Patent Application
20080066787
Embodiments of the present invention will be described below with reference to drawings.
First, a treatment apparatus according to a first embodiment of the present invention is shown in
The treatment apparatus of
The treatment apparatus main body 10 is formed as a plate-like container and has a treatment tank 11 in which a substrate 100 to be treated is accommodated and treated; and a heating device 15 is incorporated in the treatment tank 11. The main body has heating devices 16 and 17 in front of and behind the treatment tank 11.
There are provided downstream of the treatment apparatus main body 10 a first pressure control valve 51 for controlling the pressure in the treatment apparatus main body 10 and the gas-liquid separation-collection device 60 for separating a fluid discharged from the treatment apparatus main body 10 into carbon dioxide gas and a chemical to collect the chemical.
The carbon dioxide supply device 20 is formed of a carbon dioxide cylinder in which pressurized and liquidated carbon dioxide is contained.
An opening-closing valve 24 is provided for the carbon dioxide supply device 20. A pipe 71 is connected to the carbon dioxide supply device 20. The pipe 71 connects the carbon dioxide supply device 20, a cooling device 21 for cooling and liquidating CO2 gas, and a pressurizing device 22 and a heating device 23 for transforming the liquid carbon dioxide into a supercritical state to each other, and is connected to the mixing tank 40.
The pressurizing device 22 is formed of a pressurizing pump or the like, and the heating device 23 is formed of a line heater or the like.
An opening-closing valve 31 is provided for the chemical supply device 30. A pipe 72 is connected to the chemical supply device 30. The pipe 72 connects the chemical supply device 30, a pressurizing device 32, and a heating device 33 to each other, and is connected to the pipe 71 in which supercritical carbon dioxide flows.
Since supercritical carbon dioxide flowing in the pipe 71 is brought into contact with a chemical flowing in the pipe 72 in a junction of the pipe 71 and the pipe 72, the junction forms a mixing device 80 for mixing the supercritical carbon dioxide with the chemical.
The mixing tank 40 has a solubility observation window 42 for observing whether or not carbon dioxide is mixed with an additive; and a heating device 44, such as a built-in heater, is incorporated in an outer wall of the tank.
The pipe 71 into which a fluid mixture of supercritical carbon dioxide with a chemical flows and a pipe 73 from which the fluid is discharged are connected to the mixing tank 40.
The three-way valve 50 is provided between the mixing tank 40 and the treatment apparatus main body 10. The three-way valve 50 is formed to connect the pipe 73 at the side of the mixing tank 40 to a pipe 74 at the side of the treatment apparatus main body 10 and branch a pipe 75 from the pipe 73 and the pipe 74.
The three-way valve 50 is formed so that a supply route of a fluid flowing from the pipe 73 at the side of the mixing tank 40 may be switched between the pipe 74 and the pipe 75.
A second pressure control valve 52 is provided for the pipe 75 divided by the three-way valve 50. The pipe 75 is provided with a gas-liquid separation-collection device 61 for separating a fluid discharged through the three-way valve 50 and the second pressure control valve 52 into carbon dioxide gas and a chemical and to collect the chemical.
The second pressure control valve 52 has a configuration in which the valve may control the pressure in the mixing tank 40 and the mixing device 80 independently from the treatment apparatus main body 10 when the three-way valve 50 blocks the pipe 74 and connects the pipe 73 to the pipe 75.
Next, a method for treating a substrate using the treatment apparatus according to the above-described first embodiment will be described.
First, a substrate 100 to be treated is accommodated in the treatment tank 11 and a cover is closed, so that the treatment tank 111 is sealed.
Then, the first pressure control valve 51 is adequately closed so that the pressure in the treatment tank 11 may be controlled to retain a predetermined treatment pressure (26 MPa, for example). The three-way valve 50 is switched so that a fluid from the pipe 73 is supplied to the pipe 74.
Then, the opening-closing valve 24 is opened to supply carbon dioxide from the carbon dioxide supply device 20.
The carbon dioxide supplied from the carbon dioxide supply device 20 is cooled using the cooling device 21 and transformed into a liquid state. The carbon dioxide in a liquid state is pressurized to 7.3 MPa or higher using the pressurizing device 22 and heated to 50° C. by the heating device 23 and thus is transformed into a supercritical state.
The carbon dioxide in a supercritical state is introduced into the treatment apparatus main body 10 through the mixing tank 40 and the three-way valve 50.
The pressure in the treatment tank 11 is controlled to be a pressure for treating the substrate 100 (26 MPa, for example) by using the first pressure control valve 51. When the pressure in the treatment tank 11 includes a predetermined pressure or higher, the first pressure control valve 51 is opened to discharge the supercritical carbon dioxide, so that the pressure in the treatment tank 11 may be kept constant. The supercritical carbon dioxide discharged from the treatment tank 11 is discharged to the gas-liquid separation-collection device 60 by opening the first pressure control valve 51.
Subsequent treatment of the substrate may be rapidly performed by pre-controlling the pressure in the treatment tank 11 at a predetermined treatment pressure.
Then, a flow of the supercritical carbon dioxide from the pipe 73 is switched from the pipe 74 to the pipe 75 by using the three-way valve 50. Then, the second pressure control valve 52 is adequately closed so that the pressure in the mixing tank 40 may be controlled to be higher than the. treatment pressure in the treatment tank 11 (30 MPa, for example).
Thereafter, the pressure in the mixing tank 40 is higher than the treatment pressure in the treatment tank 11 with the supercritical carbon dioxide supplied from the pipe 71.
Then, the opening-closing valve 31 is opened to supply a chemical from the chemical supply device 30.
The chemical is controlled to be at a predetermined pressure and temperature using the pressurizing device 32 and the heating device 33 and is supplied to the pipe 71 through the pipe 72. At this time, the chemical is mixed at a ratio of 1 to 5 wt % based on the carbon dioxide already heated and pressurized, for example.
The supercritical carbon dioxide and the chemical are brought into contact with each other in the mixing device 80, and are supplied to the mixing tank 40 through the pipe 71.
The supercritical carbon dioxide is not homogeneously mixed with the chemical for a certain time after the start of mixing. Thus, a phase of the supercritical carbon dioxide and a phase of the chemical are separated in the mixing tank 40, and an interface between the two phases may be observed from the solubility observation window 42.
The supercritical carbon dioxide and the chemical are discharged to the gas-liquid separation-collection device 61 through the three-way valve 50 and the second pressure control valve 52 until the chemical is stably and homogeneously dissolved.
The chemical is completely dissolved in the supercritical carbon dioxide until the interface between the two phases may not be observed from the solubility observation window 42. The three-way valve 50 is switched to from the pipe 75 and the pipe 74, so that a fluid from the mixing tank 40 may be supplied to the treatment tank 11.
The supercritical carbon dioxide in which the chemical is completely dissolved is supplied to the treatment tank 11 from the mixing tank 40 through the pipe 73, the three-way valve 50, the pipe 74, and the heating device 16. At this time, the pressure of the fluid is automatically reduced to a predetermined treatment pressure in the treatment tank 11.
A surface of the substrate 100 is supercritically treated with the supercritical carbon dioxide containing the chemical in the treatment tank 11. At this time, the temperature of the fluid in the treatment tank 11 is controlled by the heating device 15 equipped with a temperature controller.
When the pressure in the treatment tank 11 is a predetermined treatment pressure or higher, the first pressure control valve 51 is opened, so that the supercritical carbon dioxide containing the chemical is discharged to the gas-liquid separation-collection device 60 through the heating device 17 and the first pressure control valve 51.
The pressure and temperature in the treatment tank 11 may be kept constant when the supercritical carbon dioxide with which the treatment tank 11 is filled is appropriately discharged in this manner.
A fluid discharged to the gas-liquid separation-collection device 60 from the first pressure control valve 51 and a fluid discharged to the gas-liquid separation-collection device 61 from the second pressure control valve 52 are adiabatically expanded by the pressure control valves 51 and 52, so that a pressure of the fluids is returned to atmospheric pressure. When the pressure of the fluid is returned to atmospheric pressure, the carbon dioxide in a supercritical state is transformed into a gas, so that the fluid may be separated into carbon dioxide gas and a liquid chemical.
The chemical separated from the carbon dioxide is collected in the gas-liquid separation-collection devices 60 and 61 as a discharged liquid. A substance removed or extracted with the supercritical fluid in the treatment tank 11 is dissolved in or accompanied with the chemical and accumulated in the gas-liquid separation-collection device 60.
On the other hand, the carbon dioxide is discharged from the gas-liquid separation-collection devices 60 and 61 as a gas. The discharged carbon dioxide also may be condensed again and collected.
The collected chemical or carbon dioxide also may be reprocessed to be usable and reused.
In the treatment apparatus and the treatment method according to the above-described first embodiment of the present invention, the pressure for mixing a supercritical fluid with a chemical may be optionally determined independently from the treatment apparatus main body 10.
The solubility of the chemical in the supercritical fluid depends on the pressure when the chemical is mixed with the supercritical fluid. Therefore, as the pressure when the chemical is mixed with the supercritical fluid is increased, the solubility of the chemical is increased.
In the above-described treatment apparatus and treatment method, a supercritical fluid may be mixed with a chemical under a high pressure in the mixing tank 40, so that the supercritical fluid may be homogeneously and efficiently mixed with the chemical even when the flow rate of the supercritical fluid is high.
Accordingly, the efficiency in treating a substrate may be improved by increasing the flow rate of the supercritical fluid.
Since the supercritical fluid is mixed with the chemical under a high pressure in a route differing from the treatment tank 11 before supplying the supercritical fluid and the chemical to the treatment apparatus main body 10, a pressure in the treatment tank 11 does not have to be increased to a pressure for treatment or higher. Thus, it is possible to prevent damage to the treatment tank 11 that is caused by allowing the pressure in the treatment tank 11 to be high. Further, since it may not be necessary to increase the pressure in the treatment tank 11 to a pressure for treatment or higher, a normal treatment tank may be used, and a high-pressure proof treatment tank does not have to be used. Thus, the treatment apparatus and method are advantageous in terms of equipment and cost.
As the pressure in the treatment tank 11 is higher, the reactivity of a chemical is higher. Therefore, when the pressure in the treatment tank 11 is increased to a pressure for treatment or higher, the reactivity of the chemical is too high, and treatment, such as etching, is performed even for part of a substrate 100 which may not need such treatment. Accordingly, when the pressure in the treatment tank 11 is high, it is difficult to uniformly treat a substrate.
In contrast, in the above-described method, since the pressure in the treatment tank 11 may not need to be increased to a pressure for treatment or higher, the reactivity of the chemical is not too high. Thus, it is possible to prevent damages to a substrate caused by reaction of the chemical.
Further, the above-described treatment apparatus has the three-way valve 50, so that a fluid supplied from the mixing tank 40 may be optionally switched between the treatment tank 11 and the second pressure control valve 52. Thus, when a supercritical fluid is not homogeneously mixed with a chemical, the three-way valve 50 is switched to the second pressure control valve 52, so that the nonhomogeneous supercritical fluid is not supplied to the treatment tank 11.
Accordingly, it is possible to prevent a substrate from being non-uniformly treated due to a supply of the nonhomogeneous supercritical fluid.
Next, a treatment apparatus according to a second embodiment of the present invention is shown in
The treatment apparatus of
The treatment apparatus main body 10 is formed as a plate-like container and has a treatment tank 11 in which a substrate 100 to be treated is accommodated and treated; and a heating device 15 is incorporated in the treatment tank 11. The main body has heating devices 16 and 17 in front of and behind the treatment tank 11.
A first pressure control valve 51 for controlling the pressure in the treatment apparatus main body 10 and the gas-liquid separation-collection device 60 for separating a fluid discharged from the treatment apparatus main body 10 into carbon dioxide gas and a chemical and to collect the chemical are provided downstream of the treatment apparatus main body 10.
The carbon dioxide supply device 20 is formed of a carbon dioxide cylinder in which pressurized and liquidated carbon dioxide is contained.
An opening-closing valve 24 is provided for the carbon dioxide supply device 20. A pipe 71 is connected to the carbon dioxide supply device 20. The pipe 71 connects the carbon dioxide supply device 20, a cooling device 21 for cooling to liquidize CO2 gas, and a pressurizing device 22 and a heating device 23 for transforming the liquid carbon dioxide into a supercritical state to each other, and is connected to the mixing tank 40.
The pressurizing device 22 is formed of a pressurizing pump or the like, and the heating device 23 is formed of a line heater or the like.
An opening-closing valve 31 is provided for the chemical supply device 30. A pipe 76 is connected to the chemical supply device 30. The pipe 76 is formed so as to be branched to a pipe 76A, a pipe 76B, and a pipe 76C.
The pipe 76A, the pipe 76B, and the pipe 76C have a pressurizing device 34, a pressuring device 35, and a pressurizing device 36, respectively, and have a heating device 37, a heating device 38, and a heating device 39, respectively. The pipes 76A, 76B, and 76C connect the pipe 71 in which supercritical carbon dioxide flows with the pipe 76.
Since supercritical carbon dioxide flowing in the pipe 71 is brought into contact with a chemical flowing in the pipe 76A, the pipe 76B, and the pipe 76C in junctions of the pipe 71 and the pipe 76A, the pipe 76B, and the pipe 76C, the junctions form a mixing device 81A, a mixing device 81B, and a mixing device 81C for mixing the supercritical carbon dioxide with the chemical.
The mixing tank 40 has a solubility observation window 42 for observing whether or not carbon dioxide is mixed with an additive; and a heating device 44 such as a built-in heater is incorporated in an outer wall of the tank.
The pipe 71 into which a fluid mixture of supercritical carbon dioxide with a chemical flows and a pipe 73 from which the fluid is discharged are connected to the mixing tank 40.
The three-way valve 50 is provided between the mixing tank 40 and the treatment apparatus main body 10. The three-way valve 50 is formed to connect the pipe 73 at the side of the mixing tank 40 to a pipe 74 at the side of the treatment apparatus main body 10 and branch a pipe 75 from the pipe 73 and the pipe 74.
The three-way valve 50 is formed so that a supply route of a fluid flowing from the pipe 73 at the side of the mixing tank 40 may be switched between the pipe 74 and the pipe 75.
A second pressure control valve 52 is provided for the pipe 75 divided by the three-way valve 50. The gas-liquid separation-collection device 61 for separating a fluid discharged through the three-way valve 50 and the second pressure control valve 52 into carbon dioxide gas and a chemical and to collect the chemical is provided for the pipe 75.
The second pressure control valve 52 has a configuration in which the valve may control the pressure in the mixing tank 40 and the mixing devices 81A, 81B, and 81C independently from the treatment apparatus main body 10 when the three-way valve 50 blocks the pipe 74 and connects the pipe 73 to the pipe 75.
Next, a method for treating a substrate using the treatment apparatus according to the above-described second embodiment will be described.
First, a substrate 100 to be treated is accommodated in the treatment tank 11 and the cover is closed, so that the treatment tank 111 is sealed.
Then, the first pressure control valve 51 is adequately closed so that the pressure in the treatment tank 11 may be controlled to be a predetermined treatment pressure (26 MPa, for example). The three-way valve 50 is switched so that a fluid from the pipe 73 is supplied to the pipe 74.
Then, the opening-closing valve 24 is opened to supply carbon dioxide from the carbon dioxide supply device 20. The carbon dioxide supplied from the carbon dioxide supply device 20 is cooled using the cooling device 21 and transformed into a liquid state. The carbon dioxide in a liquid state is pressurized to 7.3 MPa or higher by the pressurizing device 22 and heated to 50° C. by the heating device 23 and thus is transformed into a supercritical state.
The carbon dioxide in a supercritical state is introduced into the treatment apparatus main body 10 through the mixing tank 40 and the three-way valve 50. The pressure in the treatment tank 11 is controlled so as to be a pressure for treating the substrate 100 (26 MPa, for example) by the first pressure control valve 51. At this time, when the pressure in the treatment tank 11 is a predetermined pressure or higher, the first pressure control valve 51 is opened, so that the pressure in the treatment tank 11 may be kept constant. The supercritical carbon dioxide discharged from the treatment tank 11 is discharged to the gas-liquid separation-collection device 60 by opening the first pressure control valve 51.
Subsequent treatment of the substrate may be rapidly performed by pre-controlling the pressure in the treatment tank 11 to be a predetermined treatment pressure.
Then, a flow of the supercritical carbon dioxide from the pipe 73 is switched to the pipe 75 from the pipe 74 by the three-way valve 50. Then, the second pressure control valve 52 is adequately closed so that the pressure in the mixing tank 40 may be controlled to be higher than the treatment pressure in the treatment tank 11 (30 MPa, for example).
After a certain time, the pressure in the mixing tank 40 is higher than the treatment pressure in the treatment tank 11 by the supercritical carbon dioxide supplied from the pipe 71.
Then, the opening-closing valve 31 is opened to supply a chemical from the chemical supply device 30.
The chemical supplied from the chemical supply device 30 is divided and flows into the pipe 76A, the pipe 76B, and the pipe 76C from the pipe 76. The chemical is controlled so as to be at a predetermined pressure and temperature by the pressurizing devices 34, 35, and 36 and the heating devices 37, 38, and 39 provided for the respective pipes, and is supplied to the pipe 71. At this time, the chemical is mixed at a ratio of 1 to 5 wt % in total based on the carbon dioxide already heated and pressurized, for example.
The amount of the chemical supplied is determined by the pressurizing devices 34, 35, and 36 so that a concentration of the chemical is decreased from upstream to downstream. For example, 50% of the total amount added is supplied from the pressurizing device 34, 30% of the total amount added is supplied from the pressurizing device 35, and 20% of the total amount added is supplied from the pressurizing device 36.
When the chemical is mixed at a concentration of 5 wt % based on the supercritical carbon dioxide, for example, the chemical is supplied from the pipe 76A at a concentration of 2.5 wt % based on the supercritical carbon dioxide, from the pipe 76B at 1.5 wt % based on the supercritical carbon dioxide, and from the pipe 76C at a concentration of 1 wt % based on the supercritical carbon dioxide.
A method of supplying the chemical to the pipe 71 in the second embodiment will be described.
First, 50% of the total amount of the chemical supplied from the pipe 76 is supplied to the pipe 71 from the pipe 76A by the pressurizing device 34. At this time, the pressurizing devices 35 and 36 are unoperated, and the chemical is not supplied from the pipe 76B and the pipe 76C.
The chemical from the pipe 76A is brought into contact with the supercritical carbon dioxide in the pipe 71 in the mixing device 81A and is supplied to the mixing tank 40 through the pipe 71.
Subsequently, after the chemical supplied from the pipe 76A is stably and homogeneously mixed with the supercritical carbon dioxide, 30% of the total amount of the chemical supplied is supplied to the pipe 71 from the pipe 76B by the pressurizing device 35. At this time, the chemical is continuously supplied from the pipe 76A. The pressurizing device 35 is unoperated, and the chemical is not supplied from the pipe 76C.
The chemical from the pipe 76B is brought into contact with the supercritical carbon dioxide in the mixing device 81B and is supplied to the mixing tank 40 through the pipe 71.
Subsequently, after the chemical supplied from the pipe 76B is stably and homogeneously mixed with the supercritical carbon dioxide, 20% of the total amount of the chemical supplied is supplied to the pipe 71 from the pipe 76C by the pressurizing device 36. At this time, the chemical is continuously supplied from the pipe 76A and the pipe 71B.
The chemical from the pipe 76C is brought into contact with the supercritical carbon dioxide in the mixing device 81C and is supplied to the mixing tank 40 through the pipe 71.
In this manner, the chemical supplied from the chemical supply device 30 and the pipe 76 may be mixed with the supercritical carbon dioxide in the pipe 71 using the pipe 76A, the pipe 76B, and the pipe 76C while changing the concentration of the chemical stepwise.
Thus, excellent solubility may be achieved by mixing the chemical stepwise when it is difficult to dissolve a predetermined concentration of the chemical in the supercritical carbon dioxide at one time.
The chemical supplied from the pipe 76A, the pipe 76B, and the pipe 76C is not homogeneously mixed with the supercritical carbon dioxide for a certain time. Thus, a phase of the supercritical carbon dioxide and a phase of the chemical are separated in the mixing tank 40, and an interface between the two phases may be observed from the solubility observation window 42.
After supplying the chemical from the pipe 76C, the supercritical carbon dioxide and the chemical are discharged to the gas-liquid separation-collection device 61 through the three-way valve 50 and the second pressure control valve 52 until the chemical is stably and homogeneously dissolved.
The chemical is completely dissolved in the supercritical carbon dioxide until the interface between the two phases may not be observed from the solubility observation window 42. The three-way valve 50 is switched to the pipe 74 from the pipe 75, so that a fluid from the mixing tank 40 may be supplied to the treatment tank 11.
The supercritical carbon dioxide in which the chemical is completely dissolved is supplied to the treatment tank 11 from the mixing tank 40 through the pipe 73, the three-way valve 50, the pipe 74, and the heating device 16. At this time, the pressure of the fluid is automatically reduced to a predetermined treatment pressure in the treatment tank 11.
A surface of the substrate 100 is supercritically treated with the supercritical carbon dioxide containing the chemical in the treatment tank 11. At this time, the temperature of the fluid in the treatment tank 11 is controlled by the heating device 15 equipped with a temperature controller.
When the pressure in the treatment tank 11 is a predetermined treatment pressure or higher, the first pressure control valve 51 is opened, so that the supercritical carbon dioxide containing the chemical is discharged to the gas-liquid separation-collection device 60 through the heating device 17 and the first pressure control valve 51.
The pressure and temperature in the treatment tank 11 may be kept constant when the supercritical carbon dioxide with which the treatment tank 11 is filled is appropriately discharged in this manner.
A fluid discharged to the gas-liquid separation-collection device 60 from the first pressure control valve 51 and a fluid discharged to the gas-liquid separation-collection device 61 from the second pressure control valve 52 are adiabatically expanded by the pressure control valves 51 and 52, so that a pressure of the fluids is returned to atmospheric pressure. When the pressure of the fluid is returned to atmospheric pressure, the carbon dioxide in a supercritical state is transformed into a gas, so that the fluid may be separated into carbon dioxide gas and a liquid chemical.
The chemical separated from the carbon dioxide is collected in the gas-liquid separation-collection devices 60 and 61 as a discharged liquid. A substance removed or extracted by the supercritical fluid in the treatment tank 11 is dissolved in or accompanied with the chemical and accumulated in the gas-liquid separation-collection device 60.
On the other hand, the carbon dioxide is discharged from the gas-liquid separation-collection devices 60 and 61 as a gas. The discharged carbon dioxide also may be condensed again and collected.
The collected chemical or carbon dioxide also may be reprocessed so as to be usable and reused.
The treatment apparatus and the treatment method according to the above-described second embodiment may exhibit an effect similar to that exhibited by the treatment apparatus and the treatment method according to the first embodiment.
Further, in the treatment apparatus and the treatment method according to the second embodiment, a chemical to be supplied is divided into multiple portions and then mixed stepwise with supercritical carbon dioxide, so that the chemical may be more homogeneously mixed with the supercritical carbon dioxide.
Therefore, the treatment apparatus and method are advantageous for homogeneously mixing supercritical carbon dioxide with a chemical when efficiency in treating a substrate is improved using a higher flow rate of supercritical carbon dioxide.
In the above-described second embodiment, the pipe 76 is branched to the pipe 76A, the pipe 76B, and the pipe 76C. However, the number of branches is not limited to three. The above effect may be achieved when the number of branches is two or more.
In the first and second embodiments, supercritical carbon dioxide is mixed by a chemical in the mixing tank 40. However, supercritical carbon dioxide may be mixed with a chemical by in-line injection without using the mixing tank 40. When supercritical carbon dioxide is mixed with a chemical by in-line injection, the mixing tank 40 does not have to be used, and the treatment apparatus may have a simplified configuration.
The present invention is not limited to the above-described configuration, and various other configurations are possible without departing from the gist of the present invention.
It should be understood by those skilled in the art that various modifications, combinations, subcombinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| P2006-130494 | May 2006 | JP | national |
