JPS6140526A - Temperature sensor - Google Patents

Abstract

PURPOSE:To improve sensitivity and response by reducing heat capacity, by providing a membrane like bridge part to a temp. sensitive part. CONSTITUTION:A thermistor material layer 5 is provided to the membrane like bridge part of a bridge structure and superposed to two conductor layers 4a, 4b so as to be held between the conductor layers 4a, 4b in the vicinity of the center of the bridge structure to detect electric resistance only in the thickness direction of the thermistor material layer 5 in the superposed region. By this constitution, the heat capacity of the bridge part can be reduced and, because the bridge part is a membrane like one, the contact area with gas in vacuum is largely taken as compared with a conventional Pt-wire and, therefore, a high speed and high sensitivity are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a thermistor-type temperature sensor having a high-speed response temperature-sensing part that has a small heat capacity because the temperature-sensing part is provided in a thin film-like bridge part and can raise the temperature with a small amount of heat. The present invention relates to a temperature sensor devised so that the heat capacity of the temperature-sensing part is made as small as possible and thermistor material of the high-resistance part can also be used.

The present applicant has previously developed a small electric heater for local heating that can be applied to hot-wire anemometers, Villany vacuum gauges, gas detectors, etc., which has a similar structure to the present invention, and which has low power consumption and high-speed response. Electric heaters (for example, Japanese Patent Application No. 54-2755.9)
) was proposed. We also proposed an "optical sensor" with a similar m-frame structure, using a thermistor material in the diaphragm tank building material layer, and an electric heating part, a thermistor material layer, and a gas-sensitive material layer arranged in the bridge part [gas detector]. J' is also proposed.

The present invention provides a temperature sensor in which a thermistor material layer is provided on the thin film suspension part of the comb rack as described above, and this thermistor material layer serves as a temperature sensing part, which can also be combined with an electric heating part. In order to particularly reduce the heat capacity of the bridge, the arrangement of the thermistor material layer is limited within the wIA bridge region, and the conductor layer that serves as the electrode is designed to allow the use of high-resistivity thermistor materials such as amorphous silicon. By sandwiching the thermistor material layer near the center of one frame, it is possible to detect only the resistance in the thickness direction of the thermistor material layer in the area where the conductor layer overlaps, and the temperature rises the most due to current heating or light receiving heating. This invention relates to a temperature sensor that has been improved to be able to effectively detect the temperature near the center of the roof frame.

A detailed description will be given below with reference to the drawings. Figure 1 shows
FIG. 2 is a plan view for explaining an embodiment of the temperature sensor according to the present invention having a structure suitable for, for example, a Villany vacuum gauge, and FIG. 2 is a cross-sectional view taken along the line I-I in FIG.
In the figure, 1 is a polyimide plate, and 2 is a copper foil attached to the polyimide 1 with an adhesive 11. 3 is an electrical insulating layer, for example, a silicon nitride film (S
1s N4 film) and can be easily produced using plasma CVD technology and photolithography technology. 4a14
b is a conductive layer, which is patterned by photolithography so as to remain within the area of the comb portion.
The high resistivity thermistor material layer 5, which is a P-thick amorphous silicon (α layer, referred to as a-5i) layer, is 8! ! Since they are sandwiched near the center of the frame, the electrical resistance seen from the lead wire 9a19b taken out from the conductor layer in both prefectures is a-5 in the overlapping area of the upper conductor layer 4b and lower conductor layer 4a.
It can be regarded as the electrical resistance in the vertical thickness direction of the i-layer 5. Therefore, the temperature sensing portion is considered to be the area where both conductive layers 4a and 4b overlap. a-3i55 is plasma CVD
For example, chromium (C
To make it easier to obtain ohmic contact with the conductor Mlr t a + 4 b, which is made of a double-layer metal conductor of r) and aluminum (AI), both electrode sides are doped with phosphorus (P) to lower the resistance. It's better to do so. In addition, as a thermistor material, it is desirable that the B constant is large, and according to experiments, P
Since the a-5t material that is not doped with P has a larger B constant, P is doped only in a thin layer (for example, 5
00A thick layer).

Since this embodiment is an example of application to a Villany vacuum gauge, a conductor layer 6+ 6al 6bl 5c that generates heat when an electric current is passed is placed in close contact with the underside of the electrical insulating layer 3 on the m-frame part. It is formed on an electrically insulating layer 7 for electrical separation from the foil 2. Conductor layer 6+ 6a+
6b+6c is, for example, C such as a platinum (Pt) sputtered film or a metal silicide such as molybdenum silicide.
It can be formed with a film thickness of about 37L% of the Q of the VD film. 6+
6a+ 6b, ec are integral layers, but the conductor layer 6
Of these, the left and right electrode portions are designated as 1□a and 6b, and the bridge region that generates heat is designated as 60, corresponding to the area from which the lead wires 1Qa and 10b are taken out. When metal silicide is used as the conductor layer 6, the lead wire 10a,
10b, the left and right electrode parts 6a+6b are
It is necessary to form an AI vapor deposition film or the like. 8a+8b are grooves in which the copper foil 2 is removed by etching, and 8C is a groove in which the etching time is lengthened and side etching is actively utilized when forming the grooves 8a and 8b, to improve the strength of the upper multilayer thin film structure. This is the hollow part where the bridge was left and the crocodile was removed and penetrated. The grooves 8a+8b and the hollow portion 8C are created using the lead wire 9'a.
+ 9b; 10a + ], can be easily formed using photolithography technology before drawing out the Ob.

As described above, when the present invention is implemented as a Villany vacuum gauge, the heat capacity of the comb part can be reduced, and since it is in the form of a thin film, the contact area with gas in vacuum is smaller than that of conventional PT wires. Thermistor material can be very large, resulting in high speed and high sensitivity, and a thermistor material with a large B constant can be used independently of the heating conductor layer.
Even if it has high photoconductivity like the a-3i, it has an upper conductor layer made of metal, etc., so the temperature sensing part can be prevented from being exposed to light, and only the thermistor resistance changes due to temperature. It has the advantage of being able to detect

When implementing the present invention as an optical sensor such as infrared light,
The conductive layer 6, the electrical insulating layer 7, and the lead wires 10a+10 that generate heat when energized in FIGS. 1 and 2
b may be removed and a layer such as an all-black layer serving as a light absorbing layer may be placed on the upper conductor layer 4b near the center of the comb section to form a 1c structure. Since the heat capacity of the m-frame section that serves as the light receiving section can be reduced, a high-speed, high-sensitivity thermal optical sensor can be realized.
High sensitivity can be achieved by using a high-resistance thermistor material 5, and even if there is light that cannot be absorbed sufficiently by the entire black layer, it is blocked by the upper conductor M4b. Therefore, there are advantages such as being able to detect only the resistance change accompanying the temperature change of the thermistor material 5 due to light reception.

As is clear from the above rules, according to the present invention, the heat capacity of the comb holder can be made extremely small, so when using heat generated by energization, the power consumption is small, and when using external heating such as light reception, The amount of light received is small,
A temperature sensor with high sensitivity and fast response can be provided.

[Brief explanation of the drawing]

11U is a plan view for explaining an embodiment of the temperature sensor according to the present invention, which is applied to a Villany vacuum gauge, and FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1. be. ±...Polyimide plate, 2...Copper foil, 3
...electrical insulating layer, 4a+4b self-conductor layer,
5...Thermistor material F7, 61 6a+ 6b
+ 6cm...Conductor layer for generating heat when energized, 7...Electrical insulating layer, 8a18b...Groove,
8c...Empty part, 9a l 9b;
toa + 10b, ,, lead wire, 11...
・Cuffix.

Claims (1)

[Claims] 1. In a temperature sensor with a bridge structure in which a temperature sensing part is provided in the bridge part, at least one layer of the thin film-like bridge structure material layer bridging the air gap is formed of an electrical insulating layer 3, A thermistor material layer 5, which is a temperature-sensitive material, is arranged in the bridge region of the electrical insulating layer 3, and the thermistor material layer 5 is sandwiched between the upper conductor layer 4b and the lower conductor layer 4a near the center of the bridge. A temperature sensor characterized in that the electrical resistance of the thermistor material layer 5 in the thickness direction in the overlapping region is detected. 2. Among the thin film-like bridging structure material layers that bridge the void,
2. The temperature sensor according to claim 1, wherein one layer is a conductor layer 6, and by passing a current through the conductor layer 6, the bridge portion generates heat.