JP2009266888A - Etching apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an etching apparatus capable of reducing consumption of a reactive gas. <P>SOLUTION: The etching apparatus supplies xenon difluoride gas prepared by evaporating solid xenon difluoride in a cylinder 15 to an etching chamber 11 and etches a sample W conveyed into the chamber 11. The etching apparatus includes a stage 21 for partitioning a processing space 22 movably carried in the etching chamber 11 for etching the sample W and a reservoir space 23 for temporarily reserving the xenon difluoride gas supplied to the processing space 22 and also allowing no xenon difluoride gas to flow between the processing space 22 and the reservoir space 23. The apparatus further includes a pipe 45 having a valve 45a for connecting between the processing space 22 and the reservoir space 23 and a controller 16 for controlling the valve 45a to open/close to supply the gas to the processing space 22. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an etching apparatus for etching a sample with a gas.

Conventionally, in a manufacturing process of a semiconductor integrated circuit device, a sensor chip, a MEMS (Micro Electro Mechanical Systems) device, etc., xenon difluoride gas (XeF ₂ ) or the like is used to etch a target portion (silicon, molybdenum, etc.) of a sample. A reactive gas is used. Usually, xenon difluoride is supplied in the form of colorless crystals. The etching apparatus gasifies the crystalline xenon difluoride and supplies it to the etching chamber. Patent Document 1 discloses an etching apparatus that continuously supplies sublimated xenon difluoride gas to an etching chamber in order to improve the processing capacity of the apparatus.

  In this etching apparatus, since the gas stays in the etching chamber for a short time, xenon difluoride gas that does not react with the object is discharged from the etching chamber. That is, in this apparatus, xenon difluoride gas is wasted. It will be. Since xenon difluoride crystals are relatively expensive, they are problematic.

For example, Patent Document 2 has two expansion chambers for the above-described problem, and while supplying gas from one expansion chamber to the etching chamber, the other expansion chamber is filled with sublimated gas. An etching apparatus that efficiently supplies gas is disclosed. Patent Document 2 discloses an etching apparatus that has a variable volume expansion chamber and supplies xenon difluoride gas to the etching chamber at a high pressure by a process of denting the variable volume expansion chamber.
Japanese Patent Laid-Open No. 10-317169 JP-T-2004-525253

  By the way, when the etching process is performed, a reaction product is generated around the sample, and it becomes difficult for the xenon difluoride gas to react with the sample. Therefore, as in Patent Document 2, the etching process is efficiently performed by discharging the gas in the etching chamber after a predetermined time and supplying the xenon difluoride gas again. However, since the exhausted gas contains unreacted xenon difluoride gas, a part of the xenon difluoride gas supplied to the etching chamber is wasted. In addition, such a problem has become remarkable since the xenon difluoride gas supplied at a time is increasing with the increase in the size of the etching chamber due to the increase in the size of the sample in recent years. .

  Therefore, it is conceivable to reduce the amount of gas discharged by reducing the capacity of the etching chamber. However, since the sample is generally carried from the outside by a transfer device, a space where the transfer device can enter the etching chamber must be secured, and the volume of the etching chamber is reduced to reduce the consumption of xenon difluoride gas. It was difficult to suppress.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an etching apparatus capable of suppressing the consumption of reactive gas.

  In order to solve the above-mentioned problems, an invention according to claim 1 is an etching apparatus for supplying a gas obtained by vaporizing a raw material in a gas supply source to an etching chamber and etching a sample carried into the etching chamber. The etching chamber is movably supported, and the etching chamber is partitioned into a processing space for etching the sample and a storage space for temporarily storing the gas supplied to the processing space, and the processing space. And a stage for disabling the gas between the storage space, a pipe communicating the processing space and the storage space, and a valve provided in the pipe to control opening and closing of the gas. And a control device for supplying to.

  According to this configuration, the etching chamber is partitioned into a processing space in which the sample is etched by moving the stage and a storage space for temporarily storing the gas supplied to the processing space. Gas is not allowed to flow to and from the space. Etching is performed in the processing space by supplying gas from the storage space via the pipe. Therefore, the capacity of the processing space for etching the sample can be reduced while ensuring a space in which the transfer device can enter the etching chamber. Thereby, the quantity of the xenon difluoride discharged | emitted without reacting can be decreased, and the consumption of reactive gas can be suppressed. Further, since the storage space can function as a buffer, the number of parts of the etching apparatus can be reduced as compared with a case where a separate buffer is provided.

  According to a second aspect of the present invention, in the etching apparatus according to the first aspect, the etching chamber and the gas supply source are connected to each other via a pipe having a valve that is controlled to be opened and closed by the control device. It has a buffer set to a capacity larger than the space capacity. According to this configuration, the buffer and the storage space are connected in series. Since the capacity of the buffer is set larger than the capacity of the processing space, when gas is supplied from the gas supply source to the buffer after the gas is supplied from the buffer to the storage space, the amount supplied to the storage space is reduced. Since only the gas needs to be supplied to the buffer, the supply time of the gas vaporized from the raw material can be shortened.

  According to a third aspect of the present invention, in the etching apparatus according to the first or second aspect, the etching chamber has a first opening that opens upward, and the stage is movable in the vertical direction inside. And a second chamber having a second opening smaller than the first opening, the first opening and the second opening being opposed to each other, wherein the stage includes the first chamber The processing space is partitioned by the second chamber and the stage in a state where the opening is closed and the stage is in contact with the opening end of the second chamber and the second opening is closed. To be formed. According to this configuration, the plate-shaped stage is brought into contact with the opening end of the first chamber so that the first opening is closed and the processing space is partitioned. For example, a sample is placed on the stage. It is not necessary to make the stage and the first and second chambers complicated shapes, such as by forming concave portions, and the etching apparatus can have a simple configuration.

  Invention of Claim 4 is an etching apparatus as described in any one of Claims 1-3. WHEREIN: The said gas is supplied to the said process space from the said storage space, The said process space and the said storage space After closing the valve in between, an exhaust means for exhausting the gas in the storage space was provided. According to this configuration, when the valve between the processing space and the storage space is opened, the sample is etched in the processing space and a reaction product is generated. This reactant enters the storage space when the valve is open. For this reason, by setting it as the structure which discharges | emits the gas of storage space, it can prevent that a reaction product approachs into the upstream from the storage space, ie, can prevent upstream contamination.

  ADVANTAGE OF THE INVENTION According to this invention, the etching apparatus which can suppress the consumption of reactive gas can be provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, this etching apparatus is provided with an etching chamber 11 for processing a sample W such as a semiconductor wafer placed inside. The etching chamber 11 is connected to a buffer 13 having a fixed capacity via a pipe 12, and the buffer 13 is connected to a cylinder 15 as a gas supply source via a pipe 14. An etching gas for etching a predetermined portion of the sample W (for example, a sacrificial layer of MEMS) is supplied from the cylinder 15 into the etching chamber 11. In the present embodiment, xenon difluoride (XeF ₂ ) gas is used as the etching gas. Xenon difluoride is a solid at normal temperature and pressure. Gasified xenon difluoride is supplied from the cylinder 15 to the buffer 13 and from the buffer 13 to the etching chamber 11.

  The buffer 13 and the cylinder 15 are provided with heaters 13a and 15a, respectively. The heaters 13a and 15a are connected to the control device 16 so that the temperature can be individually controlled. The control device 16 is connected to a heater 11 a for adjusting the temperature of the etching chamber 11. Although not shown in the figure, the pipes 12 and 14 are also provided with a temperature adjusting member (heater) that is connected to the control device 16 and prevents condensation of xenon difluoride gas on the inner surface of the pipe. . The pipes 12 and 14 are provided with valves 12a and 14a, respectively. Each of the valves 12a and 14a is connected to the control device 16 so as to be individually controlled to open and close.

Next, the configuration of the etching chamber 11 will be described.
The etching chamber 11 is partitioned into a processing space 22 for etching the sample W and a storage space 23 for temporarily storing xenon difluoride gas supplied to the processing space 22 by the movement of the stage 21. The stage 21 prevents the xenon difluoride gas from flowing between the processing space 22 and the storage space 23. Accordingly, a plurality (two) of buffers are connected in series between the processing space 22 and the cylinder 15 by the buffer 13 and the storage space 23. The capacity of the storage space 23 is smaller than the capacity of the buffer 13.

  Specifically, as shown in FIG. 2, the etching chamber 11 includes a first chamber 24 and a second chamber 25 formed in a bottomed cylindrical shape. The first chamber 24 has a first opening 26 opened upward (upper side in FIG. 2), and the second chamber 25 has a second opening 27 opened downward (lower side in FIG. 2). The second opening 27 is formed with a smaller diameter than the first opening 26. The second chamber 25 is fixed to the first chamber 24 so that the first opening 26 and the second opening 27 face each other. The outer diameter of the second chamber 25 is formed larger than the inner diameter of the first chamber 24 (the diameter of the first opening 26). The first opening 26 is closed by the second chamber 25, and the airtightness in the etching chamber 11 is increased. Is to be maintained.

  The side wall 28 of the first chamber 24 is formed with a transport port 28a for carrying the sample W in and out, and the transport port 28a is provided with a gate 29 capable of closing the transport port 28a. The gate 29 is provided with a seal member (for example, an O-ring) 30 so that the etching chamber 11 is kept airtight when the gate 29 is closed. A pipe 12 is connected to the first chamber 24, and xenon difluoride is supplied from the cylinder 15 (buffer 13) into the storage space 23.

  Below the upper bottom 31 of the second chamber 25, a shower plate (diffusion plate) 32 that is formed in a disk shape and has many through holes is disposed to face the stage 21. The shower plate 32 is provided in a plurality of stages (two stages in the present embodiment) in the vertical direction, and the respective through holes formed in each shower plate 32 are arranged so as not to be coaxially positioned.

  The stage 21 is fixed on the base 33 and a disk-shaped base 33 that is smaller than the inner diameter of the first chamber 24 and larger than the inner diameter of the second chamber 25 (the diameter of the second opening 27). The mounting table 34 has a smaller diameter than the inner diameter of the chamber 25. A seal member 35 having a diameter larger than the inner diameter of the second chamber 25 is provided on the upper surface side of the outer peripheral edge of the base 33. A support base 37 is connected to the lower end of the base 33 via a columnar support member 36, and an actuator 38 that can move the support base 37 in the vertical direction is connected to the support base 37. . Accordingly, the stage 21 is provided so as to be movable in the vertical direction within the first chamber 24 by the actuator 38. The actuator 38 is connected to the control device 16 and its operation is controlled (see FIG. 1). In addition, a seal member 39 is provided between the first chamber 24 and each support member 36 to keep the inside of the etching chamber 11 airtight. Further, the sample W is mounted on the mounting table 34, and a fixing member 34a for preventing the displacement of the sample W along the outer periphery thereof is provided on the upper surface thereof.

  Then, as shown in FIG. 3, the stage 21 moves upward, and the outer peripheral edge of the base 33 abuts on the lower end 25 a as the opening end of the second chamber 25, so that the inside of the etching chamber 11 is connected to the processing space 22. It is partitioned into a storage space 23. The storage space 23 is defined by the first chamber 24 and the stage 21, and the processing space 22 is defined by the second chamber 25 and the stage 21.

  As shown in FIG. 1, the etching chamber 11 is connected to a dry pump (DP) 43 via pipes 41 and 42. Specifically, the dry pump 43 and the inside of the first chamber 24 are connected by a pipe 41 so that the gas in the storage space 23 can be discharged. Further, the dry pump 43 and the second chamber 25 are connected by a pipe 42 so that the gas in the processing space 22 can be discharged. Therefore, the control device 16, the pipe 41 and the dry pump 43 constitute an exhaust means. The dry pump 43 is connected to the control device 16 and its operation is controlled. The pipes 41 and 42 are provided with valves 41a and 42a, respectively, and the valves 41a and 42a are connected to the control device 16 so as to be openable and closable. Further, the dry pump 43 is connected to the buffer 13 via a pipe 44. The piping 44 is provided with a valve 44a, and the valve 44a is connected to the control device 16 so as to be able to be controlled individually.

  In the present embodiment, a pipe 45 is connected to the first chamber 24 and the second chamber 25, and the storage space 23 and the processing space 22 are communicated with each other, and the storage space 23 and the processing space 22 are connected via the pipe 45. The gas can move between the two. The pipe 45 is provided with a valve 45a, and the valve 45a is connected to the control device 16 so as to be capable of opening and closing. As shown in FIG. 3, the pipe 45 is connected between the side wall 28 of the first chamber 24 and the upper bottom 31 of the second chamber 25. The xenon difluoride gas supplied through the pipe 45 is uniformly diffused on the sample W by the shower plate 32.

  In this etching apparatus, the pressure in the storage space 23 is set higher than the pressure in the processing space 22, and the pressure in the cylinder 15 that is a gas supply source is set higher than the pressure in the storage space 23. Yes. Further, this etching apparatus is set so that the pressure in the buffer 13 is not less than the pressure in the storage space 23 and not more than the pressure in the cylinder 15. That is, the etching apparatus of the present embodiment supplies xenon difluoride gas from the cylinder 15 to the etching chamber 11 only by opening and closing the valve, and the pressure in the etching chamber 11 is solid of xenon difluoride at a predetermined temperature. It is configured to have a vapor pressure.

Next, the operation of the etching apparatus will be described.
(A) The control device 16 first carries the sample W into the etching chamber 11. Specifically, as shown in FIG. 2, the stage 29 is not in contact with the lower end of the first chamber 24, and the gate 29 is moved in a state where the etching chamber 11 is not partitioned into the processing space 22 and the storage space 23. The sample W is opened and is transferred into the etching chamber 11 by the transfer device 51 indicated by a one-dot chain line. The arm 52 that supports the sample W is formed in a fork shape. Then, a lift pin (not shown) provided in the stage 21 rises to receive the sample W supported by the arm 52, and after the transfer device 51 has left the etching chamber 11, the lift pin is lowered to cause the sample W to move to the stage 21. It is supposed to be placed on top. Subsequently, the control device 16 closes the gate 29 and raises the stage 21 to partition the inside of the etching chamber 11 into a processing space 22 and a storage space 23.

  (B1) When the sample W is loaded onto the stage 21, the control device 16 drives the dry pump 43 to discharge the gas in the processing space 22, the storage space 23, and the buffer 13, and the processing space 22, the storage space. 23 and the inside of the buffer 13 are set to a high vacuum. At this time, the valve 14a must be closed, but the valves 12a and 45a may be either closed or open. Thereafter, the control device 16 closes the valve in the open circuit state.

  (B2) The control device 16 opens the valve 14a, supplies xenon difluoride gas from the cylinder 15 to the buffer 13, and then closes the valve 14a. Next, the control device 16 opens the valve 12a to supply xenon difluoride gas from the buffer 13 to the storage space 23, and then closes the valve 12a.

  (C1) The control device 16 opens the valve 45a. Then, the xenon difluoride gas in the storage space 23 is supplied into the processing space 22 through the pipe 45. At this time, the gas in the storage space 23 is filled into the storage space 23 and the processing space 22. When the storage space 23 and the processing space 22 have the same pressure, the control device 16 closes the valve 45a. Specifically, the control device 16 obtains a time during which the storage space 23 and the processing space 22 have the same pressure in advance through experiments or the like, and closes the valve 45a after the time has elapsed.

  (C2) The xenon difluoride gas confined in the etching chamber 11 by the closing of the valve 45a etches the object (for example, molybdenum) of the sample W. The time for this etching is calculated in advance or experimentally based on the amount (pressure) of the xenon difluoride gas supplied to the processing space 22 and the reaction rate of the xenon difluoride gas. ing.

  (C3) The control device 16 opens the valve 42a, drives the dry pump 43 to suck out the gas in the processing space 22, and makes the pressure in the processing space 22 high vacuum. Thereby, the control device 16 discharges the gas used for the etching and the reaction product from the processing space 22.

  (C4) The control device 16 opens the valve 41a, drives the dry pump 43 to suck out the gas in the storage space 23, and sets the pressure in the storage space 23 to a high vacuum (for example, 20 mTorr (millitorr)). The valve 41a is closed.

  By sucking out the gas in the storage space 23, the reaction product generated in the processing space 22 is prevented from moving upstream in the gas supply path. That is, when the valve 45a is opened and the supply of the xenon difluoride gas to the processing space 22 is started, the sample W is etched by the supplied xenon difluoride gas. By this etching, fluoride (reaction product) is generated in the storage space 23. A part of this reaction product moves from the processing space 22 into the storage space 23 via the pipe 45. In this state, when the valve 12a is opened to supply the next xenon difluoride gas from the buffer 13 to the storage space 23, the reaction product moves from the storage space 23 to the buffer 13, and the xenon difluoride gas Reduce purity. For this reason, the reaction product can be discharged in a short time by discharging the gas in the storage space 23 having a smaller capacity than the buffer 13. At this time, the gas discharged from the storage space 23 is xenon difluoride mixed with the reaction product, but by setting the capacity of the storage space 23 small, the amount of xenon difluoride gas discharged is The amount of xenon difluoride gas discharged unnecessarily by the flow treatment can be reduced, that is, the consumption of expensive xenon difluoride gas can be reduced.

  (C5) The control device 16 opens the valve 12a and supplies the xenon difluoride gas in the buffer 13 to the storage space 23 via the pipe 12. At this time, since the capacity of the buffer 13 is set larger than the capacity of the storage space 23, the gas supply from the buffer 13 to the storage space 23 is completed in a short time. By performing this process after the gas in the storage space 23 is discharged, the xenon difluoride gas having a predetermined pressure can be supplied into the storage space 23.

  (C6) The control device 16 supplies xenon difluoride gas from the cylinder 15 to the buffer 13. At this time, the gas supply from the cylinder 15 to the buffer 13 may be supplied from the cylinder 15 to the buffer 13 by the amount of decrease in the buffer 13, that is, the amount of gas supplied from the buffer 13 to the storage space 23. The cylinder 15 is heated to a temperature (40 ° C.) at which the vapor pressure of xenon difluoride becomes a predetermined pressure. Therefore, the xenon difluoride in the cylinder 15 is sublimated, and the valve 14a between the cylinder 15 and the buffer 13 is opened to make the inside of the buffer 13 the same pressure as in the cylinder 15. The control device 16 closes the valve 14a when the buffer 13 and the cylinder 15 have the same pressure. Specifically, the control device 16 obtains a time during which the buffer 13 and the cylinder 15 are at the same pressure in advance through experiments or the like, and closes the valve 14a after the time has elapsed.

Next, the flow of the above processing for one gas supply to the etching chamber 11 will be described with reference to FIG.
In the period from time t0 to time t1, the process (C1) is performed. That is, the control device 16 opens the valve 45a at time t0 and closes the valve 45a at time t1.

  In the period from time t1 to time t6, the process (C2) is performed. During this period, the control device 16 performs a process that can be executed in a place other than the processing space 22 in parallel with the etching process. That is, in the period from time t1 to time t2, the control device 16 performs the process (C4). That is, the control device 16 opens the valve 41a and drives the dry pump 43 at time t1, closes the valve 41a and stops the dry pump 43 at time t2.

  Next, in the period from time t2 to time t6, the control device 16 performs the process (C6). That is, the control device 16 opens the valve 14a at time t2, and closes the valve 14a at time t6.

  Next, in the period from time t6 to time t7, the process (C3) is performed. At the same time, the process (C5) is performed. That is, at time t6, the control device 16 opens the valves 42a and 12a and drives the dry pump 43. At time t7, the control device 16 closes the valves 42a and 12a and stops the dry pump 43.

  The period from the time t0 to the time t7 is a process of supplying the gas to the processing space 22 once. The process from the time t0 to the time t7 is repeatedly performed a plurality of times, thereby etching the sample W. I do. Throughout the etching process. The etching chamber 11 is partitioned into a processing space 22 and a storage space 23. When the etching process is completed and the sample W is carried out, the dry pump 43 is driven to bring the processing space 22 and the storage space 23 to the same pressure (high vacuum), and then the stage 21 is lowered to perform the etching. After the chamber 11 is opened to the atmosphere, the sample W is unloaded by the transfer device 51.

  In FIG. 2, during the period from time t <b> 6 to time t <b> 2, the valve 14 a is closed and xenon difluoride is sublimated in the cylinder 15. That is, the sublimation of xenon difluoride is performed in parallel with the processes (C1), (C2), (C3), (C4), and (C5).

As described above, according to the present embodiment, the following effects can be obtained.
(1) The etching apparatus supplies xenon difluoride gas obtained by vaporizing solid xenon difluoride in the cylinder 15 to the etching chamber 11 and etches the sample W carried into the etching chamber 11. The etching apparatus is movably supported in the etching chamber 11, and is divided into a processing space 22 for etching the sample W and a storage space 23 for temporarily storing xenon difluoride gas supplied to the processing space 22. At the same time, a stage 21 that disables the flow of xenon difluoride gas between the processing space 22 and the storage space 23 is provided. Furthermore, a pipe 45 provided with a valve 45 a that communicates the processing space 22 and the storage space 23, and a control device 16 that controls opening and closing of the valve 45 a and supplies gas to the processing space 22. Therefore, when the stage 21 moves up and down, the inside of the etching chamber 11 is partitioned into a processing space 22 and a storage space 23. Therefore, the capacity of the processing space 22 for etching the sample W can be reduced as much as possible while ensuring a space in which the transfer device 51 can enter the etching chamber 11. Thereby, the quantity of the xenon difluoride discharged | emitted without reacting can be decreased, and the consumption of reactive gas can be suppressed. Further, since the storage space 23 can function as a buffer, the number of parts of the etching apparatus can be reduced as compared with a case where a separate buffer is provided.

  (2) A buffer that is connected to the etching chamber 11 and the cylinder 15 via pipes 12 and 14 having valves 12a and 14a that are controlled to open and close by the control device 16 and that has a capacity larger than the capacity of the storage space 23. 13 was provided. Therefore, a plurality (two) of buffers are connected in series between the processing space 22 and the cylinder 15 by the buffer 13 and the storage space 23. And since the capacity | capacitance of the buffer 13 is set larger than the capacity | capacitance of the process space 22, after supplying gas to the storage space 23 from the buffer 13, when supplying gas with respect to the buffer 13 from the cylinder 15, storage space is shown. Since it is sufficient to supply the gas to the buffer 13 by the amount supplied to 23, the supply time of the xenon difluoride gas obtained by vaporizing the raw material having a low vapor pressure can be shortened.

  (3) The etching chamber 11 has a first opening 26 that opens upward, a bottomed circular first chamber 24 in which the stage 21 can be moved up and down, and a smaller diameter than the first opening 26. The second opening 27 is provided, and the first opening 26 and the second opening 27 are opposed to each other, the first opening 26 is closed, and the bottomed circular second chamber 25 provided in the first chamber 24 is provided. . A storage space 23 is defined by the first chamber 24 and the stage 21 with the stage 21 closing the second opening 27 in a disc shape, and the processing space 22 is formed by the second chamber 25 and the stage 21. Was made to be compartmentalized. Therefore, the first opening 26 is closed when the stage contacts the lower end 25 a of the first chamber 24, and the etching chamber 11 is partitioned into the processing space 22 and the storage space 23. It is not necessary to make the stage and the first and second chambers complicated, such as forming a recess in which is placed, and the etching apparatus can be configured simply.

  (4) A xenon difluoride gas is supplied from the storage space 23 to the processing space 22 and the valve 45a between the processing space 22 and the storage space 23 is closed, and then a dry pump 43 that exhausts the gas in the storage space 23 is provided. It was. For this reason, when the valve 45a between the processing space 22 and the storage space 23 is opened, the sample is etched in the processing space 22 to generate a reactant. This reactant enters the storage space 23 by opening the valve 45a. For this reason, by setting it as the structure which discharges the gas of the storage space 23, it can prevent that a reaction product approachs into the upstream from the storage space 23, ie, can prevent upstream contamination.

  (5) Since the piping 45 communicates the processing space 22 and the storage space 23 partitioned in the etching chamber 11, the entire length of the piping 45 is larger than that in the case of connecting the etching chamber configured separately and the buffer. The xenon difluoride gas can be quickly supplied from the storage space 23 to the processing space 22.

  (6) The stage 21 is composed of a base 33 and a mounting table 34 having a smaller diameter than the second opening. Therefore, the capacity of the processing space 22 can be easily changed by changing the size of the mounting table 34.

(7) Since the xenon difluoride gas is used as the etching gas, high selectivity can be obtained in the etching of the silicon or molybdenum of the sample W.
(8) The pressure in the storage space 23 is set higher than the pressure in the processing space 22, and the pressure in the cylinder 15 is set higher than the pressure in the storage space 23. Furthermore, this etching apparatus was set so that the pressure in the buffer 13 was not less than the pressure in the storage space 23 and not more than the pressure in the cylinder 15. Therefore, the etching apparatus can supply the xenon difluoride gas from the cylinder 15 to the processing space 22 only by opening and closing the valves 12a, 14a, and 45a. As a result, the time required for maintenance is reduced, that is, it is possible to suppress a reduction in operating rate.

In addition, you may implement the said one Embodiment in the following aspects.
In the above embodiment, the process of (C4) is performed for each process of supplying the gas to the process space 22 once. However, the process is not limited to this, and the storage space 23 is necessary for the etching process on the sample W. An amount of xenon difluoride gas may be supplied at a time, and the xenon difluoride gas in the storage space may not be discharged until the etching process on the sample W is completed. In this case, after exhausting the gas in the processing space 22, the valve 45 a is opened and supplied from the storage space 23 to the processing space 22. That is, in the period from time t0 to time t7 in FIG. 4, the processes (C4) and (C5) are not performed. In this way, the consumption of xenon difluoride gas can be further suppressed.

  In the above embodiment, the processing space 22 and the storage space 23 are partitioned by the stage 21 coming into contact with the lower end 25a of the second chamber 25. However, the present invention is not limited to this. For example, the first chamber 24 and the second chamber 25 are arranged with the up and down positions reversed, and the stage is configured to hold the sample W from above, and the stage is lowered to the lower side of the first chamber. The processing space 22 and the storage space 23 may be partitioned by coming into contact with the upper end of the second chamber disposed in the chamber.

  In the above embodiment, the etching chamber 11 includes the first chamber 24 having the first opening 26 opened upward, and the second chamber 25 having the second opening 27 having a smaller diameter than the first opening 26, and the stage 21 was comprised in disk shape. However, the present invention is not limited to this, and the first opening 26 and the second opening 27 are formed to have the same diameter, and the stage is formed in a box shape having an upper opening, and the stage abuts on the upper bottom of the second chamber. The inside of the stage on which the sample W is placed may be used as a processing space.

In the above embodiment, the first and second chambers 24 and 25 are formed in a bottomed cylindrical shape, but the present invention is not limited to this, and may be formed in a bottomed cylindrical shape such as a bottomed rectangular tube shape.
In the above embodiment, the outer diameter of the second chamber 25 is formed larger than the inner diameter of the first chamber 24, but the present invention is not limited to this. For example, the outer diameter of the second chamber is formed smaller than the inner diameter of the first chamber, an annular member having an opening smaller than the outer diameter of the second chamber is provided in the first opening of the first chamber, The second chamber may be fixed.

In the above embodiment, the stage 21 is configured by the base 33 and the mounting table 34, but the present invention is not limited thereto, and the stage may be configured by only the base 33.
In the above embodiment, the sample W is carried into the etching chamber 11 under atmospheric pressure. However, the present invention is not limited to this, and a preliminary chamber connected to the transfer port 28a of the etching chamber 11 is provided. May be maintained at a high vacuum. In such a configuration, the sample W is once carried into the preliminary chamber, and the preliminary chamber is brought to a high vacuum, and then the sample W is carried into the etching chamber 11. The sample W is carried out in reverse.

  In the above embodiment, the capacity of the storage space is configured to be variable, and the capacity of the storage space is reduced while the xenon difluoride gas is supplied so that the xenon difluoride gas is supplied to the processing space. It may be.

In the above embodiment, xenon difluoride is used as the etching gas. However, the present invention is not limited to this, and other gases such as bromine trifluoride (BrF ₃ ) may be used as the etching gas.
In the embodiment described above, an inert gas such as nitrogen or argon may be mixed and supplied to the etching chamber 11 (processing space 22) in addition to the xenon difluoride gas.

The schematic block diagram of an etching apparatus. Sectional drawing of the etching chamber of the state which is not divided into processing space and storage space. Sectional drawing of the etching chamber of the state divided into processing space and storage space. Explanatory drawing which shows the procedure of an etching process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Etching chamber, 12, 14, 41, 42, 44, 45 ... Piping, 12a, 14a, 41a, 42a, 44a, 45a ... Valve, 13 ... Buffer, 16 ... Control device, 21 ... Stage, 22 ... Processing space , 23 ... Reservation space, 24 ... First chamber, 25 ... Second chamber, 25a ... Lower end, 26 ... First opening, 27 ... Second opening, 43 ... Dry pump, W ... Sample.

Claims (4)

An etching apparatus for supplying a gas obtained by vaporizing a raw material in a gas supply source to an etching chamber and etching a sample carried into the etching chamber,
The etching chamber is movably supported and divides the etching chamber into a processing space for etching the sample and a storage space for temporarily storing the gas supplied to the processing space, and the processing space; A stage that disables the flow of the gas to and from the storage space;
A pipe communicating the processing space and the storage space;
An etching apparatus comprising: a control device that controls opening and closing of a valve provided in the pipe to supply the gas to the processing space.   A buffer that is connected to the etching chamber and the gas supply source through a pipe having a valve that is controlled to open and close by the control device, and has a capacity set larger than the capacity of the storage space, is provided. The etching apparatus according to claim 1. The etching chamber is
A first chamber having a first opening that opens upward, wherein the stage is provided so as to be movable in the vertical direction inside;
A second chamber having a second opening smaller than the first opening, the second chamber being provided so as to face the first opening and the second opening;
The stage is formed in a plate shape capable of closing the second opening,
2. The processing space is defined by the second chamber and the stage in a state where the stage is in contact with an opening end of the second chamber and the second opening is closed. 2. The etching apparatus according to 2.   The apparatus according to claim 1, further comprising an exhaust unit configured to exhaust the gas in the storage space after supplying the gas from the storage space to the processing space and closing a valve between the processing space and the storage space. The etching apparatus as described in any one of 1-3.

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