CN105990188A - Heating device used for semiconductor fast annealing and control method - Google Patents

Abstract

A heating device and control method for rapid annealing of semiconductors, including a power supply module, a rectification and filtering module, an IGBT module, a PWM signal drive module, a heating lamp group, and a computer control system; the power supply module is connected to the rectification and filtering module ; Wherein, the IGBT module includes an input port, a control port and an output port, the rectification and filtering module is connected to the input port of the IGBT module, the PWM signal drive module is connected to the IGBT control port, and the PWM signal drive module is controlled by the computer control system to control the conduction of the IGBT and off time to adjust the heating power of the heating lamp; the heating lamp group is connected to the IGBT output port for device heating. The invention provides a heating device and control method for rapid annealing of semiconductors, which can effectively suppress the overshoot phenomenon that occurs during the rapid temperature rise process, realize stable temperature rise, and avoid heating instability caused by stroboscopic flicker at the same time, To achieve the purpose of prolonging the service life of the lamp tube.

Description

A heating device and control method for rapid annealing of semiconductors

technical field

The invention relates to the field of semiconductor manufacturing and processing, in particular to a semiconductor heat treatment process device and a heating control method.

Background technique

At present, the heat treatment equipment of the traditional rapid annealing process adjusts the conduction angle of the thyristor to adjust the radiation power of the lamp tube to achieve the effect of rapid temperature rise. However, due to the limitation of the dead zone of the thyristor regulation, and in order to avoid the excessively fast temperature rise rate during the heating process, the method of strobe flickering of the radiation lamp is generally used to achieve a stable temperature rise rate and a constant annealing temperature in the rapid annealing process. Therefore, The inconvenience is that during the heat treatment process of the rapid annealing process, the strobe cycle of the heating lamp regulated by the thyristor is long, which seriously affects the stability of the temperature during the heating process. At the same time, the frequent switching of the heating lamp also affects the heating lamp. tube life. In addition, in the control method of driving the thyristor to adjust the lamp tube, the PID algorithm (closed-loop control algorithm) is usually used to achieve the purpose of the thyristor to adjust the lamp tube heating. This control method will inevitably introduce temperature overshoot, and the same Affects the temperature stability of the annealing process.

Contents of the invention

The technical problem to be solved by the present invention is to provide a heating device and control method for rapid annealing of semiconductors, by using an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) to directly drive the lamp tube to work, combined with pulse width The modulation (Pulse Width Modulation, PWM) signal drives the IGBT to work, so that the heating lamp is in an approximately continuous working state, achieving the beneficial effects of suppressing overshoot and prolonging the service life of the heating lamp.

In order to achieve the above invention and creation purpose, the present invention adopts the following technical solutions:

A heating device for rapid annealing of semiconductors, including a power supply module, a rectification and filtering module, an IGBT module, a PWM signal drive module, a computer control system, and several heating lamp tube groups; the power supply module is connected to the rectification and filtering module; the The IGBT module includes an input port, a drive signal control port and an output port corresponding to the IGBT input port, the rectification and filtering module is connected to the IGBT input port, and the rectification and filtering module outputs direct current to supply power to the IGBT module; The computer control system is used to control the duty cycle value of the PWM signal by controlling the PWM signal driving module; the PWM signal driving module is connected to the driving signal control port for outputting the PWM signal to control the on and off time of the IGBT module, and then adjust The heating lamp group radiates power; the heating lamp group is connected to the output port corresponding to the IGBT input port for heating.

Further, it also includes a computer system connected to the PWM signal driving module for controlling and adjusting the duty cycle of the PWM signal; the frequency of the PWM signal is between 1kHz and 30kHz

Further, the number of output ports corresponding to the IGBT input port is 3, the number of the heating lamp groups is 3 groups, and each of the output ports is respectively connected to one of the heating lamp groups.

Further, the heating lamp group is composed of several halogen tungsten lamps.

The present invention also provides a control method for a semiconductor rapid annealing heating device, comprising the following steps:

Step 1: Connect a power supply module, a rectification and filtering module, an IGBT module and several heating lamp tube groups in sequence; the power supply module outputs direct current through the rectification and filtering module to supply power for the IGBT module; a PWM signal driving module is respectively connected to a The computer control system and the connection of the IGBT module;

Step 2: Input the heating rate x, the equilibrium temperature z of the heating device and the required heating rate _x0 when reaching a switching point temperature T in the computer control system with a preset heating curve;

The computer control system controls the PWM signal driving module to output the first PWM signal duty ratio D1 to the IGBT module according to the heating rate x, and the heating lamp group is in a heating mode through the IGBT module; wherein , the relationship between the duty cycle D1 of the first PWM signal and the heating rate x is obtained by formula 1:

$\mathrm{D.}1=\left\{\begin{array}{cc}(x-3.629)/0.9& 0<x\&le;300\\ (x-1.716)/0.927& 300<x\&le;350\\ (x-0.434)/0.945& 350<x\&le;400\\ (x+2.193)/0.98& 400<x\&le;450\\ (x+6.042)/1.03& 450<x\&le;500\\ (x+11.277)/1.099& 500<x\&le;550\\ (x+13.526)/1.1121& 550<x<600\end{array}\right.$ Formula 1

Among them, the unit of x is ℃/s, and D1 is a dimensionless value;

Wherein, the computer control system queries the switching temperature T corresponding to the equilibrium temperature z at the heating rate x according to formula 2;

$T=\left\{\begin{array}{cc}\frac{z}{100}x-5x-1.3z+460& 200\&le;x\&le;300\\ -4x+1.3z+720& 300<x\&le;400\\ -4x-1.75z+1160& 400<x\&le;500\\ -4x-1.35z+1310& 500<x\&le;600\end{array}\right.$ Formula 2

Among them, the unit of T is °C, and the unit of z is °C;

Step 3: When the current temperature of the heating lamp group is the same as the switching temperature T, the computer control system controls the PWM signal driving module to output a second PWM signal duty ratio D2, so that the IGBT module drives the The heating lamp group is in the heat preservation mode, so that the temperature of the heating device gradually rises from the switching point to the equilibrium temperature and then becomes constant, wherein the duty cycle D2 of the second PWM signal is obtained by formula 3:

$\mathrm{D.}2=7.68926+\frac{411.01498}{1+{10}^{(3954.39853-x_0)*6.27941\mathrm{E.}-4)}}$ Formula 3;

Wherein, D2 is a dimensionless value; and the _x0 is the switch from Celsius temperature to digital quantity, which is dimensionless and obtained by formula 4,

$x_0=\sqrt{\frac{9588.3+z}{2.621\mathrm{E.}-6}}-\frac{0.1585}{2.621\mathrm{E.}-6}$ Formula 4

Among them, z is the equilibrium temperature in °C.

Further, the duty cycle of the first PWM signal and the second PWM signal is different; the number of bits of the first PWM signal and the second PWM signal is between 10 bits and 20 bits; the first PWM signal , The frequency of the second PWM signal is between 1kHz and 30kHz.

Further, the difference between the switch point temperature and the equilibrium point temperature ranges from 5°C to 150°C.

Further, the ranges of the heating rates x and _x0 are both between 5°C and 150°C/s.

Further, the equilibrium temperature range is 200-600°C.

Beneficial effects of the present invention:

In summary, the present invention provides a heating device and control method for rapid annealing of semiconductors, using a method in which the IGBT module directly drives the lamp tube to work, combined with a PWM signal of 1 kHz to 30 kHz to drive the IGBT module to work, so that the lamp tube is in the In an approximately continuous working state, compare the difference between the current temperature and the next set balance point temperature in real time. When the real-time temperature distance from the set balance temperature reaches the switching point temperature value, switch the duty cycle value to the set balance point The duty cycle value required by the temperature can achieve stable temperature rise, effectively suppress the temperature overshoot that occurs during the rapid temperature rise process, and reduce the heating instability caused by flicker at the same time, and realize the benefits of simple structure, safety, stability and high efficiency. Effect, and to achieve the purpose of prolonging the service life of the lamp tube.

Description of drawings

FIG. 1 is a schematic diagram of a heating device for rapid annealing of a semiconductor according to an embodiment of the present invention.

detailed description

In order to better illustrate the technical characteristics and structure of the present invention, the following is a detailed description in conjunction with preferred embodiments of the present invention and accompanying drawings.

Referring to FIG. 1, a heating device for rapid annealing of semiconductors includes a power supply module 10, a rectification and filtering module 20, an IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) module 40, and a PWM (pulse width modulation) signal drive The heating lamp group 50 composed of the module 30 and several lamps includes a computer system 60 connected with the PWM signal driving module 30 for controlling and adjusting the duty cycle of the PWM signal. The power supply module 10 is connected with a rectification and filtering module 20 for providing a stable DC power supply for the heating device of this embodiment. The IGBT module 40 includes an input port 41, a control port 42, and an output port 43 corresponding to the input port 41; the rectification and filtering module 20 is connected to the input port 41, and is used to output stable direct current to supply power to the IGBT module 40; PWM signal drive The module 30 is connected to the control port 42 for outputting PWM signals to control the on and off time of the IGBT module 40, thereby adjusting the radiation power of the heating lamp group 50; the heating lamp group 50 is connected to the IGBT module output port 43 for heating.

It should be noted that the IGBT module 40 is a composite fully-controlled voltage-driven power semiconductor device composed of a bipolar transistor and an insulated gate field effect transistor, specifically a 1800A high-current IGBT module with high input impedance and low conductance. characteristics of pressure drop. During the working process, the beneficial effects of small driving power, fast switching speed, reduced conduction voltage and high current-carrying density are produced.

Specifically, in this embodiment, the operating frequency of the PWM signal is selected to be 10 kHz, and the PWM signal driving module 30 outputs a 10 kHz PWM signal to control the operation of the IGBT module 40 . The power module 10 outputs three-phase alternating current, which is converted into direct current by the rectifying and filtering module 20 and then connected to the input port 41 of the IGBT module 40 . Among them, there are three groups of heating lamp groups 50, and each group includes 9 tungsten-halogen lamps. Every three lamps are connected in series and then in parallel. The equivalent resistance is the resistance of one tungsten-halogen lamp. The number of output ports 43 is 3, and each output port 43 is respectively connected to a heating lamp group 50 (ie, 9 lamp tubes). The tungsten-halogen lamp tube used is the radiation heating of the heating device, and the single power is 1500W. It should be noted that the resistance of the tungsten-halogen lamp is larger than that at room temperature, so when selecting the maximum operating current of the IGBT, it is necessary to avoid breakdown of the IGBT module when supplying power to the heating lamp, and the frequency of the PWM signal driving the IGBT should be at the maximum IGBT Within the operating frequency, the operating frequency of the tungsten-halogen lamp controlled by the IGBT is the PWM signal frequency, thus completely avoiding the stroboscopic state of the heating lamp group 50, ensuring the stability of the heating process and prolonging the service life of the lamp 50 .

Embodiments of the present invention also provide a method for controlling a heating device for rapid annealing of semiconductors, including the following steps:

Step 1: Connect a power supply module 10, a rectification and filtering module 20, an IGBT module 40, and several heating lamp tube groups 50 in sequence; the power supply module 10 outputs direct current through the rectification and filtering module 20 to supply power for the IGBT module 40; The PWM signal driving module 30 is respectively connected with a computer control system 60 and the IGBT module 40;

Step 2: When the heating process starts, the computer control system controls the PWM signal drive module to output the first PWM signal to the IGBT module according to the heating curve, and drives the IGBT module so that the heating lamp group is in the heating state. Mode, at this time the heating lamp group works normally according to the set heating rate.

Input the heating rate x, the equilibrium temperature z of the heating device and the required heating rate x ₀ when reaching a switching point temperature T into the computer control system with a preset heating curve. Wherein, the heating rate x is judged by the empirical formula (1) obtained through multiple heating process simulations, and the specific empirical formula is:

$\mathrm{D.}1=\left\{\begin{array}{cc}(x-3.629)/0.9& 0<x\&le;300\\ (x-1.716)/0.927& 300<x\&le;350\\ (x-0.434)/0.945& 350<x\&le;400\\ (x+2.193)/0.98& 400<x\&le;450\\ (x+6.042)/1.03& 450<x\&le;500\\ (x+11.277)/1.099& 500<x\&le;550\\ (x+13.526)/1.1121& 550<x<600\end{array}\right.$ (1)

Among them, x is the heating rate, the unit is ℃/s, and the manual input range is generally 5 to 150 ℃/s; D1 is the duty cycle value of the PWM signal, and the frequency is between 1 and 30kHz.

Once the equilibrium temperature and heating rate are set, the computer control system can find the switching point temperature T corresponding to the set equilibrium temperature z under the current heating rate x from the heating curve, and the formula corresponding to the switching point temperature:

$T=\left\{\begin{array}{cc}\frac{z}{100}x-5x-1.3z+460& 200\&le;x\&le;300\\ -4x+1.3z+720& 300<x\&le;400\\ -4x-1.75z+1160& 400<x\&le;500\\ -4x-1.35z+1310& 500<x\&le;600\end{array}\right.$ Formula (2)

Where x is the heating rate, in ℃/s, and the manual input range is generally 5 to 150 ℃/s; z is the equilibrium point temperature, in ℃; T is the switching point temperature, in ℃.

Step 3: After a period of time, when there is a difference between the current temperature of the heating lamp group and the equilibrium temperature, which is in the range of 5-150°C, and the current temperature has reached the switching temperature T, the computer control system The PWM signal driving module is controlled to switch the duty ratio of the PWM signal from D1 to D2, and the temperature rise rate of the heating lamp group is changed to x ₀ , so that the IGBT module drives the heating lamp group to keep warm.

The appropriate PWM signal duty cycle value D2 corresponding to the equilibrium temperature is obtained by the following formula (3):

$\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 7.68926</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 411.01498</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3954.39853</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; 6.27941</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Among them, x ₀ is the temperature rise rate after reaching the switching point temperature T, the unit is ℃/s, and the range is generally 5 to 150 ℃/s; x ₀ is obtained by formula (4);

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 9588.3</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; z</span>}}{\mathrm{<span\; class="notranslate">\; 2.621</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6</span>}}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 0.1585</span>}}{\mathrm{<span\; class="notranslate">\; 2.621</span>}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Among them, z is the temperature value of the equilibrium point, in °C; the value range of z is between 200 °C and 600 °C, that is, it is input by user definition.

Wherein, the duty cycle of the second PWM signal is different from the duty cycle of the first PWM signal, the duty cycle value of the first PWM signal is obtained by formula (1), and the duty cycle value of the second PWM signal is obtained by the formula ( 3) (4) obtained, through the adjustment of the computer control system, the second PWM signal is sent to the IGBT module, and then controlled to change the working state, and finally achieve the control of the heating lamp group to be in the low radiation power working mode or stop the heating work, so that The temperature of the heating device gradually rises from the switching point to the equilibrium temperature and then becomes constant, so as to avoid the situation of temperature overshoot.

It can be seen that the present invention uses the basic parameters of the temperature curve to adjust the duty ratio of the PWM signal. Specifically, by predicting the equilibrium temperature, heating rate and switching point temperature of the preset temperature curve, the duty cycle value is set so that the temperature rise gradually approaches the required equilibrium temperature value, effectively suppressing the temperature overshoot. Through the pre-judgment analysis, the duty ratio of the PWM signal is adjusted in real time during the heating process to control the radiant power of the lamp tube to ensure a stable heating rate. In the process of heating up to a constant temperature, switch the PWM signal duty cycle value in advance, and the switching time and switching duty cycle value need to be obtained by formula (2), which can suppress the temperature overshoot.

Specifically, the number of bits of the PWM signal in the present invention is between 10 bits and 20 bits. In this embodiment, the number of bits of the first PWM signal and the second PWM signal is selected as 12 bits. The frequency of the control signal output by the IGBT is the same as the working frequency of the heating lamp group.

It should be noted that the number of bits of the PWM signal determines the control accuracy of the radiant power of the tungsten-halogen lamp, and the converted DC voltage output by the rectification and filtering module 20 determines the operating voltage of the tungsten-halogen lamp. In this implementation, a 12-bit PWM The signal adjusts the radiation power of the heating lamp group 50 to ensure a good adjustment accuracy of the duty ratio, thereby effectively improving the control accuracy of the radiation power of the tungsten-halogen lamp.

In summary, the present invention provides a heating device and control method for rapid annealing of semiconductors, using a method in which the IGBT module directly drives the lamp tube to work, combined with a PWM signal of 1 kHz to 30 kHz to drive the IGBT module to work, so that the lamp tube is in the In the continuous working state, the duty cycle is set by the pre-judgment analysis method to achieve a stable temperature rise, which effectively suppresses the overshoot phenomenon that occurs during the rapid temperature rise process, and at the same time reduces the heating instability caused by the strobe, and realizes the structure Simple, safe, stable and efficient beneficial effects, and achieve the purpose of prolonging the service life of the lamp tube.

The above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (9)

1. a heating device for semiconductor rapid annealing, is characterized in that, comprises power supply module (10), rectifier filter module (20), IGBT module (40), PWM signal driving module (30), computer control system (60) ) and heating lamp tube group (50); the power supply module (10) is connected to the rectification filter module (20); the IGBT module (40) includes an input port (41), a drive signal control port (42) and The output port (43) corresponding to the IGBT input port, the rectification and filtering module (20) is connected to the IGBT input port (41), and the rectification and filtering module (20) outputs direct current to supply power for the IGBT module (40); The computer control system (60) controls the PWM signal duty cycle value through the PWM signal driving module (30); the PWM signal driving module (30) is connected to the driving signal control port (42) for outputting the PWM signal to control the The IGBT module (40) is turned on and off, and then the radiation power of the heating lamp group (50) is adjusted; the heating lamp group (50) is connected to the output port (43) corresponding to the IGBT input port, For fever. 2 . The heating device for rapid annealing of semiconductors according to claim 1 , wherein the frequency of the PWM signal is between 1 kHz and 30 kHz. 3. The heating device for semiconductor rapid annealing according to claim 1, characterized in that, the number of output ports (43) corresponding to the IGBT input port is 3, and the number of the heating lamp tube group (50) The quantity is 3 groups, and each of the output ports (43) is respectively connected with one of the heating lamp tube groups (50). 4. The heating device for rapid annealing of semiconductors according to claim 3, characterized in that, the heating lamp group (50) is composed of several halogen tungsten lamps. 5. A control method for a semiconductor rapid annealing heating device, characterized in that, comprising the following steps: Step 1: Connect a power supply module, a rectification and filtering module, an IGBT module and several heating lamp tube groups in sequence; the power supply module outputs direct current through the rectification and filtering module to supply power for the IGBT module; a PWM signal driving module is respectively connected to a The computer control system and the connection of the IGBT module; Step 2: Input the heating rate x and the equilibrium temperature z into the computer control system to obtain the heating curve information; The computer control system controls the PWM signal driving module to output the first PWM signal duty ratio D1 to the IGBT module according to the heating rate x, and the heating lamp group is in a heating mode through the IGBT module; wherein , the relationship between the duty cycle D1 of the first PWM signal and the heating rate x is obtained by formula 1: $\mathrm{D.}1=\left\{\begin{array}{cc}(x-3.629)/0.9& 0<x\&le;300\\ (x-1.716)/0.927& 300<x\&le;350\\ (x-0.434)/0.945& 350<x\&le;400\\ (x+2.193)/0.98& 400<x\&le;450\\ (x+6.042)/1.03& 450<x\&le;500\\ (x+11.277)/1.099& 500<x\&le;550\\ (x+13.526)/1.112& 550<x<600\end{array}\right.$ Formula 1 Among them, the unit of x is ℃/s, and D1 is a dimensionless value; Wherein, the computer control system queries the switching temperature T corresponding to the equilibrium temperature z at the heating rate x according to formula 2; $T=\left\{\begin{array}{cc}\frac{z}{100}x-5x-1.3z+460& 200\&le;x\&le;300\\ -4x-1.3z+720& 300<x\&le;400\\ -4x-1.75z+1160& 400<x\&le;500\\ -4x-1.35z+1310& 500<x\&le;600\end{array}\right.$ Formula 2 Among them, the unit of T is °C, and the unit of z is °C; Step 3: When the current temperature of the heating lamp group is the same as the switching temperature T, the computer control system controls the PWM signal driving module to output a second PWM signal duty ratio D2, so that the IGBT module drives the The heating lamp group is in the heat preservation mode, so that the temperature of the heating device gradually rises from the switching point to the equilibrium temperature and then becomes constant, wherein the duty cycle D2 of the second PWM signal is obtained by formula 3: $\mathrm{D.}2=7.68926+\frac{411.01498}{1+{10}^{(3954.39853-x_0)*6.27941\mathrm{E.}-4)}}$ Formula 3; Wherein, D2 is a dimensionless value; and the _x0 is the switch from Celsius temperature to digital quantity, which is dimensionless and obtained by formula 4, $x_0=\sqrt{\frac{9588.3+z}{2.621\mathrm{E.}-6}}-\frac{0.1585}{2.621\mathrm{E.}-6}$ Formula 4 Among them, z is the equilibrium temperature in °C. 6. The control method according to claim 5, wherein the duty ratios of the first PWM signal and the second PWM signal are different; the digits of the first PWM signal and the second PWM signal are both 10 bit to 20 bits; the frequencies of the first PWM signal and the second PWM signal are both between 1kHz and 30kHz. 7 . The control method according to claim 5 , wherein the difference between the temperature at the switching point and the temperature at the equilibrium point is in the range of 5° C. to 150° C. 7 . 8. The control method according to claim 5, characterized in that the ranges of the heating rates x and _x0 are both between 5 and 150°C/s. 9. The control method according to claim 5, characterized in that, the equilibrium temperature range is 200-600°C.