RU2247442C1 - Thermometer system and method for manufacturing data integrated circuit for thermometer system - Google Patents

Abstract

FIELD: heat measuring devices displaying extreme temperature conditions of functional equipment.

SUBSTANCE: proposed thermometer system has data integrated circuit and external measuring circuit. Data integrated circuit has base that carries fast-response and lagging heat-sensing elements built around thermistors mounted on solid-body substrate and used for measuring temperature of medium and wall of location under check, respectively, as well as power leads for connecting heat-sensing elements to external measuring circuit. The latter is provided with comparison unit and display unit. Fast-response heat-sensing element is connected to first input of display unit and lagging one, to second input of comparison unit. Substrate is made of semiconductor material. Newly installed in external measuring circuit are adder as well as first and second transducer amplifiers. Fast-response heat-sensing element is connected to first input of comparison unit and to that of adder through first transducer amplifier. Lagging heat-sensing element is connected to second input of comparison unit through second transducer amplifier. Comparison unit output is connected to second input of adder and output of the latter, to input of display unit either directly or through switching unit. Method for manufacturing data integrated circuit includes formation of thermistors of fast-response and lagging heat-sensing elements on solid-body substrate, attachment of heat-sensing elements to integrated circuit base, and their connection to power leads of external measuring circuit. Thermistors are formed by applying thermistor layer onto semiconductor substrate followed by forming microprofiles. Metal is deposited on contact pads and the latter are connected to respective heat-sensing elements. Substrate section to suit location of fast-response heat-sensing element is removed or blind hole is etched therein and contact pads are connected to power leads embedded in integrated circuit base.

EFFECT: enhanced descriptiveness and sensitivity of target part; reduced size.

3 cl, 5 dwg, 2 tbl

Description

The invention relates to the design and production technology of heat measuring devices based on elements of microelectronics. It is most effective to use them to indicate the extreme temperature conditions for the functioning of various objects, for example, in case of explosion, fire, emergency overheating or hypothermia, etc.

Known temperature measuring system (TS), containing channels for measuring temperature and temperature difference at several points of the controlled object, connected to the amplifier-converter using a key block controlled by the controller. The system further comprises a computing unit for processing measurement results and an indication unit (RU 2025675, G 01 K 3/08, 1994).

However, this system is difficult to configure due to the need to develop algorithms and programs for the functioning of the computing unit. In addition, it is insensitive to highly dynamic thermal processes, since it does not contain information about the rate of change of temperature.

A TS is also known, which contains two channels for measuring temperature with the help of thermosensitive elements (TFE), which have different static characteristics, and a comparison unit with a functional converter that distinguishes the difference of the signals of the TFE. In this case, thermocouples were used as TECs, the hot junctions of which are located in one isothermal zone of the research object, and the cold junctions are in the other isothermal zone of the research object (RU 1658710, G 01 K 3/08, 1995).

This TS is also difficult to configure, and its output signal (temperature difference of isothermal zones) has low information content, since it does not take into account the dynamics of the thermal process.

Closest to the claimed one is a TS containing an information microcircuit and an external measuring circuit in which the information microcircuit includes a base attached to the base with low inertia and inertial TFE based on thermistors mounted on a solid substrate with the ability to measure the temperature of the medium and the walls of the controlled room, respectively, and electrical leads for connecting the HSE to an external measuring circuit, and the external measuring circuit is equipped with a comparison unit and an indicator unit and, moreover, the low-inertia TEC is connected to the first input of the comparison unit, and the inertial TEC is connected to the second input of the comparison unit. As the substrate material, epoxy is used. The difference in the inertia of the TEC in this system can be achieved by combining the mass of one of the TEC with the mass of the device or the wall of the controlled room, the different masses of the used substrates and other elements of thermal insulation, as well as the installation of low-inertia TEC directly in the environment of the controlled room (JP 2001-299253, G 08 B 17/00; US 20030063005, G 08 B 17/00, 2003). Here, the instantaneous signal of the temperature difference between the medium and the case of the controlled apparatus or room is recorded at the output according to the formula:

where ΔТ is the difference signal received at the output of the comparison element;

T ₁ - the temperature of the medium of the controlled object;

T ₂ - wall temperature of the controlled object.

The value of ΔТ under conditions of different thermal inertia TEC contains information about the rate of change of the temperature of the medium. In the steady state ΔТ = 0.

The disadvantage of this system is its low information content for control purposes (for example, fire fighting), since control systems by the rate of change of a physical factor are inoperative due to their instability, which is well known.

The technical task of the proposed device is to increase the information content and ensure the possibility of its use to control a controlled process.

The solution to this problem lies in the fact that in a TS containing an information microcircuit and an external measuring circuit, in which the information microcircuit includes a base, low-inertial and inertial TFEs attached to the base, based on thermistors mounted on a solid substrate with the ability to measure the temperature of the medium and the wall of the controlled room, respectively, and electrical leads for connecting the HSE to an external measuring circuit, and the external measuring circuit is equipped with a comparison unit and a unit m display, the quick-response TCE is connected to a first input of the comparator, and the inertial TCE is connected to the second input of the comparator, the following changes are made:

1) a semiconductor material is used as a substrate for thermistors;

2) an adder and first and second amplifiers-converters are additionally installed in the external measuring circuit;

3) low-inertia TEC is connected to the first input of the comparison unit and to the first input of the adder through the first amplifier-converter;

4) inertial TEC is connected to the second input of the comparison unit through the second amplifier-converter;

5) the output of the comparison unit is connected to the second input of the adder;

6) the output of the adder is connected to the input of the display unit directly or through a switch.

In such a system, the difference signal received at the output of the comparison element, which, as in the prototype, contains information about the rate of change of the temperature of the medium of the controlled object, is summed with the information signal of the temperature of the medium. Thus, the information described by the formula enters the display unit:

where X _o - signal at the output of the vehicle;

k is the coefficient of proportionality.

An analysis of formula (2) shows that the output of the proposed vehicle contains proactive information about the temperature of the medium, adjusted for its rate of change. Obviously, when using this information for control purposes, a proportional-differential (PD) algorithm for generating a control action can be implemented, which is the cause-effect relationship of the changes made with the achieved technical result. In this case, the value of the coefficient k, which determines the share of the control action with respect to the derivative, is set in the range from 0.1 to 0.3, as is customary in automatic control systems for PD-action. When using the output signal for informational purposes only, the value of the coefficient k can be set above the specified upper limit.

The implementation of the substrate from a semiconductor material provides not only the possibility of fabricating HFCs and the entire microcircuit using microtechnology methods, which is important both in terms of manufacturability and miniaturization of the structure, and, especially, in relation to reducing the time constant of the low-inertia thermocouple, since the smaller this time constant, the closer the value difference signal ΔT to the instantaneous value of the derivative. In addition, it was experimentally established that the temperatures measured by the HSE of the new microcircuit, unlike the prototype, differ even in the steady state. This allows us to judge the values of the temperature of the medium and the walls of the controlled object not only in dynamic but also in static modes. This property of the information microcircuit is apparently ensured not only by replacing the substrate material, but also by performing low-inertia TEC at the micro level (since the mass determines its thermal inertia).

To increase the information content of the vehicle, its display unit can be made three-channel. In this case, in addition to the information channel described by formula (2), additional information about the temperatures T ₁ and T ₂ can be displayed on the display unit. In this embodiment, the display unit is three-channel, with the adder output connected to the first input of the display unit, the output of the first amplifier-converter is additionally connected to the second input of the display unit, and the output of the second amplifier-converter is additionally connected to the third input of the display unit.

An alternative is the option of connecting a single-channel display unit through a switch installed with the ability to switch information channels. To automate the process of switching the measuring channels, the external measuring circuit additionally contains a timer, the output of which is connected to the control input of the switch.

Since the technical characteristics of the device are determined by the manufacturing technology of the information chip, this technology is declared an independent claim.

The prototype of the method is the patent US 20030063005, G 08 17/00, 2003 in connection with the proximity of the structures of the resulting target products. As can be seen from the description of the prototype, an information circuit for a TS in the known method is produced by forming a low-inertial and inertial TFE on a substrate made of a solid, namely epoxy resin, and they are connected to electrical terminals for connecting the TFE to an external measuring circuit. This method is non-technological (it is not microtechnology, as can be seen from the used substrate material) and does not provide miniaturization of the target product at the microelectronic circuit level, which results in low inertia of measurements and insensitivity to the temperature difference between the medium and the wall of the controlled object in static mode.

The technical task of the proposed method is to miniaturize and increase the sensitivity of the target product.

The solution to this technical problem lies in the fact that in a method of manufacturing an information microcircuit for a TS, involving the formation of thermistors of low inertia and inertial TFE on a substrate made of a solid body, attaching a TFE to the base of the microcircuit and attaching a TFE to electrical terminals for connection to an external measuring circuit, The following changes and additions are made:

1) thermistors are formed by applying a thermoresistive layer to a substrate of semiconductor material with subsequent microprofiling of this layer;

2) perform metallized contact pads and their connection to the corresponding TEC;

3) a substrate section at the location of the thermistor of a low-inertia thermosensitive element is removed or a blind hole is etched in it;

4) the contact pads are attached to the electrical terminals mounted in the base of the information chip.

Figure 1 and 2 shows the functional diagrams of the options for the vehicle;

figure 3-5 presents a diagram of the designs of the main nodes of the options for information chips of the vehicle.

Tables 1 and 2 show the technical characteristics of the vehicle options.

TS (Fig. 1) contains an information microcircuit and an external measuring circuit, in which the information microcircuit includes a low-inertia TEC 1 and an inertial TEC 2 with sensitive elements based on thermistors mounted on a substrate of semiconductor material with the ability to measure the temperature of the medium and the walls of the controlled room, respectively, electrically connected to an external measuring circuit equipped with the first and second amplifiers-converters (items 3 and 4), a comparison unit 5, an adder 6 and a unit 7 Superimpose. In this case, the low-inertia TCE 1 is connected through an amplifier-converter 3 to the first input of the comparison unit 5 and the first input of the adder 6, the inertial TCHE 2 is connected through an amplifier-converter 4 to the second input of the comparison unit 5, the output of the comparison unit 5 is connected to the second input of the adder 6, and the output of the adder 6 is directly connected to the display unit 7. When using a multi-channel display unit 7, the outputs of amplifiers-converters 3 and 4 (indicated by a dotted line) are additionally connected to its information inputs.

The comparison unit 5 selects the difference signal ΔT according to the formula (1), taking into account the value of a given proportionality coefficient k. The adder 6 adds k · ΔT to the temperature value T _{1 of the} medium of the investigated object. Thus, the signal at the output of the adder 6 in the dynamic mode is adjusted for the rate of change of the temperature of the medium. It was experimentally established that even in a stationary state, the temperatures T ₁ and T ₂ recorded by the display unit 7 can vary. This is because in the proposed design of the information microcircuit, the low-inertia TEC 1 actually captures a certain average temperature between the temperature of the medium and the temperature of the case of the object under study. The experimental data confirming this circumstance are given in Tables 1 and 2.

When using a single-channel display unit 7 (Fig. 2), this unit is connected to the output of the adder 6 and amplifiers-converters 3 and 4 through the switch 8. To automatically switch the information channels, a timer 9 is used, which is connected to the control input of the switch 8.

Variants of the design of the information chip are described further in the examples illustrating their manufacture.

EXAMPLE 1. For the manufacture of an information microcircuit, TSs form a low-inertia and inertial TCE 1 and 2 based on discrete thermistors on a substrate 10 (Fig. 3) made of germanium. For this purpose, a dielectric sublayer 11 of AlN 1.0 μm thick is applied to the substrate 10 by high-frequency spraying of Al with a magnetron in a mixture of argon and nitrogen gases at a substrate temperature of 400 ° C. Next, a thermoresistive layer of polycrystalline Si with a thickness of 0.5 μm (not shown in the figures so as not to clutter the drawing) is applied to the sublayer 11 by spraying a polycrystalline Si target with a magnetron in argon at a substrate temperature of 450 ° C, in which polycrystalline Si thermistors 12 are formed and 13 for TCEs 1 and 2, respectively, by microprofiling by chemical etching. Then metallized contact pads 14 and their electrical connections with thermistors 12 and 13 are formed by magnetron deposition of Al followed by photolithography.

The substrate 10 with the deposited elements is cut in the plane aa to separate TCE 1 from TCE 2.

Next, the assembly of the information microcircuit assembly (Fig. 4) is carried out on an insidious base 15, in which, using glass insulators 16, electrical leads 17, 18 and 19 are mounted to connect the information microcircuit to an external measuring circuit. TCE 1 is suspended between the electrical leads 17 and 18 at a height of 2 mm from the base 15 (to ensure its low thermal inertia) on wires 20 of Au with the simultaneous electrical connection of these leads with the corresponding contact pads 14 TEC 1. TEC 2 are glued to the base 15 between electrical pins 18 and 19 and similarly electrically connected to these pins. The elements mounted on the base 15 are closed with a protective cover 21 provided with a metal mesh 22 for heat and mass transfer with the environment. In this design, elements 15-19, 21 are used from the case of microcircuits of the TO-5 series (USA).

The microcircuit is connected to an external measuring circuit made according to Fig. 1 with a coefficient k (see formula 2) equal to 1.0, and tested on a model of equipment operating in ordinary and extreme temperature conditions of the medium when controlling the temperature of the medium with a relative reduced error 1-3%. The tests are carried out at initial temperatures of 20 to 250 ° C. The dynamic mode is created by increasing the task of the thermostat by 30 ° C. The values of temperatures T ₁ and T ₂ measured by low-inertial and inertial TEC 1 and 2, as well as the maximum value of the signal X _o , taken from the display unit 7 are fixed.

The test results are shown in table 1. As can be seen from the table, in the steady state, the temperature T _{2 is} less than T ₁ by 1-4 ° C, which indicates the presence of a difference in the temperature of the medium and the housing in the static, and therefore it is advisable in appropriate situations to make decisions taking into account the values indicated temperatures. The table also shows that in dynamic mode, the maximum value of X _{o is} significantly (9-16 ° C) higher than the temperature that was established at the end of the transition process caused by an abrupt (30 ° C) increase in the set value of the temperature controller. Therefore, in the dynamic mode, the pre-emptive output signal X _o is removed, which can be used to timely suppress the emergency state of the object.

EXAMPLE 2. For the manufacture of an information microcircuit (Fig. 5), TSs are formed with low-inertia and inertial TFEs 1 and 2 on the basis of integrated thermistors on a substrate 10 made of silicon. For this purpose, a dielectric sublayer 11 of SiO ₂ with a thickness of 0.5 μm is formed on the substrate 10 by thermal oxidation at 1000 ° C. Next, a thermally resistive SiC layer 0.8 μm thick (not shown in FIG. 5) is applied to the sublayer 11 by sputtering the polycrystalline SiC target with a magnetron in argon at a substrate temperature of 850 ° C, in which SiC thermistors 12 and 13 are formed for TEC 1 and 2, respectively, microprofiling using plasma chemical etching. Next, metallized contact pads 14 and their electrical connections with thermistors 12 and 13 are formed by magnetron deposition of Ni followed by photolithography.

Then on the free side of the substrate 10 at the location of the thermistor 12, a blind hole 23 is etched to reduce the inertia of the TCE 1 and glued to the base 15 with this side.

Next, the information chip is connected to an external measuring circuit, made according to figure 2 with a value of the coefficient k (see formula 2) equal to 1.0. The chip is tested as in example 1.

The test results are shown in table.2. As can be seen from the table, in the steady state, the temperature T _{2 is} less than T ₁ by 1-3 ° C, which indicates the presence in this design variant of the temperature difference between the medium and the housing in the static. In the dynamic mode, the maximum value of X _O on 5-9 ° C above the temperature established at the end of the transient caused by an abrupt increase in the setpoint temperature controller. There is also a pre-emptive output signal X _o , which can be used to timely suppress the emergency state of the object.

As explained by the above examples, the use of the proposed technical solutions increases the information content of the vehicle due to the possibility of measuring the temperature of the medium and the wall of the room (apparatus) in statics and a pronounced anticipatory signal that takes into account the rate of change of temperature conditions in dynamics, which also indicates an increase in the sensitivity of the vehicle. A positive result, derived from the achieved, lies in the possibility of using the output signal, adjusted for the rate of change of temperature conditions, to form the differential component of the corresponding automatic control system for the controlled process. The possibility of miniaturization of the node of the information microcircuit due to its manufacture using the described microtechnology was also achieved.

Table 1
Test results of a vehicle with an information chip for example 1 Initial temperature, ° С The steady-state temperature at the end of the transition process, ° C The maximum value of X _o in the transition process, ° C adjustable in the environment T ₁ T ₂ twenty 20 ± 1 19 ± 1 fifty 66 35 35 ± 1 33.5 ± 1 65 74 fifty 50 ± 0.5 49 ± 0.5 80 92 100 97 ± 1 95 ± 1 130 140 150 147 ± 2 144 ± 2 180 190 250 246 ± 2 242 ± 2 280 292 table 2
Test results of a vehicle with an information chip for example 2 Initial temperature, ° С The steady-state temperature at the end of the transition process, ° C The maximum value of X _o in the transition process, ° C adjustable in the environment T ₁ T ₂ twenty 20 ± 1 19 ± 1 fifty 56 35 35 ± 1 34 ± 1 65 70 fifty 50 ± 1 49 ± 1 80 88 100 97 ± 2 95 ± 2 130 139 150 147 ± 2 145 ± 2 180 188 250 246 ± 3 243 ± 2 280 286

Claims (3)

1. A temperature measuring system comprising an information microcircuit and an external measuring circuit in which the information microcircuit includes a base attached to the base with low inertia and inertia thermosensitive elements based on thermistors mounted on a solid substrate with the ability to measure the temperature of the medium and the walls of the controlled room, respectively, and electrical leads for connecting thermosensitive elements to an external measuring circuit, and the external measuring circuit is equipped with a comparison unit and an indication unit, wherein the low-inertia thermosensitive element is connected to the first input of the comparison unit, and the inertial heat-sensitive element is connected to the second input of the comparison unit, characterized in that a semiconductor material is used as a substrate for the thermistors, an adder and a first are additionally installed in the external measuring circuit and the second amplifier-converters, a low-inertia thermosensitive element is connected to the first input of the comparison unit and to the first input of the sum the matora through the first amplifier-converter, the inertial thermosensitive element is connected to the second input of the comparison unit through the second amplifier-converter, the output of the comparison unit is connected to the second input of the adder, the output of the adder is connected to the input of the display unit directly or through a switch. 2. The temperature measuring system according to claim 1, characterized in that the display unit is made of three channels, wherein the adder output is connected to the first input of the display unit, the output of the first amplifier-converter is additionally connected to the second input of the display unit, and the output of the second amplifier-converter is additionally connected to the third input of the display unit. 3. A method of manufacturing an information chip for a temperature measuring system, comprising forming thermistors of low inertia and inertia thermosensitive elements on a substrate made of a solid body, attaching thermosensitive elements to the base of the microcircuit, and attaching thermosensitive elements to electrical terminals for connecting to an external measuring circuit, characterized in that thermistors are formed by applying a thermoresistive layer to a semiconductor substrate material, followed by microprofiling of this layer, making metallized contact pads and connecting them to the corresponding heat-sensitive elements, while the substrate section at the location of the thermistor of the low-inertia heat-sensitive element is removed or etched in it a blind hole, then the heat-sensitive elements are attached to the base and the contact pads are connected to electrical conclusions mounted in the base of the chip.

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