Etching equipment

Abstract

To provide an etching apparatus that can more reliably remove objects made of high-melting-point metals. [Solution] The etching apparatus (1) comprises a processing container (11), a gas supply unit (12) for supplying XeF2 gas into the processing container (11), a processing object placement table (13) on which a processing object (S) containing a high-melting-point metal to be removed is placed, a processing object heater (14) for heating the processing object (S) placed on the processing object placement table (13), a temperature control unit (141) for controlling the processing object heater (14) so ​​that the temperature of the processing object (S) is higher than the boiling point of a complete fluoride formed by the complete fluoride of the high-melting-point metal and the boiling point of a predetermined intermediate having fewer fluorine atoms than the complete fluoride, and an exhaust mechanism (15) for discharging gas from inside the processing container (11).

Description

Technical Field

[0001] The present invention relates to an etching apparatus for removing an object to be removed composed of a refractory metal, which is a metal having a melting point of 1600°C or higher and adhering to a processing object, from the processing object.

Background Art

[0002] When manufacturing devices such as MEMS, metal masks and sacrificial layers are used. Examples of materials used for these metal masks and sacrificial layers include refractory metals such as Mo (molybdenum), W (tungsten), Ti (titanium), Cr (chromium), and Pt (platinum). Metal masks and sacrificial layers composed of these refractory metals need to be finally removed from the processing object. Hereinafter, these metal masks, sacrificial layers, etc. that are objects to be removed are referred to as "objects to be removed".

[0003] Conventionally, when removing an object to be removed composed of a refractory metal, a method of vaporizing it by reacting with a gas composed of a fluoride has been used. Patent Document 1 describes an etching method and apparatus in which a processing object having an object to be removed composed of Mo or W is heated to a temperature within the range of 50 to 120°C, and the object to be removed is brought into contact with an etching gas composed of XeF2 (xenon difluoride). When Mo or W reacts with XeF2, MoF6 (molybdenum hexafluoride) or WF6 (tungsten hexafluoride) is generated. Since these have low boiling points (MoF6 is 35°C and WF6 is 17°C), the object to be removed composed of Mo or W becomes a gas and is removed from the processing object. Further, since XeF2 becomes Xe, which is a noble gas, by this reaction and is discharged together with MoF6 or WF6, there is no adverse effect such as the residue of the etching gas adhering to the processing object.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] Since both Mo and W are transition metals, their fluorides can exist not only as completely fluorinated perfect fluorides (with 6 F atoms), such as MoF6 and WF6, but also as stable intermediates with fewer F atoms, such as MoF5 and WF5. Because these intermediates have higher boiling points than the perfect fluorides (MoF5 at 215°C, WF5 at 216°C), the method and apparatus described in Patent Document 1 leave these intermediates in the treated material, making it impossible to reliably remove the target material.

[0006] Although this explanation uses Mo and W as described in Patent Document 1 as examples, similar problems arise when removing materials made of other high-melting-point metals such as Ti, Cr, and Pt.

[0007] The problem that this invention aims to solve is to provide an etching apparatus that can more reliably remove objects made of high-melting-point metals. [Means for solving the problem]

[0008] The etching apparatus according to the present invention, which was developed to solve the above problems, a) Processing container and b) A gas supply unit that supplies XeF2 gas into the processing container, c) A processing object placement platform on which the object to be processed, which is contained in the processing container and has a substance to be removed made of a high melting point metal attached to it, d) A heater for heating the object to be processed, which is placed on the object to be processed platform, e) A temperature control unit that controls the heater of the object to be processed so that the temperature of the object to be processed is higher than the boiling point of a complete fluoride formed by the complete fluoride of the high-melting-point metal and the boiling point of a predetermined intermediate having fewer fluorine atoms than the complete fluoride, f) An exhaust mechanism for discharging gas from the processing container and It is equipped with.

[0009] The boiling points of the perfect fluorides and intermediates of high-melting-point metals are as follows, for example, when the high-melting-point metal is Mo, W, Ti, Cr, and Pt (Mo and W are listed again). Mo: The boiling point of the complete fluoride (MoF6) is 35°C, and the boiling point of the intermediate (MoF5) is 215°C. W: Boiling point of complete fluoride (WF6) is 17°C, and boiling point of intermediate (WF5) is 216°C. Ti: The boiling point (sublimation temperature) of the complete fluoride (TiF4) is 284°C, and the boiling point of the intermediate (TiF3) is 1400°C. Cr: The boiling point of the complete fluoride (CrF5) is 117°C, and the boiling point of the intermediate (CrF4) is 400°C. Pt: The boiling point of the complete fluoride (PtF6) is 69°C, and the boiling point of the intermediate (PtF5) is 300-305°C. Although the maximum oxidation state that Cr can take is +6 (hexavalent chromium), CrF6 (chromium hexafluoride) does not exist (it has not been successfully synthesized), therefore, the complete fluoride of Cr in this invention is CrF5 (chromium pentafluoride).

[0010] The etching apparatus according to the present invention places a workpiece to be processed, to which a material to be removed made of a high-melting-point metal is attached, on a workpiece placement platform in a processing container. The workpiece heater is then heated to a temperature higher than the boiling point of the complete fluoride of the high-melting-point metal and the boiling point of a predetermined intermediate of the high-melting-point metal by controlling the workpiece heater with a temperature control unit, while XeF2 gas is supplied into the processing container from a gas supply unit. As a result, the workpiece to be removed made of a high-melting-point metal reacts with the XeF2 gas, generating the complete fluoride and intermediate of the high-melting-point metal. Since both the generated complete fluoride and intermediate are gases at the above temperature, they are discharged outside the processing container by an exhaust mechanism. This makes it possible to remove the material to be removed from the workpiece without leaving behind not only the complete fluoride of the high-melting-point metal but also the intermediate.

[0011] The etching apparatus according to the present invention is Furthermore, the processing container is equipped with a gas outflow prevention weir consisting of a cylindrical body that surrounds the object to be processed which is placed on the object to be processed platform, The gas supply unit supplies the XeF2 gas into the gas leakage prevention weir. It is preferable.

[0012] By equipping the system with such a gas leakage prevention weir, it is possible to prevent the spatial distribution of XeF2 gas from becoming non-uniform, thereby preventing the material to be removed from being etched non-uniformly.

[0013] The etching apparatus equipped with the aforementioned gas outflow prevention weir further, A processing object loading / unloading mechanism for loading and unloading the processing object onto the processing object platform, A gas leakage prevention weir movement mechanism moves the aforementioned gas leakage prevention weir between an installation position which surrounds the object to be treated and a retraction position above that position. It is preferable to include the following.

[0014] With a configuration that includes a processing object loading / unloading mechanism and a gas leakage prevention weir relocation mechanism, when loading or unloading processing objects onto a processing object platform using the processing object loading / unloading mechanism, the gas leakage prevention weir can be moved from its installation position to a retracted position, allowing processing objects to be loaded and unloaded without being obstructed by the gas leakage prevention weir. Furthermore, after loading the processing objects, the gas leakage prevention weir can be moved back to its installation position using the processing object loading / unloading mechanism before etching, thereby preventing uneven etching of the materials to be removed.

[0015] In the etching apparatus according to the present invention, as the temperature (heating temperature) at which the object to be processed heater heats the object to be processed increases, the temperature difference in the processing vessel increases, and the convection of XeF2 gas becomes stronger. This convection becomes remarkable when the heating temperature exceeds 400°C, and the heat supplied from the object to be processed heater to the object to be processed easily escapes outside the object to be processed through the gas. Therefore, it is preferable that the temperature control unit controls the object to be processed heater so that the heating temperature is (a temperature higher than the boiling point of the complete fluoride and the boiling point of the predetermined intermediate as described above, and) 400°C or lower. In order to further suppress the influence of convection, the heating temperature is preferably (a temperature higher than the above-mentioned boiling point, and) 350°C or lower, and more preferably 310°C or lower.

[0016] Also, when the pressure in the processing vessel is high, the convection of XeF2 gas tends to occur easily. Therefore, the pressure in the processing vessel after supplying XeF2 gas is preferably 120 Pa or lower.

Effect of the Invention

[0017] According to the etching apparatus of the present invention, by etching an object to be processed to which a removal object made of a high melting point metal adheres with XeF2 gas while heating it to a temperature higher than the boiling point of the complete fluoride of the high melting point metal and the boiling point of the intermediate, the removal object can be removed more reliably.

Brief Description of the Drawings

[0018] [Figure 1] A longitudinal sectional view showing an embodiment of the etching apparatus according to the present invention. [Figure 2] In the etching apparatus of this embodiment, it is a partial longitudinal sectional view showing an enlarged view of an object to be processed mounting table or the like, and shows a state (a) in which the push-up pin is lowered and a state (b) in which it is raised. [Figure 3] A longitudinal sectional view showing a state when an object to be processed is carried in and out of the object to be processed mounting table 13 in the etching apparatus of this embodiment. [Figure 4]A partial longitudinal cross-sectional view showing the operation of the push-up pins and gas leakage prevention weir when the object to be processed is removed from the object placement platform. [Modes for carrying out the invention]

[0019] An embodiment of the etching apparatus according to the present invention will be explained using Figures 1 to 4.

[0020] (1) Configuration of the etching apparatus of this embodiment The etching apparatus 1 of this embodiment includes a processing container 11, a gas supply unit 12, a processing object placement platform 13, a processing object heater 14, an exhaust mechanism 15, a gas leakage prevention weir 16, a gas leakage prevention weir movement mechanism 17, and a processing object loading / unloading mechanism 18.

[0021] The gas supply unit 12 includes a XeF2 gas source 120, a gas channel 121 through which the XeF2 gas generated by the XeF2 gas source 120 flows, which is provided inside the top plate 112 of the processing container 11, and a diffusion plate 122 provided on the wall of the processing container 11 on the side of the internal space 111 within the gas channel 121. The XeF2 gas source 120 includes a containment chamber 1201 containing solid XeF2, and a heater (provided separately from the processing object heater 14) 1202 that heats the inside of the containment chamber 1201 to a temperature higher than the boiling point of XeF2 (75.6°C). Furthermore, the XeF2 gas source 120 is connected to the gas flow path 121 via a buffer tank 1203, and a first gas supply valve 1204 is provided between the XeF2 gas source 120 and the buffer tank 1203, and a second gas supply valve 1205 is provided between the buffer tank 1203 and the gas flow path 121. The XeF2 gas generated in the XeF2 gas source 120 is supplied from the diffuser plate 122 to the internal space 111 of the processing container 11 through the buffer tank 1203 and the gas flow path 121.

[0022] The processing object placement platform 13 is positioned in the internal space 111 of the processing container 11, facing the diffusion plate 122. The bottom plate 113 of the processing container 11 has an opening 114, and the processing object placement platform 13 is fixed to the bottom plate 113 so as to close this opening 114. An O-ring is provided between the processing object placement platform 13 and the bottom plate 113 to prevent gas from the internal space 111 from leaking out through the opening 114. The processing object S is placed on the upper surface of the processing object placement platform 13.

[0023] The processing object placement platform 13 includes a vertically penetrating push-up pin insertion hole 131, a push-up pin 132, a push-up pin guide tube 133 fixed to the lower end of the push-up pin insertion hole 131, an intermediate plate 134 fixed to the lower end of the push-up pin guide tube 133 and having a vertically penetrating hole 1341, a lifting member 135 fixed to the lower end of the push-up pin 132, an air cylinder 136 for raising and lowering the lifting member 135, and an airtight sealing bellows member 137 that airtightly surrounds the push-up pin 132 between the intermediate plate 134 and the lifting member 135 (see Figure 2(a)). The push-up pin 132 is inserted into the push-up pin insertion hole 131 from below through the hole 1341 in the intermediate plate 134 and the push-up pin guide tube 133. When removing the object to be processed S, which is placed on the object to be processed platform 13, after etching, the push-up pin 132 is pushed up via the lifting member 135 using the air cylinder 136, thereby raising the tip of the push-up pin 132 above the upper surface of the object to be processed platform 13, and thereby lifting the object to be processed S (Figure 2(b)). Note that in all figures except Figure 2, the push-up pin guide tube 133, intermediate plate 134, lifting member 135, air cylinder 136, and airtight bellows member 137 are not shown.

[0024] In this embodiment, the planar shape of the object to be processed platform 13 is circular. Instead of a circle, an object to be processed platform 13 with a planar shape such as a square or rectangle, or a polygon other than a square, such as a hexagon, may also be used.

[0025] In this embodiment, Inconel, a nickel alloy, was used as the material for the processing object placement platform 13. Instead of Inconel, aluminum (Al) or aluminum composite material (see Patent Document 2), which is a composite material in which aluminum is impregnated into an alumina (Al2O3) support, can also be used. The surface of the processing object placement platform 13 may be coated with a material resistant to XeF2 gas, such as quartz, to prevent reaction with XeF2 gas.

[0026] The object heater 14 is a heater embedded in the object placement platform 13. In this embodiment, a tungsten heater was used. Instead of a tungsten heater, an aluminum nitride (AlN) ceramic heater or the like may be used for the object heater 14. A temperature control unit 141 and a power supply 142 are provided outside the processing container 11. The power supply 142 is connected to the object heater 14 by wiring that passes through the opening 114. The temperature control unit 141 and the power supply 142 are connected by a control signal line that transmits a control signal from the temperature control unit 141 to the power supply 142. Furthermore, a temperature sensor 143 is embedded near the upper surface inside the object placement platform 13. The temperature sensor 143 is connected to the temperature control unit 141 by a detection signal line that transmits a detection signal from the temperature sensor 143 and passes through the opening 114.

[0027] The temperature control unit 141 controls the magnitude of the current supplied from the power supply 142 to the workpiece heater 14 so that the temperature of the workpiece S (more precisely, the vicinity of the workpiece S) determined from the detection signal transmitted from the temperature sensor 143 reaches a predetermined set temperature (described later along with the operation of the etching apparatus 1). This is implemented by combining hardware and software. Here, the set temperature is set to a temperature higher than the boiling point of the complete fluoride, which is formed when the high-melting-point metal constituting the material to be removed attached to the workpiece S is completely fluorinated, and also higher than the boiling point of the intermediate, which has fewer fluorine atoms than the complete fluoride.

[0028] The set temperature can be set, for example, by providing an input unit such as a keyboard in the temperature control unit 141 and having the operator input the numerical value of the set temperature using the input unit. Alternatively, the temperature control unit 141 may be further equipped with a storage unit that stores the set temperatures for each element of high-melting-point metals, and when the operator specifies an element using the input unit, the temperature control unit 141 may read the set temperature corresponding to that element from the storage unit.

[0029] The exhaust mechanism 15 includes a vacuum pump 151, an exhaust pipe 152 connecting the processing container 11 and the vacuum pump 151, and an exhaust valve 153 provided in the exhaust pipe 152. Downstream of the vacuum pump 151, a gas recovery mechanism (not shown) is provided to remove and recover gas molecules of XeF2, elemental Xe, and fluorides of high-melting-point metals from the exhausted gas. The XeF2 recovered here consists of gas molecules supplied from the gas supply unit 12 that did not react with the high-melting-point metals attached to the object to be processed S, elemental Xe is obtained when XeF2 reacts with the high-melting-point metals and loses its F atoms, and fluorides of high-melting-point metals are obtained when high-melting-point metals attached to the object to be processed S react with XeF2 and are removed from the object to be processed S.

[0030] The gas leakage prevention weir 16 is a cylindrical member provided in the internal space 111 of the processing container 11, above the processing object placement platform 13. Although the gas leakage prevention weir 16 is not an essential component of the present invention, if the gas leakage prevention weir 16 is not provided, the supplied XeF2 gas will continue to flow outward along the surface of the processing object S until the internal space 111 is pressurized. As a result, the etching rate at the outer periphery of the processing object S will be faster than at the center, and the uniformity of the processing will tend to be poor. In contrast, by using the gas leakage prevention weir 16, the flow of such XeF2 gas can be reduced early, and the uniformity of the processing can be improved. For this reason, it is preferable to use the gas leakage prevention weir 16.

[0031] In this embodiment, the gas leakage prevention weir 16 is cylindrical in shape to match the planar shape of the processing object placement platform 13, and its inner diameter is 204 mm. This inner diameter was determined assuming that the processing object S is a circular wafer with an outer diameter of 200 mm. However, the size of the gas leakage prevention weir 16 is not limited to this example. Furthermore, if the processing object placement platform 13 or the processing object S placed on it is not circular (polygonal), the gas leakage prevention weir 16 may also be a polygonal cylinder or a circular one.

[0032] Quartz is used as the material for the gas leakage prevention weir 16 because it has excellent heat resistance when heated by the heating element heater 14. On the other hand, if the quartz gas leakage prevention weir 16 collides with the heating element platform 13 when descending, chipping may occur at the lower end. Therefore, a protective device 161 made of metal (e.g., stainless steel, nickel alloy (Inconel), etc.) is provided at the lower end of the gas leakage prevention weir 16, which has an annular member with approximately the same outer and inner diameter as the gas leakage prevention weir 16. The gas leakage prevention weir 16 and the protective device 161 are joined by Kovar welding.

[0033] The gas leakage prevention weir 16 is further provided with claw portions 162 extending laterally from its upper end. The claw portions 162 may be provided around the entire circumference (360°) of the gas leakage prevention weir 16, or only around a portion of the circumference. If the claw portions 162 are provided only around a portion of the circumference, they may be provided in only one location or in multiple locations. The claw portions 162 are used when the gas leakage prevention weir 16 is moved up and down by the gas leakage prevention weir moving mechanism 17, as will be described below.

[0034] The gas leakage prevention weir relocation mechanism 17 is a device that moves the gas leakage prevention weir 16 between an installation position (the position where the gas leakage prevention weir 16 is depicted in Figure 1) where it is positioned to surround the object to be processed S placed on the object to be processed platform 13, and a retraction position above the installation position (the position where the gas leakage prevention weir 16 is depicted in Figure 3). At the installation position, the gas leakage prevention weir 16 is positioned so that its lower end is in contact with the upper surface of the object to be processed platform 13. With the gas leakage prevention weir 16 positioned in this manner, the XeF2 gas released from the diffusion plate 122 of the gas supply unit 12 is supplied into the cylinder of the gas leakage prevention weir 16.

[0035] The gas spill prevention weir movement mechanism 17 includes a claw support section 171 that supports at least a portion of the claw portion 162 of the gas spill prevention weir 16 from below, a lifting rod 172 made of a rod material connected to the upper part of the claw support section 171 that penetrates a hole provided in the top plate 112 and whose upper end reaches the outside of the processing container 11, a lifting rod housing section 173 that airtightly houses the lifting rod 172 outside the processing container 11, and a lifting mechanism 174 that moves (lifts and lowers) the lifting rod 172 up and down. If one or more claw portions 162 are provided only in a part of the perimeter of the gas spill prevention weir 16, the same number of claw support sections 171 as the number of claw portions 162 may be provided. Also, if claw portions 162 are provided over the entire gas spill prevention weir 16, only one claw support section 171 may be provided, or multiple claw support sections 171 may be provided. The lifting rod housing section 173 is equipped with an O-ring between it and the upper surface of the top plate 112 to prevent air from entering the internal space 111 of the processing container 11 through the gap between the lifting rod 172 and the hole provided in the top plate 112. Part of the lifting rod housing section 173 is a bellows-like section 1731, and airtightness is maintained as the bellows-like section 1731 expands and contracts even when the lifting rod 172 moves up and down.

[0036] The processing object loading / unloading mechanism 18 includes a load lock chamber 181 located to the side of the processing container 11, a gate 182 located between the processing container 11 and the load lock chamber 181, a robot hand 183 located inside the load lock chamber 181, and an exhaust mechanism (not shown) for exhausting the load lock chamber 181. In Figures 1 and 3, only a portion of the load lock chamber 181 near the processing container 11 is shown. The robot hand 183 can enter the internal space 111 of the processing container 11 when the gate 182 is open.

[0037] (2) Operation of the etching apparatus of this embodiment The operation of etching apparatus 1 will be explained with reference to Figures 1 to 4.

[0038] (2-1) Bringing in the materials to be processed First, with the gate 182 closed, the object to be processed S is placed inside the load lock chamber 181, and then the load lock chamber 181 is evacuated by the exhaust mechanism of the object loading / unloading mechanism 18. In parallel, the internal space 111 of the processing container 11 is also evacuated by the exhaust mechanism 15. In addition, the gas outflow prevention weir moving mechanism 17 raises the claw support part 171 via the lifting rod 172 using the lifting mechanism 174, thereby raising the claw part 162 of the gas outflow prevention weir 16, and thereby moving the entire gas outflow prevention weir 16 upwards. After both exhausts are complete, the gate 182 is opened. Then, the object to be processed S is loaded from inside the load lock chamber 181 into the internal space 111 of the processing container 11 by the robot hand 183 and placed on the upper surface of the object to be processed platform 13 (Figure 3). During this loading process, the gas leakage prevention weir 16 is moved upward, so it does not get in the way. After the loading of the object to be processed S is complete, the robot hand 183 is moved out of the internal space 111 and the gate 182 is closed (Figure 1). During this time, the exhaust of the load lock chamber 181 and the internal space 111 of the processing container 11 is continued, maintaining a pressure below a predetermined level.

[0039] (2-2) Etching Next, the gas leakage prevention weir moving mechanism 17 lowers the claw support portion 171, thereby lowering the claw portion 162 of the gas leakage prevention weir 16, moving the entire gas leakage prevention weir 16 downwards until the lower end of the protective device 161 touches the upper surface of the processing object placement platform 13. As a result, the area around the processing object S is surrounded by the gas leakage prevention weir 16.

[0040] Next, the gas supply unit 12 supplies XeF2 gas to the internal space 111 of the processing container 11, including the inside of the gas leakage prevention weir 16, thereby bringing the object to be processed S into contact with the XeF2 gas. The first gas supply valve 1204 and the second gas supply valve 1205 are closed in advance. At the XeF2 gas source 120, solid XeF2 is heated by the heater 1202 to generate XeF2 gas in the containment chamber 1201. In this state, if the first gas supply valve 1204 is opened while the second gas supply valve 1205 remains closed, the XeF2 gas generated at the XeF2 gas source 120 flows into the buffer tank 1203. When the buffer tank 1203 is pressurized to the vapor pressure of XeF2 gas at the current temperature (usually about 400 Pa), the inflow of XeF2 gas stops. After that, the first gas supply valve 1204 is closed. After the above operations are completed, or in parallel with these operations, the vacuum pump 151 is operated to open the exhaust valve 153, thereby reducing the pressure in the internal space 111 and the gas flow path 121 of the processing container 11 (to, for example, 10 Pa). Next, the exhaust valve 153 is closed and the second gas supply valve 1205 is opened. As a result, the XeF2 gas in the buffer tank 1203 is supplied from the diffuser plate 122 to the internal space 111 of the processing container 11 through the gas flow path 121. In this embodiment, the pressure in the internal space 111 is in the range of 100 to 120 Pa. By keeping the pressure below 120 Pa, convection of the XeF2 gas in the internal space 111 is suppressed, thereby preventing the heat supplied from the processing object heater 14 to the processing object S from escaping outside the processing object S, and increasing the heating efficiency.

[0041] Furthermore, the temperature control unit 141 controls the power supply 142 to supply current to the object heater 14. As a result, the object heater 14 is heated, and the temperature of the object S rises. The temperature control unit 141 then obtains the current temperature of the object S from the detection signal transmitted from the temperature sensor 143 and controls the magnitude of the current so that the temperature reaches a predetermined set temperature.

[0042] Here, the set temperature is set to a temperature higher than the boiling point of the complete fluoride formed by the complete fluoride of the high-melting-point metal assumed to be attached to the object S being treated, and also higher than the boiling point of the intermediate, which has fewer fluorine atoms than the complete fluoride. For many high-melting-point metals, the intermediate has a higher boiling point than the complete fluoride, so the set temperature should be higher than the boiling point of the intermediate. For example, if the high-melting-point metal assumed to be attached is Mo, the temperature should be set higher than the boiling point of its intermediate, MoF5, which is 215°C. Similarly, if the high-melting-point metal is W, Ti, Cr, and Pt, the temperatures should be 216°C (boiling point of WF5) or higher, 1400°C (boiling point of TiF3) or higher, 400°C (boiling point of CrF4) or higher, and 300-305°C (boiling point of PtF5) or higher, respectively.

[0043] Furthermore, it is preferable to set the temperature to 400°C or lower. This suppresses the convection of XeF2 gas within the processing container and prevents a decrease in the efficiency of heating the object S to be processed. Moreover, it is more preferable that the set temperature be 350°C or lower, and even more preferable that it be 310°C or lower.

[0044] By heating the object to be treated S to a predetermined temperature higher than the boiling points of the complete fluoride and intermediates while bringing it into contact with XeF2 gas, the high-melting-point metals adhering to the object to be treated S are removed from the object to be treated S as complete fluoride and / or intermediate gases. At this time, it is possible to prevent intermediates with a boiling point higher than that of the complete fluoride from remaining on the surface of the object to be treated S. In addition, because the object to be treated S is surrounded by a gas outflow prevention weir 16, it is possible to prevent the spatial distribution of XeF2 gas on the surface of the object to be treated S from becoming uneven, thereby preventing the removal material from being etched unevenly.

[0045] After etching is performed for a predetermined time, the exhaust valve 153 is opened to exhaust the XeF2 gas used in the etching process, as well as the complete fluoride and / or intermediate gases formed from vaporized high-melting-point metals, until the pressure in the internal space 111 reaches approximately 10 Pa. This completes the etching process. Here, by controlling the workpiece heater 14 to a constant temperature even after the etching is complete, it is possible to prevent the temperature of the workpiece S from dropping below the boiling point of the intermediate during the supply of XeF2 gas, thus preventing the intermediate from remaining attached to the surface of the workpiece S. Note that the order of supplying XeF2 gas and current does not matter when starting etching; both may be performed simultaneously.

[0046] (2-3) Removal of materials to be processed After etching is complete, the gas leakage prevention weir movement mechanism 17 raises the gas leakage prevention weir 16 to a position where it does not obstruct the removal of the object to be processed S (Figure 4). Next, the push-up pin 132 is raised, and the tip of the push-up pin 132 pushes up the lower surface of the object to be processed S (Figures 2(b) and 4). Then, the gate 182 is opened, and the robot hand 183 enters the internal space 111 of the processing container 11. The robot hand 183 is inserted into the gap created between the lower surface of the object to be processed S and the upper surface of the object to be processed platform 13 by the push-up pin 132, and the robot hand 183 captures the object to be processed S and pulls it into the load lock chamber 181. As a result, the object to be processed S is removed.

[0047] The embodiments of the etching apparatus according to the present invention have been described above. However, it is needless to say that the present invention is not limited to the above embodiments and various modifications are possible. For example, the gas outflow prevention weir 16 and the gas outflow prevention weir moving mechanism 17 are not essential in the present invention and may be omitted. Alternatively, the gas outflow prevention weir 16 may be provided and fixed to the upper surface of the object to be processed mounting table 13. When the gas outflow prevention weir 16 is fixed in this way, the top plate 112 of the processing container 11 can be made openable and closable, and the object to be processed S can be carried in and out from above the processing container 11 onto the object to be processed mounting table 13 inside the gas outflow prevention weir.

Explanation of Reference Numerals

[0048] 1...Etching apparatus 11...Processing container 111...Internal space of the processing container 112...Top plate of the processing container 113...Bottom plate of the processing container 114...Opening provided in the bottom plate of the processing container 12...Gas supply unit 120...XeF2 gas generation source 1201...Containment chamber 1202...Heater of the XeF2 gas generation source 1203...Buffer tank 1204...First gas supply valve 1205...Second gas supply valve 121...Gas flow path 122...Diffusion plate 13...Object to be processed mounting table 131...Pushing pin insertion hole 132...Pushing pin 133...Pushing pin guide tube 134...Intermediate plate 1341...Hole in the intermediate plate 135...Lifting member 136...Air cylinder 137...Bellows member for airtight holding 14...Object to be processed heater 141...Temperature control unit 142...Power supply 143...Temperature sensor 15…Exhaust mechanism 151…Vacuum pump 152... Exhaust pipe 153... Exhaust valve 16…Gas leak prevention weir 161… Protective equipment 162... Nail area 17...Gas leak prevention weir relocation mechanism 171...Claw support part 172...Lifting rod 173... Elevator storage area 174... Lifting mechanism 18... Processing object loading / unloading mechanism 181... Load Lock Room 182...Gate 183... Robot Hand

Claims

1. a) Processing container and b) XeF 2 The gas supply unit that supplies gas, c) A processing object placement platform on which the object to be processed, which is contained in the processing container and has a substance to be removed made of a high melting point metal attached to it, d) A heater for heating the object to be processed, which is placed on the object to be processed platform, e) A temperature control unit that controls the heater of the object to be processed so that the temperature of the object to be processed is higher than the boiling point of a complete fluoride formed by the complete fluoride of the high-melting-point metal and the boiling point of a predetermined intermediate having fewer fluorine atoms than the complete fluoride, f) An exhaust mechanism for discharging gas from the processing container and An etching apparatus equipped with the following features.

2. Furthermore, the processing container is equipped with a gas outflow prevention weir consisting of a cylindrical body that surrounds the object to be processed which is placed on the object to be processed platform, The gas supply unit contains the XeF within the gas outflow prevention weir. 2 It supplies gas. The etching apparatus according to claim 1.

3. moreover, A processing object loading / unloading mechanism for loading and unloading the processing object onto the processing object platform, A gas leakage prevention weir movement mechanism moves the aforementioned gas leakage prevention weir between an installation position which surrounds the object to be treated and a retraction position above that position. The etching apparatus according to claim 2, comprising:

4. The etching apparatus according to any one of claims 1 to 3, wherein the temperature control unit controls the heater of the object to be processed so that the temperature is 400°C or less.

5. The etching apparatus according to any one of claims 1 to 3, wherein the temperature control unit controls the heater of the workpiece to be processed to a temperature higher than the boiling point of the complete fluoride and intermediate of a high-melting-point metal selected from Mo, W, Ti, Cr, and Pt.

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