JPH0711993B2 - Plasma stabilizer - Google Patents
Plasma stabilizerInfo
- Publication number
- JPH0711993B2 JPH0711993B2 JP2328262A JP32826290A JPH0711993B2 JP H0711993 B2 JPH0711993 B2 JP H0711993B2 JP 2328262 A JP2328262 A JP 2328262A JP 32826290 A JP32826290 A JP 32826290A JP H0711993 B2 JPH0711993 B2 JP H0711993B2
- Authority
- JP
- Japan
- Prior art keywords
- plasma
- circuit
- gas pressure
- voltage
- control circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000003381 stabilizer Substances 0.000 title 1
- 239000000523 sample Substances 0.000 claims description 26
- 230000005284 excitation Effects 0.000 claims description 21
- 230000008878 coupling Effects 0.000 claims description 15
- 238000010168 coupling process Methods 0.000 claims description 15
- 238000005859 coupling reaction Methods 0.000 claims description 15
- 238000005259 measurement Methods 0.000 claims description 14
- 238000002955 isolation Methods 0.000 claims description 9
- 238000009529 body temperature measurement Methods 0.000 claims description 4
- 230000000087 stabilizing effect Effects 0.000 claims description 4
- 238000001739 density measurement Methods 0.000 claims description 2
- 230000006641 stabilisation Effects 0.000 claims 1
- 238000011105 stabilization Methods 0.000 claims 1
- 239000007789 gas Substances 0.000 description 28
- 238000000034 method Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 7
- 230000007423 decrease Effects 0.000 description 5
- 238000009413 insulation Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000005215 recombination Methods 0.000 description 2
- 230000006798 recombination Effects 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/0006—Investigating plasma, e.g. measuring the degree of ionisation or the electron temperature
- H05H1/0081—Investigating plasma, e.g. measuring the degree of ionisation or the electron temperature by electric means
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Electromagnetism (AREA)
- Plasma Technology (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 近来プラズマの利用面は益々拡大しており、特にICの製
造設備などでは安定なプラズマ源が要望されている。本
発明は、自動的に安定なプラズマを発生させるプラズマ
安定化装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] Recently, the use of plasma is expanding more and more, and a stable plasma source is demanded especially in IC manufacturing facilities. The present invention relates to a plasma stabilizing device that automatically generates stable plasma.
従来高周波プラズマ装置では、高周波またはマイクロ波
電力およびガス圧を手動によって調整していたので、変
動に対して自動的に追随することができなかった。In the conventional high-frequency plasma device, since the high-frequency or microwave power and the gas pressure were manually adjusted, it was not possible to automatically follow the fluctuation.
〔課題を解決するための手段〕 本発明は、トリプル・プローブ法を用いて、プラズマの
電子温度および電子密度を直接指示系計器に表示せし
め、この出力を用いて高周波またはマイクロ波電力量お
よびガス圧をそれぞれ単独もしくはそれらを同時に制御
することによって、安定なプラズマを発生せしめるプラ
ズマ安定装置である。[Means for Solving the Problems] The present invention uses the triple probe method to display the electron temperature and electron density of plasma directly on an indicating system instrument, and uses this output to output high-frequency or microwave power and gas. It is a plasma stabilizing device that generates stable plasma by controlling the pressures individually or simultaneously.
この際電子温度および電子密度の測定回路は、直流的に
浮動しているので対接地電圧として出力しなければなら
ない。この出力制御電圧によって高周波またはマイクロ
波電力およびガス圧を制御し、プラズマ炎を安定にす
る。At this time, the circuit for measuring the electron temperature and the electron density must be output as a voltage to ground because it floats in the direct current. The output control voltage controls high frequency or microwave power and gas pressure to stabilize the plasma flame.
すなわち、本発明は、トリプル・プローブによってプラ
ズマの電子温度および電子密度を測定する測定回路、電
子温度測定出力信号によってプラズマガス圧を制御する
ガス圧制御回路、電子密度制定出力信号によってプラズ
マ励振電力を制御する電力制御回路、該測定回路と該ガ
ス圧制御回路及び該電力制御回路とをそれぞれ結合する
絶縁結合素子とで構成され、プラズマガス圧、プラズマ
励振電力の少なくとも一方を制御して自動的に安定なプ
ラズマを発生させるプラズマ安定化装置である。又、絶
縁結合素子を用いない場合は、上記の測定回路から電子
温度測定出力信号および電子密度測定出力信号に相当す
る対接地電圧をそれぞれ取り出し、それらによってガス
圧制御回路、電子制御回路を制御してもよい。That is, the present invention provides a measurement circuit for measuring the electron temperature and electron density of plasma by a triple probe, a gas pressure control circuit for controlling plasma gas pressure by an electron temperature measurement output signal, and a plasma excitation power by an electron density establishment output signal. A power control circuit for controlling, a measuring circuit, and an insulating coupling element for respectively coupling the gas pressure control circuit and the power control circuit, and automatically controlling by controlling at least one of plasma gas pressure and plasma excitation power. It is a plasma stabilizing device that generates stable plasma. When the insulated coupling element is not used, the isolation voltage corresponding to the electron temperature measurement output signal and the electron density measurement output signal are respectively taken out from the above measurement circuit, and the gas pressure control circuit and the electronic control circuit are controlled by them. May be.
トリプル・プローブ法によるプラズマ特性検出回路は、
出力が直流的に浮いているので、信号を外部に取り出す
ためには、直流的に絶縁して接続する必要がある。本発
明では、アイソレーション・アンプや電圧周波数変換回
路、光アイソレータ等による絶縁結合素子を使用して、
直流的には絶縁しても制御信号は外部回路に伝達させる
方式および電子回路によってそれらの出力電圧に相当す
る対接地電圧を取り出す方式を創作した。電子温度Te出
力信号をガス圧制御回路に導いて、ガス圧を制御し、ま
た電子密度Neの出力信号で高周波またはマイクロ波出力
電力を制御することによって、自動的にプラズマ炎を安
定にする。The plasma characteristic detection circuit by the triple probe method is
Since the output floats in terms of direct current, it is necessary to insulate and connect to direct current in order to take out the signal to the outside. In the present invention, an isolation amplifier, a voltage frequency conversion circuit, an insulating coupling element such as an optical isolator is used,
We created a method of transmitting a control signal to an external circuit even if insulated from a direct current, and a method of extracting an isolation voltage corresponding to those output voltages by an electronic circuit. By guiding the electron temperature Te output signal to the gas pressure control circuit to control the gas pressure and controlling the high frequency or microwave output power with the electron density Ne output signal, the plasma flame is automatically stabilized.
プラズマ内の電子密度は、単位時間内に電離によって生
ずる電子の数と、再結合によって消滅する電子の数の差
によって決まる。電子エネルギーの比較的に低い一般の
プラズマ領域では、電子エネルギーの増加即ち印加高周
波またはマイクロ波励振電力の増加によって電離確率が
増大する一方、再結合係数が減少するので、結果として
電子密度Neが増大する。The electron density in plasma is determined by the difference between the number of electrons generated by ionization in a unit time and the number of electrons extinguished by recombination. In the general plasma region where the electron energy is relatively low, the ionization probability increases as the electron energy increases, that is, the applied high frequency or microwave excitation power increases, while the recombination coefficient decreases, resulting in an increase in the electron density Ne. To do.
電子は高周波電力励振によって運動エネルギーを得る一
方、原子または分子との衝突によってエネルギーを失
い、単位時間に得失するエネルギーの差によって電子温
度Teが決まる。While electrons gain kinetic energy by high-frequency power excitation, they lose energy by collision with atoms or molecules, and the electron temperature Te is determined by the difference in energy gained and lost per unit time.
これらの電子密度Neと電子温度Teは印加高周波またはマ
イクロ波励振電力およびガス圧によって共に変化する
が、トリプル・プローブ法によって電子密度Neと電子温
度Teとを直読しつつ実験したところ、励振電力の増加に
よって電子密度Neの指示は大きな増加を見せたが、電子
温度Teの指示はわずかな増加にすぎなかった。またガス
圧の増加に対しては、電子温度Teの指示が著しい減少を
示し、電子密度Neの変化は微小であった。The electron density Ne and the electron temperature Te both change depending on the applied high frequency or microwave excitation power and the gas pressure, but an experiment was conducted while directly reading the electron density Ne and the electron temperature Te by the triple probe method. The electron density Ne showed a large increase with the increase, but the electron temperature Te showed only a small increase. The electron temperature Te showed a marked decrease with increasing gas pressure, and the change in electron density Ne was small.
そこで本発明では、電子温度Teの指示電圧出力に相当す
る電圧をガス制御回路に導き、電磁バルブを調整してガ
ス圧を制御し、また電子密度Neの出力電圧に相当する電
圧を電力制御回路に入れ、高周波またはマイクロ波出力
電力を制御して、プラズマ炎を安定にした。Therefore, in the present invention, a voltage corresponding to the indicated voltage output of the electron temperature Te is introduced to the gas control circuit, the electromagnetic valve is adjusted to control the gas pressure, and the voltage corresponding to the output voltage of the electron density Ne is changed to the power control circuit. And controlled the high frequency or microwave output power to stabilize the plasma flame.
これらのガス圧による自動制御や励振高周波またはマイ
クロ波電力による自動制御は単独で実施しても効果があ
るが、同時に両者による制御を行えば、安定効果が著し
く上昇する。The automatic control by the gas pressure and the automatic control by the excitation high frequency or the microwave power are effective even if they are independently performed, but the stability effect is remarkably increased if the control by both is performed at the same time.
トリプル・プローブ法の測定原理と測定法については、
内田老鶴圃版、堤井信力書『プラズマ基礎工学』168乃
至183頁に詳述されているが、NeとTeとを直読で読み取
るには、プラズマ内に表面積が等しい３個のプローブ
P1、P2、P3を接近させて挿入し、第３図のようにP2の負
荷に入力インピーダンスの高い電圧計（Te測定回路）を
接続して、プローブを浮動状態にすると、P2に流れる電
流はゼロとなる。この時電子の電荷をe,kをボルツマン
定数、プローブP1とP2の間に発生する差電圧をVd2、プ
ローブP3に加える一定電圧をVd3とし、プローブP3からP
1に流れる電流Ｉの低抵抗Ｒ両端に生ずる電圧降下を電
子密度Ne測定回路で求めるようにすると、次式のような
関係になる。For the measurement principle and method of the triple probe method,
Uchida Otsuru-Kaku version, Noboru Tsutsui's book "Plasma Fundamental Engineering", pages 168 to 183. Ne and Te can be read directly by three probes with the same surface area in the plasma.
P 1, P 2, and insert to approximate P 3, with a high voltmeter input impedance to the load P 2 as in the third diagram the (Te measuring circuit) connected, when the probe to float, P The current flowing through 2 becomes zero. At this time, let e, k be the Boltzmann constants, Vd2 be the voltage difference generated between the probes P 1 and P 2 , and V d3 be the constant voltage applied to the probe P 3 at this time.
If the voltage drop across the low resistance R of the current I flowing through 1 is determined by the electron density Ne measurement circuit, the following relationship is established.
｛１−exp（−φd2）｝／｛１−exp（−φd3）｝＝1/2 上式中 φd2＝eVd2/kTe φd3＝eVd3/kTe である。従ってVd3を一定値とすると、Vd2を測定するこ
とによりTeが求められる。{1-exp (−φ d2 )} / {1-exp (−φ d3 )} = 1/2 In the above equation, φ d2 = eV d2 / kTe φ d3 = eV d3 / kTe. Therefore, if V d3 is a constant value, Te can be obtained by measuring V d2 .
この式は測定範囲でのイオン電流の変化が小さいとして
いるが、無衝突プラズマ中における円筒プローブのイオ
ン電流は、理論的にプローブ電圧の（1/2）乗に比例し
て増加するので、浮動電圧Vfにおけるイオン電流I
i（Vf）を基準として、定数βを使って電圧Ｖにおける
イオン電流Ii（Ｖ）を表すと、次のようになる。This formula assumes that the change in ion current in the measurement range is small, but since the ion current of a cylindrical probe in collisionless plasma theoretically increases in proportion to the (1/2) th power of the probe voltage, it floats. Ion current I at voltage V f
When the ion current I i (V) at the voltage V is expressed using the constant β with reference to i (V f ), it becomes as follows.
｛Ii(V)}2＝｛Ii(Vf)}2（１＋βΔＶ） この様にイオン電流が変化するとして、Vd3＝10ボルト
一定のとき、種々のβに対して電子温度Teを求めると第
４図のようになる。{I i (V)} 2 = {I i (V f )} 2 (1 + βΔV) Assuming that the ionic current changes in this way, when V d3 = 10 V is constant, the electron temperature Te is changed for various β. The result is shown in Fig. 4.
実験によれば、β＝1.05とすると一般のプラズマ測定で
Teの誤差が数％以内に収まっていることが判った。According to the experiment, if β = 1.05, it is
It was found that the Te error was within a few percent.
電子密度Neについては、同書（172頁）で次のように与
えられている。The electron density Ne is given in the same book (page 172) as follows.
Ne＝(N1/2/S)・I・f1(Vd2) f1(Vd2)＝1.05×109×(Te)-1/2／｛exp（−φd2）−
１｝ 用いられている単位は、Ne（cm−３），プローブの表面
積（mm2,I（μＡ）,Te（eV）,M（イオンの原子量または
分子量）、Vd2（Ｖ）である。以上の両式からＭとＳを
与えれば、プローブ電流ＩとTeおよびVd2から電子密度N
eが求められ、出力計器でこの値が直読できる。Ne ＝ (N 1/2 / S) ・ I ・ f 1 (V d2 ) f 1 (V d2 ) ＝ 1.05 × 10 9 × (Te) -1/2 / {exp (−φ d2 ) −
1} The units used are Ne (cm −3 ), surface area of the probe (mm 2 , I (μA), Te (eV), M (atomic or molecular weight of ion), V d2 (V). If M and S are given from the above equations, the electron density N from the probe currents I, Te and V d2
e is calculated, and this value can be directly read by the output meter.
以上の原理で求められた電子温度Teに相当する出力電圧
で計器を指示させると共に、絶縁結合素子を介して直流
を遮断するか、あるいは電子回路によって接地点に対す
る出力相当電圧を求め、この出力電圧をガス制御回路で
増幅し、電磁バルブを制御してガス圧を増減する。即ち
Teが高過ぎれば、ガス圧を増加させてTeを低下させ、反
対にTeが低過ぎれば、ガス圧を減少させてTeを上昇させ
る。The output voltage corresponding to the electron temperature Te obtained by the above principle is used to indicate the instrument, and the direct current is cut off via an insulating coupling element, or the output equivalent voltage to the ground point is obtained by an electronic circuit, and this output voltage Is amplified by the gas control circuit and the electromagnetic valve is controlled to increase or decrease the gas pressure. I.e.
If Te is too high, the gas pressure is increased to decrease Te, and if Te is too low, the gas pressure is decreased to increase Te.
一方、電子密度Neの計器出力電圧も同様に接地点に対す
る出力相当電圧を求め、これを励振電力制御回路に導
き、高周波またはマイクロ波発生源の出力電力を増減し
て、プラズマの励振電力を制御する。即ち電子密度Neが
過大ならば、励振電力を低下させて密度を下げ、逆なら
ば励振電力を増加させて電子密度を上昇させる。この様
にしてプラズマ炎を自動的に安定に保つ事ができる。On the other hand, similarly for the instrument output voltage of the electron density Ne, obtain the output equivalent voltage to the ground point, guide it to the excitation power control circuit, and increase or decrease the output power of the high frequency or microwave generation source to control the plasma excitation power. To do. That is, if the electron density Ne is excessive, the excitation power is reduced to reduce the density, and if the electron density Ne is opposite, the excitation power is increased to increase the electron density. In this way, the plasma flame can be automatically kept stable.
第１図は本発明の実施例の系統図を示している。プラズ
マ・チェンバー１には試料ガスが電磁バルブ５を経由し
て供給され、マイクロ波電力が結合孔６から導入されて
プラズマ２が発生している。このプラズマ内に表面積の
等しい３個のプローブ３が挿入され、第３図のトリプル
・プローブ法原理説明図に示されているようにプローブ
P2は電子温度Te測定回路８で増幅後、指示計９にTeの値
を指示している。プローブP3には固定定電圧Vd3電源13
から10ボルトの負電圧が加えられていて、プローブP3か
らP1に流れる電流Ｉの１オームの微小抵抗器12に生ずる
電圧降下をNe測定回路10で、Teの出力電圧と共に計算し
て、電子密度Neに相当する電圧を求め、指示計11にNeの
量を示す。FIG. 1 shows a system diagram of an embodiment of the present invention. A sample gas is supplied to the plasma chamber 1 via an electromagnetic valve 5, and microwave power is introduced from a coupling hole 6 to generate plasma 2. Three probes 3 having the same surface area are inserted into this plasma, and the probes are arranged as shown in the triple probe method principle explanatory diagram of FIG.
After P 2 is amplified by the electron temperature Te measuring circuit 8, the value of Te is indicated on the indicator 9. Fixed constant voltage V d3 power supply 13 for probe P 3
10 volts negative voltage is not applied from the voltage drop across the 1 ohm micro resistor 12 of the current I flowing from the probe P 3 to P 1 in Ne measuring circuit 10, calculated with the output voltage of Te, The voltage corresponding to the electron density Ne is obtained, and the indicator 11 shows the amount of Ne.
Te測定回路８の出力電圧は直流的に浮かさなければなら
ないので、絶縁結合素子として絶縁増幅器151を使い、
次段のガス制御回路16に制御電圧を加えて、電磁バルブ
５を調節して試料ガスの圧力を制御する。Since the output voltage of the Te measurement circuit 8 must be floated in a DC manner, the isolation amplifier 151 is used as an isolation coupling element,
A control voltage is applied to the gas control circuit 16 in the next stage to adjust the electromagnetic valve 5 to control the pressure of the sample gas.
絶縁結合素子としては、絶縁増幅151のほか光アイソレ
ータや電圧周波数変換器を使用する絶縁法や、直流電圧
を交流に変換後絶縁変成器を使って結合させてから、再
び直流に戻す方法などが使用できる。As the insulating coupling element, in addition to the insulation amplification 151, an insulation method using an optical isolator or a voltage frequency converter, a method of converting a DC voltage into an AC voltage and then coupling with an insulation transformer, and then returning to a DC voltage again can be used. Can be used.
Ne測定回路10の出力電圧も同様の絶縁結合素子として絶
縁増幅器152を使って、その出力を励振電力制御回路17
に加え、2.45GHzマイクロ波電源７の電力を調整してプ
ラズマに加えられる励振電力を制御して、プラズマ炎２
を安定にする。これらに必要な交流電力は、絶縁変圧器
14を経て加えられる。The output voltage of the Ne measurement circuit 10 uses an isolation amplifier 152 as a similar isolation coupling element, and its output is driven by the excitation power control circuit 17
In addition, the power of the 2.45 GHz microwave power supply 7 is adjusted to control the excitation power applied to the plasma, and the plasma flame 2
To stabilize. The AC power required for these is an isolation transformer.
Added after 14
本発明の他の実施例として、第１図の絶縁結合素子に代
わる部分を第２図に抽出して示す。Te測定回路８の出力
電位をV1,Ne測定回路10の出力電位をV2,Vd3定電圧電源1
3の＋端子電位をV3とすると、第１図と同様にTe出力指
示計はV1とV3の差電圧に比例して振れ、またNe出力指示
計はV2とV3の差電圧に比例して振れている。As another embodiment of the present invention, a portion replacing the insulating coupling element of FIG. 1 is extracted and shown in FIG. Output potential of Te measurement circuit 8 is V1, Output potential of Ne measurement circuit 10 is V2, V d3 Constant voltage power supply 1
Assuming that the + terminal potential of 3 is V3, the Te output indicator swings in proportion to the difference voltage between V1 and V3, and the Ne output indicator swings in proportion to the difference voltage between V2 and V3 as in Fig. 1. ing.
V1電位は差動増幅器211の正極入力端子に接続されこの
出力は２段のインバータ221・231で増幅され、その出力
が差動増幅器211の負極入力端子に戻されているので、
インバータ231の出力電位V1′がV1に等しくなったとこ
ろで平衡状態になる。The V1 potential is connected to the positive input terminal of the differential amplifier 211, the output is amplified by the two-stage inverters 221, 231 and the output is returned to the negative input terminal of the differential amplifier 211.
The equilibrium occurs when the output potential V1 ′ of the inverter 231 becomes equal to V1.
電位V2とV3も同様の差動増幅器212・213およびインバー
タ222・232・223・233で増幅され、それらの出力V2′と
V3′は入力電位V2とV3に等しくなっている。The potentials V2 and V3 are also amplified by the same differential amplifiers 212, 213 and inverters 222, 232, 223, 233 and their outputs V2 'and
V3 'is equal to the input potentials V2 and V3.
次段の差動増幅器241にはV1′とV3′の電位が加えられ
るので、その出力はV1′とV3′の差電圧即ちTe指示電圧
に相当する対接地点電圧になり、絶縁結合素子を使用し
なくもTe測定回路から絶縁した出力電圧が得られる。そ
こでこのTe相当制御電圧をガス制御回路16に加えて電磁
バルブ５を調整して、試料ガスの圧力を制御してプラズ
マ炎を安定にする。Since the potentials of V1 ′ and V3 ′ are applied to the differential amplifier 241 in the next stage, the output thereof becomes the difference voltage between V1 ′ and V3 ′, that is, the voltage to ground point corresponding to the Te indicating voltage, and the isolated coupling element is connected. An isolated output voltage can be obtained from the Te measurement circuit without using it. Therefore, this Te equivalent control voltage is applied to the gas control circuit 16 to adjust the electromagnetic valve 5 to control the pressure of the sample gas and stabilize the plasma flame.
差動増幅器242にはV2′とV3′の電位を加えるので、出
力はV2′とV3′の差電圧即ちNe指示電圧に相当する対接
地点電圧になり、絶縁結合素子を使用しなくともNe測定
回路から絶縁された出力電圧が得られる。このNe相当制
御電圧を励振電力制御回路17に加えて、マイクロ波電源
の出力電力を調整し、プラズマの励振電力を制御してプ
ラズマ炎を安定にする。Since the potentials of V2 'and V3' are applied to the differential amplifier 242, the output becomes the voltage difference between V2 'and V3', that is, the voltage to the ground point corresponding to the Ne indicating voltage, and Ne does not need to use an insulating coupling element. An isolated output voltage is obtained from the measuring circuit. This Ne equivalent control voltage is applied to the excitation power control circuit 17 to adjust the output power of the microwave power source and control the excitation power of the plasma to stabilize the plasma flame.
第２図中、191・192および193はいずれも短絡防止用の
抵抗器で、差動増幅器回路が平衡に達するまでの間、入
力負荷インピーダンスの低下による悪影響が前段に及ぶ
ことを防いでいるが、平衡時には入力負荷インピーダン
スが高くなるので、この抵抗器による電圧降下は問題に
ならない。また201、202および203は入力端子抵抗器で
ある。In FIG. 2, 191, 192, and 193 are all short-circuit preventing resistors, which prevent the adverse effect of the reduction of the input load impedance from reaching the preceding stage until the differential amplifier circuit reaches the balance. Since the input load impedance becomes high at equilibrium, the voltage drop due to this resistor is not a problem. Also, 201, 202 and 203 are input terminal resistors.
プラズマの不安定要素は非常に多岐に亘っていて、その
全部を除くことは出来ないが、本発明を実施することに
よって大いに改善できる。ガス圧力や高周波励振電力の
みを単独に本発明による自動制御を実施しても相当の効
果があげられるが、両者を同時に行えば、安定度を一桁
改善できた。実験では、水素ガス中に10％のメタンガス
を混入させた試料を0.2Torrの気圧として使い、2.45GHz
300Wのマイクロ波励振電力を加えて、プラズマを発生さ
せて４時間の連続運転を試みたが、この間非常に安定に
動作を継続した。The plasma instability factors are very diverse and cannot be eliminated in their entirety, but they can be greatly improved by implementing the present invention. Even if the automatic control according to the present invention is performed by using only the gas pressure and the high frequency excitation power independently, a considerable effect can be obtained, but if both are performed at the same time, the stability can be improved by one digit. In the experiment, a sample in which 10% methane gas was mixed in hydrogen gas was used as a pressure of 0.2 Torr, and 2.45 GHz was used.
Microwave was generated by applying 300W microwave excitation power, and continuous operation was attempted for 4 hours. During this time, the operation continued very stably.
第１図は本発明の実施例系統図、第２図は他の実施例の
系統図、第３図はトリプル・プローブ法の原理説明図、
第４図はVd2電圧対電子温度Te特性図である。 １はプラズマ・チェンバー、２はプラズマ炎、３はプロ
ーブ、４はガス流入口、５は電磁バルブ、６は励振電力
結合孔、７は高周波またはマイクロ波電源、８はTe測定
回路、９はTe出力指示計、10はNe測定回路、11はNe出力
指示計、12は微小抵抗器、13はVd3定電圧電源、14は絶
縁変圧器、151・152は絶縁増幅器、16はガス制御回路、
17は励振電力制御回路、191・192・193は短絡防止用抵
抗器、201・202・203は入力端子抵抗器、211・212・213
および241・242は差動増幅器、221・222・223・231・23
2・233はインバータ。FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a system diagram of another embodiment, and FIG. 3 is an explanatory diagram of the principle of the triple probe method.
FIG. 4 is a V d2 voltage vs. electron temperature Te characteristic diagram. 1 is a plasma chamber, 2 is a plasma flame, 3 is a probe, 4 is a gas inlet, 5 is an electromagnetic valve, 6 is an exciting power coupling hole, 7 is a high frequency or microwave power source, 8 is a Te measurement circuit, and 9 is Te. Output indicator, 10 Ne measurement circuit, 11 Ne output indicator, 12 micro resistor, 13 V d3 constant voltage power supply, 14 insulation transformer, 151/152 insulation amplifier, 16 gas control circuit,
17 is the excitation power control circuit, 191, 192, 193 are short-circuit prevention resistors, 201, 202, 203 are input terminal resistors, 211, 212, 213
And 241, 242 are differential amplifiers, 221, 222, 223, 231, 23
2 ・ 233 is an inverter.
Claims (2)
子温度および電子密度を測定する測定回路、電子温度測
定出力信号によってプラズマガス圧を制御するガス圧制
御回路、電子密度制定出力信号によってプラズマ励振電
力を制御する電力制御回路、該測定回路と該ガス圧制御
回路及び該電力制御回路とをそれぞれ結合する絶縁結合
素子とで構成され、プラズマガス圧、プラズマ励振電力
の少なくとも一方を制御して自動的に安定なプラズマを
発生させるプラズマ安定化装置。1. A measurement circuit for measuring electron temperature and electron density of plasma by a triple probe, a gas pressure control circuit for controlling plasma gas pressure by an electron temperature measurement output signal, and a plasma excitation power by an electron density establishment output signal. Power control circuit, the measurement circuit, the gas pressure control circuit, and an insulating coupling element that couples the power control circuit, respectively, and controls at least one of plasma gas pressure and plasma excitation power to automatically stabilize. Stabilization device that generates a stable plasma.
子温度および電子密度を測定する測定回路、電子温度測
定出力信号および電子密度測定出力信号にそれぞれ相当
する対接地電圧を取り出す回路、該回路からの信号によ
ってプラズマガス圧、プラズマ励振電力をそれぞれ制御
するガス圧制御回路、電力制御回路とで構成され、プラ
ズマガス圧、プラズマ励振電力の少なくとも一方を制御
して自動的に安定なプラズマを発生させるプラズマ安定
装置。2. A measuring circuit for measuring an electron temperature and an electron density of plasma by a triple probe, a circuit for extracting an isolation voltage corresponding to each of an electron temperature measurement output signal and an electron density measurement output signal, and a signal from the circuit. A plasma stabilizing device configured by a gas pressure control circuit and a power control circuit for controlling plasma gas pressure and plasma excitation power, respectively, and automatically generating stable plasma by controlling at least one of plasma gas pressure and plasma excitation power. .
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2328262A JPH0711993B2 (en) | 1990-11-28 | 1990-11-28 | Plasma stabilizer |
| US07/915,809 US5365147A (en) | 1990-11-28 | 1991-11-26 | Plasma stabilizing apparatus employing feedback controls |
| PCT/JP1991/001617 WO1992010076A1 (en) | 1990-11-28 | 1991-11-26 | Plasma stabilizer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2328262A JPH0711993B2 (en) | 1990-11-28 | 1990-11-28 | Plasma stabilizer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04206198A JPH04206198A (en) | 1992-07-28 |
| JPH0711993B2 true JPH0711993B2 (en) | 1995-02-08 |
Family
ID=18208260
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2328262A Expired - Fee Related JPH0711993B2 (en) | 1990-11-28 | 1990-11-28 | Plasma stabilizer |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH0711993B2 (en) |
| WO (1) | WO1992010076A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105744711B (en) * | 2016-04-15 | 2018-01-23 | 中国人民解放军装甲兵工程学院 | A kind of thermal ionization plasma generation test device and its density measurement and control method |
| JP6890459B2 (en) * | 2017-04-14 | 2021-06-18 | 東京エレクトロン株式会社 | Plasma processing equipment and control method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54135574A (en) * | 1978-03-23 | 1979-10-20 | Japan Synthetic Rubber Co Ltd | Probe for measuring characteristics of plasma* and method and device employing said probe |
-
1990
- 1990-11-28 JP JP2328262A patent/JPH0711993B2/en not_active Expired - Fee Related
-
1991
- 1991-11-26 WO PCT/JP1991/001617 patent/WO1992010076A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO1992010076A1 (en) | 1992-06-11 |
| JPH04206198A (en) | 1992-07-28 |
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