CN201335993Y

CN201335993Y - Precision temperature-control system

Info

Publication number: CN201335993Y
Application number: CNU2008202109441U
Authority: CN
Inventors: 罗卫国; 罗亮
Original assignee: CETC 48 Research Institute
Current assignee: CETC 48 Research Institute
Priority date: 2008-12-15
Filing date: 2008-12-15
Publication date: 2009-10-28
Anticipated expiration: 2018-12-15

Abstract

The utility model discloses a precision temperature-control system comprising an external-heating couple arranged on the outer wall of a furnace cavity, and an internal-heating couple arranged in a reaction tube. The precision temperature-control system further comprises a double-input loop temperature controller consisting of a main regulator and an auxiliary regulator in parallel connection. After the internal-heating couple of the precision temperature-control system is connected with a detection input terminal at the front of the main regulator in the double-input loop temperature controller through compensation conducting wires, and the external-heating couple is connected with the main adjuster in the double-input loop temperature controller, the detection input terminal at the front of the auxiliary adjuster and the control output terminal of the double-input loop temperature controller are connected to a controllable silicon trigger and accessed into a heating module through a controllable silicon and a transformer connected with the controllable silicon in parallel, wherein the double-input loop controller is connected with an industrial control computer. The precision temperature-control system of the utility model has the advantages that the temperature-controlling performance is good, the responding speed is high, the actual temperature of the position where a technical device is located can be reflected really, and the ideal effect can be achieved for thermal objects with the strict requirements on the large volume of the furnace cavity, the system fluctuation and the temperature.

Description

A kind of precision temperature control system

Technical field

The utility model belongs to the electrical heating domain of control temperature, specifically is a kind of temperature control system that is used for semicon industry electric heating equipments such as microelectronics, photoelectron, power electronics.

Background technology

With regard to the heating target of pipe in the general band furnace chamber (for example quartz ampoule, SiC pipe etc.), owing to the obstruction of pipe in being subjected to and to requirement not strict especially on the control accuracy, thereby the temperature control mode that generally adopts is one or many thermopairs to be set as the temperature detection to controlled device in the furnace chamber outer wall, temperature controller with detected value and desired temperature relatively after, the heating power of adjusting boiler tube by the power control loop joint is controlled the technology sheet temperature in the reaction tube.This kind temperature control technology is simple, practical, and cost is lower, can satisfy the needs of general heating system.

If but the temperature control precision of controlled device is strict, and controll plant produces bigger fluctuation because of the meeting that influences of air-flow, environment, line voltage thereupon, and then this temperature control method just is difficult to satisfy this requirement.Temperature control method with conventional diffusion furnace is an example, because inboard wall of burner hearth separating process sheet is (generally more than 50mm) far away, add the obstruct of the relatively poor and reaction tube wall of the thermal conductivity of gas, the thermocouple induction that variation of temperature will be placed on the furnace wall in the crystal reaction tube arrives the one long period that needs, in the technological process, variation along with gas flow, temperature in the reaction tube can change thereupon, and with respect to this variation, the action of humidity control system has bigger hysteresis quality, thereby causes the fluctuation of temperature in the reaction tube.

Obviously, the system that the flat-temperature zone frequently is disturbed as requirements such as liquid phase epitaxy stove, this stability to temperature of high-accuracy diffusion furnace, temperature variation response speed, temperature dynamic range of adjustment are all very high, if also adopt this thermopair to come temperature control away from the mode of controlled point, will inevitably make stabilization time of controlled device temperature drag very longly and can fluctuation status occur thereupon, thereby be difficult to satisfy the requirement of high-precision temperature index because of variations such as process gas flow, environment temperature, supply voltages.

Want in controlled temperature variation, in time to detect and react rapidly, near final controlled device (technology sheet), just must have thermopair to participate in temperature control.

The utility model content

In order to overcome the deficiency that conventional temperature control equipment could not detect and control technology sheet true temperature in the reaction tube in real time, the utility model provides a kind of temperature control performance good, the temperature control equipment that response speed is fast.Its temperature-controlled precision height, response speed are fast and can truly reflect the actual temperature of technology device present position, big for the furnace chamber volume, system fluctuation big, to the thermal object of temperature requirement strictness, can obtain desirable effect.

The technical scheme that its technical matters that solves the utility model adopts is: a kind of precision temperature control system, comprise outer thermopair that is positioned at the furnace chamber outer wall and the thermopair that is positioned at reaction tube, it is characterized in that, also comprise a dual input loop temperature controller that is composed in series by master selector and secondary controller, wherein interior thermopair is connected to the detection input end before the master selector in the temperature controller of dual input loop by compensating wire, outer thermopair then is connected in the temperature controller of dual input loop behind the master selector by compensating wire, detection input end before the secondary controller, the control output end of dual input loop temperature controller is connected to silicon controlled toggle, and the transformer by controllable silicon and series connection with it inserts heating module, and wherein dual input loop temperature controller is connected with industrial control computer.

As preferred version, described interior thermopair is positioned at the little quartz ampoule of reaction tube afterbody, the inner sealing of described little quartz ampoule, and openend extends to outside the reaction tube, and it is welded on the reaction tube madial wall along the reaction tube parallel direction.

As preferred version, described interior thermoelectric on a rare occasion end is connected on the SiC oar seat of push-and-pull technology sheet, is positioned at the reaction tube front portion.

Above-mentioned dual input loop temperature controller is a SDC40B dual input loop temperature controller.

Principle of work of the present utility model is, on the basis of traditional reaction tube outer wall temperature control, increases a cover thermopair again newly in reaction tube inside, simultaneously, traditional single input circuit temperature controller changed into adopt dual input loop temperature controller; The temperature signal that inside and outside thermopair is gathered amplifies the output that the back forms tandem pattern control body of heater power heating module by the temperature controller computing of dual input loop, thereby reaches the purpose of precise temperature control.

According to the purposes difference of equipment, the mode of thermopair in can taking respectively to be provided with from reaction tube afterbody or reaction tube front portion.Thermopair is fairly simple in wherein being provided with from the afterbody of reaction tube, is example with the crystal reaction tube, only needs add inner little quartz ampoule that seals of weldering, as close as possible technology sheet position, its position at the madial wall of crystal reaction tube with the pipe parallel direction.The openend of little quartz ampoule extends to outside the crystal reaction tube, like this, interior thermopair put into little quartz ampoule after, can closely detect near the true temperature the technology sheet.The mode of thermopair then wants complicated a lot of relatively in being provided with from fire door, and the sealing of thermopair and fire door and interior thermopair can pass in and out reaction tube with push-and-pull technology sheet device and move in considering.The utility model is by adopting metallic bellows and quartzy oven door sealing, interior thermopair then passes metallic bellows and quartzy fire door enters reaction tube inside, thereby reach purpose with external isolation, simultaneously, metallic bellows, quartzy fire door, interior thermoelectricity are on a rare occasion held on the SiC oar seat that is fixed on push-and-pull technology sheet, like this, interior thermopair can moving horizontally and pass in and out reaction tube with SiC oar seat.

The described interior thermopair that is placed in the reaction tube is connected to a detection input end of two-circuit temperature controller by compensating wire, outer thermopair then is connected to another detection input end of dual input loop temperature controller by compensating wire, the control output of dual input loop temperature controller is connected to silicon controlled toggle.The desired temperature of dual input loop temperature controller then by with industrial control computer communication cause technology working procedure automatic setting.

In heating process, one group of PID regulating system of the outer thermopair that places furnace wall place and dual input loop temperature controller and silicon controlled toggle, heating module encircle secondary regulating loop in forming, and are used for controlling the size of stove silk heating current; And the position is corresponding with outer thermopair, be put near the interior thermopair the technology sheet in the reaction tube then with the temperature mV value that records and setting value relatively after, form outer shroud main regulation loop with PID1, the PID2 of temperature controller and trigger, heating module, monitor the temperature variation of flat-temperature zone in the reaction tube.Like this, when extraneous interference such as line voltage, variation of ambient temperature occurring, outer thermopair detects at first, and by adjusting link it is proofreaied and correct before furnace temperature is impacted; And in the reaction tube because the moving of boat, variations in flow, vacuum tightness variation etc. when causing temperature variation, interior thermopair can detect immediately and draw, and regulates power rapidly and export and overcome disturbance to Temperature Influence after temperature controller comparison, computing.

Precision temperature control system described in the utility model, temperature control performance is good, and response speed is fast, and can truly reflect the actual temperature of technology device present position,, system fluctuation big for the furnace chamber volume be big, to the thermal object of temperature requirement strictness, can obtain desirable effect.

Below in conjunction with drawings and Examples the utility model is further specified.

Description of drawings

Fig. 1 is the structural representation of the described precision temperature control device of embodiment;

The outer thermopair 3-reaction tube 4-furnace chamber outer wall of thermopair 2-in the 1-

5-dual input loop temperature controller 6-silicon controlled toggle 7-controllable silicon

8-transformer 9-temperature master selector 10-temperature secondary controller

The 11-compensating wire

Embodiment

Described precision temperature control device is a kind of tandem temperature control system, and it has following characteristics: 1, the temperature regulator in major and minor two loops is tandem workings, and the control output quantity of temperature master selector promptly is the desired temperature of subloop temperature secondary controller.2, on regulatory function, the outer shroud major loop is finished is adjusting to the technological temperature setting value, and interior ring subloop then is the adjusting to outer shroud major loop output variable.3, final output controlled quentity controlled variable places interior ring subloop control system, therefore, before much arriving the technology sheet from the disturbing effect outside the process duct, can all or most of be overcome rapidly by subloop.The outer shroud major loop comprises interior thermopair 1, compensating wire 11, temperature master selector 9, temperature secondary controller 10, silicon controlled toggle 6, controllable silicon 7, transformer 8, heating furnace body, the technology sheet reaction chamber that connects successively; Interior ring subloop then is made up of the outer thermopair 2, compensating wire 11, temperature secondary controller 10, silicon controlled toggle 6, controllable silicon 7, transformer 8, the heating furnace body that connect successively.Described outer thermopair 2 is positioned at furnace chamber outer wall 4, thermopair 1 is positioned at reaction tube 3 in described, wherein interior thermopair 1 is connected to the detection input end before the temperature master selector 9 in the dual input loop temperature controller 5 by compensating

wire

11,2 of outer thermopairs are connected in the dual input loop temperature controller 5 behind the temperature master selector 9 by compensating wire 11, detection input end before the temperature secondary controller 10, the control output end of dual input loop temperature controller 5 is connected to silicon controlled toggle 6, and insert heating modules by the transformer 8 of controllable silicon 7 and series connection with it, wherein dual input loop temperature controller is connected with industrial control computer.

In the described liquid phase epitaxy of present embodiment system, adopted temperature master selector 9, temperature secondary controller 10 are combined in the high-grade SDC40B dual input of the import in an instrument loop temperature controller.

When causing that furnace temperature is lower than setting value for a certain reason, as can be seen from Figure 1, following variation will be arranged: interior furnace temperature reduces, after interior thermopair 1 detects, the input end that feeds back to dual input loop temperature controller 5 is compared with the setting value of its inner setting, what at this moment temperature master selector 9 was felt is a minus deviation, and the output after relatively reaching the PID1 computing will increase, and this that is to say that the setting value to the temperature secondary controller 10 in the interior ring subloop increases.

And meanwhile, because outer furnace temperature reduces, detect and feed back to the input end of dual input loop temperature controller 5 through outer thermopair 2, with the output valve of above-mentioned PID1 relatively after, what temperature secondary controller 10 was felt is a bigger minus deviation, again after the PID2 computing, export a bigger value, by silicon controlled toggle 6 conduction angle of controllable silicon 7 is increased rapidly, the hurried increase of stove silk heating current, thus make furnace temperature return to setting value very soon.Same reason owing to voltage reduces when furnace temperature is changed, by the regulating action of interior ring subloop, only needs change slightly output, can this variable effect make before the temperature in the reaction tube system rapidly recovery stablize.

Obviously, for from the interference outside the controlled system, lack because interior ring subloop is regulated passage, time constant is little, thereby response speed is fast, and regulating action just at the right time; And for from the interference of reaction tube inside (as in the technological process along with the change of throughput, cause that near the thermal field the technology sheet changes), after 9 computings of temperature master selector, its output valve---just the setting value of temperature secondary controller 10 changes, the setting value of the detected value of outer thermopair 2 and temperature secondary controller 10 just has a bigger deviation after relatively, thereby also can regulate output quantity rapidly, thereby to play the effect of quickening inhibition from the interference of reaction tube 3 inside.

As known from the above, interior ring subloop has first accent, coarse adjustment, fast characteristics of transferring, and the outer shroud major loop then has back accent, fine tuning, the characteristics of accent slowly, and can internally encircle the interference that subloop do not eliminate and thoroughly overcome.

This control system is owing to adopt major and minor loop tandem to regulate, improved the response characteristic of controlled device, adjustment process is accelerated, shown the interference of ring subloop in can not only overcoming rapidly to fall to act on, and can play the good restraining effect equally the interference that acts on the master control object.By cooperatively interacting of major and minor loop in the tandem humidity control system, give full play to complementary regulating action, improved the reaction velocity of system effectively to temperature variation, overcome the control lag phenomenon, improved the temperature control precision of controlled device.

Claims

1, a kind of precision temperature control system, comprise outer thermopair that is positioned at the furnace chamber outer wall and the thermopair that is positioned at reaction tube, it is characterized in that, also comprise a dual input loop temperature controller that is composed in series by master selector and secondary controller, wherein interior thermopair is connected to the detection input end before the master selector in the temperature controller of dual input loop by compensating wire, outer thermopair then is connected in the temperature controller of dual input loop behind the master selector by compensating wire, detection input end before the secondary controller, the control output end of dual input loop temperature controller is connected to silicon controlled toggle, and the transformer by controllable silicon and series connection with it inserts heating module, and wherein dual input loop temperature controller is connected with industrial control computer.

2, according to the described precision temperature control system of claim 1, it is characterized in that described interior thermopair is positioned at the little quartz ampoule of reaction tube afterbody, the inner sealing of described little quartz ampoule, openend extends to outside the reaction tube, and it is welded on the reaction tube madial wall along the reaction tube parallel direction.

According to the described precision temperature control system of claim 1, it is characterized in that 3, described interior thermoelectric on a rare occasion end is connected the SiC oar seat that is used for push-and-pull technology sheet, it is positioned at the reaction tube front portion.

According to the described precision temperature control system of one of claim 1-3, it is characterized in that 4, above-mentioned dual input loop temperature controller is a SDC40B dual input loop temperature controller.