CN114501765A - Gas dissociation circuit and gas dissociation system based on multi-coil coupling - Google Patents

Abstract

The invention provides a gas dissociation circuit based on multi-coil coupling, comprising at least two dissociation transformers and at least two reactances, the dissociation transformers include a first main coil, a first secondary coil and a reactance, the first A main coil is connected in series, the first auxiliary coil and the reactance are arranged in a one-to-one correspondence, and the first auxiliary coil is connected in series with the reactance, the turns ratio of all the dissociating transformers are the same, and the The turns ratio is the ratio of the number of turns of the first main coil and the number of turns of the first auxiliary coil in the same dissociating transformer, and the first main coils are connected in series, so that all the first main coils are connected in series. The magnitudes of the currents in the coils are the same, and the turns ratio of all the dissociating transformers are the same, so that the magnitudes of the currents in all the first sub-coils are equal, so that the magnetic field strengths generated by the reactances are the same, thereby improving the gas ionization rate. The present invention also provides a gas dissociation system.

Description

Gas dissociation circuit and gas dissociation system based on multi-coil coupling

technical field

The invention relates to the technical field of semiconductor manufacturing, in particular to a gas dissociation circuit and a gas dissociation system based on multi-coil coupling.

Background technique

Plasma refers to an ionized gas-like substance composed of atoms deprived of some electrons and positive and negative ions generated by ionization of atomic groups. Generally, it can be generated by capacitive coupling or radio frequency inductive coupling. Wide range of applications.

Plasma-assisted material processing is widely used in many industrial plants. In the semiconductor and optoelectronics industries, plasmas are used in a variety of processes, such as plasma-enhanced chemical vapor deposition, physical vapor deposition, reactive ion etching, and plasma immersion ion implantation. In addition, low pressure plasma can be used for chamber cleaning and flat panel display manufacturing. Surface treatment technology can be used for sterilization of biomedical devices. In particular, for atmospheric pressure plasmas (such as ozone), it can be applied to many types of cleaning, such as agriculture, food disinfection, water purification, and portable air filters. In order to increase the productivity of chemical vapor deposition processes, preventing contamination of the chamber is a major concern.

At present, the plasma sources at home and abroad are mainly radio frequency inductively coupled plasma sources (ICP). It has been widely used in the field, such as the etching of polysilicon, silicon dioxide and metal materials, and the preparation of metal oxide films. Existing plasma sources excite the ionization of ignition gas (such as nitrogen) through an ignition circuit, generate a magnetic field through radio frequency inductive coupling, ionize clean gases such as (NF3) and maintain a stable plasma to generate a certain density of fluoride ions for use. For cleaning the chip process chamber. However, in the prior art, the strength of the dissociation magnetic field is not uniform, and the dissociation rate is low.

Therefore, it is necessary to provide a novel gas dissociation circuit and gas dissociation system to solve the above problems in the prior art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a gas dissociation circuit and a gas dissociation system based on multi-coil coupling, which can improve the uniformity of the gas dissociation magnetic field and improve the gas dissociation rate.

In order to achieve the above objects, the gas dissociation circuit of the present invention includes at least two dissociation transformers and at least two reactances, the dissociation transformers include a first primary coil and a first secondary coil, and the first primary coil The first sub-coil and the reactance are arranged in one-to-one correspondence, and the first sub-coil and the reactance are connected in series, all the dissociation transformers have the same turns ratio, and the turns ratio is the ratio of the number of turns of the first main coil to the number of turns of the first secondary coil in the same dissociating transformer.

The beneficial effect of the gas dissociation circuit is that: the first main coils are connected in series, so that the magnitudes of the currents in all the first main coils are equal, and the turns ratio of all the dissociation transformers are the same, so that the The magnitudes of the currents in all the first sub-coils are equal, so that the magnetic field strengths generated by the reactances are the same, the uniformity of the magnetic field is improved, and the gas ionization rate is improved.

Optionally, the dissociation transformer further includes a first magnetic core, and the first main coil and the first secondary coil surround the outer side of the first magnetic core.

Optionally, the gas dissociation circuit further includes an ignition unit, the ignition unit includes an ignition transformer, the ignition transformer includes a second primary coil and a second secondary coil, the second primary coil and the first primary coil The coils are connected in series.

Optionally, the ignition transformer further includes a second magnetic core, and the second primary coil and the second secondary coil surround the outside of the second magnetic core.

Optionally, the ignition unit further includes a capacitor, and the capacitor is connected in parallel with the second main coil.

Optionally, the ignition unit further includes an ignition electrode, and the ignition electrode is connected in series with the second secondary coil.

Optionally, the ignition unit further includes a switch unit, and the switch unit is connected in parallel with the second main coil.

Optionally, the switch unit is a power switch.

Optionally, the gas dissociation circuit further includes a current source, and the current source is connected in series with the first main coil.

The present invention also provides a gas dissociation system, comprising:

a dissociation chamber; and

In the gas dissociation circuit, the reactance is arranged in the dissociation chamber.

The beneficial effect of the gas dissociation system is that: the first main coils are connected in series, so that the magnitudes of the currents in all the first main coils are equal, and the turns ratio of all the dissociation transformers are the same, so that the The magnitudes of the currents in all the first sub-coils are equal, so that the magnetic field strengths generated by the reactances are the same, the uniformity of the magnetic field is improved, and the gas ionization rate is improved.

Description of drawings

1 is a schematic structural diagram of a conventional gas dissociation system in the prior art;

Fig. 2 is the structural representation of the gas dissociation system of the present invention;

3 is a structural block diagram of an ionization rate detection device in some embodiments of the present invention;

4 is a structural block diagram of an ignition control sub-unit in some embodiments of the present invention;

FIG. 5 is a structural block diagram of a maintenance control subunit in some embodiments of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the present invention. Obviously, the described embodiments are a part of the present invention. examples, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Unless otherwise defined, technical or scientific terms used herein should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. As used herein, "comprising" and similar words mean that the elements or things appearing before the word encompass the elements or things recited after the word and their equivalents, but do not exclude other elements or things.

FIG. 1 is a schematic structural diagram of a conventional gas dissociation system in the prior art. 1 , a conventional gas dissociation system 100 includes a first transformer 101 , a second transformer 102 , a power source 103 and an ignition device 104 , and the first transformer 101 includes a first primary sub-coil 1011 and a first secondary sub-coil 1012 , the second transformer 102 includes a second main-stage sub-coil 1021 and a second sub-stage sub-coil 1022, one end of the first main-stage sub-coil 1011 and one end of the second main-stage sub-coil 1021 are both connected to the One end of the power supply 103 is connected, the other end of the first main stage sub-coil 1011 and the other end of the second main stage sub-coil 1021 are both connected to the ignition device 104, and the ignition device 104 is connected to the power supply The other end of 103 is connected.

Referring to FIG. 1 , the magnitude of the total current output by the power supply 103 is I, the magnitude of the first sub-current on the first main-stage sub-coil 1011 is I ₁ , and the magnitude of the second sub-current on the second main-stage sub-coil 1021 is I 1 . The current size is I ₂ , I=I ₁ +I ₂ . During the current adjustment process, the total current size is adjusted, but the first sub-current and the second sub-current cannot be controlled, because the The impedances of the first main-stage sub-coil 1011 and the second main-stage sub-coil 1021 are different, so the magnitude of the first sub-current and the second sub-current cannot be guaranteed to be equal, and thus the first sub-current cannot be guaranteed The current on the stage sub-coil 1012 and the current on the second sub-stage sub-coil 1022 are equal in magnitude, and the magnetic field strength generated by the first sub-stage sub-coil 1012 and the magnetic field strength generated by the second sub-stage sub-coil 1022 Different, resulting in different gas ionization rate, affecting the overall gas ionization rate.

In view of the problems existing in the prior art, embodiments of the present invention provide a gas dissociation system. Referring to FIG. 2 , the gas dissociation system 200 includes a gas dissociation circuit 201 and a dissociation chamber 202 .

In some embodiments, the gas dissociation circuit includes at least two dissociation transformers and at least two reactances.

2 , the gas dissociation circuit 201 includes two dissociation transformers 2011 and two reactances (not shown in the figure). The dissociation transformer 2011 includes a first main coil 20111 and a first secondary coil 20112, so The first main coils 20111 are connected in series, the first auxiliary coils 20112 are arranged in one-to-one correspondence with the reactances, and the first auxiliary coils 20112 are connected in series with the reactances. All the turns of the dissociation transformer 2011 The ratios are the same, and the turns ratio is the ratio of the number of turns of the first main coil 20111 to the number of turns of the first secondary coil 20112 in the same dissociating transformer 2011 . The first main coils 20111 are connected in series, and the current on the first main coil 20111 is the same. Since the turns ratio of all the dissociating transformers 2011 is the same, the current on the first secondary coil 20112 is the same. All the same, the magnetic field strengths generated by all the first sub-coils 20112 are also equal, so that the ionization rate of the gas is the same, thereby improving the ionization rate of the gas.

Referring to FIG. 2 , the dissociation transformer 2011 further includes a first magnetic core 20113 , and the first main coil 20111 and the first secondary coil 20112 surround the outer side of the first magnetic core 20113 .

2, the gas dissociation circuit 201 further includes an ignition unit 2012, the ignition unit 2012 includes an ignition transformer 20121, a capacitor 20122, a switch unit 20123 and an ignition electrode (not shown in the figure), the ignition transformer 20121 includes The second main coil 201211 and the second secondary coil 201212, the second main coil 201211 and the first main coil 20111 are connected in series, the capacitor 20122 is connected in parallel with the second main coil 201211, and the switch unit 20123 is connected to the The second main coil 201211 is connected in parallel, the ignition electrode is connected in series with the second secondary coil 201212 , and the ignition electrode is arranged in the dissociation chamber 202 .

In some embodiments, the switch unit is a power switch. Optionally, the switch unit is a metal-oxide-semiconductor field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET) or an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT).

Referring to FIG. 2 , the ignition transformer 20121 further includes a second magnetic core 201213 , and the second main coil 201211 and the second secondary coil 201212 surround the outer side of the second magnetic core 201213 .

Referring to FIG. 2 , the gas dissociation circuit 201 further includes a current source 2013 , and the current source 2013 is connected in series with the first main coil 20111 .

Referring to FIG. 2 , the gas dissociation system 200 further includes an ionization rate detection device 203 for detecting the ionization rate of the gas in the dissociation chamber 202 .

FIG. 3 is a structural block diagram of an ionization rate detection device in some embodiments of the present invention. Referring to FIG. 3 , the ionization rate detection device 203 includes a maintenance gas input control unit 2031 , an output detection unit 2032 and a calculation unit 2033 , and the maintenance gas input control unit 2031 is used to control the maintenance of the input to the dissociation chamber 202 The amount of gas, the output detection unit 2032 is used to detect the amount of the maintenance gas remaining in the output gas of the dissociation chamber 202 , and the calculation unit 2033 is used to detect the maintenance gas input to the dissociation chamber 202 according to the amount of gas The ionization rate is calculated from the amount and the amount of the sustaining gas remaining in the gas output from the dissociation chamber 202. Optionally, the maintenance gas input control unit 2031 is a flow valve, the output detection unit 2032 is a mass spectrometer, and the calculation unit 2033 is a divider.

In some embodiments, the gas dissociation system further includes an ignition gas input control unit for controlling the amount of ignition gas input into the dissociation chamber. Optionally, the ignition gas input control unit is a flow valve.

2, the gas dissociation system 200 further includes a control unit 204 for adjusting the current source 2013 according to the current in the second main coil 201211, the reference current, the ionization rate and the reference ionization rate and the switch unit 20123.

In some embodiments, the control unit includes an ignition control subunit and a maintenance control subunit,

FIG. 4 is a structural block diagram of an ignition control sub-unit in some embodiments of the present invention. 4, the ignition control sub-unit 2041 includes a first comparison unit 20411 and a first proportional-integral controller 20412, the first comparison unit 20411 is used for comparing the reference current and the current in the second main coil to obtain the first comparison result data, and the first proportional-integral controller 20412 is configured to output a switch unit control signal according to the first comparison result data, so as to control the on or off of the switch unit.

In some embodiments, the first comparison unit determines that the reference current and the current in the second main coil are equal in magnitude, and the first proportional-integral controller controls the switch unit to be turned on.

In some embodiments, the first comparison unit determines that the reference current and the current in the second main coil are not equal in magnitude, and the first proportional-integral controller controls the switch unit to turn off.

FIG. 5 is a structural block diagram of a maintenance control subunit in some embodiments of the present invention. 5, the maintenance control sub-unit 2042 includes a second comparison unit 20421, a third comparison unit 20422, a second proportional-integral controller 20423, and a third proportional-integral controller 20424, and the second comparison unit 20421 is used for comparison The magnitude of the ionization rate and the reference ionization rate is used to output the first error data. The second proportional-integral controller 20423 is used for outputting and adjusting the reference current according to the first error data. The third comparison The unit 20422 is configured to compare the adjustment reference current with the current in the second main coil to output second error data, and the third proportional-integral controller 20424 is configured to output a current source according to the second error data The control signal is used to adjust the output current of the current source.

In some embodiments, if the first comparison unit determines that the ionization rate is greater than the reference ionization rate, the adjusted reference current output by the second proportional-integral controller is greater than the reference current, and the first The third comparison unit determines that the adjusted reference current is greater than the reference current, and the third proportional-integral controller controls the output current of the current source to decrease.

In some embodiments, the first comparison unit determines that the ionization rate is smaller than the reference ionization rate, then the adjusted reference current output by the second proportional-integral controller is smaller than the reference current, and the first The third comparison unit determines that the adjusted reference current is smaller than the reference current, and the third proportional-integral controller controls the output current of the current source to increase.

In some embodiments, the first comparison unit determines that the ionization rate is equal to the reference ionization rate, then the adjusted reference current output by the second proportional-integral controller is equal to the reference current, and the first The three comparison units determine that the adjusted reference current is equal to the reference current, and the third proportional-integral controller controls the output current of the current source to remain unchanged.

In some embodiments, the gas dissociation circuit is powered on, that is, the dissociation transformer and the ignition transformer enter a working state, and the ignition gas input control unit is turned on to deliver ignition gas to the dissociation chamber;

The ignition control subunit controls the switch unit to turn off, and the capacitor stores high voltage for ignition;

The ignition control sub-unit detects whether the reference current and the current in the second main coil are equal in magnitude. If the reference current and the current in the second main coil are not equal in magnitude, it means that ignition fails, then Re-ignite until the reference current and the current in the second main coil are equal in magnitude, and then the ignition control sub-unit controls the switch unit to be turned on;

The maintenance gas input control unit is turned on to control the amount of maintenance gas input into the dissociation chamber, and the maintenance gas enters the dissociation chamber. After a threshold time, such as 10s, the output detection unit detects the dissociation The amount of the maintenance gas remaining in the output gas of the chamber, and the calculation unit calculates the ionization according to the amount of the maintenance gas entering the dissociation chamber and the amount of the maintenance gas remaining in the output gas of the dissociation chamber Rate;

The maintenance control subunit adjusts the output current of the current source according to the ionization rate, the reference ionization rate and the reference current.

Although the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes are within the scope and spirit of the invention as set forth in the appended claims. Furthermore, the invention described herein is capable of other embodiments and of being practiced or carried out in various ways.

Claims (10)

1. The gas dissociation circuit based on multi-coil coupling is characterized by comprising at least two dissociation transformers and at least two reactances, wherein each dissociation transformer comprises a first main coil and a first auxiliary coil, the first main coils are connected in series, the first auxiliary coils and the reactances are arranged in a one-to-one correspondence mode, the first auxiliary coils are connected in series, the turn ratios of all the dissociation transformers are the same, and the turn ratio is the ratio of the number of turns of the first main coil to the number of turns of the first auxiliary coil in the same dissociation transformer.

2. The gas dissociation circuit of claim 1, wherein the dissociation transformer further comprises a first magnetic core, the first primary coil and the first secondary coil being wound around an outer side of the first magnetic core.

3. The gas dissociation circuit of claim 1, further comprising an ignition unit comprising an ignition transformer including a second primary winding and a second secondary winding, the second primary winding and the first primary winding being connected in series.

4. The gas dissociation circuit of claim 3, wherein the ignition transformer further comprises a second magnetic core, the second primary winding and the second secondary winding surrounding an outer side of the second magnetic core.

5. The gas dissociation circuit of claim 3, wherein the ignition unit further comprises a capacitance in parallel with the second primary coil.

6. The gas dissociation circuit of claim 3, wherein the ignition unit further comprises an ignition electrode in series with the second sub-coil.

7. The gas dissociation circuit of claim 3, wherein the ignition unit further comprises a switching unit in parallel with the second primary winding.

8. The gas dissociation circuit of claim 7, wherein the switching unit is a power switch.

9. The gas dissociation circuit of claim 1, further comprising a current source in series with the first primary winding.

10. A gas dissociation system, comprising:

a dissociation chamber; and

the gas dissociation circuit of any of claims 1-9, wherein the reactance is disposed within the dissociation chamber.

Images