JPH0663852B2 - Non-contact type semiconductor temperature sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention utilizes heat that detects the temperature of a temperature-measuring object in a non-contact manner by utilizing the fact that the electric resistance of a sensor part changes due to a temperature rise due to light absorption. The present invention relates to an effect-type temperature sensor, and more particularly to a non-contact type semiconductor temperature sensor having a sensor part in a suspended state.

[Prior Art] A non-contact type temperature sensor that measures the temperature of a temperature-measuring object in a non-contact manner receives light (infrared ray) that is thermally radiated corresponding to the temperature of the temperature-measuring object itself and absorbs the light. It measures temperature by converting temperature changes due to changes in resistance and is generally called a thermal effect infrared temperature sensor (porometer). The sensitivity of the sensor part is given by the ratio of the resistance increase to the temperature increase, but in the past, as a substance with a large ratio, for example, F
Oxides such as e, Co, Ni and Mn are used.

Conventionally, as this type of non-contact type temperature sensor, as shown in FIGS. 7 (A) and 7 (B), a substrate 1 and an infrared filter are used.
In a container consisting of a light-shielding cap 2 having 2a,
A rectangular thin film temperature measuring sensor body 3 which is laid across the pins 1a and 1b erected on the substrate 1 with metal wires 3a and 3b, and a metal wire between the pins 1b and 1c erected on the substrate 1. 4a, 4b and a rectangular thin film temperature compensating sensor body 4 which is laid horizontally.
Both 3 and 4 are made of the above-mentioned substance in a three-dimensional simple substance, and are suspended in the space between the pins 1a, 1b and 1c. The temperature measuring sensor body 3 is located directly below the infrared filter 2a, and the incident infrared ray that has passed through the filter 2a directly irradiates the temperature measuring sensor body 3. Changes to the resistance value corresponding to the temperature change.
The temperature compensating sensor body 4 is located beside the temperature measuring sensor body 3, is not exposed to the infrared rays from the temperature-measuring body, and changes its resistance in response to only the environmental temperature in the container. Therefore, the temperature of the temperature-measured body with respect to the ambient temperature is measured by the change in the resistance value of the temperature-measuring sensor body 3 relative to the temperature-compensating sensor body 4.

By the way, although the temperature compensating sensor body 4 may be arranged outside the container, the temperature measuring sensor body 3 in a state where infrared rays are not received.
Since the temperature compensation effect (accuracy of environmental temperature) increases as the temperature is closer to the temperature of the sensor itself, the temperature compensation sensor body 4 is arranged in the vicinity of the temperature compensation sensor body 4 in the range where the temperature compensation sensor body 4 is not exposed to infrared rays. ing. Further, the reason why the temperature measuring sensor body 3 and the temperature compensating sensor body 4 are suspended is that the gas in the container is used as a heat insulating material to prevent heat conduction due to contact between solids as much as possible, and the infrared ray once captured. This is because the radiant heat due to Further, the reason why the temperature measuring sensor body 3 and the temperature compensating sensor body 4 are made of the same substance and in the same shape is to make the temperature-resistance characteristics match as much as possible and to improve the measurement accuracy.

[Problems to be Solved] However, the above-mentioned conventional non-contact temperature sensor has the following problems.

Since the temperature-measuring sensor body 3 and the temperature-compensating sensor body 4 are manufactured as separate components, even if the materials are the same, there are variations in the product such as dimensional accuracy of shape and uniformity of internal structure. Since they occur inevitably, the temperature-resistance characteristics are not necessarily the same, and therefore instrumental errors cannot be ignored and measurement accuracy is poor.

When manufacturing the non-contact type temperature sensor, the temperature measuring sensor body 3 and the temperature compensating sensor body 4 are brazed to the pins 1a, 1
The work of disposing and connecting between b and 1c is unavoidable, which takes time and labor, and the product cost is high.

[Object of the Invention] The present invention is to solve the above problems, and an object of the present invention is to make temperature-resistance characteristics of a temperature measuring sensor body and a temperature compensating sensor body equal to each other, and to make an instrumental error associated therewith. It is an object of the present invention to provide a non-contact temperature sensor that can almost completely solve the above problem and can reduce the product cost.

[Means for Solving Problems] In order to achieve the above object, the configuration of the non-contact type semiconductor temperature sensor according to the present invention has the following requirements (1) to (3).

There must be a temperature measuring sensor portion including a resistor having a large resistance temperature coefficient formed on the semiconductor layer and a coating film having a large light absorptance that covers the resistor.

Here, the "semiconductor" means, for example, single crystal or polycrystalline silicon. The “resistor having a large temperature coefficient of resistance” includes, for example, an Au diffuser. The “coating film having a high light absorption rate” includes, for example, a coating film of Au black, Pt black or the like.

There is a temperature compensating sensor part composed of a resistor having a large resistance temperature coefficient formed on a semiconductor layer adjacent to the temperature measuring sensor part and a coating film covering the resistor having a small light absorption coefficient. .

Here, the "semiconductor" means, for example, single crystal or polycrystalline silicon. The “resistor having a large temperature coefficient of resistance” includes, for example, an Au diffuser. The “coating film having a low light absorption rate” includes a coating film of Au, Pt, or the like.

There is a non-contact gap formed between the temperature measuring sensor section, the temperature compensating sensor section, and the peripheral semiconductor layer surrounding them.

Here, "semiconductor" means, for example, silicon. The thickness of each resistor of the temperature measuring sensor unit and the temperature compensating sensor unit is preferably thinner than that of the peripheral semiconductor layer.
The thickness of the peripheral semiconductor layer is equal to that of the base material, for example, the silicon wafer itself, and the thickness of each of the resistors is set to, for example, less than that of the silicon wafer itself.

There is a metal bridge that is installed in the non-contact gap and that supports the temperature measurement sensor unit and the temperature compensation sensor unit in a suspended state with respect to the peripheral semiconductor layer.

Here, the “metal bridge” is composed of, for example, Au, Pt or the like. Further, the “metal bridge” preferably has a pair of bridge portions, for example.

[Operation] According to this configuration, when the infrared rays radiated from the temperature-measured body irradiate the non-contact type semiconductor temperature sensor, the coating film of the temperature-measuring sensor section absorbs and transmits the infrared rays well, so that the lower layer A resistor with a large temperature coefficient of resistance receives the light and changes its resistance value due to the temperature change due to the absorption of light, and the temperature of the adjacent temperature compensating sensor part created in the semiconductor manufacturing technology is also measured. Infrared rays from the body radiate,
Due to the light-shielding effect of the coating film with a small light absorptivity, the resistor film below it does not respond to this, so this resistor responds only to the environmental temperature of the surrounding space near the temperature measuring sensor section and changes its resistance. Will be done. Since the coating film of the temperature measuring sensor unit and the coating film of the temperature compensating sensor unit in the suspended state are made by the semiconductor manufacturing technology, the temperature-resistance characteristics of both are almost completely the same, and the instrument error Highly accurate measurement with almost none is realized.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is an enlarged plan view showing an embodiment of the non-contact type semiconductor temperature sensor according to the present invention.

FIG. 2 is an enlarged cutaway view showing a state cut along the line II-II in FIG.

FIG. 3 is an enlarged cutaway view showing a state cut along line III-III in FIG.

The non-contact type semiconductor temperature sensor 10 of the embodiment is a silicon substrate.
11, a temperature measuring sensor unit 12, a temperature compensating sensor unit 13, metal bridges 14, 15, 16 and a non-contact gap 17 are roughly configured.

The silicon substrate 11 as a semiconductor is a rectangular chip formed by partitioning a silicon wafer, and has a temperature measuring sensor unit 12
And a non-contact gap 17 defining the temperature compensation sensor portion 13 at the center. The temperature measuring sensor unit 12 and the temperature compensating sensor unit 13 are formed on the silicon substrate 11 so as to be symmetrical and have the same shape.

The temperature measuring sensor unit 12 is divided by a non-contact gap 17 and is formed by Au diffusion on a rectangular single crystal or polycrystalline thin layer silicon substrate, and has an extremely large resistance temperature coefficient.
12a, an insulating film 12b that covers the same, a coating film 12c formed on the insulating film 12c such as Au black or Pt black having a large light absorption rate, and a protective film 12d that covers the coating film 12c. There is. The resistor 12a of the Au diffuser has a very large temperature coefficient of resistance as compared with oxides such as Fe, Co, Ni and Mn.

Further, the temperature compensating sensor unit 13 is divided by a non-contact gap 17, and is formed by Au diffusion on a rectangular single crystal or polycrystalline thin layer silicon substrate. An insulating film 13b covering the same, a coating film 12c formed on the insulating film 13b such as Au or Pt having a small light absorptance (high reflectance), and a protective film 13d covering the same. It is configured.

The non-contact gap 17 separates the adjacent temperature measuring sensor section 12 and temperature compensating sensor section 13 and the peripheral silicon layer 11c surrounding them from each other in a non-contact manner, and the temperature measuring sensor section 12 and the temperature compensating section are separated from each other. Cross section V formed on the sensor section 13 side (front surface side)
The groove 17a is formed by communicating with the recess 17b having a trapezoidal cross section formed on the back surface side of the silicon substrate 11 over the range of these widths.

The metal bridges 14, 15, 16 support one end sides of the temperature measuring sensor unit 12 and the temperature compensating sensor unit 13 in a suspended state, and are made of electrically conductive Au, Pt, or the like. Metal bridge 14,16
Are both the same structure, and a bonding pad portion 14a, 16a formed on the peripheral silicon layer 11c side for bonding an Au wire or the like, and a pair of bridge portions 14b, 16b laid on the non-contact gap 17. And contact portions 14c, 16c made of ohmic material such as AuAs that are electrically connected to the resistors 12a, 13a formed by diffusion on the thin-layer silicon substrate. Metal bridge 15 is metal bridge 1
4, 16 are formed to face each other, and support the other end of the temperature measuring sensor unit 12 and the temperature compensating sensor unit 13 in a suspended state, and are made of electrically conductive Au, Pt, or the like. . The metal bridge 15 has a connecting portion 15a formed on the peripheral silicon layer 11c side.
And a pair of bridge portions 15b, which are installed on the non-contact gap 17 and support the temperature measuring sensor portion 12, and the temperature compensating sensor portion 13.
It is composed of a pair of bridge portions 15c for supporting the electrodes, and contact portions 15d, 15e made of an ohmic substance such as AuAs that are electrically connected to the resistors 12a, 13a.

The temperature measuring sensor unit 12 and the temperature compensating sensor unit 13 are configured as follows.
Only the substances used for forming the coating films 12c and 13c are different, and the other configurations are the same. 18a, 18
b and 18c are insulating films such as SiO ₂ and Si _x N _y .

The non-contact type semiconductor temperature sensor 10 is manufactured by a general semiconductor manufacturing process.

That is, as shown in FIG. 4, first, Au is diffused from the upper surface side of a silicon wafer 19 having a plane orientation (100) to form a substrate having an extremely large resistance temperature coefficient. Where Au
Is easily diffused widely into the silicon wafer 19, so that the silicon wafer 19 becomes a substrate having a large temperature coefficient of resistance almost all over. Next, SiO ₂ , Si _x N _y or the like is deposited on both surfaces of the Au-diffused silicon wafer 19 to form an insulating film, and an opening portion 20a where a V-shaped groove 17a and a recess 17b are to be formed by etching. , 20b of silicon is exposed, and the other insulating films 12b, 18a, 18c are left as etching masks for the silicon wafer 19.

Next, as shown in FIG. 5, a part of the insulating film 12b is etched, and an ohmic material such as AuAs is deposited on the part, and then heat treatment is performed to form contact parts 14c and 15d.
To create. Next, Au black, Pt black or the like is vapor-deposited on the insulating film 12b to form a coating film 12c having a large light absorption rate, and Au, Pt or the like is vapor-deposited on the insulating film 13b to obtain a light absorption rate. A small coating film 13c is formed. The reason for forming the insulating films 12b and 13b is that the coating films 12c and 13c such as Au black, Pt black, Au, and Pt have good electric conductivity, and thus the coating films 12c and 13c.
This is to prevent a short circuit via and to pass all current through the resistors 12a and 13a.

Next, as shown in FIG. 6, S is formed on the coating film 12c and the coating film 13c.
After depositing iO ₂ , Si _x N _{y and the} like to form the protective films 12d and 13d and the insulating film 18b for protecting and insulating them, the metal bridges 14, 15 and 16 are formed by the air bridge technique. Then, by performing etching with an anisotropic etching solution, anisotropic etching is performed from the opening portions 20a, 20b on both front and back surfaces of the silicon wafer 19 in the width direction using the insulating films 18b, 18c as an etching mask. In comparison, as shown in FIG. 3, it travels faster in the depth direction, and has a V-shaped groove 17a having a V-shaped cross section with a smaller width dimension on the front surface side, and the temperature measuring sensor portion 12 and the temperature compensating sensor portion 13 on the rear surface side. A large recessed portion 17b having a trapezoidal cross section is formed over a wide area, and these are communicated with each other to form a non-contact gap 17. As a result, the resistors 12a and 13a as thin-layer silicon substrates are isolatedly formed with respect to the peripheral silicon layer 11c. Sensor part 12 for temperature measurement and sensor part for temperature compensation
13 is separated from the peripheral silicon layer 11c in an island shape with a non-contact gap 17, and is simply supported by the metal bridges 14, 15 and 16 in a suspended state. After that, each chip is cut into small pieces, and the non-contact type semiconductor temperature sensor 10 is completed.

Here, when forming the non-contact gap 17, the insulating film on the surface side
The opening portion 20a formed by the openings 18a and 18b is narrow, and insulation on the back side is
Since the blind opening portion 20b by 18c is wide, the non-contact gap 17 can be made narrower, so that the temperature measuring sensor unit 12 and the temperature compensating sensor unit 13 can be arranged close to each other, and the temperature compensating action can be achieved. The thickness of the resistors 12a, 13b created as a result of double-sided etching is very small and the volume of the temperature measuring sensor unit 12 and the temperature compensating sensor unit 13 is reduced as much as possible. Since it can be made smaller, the response of the measurement is improved, and the weight reduction contributes to increase the supporting safety factor of the metal bridges 14, 15 and 16. In addition, the landing portions of the bonding pad portions 14a, 15a, 16a of the metal bridges 14, 15, 16 are edges where a sufficient supporting strength of the peripheral silicon layer 11c is still secured by adopting anisotropic etching. Since it is in the part, it is not necessary to take long the bonding pad parts 14a, 15a, 16a in order to have bonding strength, and since the non-contact gap 17 is narrow, the bridge parts 14b, 15b, 15c, 16b are also short. Therefore, the metal bridges 14, 15, 16 can be shortened as a whole, and the resistance loss can be reduced. Further, since the support by each metal bridge 14, 15, 16 is a double support structure via a pair of bridge portions 14b, 15b, 15c, 16b, the temperature measuring sensor unit 12 and the temperature compensating sensor unit are provided.
It is possible to effectively prevent the twist of 13 and the like.

In the above embodiment, since the area of the non-contact type semiconductor temperature sensor 10 is small, the infrared rays radiated from the temperature-measuring body are both radiated to the temperature-measuring sensor section 12 and the temperature-compensating sensor section 13. However, the irradiation infrared ray is the coating film of the temperature measuring sensor unit 12.
Since it is well absorbed and transmitted by 12c, the resistor 12a of the lower layer having a large temperature coefficient of resistance receives the light and the resistance value changes due to the temperature change due to the light absorption. Infrared rays from the temperature-measured body are also radiated to the adjacent temperature-compensating sensor portion 13 created in the semiconductor manufacturing technology, but due to the light-shielding effect due to the presence of the coating film 13c having a small light absorption rate, the lower layer This resistor 13a is not sensitive to this, so this resistor 13a
Means that the resistance changes only in response to the environmental temperature of the space around the temperature measuring sensor unit 12 (that is, the temperature of the temperature measuring sensor unit 12 itself when infrared rays are not received).
The temperature of the temperature-measured body with respect to the ambient temperature can be measured with high accuracy by the change in the relative resistance value of the temperature-compensating sensor body 12.

Since the resistors 12a and 13a are simultaneously formed in the same chip by Au diffusion, the film thickness and the internal texture state are uniform and almost completely equal. Therefore, the temperature-resistance characteristics of both are almost the same, and the instrument error Is very small and high precision measurement can be realized. Further, since the temperature compensating sensor unit 13 is disposed closer to the temperature measuring sensor unit 12 due to the semiconductor manufacturing process, the temperature compensating sensor unit 13 is arranged closer to the temperature measuring sensor unit 12.
Since the ambient temperature of itself can be measured more accurately, the accuracy of measurement of the radiation temperature of the temperature-measured body based on the ambient temperature is improved. The temperature compensating sensor unit 13 is formed on the thin-layer silicon substrate together with the temperature measuring sensor unit 12, and the metal bridges 14, 15,
Since it is supported in a suspended state by 16, the chip-shaped non-contact type semiconductor temperature sensor 10 that has been created may be attached directly to an appropriate envelope or the like, and the temperature compensation sensor unit 13 for temperature measurement. It is not necessary to braze the sensor section 12 in a suspended state with a gold wire or the like. The bonding pad portions 14a, 15a, 16a
The terminals can be easily connected with a gold wire or the like. Since the temperature measuring sensor unit 12 and the temperature compensating sensor unit 13 are formed on the thin resistors 12a and 13a due to the presence of the recess 17b, the heat capacity can be made smaller than in the conventional case, and the response characteristics are improved. It Also, due to the presence of thin resistors 12a, 13a. Since the temperature measuring sensor unit 12 and the temperature compensating sensor unit 13 can be further reduced in weight, durability is ensured in the suspension support by the metal bridges 14, 15, 16 and high vibration resistance and the like. Further, since the chip-shaped non-contact type semiconductor temperature sensor 10 is smaller and lighter than the conventional one, it is easy to assemble it in the right place at the right material, and the restrictions on the place of installation are eased, and the application is expanded. Further, the conventional temperature measuring sensor body and temperature compensating sensor body have a single three-dimensional shape, the ratio of the infrared light receiving area to the volume of the constituent material is very small, and the heat capacity is unnecessarily large. Since the resistors 12a and 13a of the temperature measuring sensor unit 12 and the temperature compensating sensor unit 13 are thin films and the ratio is extremely large, the response characteristic is greatly improved also from this aspect.

The non-contact type semiconductor temperature sensor 10 according to the embodiment,
Although the temperature compensating sensor unit 13 is included, in temperature measurement when the environmental temperature does not fluctuate significantly or can be ignored, the temperature compensating sensor unit 13 is not included and only the temperature measuring sensor unit 12 is non-contact. It goes without saying that a semiconductor temperature sensor of the type can be constructed and used.

[Effect of the Invention] As described above, in the non-contact semiconductor temperature sensor according to the present invention, the temperature measuring sensor unit and the temperature compensating sensor unit adjacent thereto are for non-contact with the peripheral semiconductor layer. It is formed on each of the separated and independent semiconductor layers with a gap, and both sensor parts are supported in the suspended state by the peripheral semiconductor layer by the metal bridge that straddles the non-contact gap. Produce an effect.

Since the resistors having a large temperature coefficient of resistance of the temperature measuring sensor part and the temperature compensating sensor part can be formed at the same time by the semiconductor manufacturing process, the accuracy of the temperature-resistance characteristics is assured to be high. Therefore, there is almost no mechanical error as a temperature measuring sensor, and the accuracy of measurement is greatly improved. If each of the resistors of the temperature measuring sensor unit and the temperature compensating sensor unit is made of Au diffuser, a sensor having extremely high sensitivity as compared with the conventional one can be realized.

In the semiconductor manufacturing process, the temperature measuring sensor and temperature compensating sensor can be arranged and the metal bridge can be formed. Therefore, it is not only excellent in mass productivity, but also complicated hanging work using gold wire etc. Is unnecessary, and the manufacturing cost is low. Further, since it can be mounted on an envelope or the like, and because it is small and lightweight, the restriction on the place where the sensor is incorporated is relaxed, so that the non-contact temperature sensor has versatility.

The temperature compensating sensor itself is formed by a semiconductor manufacturing process in a smaller area than before, and the presence of a coating film with a low light absorptivity that covers the resistor with a large temperature coefficient of resistance allows for temperature compensation. Since the sensor unit can be disposed closer to the temperature measuring sensor unit than in the conventional case, the radiation temperature can be measured with higher accuracy based on the environmental temperature of the temperature measuring sensor unit.

Each of the resistors, which have a large temperature coefficient of resistance of the temperature measuring sensor and the temperature compensating sensor, has an extremely large ratio of the radiation receiving area to the volume of the constituent material and a small heat capacity, so the response characteristics are improved. The rise at the start of measurement is fast, and sensitive follow-up measurement of the temperature change of the temperature-measuring object itself is possible. In addition, when the thickness of the semiconductor layer to be each substrate of the temperature measuring sensor unit and the temperature compensating sensor unit is made thinner than that of the peripheral semiconductor layer, the heat capacity can be further reduced, and the response is further improved. A sensor with improved characteristics can be realized.

[Brief description of drawings]

FIG. 1 is an enlarged plan view showing an embodiment of the non-contact semiconductor temperature sensor according to the present invention. FIG. 2 is an enlarged cutaway view showing a state cut along the line II-II in FIG. FIG. 3 is an enlarged cutaway view showing a state cut along line III-III in FIG. 4 to 6 are enlarged sectional views showing respective states in the manufacturing process of the embodiment. FIG. 7 (A) is a vertical sectional view showing an example of a conventional non-contact type temperature sensor, and FIG. 7 (B) is a plan view thereof. 10 …… Non-contact type semiconductor temperature sensor, 11 …… Silicon substrate, 11c …… Peripheral silicon layer, 12 …… Sensor for temperature measurement, 1
3 ... Temperature compensation sensor part, 12a, 13a ... resistor with large resistance coefficient, 12b, 13b ... insulating film, 12c ... coating film with large light absorption rate, 13c ... Small coating film, 12d, 13d ...
… Protective film, 14,15,16 …… Metal bridge, 14b, 15b, 15c,
16b …… Bridge section, 17 …… Non-contact gap, 17a …… V-shaped groove in cross section, 17b …… Recess with trapezoidal cross section, 18a, 18b, 18c ……
Insulating film, 19 ... Silicon wafer.

Claims (4)

[Claims] 1. A temperature measuring sensor portion comprising a resistor having a large temperature coefficient of resistance formed on a semiconductor layer and a coating film having a large light absorptance which covers the resistor, and the temperature measuring sensor. Compensating sensor part composed of a resistor having a large temperature coefficient of resistance formed on a semiconductor layer adjacent to the part and a coating film having a small light absorptance covering the resistor, and the temperature measuring sensor part And a non-contact gap formed between the temperature compensating sensor part and a peripheral semiconductor layer surrounding the temperature compensating sensor part, and the temperature measuring sensor part and the temperature compensating sensor part provided in the non-contact gap. A non-contact type semiconductor temperature sensor, comprising: a metal bridge that supports the semiconductor layer in a suspended state. 2. The non-contact type semiconductor temperature sensor according to claim 1, wherein the resistors of the temperature measuring sensor unit and the temperature compensating sensor unit are Au diffusers. 3. The thickness of each of the resistors of the temperature measuring sensor section and the temperature compensating sensor section is thinner than that of the peripheral semiconductor layer. Non-contact semiconductor temperature sensor. 4. The non-contact type semiconductor temperature sensor according to claim 1, wherein the metal bridge has a pair of bridge portions.