JPH0232352B2 - - Google Patents
Info
- Publication number
- JPH0232352B2 JPH0232352B2 JP59012578A JP1257884A JPH0232352B2 JP H0232352 B2 JPH0232352 B2 JP H0232352B2 JP 59012578 A JP59012578 A JP 59012578A JP 1257884 A JP1257884 A JP 1257884A JP H0232352 B2 JPH0232352 B2 JP H0232352B2
- Authority
- JP
- Japan
- Prior art keywords
- flow rate
- signal
- pressure
- deviation
- vacuum
- 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 - Lifetime
Links
- 239000007789 gas Substances 0.000 description 17
- 238000010586 diagram Methods 0.000 description 4
- 238000012423 maintenance Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 229910003902 SiCl 4 Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010574 gas phase reaction Methods 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/52—Controlling or regulating the coating process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
- B01J3/006—Processes utilising sub-atmospheric pressure; Apparatus therefor
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/54—Controlling or regulating the coating process
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- General Chemical & Material Sciences (AREA)
- Plasma Technology (AREA)
- Physical Vapour Deposition (AREA)
- Chemical Vapour Deposition (AREA)
Description
【発明の詳細な説明】
この発明は、真空槽の真空雰囲気をガスの導入
流量および圧力のいずれを基準にしても制御する
ことのできる真空雰囲気制御装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum atmosphere control device that can control the vacuum atmosphere of a vacuum chamber based on both the flow rate and pressure of gas introduced.
真空槽内にAr，O2，N2，SiH4，SiCl4などの
ガスを導入して真空雰囲気を調整することは、ス
パツタリング装置、イオンプレーテイング装置、
反応性真空蒸着装置、プラズマ発生装置など広く
行なわれている。このような装置においては、真
空槽内の圧力を基準として、あるいはガス流量を
一定にして真空槽内にガスが導入されており、自
動圧力調整器（APC）や自動流量調整器（AFC）
が用いられてきた。 Adjusting the vacuum atmosphere by introducing gases such as Ar, O 2 , N 2 , SiH 4 , and SiCl 4 into the vacuum chamber is performed using sputtering equipment, ion plating equipment,
It is widely used in reactive vacuum evaporation equipment, plasma generation equipment, etc. In such devices, gas is introduced into the vacuum chamber based on the pressure inside the vacuum chamber or with a constant gas flow rate, and automatic pressure regulators (APC) and automatic flow regulators (AFC) are used to introduce gas into the vacuum chamber.
has been used.
しかしながら、形成すべき薄膜の種類、気相反
応の種類、放電条件などによつて、あるいは繰返
し使用による真空槽内の排出ガス量の変化を考慮
すると、所望の薄膜特性などを得るためには、圧
力を基準にしてガスを導入し真空雰囲気を制御す
るのが適当である場合と、流量を基準としてガス
を導入して真空雰囲気を制御するのが好ましい場
合とがあることが判つてきた。この要請を満足し
て双方の制御を可能にするには、自動圧力調整器
と自動流量調整器の２つの調整器を１つの真空槽
に設けることが必要となるが、それぞれの調整器
に関してガス導入口やガス流量制御バルブを要す
ることから、装置が複雑、高価となるばかりか、
リークが発生する原因となる個所も多くなり、保
守管理も煩雑となるという問題が生じる。 However, depending on the type of thin film to be formed, the type of gas phase reaction, discharge conditions, etc., or considering changes in the amount of exhaust gas in the vacuum chamber due to repeated use, in order to obtain desired thin film characteristics, etc. It has been found that there are cases in which it is appropriate to introduce gas and control the vacuum atmosphere based on pressure, and there are cases in which it is preferable to introduce gas and control the vacuum atmosphere based on flow rate. In order to satisfy this request and enable control of both, it is necessary to install two regulators, an automatic pressure regulator and an automatic flow regulator, in one vacuum chamber. Since an inlet and a gas flow control valve are required, the equipment is not only complicated and expensive, but also
Problems arise in that the number of locations where leaks occur increases and maintenance management becomes complicated.
この発明はこのような観点からなされたもので
あり、使用目的によつて、圧力あるいはガス流量
のいずれを基準としても簡便に真空雰囲気を調整
することのできる真空雰囲気制御装置を提供する
ことを目的とする。 The present invention has been made from this point of view, and an object thereof is to provide a vacuum atmosphere control device that can easily adjust the vacuum atmosphere based on either pressure or gas flow rate depending on the purpose of use. shall be.
すなわち、この発明の真空雰囲気制御装置は、
流量センサからの出力信号と設定流量信号とを比
較し偏差を検知して第１の動作信号を出力し、真
空計からの出力信号と設定圧力信号とを比較し偏
差を検知して第２の動作信号を出力する比較回路
と、
真空槽へのガス流量を調整する流量調整バルブ
と、
前記第１または第２の動作信号を受けて偏差量
が許容量以下となるように前記流量制御バルブの
開度を制御する制御機構と、
前記第１または第２の動作信号を選択的に前記
制御機構に供給する信号切換機構とを有すること
を特徴とする。 That is, the vacuum atmosphere control device of the present invention:
The output signal from the flow rate sensor and the set flow rate signal are compared, a deviation is detected, and a first operation signal is output; the output signal from the vacuum gauge and the set pressure signal are compared, a deviation is detected, and a second operation signal is output. a comparison circuit that outputs an operation signal; a flow rate adjustment valve that adjusts the gas flow rate to the vacuum chamber; It is characterized by comprising: a control mechanism that controls the opening degree; and a signal switching mechanism that selectively supplies the first or second operation signal to the control mechanism.
以下、添付図面に沿つてこの発明をさらに詳細
に説明する。 Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.
第１図はこの発明の実施例を示す説明図であ
り、真空ポンプにより排気される真空槽１１には
流量制御バルブ１３が設けられ、このバルブ１３
の開度を制御することによりライン１５からライ
ン１７を経て所望の流量で真空槽１１にガスを供
給するようになつている。 FIG. 1 is an explanatory diagram showing an embodiment of the present invention, in which a vacuum tank 11 that is evacuated by a vacuum pump is provided with a flow rate control valve 13.
Gas is supplied to the vacuum chamber 11 from the line 15 through the line 17 at a desired flow rate by controlling the opening degree.
流量センサ２１、第１の比較回路２３および流
量設定回路２５は流量制御システムを構成する。
切換スイツチ２７の接点２７ａ，２７ｂとが接続
されて流量モードとなると、流量設定回路２５で
ポテンシヨメータなどにより設定された電圧とし
て、流量設定回路２５から設定流量信号が第１の
比較回路２３に送られる。第１の比較回路２３で
は流量計２１からの流量出力信号と設定流量信号
とが比較されて偏差が検知され、第１の比較回路
２３から偏差に応じて第１の動作信号が出力さ
れ、この動作信号によりサーボモータなどのバル
ブ作動部材１９が作動して、設定流量信号と流量
出力信号との偏差量が零以下となるように制御バ
ルブ１３の開度が調節される。 The flow rate sensor 21, the first comparison circuit 23, and the flow rate setting circuit 25 constitute a flow rate control system.
When the contacts 27a and 27b of the changeover switch 27 are connected to enter the flow rate mode, a set flow rate signal is sent from the flow rate setting circuit 25 to the first comparison circuit 23 as a voltage set by a potentiometer or the like in the flow rate setting circuit 25. Sent. The first comparison circuit 23 compares the flow rate output signal from the flowmeter 21 and the set flow rate signal to detect a deviation, and the first comparison circuit 23 outputs a first operation signal according to the deviation. A valve operating member 19 such as a servo motor is actuated by the operation signal, and the opening degree of the control valve 13 is adjusted so that the amount of deviation between the set flow rate signal and the flow rate output signal is equal to or less than zero.
一方、真空計２９、第２の比較回路３１および
圧力設定回路３３は圧力制御システムを構成す
る。切換えスイツチ２７の接点２７ａと２７ｃと
が接続されて圧力モードとなると、圧力設定回路
３３でポテンシヨメータなどにより設定され電圧
として、圧力設定回路３３から設定圧力信号が第
２の比較回路３１に送られる。第２の比較回路３
１では真空計２９からの圧力出力信号と設定圧力
信号とが比較されて、偏差が検知され第２の比較
回路３１から偏差に応じて第２の動作信号が出力
され、この動作信号によりバルブ作動部材１９が
作動して、設定圧力信号と圧力出力信号との偏差
量が零になるように流量制御バルブ１３の開度が
調整される。この圧力制御システムでは流量制御
バルブの開度をPID制御することが好ましい。 On the other hand, the vacuum gauge 29, the second comparison circuit 31, and the pressure setting circuit 33 constitute a pressure control system. When the contacts 27a and 27c of the changeover switch 27 are connected to enter the pressure mode, a set pressure signal is set by a potentiometer or the like in the pressure setting circuit 33 and sent as a voltage to the second comparison circuit 31. It will be done. Second comparison circuit 3
1, the pressure output signal from the vacuum gauge 29 and the set pressure signal are compared, a deviation is detected, and a second operation signal is output from the second comparison circuit 31 according to the deviation, and this operation signal causes the valve to operate. The member 19 operates to adjust the opening degree of the flow rate control valve 13 so that the amount of deviation between the set pressure signal and the pressure output signal becomes zero. In this pressure control system, it is preferable to PID control the opening degree of the flow rate control valve.
また、上記実施例では第１および第２の２つの
比較回路を用いて、それぞれ流量制御システムお
よび圧力制御システムを作動せしめる場合につい
て説明したが１つの比較回路により流量出力信号
と設定流量信号との比較および圧力出力信号、設
定圧力信号との比較の双方を行なうようにしても
よい。第２図はその実施例を示すブロツク図であ
り、第１図の第１および第２の比較回路の代りに
比較回路２４を用いて切換えスイツチ２８，３０
の接続位置を変更した以外は第１図に示したもの
と同様である。切換えスイツチ２８，３０におい
てそれぞれ接点２８ａと接点２８ｂ、接点３０ａ
と接点３０ｂとが接続されると流量設定回路２５
からの設定流量信号が比較回路２４に送られ、こ
の信号と流量センサ２１からの出力信号が比較さ
れて偏差が検知され、比較回路２４から第１の動
作信号が出力されてバルブ作動部材１９により流
量制御バルブ１３の開度が制御される。一方、切
換えスイツチ２８，３０のそれぞれ接点２８ａと
接点２８ｃ、接点３０ａと接点３０ｃとが接続さ
れると、真空計２９の出力信号が比較回路２４に
入力され、この信号と圧力設定回路３３からの設
定圧力信号とが比較されて第２の動作信号が出力
され、流量調整バルブ１３の開度が制御される。 Further, in the above embodiment, the case where the first and second comparison circuits are used to operate the flow rate control system and the pressure control system, respectively, is explained, but one comparison circuit is used to compare the flow rate output signal and the set flow rate signal. Both the comparison and the comparison with the pressure output signal and the set pressure signal may be performed. FIG. 2 is a block diagram showing this embodiment, in which a comparator circuit 24 is used in place of the first and second comparator circuits in FIG.
It is the same as that shown in FIG. 1 except that the connection position of is changed. In the changeover switches 28 and 30, contacts 28a, 28b, and 30a are provided, respectively.
When the contact point 30b is connected, the flow rate setting circuit 25
A set flow rate signal from the flow rate sensor 21 is sent to the comparator circuit 24, this signal is compared with the output signal from the flow rate sensor 21 to detect a deviation, and the comparator circuit 24 outputs a first operating signal, which is activated by the valve actuating member 19. The opening degree of the flow control valve 13 is controlled. On the other hand, when the contacts 28a and 28c and the contacts 30a and 30c of the changeover switches 28 and 30 are connected, the output signal of the vacuum gauge 29 is input to the comparator circuit 24, and this signal and the pressure setting circuit 33 are connected. The set pressure signal is compared with the second operating signal, and the opening degree of the flow rate adjustment valve 13 is controlled.
第３図はマスフローコントローラ３５を用いた
この発明の他の実施例を示すブロツク図である。
マスフローコントローラ３５は、流量制御バルブ
１３、バルブ作動部材１９、流量センサ２１およ
び第１の比較回路２３を備えている。スイツチ３
２の接点３２ａと接点３２ｂとが接続されると、
流量設定回路２５からの設定流量信号が第１の比
較回路２３に入力し、流量センサ２１からの出力
信号との偏差を検知して第１の動作信号をバルブ
作動部材に出力し、偏差量が零になるように流量
制御バルブ１３の開度が調整される。一方、スイ
ツチ３２の接点３２ａと接点３２ｃとが接続され
ると、真空計２９からの出力信号と圧力設定回路
３３からの設定圧力信号が第２の比較回路３１で
比較されて偏差が検知され、マスフローコントロ
ーラ３５の第２比較回路２３を経て第２の動作信
号がバルブ作動部材１９に出力され、偏差量が零
になるように流量制御バルブ１３の開度が調整さ
れる。 FIG. 3 is a block diagram showing another embodiment of the present invention using a mass flow controller 35. As shown in FIG.
The mass flow controller 35 includes a flow control valve 13 , a valve operating member 19 , a flow sensor 21 , and a first comparison circuit 23 . switch 3
When the contacts 32a and 32b of No. 2 are connected,
The set flow rate signal from the flow rate setting circuit 25 is input to the first comparison circuit 23, which detects the deviation from the output signal from the flow rate sensor 21 and outputs the first operating signal to the valve actuating member. The opening degree of the flow control valve 13 is adjusted so that the flow rate becomes zero. On the other hand, when the contacts 32a and 32c of the switch 32 are connected, the output signal from the vacuum gauge 29 and the set pressure signal from the pressure setting circuit 33 are compared in the second comparison circuit 31, and a deviation is detected. A second operation signal is output to the valve operating member 19 via the second comparison circuit 23 of the mass flow controller 35, and the opening degree of the flow control valve 13 is adjusted so that the amount of deviation becomes zero.
以上のようにこの発明の真空雰囲気制御装置に
よれば、真空槽へのガスの流量を制御することの
できる流量制御バルブを設け、切換えスイツチな
どを用いて流量比較信号および圧力比較信号の双
方により択一的に上記流量バルブを制御すること
により１つの流量制御バルブで流量を基準とし
て、あるいは圧力を基準として真空雰囲気を制御
することができる。よつて、真空槽へのガス導入
に用いる流量制御バルブやガス導入口を１つ設け
るだけで、圧力あるいはガス流入量のいずれを基
準としても真空雰囲気を調整することができ、装
置の簡略化が可能である。また、リークを起こす
可能性のある箇所もそれだけ減少し、真空装置の
保守管理も容易となる。 As described above, according to the vacuum atmosphere control device of the present invention, a flow rate control valve that can control the flow rate of gas to the vacuum chamber is provided, and a changeover switch or the like is used to control the gas flow rate by both the flow rate comparison signal and the pressure comparison signal. Alternatively, by controlling the flow valves, it is possible to control the vacuum atmosphere on a flow rate basis or on a pressure basis with a single flow control valve. Therefore, by simply providing one flow control valve or gas inlet for introducing gas into the vacuum chamber, the vacuum atmosphere can be adjusted based on either pressure or gas inflow rate, simplifying the equipment. It is possible. Furthermore, the number of locations where leaks may occur is reduced accordingly, and maintenance management of the vacuum equipment becomes easier.
第１図、第２図および第３図はこの発明の真空
雰囲気制御装置の実施例の構成を示すブロツク図
である。
図中、１１は真空槽、１３は流量制御バルブ、
１９はバルブ作動部材、２１は流量センサ、２３
は第１の比較回路、２４は比較回路、２５は流量
設定回路、２７は切換スイツチ、２９は真空計、
３１は第２の比較回路、３３は圧力設定回路、３
５はマスフローコントローラである。
FIGS. 1, 2, and 3 are block diagrams showing the construction of an embodiment of the vacuum atmosphere control device of the present invention. In the figure, 11 is a vacuum chamber, 13 is a flow control valve,
19 is a valve operating member, 21 is a flow rate sensor, 23
24 is a comparison circuit, 25 is a flow rate setting circuit, 27 is a changeover switch, 29 is a vacuum gauge,
31 is a second comparison circuit, 33 is a pressure setting circuit, 3
5 is a mass flow controller.
Claims (1)
を比較し偏差を検知して第１の動作信号を出力
し、真空計からの出力信号と設定圧力信号とを比
較し偏差を検知して第２の動作信号を出力する比
較回路と、 真空槽へのガス流量を調整する流量調整バルブ
と、 前記第１または第２の動作信号を受けて偏差量
が許容量以下となるように前記流量制御バルブの
開度を制御する制御機構と、 前記第１または第２の動作信号を選択的に前記
制御機構に供給する信号切換機構とを有すること
を特徴とする真空雰囲気制御装置。[Claims] 1. Compare the output signal from the flow rate sensor and the set flow rate signal to detect a deviation and output a first operation signal, and compare the output signal from the vacuum gauge and the set pressure signal to detect the deviation. a comparison circuit that detects and outputs a second operation signal; a flow rate adjustment valve that adjusts the gas flow rate to the vacuum chamber; and a flow rate adjustment valve that receives the first or second operation signal so that the deviation amount is less than an allowable amount. A vacuum atmosphere control device comprising: a control mechanism that controls the opening degree of the flow rate control valve; and a signal switching mechanism that selectively supplies the first or second operation signal to the control mechanism. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59012578A JPS60155669A (en) | 1984-01-26 | 1984-01-26 | Device for controlling vacuum atmosphere |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59012578A JPS60155669A (en) | 1984-01-26 | 1984-01-26 | Device for controlling vacuum atmosphere |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60155669A JPS60155669A (en) | 1985-08-15 |
| JPH0232352B2 true JPH0232352B2 (en) | 1990-07-19 |
Family
ID=11809235
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59012578A Granted JPS60155669A (en) | 1984-01-26 | 1984-01-26 | Device for controlling vacuum atmosphere |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60155669A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03126273U (en) * | 1990-03-28 | 1991-12-19 |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61259746A (en) * | 1985-05-15 | 1986-11-18 | Tokuda Seisakusho Ltd | Apparatus for opening and closing vacuum container |
| JPH0815540B2 (en) * | 1985-12-27 | 1996-02-21 | 株式会社日立製作所 | Processing equipment |
-
1984
- 1984-01-26 JP JP59012578A patent/JPS60155669A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03126273U (en) * | 1990-03-28 | 1991-12-19 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60155669A (en) | 1985-08-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6142163A (en) | Method and apparatus for pressure control in vacuum processors | |
| US20040204794A1 (en) | Advance pressure type flow control device | |
| EP1934043A2 (en) | Wide range pressure control using turbo pump | |
| US4856475A (en) | Rotational frequency control apparatus of internal combustion engine | |
| US4798521A (en) | System and method for regulating pressure in a container | |
| JP4417434B2 (en) | Method and apparatus for controlling the pressure of a vacuum processor | |
| JPH0232352B2 (en) | ||
| JPS6320605A (en) | Air pressure regulator | |
| JPH1011152A (en) | Vacuum exhaustion device of processor | |
| JPH0447416A (en) | Flow rate control method | |
| JP2939843B2 (en) | Main pipe pressure control device | |
| JPH03982A (en) | Vacuum chamber pressure control system | |
| JPS60156984A (en) | Automatic control device in vacuum atmosphere | |
| JPH06266446A (en) | Pressure controller for vacuum chamber | |
| JPH076962A (en) | Gas pressure control method and device | |
| JPH05341849A (en) | Fluid flow-rate controller for steam turbine power plant | |
| JPS6283928A (en) | Powder feed controller | |
| JPH04318295A (en) | Differential pressure control device | |
| KR100467539B1 (en) | Method and apparatus for pressure control in vacuum processors | |
| JPH06138954A (en) | Pressure controller | |
| JPS6062681A (en) | Pump system | |
| JP2001051723A (en) | Flow rate controller and flow rate controlling method | |
| JPS611983A (en) | Controller for degree of vacuum | |
| JPH0318674A (en) | Gas pressure controlling method and vacuum device | |
| JPH04349195A (en) | Vacuum apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |