JPS61256601A - High molecular thin film thermosensitive element - 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 Industrial Application] The present invention relates to a polymer thin film temperature-sensitive element. More specifically, the present invention relates to a polymer thin film temperature-sensitive element that has excellent environmental resistance and is capable of accurately measuring temperatures in a medium temperature range.

[Prior Art] and [Problems to be Solved by the Invention] Typical elements that detect temperature based on resistance changes include metal resistors and thermistors. Platinum is used as a resistor metal when precision is required, but it is expensive.

Therefore, inexpensive nickel and copper are generally used,
These do not have sufficient accuracy, and the amount of resistance change is 1% or less per 1°C.

In addition, thermistors have better sensitivity than metal resistors, and the resistance change per 1 degree Celsius is usually as large as 3 to 5%, but in the fields of biomedicine and chemistry, they are used in the medium temperature range (0 to 100 degrees Celsius).
It is necessary to accurately measure the temperature of There is also a problem with reliability because it becomes noise due to the influence of electromagnetic waves and moisture.

The inventor of the present invention avoided these drawbacks found in conventional metal resistors and thermistors, and created a device with excellent environmental resistance.

Moreover, as a result of various studies in search of a temperature-sensitive element that can accurately measure temperatures in the medium temperature range, we have discovered that a polymer thin-film temperature-sensitive element with the following structure can effectively solve this problem. .

[Means for Solving the Problems] and [Operation] Accordingly, the present invention relates to a polymer thin film temperature sensing element, which comprises conductive comb-shaped electrodes formed on an insulating substrate. The surface of the device is sequentially covered with a thin polymer film (a) having excellent temperature-sensitive properties and a polymer film (b) having an insulating and moisture-absorbing property.

Formation of conductive comb-shaped electrodes on an insulating substrate is performed as follows. That is, glass, quartz, alumina, etc. are generally used as the insulating substrate, and a glass plate is generally used, and stainless steel, Hastelloy C, etc. are used on the surface of the insulating substrate.
Corrosion-resistant metals such as Inconel, Monel, and gold, as well as electrode forming material metals such as silver and aluminum, are prepared by sputtering, ion blasting, etc. to approximately 0.1 to 0.5 μm.
It is formed in the form of a thin film with a thickness of about m.

For example, in the case of aluminum, a photoresist pattern is formed on the metal thin film of the electrode forming material thus formed by applying a well-known photolithography process. That is, a photoresist coating is applied to a metal thin film, a glass dry plate on which a negative or positive image of a comb-shaped electrode pattern is printed is placed on top of the photoresist coating, and the photoresist is printed by light irradiation and developed. After this, wet chemical etching is performed, but the etching solution is
Phosphoric acid-sulfuric acid-phochromic acid-water (weight ratio 65:1
5:5:15) Mixed liquid, BHF (hydrofluoric acid)
, ferric chloride aqueous solution, nitric acid, phosphoric acid-nitric acid mixture, etc. are used.

The surface of the conductive comb-shaped electrode thus formed on the insulating substrate is covered with a polymer thin film (a) having excellent temperature-sensitive properties. The formation of this polymer thin film is generally performed by a plasma polymerization method, and examples of monomers to be plasma polymerized include nitrogen-containing organic silicones such as trimethylsilyldimethylamine, triethylsilazane, hexamethyldisilazane, and hexamethylcyclotrisilazane. elementary compounds are used.

By this plasma polymerization method, a thin polymer film with a thickness of about 0.3 to 0.6 μm is formed except for the extraction electrode part, but the plasma polymerized film that is formed has high electrical resistance and is usually insulating. However, its resistance value can be lowered by bringing its surface into contact with an alkyl halide gas such as methyl bromide, ethyl bromide, methyl iodide, or ethyl iodide.

This is thought to be because bromine and iodine are incorporated into the film through chemical reactions and diffusion phenomena, thereby improving conductivity.

The thin polymer film whose surface is preferably treated with an alkyl halide is an insulating and moisture-absorbing polymer film, such as an epoxy resin, a polyimide resin, a polyester resin, a polycarbonate resin, a polyethylene resin, a polystyrene resin,
At least the entire surface of the polymer thin film (a) is covered with a coating resin film (b) made of fluororesin, cellulose acetate, or the like.

FIG. 1 of the drawings is a plan view showing one embodiment of the polymer thin film thermosensitive element according to the present invention, in which conductive comb-shaped electrodes 12 and 12' are formed on an insulating substrate 11, and the surface thereof is are sequentially covered with a plasma polymerized film 13 and an epoxy resin film 14, and lead wires 17° and 17' are connected to the lead electrodes 15 and 15' not covered by these films by soldering or silver paste 16 and 16'. installed.

〔Effect of the invention〕

The polymer thin film temperature-sensitive element according to the present invention has higher sensitivity than conventional metal resistors and thermistors, and has good measurement accuracy in the medium humidity range. Eliminate the effects of humidity.

Good environmental resistance and increased reliability. Moreover, since the material is mainly a polymer material, it is inexpensive.

〔Example〕

Next, the present invention will be explained with reference to examples.

Example As shown in FIG. 1, aluminum-silicon (99:
By wet chemical etching the sputtered thin film of 1), a width of 50 μm, an interval of 100 μm layers, and a thickness of 0.2 μm was obtained.
A large number of m linear teeth with a length of 131 were formed.

A comb-shaped electrode is formed with opposing linear teeth meshing with each other in a portion corresponding to 11 m+ of the length, and then a plasma polymerized film of trimethylsilylmethylamine is applied to the comb-shaped electrode portion. The plasma polymerized film was formed so as to cover the film, and then methyl bromide gas was brought into contact with this plasma polymerized film to improve its conductivity. Finally, the entire plasma-polymerized film was covered with epoxy resin, which is an insulating and moisture-absorbing polymer. When the resistance value of this polymer thin film temperature-sensitive element was measured in the medium humidity region, the graph in Figure 2 shows the results. results were obtained, that is, approximately 1% per 1°C from 0 to 50°C.
Further, at 50 to 100°C, a resistance change of 6% or more per 1°C was observed, indicating high sensitivity.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of a polymer thin film temperature-sensitive element according to the present invention. FIG. 2 is a graph showing the measurement results using the polymer thin film thermosensitive element of the example. (Explanation of symbols) 11... Insulating substrate 12... Conductive comb-shaped electrode 13... Plasma polymerized film 14... Epoxy resin film

Claims (1)

[Claims] 1. The surface of a conductive comb-shaped electrode formed on an insulating substrate is covered with a thin polymer film (a) having excellent temperature-sensitive properties and a polymer film (b) having an insulating and moisture-absorbing property. A polymer thin film temperature-sensitive element that is successively covered with 2. Claim 1, wherein the polymer thin film (a) is formed of a plasma polymerized film of a nitrogen-containing organosilicon compound.
The polymer thin film temperature-sensitive element described in . 3. The polymer thin film temperature-sensitive element according to claim 2, wherein the plasma polymerized film is treated with an alkyl halide.