional view of the bobbin 3 after sputtering the Pt film. Reference numeral 21 denotes a contact metal 21 inserted between the base ceramic 1 and the Pt film 20 in order to increase the adhesion strength of the Pt film 20. Usually, one of the following materials is used. -〇r, TI.

Ta1M, etc. P on top of this contact metal 21
A film 2 (l sputtered) is used as a heating resistor such as .

FIG. 5 schematically shows the process for sputtering. Pre-treatment is the process of removing dust and oil from the surface of the material. Next, a contact metal is formed on the surface of the material to increase adhesion, and then a Pt film that will become a heating resistor is sputtered. FIG. 6 shows the pre-processing process shown in FIG. 5. This is the process of removing dirt and oil from the surface of the material.

FIG. 7 schematically shows the process of sputtering the heating resistor. Before sputtering, the material is heated so that the sputtered atoms settle and adhere to the material, and the shutter is opened after the sputtered atoms are stably generated.

FIG. 8 schematically shows a laser processing device for cutting the Pt film formed on the bobbin 3 of the material into a desired shape. A ruby laser is used as the laser source 30 with a wavelength of 0.7 μm.
Laser light 31 of approximately The laser beam 31 is split into multiple parts by a splinter 32, one of which is split by a lens 33.
The light is focused onto the grain bobbin 3 and used for processing. The other laser beam passes through lenses 34 and 35 and is used by camera 36 as observation light. Further, the laser beam 31 is cut off by a shutter 37. The bobbin 3 is placed on a processing table 37 and processed.

FIG. 9 shows the configuration and operation of the processing table 37. Laser light 31 is focused onto bobbin 3.1. Since the bobbin 3 has a Pt film formed on its surface, the entire bobbin 3 is a four-electric body. The lead wire 2 of the bobbin 3 is held down by a non-conductive chunk 41. A conductive electrode 42 is provided inside the shutter 41 to constantly measure the resistance of the Pt film on the bobbin 3 even during processing. Further, the bobbin 3 is rotated and moved to the right by the action of the holder 43 and the screw 440 on the chuck 41.
P on the bobbin 3 is designed to cut the membrane into two pieces. During this processing, the electrical resistance of the Pt film is kept constant at dj11, and when it reaches a constant value, the vJ cutting process is stopped. This method eliminates variations in the Pt film resistance and leads to improved accuracy during mass production of sensors.

FIG. 10 shows a cross-sectional view (a) and a cross-sectional view (b) of the sensor processed through the above steps. The contact metal 52 and the Pt film 51 are completely cut to the surface of the ceramic part 1 by laser. With this processing, the 10th
As shown in Figure (b), the Pt film is cut into spiral shapes. The Pt film is also connected to the lead wire 2.

Figure 11 shows that the P tM' film is recoated with glass or the like on the film (1 (, P) to protect the P tM'.
Figure 2 shows ceramic l without forming contact metal.
A Pi film 51 is directly sputtered on the surface of the substrate and processed using a laser. This is for the purpose of cost reduction.

The above has described the processing method of P and H using a laser. Next, the processing method using chemical milling will be described. Chemical milling is a chemical etching also called chemical cutting method. Here, the purpose is to etch a three-dimensional shape. FIG. 13 shows an outline of the process. A Pt film is formed on the bobbin 3 as a material, and the other Pt films are processed by chemical milling to form a heating resistor.

Furthermore, the surface of the film is coated with Fi P if necessary.

FIG. 14 shows the chemical milling process. The process is divided into four parts: pre-treatment, masking, etching, and post-treatment. Masking with chemical milling is performed by forming a chemical-resistant film on the surface of the material, and then scraping and peeling it off. This peeled part of Pt
The membrane is etched. FIG. 15 illustrates this chemical milling process. FIG. 15<a) shows the bobbin 3 used for material. In FIG. 15(b), a Pt film 60 is formed on the bobbin 3. II), (C
) is P.

A maskant 61, which is a film, is formed on the membrane 60, and this maskant 61 is scored and peeled off as shown in FIG. 15(d). Next, etching is performed as shown in FIG. 15(e), and the part where the maskant 61 has been removed is removed. At this time, the film thickness is controlled by etching so that the P film is completely removed up to the surface of the ceramic 1. Finally, as a post-treatment, the residual film is removed (FIG. 15(f)). If the knee peeling of the maskant 61 shown in FIG. 15(d) is controlled, a Pt film with an arbitrary shape can be formed. Figure 15 @ is the -
I'll give you an example. It is a wire-shaped heating resistor. By the above method, the processing accuracy of the film, which can be etched into a three-dimensional shape, is greatly improved, and an accuracy on the order of several microns is achieved.

FIG. 16 shows a method of forming a heating resistor using etching technology. It is believed that this method enables ultra-fine processing in which the interval between the Pt films in contact with each other is very narrow (on the order of several tens of microns). Furthermore, since the Pt film is not etched but another substance is etched, the etching itself is easy. FIGS. 16(b) to 16(e) are enlarged views of the portions enclosed by circles in FIG. 16(a). First, apply SIO! to the surface of ceramic 1. A film 70 of alumina and a film 71 of alumina are formed (FIG. 16 Φ)). Next, as shown in FIG. 16(C), the alumina film 71 is etched. Then the 16th
In Figure (d), the etching solution is selected using the etched alumina film 71 as a mask, and the 5102 film 70 is etched. Here, a phenomenon called undercut occurs in which the etched portion 8102 sinks under the upper alumina film 71, as shown in section A in FIG. 16(d). Finally, as shown in FIG. 16(e), when P is deposited or sputtered, a Pt film 72 (a) is deposited on the alumina film 71 and a Pt film 72 (b) is deposited on the 8102 film 70. is formed. At this time, Fig. 16 (d
), the Pt film in 72(b) penetrated to the bottom of the alumina film due to the undercut part shown in part A of 72(b). P[The distance between the membranes 72(a) and 72(b) is very narrow;
Ultra-fine processing is achieved. Furthermore, if the etching shown in FIG. 16(C) is carried out into an arbitrary shape, a desired P film can be obtained.

FIG. 17 shows a method of sputtering a Pt film directly onto the bobbin 3 in a spiral shape using a three-dimensional object sputtering method. Here, steps such as etching are not necessary. The bobbin 3 moves left and right while rotating multiple times due to the action of the chuck 80 and the holder 81.

From the target 82, the sputtered atoms 83 pass through the mask 84.
It passes through the hole 85 and is attached onto the bobbin 3. here,
When the bobbin 3 rotates once while moving in the horizontal direction, a spiral Pt film is formed on the bobbin 3. FIG. 17(b) shows the shape of the mask 84. Near the center, there is a
There are several walls.

This method requires only a sputtering process, resulting in a significant cost reduction.

FIG. 18 shows the shape of a Pt film formed by the apparatus shown in FIG. 17. By controlling the rotational movement and horizontal movement of the bobbin 3, a spiral heating resistor as shown in FIG. 18 is formed. Further, a Pt film having an arbitrary shape can be formed depending on the shape of the hole 85 of the mask 84.

FIG. 19 is an application of FIG. 17, in which the bobbin 3 only performs multiple rotations on the chuck 80, and the mask 84 moves in the horizontal direction.

FIG. 20 shows a photoetching method for three-dimensional shapes.

The operation of the chuck 80, holder 811, and mask 84 is as follows:
This is similar to Figure 7. A Pt film and a photoresist layer are formed on the surface of the bobbin 3. In this method, this photoresist is exposed in a spiral pattern using the light source 90 and the mask 84. The light emitted from the light source 90 is focused by a mirror 91, passes through a shutter 92, and then passes through a lens 9.
3, the light is converted into parallel light, reaches the hole 85 of the mask 84, and is selectively radiated onto the bobbin 3.

FIG. 21 illustrates the three-dimensional photoetching process. Fig. 21 (b) to (f) id, Fig. 21 (
It is a figure which expanded the circle mark part of a). In FIG. 21(b), a PLLi2O2 photoresist film 1 is formed on the surface of the ceramic 1.
01 is formed. Next, as shown in FIG. 21(C), a portion of the photoresist layer 101 corresponding to the hole 85 of the mask 84 is exposed using the mask 84 and the light source 90. Next, remove the portions of the photoresist layer that will not be exposed to light (see Figure 21).
d)), etching ((e)), and P
After etching the T film, the remaining photoresist layer 102 is removed. As described above, microfabrication of the heating resistor of P is possible.

FIGS. 22 to 25 show heat generating resistors 200 on the bobbin 3 produced by the various Pi pattern forming methods described above.

Fig. 22 shows a case in which the miso is extremely thin, Fig. 23 shows a case in which the bobbin 3 is uniformly covered with a Pt film 200, and Fig. 24 shows a case in which the bobbin 3 is uniformly covered with a Pt film 200.
The figure shows a case in which a heating resistor 200 and a temperature compensation resistor 201 are separated and formed into a film shape, and FIG. 25 shows a case in which a Pt film 200 is formed on a streamlined bobbin 3.

〔Effect of the invention〕

In the present invention, since the heating resistor is formed by a method such as a laser processing method or an etching method, the accuracy of film formation can be greatly improved.

[Brief explanation of the drawing]

The figures all show embodiments of the present invention. Figure 1 is a structural diagram of a bobbin material, Figure 2 is a structural diagram of a resistor, Figure 3 is a schematic diagram of a device using a sputtering method, and Figure 4 is a cross section of a bobbin. Figure, 5th
- Figure 7 is a sputtering process diagram, Figure 8 is a schematic diagram of the laser processing device, Figure 9 is a cross-sectional view of the processing table, and Figures 10 to 1.
Figure 2 is a cross-sectional view of the sensor, and Figure 13. Fig. 14 is an etching process diagram, Fig. 15 is an explanatory diagram of a chemical milling process,
Fig. 16 is an explanatory diagram of the method for forming a heating resistor, Fig. 17 is an explanatory diagram of the sputtering method, Fig. 18 is a diagram of the shape of the Pt film, Fig. 19 is an explanatory diagram of an application of Fig. 17, and Fig. 20 is a photo explanatory diagram. An explanatory diagram of the etching method, Figure 21 is a photoetching process diagram, Figure 2
2 to 25 are explanatory diagrams of the heating resistor on the bobbin. 1... Ceramic cylinder, 2... Lead wire, 3...
Bobbin, 4... Power source, 6-... Holder, 7... Vacuum pump, 9... Volume 3rd mouth 4th country 5th day 6th day 9th day Eye drops 10 Mouth serving 71 mouth 5th 72nd b Ho 13 Prisoner 11 Shi 1 Wang H [j= 75th Vision 15th 76th Ho 77 Country 5 18th 18th / 9 Kuchi 4 20th (0-) (shi) Dormitory 21 Ageo 22nd 23rd Meji 24 prisoners

Claims (1)

[Claims] 1. A heating resistor that is a method of forming a heating resistor on a material having a three-dimensional shape, and is characterized in that it uses a method of forming a heating resistor such as a laser processing method or an etching method. .