DE10137673A1 - Device for supplying gas mixtures to a CVD reactor - Google Patents

Abstract

The invention relates to a device comprising a supply line branch (Z1) for a gas mixture consisting of an atomized medium (M1) and a carrier gas (T) to a CVD reactor (R). The supply line branch (Z1) comprises a supply line for the liquid medium (M1), a supply line for the carrier gas (T) and a processing unit which is fed by the supply lines and is used to convert the liquid medium (M1) into a gaseous state using an injector valve (EV1) and to mix the medium (M1) with the carrier gas (T). The supply lines are respectively provided with a through flow control unit (DS11, DS12)

Description

The invention relates to a device by means of which a CVD reactor gas mixtures with contained CVD media can be supplied.

In the manufacture of semiconductor devices are using CVD (Chemical Vapor Deposition) systems apply thin layers Generated substrates. This is done in a CVD reactor by controlled separation of CVD media from the Gas phase.

The CVD media are usually initially in liquid form before and must therefore before the gas phase separation in the Gas phase are transferred. For transferring liquid CVD Media in the gas phase are two common processes Available. In a first method, a carrier gas is passed through a container pumped with the liquid CVD medium is filled. Part of the CVD Medium into the gas phase and mixes with the Carrier gas atmosphere. A second method is based on the Atomization of the liquid CVD medium. To do this, the liquid CVD medium by means of an injection valve in one with the Small chamber enriched with carrier gas sprayed so that also a gaseous state of the CVD medium and one Mixing with the carrier gas can be achieved. As carrier gases are chemically inert gases such. B. helium used. This prevents undesirable reactions of the carrier gas with the CVD medium excluded.

In the PCT patent application WO 00/15881 there is a CVD system described on the principle of liquid evaporation CVD media based. There is a liquid CVD Medium in a container. The container has a feed line for a carrier gas, which is in the container with an adjustable River is initiated. When flowing through the Carrier gas through the filled with the liquid CVD medium The CVD medium becomes container by evaporation into the gas phase transferred and together with the carrier gas via feed lines into a CVD reactor in which a controlled Separation of the CVD medium from the gas phase on a Substrate surface takes place.

A disadvantage of previous CVD systems is that the gaseous CVD media partly already in the supply lines to the CVD Reactor and if necessary on the injection valves condense. Deposits caused in the Supply lines cause reduced and undefined Cross-sectional areas of the supply lines, which ensures a controlled supply the gas mixtures to the CVD reactor is made considerably more difficult. Ultimately, it can even lead to a complete occlusion of the Leads come. Deposits on the injection valves lead to because of the high reactivity of the CVD media Malfunctions or failure of the injection valves. by virtue of Degradations of this type are frequently required for the injection valves be replaced. Otherwise there would be too the injection valves remain in the CVD system for a long time Danger of being impaired in their function Injectors CVD media in liquid form in the CVD reactor would get and heavily pollute it.

The object of the invention is therefore a device for a To create a CVD system and a corresponding process indicate the reduced deposits of CVD media in the feed lines to the CVD reactor and optionally the injection valves are effected. It is a particular one further object of the invention that one undesirable Prevent mixing of the CVD media.

The problem underlying the invention is solved by the features of claims 1, 10, 18 and 22. Advantageous further developments and refinements are specified in the subclaims.

An inventive device for supplying gases a CvD reactor has at least one feed branch, through which a gas mixture is fed to the CVD reactor. The gas mixture is atomized by a liquid CVD Medium generated in a carrier gas. The at least one Feed line includes a first feed line for the liquid CVD medium, a second supply line for the carrier gas and one Conditioning unit. The processing unit is used for Transfer of the liquid CVD medium using a Injector in the gas phase and for mixing the CVD medium with the carrier gas. For this, the processing unit on the input side through the first supply line with the liquid CVD Medium and through the second feed line with the carrier gas provided. An essential idea of the invention is that the first lead is a first Flow control unit and the second feed line a second Have flow control unit.

In the present patent application, a flow can be understood as an amount or a volume that flows through a surface perpendicular to the flow per unit of time. As a rule, the flow of the liquid CVD medium is given in the unit mg / min and the flow of the carrier gas in the unit sccm (sccm: standard cm ³ / min).

A major advantage of the device according to the invention lies in the controllability of the flow of liquid CVD Medium through the first supply line and the flow of the Carrier gas through the second feed line. The processing unit can the CVD medium and the carrier gas with individually set flows are fed. Through the Flow control of the liquid CVD medium can also indirectly affect the rate, with which the liquid CVD medium in the Processing unit is atomized, controlled. In dependence of the chemical compositions and the physical Properties of the CVD medium and the carrier gas can be their mixture concentrations by the invention Optimize the device in such a way that on the one hand the CVD medium completely passes into the gas phase and on the other hand Condensation of the CVD medium in the supply lines to the CVD Reactor and at the injector are minimized. This Measure extends the service life of the supply lines and of the injection valve considerably.

If the device according to the invention several Has feed branches and thus several processing units, the inflows to each processing unit can be independent from the inflows to the other processing units can be set. Furthermore, by the existence several supply branches for one CVD medium each ensures that various CVD media are not undesirable mix thoroughly.

The flow of the CVD medium and the Flow of the carrier gas is controlled independently become. Such independent controls make it possible For example, the desired operating conditions associated CVD system either via the first Flow control unit or via the second flow control unit adjust. The reason for this is that after the Atomizing principle working device according to the invention both a change in the flow of the liquid CVD medium as well as a change in the flow of the carrier gas Concentration ratio, which is in the processing unit exists between the CVD medium and the carrier gas, directly affected.

So that the inflows of the CVD medium and the carrier gas to the Processing unit kept at predetermined values it is particularly advantageous to be in the device according to the invention a flow control arrangement integrate. The flow control arrangement includes for example measuring devices for measuring the flows through the first and the second lead, the two described above Flow control units and a control unit, which the flows through the two supply lines to predetermined and regulates adjustable values. It can also be provided that regulation only takes place in one of the two supply lines.

Furthermore, it is advantageous for the processing unit to connect a liquid sensor. By means of the Liquid sensor can determine whether the atomization of the CVD medium runs optimally in the processing unit. For example, it can also be provided that with the Liquid sensor delivered measurements Flow control arrangement is fed. In this case the Liquid sensor in the flow control function of the take over the aforementioned measuring device.

According to advantageous embodiments of the invention upstream and downstream of the first Flow control unit shut-off valves arranged. You can also advantageously upstream and downstream of the second Flow control unit additional shut-off valves may be provided. To the one of these measures is particularly advantageous for Exchange of a flow control unit. Due to the Shut-off valves can be the two flow control units be decoupled from the supply lines and from the supply lines be removed without the vacuum in the Supply lines is impaired. On the other hand, these are measures advantageous if a certain CVD medium during the Operation of the associated CVD system is not required. In in this case, the inflow of the relevant CVD Medium and the carrier gas to the associated Close the feed line, causing signs of wear can be reduced by the presence of the CVD medium in the Leads are caused.

A particularly preferred embodiment of the invention is characterized in that a plurality of On the output side, these branches lead to a common supply line are summarized, which the CVD reactor by a Gas inlet feeds. This will reduce the number of gas inlets on CVD reactor reduced, which has the consequence that the Probability of a leak in the vacuum seal of the CVD Reactor is also reduced.

A method according to the invention relates to the supply of at least one gas mixture to a CVD reactor. At least a gas mixture is created by atomizing a liquid CVD Medium generated in a carrier gas. This will be the first liquid CVD medium in a processing unit through a Injector converted into the gas phase and there with the Carrier gas mixed. An essential idea of the invention consists of the inflows of the liquid CVD medium and the carrier gas is controlled to the processing unit become.

The advantage of the method according to the invention is that that by controlling the inflows of the CVD medium and the Carrier gas to the processing unit an optimal Mixing of the two gases in the processing unit enables becomes. This will strive for the gaseous CVD medium kept as low as possible for condensation, so that Deposits of the CVD medium in the supply lines and on the Injection valve and the resulting impairment of the Operation of the associated CVD system can be minimized.

Another aspect of the invention relates to a device for supplying gases to a CVD reactor, which feed lines for CVD media and / or gases to the CVD reactor and one Cleaning arrangement for pumping liquid residues from the Has supply lines. The cleaning arrangement can over Valves are coupled to the supply lines. During the Cleaning process, gases containing the liquid residues are not pumped through the CVD reactor. Furthermore have the cleaning arrangement and the CVD reactor common pump on.

With this device, both such Pump off any liquid residues that are in after the operation of the CVD system the supply lines for the liquid CVD media remained are, as well as those liquid residues that are characterized by Condensation of the gaseous CVD media in the supply lines for which have formed gas mixtures to the CVD reactor. By Such cleaning measures become deposits of CVD media reduced in the feed lines to the CVD reactor. An advantage The present device is that when pumping resulting gases are not pumped through the CVD reactor. This prevents the gaseous residues of the CVD media contaminate the CVD reactor. Another Advantage lies in the shared use of both a pump for cleaning the supply lines as well as for the Vacuum generation in the CVD reactor. This will increase the number of required pumps reduced to a minimum.

The device according to the invention advantageously has a bypass line, which connects the supply lines to the pump combines. The bypass line enables the pump to be pumped out Gases without them crossing the CVD reactor. The Bypass line therefore represents a simple one Possibility of implementing the cleaning arrangement.

A further advantageous embodiment of the invention provides before that the bypass line is a check valve and / or a Shut-off valve and / or a filter. The Check valve prevents a sudden vacuum leak air penetration into the CVD system at the pump the bypass line. The shut-off valve is during the Cleaning the supply lines open and during normal Operation of the CVD system closed. The filter prevents that residues of CVD media in liquid form in the Pump and damage it.

To remove the CVD reactor from the To be able to decouple the pump can advantageously be a additional shut-off valve between the CVD reactor and the pump be arranged. This prevents intrusion of CVD Media in the CVD reactor and one caused by it Contamination of the CVD reactor during cleaning operation.

In a method according to the invention for cleaning Supply lines for CVD media and / or gases to a CVD reactor liquid residues are pumped out of the supply lines. To For this purpose, a pump is used, which is also called Vacuum pump of the CVD reactor is used. Furthermore during the cleaning of the supply lines gases, which the Liquid residues contained, not pumped through the CVD reactor.

The inventive method has the advantage that in the Cleaning the supply lines the gases that the remove remaining CVD media from the supply lines, cannot be pumped through the CVD reactor. This will make one Contamination of the CVD reactor by these gases locked out. Another advantage is the use of the pump for vacuum generation in the CVD reactor as well as for the cleaning of the supply lines. This means that additional pumps, which are only used for cleaning the supply lines, saved.

The invention is described below in an exemplary manner Reference to the drawing explained in more detail. The shows single figure is a schematic arrangement of a Embodiment of the inventive device for feeding Gases to a CVD reactor.

The figure shows a CVD reactor R, which by a Gas inlet is fed with CVD media M1, M2 and M3. The CVD Media are in liquid states in advance and must therefore first be converted into the gas phase. This takes place in supply branches Z1, Z2 and Z3. Since the Supply branches Z1, Z2 and Z3 in their structure and in their function match, only the Supply branch Z1 described. The structure and function of the Supply branches Z2 and Z3 result from this in an analogous manner.

The CVD medium M1 is fed to the feed branch Z1 in the liquid state. After passing through a 3-way valve 3 WV11, a shut-off valve AV11 and a 3-way valve 3 WV12, the liquid CVD medium M1 flows through a flow control unit DS11 and reaches an injection valve EV1 via a shut-off valve AV14. The feed branch Z1 also has a feed line for a carrier gas T. The carrier gas T first passes through a filter F2 and is then fed to the feed branches Z1, Z2 and Z3. In the feed branch Z1, the carrier gas T successively passes through a shut-off valve AV12, a flow control unit DS12 and a shut-off valve AV13. The liquid CVD medium M1 is then injected into the carrier gas T within a small chamber through the injection valve EV1, as a result of which the CVD medium M1 changes into the gas phase and mixes with the carrier gas T. A liquid sensor FS1 downstream of the injection valve EV1 is used to determine the liquid content of the gas mixture consisting of the CVD medium M1 and the carrier gas T. After flowing through a shut-off valve AV15, the gas mixtures generated in the feed branches Z1, Z2 and Z3 are combined into a common feed line and fed into the CVD reactor R via a shut-off valve AV2 and a filter F3.

It is also possible to have a regulatory arrangement in the to implement the present arrangement. For example, the Flow control units DS11 and DS12 a control loop include. To do this, the rivers through the Flow control units DS11 and DS12 measured and then, for example by means of controllable valves within the Flow control units DS11 and DS12 to specified values regulated. Furthermore, it is also conceivable that for the Regulatory arrangement not the rivers through the Flow control units DS11 and DS12 are measured, but that the liquid sensor FS1 as a measuring device Regulation arrangement serves. If the liquid content of the generated gas mixture can, for example, the flow of Carrier gas T are increased or the flow of the medium M1 is reduced become.

The shut-off valves AV12 and AV13 are replaced when the Flow control unit DS12 required. Through the Shutoff valves AV12 and AV13 can be used Disconnect the flow control unit DS12 from the supply lines and replace them. The same applies to the shut-off valves AV11 and AV14 and the flow control unit DS11. With the help of Shut-off valve AV15 can the branch Z1 from the CVD Reactor R are decoupled. Furthermore, everyone can Supply branches Z1, Z2 and Z3 through the shut-off valve AV2 be decoupled from the CVD reactor R. The filter F3 prevents contamination from entering the CVD Reactor R.

A bypass line BL is provided for cleaning the lines of the present arrangement. The bypass line BL is connected at one end to the supply branches Z1, Z2 and Z3 via the 3-way valves 3 WV11, 3 WV21 and 3 WV31. At its other end, the bypass line BL is connected to a pump P via a check valve RV5, a shutoff valve AV3 and a filter F4. If the respective valves have the corresponding positions, residues of all kinds, in particular liquid residues of the CVD media M1, M2 and M3, can be pumped through the bypass line BL from the feed branches Z1, Z2 and Z3.

The vacuum in the CVD reactor R and the feed branches Z1, Z2 and Z3 are also generated by the pump P. During the Cleaning the supply branches Z1, Z2 and Z3 is the CVD Reactor R from the pump P and the bypass line BL through Shut-off valve AV4 separated. In normal operation it is Shut-off valve AV4 is open and the shut-off valve AV3 is closed so that the bypass line BL from the pump P is decoupled.

In addition, the feed branches Z1, Z2 and Z3 can be flushed with nitrogen N for cleaning purposes. For this purpose, the nitrogen N is flushed through a check valve RV1 and the 3-way valve 3 WV12 through the feed branch Z1. The same applies to the feed branches Z2 and Z3.

Furthermore, the nitrogen N can also be used to purge the CVD Reactor R can be used. For this purpose, the common feed of the feed branches Z1, Z2 and Z3 with Nitrogen N can be fed. The nitrogen N becomes the common supply line to the CVD reactor R via a filter F1 Shut-off valve AV1, a needle valve NV and one Check valve RV4 supplied. This nitrogen supply can also be used to the feed branches Z1, Z2 and Z3 to flush their exits.

Claims (25)

1. Device for supplying gases to a CVD reactor (R), with at least one supply branch (Z1, Z2, Z3) for one Gas mixture, which by atomizing a CVD medium (M1, M2, M3) is generated in a carrier gas (T), the at least one feed branch (Z1, Z2, Z3) a first one Supply line for the liquid CVD medium (M1, M2, M3), a second Supply line for the carrier gas (T) and one of the first and treatment unit fed to the second feed line which, by means of an injection valve (EV1, EV2, EV3) the liquid CVD medium (M1, M2, M3) in the gaseous Condition transferred and mixed with the carrier gas (T), the first feed line a first flow control unit (DS11, DS21, DS31) and the second lead a second Flow control unit (DS12, DS22, DS32) have. 2. Device according to claim 1, characterized, that the two flow control units (DS11, DS21, DS31, DS12, DS22, DS32) an independent control of the Flow of the CVD medium (M1, M2, M3) and the Allow flow of carrier gas (T). 3. Device according to claim 1 or 2, marked by using a flow control arrangement the first and / or the second Flow control unit (DS11, DS21, DS31, DS12, DS22, DS32) a regulation the carrier gas and / or the CVD medium flow allows. 4. Device according to one or more of the preceding Expectations, characterized, that the processing unit has a liquid sensor (FS1, FS2, F3) is connected downstream, with its measured values if necessary especially the flow control arrangement is fed. 5. Device according to one or more of the preceding Expectations, marked by a first shut-off valve (AV11, AV21, AV31), which in the first feed line upstream of the first Flow control unit (DS11, DS21, DS31) is arranged, and / or a second shut-off valve (AV12, AV22, AV32), which in the second feed line upstream of the second Flow control unit (DS12, DS22, DS32) arranged is. 6. Device according to one or more of the preceding Expectations, marked by a third shut-off valve (AV14, AV24, AV34), which in the first feed line downstream of the first Flow control unit (DS11, DS21, DS31) is arranged, and / or a fourth shut-off valve (AV13, AV23, AV33), which in the second feed line downstream of the second Flow control unit (DS12, DS22, DS32) arranged is. 7. Device according to one or more of the preceding Expectations, marked by a fifth shut-off valve (AV15, AV25, AV35), which is arranged downstream of the processing unit. 8. Device according to one or more of the preceding Expectations, marked by a plurality of feed branches (Z1, Z2, Z3), the on the output side lead into a common supply line, which is connected to a gas inlet of the CVD reactor (R). 9. The device according to claim 8, characterized, that the common supply line is a sixth shut-off valve (AV2). 10. Method for supplying at least one gas mixture, which by atomizing a CVD medium (M1, M2, M3) in a carrier gas (T) is generated, to a CVD reactor (R), the initially liquid CVD medium (M1, M2, M3) in one Processing unit using an injection valve (EV1, EV2, EV3) is converted into the gaseous state and with the carrier gas (T) is mixed, and wherein the inflow of liquid CVD medium (M1, M2, M3) and the inflow of the Carrier gas (T) can be controlled to the processing unit. 11. The method according to claim 10, characterized, that the inflow of the liquid CVD medium (M1, M2, M3) and the inflow of the carrier gas (T) to the Processing unit can be controlled independently. 12. The method according to claim 10 or 11, characterized, that the inflow of the liquid CVD medium (M1, M2, M3) and / or the inflow of the carrier gas (T) to the Processing unit are regulated. 13. The method according to claim one or more of the claims 10 to 12, characterized, that the liquid portion of the at least one Gas mixture is examined, and if necessary, in particular the Control of the inflow of the liquid CVD medium (M1, M2, M3) and / or the regulation of the inflow of the carrier gas (T) depending on the test result be performed. 14. The method according to one or more of claims 10 to 13 characterized, that the inflow of the CVD medium (M1, M2, M3) to the Processing unit through a first shut-off valve (AV14, AV24, AV34) is controlled and / or the inflow of the Carrier gas (T) to the processing unit through a second Shut-off valve (AV13, AV23, AV33) is controlled. 15. The method according to one or more of claims 10 to 14 characterized, that the outflow of the at least one gas mixture from the Processing unit through a third shut-off valve (AV15, AV25, AV35) is controlled. 16. The method according to one or more of claims 10 to 15 marked by a plurality of gas mixtures that are common Supply line is fed to the CVD reactor (R). 17. The method according to claim 16, characterized, that the inflow of the gas mixtures to the CVD reactor (R) is controlled by a fourth shut-off valve (AV2). 18. Device for supplying gases to a CVD reactor (R), with
Supply lines for CVD media (M1, M2, M3) and / or gases to the CVD reactor (R), and
a cleaning arrangement for pumping liquid residues from the supply lines, wherein
the cleaning arrangement can be coupled to the supply lines via valves ( 3 WV11, 3 WV21, 3 WV31),
the cleaning arrangement and the CVD reactor (R) have a common pump (P), and
the cleaning arrangement is designed such that gases which are pumped out during the cleaning and contain the liquid residues are pumped past the CVD reactor (R). 19. The apparatus according to claim 18, marked by a bypass line (BL) which connects the supply lines with the Pump (P) connects. 20. The apparatus according to claim 19, characterized, that the bypass line (BL) has a check valve (RV5) and / or a first shut-off valve (AV3) and / or a Has filter (F4). 21. The device according to one or more of claims 18 to 20 marked by a second shut-off valve (AV4), which is located between the CVD Reactor (R) and the pump (P) is arranged. 22. Process for cleaning supply lines for CVD media (M1, M2, M3) and / or gases to a CVD reactor (R), in which liquid residues are pumped out of the supply lines, whereby
a pump (P) which is common to the CVD reactor (R) is used for cleaning the feed lines, and
During the cleaning of the supply lines, gases containing the liquid residues are pumped past the CVD reactor (R). 23. The method according to claim 22, characterized, that the supply lines with the pump (P) through a Bypass line (BL) can be connected. 24. The method according to claim 23, characterized, that the bypass line (BL) has a check valve (RV5) and / or a first shut-off valve (AV3) and / or a Has filter (F4). 25. The method according to one or more of claims 22 to 24 characterized, that before cleaning the supply lines the CVD reactor (R) from the pump (P) through a second shut-off valve (AV4) is decoupled.