JP4445702B2 - Liquid material vaporization supply apparatus, thin film deposition apparatus, and liquid material vaporization supply method to thin film deposition apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid material vaporization supply apparatus, a thin film deposition apparatus, and a liquid material vaporization supply method to a thin film deposition apparatus.
[0002]
[Background Art and Problems to be Solved by the Invention]
In general, when a liquid material is vaporized in a chemical vapor deposition (CVD) process (hereinafter referred to as a CVD process), the liquid material is mainly vaporized by heating and supplied under reduced pressure. As a result, a thin film was deposited on the target substrate which is the processing target. FIG. 3 is a diagram for explaining a conventional liquid material vaporization supply apparatus and a liquid material vaporization supply method to a thin film deposition apparatus.
[0003]
In FIG. 3, reference numeral 21 denotes a vaporizer that vaporizes a liquid material LM such as TEOS (Tetra Ethoxysilane) by heating with a heater 21a, for example, and 22 denotes a vaporized liquid material LM (hereinafter referred to as vaporized material LMG). , A reaction chamber for depositing a thin film on a target substrate such as a silicon substrate, 23 is a pipe for supplying the liquid material LM to the vaporizer 21, 24 is a supply pipe for supplying the vaporized material LMG to the reaction chamber 22, and 25 is a reaction. This is a vacuum pump provided on the downstream side of the chamber 22.
[0004]
The reaction chamber 22 is a chamber in which, for example, a shower head 26 filled with the vaporized material LMG supplied by the supply pipe 24 and a substrate 27 to be processed are disposed immediately below the shower head 26 and the inside is sucked to a state close to a vacuum. 28. The shower head 26 and the chamber 28 are separated from each other by a shower panel 29 having a large number of small holes. Further, 30 is a heater for heating the supply pipe 24 and the shower head 26, and 31 is a constant flow rate supply device for adjusting the flow rate of the liquid material LM supplied to the vaporizer 21 to a constant flow rate.
[0005]
The heater 21 a supplies a sufficient amount of heat to vaporize the liquid material LM. For example, when heated to 100 ° C., the liquid material LM vaporizes, and the vaporized material LMG passes through the supply pipe 24 and the shower head 26. Then, the substrate 27 can be processed by being sprayed evenly onto the substrate 27. At this time, the heater 30 needs to be set to be somewhat higher than the temperature of the heater 21a (eg, 110 ° C. in this example) so that no condensation occurs in the supply pipe 24 and the shower head 26.
[0006]
However, when vaporization is performed mainly using the heater 21a as described above, heat for heating to a sufficiently high temperature is required as the liquid material LM is vaporized, which is higher than the thermal decomposition temperature of the liquid material LM. There was a possibility. Further, it is conceivable that the material is thermally decomposed in the vaporizer 21, and there is a concern that the processing product of the substrate 27 may be generated due to the reaction product. In addition, since the heat from the heater 30 is applied so that the vaporized material LMG that has once vaporized does not condense again, a reaction product may be generated from the vaporized material LMG in the supply pipe 24 due to this heat. . That is, it has been extremely difficult to control the optimum evaporation conditions for the vaporized material LMG.
[0007]
On the other hand, if the heat supplied for vaporization of the liquid material LM is suppressed to the minimum necessary level for vaporization, it is possible to suppress the temperature below the thermal decomposition temperature of the liquid material LM, but the amount of heat supplied from the heater 21a. Therefore, the vaporization flow rate of the liquid material LM may be limited. In addition, when the amount of heat supplied to quickly vaporize the liquid material LM is increased, decomposition and reliquefaction may occur in the portion of the supply pipe 24 from the vaporizer 21 to the reaction chamber 28. In addition, periodic maintenance and inspection of the supply pipe 24, the shower head 26, the shower panel 29, and the like may be necessary.
[0008]
In addition to these, when the liquid material LM is vaporized and supplied by the amount of heat supplied by the heater 21a, a complicated constant flow rate supply is required in order to accurately determine the amount of the liquid material LM supplied to the reaction chamber 28. It is necessary to combine the device 31 and the like, and the measurement of the flow rate is complicated. In addition, even if the flow rate is controlled by an open / close valve (not shown) in the vaporizer 21, the flow rate of the vaporized material LMG follows the control with a delay, so this flow rate control is difficult, and the liquid material LM is not necessarily controlled. The amount used could not be optimized.
[0009]
The present invention has been made in consideration of the above-mentioned matters, and its purpose is to be able to vaporize and supply a liquid material with a minimum amount of heating in a CVD process, and to quickly supply a predetermined amount of many materials. To provide a liquid material vaporization supply device, a thin film deposition device, and a liquid material vaporization supply method that can be vaporized accurately.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a liquid material vaporization supply apparatus of the present invention is used in a thin film deposition apparatus for depositing a thin film on a workpiece by supplying the vaporized liquid material into a reaction chamber under reduced pressure. A pressure unit that applies pressure to the material, an injector body that is pressurized by the pressure unit and filled with a liquid material mixed with an additive solution that can form a two-phase region in order to lower the boiling point, and a tip of the injector body. Addition that has a formed injection port and an on-off valve that opens and closes the injection port, and that can be pressurized by the pressurizing means by opening the on-off valve to form a two-phase region to lower the boiling point It is characterized in that the liquid material can be vaporized by reduced-pressure boiling caused by spraying the liquid material mixed with the liquid under reduced pressure to generate a pressure difference . (Claim 1)
The liquid material vaporization supply apparatus of the present invention is used in a thin film deposition apparatus that deposits a thin film on a workpiece by supplying the vaporized liquid material into a reaction chamber under reduced pressure, and applies pressure to the liquid material. A pressure unit, a boiling point adjusting unit that lowers the boiling point of the liquid material by mixing an additive liquid that can form a two-phase region with the liquid material, and a liquid that is pressurized by the pressure unit and mixed with the additive liquid It has an injector body filled with a material, an injection port formed at the tip of the injector body, and an on-off valve that opens and closes the injection port. By opening the on-off valve , pressurization is performed by the pressurizing means. It may be characterized in that the vaporizable liquid material by boiling under reduced pressure occurring in the liquid material mixed with the additive solution to cause a pressure differential by spraying under vacuum is (claim 2).
[0011]
The reduced-pressure boiling or reduced-pressure boiling phenomenon in the present specification refers to a phenomenon in which the liquid boils and vaporizes when the external pressure of the opened liquid becomes smaller than its vapor pressure. Uses this vacuum boiling phenomenon to spray a predetermined amount of liquid material with the minimum amount of heat instantaneously by spraying the pressurized liquid material into the reaction chamber (under reduced pressure) reduced by vacuum suction. It is something that vaporizes.
[0012]
In particular, by supplying a liquid material pressurized to a high pressure under reduced pressure, the pressure difference is increased to facilitate vaporization under reduced pressure. Accordingly, since the liquid material can be vaporized with a minimum amount of heat without heating the liquid material to a high temperature, generation of a reaction product accompanying the heating of the liquid material can be prevented. That is, it is possible to accurately control the optimum evaporation conditions.
[0013]
Also, the amount of liquid material that is vaporized and supplied is easily and accurately determined from the pressure applied to the liquid material and the opening time of the on-off valve, the cross-sectional area of the injection port and the viscosity of the liquid material, or the number of operations of the injector body. There is no need to combine a complicated constant flow rate supply device or the like as in the prior art. That is, the amount of liquid material used can be optimized.
[0014]
When a heating means for heating the liquid material is provided (Claim 3), the reduced-pressure boiling phenomenon can be promoted and vaporization can be facilitated. Note that the temperature of the liquid material heated by the heating means is set so that no reaction product is generated from the liquid material. Moreover, since the vaporization efficiency is improved, more liquid material can be vaporized in a short time.
[0015]
When the opening / closing valve is composed of a piston that blocks the tip of the injection port and an electromagnetic coil that enables the opening / closing control of the injection port by electromagnetic induction (Claim 4), the opening / closing of the opening / closing valve can be controlled at high speed. The amount of liquid material that is vaporized and supplied can be controlled accurately.
[0016]
In addition, by having a boiling point adjustment unit that lowers the boiling point of the liquid material by mixing a predetermined ratio of an additive liquid that can form a two-phase region with the liquid material, the boiling point of the liquid material is lowered, thereby facilitating the reduced-pressure boiling phenomenon. Therefore, it is possible to suppress the supply of heat energy.
[0017]
The additive liquid that can form a two-phase region is a solution in which the liquid material and the additive liquid are not polar to each other and can be dissolved in each other. In addition, the additive solution needs to have a low critical solution temperature and a low critical solution temperature. That is, when the liquid material is TEOS, n-Pentane, diethyl ether, or the like can be used as an additive liquid that can form a two-phase region.
[0018]
The thin film deposition apparatus of the present invention includes the liquid material vaporization supply apparatus, and the injection port is provided in the reaction chamber. (Claim 5)
[0019]
By providing the injection port of the liquid material vaporization supply device in the reaction chamber, it is possible to prevent the liquid material from being decomposed or reliquefied due to the circulation of piping or the like. That is, it is not necessary to apply heat from the outside so that the vaporized liquid material can be kept in a vaporized state, contributing to energy saving and controlling the optimum evaporation conditions reliably.
[0020]
The liquid material vaporization supply method of the present invention is a method of vaporizing and supplying a liquid material into a reaction chamber of a thin film deposition apparatus, and applies pressure to the liquid material and reacts the pressurized liquid material under reduced pressure. An additive liquid that can be vaporized by boiling under reduced pressure caused by generating a pressure difference at the same time as the liquid material is supplied by being injected into the chamber, and can form a two-phase region with the liquid material before the vaporization To lower the boiling point (claim 6).
[0021]
By injecting the liquid material into the reaction chamber, the liquid material evaporated by boiling under reduced pressure can be injected onto the object to be processed without waste. In general, the surface of the object to be processed can be processed by spraying the vaporized liquid material immediately above the object to be processed. However, when the liquid material evaporated immediately below the object to be processed is sprayed, the lower surface of the object to be processed is processed. it can. Further, by spraying the pressurized liquid material into the reaction chamber under reduced pressure, a large pressure difference can be obtained and the vaporization efficiency is improved, so that more liquid material can be vaporized in a short time.
[0022]
When the pressurized liquid material is heated and then sprayed (Claim 7), the liquid material can be vaporized more reliably, and the reliability is improved accordingly.
[0023]
When the reaction time in the reaction chamber is controlled by controlling the jetting time of the liquid material (claim 8), the amount of the vaporized liquid material can be reliably and easily controlled. That is, the chemical reaction in the reaction chamber can be appropriately performed.
[0024]
Furthermore, it is possible to reliably vaporize a liquid material having a high boiling point by mixing a predetermined ratio of an additive liquid capable of forming a two-phase region with the liquid material.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an overall configuration of a thin film deposition apparatus 1 by a CVD method using the liquid material vaporization supply apparatus of the present invention, and FIG. 2 shows a liquid material vaporization supply constituting the main part of the thin film deposition apparatus 1 2 is a diagram showing a configuration of the device 2. FIG.
[0026]
In FIG. 1, 3 is a liquid material tank containing a liquid material LM, 4 is an additive liquid tank containing an additive liquid LA added to the liquid material LM, 5 is a switching valve (for example, an electromagnetic valve), and 6 is a liquid material. A supply pipe that supplies LM, 7 is a supply pipe that supplies the additive liquid LA, 8 is a mixer that is connected to the supply pipes 6 and 7 and mixes both liquids LM and LA at a predetermined ratio, and 9 is a mixed liquid (Hereinafter, in order to simplify the description, this mixed liquid is expressed as a liquid material LM + LA) and supply piping 10 feeds a high-pressure inert gas Gas into the liquid material tank 3 and the additive liquid tank 4, respectively. This is a pressurizing means for sending out the liquid material LM and the additive liquid LA in a pressurized state.
[0027]
In this example, an example in which the additive liquid LA is mixed with the liquid material LM is shown. Therefore, in the following description, the liquid material LM + LA will be described. However, the present invention mixes the additive liquid LA with the liquid material LM. It is not limited to forming a two-phase region. In this case, it goes without saying that the additive liquid tank 4, the supply pipe 7, and the mixer 8 can be omitted from the configuration of the thin film deposition apparatus 1.
[0028]
11 is a reaction chamber (chamber) for depositing a thin film on a target substrate 12 such as a silicon substrate to be processed, and 13 is a suction pump for evacuating the inside of the reaction chamber 11. The liquid material vaporization supply device 2 of the present invention is attached to the upper surface of the reaction chamber 11 and is disposed immediately above (closest to) the target substrate 12 in the reaction chamber 11.
[0029]
The liquid material LM of this example is TEOS generally used in a semiconductor manufacturing process, for example, and the additive liquid LA is n-Pentane (normal pentane). Since both the liquids LM and LA are liquids that form a two-phase region, the boiling point of the liquid material LM can be lowered by mixing the two liquids LM and LA. For example, in the case of this example, the boiling point can be lowered by 100 ° C. by mixing 60% of n-Pentane as the additive liquid LA with respect to the liquid material LM (TEOS) by the mixer 8.
[0030]
The liquid material vaporization supply device 2 shown in FIG. 2 is, for example, a substantially cylindrical injector body 14, an on-off valve 15, a solenoid 16 that electrically slides on the on-off valve 15, and an on-off valve 15 using the solenoid 16. And a control circuit 17 for operating. In the case of this example, a pressure gauge 18 for measuring the pressure P of the liquid material LM + LA supplied to the injector body 14 and a heater 19 using electric heat as a heating means are provided.
[0031]
The on-off valve 15 is a piston that is located in the internal space 14a of the injector body 14 and blocks the tip of the injection port 14b by pressing the spring 15s, and an umbrella-shaped flange 15b and an annular groove 15c are formed at the tip 15a. is doing. The configuration of the tip portion 15a is adjusted according to the viscosity and pressure P of the liquid material LM + LA so that the liquid material LM + LA ejected from the ejection port 14b can be sprayed evenly while forming a predetermined angle α (see FIG. 1). The shape has been adjusted.
[0032]
The control circuit 17 opens the injection port 14b by driving the solenoid 16 for a time required to spray a predetermined amount of the liquid material LM while monitoring the pressure P of the liquid material LM + LA using the pressure gauge 18. In addition, the heater 19 is used to heat the vicinity of the injection port 14b of the injector body 14 to, for example, about several tens of degrees Celsius (slightly higher than room temperature). That is, heat energy is supplied to the liquid material LM + LA by heating to a temperature at which the boiling point of the liquid material LM + LA or the temperature of the liquid material LM + LA is lower than that causing a chemical reaction.
[0033]
In addition, the structure of the injector main body 14 mentioned above shows a mere example, and does not limit this invention. That is, the pressurizing means 10 is not limited to pumping the inert gas Gas into the liquid material tank 3 and the additive liquid tank 4, and as shown by a phantom line in FIG. A pressurizing pump 10 ′ as a pressurizing unit for the material LM + LA may be provided. In addition, a pump is built in the injector body 14, and the injection amount of the liquid material LM + LA can be adjusted by the number of times of driving of the pump built in the injector body 14. Furthermore, stepwise pressurization can be performed by appropriately combining pressurizing means 10 and 10 '(including a pump built in the injector body).
[0034]
The operation of the liquid material vaporization and supply apparatus 1 of the present example shown in FIGS. 1 and 2 will be described. The liquid material LM + LA in a state is supplied. Here, when the control circuit 17 heats the vicinity of the injection port 14 b using the heater 19 and opens the injection port 14 b using the solenoid 16, the liquid material LM + LA reacts after the temperature is increased by the heat from the heater 19. Spraying is performed uniformly while forming an angle α in the chamber 11.
[0035]
At this time, since the liquid material LM + LA diverges from the pressurized state by the pressurizing means 10 to the reduced pressure state at once, a reduced pressure boiling phenomenon occurs in the sprayed liquid material LM + LA, and the whole amount is vaporized at once by the reduced pressure boiling spray. . In particular, in this example, since the two-phase region is formed by mixing the additive liquid LA with the liquid material LM, the boiling point of the liquid material LM + LA forming the two-phase region is lowered to be suitable for boiling under reduced pressure, Since the liquid material LM + LA is heated by the heater 19 in advance, vaporization is further promoted, and the liquid material LM + LA can be vaporized instantaneously. Even if the flow rate of the liquid material LM + LA is increased, the entire amount is definitely vaporized. The target substrate 12 can be processed.
[0036]
That is, more liquid material LM can be vaporized in a short time, and the time taken for vaporization of liquid material LM can be drastically shortened, so the time taken for the CVD process can be shortened. Needless to say, depending on the type of the liquid material LM, vaporization can be performed at room temperature without heating by the heater 19. The heater (heating means) 19 may be an electric heater or a high frequency electromagnetic induction heater.
[0037]
As described above, in this example, since the additive liquid LA is mixed with the liquid material LM so as to form the two-phase region, the two-phase can be obtained regardless of whether the boiling point of the liquid material LM is high or low. By selecting an appropriate additive liquid LA that can form a state and adding this additive liquid LA (organic substance), the evaporation control of the liquid material LM + LA can be performed accurately, and the optimal evaporation condition of the liquid material LM Can be controlled. However, in the present invention, it is not always necessary to form a two-phase region, and it is not necessary to mix the additive liquid LA depending on the type of the liquid material LM.
[0038]
In other words, it is possible to omit the boiling point adjusting unit including the additive liquid tank 4, the supply pipe 7, and the mixer 8. Further, by providing the boiling point adjusting portions 4, 7, and 8 as in this example, the liquid material LM and the additive liquid LA can be stored separately, and management of both the liquids LM and LA is facilitated accordingly. The material LM and the additive liquid LA may be mixed and stored in the liquid material tank 3. Also in this case, the boiling point adjusting portions 4, 7, and 8 can be omitted.
[0039]
In addition, by using the liquid material vaporization supply apparatus 1 of the present invention, the amount of vaporized liquid material LM supplied to the CVD process can be accurately controlled by the pressure P and the opening time of the injection port 14b. The control circuit 17 performs this control. Further, the vaporization of the liquid material LM occurs instantaneously in the reaction chamber 11 and is directly supplied to the target substrate 12 because it is directly above (closest to) the target substrate 12, and the vaporized material LMG is supplied to the reaction chamber as in the conventional case. There is no loss of the liquid material LM due to the supply pipe 24, the shower head 26, and the like existing in the supply path 28. When the injector main body 14 is provided immediately below (closest to) the target substrate 12, the lower surface of the target substrate 12 can be processed.
[0040]
Therefore, it is possible to accurately control the amount of the liquid material LM supplied to the target substrate 12 and reliably manage the process more accurately. Further, the start and end of the vaporization supply of the liquid material LM can be accurately controlled in terms of time, and the time delay can be eliminated as much as possible.
[0041]
That is, the optimization can be achieved without waste of the liquid material LM and waste of heat energy as occurred in the conventional thin film deposition apparatus. In addition, the process can be managed more accurately by reliably eliminating the alteration of the liquid material LM caused by inadvertent application of heat.
[0042]
【The invention's effect】
As described above, in the present invention, the liquid material can be vaporized and supplied by the minimum necessary heating in the CVD process, and not only can a large number of materials be vaporized quickly within a short time, but also the amount of liquid material to vaporize and the processing time can be reduced. It can be controlled accurately.
[Brief description of the drawings]
FIG. 1 is an overall view showing an example of a thin film deposition apparatus of the present invention.
FIG. 2 is a diagram showing a configuration of a liquid material vaporization supply apparatus used in the thin film deposition apparatus.
FIG. 3 is a diagram showing a configuration of a conventional thin film deposition apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Thin film deposition apparatus, 2 ... Liquid material vaporization supply apparatus, 4, 7, 8 ... Boiling point control part, 10 ... Pressurization means, 11 ... Reaction chamber, 12 ... Processing object, 14 ... Injector main body, 14b ... Injection port, DESCRIPTION OF SYMBOLS 15 ... On-off valve (piston), 16 ... Electromagnetic coil, 19 ... Heating means, LA ... Additive liquid, LM ... Liquid material.

Claims (8)

Used in thin film deposition equipment that deposits a thin film on the workpiece by supplying the vaporized liquid material into the reaction chamber under reduced pressure.
Pressurizing means for applying pressure to the liquid material;
An injector body filled with a liquid material mixed with an additive liquid that is pressurized by this pressurizing means and can form a two-phase region in order to lower the boiling point;
An injection port formed at the tip of the injector body;
An opening and closing valve for opening and closing the injection port,
By opening the on-off valve, a pressure difference is generated by spraying under reduced pressure a liquid material mixed with an additive liquid that is pressurized by the pressurizing means and can form a two-phase region in order to lower the boiling point. liquid material vaporizing supply apparatus being characterized in that the vaporizable liquid material by boiling under reduced pressure to occur. Used in thin film deposition equipment that deposits a thin film on the workpiece by supplying the vaporized liquid material into the reaction chamber under reduced pressure.
Pressurizing means for applying pressure to the liquid material;
A boiling point adjusting unit that lowers the boiling point of the liquid material by mixing an additive solution capable of forming a two-phase region with the liquid material;
An injector body filled with a liquid material pressurized by the pressurizing means and mixed with the additive liquid;
An injection port formed at the tip of the injector body;
An opening and closing valve for opening and closing the injection port,
By opening the on-off valve, the liquid material can be vaporized by boiling under reduced pressure caused by spraying the liquid material pressurized by the pressurizing means and mixed with the additive liquid under reduced pressure to generate a pressure difference. An apparatus for vaporizing and supplying a liquid material, wherein:   The liquid material vaporization supply apparatus according to claim 1, further comprising a heating unit configured to heat the liquid material.   The liquid material vaporization supply device according to any one of claims 1 to 3, wherein the on-off valve includes a piston that blocks the tip of the injection port, and an electromagnetic coil that enables opening / closing control of the injection port by electromagnetic induction.   A thin film deposition apparatus comprising the liquid material vaporization supply apparatus according to claim 1, wherein the injection port is provided in the reaction chamber. A method of vaporizing and supplying a liquid material into a reaction chamber of a thin film deposition apparatus, and applying pressure to the liquid material and injecting the pressurized liquid material into a reaction chamber under reduced pressure, It is vaporized by boiling under reduced pressure caused by causing a pressure difference at the same time as being supplied, and the liquid material before vaporization is mixed with an additive solution capable of forming a two-phase region with the liquid material to lower the boiling point. Liquid material vaporization supply method.   The liquid material vaporization supply method according to claim 6, wherein the pressurized liquid material is sprayed after being heated.   The liquid material vaporization supply method according to claim 6 or 7, wherein a reaction time in the reaction chamber is controlled by controlling an ejection time of the liquid material.

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