Gas purification device and gas purification method

Abstract

The present invention addresses the problem of providing a gas purification device (100) capable of controllably purifying a laser gas used in a laser generation device (1). A gas purification device (100) for purifying a recovered gas recovered from a laser generating device (1) using a laser gas and supplying the purified gas to the laser generating device (1), the gas purification device (100) being characterized by being provided with: a flow rate control device (MFC) for controlling the flow rate of the recovered gas; a constant-volume supply device (15) that is provided downstream of the flow rate control device (MFC) and supplies an additive gas; and a purifier (16) disposed downstream of the constant volume supply device (15).

Description

Technical Field

[0001] The invention relates to a gas purification device and a gas purification method for a laser device. Background Art

[0002] Laser generating devices such as excimer laser devices are used in photolithography processes in the manufacture of semiconductor devices. If an excimer laser device is used repeatedly, impurities (such as fluorocarbons) will be generated in the laser gas in the laser chamber, and the desired laser output cannot be obtained. In this case, the laser gas needs to be replaced, but since the laser gas contains expensive gas, there are known devices for purifying and reusing the laser gas.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 11-54851

[0006] Patent Document 2: WO2015 / 076415 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In order to stabilize the discharge, the laser gas contains a component (eg, xenon) at a very small concentration of several ppm. The concentration of this component may be less than a predetermined concentration range and needs to be added (supplemented), but it is difficult to control such a small concentration.

[0009] In view of the above problems, an object of the present invention is to provide a gas purification device capable of purifying laser gas used in a laser generator with good controllability.

[0010] Solutions to Solve Problems

[0011] The gas purification device of the present invention is a gas purification device that purifies the recovered gas recovered from a laser generating device using laser gas and supplies the recovered gas to the laser generating device, and is characterized in that:

[0012] The gas purification device comprises:

[0013] A flow control device for controlling the flow of the recycled gas;

[0014] a constant volume supply device, disposed downstream of the flow control device, for supplying an additional gas; and

[0015] A purifier is arranged downstream of the fixed volume supply device.

[0016] By adopting a gas purification device having such a structure, it is possible to provide a gas purification device that can purify gas with good controllability.

[0017] Furthermore, in the gas purification device of the present invention, in the above-mentioned configuration, the fixed volume supply device may supply the added gas discretely.

[0018] By adopting the gas purification device having such a structure, the addition amount can be controlled according to the number of times the addition gas is ejected.

[0019] In addition, the gas purification device of the present invention may also be, in the above structure,

[0020] The fixed volume supply device comprises a fixed volume portion, a first valve and a second valve.

[0021] The first valve and the second valve are located at two ends of the constant volume portion.

[0022] By adopting the fixed volume supply device having such a structure, the amount of added gas can be accurately determined based on the volume of the fixed volume portion determined geometrically.

[0023] In addition, the gas purification device of the present invention may also be, in the above structure,

[0024] The gas purification device comprises:

[0025] A first storage tank disposed upstream of the flow control device; and

[0026] A second storage tank is disposed downstream of the purifier,

[0027] The first storage tank and the second storage tank are connected to each other in a communicable or disconnectable manner.

[0028] By adopting a gas purification device with such a structure, the recovered gas can be purified again, thereby improving the quality assurance of the recovered gas.

[0029] In addition, the gas purification device of the present invention may also be, in the above structure,

[0030] The gas purification device is equipped with a gas analyzer.

[0031] The gas analyzer performs component analysis of the gas in the first storage tank.

[0032] By adopting a gas purification device having such a structure, it is possible to perform quality management of the recovered gas.

[0033] Furthermore, the laser gas purification method of the present invention is characterized in that:

[0034] The laser gas purification method comprises:

[0035] A recovery step of recovering laser gas from the laser generating device;

[0036] A recovered gas analysis step, analyzing the recovered gas and determining whether additional gas needs to be added;

[0037] an adding step, in the recovery gas analysis step, when it is determined that the addition of the added gas is required, adding the added gas by a fixed volume supply device;

[0038] A purification step, purifying the recovered gas;

[0039] a purified gas analysis step of analyzing the components of the recovered gas purified by the purification step and determining whether further purification is required; and

[0040] The re-purification step is performed when it is determined in the purified gas analysis step that re-purification is necessary.

[0041] By adopting a gas purification method with such a structure, it is possible to improve the accurate control, quality management, and assurance of the components of the recovered gas.

[0042] Effects of the Invention

[0043] According to the present invention, it is possible to provide a gas purification device capable of purifying laser gas used in a laser generator with good controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The main components of the gas purification device 100 are schematically shown.

[0045] Figure 2 Represents the purification process of the gas recovered from the laser chamber.

[0046] Figure 3 is a cross-sectional view showing the main structure of the gas supply control device 15, Figure 3 (A) is a cross-sectional view showing the connection relationship of the gas supply control device 15 in the gas purification device 100, Figure 3 (B), (C), and (D) are cross-sectional views showing the operation of the gas supply control device 15 .

[0047] Figure 4 The following is a non-limiting example of the configuration of the purifier 16. Figure 4 (A) shows an example of a structure having a first purifier 16a, a second purifier 16b and a third purifier 16c, Figure 4 (B) shows an example of a configuration including a first purifier 16a, a second purifier 16b, a third purifier 16c, and a fourth purifier 16d. DETAILED DESCRIPTION

[0048] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. However, the following embodiments are not to be interpreted restrictively in the determination of the gist of the present invention. In addition, the same or similar components are marked with the same reference numerals, and the description is sometimes omitted.

[0049] Furthermore, terms such as "parallel", "orthogonal", "same", "vertical", "horizontal", etc., or values ​​of lengths and angles (directions) used in this specification to determine shapes, geometric conditions and their degrees are not strictly limited in meaning and are interpreted within the scope of the degree to which the same function can be expected.

[0050] (Implementation Method 1)

[0051] Hereinafter, an example of an embodiment of the gas purification device 100 will be described with reference to the drawings.

[0052] Figure 1 The main components of the gas purification device 100 are schematically shown. Figure 1 As shown, the gas purification device 100 is connected to the laser chamber of the excimer laser generator 1 via a pipe 10 (recovery pipe) and a pipe 20 (supply pipe). The pipe 10 and the pipe 20 are connected via a pipe 30 (main pipe).

[0053] Furthermore, the number of excimer laser generators 1 connected to one gas purification device 100 is not necessarily limited to one, and a plurality of excimer laser generators 1 may be connected to one gas purification device.

[0054] The gas purification device 100 includes a first tank 2, a first pump 3, a second tank 4, a second pump 5, a third tank 6, a fourth tank 7, a third pump 8, and a fifth tank 9 in order from the pipe 10 side. A purifier 16 (impurity removal device) is provided between the third tank 6 and the fourth tank 7. The purifier 16 removes impurities (such as CF 4 , oxygen, water, etc.).

[0055] These components are connected via pipes 30 .

[0056] The first tank 2 communicates with the laser chamber via a pipe 10 , and the fifth tank 9 communicates with the laser chamber via a pipe 20 .

[0057] Laser gas for generating laser light is recovered from the laser chamber of the laser generating device 1 to the gas purification device 100 via the pipe 10, and after purification, is returned from the gas purification device 100 to the laser chamber via the pipe 20. Hereinafter, the pipe 10 side may be referred to as the upstream, and the pipe 20 side may be referred to as the downstream.

[0058] The laser generating device 1 can be a known device and has a laser chamber filled with laser gas. As the laser gas, a known laser gas is used, and as a non-limiting example, neon (Ne), halogen gas (F 2 The laser gas is a mixed gas of other rare gases (xenon (Xe), krypton (Kr), argon (Ar), etc.), and the filling pressure is usually about 200 to 600 kPa. The component ratio (mixing ratio) of the laser gas can adopt a known ratio.

[0059] The gas purification device 100 includes a control device 12, which can control the opening and closing of each valve provided on the piping, and can also control the operation and stop of the first pump 3, the second pump 5, and the third pump 8 based on a predetermined pressure. In addition, these first, second, and third pumps may be configured to be autonomously driven while detecting pressure without depending on the control device 12, or may be configured to take into account both autonomous driving and control by the control device 12.

[0060] Each tank may have a pressure gauge, and each pressure gauge may measure the pressure of the gas in each tank. The control device 12 can input the value of each pressure gauge and monitor the pressure of the gas in each tank.

[0061] In addition, the measurement result of the gas analyzer 11 provided in the gas purification device 100 is input to the control device 12 .

[0062] Hereinafter, the purification operation of the laser gas by the gas purification device 100 will be described in detail. Figure 2 Represents the purification process of the gas recovered from the laser chamber.

[0063] When receiving a request for purification of the gas exhausted from the laser generator 1 , the control device 12 executes the purification flow described below.

[0064] In addition, the control device 12 can communicate with each valve and each pump through wireless or wired communication means, and in each step, the opening and closing control of each valve and the driving and stopping control of each pump are performed by the control device 12.

[0065] In the following description, valves not specifically described are in a closed state.

[0066] Step 1 (gas recovery step)

[0067] The valves V1 and V2 located upstream and downstream of the first tank 2 and the valve V3 located downstream of the first pump 3 are set to an open state, and the gas recovered from the laser generating device 1 (laser chamber) (hereinafter referred to as recovered gas) is introduced into the first tank 2 (recovery tank) via the piping 10 (recovery piping), and is pressure-transmitted to the second tank 4 (first storage tank) through the first pump 3.

[0068] When the recovered gas stored in the second tank 4 reaches a predetermined pressure (storage pressure), for example, a pressure not limited to 100 kPa and not more than 400 kPa, the valve V3 is closed, the first pump 3 is stopped, and the process proceeds to step 2 .

[0069] Step 2 (gas pressurization step)

[0070] The valve V3 is set to a closed state, and the valves V4 and V5 upstream and downstream of the second pump 5 are set to an open state. The recovered gas in the second tank 4 is pressure-sent to the third tank 6 (boosting tank) by the second pump 5, and the pressure in the third tank 6 is increased.

[0071] A pressure gauge G6 is provided on the third tank 6, and the pressure gauge G6 measures the gas pressure in the third tank 6. The control device 12 obtains the measured value P6 of the pressure gauge G6, and if it is determined that a predetermined threshold value Pt1 (e.g., 600 kPa to 900 kPa) (P6 ≥ Pt1) has been reached, the valve V5 is set to a closed state, the second pump 5 is stopped, and the process is transferred to step 3.

[0072] If the increase in the pressure of the third tank 6 is saturated and does not reach the predetermined threshold, the process returns to step 1. The control device 12 repeats steps 1 and 2 until the pressure of the third tank 6 reaches the predetermined threshold.

[0073] In addition, as the second pump 5, a pump that can be driven in a wide area (wide pressure range) can also be used, and the first tank 2, the first pump 3, the valve V1 and the valve V2 are not required. In this case, the step (gas recovery and pressure increase step) formed by integrating step 1 and step 2 is executed. Specifically, valves V3, V4, and V5 can be set to an open state, and valve V6 can be set to a closed state, and the recovered gas can be pressed to the third tank 6 by the second pump 5. When it is determined that the measured value P6 of the gas pressure in the third tank 6 reaches the threshold value Pt1 (Pt above P6), the control device 12 sets valves V3 and valve V to a closed state, stops the second pump 5, and transfers to step 3.

[0074] Step 3 (recovered gas analysis step)

[0075] The valve V5 and the valve V6 downstream of the third tank 6 are set to a closed state, and the valve VA1 provided on the pipe A1 connecting the third tank 6 and the gas analyzer 11 is set to an open state, and the concentration of the components of the recovered gas in the third tank 6 is measured by the gas analyzer 11. The output of the gas analyzer 11 is output to the control device 12. As the gas analyzer 11, for example, a mass analyzer can be used.

[0076] The control device 12 determines whether the concentration of the components constituting the laser gas (eg, neon, krypton, xenon, argon, etc.) is within a predetermined concentration range for each measured component, and determines whether the addition of the additive gas is necessary.

[0077] The control device 12 determines that the component having a concentration lower than the predetermined concentration range needs to be added (supplemented), calculates the addition amount (doping amount) of the additive gas so that the component is included in the predetermined concentration range, and moves to step 4.

[0078] For example, the gas analyzer 11 measures the xenon concentration of the recovered gas. When it is determined that the xenon concentration is lower than a predetermined concentration, the control device 12 determines that xenon needs to be added (supplemented), and calculates the amount of xenon to be added (doped) to the recovered gas so that the xenon concentration is within a predetermined concentration range. Then, the process proceeds to step 4.

[0079] When it is determined that all the constituent components do not need to be added, the process proceeds to step 5 .

[0080] Step 4 (Adding Process)

[0081] When the valve V5 and the valve V8 downstream of the fourth tank 7 (the second storage tank) are closed, and the valve V6 and the valve V7 upstream of the fourth tank 7 are opened, the recovery gas accumulated in the third tank 6 is made to flow to the downstream pipe 30 in a state where the third tank 6 and the fourth tank 7 are connected. The recovery gas is adjusted to a predetermined pressure (PG1) by the pressure regulator RG1, and the flow rate is controlled by the flow control device (mass flow controller) MFC provided downstream of the pressure regulator RG1.

[0082] The gas cylinder 14 filled with the additive gas is connected to the pipe 31 (addition pipe), and the pipe 31 is connected to the pipe 30 downstream of the flow control device MFC.

[0083] A pressure regulator RG2 (RG2a, RG2b) and a gas supply control device 15 (fixed volume supply device) described later are provided on the piping 31. The added gas in the gas cylinder 14 is adjusted to a specified pressure (PG2) by the pressure regulator RG2 and flows into the gas supply control device 15.

[0084] The control device 12 controls the gas supply control device 15 based on the calculated addition amount to make the added gas (such as xenon, argon, etc.) flow from the gas cylinder 14 to the pipe 31. At the connection point between the pipe 31 and the pipe 30, the recovered gas and the added gas merge.

[0085] Furthermore, in order to add a component at a minute concentration, for example, xenon, xenon gas diluted with neon (mixed gas of neon and xenon) may be used.

[0086] In addition, when supplying multiple, for example, two, additional gases, the gas cylinder 14 may also have a first gas cylinder 14a and a second gas cylinder 14b, and the first gas cylinder 14a and the second gas cylinder 14b are respectively connected to the piping 31a, 31b, and pressure regulators RG2a, RG2b and gas supply control devices 15a, 15b are respectively provided on the piping 31a, 31b to control the addition amount of each additional gas.

[0087] Figure 1 An example is shown which includes a first gas cylinder 14a and a second gas cylinder 14b.

[0088] As described later, the gas supply control device 15 is a fixed volume supply device, which makes a predetermined volume of the added gas flow out to the pipe 30 through the pipe 31 through one ejection action, and controls the volume of the required amount of the added gas by performing the ejection action a predetermined number of times. That is, the gas supply control device 15 discretely supplies a predetermined volume of gas.

[0089] Since the volume of the recovered gas flowing through the pipe 30 per unit time is determined by the flow control device MFC, the control device 12 can calculate the amount of added gas (supplementary amount) per unit time and the number of injections per unit time. Therefore, the necessary amount of added gas can be added to the recovered gas.

[0090] In addition, the pipe 30 may include a mixer 13 downstream of the communicating portion with the pipe 31. In the mixer 13, the uniformity of mixing of the added gas and the recovered gas is improved.

[0091] The mixed gas to which the additional gas is added is subjected to the purification process of step 5 .

[0092] Since the flowing recovered gas is continuously processed in step 4 and step 5, the gas purification device 100 performs step 4 and step 5 simultaneously.

[0093] In addition, it is also preferable to keep the temperature constant by covering the entirety with the frame 40. In particular, by maintaining the flow control device MFC and the gas supply control device 15 at the same temperature, it is possible to perform more stable addition amount control.

[0094] Step 5 (Purification Step)

[0095] The valves V6 and V7 are opened, and the mixed gas of the recovered gas and the added gas is introduced into the purifier 16 through the pipe 30 , and is purified by the purifier 16 .

[0096] When it is determined in step 3 that the addition of gas is unnecessary, the recovery gas is purified by the purifier 16 instead of the mixed gas.

[0097] Hereinafter, the expression "mixed gas" means "recovered gas" when it is determined in step 3 that the addition of gas is not necessary.

[0098] In addition, the purifier 16 can also be non-limitingly Figure 4 As shown, there are multiple purifiers.

[0099] Figure 4 The following is a non-limiting example of the structure of the purifier 16. Figure 4 (A) shows an example of a structure having a first purifier 16a, a second purifier 16b and a third purifier 16c, Figure 4 (B) shows an example of a configuration including a first purifier 16a, a second purifier 16b, a third purifier 16c, and a fourth purifier 16d.

[0100] For example, in Figure 4 In the example shown in (A), the first purifier 16a has a function of removing carbon fluoride (CF 4 The second purifier 16b has a purifier for removing water, the third purifier 16c has a purifier for removing oxygen, and in addition, Figure 4 In the example shown in (B), a purifier (getter) for removing impurities that have not been completely removed, namely a fourth purifier 16d, is further provided. Depending on the purpose of the laser gas used, for example, for KrF laser or ArF laser, the purifier can be selected separately. Figure 4 (A) or Figure 4 (B) Structure: Each purifier uses a known purifier and can be operated under known conditions.

[0101] The structure of the purifier 16 is not limited to the above, and any purifier required to maintain the quality of the laser gas can be adopted.

[0102] The mixed gas purified by the purifier 16 is accumulated in the fourth tank 7, and the pressure in the fourth tank 7 increases. On the other hand, the pressure P6 of the gas in the third tank 6 decreases, and when it reaches or exceeds a predetermined threshold value Pt2 (for example, a value 100 kPa to 200 kPa lower than Pt1) (P6 ≤ Pt2), valves V6 and V7 are closed, the purification step is terminated, and the process is transferred to step 6.

[0103] In addition, the purifier 16 generally uses a catalyst or adsorbent in contact with the gas to remove impurities in the gas, so the mixed gas passes through the purifier 16, thereby further improving the uniformity of mixing the recovered gas and the added gas. In addition, since the mixed gas is accumulated in the fourth tank 7, the uniformity of mixing the recovered gas and the added gas in the fourth tank 7 is further improved.

[0104] As described above, the gas supply control device 15 discretely supplies the added gas, but the purifier 16 and the fourth tank 7 have the effect of further improving the uniformity of mixing.

[0105] Step 6 (Purified Gas Analysis Step)

[0106] When valves V7 and V8 are closed, valve VA2 of piping A2 connecting the fourth tank 7 and the gas analyzer 11 is opened, and the recovered gas (mixed gas) accumulated in the fourth tank 7 is subjected to component analysis (impurity analysis) by the gas analyzer 11.

[0107] The output from the gas analyzer 11 is input to the control device 12, and the concentration of each component and the concentration of other impurities can be calculated.

[0108] After the component analysis is completed, the valve VA2 is closed.

[0109] The control device 12 compares the measured impurity concentration with the judgment value, and determines that re-purification is necessary when the impurity concentration is greater than the judgment value, and determines that re-purification is not necessary when the impurity concentration is less than the judgment value.

[0110] When the control device 12 determines that re-purification is necessary, the process proceeds to step 7 .

[0111] When the control device 12 determines that re-purification is not necessary, the process proceeds to step 8 .

[0112] In addition, the determination value is determined by the range in which the laser generator 1 can operate normally.

[0113] In this way, by accumulating the purified mixed gas (recovery gas) in the fourth tank 7 and analyzing the components, the quality management of the mixed gas can be performed.

[0114] In addition, the concentration of each component (additional gas) of the mixed gas may be analyzed (measured) in step 6. If the concentration of the addition gas does not reach the predetermined range, step 7 may be executed, and the process may be transferred to step 4 and then to step 5 for re-addition.

[0115] Step 7 (re-purification step)

[0116] The valves V3 and V6 are closed, the valves VB, V4, and V5 are opened, and the recovered gas accumulated in the fourth tank 7 is guided to the second tank 4 via the pipe B (bypass pipe), and is pressure-sent to the third tank 6 by the second pump 5. The mixed gas is accumulated in the third tank 6.

[0117] When the pressure P6 of the third tank 6 reaches a predetermined pressure Pt3 (for example, the same value as Pt1) (P6 ≥ Pt3), the control device 12 closes the valve VF and the valves V4 and V5.

[0118] When it is determined that the recovered gas needs to be re-purified, the fourth tank 7 and the second tank 4 are connected via the pipe B in this step 7 to enable the movement of the recovered gas. In other steps, the movement of the recovered gas is blocked by the valve VB.

[0119] Then, move to step 5.

[0120] As described above, the fourth tank 7 and the second tank 4 are connected via the pipe B and the valve VB in a manner that allows selective communication or interruption, based on the result of the gas analysis in step 6 .

[0121] Here, “communication” refers to a state in which the valve VB is open and gas can flow, and “blocking” refers to a state in which the valve VB is closed and gas flow is blocked.

[0122] Step 8 (Purification Gas Supply Step)

[0123] In step 6, when it is determined that repurification is not necessary, the valve V10 located downstream of the fifth tank 9 (supply tank) is closed and the valves V8 and V9 located upstream and downstream of the third pump 8 are opened, and the mixed gas accumulated in the fourth tank 7 is pressure-fed to the fifth tank 9 by the third pump 8. The mixed gas is accumulated in the fifth tank 9.

[0124] When the pressure P9 of the mixed gas in the fifth tank 9 reaches a predetermined pressure Pt4 (for example, the same as Pt1) (P9 ≥ Pt4), the valves V8 and V9 are closed.

[0125] Then, the valve V10 is opened, and the mixed gas stored in the fifth tank 9 is supplied to the laser generator 1 through the second pipe 20 (supply pipe).

[0126] In addition, the components of the mixed gas stored in the fifth tank 9 may be analyzed by the gas analyzer 11 before the valve V10 is opened.

[0127] In this case, valves V10 and V9 are closed, valve VA3 of pipe A3 connecting the fifth tank 9 and gas analyzer 11 is opened, and the gas analyzer 11 is used to analyze the components of the mixed gas in the fifth tank 9. This helps to manage and ensure the quality of the recovered gas after purification.

[0128] Through the above steps, the recovered gas is purified and supplemented with additional gas to recirculate the laser gas, which can contribute to reducing the operating cost of the laser generator 1 .

[0129] In addition, a plurality of third tanks 6 may be provided and used alternately.

[0130] For example, two third tanks 6A and 6B may be provided, and steps 1 and 2 may be performed in the third tank 6A on one side, and then while performing the steps after step 3, steps 1 and 2 may be performed in the third tank 6B on the other side, and the recovered gas may be accumulated and pressurized in the third tank 6B.

[0131] After the third tank 6A on one side completes step 10 or is in the process of executing step 10 , the third tank 6B on the other side can execute the steps after step 3 .

[0132] By alternately using a plurality of third tanks 6 , it is possible to contribute to improving the utilization efficiency of the gas purification device 100 .

[0133] In addition, a plurality of purifiers 16 may be arranged in parallel and used alternately. For example, the second purifier 16b may be a purifier for absorbing water, and the third purifier 16c may be a purifier for absorbing oxygen, and two of each of the second purifiers 16b and 16b' and the third purifiers 16c and 16c' may be connected in parallel, and purification operations and purifier regeneration operations may be performed alternately in parallel.

[0134] By performing purification of the recovered gas using one purifier 16 (e.g., the second purifier 16b and the third purifier 16c) and regenerating the other purifier 16 (e.g., the second purifier 16b' and the third purifier 16c'), the gas purification device 100 can continue to perform purification operation without stopping operation for regeneration of the purifier 16.

[0135] For example, when the second purifier 16b is set as a purifier for adsorbing water and the second purifier 16b is regenerated, the second purifier 16b is evacuated by a vacuum pump (not shown) to discharge the adsorbed substances in the second purifier 16b, and then laser gas is supplied from a gas cylinder (not shown) to the second purifier 16b to fill the second purifier 16b with laser gas.

[0136] For example, in the piping 30 connected to the second purifier 16b, valves are provided on the upstream and downstream sides of the second purifier 16b, and these valves are closed. A vacuum pump is connected to the piping 30 between the second purifier 16b and the upstream valve, the second purifier 16b is evacuated, and then a purge gas (for example, argon) is supplied to the second purifier 16b from the piping 30 between the second purifier 16b and the downstream valve. Then, the supply of the purge gas may be stopped, and after the second purifier 16b is evacuated, the vacuum pump is stopped, and the laser gas is filled into the second purifier 16b from the piping 30 between the second purifier 16b and the downstream valve. The same is true for the third purifier 16c (for example, a purifier that absorbs oxygen).

[0137] Hereinafter, the gas supply control device 15 as a fixed volume supply device for gas will be described in detail with reference to the drawings. The fixed volume supply device is a device that supplies a predetermined volume of gas in one operation (discharge).

[0138] Figure 3 It is a cross-sectional view showing the main structure of the gas supply control device 15 . Figure 3 (A) is a cross-sectional view showing the connection relationship of the gas supply control device 15 in the gas purification device 100, Figure 3 (B), (C), and (D) are cross-sectional views showing the operation of the gas supply control device 15 .

[0139] The gas supply control device 15 includes an inlet 151, an outlet 152, an inlet path 153, a constant volume unit 154 (accommodation area), an outlet path 155, a first valve 156 (inlet valve), and a second valve 157 (outlet valve). The first valve 156 and the second valve 157 are located at both ends of the constant volume unit 154.

[0140] The first valve 156 has a first valve body 156 a and a first valve seat 156 b , and the second valve 157 has a second valve body 157 a and a second valve seat 157 b .

[0141] When the first valve body 156a and the first valve seat 156b are separated, the first valve 156 is in an open state, and when the first valve body 156a and the first valve seat 156b are in contact, the first valve 156 is in a closed state. Similarly, when the second valve body 157a and the second valve seat 157b are separated, the second valve 157 is in an open state, and when the second valve body 157a and the second valve seat 157b are in contact, the second valve 157 is in a closed state.

[0142] In addition, a known structure can be used as the valve to be operated. For example, a diaphragm or the like can be used as the valve body without limitation, and the valve can be operated by an air (gas) drive method using compressed air or the like, or an electromagnetic drive method using an electromagnet or the like.

[0143] The inlet 151 is connected to the gas cylinder 14 via the pipe 31 (addition pipe), and the outlet 152 is connected to the pipe 31 .

[0144] The additional gas in the gas cylinder 14 is supplied to the gas supply control device 15 via the pressure regulator RG2. The pressure regulator RG2 adjusts the additional gas to a pressure higher by a predetermined amount Pd (eg, 100 kPa) than the pressure (PG1) of the recovery gas set by the pressure regulator RG1 of the pipe 30 (PG2=PG1+Pd).

[0145] The added gas flowing out from the outlet 152 of the gas supply control device 15 flows into the pipe 30 via the pipe 31 .

[0146] Reference Figure 3 (B), (C), and (D) describe the gas supply operation by the gas supply control device 15.

[0147] To supply the gas, the ejection (injection) has the following steps.

[0148] Step 1 (Inflow Step)

[0149] like Figure 3 As shown in FIG. 2B , the second valve 157 is closed and the first valve 156 is opened. As shown by arrows in the figure, the added gas pressure-regulated by the pressure regulator RG2 flows into the constant accumulation section 154 through the inlet 151 , the inflow path 153 and the first valve 156 .

[0150] Step 2 (Containment Step)

[0151] like Figure 3 As shown in (C), the first valve 156 is set to a closed state, and the second valve 157 is set to a closed state.

[0152] In the fixed volume section 154, the added gas is sealed by the first valve 156 and the second valve 157. The sealed added gas has the volume of the fixed volume section 154 and the pressure PG2 (accommodation pressure) adjusted by the pressure regulator RG2. The added amount is determined according to the gas accommodated in the fixed volume section 154. A predetermined volume of gas can be delivered by one ejection.

[0153] The volume (capacity) of the constant volume portion 154 can be determined geometrically, and for the purpose of minute amount control, can be set to, for example, 0.1 to 1 cc without limitation, but is not limited thereto.

[0154] Through this step, the added gas is quantitatively added.

[0155] Step 3 (Outflow Step)

[0156] like Figure 3As shown in (D), the first valve 156 is kept closed and the second valve 157 is opened. The pressure PG2 of the added gas contained in the constant volume section 154 is higher than the pressure PG1 of the recovered gas in the piping 30, so it flows out of the gas supply control device 15 through the second valve 157, the outflow path 155 and the outflow port 152 and flows into the piping 30.

[0157] The amount of added gas ejected at one time can be controlled by the volume and pressure of the fixed volume unit 154. By setting the volume of the fixed volume unit 154 according to the amount (volume) of added gas to be controlled, it is also possible to achieve control of a minute amount.

[0158] By controlling the number of injections, the amount of added gas can be adjusted, and a necessary amount of added gas can be mixed into the recovered gas. The number of injections per unit time is calculated by the control device 12 based on the component concentration of the recovered gas and the target component concentration. The control device 12 controls the number of injections per unit time by controlling the opening and closing of the first valve 156 and the second valve 157.

[0159] The control device 12 digitally controls the opening and closing of the first valve 156 and the second valve 157, and the constant volume supply device discharges the gas discretely (in pulses).

[0160] In the past, the added gas was controlled by a flow control device as a flow control device, specifically a mass flow controller, through a continuous amount of gas flow. However, a mass flow controller requires a limited time until the flow rate stabilizes, and it is difficult to accurately control a small amount of doping. In addition, a mass flow controller has a small amount of residual gas in the space (useless space) between the flow control part and the on-off valve arranged downstream thereof. Since the residual gas exists downstream of the flow control part, flow control cannot be performed, and it is difficult to accurately control the amount of addition. That is, in the flow control using the previous mass flow controller, it is difficult to accurately control the supply amount of the small amount of added gas supplied from the gas cylinder 14.

[0161] On the other hand, since the gas supply control device 15 determines the addition of gas through the constant volume portion 154 separated by two valves, there is no useless space like a mass flow controller, and a limited time for stabilizing the flow rate is not required. Therefore, the gas supply control device 15 is excellent in controlling a small amount of addition.

[0162] In addition, the gas supply control device 15 can be used not only to add gas during the purification process of the recovered gas, but also to supply laser gas when the laser generator 1 is started. Since the amount of added gas can be controlled, it can also be used to generate laser gas with an optimal component concentration and fill it into the laser chamber.

[0163] By generating the laser gas and removing impurities through the purifier 16 , it is possible to fill the laser chamber with a laser gas having a higher purity.

[0164] Industrial Applicability

[0165] According to the present invention, the amount of added gas added to the laser gas used in the laser generating device can be accurately controlled, and the impurity removal performance of the recovered gas can be improved by enabling repurification, so that high-quality recovered gas can be supplied. By recycling the laser gas, the operating cost of the laser generating device can be reduced, and the possibility of industrial application is high.

[0166] Description of Reference Numerals

[0167] 100 Gas Purification Device

[0168] 1Laser generating device

[0169] 2First can (recycling can)

[0170] 3. First pump (recovery pump)

[0171] 4Second tank (first storage tank)

[0172] 5. Second pump (boost pump)

[0173] 6Third tank (boost tank)

[0174] 7The fourth tank (the second storage tank)

[0175] 8Third pump (supply pump)

[0176] 9Fifth tank (supply tank)

[0177] 10 Piping (recovery piping)

[0178] 11Gas Analyzer

[0179] 12 Control Devices

[0180] 13. Mixer

[0181] 14 Gas Cylinders

[0182] 14a First gas cylinder

[0183] 14b Second gas tank

[0184] 15, 15a, 15b Gas supply control device (fixed volume supply device)

[0185] 151 Inlet

[0186] 152 Flow outlet

[0187] 153 Inflow Road

[0188] 154 Fixed Volume Department (Accommodation Area)

[0189] 155 Outflow Road

[0190] 156 First valve (inflow valve)

[0191] 156a First valve body

[0192] 156b First valve seat

[0193] 157 Second valve (outflow valve)

[0194] 157a Second valve body

[0195] 157b Second valve seat

[0196] 16 Purifier (impurity removal device)

[0197] 16a The first purifier (impurity removal device)

[0198] 16b Second Purifier (Impurity Removal Device)

[0199] 16c The third purifier (impurity removal device)

[0200] 16d Fourth Purifier (Impurity Removal Device)

[0201] 20 Piping (supply piping)

[0202] 30 piping (main piping)

[0203] 31, 31a, 31b piping (additional piping)

[0204] 40 frame

[0205] A1 piping

[0206] A2 Piping

[0207] B piping (bypass piping)

[0208] MFC flow control device (mass flow controller)

[0209] G6 Pressure Gauge

[0210] RG1 Pressure Regulator

[0211] RG2, RG2a, RG2b pressure regulator

[0212] V1~V10 valve

[0213] VA1, VA2 valves

Claims

1. A gas purification device for purifying recovered gas recovered from a laser generating device using laser gas and supplying the recovered gas to the laser generating device, characterized in that: The gas purification device comprises: A flow control device for controlling the flow of the recycled gas; a constant volume supply device, disposed downstream of the flow control device, for supplying an additional gas; and A purifier is arranged downstream of the fixed volume supply device.

2. The gas purification device according to claim 1, characterized in that: The fixed volume supply device supplies the additional gas discretely.

3. The gas purification device according to claim 2, characterized in that: The fixed volume supply device comprises a fixed volume portion, a first valve and a second valve. The first valve and the second valve are located at two ends of the constant volume portion.

4. The gas purification device according to any one of claims 1 to 3, characterized in that: The gas purification device comprises: A first storage tank disposed upstream of the flow control device; and A second storage tank is disposed downstream of the purifier, The first storage tank and the second storage tank are connected to each other in a communicable or disconnectable manner.

5. The gas purification device according to claim 4, characterized in that: The gas purification device is equipped with a gas analyzer. The gas analyzer performs component analysis of the gas in the first storage tank.

6. A method for purifying laser gas, characterized in that: The laser gas purification method comprises: A recovery step of recovering laser gas from the laser generating device; A recovered gas analysis step, analyzing the recovered gas and determining whether additional gas needs to be added; an adding step, in the recovery gas analysis step, when it is determined that the addition of the added gas is required, adding the added gas by a fixed volume supply device; A purification step for purifying the recovered gas; a purified gas analysis step of analyzing the components of the recovered gas purified by the purification step and determining whether further purification is required; and The re-purification step is performed when it is determined in the purified gas analysis step that re-purification is necessary.

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