JPH03176623A - Temperature controller for semiconductor element and temperature sensor used for the same - Google Patents

Abstract

PURPOSE:To measure temperature more accurately and sensitively by providing a temperature sensor composed of an insulating substrate, a couple of amorphous semiconductor thin films, a couple of thin film resistance bodies, and two couples of ohmic electrodes, the semiconductor element, an electron cooling element, and a temperature controller. CONSTITUTION:The temperature sensor 10 is constituted by making bridge connections between the couple of amorphous semiconductor thin films 2 which have large resistance value-temperature characteristics and the couple of thin film resistance bodies 3 using thin film materials with small resistance value-temperature dependency on an insulating substrate 1 which has an extremely fast heat response speed through the two couples of ohmic electrodes 4a - 4d. The temperature controller includes the temperature controller 13 and temperature sensor 10 and supplies a current controlled by the electron cooling element 12 to control the temperature of the semiconductor element 11. The semiconductor element 11 is a light receiving element, a light emitting element, etc., and stable, high-accuracy operation is realized for the 1st time in good temperature control. Then this temperature sensor 10 has the fast heat response speed, so the temperature control to specific temperature is accurately and stably carried out.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a temperature control device for semiconductor elements, which operates electronic devices, particularly semiconductor elements such as photodiodes and laser diodes, with constant and high precision. , and a temperature sensor used therein. For example, a fast thermal response rate is required to sensitively and accurately measure temperature.

In addition, in optical measuring devices such as dimension measuring instruments using semiconductor elements and optical fiber break point measuring instruments, fluctuations in light receiving sensitivity and oscillation frequency due to the temperature of the light receiving element and light emitting element lead to deterioration of measurement accuracy. It is necessary to operate a semiconductor element in a constant temperature state. This invention is intended to be used for these purposes.

[Conventional technology]

Temperature sensors include platinum thermometers, thermistors, thermocouples,
IC temperature sensors, temperature sensors using SiC and diamond, and the like have been used or proposed, but each has the following drawbacks.

(1) Platinum thermometer ■ The structure of the resistance element is complicated and the shape is large, making it impossible to miniaturize. For example, even with a thin-film platinum temperature sensor, since platinum has a high conductivity of about 9 x 10' (S-c river-1), a flat plate type sensor has a size of 10 length x 3 width x 0.6 height (between units).
, cylindrical type, diameter 1.6 x length 13 (unit: n+m)
Only a small amount of miniaturization is possible.

■ A compensating conductor is required between the platinum thermometer and the measuring device. This is because the platinum temperature measuring element is one of the resistors in the bridge circuit and is located in the temperature measuring section, while the other three reference resistors are located within the measuring device.

■ Response speed is slow. This is because the thermal conductivity of Teflon or glass covering platinum is low, and the heat capacity is large due to the large shape.

(2) Thermistor ■ Cannot be made thinner or smaller.

■ Response speed is slow. This is because the thermal conductivity of the glass or epoxy coating the thermistor is low, and the heat capacity is large due to the large shape.

■ Heat dissipation is small and measurement temperature errors are likely to occur.

(3) Thermocouple■ It was difficult to integrate the reference junction in the same temperature sensor.

■ It was necessary to consider errors in the reference junction and compensation conductor.

■ Measurement near room temperature was difficult.

(4) IC-based temperature sensor ■ The temperature characteristics of the current flowing between the base and emitter are utilized, and the non-linearity is large, requiring a circuit to correct this, making it difficult to miniaturize.

■ Since the sensor section could not be made smaller, the capacitance was large and the response speed was slow.

(5) Temperature sensor using SiC and diamond ■ High quality SiC and diamond can only be deposited on limited substrates such as Si single crystal substrates, and these substrates are difficult to thin film during wafer process. Therefore, it was not possible to increase the thermal response speed.

(2) SiC and diamond have slow deposition rates, cannot be made into large areas, and have poor in-plane uniformity, making it difficult to reduce costs.

As described above, it has been difficult to obtain a temperature sensor that has a fast thermal response speed, is compact, has a large temperature detection voltage, is highly accurate, and is inexpensive. On the other hand, a technology for a temperature sensor that utilizes the resistance-temperature characteristics of an amorphous semiconductor is disclosed in Japanese Patent Application Laid-Open No. 52-58579 (Temperature Detector).
It is disclosed in JP-A-53-44072 (sensing element) and JP-A-58-170001 (temperature sensing device).

However, none of these publications specifically discloses a technique for increasing the thermal response speed of a temperature sensor. For example, JP-A No. 52-58579
The publication only discloses a temperature sensor that utilizes the output voltage temperature dependence at the connection point when a thermistor with a large heat capacity and a thermistor with a small heat capacity are connected in series. There is no disclosure of sensitive and precise measurements. Also, Tokukai Showa 5th
3-44072 also discloses only a temperature sensor that utilizes the fact that the voltage between amorphous semiconductor electrodes depends on temperature. Furthermore, in Japanese Patent Application Laid-open No. 58-170001 (temperature sensing device) by the same applicant,
This disclosure only relates to a bridge-connected temperature sensor using an amorphous semiconductor.

As mentioned above, none of the inventions discloses a technology for increasing the thermal response speed of a temperature sensor. A thermoelectric cooling element such as a Peltier element was used.The thermoelectric cooling element controls the current of the thermoelectric cooling element using a signal representing the surface temperature of the element, thereby controlling the temperature of the semiconductor element. . As a temperature sensor for measuring surface temperature, there has been a demand for a temperature sensor that has a fast thermal response speed, is compact, has a large temperature detection voltage, is highly accurate, and is inexpensive. Also,
A resistor with a large resistance temperature coefficient is installed in the temperature measurement part,
Because a reference resistor with a small degree coefficient is installed inside the measuring device, there are problems with temperature measurement errors due to temperature changes within the measuring device and noise between the wiring between the temperature measuring part and the measuring device. was there. In order to solve this problem, it has also been required to integrate the temperature sensor and the reference resistor. However, in conventional inventions, high-precision operation of semiconductor elements has been achieved through stable temperature control obtained by increasing the thermal response speed of the temperature sensor and integrating the temperature sensor and the resistor for the base. There was no disclosure of specific technology for obtaining this information.

[Problem to be solved by the invention]

The combination of amorphous semiconductor thin film and a thin film resistor with a small temperature coefficient of resistance, which combines a fast thermal response speed obtained by reducing both thermal resistance and heat capacity, and a thin film type that is significantly smaller. It is an object of the present invention to obtain a high-precision, inexpensive temperature sensor that has a large temperature detection voltage due to a bridge connection, and to configure a temperature control device for a semiconductor element using the temperature sensor.

[Means to solve the problem]

This invention enables a three-layer semiconductor process, typically photoetching, even though the substrate with high thermal conductivity is extremely thin, making it possible to obtain low thermal resistance and heat capacity, resulting in fast A temperature sensor can be obtained by connecting an amorphous semiconductor thin film and a thin film resistor with a small temperature coefficient of resistance, which provides a high thermal response speed and satisfies the performance as a temperature sensor for temperature measurement of a temperature control device. Based on the fact discovered by the inventor that

Taking advantage of this fact, ``the above-mentioned amorphous semiconductor thin film and a thin film resistor with a small resistance temperature coefficient are placed on an insulating substrate made of a good thermal conductor or a metal substrate covered with an insulating film. We have realized a bridge-structured temperature sensor that is small and has a thermal response speed that is unprecedentedly fast, and a temperature control device for semiconductor devices that uses this temperature sensor.

[Effect]

In this invention, the thermal conductivity of the substrate forming the temperature sensor formed by the bridge connection of the amorphous semiconductor thin film and the thin film resistor with a small resistance temperature coefficient is at least 20 (J/
III.5-K) or more, and its thermal resistance is at least IXIO''<K/J-s) or less.

Moreover, its heat capacity is at least lXl0~'(J#)
It is as follows. As a result, the thermal response speed of the temperature sensor is at least I x 10-' (s) or less. Also,
The temperature dependence of the resistance value of the amorphous semiconductor thin film that forms the bridge connection is at least 0.4 (X/K) at conductivity of 30 (S-cm-') or more, and the detection voltage of the temperature sensor is , at least 1 (mV/K) or more. The resistance value due to the bridge connection is at least about 0.25 (kΩ) or more, and the power consumption is at least l 2 (mW) or less.

Further, the resistance value thereof is at least about 10 (kΩ) or less, and is hardly affected by noise in the amplifier.

〔Example〕

FIG. 1 is a conceptual diagram of a temperature sensor according to the present invention. This invention provides a pair of amorphous semiconductor three films 2 having a large resistance value temperature characteristic and a resistance value temperature dependence on an insulating substrate 1 having an extremely fast thermal response speed or a metal substrate 1 coated with an insulating film. A pair of thin film resistors 3 made of a small thin +1i material are connected to four ohmic electrodes 4a, 4b, 4c,
4d, and is characterized by an extremely fast thermal response speed.

Table 1 is a table showing the thermal response speed of temperature sensors, and shows the conventional one and the one of the present invention. The formula for thermal response speed is also shown.

Table 1 Thermal Response Speed - Thermal Resistance x Heat Capacity As can be seen from Table 1, the thermal response speed of the temperature sensor according to the present invention is significantly faster than other sensors.

Furthermore, conventional temperature sensors, such as platinum thermometers, are large and cannot measure the temperature of minute parts. However, in the present invention, by using a semiconductor thin film process typified by photolithography, 0.85
It has been miniaturized to less than X O,85 (unit 111), making it possible to measure the temperature of minute parts.

Next, a method for manufacturing the temperature sensor will be explained. The material for the insulating substrate or the metal substrate 1 whose surface is covered with an insulating film (hereinafter collectively referred to as the insulating substrate) has a high thermal conductivity of 20 (J/++-s) or more. , thickness 5
It is desirable that it be extremely thin, about 0 (μa+). When using a metal substrate, the reason why the surface is covered with an insulating film and the thickness of the substrate is made thin is to increase the thermal response speed of the temperature sensor.

Furthermore, in order to withstand the semiconductor thin film process, it must have resistance to redox atmospheres and acids and alkalis, and heat resistance. Therefore, alumina substrate, BN substrate, SiC substrate, 5iJ4 substrate, AIN substrate and BeO
A substrate or the like is used. After thoroughly cleaning the insulating substrate 1 with an organic solvent or the like, it is dried in a clean atmosphere.

Next, using a gas such as 31841 GeH4, plasma C
By the VD method, a-3i: H5a-Ge: H,
a-3i: Deposit an amorphous semiconductor thin film such as Ge.

At this time, in order to control the conductivity of the thin film deposited, the discharge power and substrate temperature are changed, or PHs and AsH3 are used for n-type semiconductors, and Bffi is used for p-type semiconductors.
A common method is to change the supply amount of doping gas such as H6.

Unnecessary portions of the deposited amorphous thin film semiconductor are removed using photoetching technology to form a predetermined resistor (amorphous semiconductor thin film 2). This resistor is a variable resistor.

Subsequently, unnecessary portions of the thin film of tantalum nitride, nichrome, silicon germanium, etc. deposited by sputtering, vacuum evaporation, or CVD are similarly removed to form a predetermined resistor (thin film resistor 3). This resistor is a thin film fixed resistor with a small temperature coefficient of resistance. Further, a metal thin film for electrodes such as gold is deposited, and unnecessary portions are similarly removed to form predetermined electrodes 4a, 4b, 4c, and 4d (ohmic electrodes). Note that as the surface protective film, a Si0g thin film, an s+J4 thin film, or the like is used. the result,
A temperature sensor with a bridge-connected circuit using the amorphous semiconductor thin film shown in FIG. 1 is obtained.

In order to realize the temperature sensor of the present invention, the following three
Two major technical issues needed to be solved. Therefore, the above-described temperature sensor solves these problems. That is, the first is that the temperature sensor itself has a fast thermal response speed in order to measure temperature sensitively and accurately.

The thermal response speed is determined by the formula shown in Table 1. As can be seen from this equation, the thermal response speed is determined by the product of thermal resistance and heat capacity. Among these, thermal conductivity in particular varies greatly depending on the material, and the thermal response speed is proportional to the "length", that is, the square of the film thickness of the substrate. It is important to make it thin.

From this, the thermal conductivity of the substrate is 20 (J/a+-s
・High K) with a density of 3 to 4 x 10” (g/rrr
), an aluminum substrate with a specific heat of 0.5 to 1 (J/g-K), a BN substrate + SiC substrate, a 5i3Nn substrate,
When a temperature sensor was formed using an AIN substrate, a BeO substrate, etc., it was experimentally confirmed that the thermal response speed was faster than that of a conventional platinum temperature sensor, and the calculated value of the thermal response speed was 0.
．． 1 (S) (s) or less. Furthermore, the fastest thermal response speed was 3 x 10-' (s).

By selecting the substrate material and shape from the calculation formula in this way, we were able to obtain a significantly faster thermal response speed than before.

Second, although the bridge connection bias voltage is as low as 0.5 (V), the detection voltage of the platinum thermometer is 0.8 (mV/mV).
K): A detection voltage of 61 (mV/K) or more can be obtained.

FIG. 3 shows a circuit diagram of the bridge connection used in the present invention and an equation for the temperature detection voltage V2O. Bias voltage V.

At 0.5 (V), at least the temperature detection voltage 1
(mV/K) or more, the temperature coefficient of resistance of the amorphous semiconductor thin film that is the variable resistor must be 0.4 (χ/
K) Although above is necessary, in the present invention, plasma CV
Even though the conductivity was as high as 30 (S-cm −' ) or more by method D, a film with a conductivity of 0.4 (χ/K) or more could be obtained.

FIG. 4 shows an example of resistance temperature characteristics. The horizontal axis shows the reciprocal of the absolute temperature on a linear scale, and the vertical axis shows the resistance value R on a logarithmic scale. FIG. 5 shows the temperature T and detection voltage V of a temperature sensor using a resistor that matches the resistance value/Iq characteristic shown in FIG.
. It is a graph of uL. A constant voltage is biased to the electrodes 4a and 4d, and the electromotive force between the electrodes 4b and 4c is used as the temperature detection voltage. As shown from this graph, it was confirmed through experiments that the temperature detection voltage was 1 (mV/K) or higher, had almost linear characteristics, and had reproducibility.

Furthermore, since the bias voltage is as small as 0.5 m, power consumption is as low as 0.08(1), and measurement errors due to heating of the temperature sensor are small. Temperature sensor power consumption 0.08 (mW
) is the value of 175 of the platinum power consumption 0,4 (mW).

Third, the resistance value of the resistor forming the bridge connection can be set within an appropriate range for use as a temperature sensor. When the resistance value of the resistor is small, the power consumption of the temperature sensor is proportional to the square of the bias voltage and inversely proportional to the resistance value. When the bias voltage is 0.5 m, for example, in order to suppress the power consumption of the platinum thermometer to 0.4 (mW) or less, the resistance (JI value is at least 0.625) is required.
(kΩ) or more, it must be discarded. Further, in order to reduce the power consumption to less than 1 (n+W), for example, the resistance value must be at least 0.25 (kΩ) or more. On the other hand, when using the temperature detection voltage in an electric circuit,
Considering the influence of noise during amplifier amplification, the resistance value is preferably about 10 (kΩ) or less. The present invention has created a temperature sensor that satisfies these conditions.

By solving the above three technical issues, a temperature sensor with a fast thermal response speed was realized.

FIG. 2 shows an embodiment of a temperature control device 2o for a semiconductor device 11 according to the present invention.

The temperature control device 20 according to the present invention includes a temperature controller 1
3 and a temperature sensor 10, and a controlled current is passed through an electronic cooling element (Peltier element) 12 to cool the semiconductor element 1.
This is to control the temperature of 1. Here, semiconductor element 1
1 is a light-receiving element or a light-emitting element, etc., and by controlling the temperature well, it has achieved extremely stable and high-speed operation. Since this temperature sensor 10 has a fast thermal response speed, temperature control at a predetermined temperature is more precise and
I am now able to bend more stably. Furthermore, in order to obtain temperature stability of at least ±10 (mK) or less, the detection voltage of the temperature sensor is required to be 1 (mV/K) or more. It was confirmed that the temperature could be controlled satisfactorily using this method. Furthermore, because the power consumption of the temperature sensor is low, temperature measurement errors can be reduced. Furthermore, since the influence of noise during amplifier amplification of the temperature detection voltage is small, temperature control can be performed more accurately.

〔Effect of the invention〕

The present invention provides an insulating substrate made of a good thermal conductor or a metal substrate whose surface is covered with an insulating film, and which is made of an amorphous semiconductor resistor and a low temperature coefficient resistor. Since the temperature sensor is small and has a bridged structure with a thermal response speed that is faster than ever seen before, it has the following unique effects.

(1) Since the thermal response speed of the temperature sensor can be made as fast as 0.1 (s) or less, more precise and sensitive temperature measurements can be made.

(2) Despite the fact that the amorphous semiconductor thin film used to bridge the temperature sensor has a high electrical conductivity of 30 (S-cm −') or more,
Since the temperature coefficient of resistance value is as large as 0.4 (X/K) or more,
The temperature detection voltage is as high as 1 (mV/K) or more, allowing accurate temperature measurement.

(3) The resistance value of the temperature sensor is 0.25 (kΩ) to 10
(kΩ), the power consumption is small, and the temperature is not easily affected by amplifier noise, allowing accurate temperature measurement.

(4) The minimum shape of the temperature sensor is 0.85X O, 85
(Unit: M) Because it is compact, it is possible to measure the temperature of minute parts.

(5) An amorphous semiconductor thin film can be deposited using a simple and inexpensive device, has a fast deposition rate, can be made into a large area, and has excellent in-plane uniformity, so a cheaper temperature sensor can be manufactured.

(6)? The 5 degree sensor process is compatible with the semiconductor device process, so it can be incorporated into a part of the semiconductor device to measure temperature.

(7) Due to the stable temperature control obtained as a result of the effects of the invention described above, a highly accurate operation of ±10 (mk) has become possible by stabilizing the temperature of the semiconductor element.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a temperature sensor, Fig. 2 is an example of a temperature control device for semiconductor elements, Fig. 3 is an expression of the detection voltage of the temperature sensor and an open circuit diagram, and Fig. 4 is an amorphous FIG. 5 is a graph of the temperature T of the temperature sensor and the detected voltage. In the figure, l is an insulating substrate (or a metal substrate whose surface is covered with an insulating film), 2 is a resistor made of an amorphous semiconductor thin film, 3 is a thin film resistor having a drag coefficient, 4a, 4b+
4c, 4d are ohmic electrodes forming a bridge connection, 10
11 represents a temperature sensor, 11 represents a semiconductor element, and 12 represents an electronic cooling element.

Claims (1)

[Scope of Claims] 1) An insulating substrate (1) and a pair of amorphous semiconductor thin films (2) having a large temperature coefficient of resistance formed on the substrate to form opposite sides of a bridge connection. ) and a pair of thin film resistors (3) with a small resistance temperature coefficient, and a pair of ohmic electrodes (4a) connecting the amorphous semiconductor thin film and the thin film resistor.
, 4b, 4c, 4d); a semiconductor element (11); and an electronic cooling element (12) that is in contact with the electronic cooling element through a thermally conductive material; A temperature control device for a semiconductor device, comprising: a temperature controller (13) that controls the temperature of the semiconductor device by flowing a controlled current. 2) an insulating substrate (1); a pair of amorphous semiconductor thin films (2) with a large temperature coefficient of resistance formed on the substrate to form opposite sides of a bridge connection; a pair of small thin film resistors (3); two pairs of ohmic electrodes (4a) connecting the amorphous semiconductor thin film and the thin film resistor;
, 4b, 4c, 4d), wherein the temperature sensor has a thermal response speed of 0.1 (s) or less.