JPH0535225B2 - - Google Patents
Info
- Publication number
- JPH0535225B2 JPH0535225B2 JP60121726A JP12172685A JPH0535225B2 JP H0535225 B2 JPH0535225 B2 JP H0535225B2 JP 60121726 A JP60121726 A JP 60121726A JP 12172685 A JP12172685 A JP 12172685A JP H0535225 B2 JPH0535225 B2 JP H0535225B2
- Authority
- JP
- Japan
- Prior art keywords
- gas
- flow rate
- flow path
- raw material
- carrier gas
- 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
- 239000007789 gas Substances 0.000 claims description 180
- 239000002994 raw material Substances 0.000 claims description 67
- 239000012159 carrier gas Substances 0.000 claims description 64
- 238000005259 measurement Methods 0.000 claims description 7
- 239000000463 material Substances 0.000 description 8
- 230000001276 controlling effect Effects 0.000 description 7
- 238000001514 detection method Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000009530 blood pressure measurement Methods 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 4
- 238000001704 evaporation Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000010408 film Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000012495 reaction gas Substances 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 229910007926 ZrCl Inorganic materials 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D11/00—Control of flow ratio
- G05D11/02—Controlling ratio of two or more flows of fluid or fluent material
- G05D11/13—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means
- G05D11/131—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means by measuring the values related to the quantity of the individual components
- G05D11/132—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means by measuring the values related to the quantity of the individual components by controlling the flow of the individual components
Description
【発明の詳細な説明】
〔発明の技術分野〕
本発明はキヤリアガスと原料ガスとの混合ガ
ス、例えばCVD装置における反応ガスの流量を
制御する装置に係り、特にキヤリアガスおよび原
料ガスの流量を個別に制御できる流量制御装置に
関する。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a device for controlling the flow rate of a mixed gas of a carrier gas and a raw material gas, such as a reaction gas in a CVD device, and particularly relates to a device for controlling the flow rate of a mixed gas of a carrier gas and a raw material gas, for example, a reaction gas in a CVD device. The present invention relates to a controllable flow rate control device.
CVD法は、原料ガスをキヤリアガスに乗せて
反応炉に導き、高温下での化学反応により試料上
に薄膜を形成する技術であり、半導体装置および
その関連装置において多用される膜形成技術の一
つである。CVD法においては液体または固体状
の原料をガス化して反応炉に供給する場合、安定
な流量制御を行なうことが重要であり、そのため
の種々の方式が考案されている。その一つとして
キヤリアガスの流量および原料加熱温度を一定に
保つことで、一定流量の蒸発ガス（キヤリアガス
と原料ガイドとの混合ガス）を得るキヤリアガス
制御方式がある。しかし、この方式では原料の経
時変化，蒸発に伴う温度変化等により、蒸発量を
一定に制御することができない。
The CVD method is a technology in which raw material gas is carried on a carrier gas and introduced into a reactor, and a thin film is formed on a sample through a chemical reaction at high temperatures.It is one of the film formation technologies often used in semiconductor devices and related equipment. It is. In the CVD method, when a liquid or solid raw material is gasified and supplied to a reactor, it is important to perform stable flow control, and various methods have been devised for this purpose. One of them is a carrier gas control method that obtains a constant flow rate of evaporated gas (mixed gas of carrier gas and raw material guide) by keeping the carrier gas flow rate and raw material heating temperature constant. However, with this method, it is not possible to control the amount of evaporation to a constant level due to changes in the raw material over time, temperature changes due to evaporation, etc.
この欠点を解消すべく、原料ガスの濃度を直接
検出し、それに基いて原料ガス流量を高精度に制
御する方式が開発されている。具体的には、恒温
槽内にキヤリアガスを導き、ガスの熱伝導率の変
化を利用したいわゆる熱動センサを用いてキヤリ
アガスの濃度を検出した後、原料を蒸発させてキ
ヤリアガスと原料ガスとの混合ガスを作り、この
混合ガスの濃度を同様に熱動センサを通して検出
する。これらの熱動センサを２辺に接続してホイ
ートストン・ブリツジ回路を構成することによ
り、キヤリアガスと混合ガスとの濃度比信号を求
め、この濃度比信号から原料ガスの流量を算出す
る。そして、この原料ガス流量を設定流量と比較
し、両者が一致するようにキヤリアガスの流量を
調整するのである。しかしながら、この方式では
次のような問題があつた。 In order to overcome this drawback, a method has been developed in which the concentration of the raw material gas is directly detected and the flow rate of the raw material gas is controlled with high precision based on the detected concentration. Specifically, a carrier gas is introduced into a thermostatic chamber, the concentration of the carrier gas is detected using a so-called thermal sensor that uses changes in the thermal conductivity of the gas, and the raw material is evaporated to mix the carrier gas and the raw material gas. A gas is produced and the concentration of this gas mixture is similarly detected through a thermal sensor. By connecting these thermal sensors on two sides to form a Wheatstone bridge circuit, a concentration ratio signal between the carrier gas and the mixed gas is obtained, and the flow rate of the source gas is calculated from this concentration ratio signal. This raw material gas flow rate is then compared with the set flow rate, and the carrier gas flow rate is adjusted so that the two match. However, this method has the following problems.
最近、CVD装置における膜形成原料としては、
低蒸気圧材料の使用が要求される傾向にある。低
蒸気圧材料は材料の高温化によつて原料ガスの多
量供給を可能とする反面、高温化によつて材料の
熱分解が生じ、また固体材料の場合は粒子の固化
が起こる。これを避けるには、材料を減圧下で蒸
発させて低温化を図ればよい。ところが、上述し
た流量制御装置は常圧下では特に問題はないが、
20Torr以下というような減圧下ではガスの熱伝
導率が圧力の影響を受ける関係で、上記２つの熱
動センサ間に存在する原料タンク，配管等の圧力
損失により生じる圧力差によつて濃度測定値、す
なわち原料ガスの流量測定値に誤差が生じ、高精
度な流量制御が困難となる。 Recently, as a film forming raw material in CVD equipment,
The trend is to require the use of low vapor pressure materials. Low vapor pressure materials enable the supply of a large amount of raw material gas by increasing the temperature of the material, but the increase in temperature causes thermal decomposition of the material, and in the case of solid materials, solidification of particles occurs. To avoid this, the material can be evaporated under reduced pressure to lower the temperature. However, although there is no particular problem with the above-mentioned flow control device under normal pressure,
Under reduced pressure, such as 20 Torr or less, the thermal conductivity of gas is affected by pressure, so the concentration measurement value is determined by the pressure difference caused by pressure loss in the raw material tank, piping, etc. that exists between the two thermal sensors. That is, an error occurs in the measured flow rate of the raw material gas, making it difficult to control the flow rate with high precision.
また、従来の流量制御装置では原料ガスの流量
は一定に保たれるが、キヤリアガスの流量が制御
により変動するため、反応炉内に送り込む混合ガ
スの原料ガス分圧を一定化できず、反応の再現性
が悪い。 In addition, with conventional flow rate control devices, the flow rate of the raw material gas is kept constant, but because the flow rate of the carrier gas fluctuates due to the control, the raw gas partial pressure of the mixed gas fed into the reactor cannot be kept constant, and the reaction Poor reproducibility.
さらに、キヤリアガスの流量を制御することで
混合ガスの流量を制御しているため、キヤリアガ
スの流量が減少制御された場合に混合ガス中の原
料ガス飽和度が上昇し過ぎることがあり、反応炉
内への配管内での原料ガスの再液化あるいは再固
化が起こる危険性がある。このような場合は当
然、原料ガスの安定な供給はできなくなる。 Furthermore, since the flow rate of the mixed gas is controlled by controlling the flow rate of the carrier gas, when the flow rate of the carrier gas is controlled to decrease, the saturation level of the raw material gas in the mixed gas may rise too much. There is a risk of re-liquefaction or re-solidification of the feed gas in the piping. Naturally, in such a case, it becomes impossible to stably supply the raw material gas.
本発明の目的は、キヤリアガスと原料ガスとの
混合ガスが供給される系が減圧下にある場合でも
高精度な流量制御が可能で、また混合ガス中にお
ける原料ガス分圧を一定に制御することができ、
さらに原料ガスの再液化，再固化を防止できる流
量制御装置を提供することにある。
An object of the present invention is to enable highly accurate flow control even when a system to which a mixed gas of carrier gas and source gas is supplied is under reduced pressure, and to control the partial pressure of the source gas in the mixed gas to a constant level. is possible,
Another object of the present invention is to provide a flow rate control device that can prevent reliquefaction and resolidification of raw material gas.
本発明においては上記目的を達成するため、キ
ヤリアガス流路および混合ガス流路とは別にキヤ
リアガスと同種の参照ガスの流路が設けられ、こ
の参照ガスが混合ガスと共に被ガス供給系に供給
される。また、キヤリアガスおよび参照ガスの各
流路にそれぞれ第１および第２の流量調整手段が
設けられる。そして、ガスの熱伝導率の変化を利
用して混合ガスおよび参照ガスの濃度を測定する
熱動センサが混合ガスおよび参照ガスのそれぞれ
の流路に設けられ、これらの熱動センサを介して
混合ガス中の原料ガスの濃度が測定される。この
濃度測定値と実際のキヤリアガス流量および原料
ガス設定流量に基いて第１の流量調整手段により
原料タンクへのキヤリアガスの流量が制御される
ことにより、原料ガスの流量が一定化されるとと
もに、キヤリアガス設定流量に基いて第２の流量
調整手段により参照ガスの流量が制御されること
により、キヤリアガスの総流量が一定化される。
このようにして、原料ガスおよびキヤリアガスの
流量が個別に制御される。
In order to achieve the above object, in the present invention, a flow path for a reference gas of the same type as the carrier gas is provided separately from the carrier gas flow path and the mixed gas flow path, and this reference gas is supplied to the gas supply system together with the mixed gas. . Furthermore, first and second flow rate adjusting means are provided in each of the carrier gas and reference gas flow paths, respectively. Then, thermal sensors that measure the concentrations of the mixed gas and reference gas using changes in the thermal conductivity of the gas are installed in the flow paths of the mixed gas and the reference gas, respectively, and the mixture is measured via these thermal sensors. The concentration of source gas in the gas is measured. The flow rate of the carrier gas to the raw material tank is controlled by the first flow rate adjustment means based on this concentration measurement value, the actual carrier gas flow rate, and the set flow rate of the raw material gas, so that the flow rate of the raw material gas is constant, and the carrier gas By controlling the flow rate of the reference gas by the second flow rate adjustment means based on the set flow rate, the total flow rate of the carrier gas is made constant.
In this way, the flow rates of the source gas and carrier gas are individually controlled.
本発明によれば、混合ガス流路および参照ガス
流路をそれぞれ通過するガスの熱伝導率の変化か
ら混合ガス中の原料ガスの濃度を測定し、それに
基いてキヤリアガス流路から原料タンクへ供給さ
れるキヤリアガスの流量を制御するため、原料ガ
スの流量制御を高精度に行なうことができる。す
なわち、混合ガス流路および参照ガス流路は共に
被ガス供給系に接続されており、被ガス供給系が
減圧下にある場合でもほぼ同圧に保持されること
から、圧力差による濃度測定誤差はほとんど生じ
ない。
According to the present invention, the concentration of the raw material gas in the mixed gas is measured from the change in thermal conductivity of the gas passing through the mixed gas flow path and the reference gas flow path, and the raw material gas is supplied from the carrier gas flow path to the raw material tank based on the measurement. Since the flow rate of the carrier gas is controlled, the flow rate of the raw material gas can be controlled with high precision. In other words, both the mixed gas flow path and the reference gas flow path are connected to the target gas supply system, and are maintained at approximately the same pressure even when the target gas supply system is under reduced pressure, so concentration measurement errors due to pressure differences may occur. rarely occurs.
また、原料タンクへのキヤリアガスの流量が制
御により変化しても、被ガス供給系に供給される
キヤリアガスの総流量は原料タンクへのキヤリア
ガスと、それと同種である参照ガスとの和の流量
であるため、参照ガスの流量制御によりキヤリア
ガス総流量が一定に保たれる。従つて、被ガス供
給系に送出される混合ガス中の原料ガス分圧を一
定化することが可能となり、被ガス供給系が反応
炉の場合、反応の再現性が向上する。 Furthermore, even if the flow rate of the carrier gas to the raw material tank is changed by control, the total flow rate of the carrier gas supplied to the gas supply system is the sum of the flow rate of the carrier gas to the raw material tank and the reference gas of the same type. Therefore, the total flow rate of the carrier gas is kept constant by controlling the flow rate of the reference gas. Therefore, the partial pressure of the raw material gas in the mixed gas sent to the gas supply system can be made constant, and when the gas supply system is a reactor, the reproducibility of the reaction is improved.
さらに、被ガス供給系に送出される混合ガス中
に、原料タンクへのキヤリアガスとは別の流路か
らの参照ガスもキヤリアガスとして常に含まれる
ため、該混合ガス中の原料ガス飽和度を一定値以
下に抑制することができ、原料ガスの再液化，再
固化が防止される。 Furthermore, the reference gas from a flow path different from the carrier gas to the raw material tank is always included as a carrier gas in the mixed gas sent to the gas supply system, so the saturation level of the raw material gas in the mixed gas is kept at a constant value. Therefore, reliquefaction and resolidification of the raw material gas can be prevented.
第１図は本発明の一実施例に係る流量制御装置
の構成をCVD装置に適用した場合について示し
たものである。
FIG. 1 shows a case where the configuration of a flow rate control device according to an embodiment of the present invention is applied to a CVD device.
図に示すように、キヤリアガス供給源１からの
Ar，He等のガスは二分岐され、一方はキヤリア
ガス流路２に、また他方は参照ガス流路３に送出
される。キヤリアガス流路２および参照ガス流路
３には、それぞれ第１，第２の流量調整器４，５
が設けられている。第１の流量調整器４は流量セ
ンサ４ａ，比較器４ｂおよびバルブ４ｃにより構
成され、また第２の流量調整器５も同様に流量セ
ンサ５ａ，比較器５ｂおよびバルブ５ｃにより構
成されている。流量調整器４，５を通過したキヤ
リアガスおよび参照ガスは、恒温槽６内に導かれ
る。 As shown in the figure, from carrier gas supply source 1,
Gases such as Ar and He are branched into two, one being sent to the carrier gas flow path 2 and the other to the reference gas flow path 3. The carrier gas flow path 2 and the reference gas flow path 3 are provided with first and second flow rate regulators 4 and 5, respectively.
is provided. The first flow rate regulator 4 is composed of a flow rate sensor 4a, a comparator 4b, and a valve 4c, and the second flow rate regulator 5 is similarly composed of a flow rate sensor 5a, a comparator 5b, and a valve 5c. The carrier gas and reference gas that have passed through the flow rate regulators 4 and 5 are guided into a constant temperature chamber 6.
恒温槽６は内部温度が例えば20〜200℃の範囲
内の任意の温度に設定可能に構成されている。こ
の恒温槽６内には、例えば高純度のWCl6，
ZrCl4，MoCl5等の低蒸気圧材料からなる原料７
を収容した原料タンク８が設置されており、恒温
槽６内に導入されたガスのうち、キヤリアガスが
この原料タンク８に導かれる。これにより原料タ
ンク８から原料ガスとキヤリアガスとの混合ガス
が蒸発され、この混合ガスが混合ガス流路９およ
び圧力測定用流路１０に導かれる。 The constant temperature bath 6 is configured such that its internal temperature can be set to any temperature within the range of, for example, 20 to 200°C. This thermostatic chamber 6 contains, for example, high-purity WCl 6 ,
Raw material 7 made of low vapor pressure materials such as ZrCl 4 and MoCl 5
A raw material tank 8 containing . As a result, the mixed gas of the raw material gas and the carrier gas is evaporated from the raw material tank 8, and this mixed gas is guided to the mixed gas flow path 9 and the pressure measurement flow path 10.
恒温槽６内における混合ガス流路９および参照
ガス流路３には、それぞれ熱動センサ１１，１２
が挿入されている。熱動センサ１１，１２は具体
的にはフイラメントで構成され、混合ガスおよび
参照ガスの濃度をそれぞれのガスの熱伝導率の違
いを利用して測定し、最終的に混合ガス中の原料
ガスの濃度を測定するためのものである。なお、
熱動センサ１１，１２においてフイラメントを収
納するセルは、圧力の影響をより受けにくい、つ
まりガスの流量に影響されない拡散型であること
が望ましい。また、濃度測定に当たり熱動センサ
１１，１２の温度特性の影響を無視できるよう
に、キヤリアガス流路２および参照ガス流路３の
恒温槽６内での長さをできるだけ長くとることに
より、それぞれのガスの温度を等しくするのが望
ましい。 Thermal sensors 11 and 12 are installed in the mixed gas flow path 9 and the reference gas flow path 3 in the thermostatic chamber 6, respectively.
is inserted. Thermal sensors 11 and 12 are specifically constructed of filaments, and measure the concentrations of the mixed gas and reference gas by utilizing the difference in thermal conductivity of each gas, and ultimately measure the concentration of the raw material gas in the mixed gas. It is used to measure concentration. In addition,
In the thermal sensors 11 and 12, the cells that house the filaments are desirably of a diffusion type that is less susceptible to the influence of pressure, that is, unaffected by the flow rate of gas. Furthermore, in order to ignore the influence of the temperature characteristics of the thermal sensors 11 and 12 during concentration measurement, the lengths of the carrier gas flow path 2 and the reference gas flow path 3 in the thermostatic chamber 6 are made as long as possible. It is desirable to equalize the gas temperatures.
熱動センサ１１，１２を通過した混合ガスおよ
び参照ガスは合流用流路１３で合流された後、圧
力調整用バルブ１４を経て恒温槽６外へ送出さ
れ、反応炉１５内に導入される。反応炉１５はト
ラツプ１６を介して真空ポンプ１７に接続されて
おり、これにより20Torr程度以下の圧力に減圧
される。また、反応炉１５にはさらに還元ガス流
量センサ１８を介してバルブ１９が接続される。 The mixed gas and reference gas that have passed through the thermal sensors 11 and 12 are combined in a merging channel 13, then sent out of the constant temperature chamber 6 through a pressure adjustment valve 14 and introduced into the reactor 15. The reactor 15 is connected to a vacuum pump 17 via a trap 16, which reduces the pressure to about 20 Torr or less. Further, a valve 19 is further connected to the reaction furnace 15 via a reducing gas flow rate sensor 18 .
一方、圧力測定用流路１０に導かれた混合ガス
は恒温槽６外に送出され、圧力センサ２０でその
圧力が検出される。圧力センサ２０の出力は演算
回路２１に入力され、圧力設定器２２で設定され
た圧力と、圧力センサ２０で検出された圧力とが
等しくなるように圧力調整用バルブ１４が制御さ
れる。 On the other hand, the mixed gas guided to the pressure measurement channel 10 is sent out of the thermostatic chamber 6, and the pressure thereof is detected by the pressure sensor 20. The output of the pressure sensor 20 is input to an arithmetic circuit 21, and the pressure adjustment valve 14 is controlled so that the pressure set by the pressure setting device 22 and the pressure detected by the pressure sensor 20 are equal.
熱動センサ１１，１２は濃度測定器２３に接続
されている。熱動センサ１１，１２および濃度測
定器２３の部分の詳細な構成を第２図に示す。熱
動センサ（フイラメント）１１，１２と固定抵抗
３１，３２とでホイートストン・ブリツジ回路が
構成され、このブリツジ回路に直流電源３３から
電圧が印加される。熱動センサ１１，１２は電源
３３からの電流により発熱し、第１図の混合ガス
流路９および参照ガス流路３をそれぞれ通過する
混合ガスおよび参照ガスによつて冷却されるが、
そのときの熱動センサ１１，１２の温度はそれぞ
れのガスの熱伝導率、つまりガスの濃度によつて
異なり、結局その抵抗値に差が生じる。従つて、
この抵抗値の差によりブリツジ回路の出力に生じ
る不平衡電圧を増幅器３４を介して取出すことに
よつて、混合ガス中の原料ガスの濃度を表わす濃
度比信号を得ることができる。 Thermal sensors 11 and 12 are connected to a concentration measuring device 23. The detailed structure of the thermal sensors 11, 12 and the concentration measuring device 23 is shown in FIG. Thermal sensors (filaments) 11 and 12 and fixed resistors 31 and 32 constitute a Wheatstone bridge circuit, and a voltage is applied from a DC power supply 33 to this bridge circuit. The thermal sensors 11 and 12 generate heat due to the current from the power source 33, and are cooled by the mixed gas and reference gas passing through the mixed gas flow path 9 and the reference gas flow path 3 in FIG. 1, respectively.
The temperatures of the thermal sensors 11 and 12 at this time differ depending on the thermal conductivity of each gas, that is, the concentration of the gases, resulting in a difference in their resistance values. Therefore,
By extracting the unbalanced voltage generated at the output of the bridge circuit due to the difference in resistance values through the amplifier 34, a concentration ratio signal representing the concentration of the raw material gas in the mixed gas can be obtained.
ここで、熱動センサ１１，１２が設置された混
合ガス流路９および参照ガス流路３は合流流路１
３で結合され、圧力調整用バルブ１４，反応炉１
５およびトラツプ１６を経て同圧に保持されてい
るため、減圧下にありながら圧力差による濃度検
出誤差はほとんど生じない。すなわち、濃度検出
のための２つの熱動センサを原料タンクへ至るキ
ヤリア流路、および原料タンクからの混合ガス流
路にそれぞれ配置した従来装置では、混合ガス流
路が減圧下にある場合、両流路間に生じる圧力差
によりガスの分子密度が変わり、ガスの熱伝導率
が影響を受ける。このため、第３図に破線で示す
ように減圧下ではブリツジ回路の出力オフセツト
（零点シフト）が非常に大きくなり、濃度検出誤
差が増大する。 Here, the mixed gas flow path 9 and the reference gas flow path 3 in which the thermal sensors 11 and 12 are installed are connected to the confluence flow path 1.
3, pressure regulating valve 14, reactor 1
Since the pressure is maintained at the same level through the traps 5 and 16, almost no concentration detection errors occur due to pressure differences even though the pressure is reduced. In other words, in the conventional device in which two thermal sensors for concentration detection are placed in the carrier flow path leading to the raw material tank and the mixed gas flow path from the raw material tank, when the mixed gas flow path is under reduced pressure, both The pressure difference created between the flow paths changes the molecular density of the gas, which affects the thermal conductivity of the gas. Therefore, as shown by the broken line in FIG. 3, the output offset (zero point shift) of the bridge circuit becomes extremely large under reduced pressure, and the concentration detection error increases.
これに対し、本発明においては熱動センサ１
１，１２の圧力差がないため、第３図に実線で示
すように減圧下でもブリツジ回路出力のオフセツ
トは極めて少なく、高い濃度検出精度が得られ
る。なお、オフセツトが＋，−側に幅を持つてい
るのは、熱動センサ１１，１２の温度特性の違い
に起因するものであり、温度特性が同じであれば
オフセツトはほとんど発生しない。 In contrast, in the present invention, the thermal sensor 1
Since there is no pressure difference between 1 and 12, the offset of the bridge circuit output is extremely small even under reduced pressure, as shown by the solid line in FIG. 3, and high concentration detection accuracy can be obtained. The reason why the offset has a width on the + and - sides is due to the difference in the temperature characteristics of the thermal sensors 11 and 12, and if the temperature characteristics are the same, almost no offset will occur.
こうして熱動センサ１１，１２および濃度測定
器２３を通して得られた濃度比信号は、第１図に
示すように演算回路２４に入力され、この濃度比
信号と第１の流量調整器４における流量センサ４
ａで得られたキヤリアガスの流量信号に基いて、
混合ガス中の原料ガスの流量が求められる。この
演算回路２４からの原料ガス流量信号と、原料ガ
ス流量設定器２５からの原料ガス設定流量信号と
が第１の流量調整器４における比較器４ｂに入力
されて両信号の差信号が求められ、この比較器４
ｂの出力によつてバルブ４ｃが調整され、原料ガ
スの流量と原料ガス設定流量との差流量が零とな
るように、キヤリアガス流路２を通過するキヤリ
アガスの流量が制御される。 The concentration ratio signal thus obtained through the thermal sensors 11, 12 and the concentration measuring device 23 is input to the arithmetic circuit 24 as shown in FIG. 4
Based on the carrier gas flow rate signal obtained in step a,
The flow rate of the raw material gas in the mixed gas is determined. The source gas flow rate signal from the calculation circuit 24 and the source gas set flow rate signal from the source gas flow rate setting device 25 are input to the comparator 4b in the first flow rate regulator 4, and a difference signal between the two signals is determined. , this comparator 4
The valve 4c is adjusted by the output of step b, and the flow rate of the carrier gas passing through the carrier gas flow path 2 is controlled so that the difference in flow rate between the flow rate of the raw material gas and the set flow rate of the raw material gas becomes zero.
このようにして減圧下においても、反応炉１５
への原料ガスの安定な供給を行なうことができ
る。換言すれば、原料７を減圧下において蒸発さ
せることができるので、原料７として低蒸気圧材
料を使用することが可能となる。その結果、低蒸
気圧材料がMoCl5の場合を例にとると、50Torr
の減圧下では、常圧（大気圧）下で蒸発させる場
合に比べ10倍の蒸発量（流量）が得られ、さらに
10Torrの減圧下では40倍以上という極めて多量
の原料ガスの安定な供給が可能となる。一方、第
１の流量調整器４における流量センサ４ａから出
力されるキヤリア流量信号と、キヤリアガス総流
量設定器２６からのキヤリアガスの設定総流量信
号との差が減算器２７で求められ、その差流量信
号が第２の流量調整器５における比較器５ｂに入
力され、流量センサ５ａからの参照ガス流量信号
と比較される。この比較器５ｂの出力によつてバ
ルブ５ｃが調整され、合流流路１３へ送出される
ガス中のキヤリアガスの総流路がキヤリアガス設
定総流量に一致するように参照ガスの流量が制御
される。すなわち、参照ガスはキヤリアガスと同
種のガスであるため、この参照ガス流量を制御す
ることで、合流部材１３を通して反応炉１５に供
給されるガス中のキヤリアガスの成分の総流量が
一定に維持される。 In this way, even under reduced pressure, the reactor 15
It is possible to stably supply raw material gas to. In other words, since the raw material 7 can be evaporated under reduced pressure, it is possible to use a low vapor pressure material as the raw material 7. As a result, if the low vapor pressure material is MoCl 5 , for example, 50Torr
Under reduced pressure, the amount of evaporation (flow rate) is 10 times that of evaporation under normal pressure (atmospheric pressure), and
Under a reduced pressure of 10 Torr, it is possible to stably supply an extremely large amount of raw material gas, which is more than 40 times larger. On the other hand, the difference between the carrier flow rate signal output from the flow rate sensor 4a in the first flow rate regulator 4 and the carrier gas set total flow rate signal from the carrier gas total flow rate setting device 26 is obtained by the subtractor 27, and the difference flow rate is The signal is input to the comparator 5b in the second flow regulator 5 and compared with the reference gas flow signal from the flow sensor 5a. The valve 5c is adjusted by the output of the comparator 5b, and the flow rate of the reference gas is controlled so that the total flow path of the carrier gas in the gas sent to the merging flow path 13 matches the set total flow rate of the carrier gas. That is, since the reference gas is the same type of gas as the carrier gas, by controlling the flow rate of this reference gas, the total flow rate of the carrier gas components in the gas supplied to the reactor 15 through the merging member 13 is maintained constant. .
このようにキヤリアガスの総流量も安定化され
る結果、反応炉１５へ送り込まれる混合ガスの原
料ガス分圧を一定にすることができ、反応の再現
性が向上する。 As a result of stabilizing the total flow rate of the carrier gas in this way, the raw material gas partial pressure of the mixed gas sent to the reactor 15 can be kept constant, and the reproducibility of the reaction is improved.
また、原料ガスの流量制御の過程でキヤリアガ
ス流路２を通過するキヤリアガスの流量が大きく
減少しても、反応炉１５に送り込まれる混合ガス
中に参照ガス流路３の経路でキヤリアガスと同じ
ガスが合流されることにより、この混合ガスの原
料ガス飽和度が低下することはなく、合流流路１
３等の配管内での原料ガスの再液化，再固化とい
つた問題は生じない。 In addition, even if the flow rate of the carrier gas passing through the carrier gas flow path 2 is significantly reduced in the process of controlling the flow rate of the raw material gas, the same gas as the carrier gas may be present in the mixed gas sent to the reactor 15 in the path of the reference gas flow path 3. By merging, the raw material gas saturation of this mixed gas does not decrease, and the merging flow path 1
Problems such as reliquefaction and resolidification of the raw material gas in the 3rd grade piping do not occur.
また、上記実施例によれば原料タンク８が恒温
槽６内に配置されており、しかも圧力調整用バル
ブ１４，圧力測定用流路１０，圧力センサ２０，
演算回路２１および圧力設定器２２を用いて原料
タンク８内の圧力も一定に制御しているため、原
料ガス流量をより一層安定化することが可能であ
る。 Further, according to the above embodiment, the raw material tank 8 is arranged in the thermostatic chamber 6, and the pressure adjustment valve 14, the pressure measurement channel 10, the pressure sensor 20,
Since the pressure inside the raw material tank 8 is also controlled to be constant using the arithmetic circuit 21 and the pressure setting device 22, it is possible to further stabilize the raw material gas flow rate.
なお、本発明は上記実施例に限定されるもので
はなく、例えば第２図におけるブリツジ回路内の
固定抵抗３１，３２を熱動センサ（フイラメン
ト）に置換え、それぞれ混合ガス流路９，参照ガ
ス流路３に挿入してもよい。このようにすると、
減圧によるフイラメントの温度上昇に伴う濃度検
出感度の変動を抑制でき、さらに高精度の濃度検
出が可能となる。また、フイラメントの温度を検
知し、その結果をブリツジ回路出力にフイードバ
ツクすることにより、いわゆる定温度型ブリツジ
回路を構成することも、より高精度の濃度検出を
行なう上で有効である。 Note that the present invention is not limited to the above-mentioned embodiment, and for example, the fixed resistors 31 and 32 in the bridge circuit in FIG. 2 are replaced with thermal sensors (filaments), and the mixed gas flow path 9 and the reference gas flow It may be inserted into path 3. In this way,
Fluctuations in concentration detection sensitivity caused by a rise in filament temperature due to reduced pressure can be suppressed, making it possible to detect concentration with even higher accuracy. Furthermore, it is also effective to configure a so-called constant temperature type bridge circuit by detecting the temperature of the filament and feeding the result back to the bridge circuit output for more accurate concentration detection.
さらに、第１図では混合ガス流路９および参照
ガス流路３が合流流路１３で１本の流路となり、
両ガスが合流されてから反応炉１５に導入されて
いるが、それぞれの流路９，３を個別に反応炉１
５に接続し、両ガスを反応炉１５内で混ぜるとい
う構成にしても同様の効果が得られる。 Furthermore, in FIG. 1, the mixed gas flow path 9 and the reference gas flow path 3 become one flow path at the confluence flow path 13,
Although both gases are introduced into the reactor 15 after being combined, each of the flow paths 9 and 3 is separately connected to the reactor 1.
Similar effects can also be obtained by connecting the reactor 15 to the reactor 15 and mixing both gases in the reactor 15.
また、本発明はCVD装置に限定されるもので
はなく、キヤリアガスと原料ガスとの混合ガスを
用いて減圧下で膜形成を行なう装置一般に適用す
ることができる。その他、本発明は要旨を逸脱し
ない範囲で種々変形して実施することが可能であ
る。 Furthermore, the present invention is not limited to CVD apparatuses, but can be applied to general apparatuses that perform film formation under reduced pressure using a mixed gas of carrier gas and raw material gas. In addition, the present invention can be implemented with various modifications without departing from the scope.
第１図は本発明の一実施例に係る流量制御装置
の構成を説明するための図、第２図は第１図にお
ける熱動センサおよび濃度測定器の部分を詳細に
示す図、第３図は従来装置および本発明装置にお
けるガス濃度測定用ブリツジ回路の出力オフセツ
トのガス圧力依存性を示す図である。
１……キヤリアガス供給源、２……キヤリアガ
ス流路、３……参照ガス流路、４，５……第１，
第２の流量調整器、６……恒温槽、７……原料、
８……原料タンク、９……混合ガス流路、１０…
…圧力測定用流路、１１，１２……熱動センサ、
１３……合流流路、１４……圧力調整用バルブ、
１５……反応炉（被ガス供給系）、１６……トラ
ツプ、１７……真空ポンプ、１８……還元ガス流
量センサ、１９……バルブ、２０……圧力セン
サ、２１……演算回路、２２……圧力設定器、２
３……濃度測定器、２４……原料ガス流量演算回
路、２５……原料ガス流量設定器、２６……キヤ
リアガス総流量設定器、２７……減算器、３１，
３２……固定抵抗、３３……直流電源、３４……
増幅器。
FIG. 1 is a diagram for explaining the configuration of a flow rate control device according to an embodiment of the present invention, FIG. 2 is a diagram showing details of the thermal sensor and concentration measuring device in FIG. 1, and FIG. 1 is a diagram showing the gas pressure dependence of the output offset of the bridge circuit for gas concentration measurement in the conventional device and the device of the present invention. DESCRIPTION OF SYMBOLS 1... Carrier gas supply source, 2... Carrier gas flow path, 3... Reference gas flow path, 4, 5... First,
Second flow rate regulator, 6... constant temperature bath, 7... raw material,
8... Raw material tank, 9... Mixed gas flow path, 10...
... Pressure measurement channel, 11, 12 ... Thermal sensor,
13... Merging channel, 14... Pressure adjustment valve,
15... Reactor (gas supply system), 16... Trap, 17... Vacuum pump, 18... Reducing gas flow rate sensor, 19... Valve, 20... Pressure sensor, 21... Arithmetic circuit, 22... ...Pressure setting device, 2
3... Concentration measuring device, 24... Raw material gas flow rate calculation circuit, 25... Raw material gas flow rate setting device, 26... Carrier gas total flow rate setting device, 27... Subtractor, 31,
32...Fixed resistance, 33...DC power supply, 34...
amplifier.
Claims (1)
ス流路と、前記原料タンクから蒸発されるキヤリ
アガスと原料ガスとの混合ガスを送出する混合ガ
ス流路と、前記キヤリアガスと同種の参照ガスを
送出する参照ガス流路と、この参照ガスを前記混
合ガスと共に被ガス供給系に送出する手段と、前
記キヤリアガス流路に設けられた第１の流量調整
手段と、前記参照ガス流路に設けられた第２の流
量調整手段と、前記混合ガス流路および前記参照
ガス流路にそれぞれ挿入され、ガスの熱伝導率の
変化を利用して混合ガスおよび参照ガスの濃度を
測定する熱動センサと、これらの熱動センサを介
して前記混合ガス中の原料ガスの濃度を測定する
手段と、この濃度測定値と前記流量キヤリアガス
流路を通過するキヤリアガス流量および原料ガス
設定流量に基いて前記第１の流量調整手段を制御
する手段と、前記キヤリアガス流路を通過するキ
ヤリアガスの流量とキヤリアガス設定総流量に基
いて前記第２の流量調整手段を制御する手段とを
備えたことを特徴とする流量制御装置。 ２ 前記原料タンクが恒温槽内に設置されている
ことを特徴とする特許請求の範囲第１項記載の流
量制御装置。 ３ 混合ガスおよび参照ガスが前記混合ガス流路
および参照ガス流路を通過した後、合流されてか
ら前記被ガス供給系に供給されることを特徴とす
る特許請求の範囲第１項記載の流量制御装置。 ４ 前記混合ガスおよび参照ガスが前記混合ガス
流路および参照ガス流路から前記被ガス供給系に
個別に供給されることを特徴とする特許請求の範
囲第１項記載の流量制御装置。[Scope of Claims] 1. A carrier gas flow path that guides a carrier gas to a raw material tank, a mixed gas flow path that delivers a mixed gas of carrier gas and raw material gas evaporated from the raw material tank, and a reference gas of the same type as the carrier gas. a reference gas flow path to send out, a means for sending out the reference gas together with the mixed gas to the gas supply system, a first flow rate adjustment means provided in the carrier gas flow path, and a first flow rate adjustment means provided in the reference gas flow path. a second flow rate adjustment means; and a thermal sensor inserted into the mixed gas flow path and the reference gas flow path to measure the concentrations of the mixed gas and the reference gas by utilizing changes in the thermal conductivity of the gas. , a means for measuring the concentration of the raw material gas in the mixed gas through these thermal sensors, and a means for measuring the concentration of the raw material gas in the mixed gas based on this concentration measurement value, a carrier gas flow rate passing through the flow rate carrier gas flow path, and a set raw material gas flow rate. Flow rate control characterized by comprising means for controlling the second flow rate adjusting means, and means for controlling the second flow rate adjusting means based on the flow rate of the carrier gas passing through the carrier gas flow path and the set total flow rate of the carrier gas. Device. 2. The flow rate control device according to claim 1, wherein the raw material tank is installed in a constant temperature bath. 3. The flow rate according to claim 1, wherein the mixed gas and the reference gas pass through the mixed gas flow path and the reference gas flow path, are combined, and then are supplied to the gas supply system. Control device. 4. The flow rate control device according to claim 1, wherein the mixed gas and the reference gas are individually supplied to the gas supply system from the mixed gas flow path and the reference gas flow path.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60121726A JPS61279678A (en) | 1985-06-05 | 1985-06-05 | Control device for flow rate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60121726A JPS61279678A (en) | 1985-06-05 | 1985-06-05 | Control device for flow rate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61279678A JPS61279678A (en) | 1986-12-10 |
| JPH0535225B2 true JPH0535225B2 (en) | 1993-05-26 |
Family
ID=14818356
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60121726A Granted JPS61279678A (en) | 1985-06-05 | 1985-06-05 | Control device for flow rate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61279678A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101578220B1 (en) * | 2008-10-31 | 2015-12-16 | 가부시키가이샤 호리바 세이샤쿠쇼 | material gas concentration control system |
| JP5145193B2 (en) * | 2008-10-31 | 2013-02-13 | 株式会社堀場製作所 | Material gas concentration control system |
| JP5281363B2 (en) * | 2008-10-31 | 2013-09-04 | 株式会社堀場製作所 | Material gas concentration control system |
| JP5281364B2 (en) * | 2008-10-31 | 2013-09-04 | 株式会社堀場製作所 | Material gas concentration control system |
| WO2010106410A1 (en) * | 2009-03-16 | 2010-09-23 | Applied Materials, Inc. | Evaporator, coating installation, and method for use thereof |
| JP5690498B2 (en) * | 2009-03-27 | 2015-03-25 | ローム・アンド・ハース・エレクトロニック・マテリアルズ，エル．エル．シー． | Method for depositing a film on a substrate and apparatus for delivering a vaporized precursor compound |
| JP5895712B2 (en) * | 2012-05-31 | 2016-03-30 | 東京エレクトロン株式会社 | Source gas supply apparatus, film forming apparatus, source gas supply method, and storage medium |
| US9243325B2 (en) * | 2012-07-18 | 2016-01-26 | Rohm And Haas Electronic Materials Llc | Vapor delivery device, methods of manufacture and methods of use thereof |
| JP6026875B2 (en) * | 2012-12-03 | 2016-11-16 | 日本エア・リキード株式会社 | Vaporization monitoring system and monitoring method for solid materials |
| JP2016040402A (en) * | 2014-08-12 | 2016-03-24 | 東京エレクトロン株式会社 | Raw material gas supply device |
-
1985
- 1985-06-05 JP JP60121726A patent/JPS61279678A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61279678A (en) | 1986-12-10 |
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|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |