JP7233266B2 - Stage equipment and processing equipment - Google Patents

Description

The present disclosure relates to stage devices and processing devices.

2. Description of the Related Art There are processes that require extremely low temperatures as processing apparatuses for substrates such as semiconductor substrates, such as film forming apparatuses. For example, in order to obtain a magnetoresistive element having a high magnetoresistive ratio, a technique of forming a magnetic film in an ultra-high vacuum and extremely low temperature environment is known.

As a technique for processing a substrate at an extremely low temperature, Patent Document 1 discloses that after the substrate is cooled to an extremely low temperature in a cooling processing apparatus, a magnetic film is formed on the cooled substrate at an extremely low temperature by a separately provided film forming apparatus. It is described that a film is formed.

Further, in Patent Document 2, a cooling head cooled by a refrigerator is provided in a vacuum chamber, a cooling stage as a support for supporting a substrate is fixed to the cooling head, and the substrate is cooled to an extremely low temperature on the cooling stage. A technique for performing a thin film forming process while performing a thin film forming process is described.

JP 2015-226010 A Japanese Patent Application Laid-Open No. 2006-73608

The present disclosure provides a stage device and a processing device that can rotate a mounted substrate in a state of being cooled to an extremely low temperature and that has high cooling performance.

A stage device according to an aspect of the present disclosure includes a stage that holds a substrate to be processed in a vacuum vessel, and a stage that is fixed to the back side of the stage with a gap therebetween, and is cooled to an extremely low temperature by a refrigerator. a refrigeration heat transfer body, a cooling fluid supplied to the gap for transferring cold heat of the refrigeration heat transfer body to the stage, a rotatable support for the stage, and an upper portion of the refrigeration heat transfer body a stage supporting portion having a cylindrical shape and having a vacuum insulation structure; and a rotating portion that supports the stage supporting portion and is rotationally driven by a driving mechanism in a state sealed with a magnetic fluid, wherein the stage A body portion of the support portion has a double-tube structure consisting of an inner tube and an outer tube, an internal space between the inner tube and the outer tube is held in a vacuum, and the stage support portion It is arranged in a vacuum space communicating with a container, the outer tube has a plurality of through holes, and the inner space communicates with the vacuum space through the through holes to form a vacuum space.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a stage device and a processing device that can rotate a mounted substrate in a state of being cooled to an extremely low temperature and that has high cooling performance.

1 is a schematic cross-sectional view showing an example of a processing apparatus provided with a stage device according to one embodiment; FIG. FIG. 10 is a schematic diagram showing another example of the shape of comb teeth in the stage device according to one embodiment; FIG. 10 is a diagram showing an example in which a contact mechanism is provided to bring the first heat transfer section and the second heat transfer section into contact with each other by raising and lowering the refrigerating heat transfer body, and the first heat transfer section and the second heat transfer section are separated from each other; Indicates status. FIG. 10 is a diagram showing an example in which a contact/separation mechanism is provided to move the refrigerating heat transfer body up and down to contact and separate the first heat transfer section and the second heat transfer section, and the first heat transfer section and the second heat transfer section are in contact with each other; indicates the state of FIG. 11 is a diagram showing an example in which a ring-shaped bimetal member is provided between the first heat transfer section and the second heat transfer section to provide a contact/separation mechanism for contacting and separating the first heat transfer section and the second heat transfer section; There is, and the state where the 1st heat transfer part and the 2nd heat transfer part spaced apart is shown. FIG. 11 is a diagram showing an example in which a ring-shaped bimetal member is provided between the first heat transfer section and the second heat transfer section to provide a contact/separation mechanism for contacting and separating the first heat transfer section and the second heat transfer section; There is a state in which the first heat transfer section and the second heat transfer section are in contact with each other. FIG. 4 is a cross-sectional view showing a first example of a heat insulation structure of a stage support; 6 is a partial cross-sectional view showing a modification in which a radiant heat shield is provided on the surface of the outer tube of the stage support portion of FIG. 5; FIG. FIG. 10 is a cross-sectional view showing a second example of the heat insulation structure of the stage support; FIG. 11 is a cross-sectional view showing a third example of the heat insulation structure of the stage support; FIG. 9 is a partial cross-sectional view showing a modification in which a radiation heat shield is provided on the surface of the inner tube of the stage support portion of FIG. 8; FIG. 12 is a cross-sectional view showing a fourth example of the heat insulation structure of the stage support;

Embodiments will be specifically described below with reference to the accompanying drawings.
<Processing device>
First, an example of a processing apparatus having a stage device according to one embodiment will be described. FIG. 1 is a schematic cross-sectional view showing an example of such a processing apparatus.

As shown in FIG. 1, the processing apparatus 1 includes a vacuum vessel 10, a target 30, and a stage device 50. As shown in FIG. The processing apparatus 1 can sputter-deposit a magnetic film on a semiconductor wafer (hereinafter simply referred to as "wafer") W, which is a substrate to be processed, in an ultra-high vacuum and extremely low temperature environment in a processing vessel 10. It is configured as a possible film forming apparatus. A magnetic film is used, for example, in a tunneling magnetoresistance (TMR) element.

The vacuum vessel 10 is a processing vessel for processing wafers W, which are substrates to be processed. An exhaust means (not shown) such as a vacuum pump capable of reducing pressure to an ultra-high vacuum is connected to the vacuum vessel 10, and the interior thereof is configured to be able to reduce pressure to an ultra-high vacuum (for example, 10 ⁻⁵ Pa or less). ing. A gas supply pipe (not shown) is connected to the vacuum vessel 10 from the outside, and a sputtering gas necessary for sputtering film formation (eg, argon (Ar) gas, krypton (Kr) gas, neon ( A rare gas such as Ne) gas or nitrogen gas) is supplied. A loading/unloading port (not shown) for the wafer W is formed in the side wall of the vacuum chamber 10, and the loading/unloading port can be opened and closed by a gate valve (not shown).

The target 30 is provided in the upper part of the vacuum vessel 10 so as to face above the wafer W held by the stage device 50 . An AC voltage is applied to the target 30 from a power supply for plasma generation (not shown). When an AC voltage is applied to the target 30 from the plasma generating power source while the sputtering gas is introduced into the vacuum vessel 10, plasma of the sputtering gas is generated within the vacuum vessel 10, and the ions in the plasma cause the target 30 to be shrunk. is sputtered. Atoms or molecules of the sputtered target material are deposited on the surface of the wafer W held by the stage device 50 . Although the number of targets 30 is not particularly limited, a plurality of targets is preferable from the viewpoint that films of different materials can be formed with one processing apparatus 1 . For example, when depositing a magnetic film (a film containing a ferromagnetic material such as Ni, Fe, Co, etc.), the material of the target 30 can be CoFe, FeNi, NiFeCo, for example. Further, as the material of the target 30, these materials containing another element can also be used.

As will be described later, the stage device 50 holds the wafer W on a stage 56 and cools the wafer W to an extremely low temperature while rotating it.

The processing apparatus 1 also has an elevating mechanism 74 that elevates the entire stage device 50 with respect to the vacuum vessel 10 . Thereby, the distance between the target 30 and the wafer W can be controlled. Specifically, the stage device 50 is moved up and down by the lifting mechanism 74 to change the position of the stage 56 to the transport position when the wafer W is placed on the stage 56 and the wafer W placed on the stage 56 . It can be moved to and from the processing position when performing the membrane.

<Stage device>
Next, the stage device 50 according to one embodiment will be described in detail.
As shown in FIG. 1 , the stage device 50 has a refrigerator 52 , a refrigerating heat conductor 54 , a stage 56 , a stage support section 58 , a seal rotation mechanism 62 and a drive mechanism 68 .

The refrigerator 52 holds the frozen heat transfer body 54 and cools the upper surface of the frozen heat transfer body 54 to an extremely low temperature (for example, −30° C. or lower). The refrigerator 52 has a cold head portion 52 a in its upper portion, and cold heat is transferred from the cold head portion 52 a to the refrigerating heat transfer body 54 . The refrigerator 52 is preferably of a type using a GM (Gifford-McMahon) cycle from the viewpoint of cooling capacity. When forming the magnetic film used for the TMR element, the cooling temperature of the refrigerating heat transfer member 54 by the refrigerator 52 is preferably in the range of -23 to -223°C (250 to 50K). The heating mode can be set by driving the refrigerating cycle of the refrigerator 52 in a reverse cycle. By setting the refrigerator 52 to the heating mode during maintenance or the like, it is possible to heat the stage 56 via the refrigerating heat transfer member 54 and return it to normal temperature.

The refrigerating heat conductor 54 is fixedly arranged on the refrigerator 52 and has a substantially cylindrical shape, and is made of a material having high thermal conductivity such as pure copper (Cu). The upper portion of the refrigerating heat transfer body 54 is arranged inside the vacuum vessel 10 .

The refrigerating heat transfer element 54 is arranged below the stage 56 so that its center coincides with the central axis C of the stage 56 . A first cooling gas supply passage 54a through which a first cooling gas can flow is formed along the central axis C inside the refrigerating heat transfer body 54, and the first cooling gas is supplied from a gas supply source (not shown). A first cooling gas is supplied to the supply path 54a. Helium (He) gas having high thermal conductivity is preferably used as the first cooling gas.

The stage 56 is arranged with a gap G (for example, 2 mm or less) between it and the upper surface of the refrigerating heat transfer element 54 . The stage 56 is made of a material with high thermal conductivity such as pure copper (Cu). The gap G communicates with a first cooling gas supply passage 54 a formed inside the refrigerating heat transfer body 54 . Therefore, the cryogenic first cooling gas cooled by the refrigeration heat transfer body 54 is supplied to the gap G from the first cooling gas supply passage 54a. As a result, the cold heat of the refrigerator 52 is transferred to the stage 56 via the first cooling gas supplied to the refrigerating heat transfer element 54 and the gap G, and the stage 56 reaches an extremely low temperature (for example, −30° C. or lower). Cooled.

By forming the first cooling gas supply passage 54a from the lower end to the upper end of the refrigerating heat transfer element 54 in this manner, the first cooling gas supplied from the outside of the apparatus can be sufficiently cooled. As a result, the heat transfer in the gap G is not hindered by the temperature of the first cooling gas itself, so the stage 56 can be efficiently cooled to an extremely low temperature.

A mesh member may be inserted into the first cooling gas supply path 54a for the purpose of increasing the cooling efficiency of the first cooling gas flowing through the first cooling gas supply path 54a by the refrigerating heat transfer body 54 . As a result, the contact area between the first cooling gas flowing through the first cooling gas supply path 54a and the refrigerating heat transfer member 54 is increased, and the first cooling gas can be efficiently cooled.

As a means for cooling the stage, in addition to using the cooling gas as described above, a liquid refrigerant such as antifreeze may be used, and the gap G may be filled with thermally conductive grease having good thermal conductivity. Furthermore, a compressor, an expansion valve, a pressure regulating valve, and the like may be connected to the first cooling gas supply path 54a to form a refrigerator circulation system, thereby performing cooling using a high-pressure, low-boiling-point gas. When the gap G is filled with thermally conductive grease, there is no need to provide the first cooling gas supply path 54a, so there is an advantage that the structure of the refrigerating heat transfer element 54 can be simplified.

Further, a pressure adjustment mechanism may be provided to adjust the pressure of the first cooling gas flowing through the first cooling gas supply path 54a. Since the heat transfer coefficient of the first cooling gas can be adjusted by adjusting the pressure, various sputtering processes in different temperature ranges can be handled.

Stage 56 includes an electrostatic chuck 56a. The electrostatic chuck 56a is made of a dielectric film and has a chuck electrode 56b embedded therein. A predetermined DC voltage is applied through the wiring L to the chuck electrode 56b. Thereby, the wafer W can be attracted and fixed by the electrostatic attraction force.

The stage 56 has a first heat transfer portion 56c below the electrostatic chuck 56a, and a convex portion 56d protruding toward the refrigerating heat transfer body 54 is formed on the lower surface of the first heat transfer portion 56c. ing. In the illustrated example, the convex portion 56 d is composed of two annular portions surrounding the central axis C of the stage 56 . The height of the convex portion 56d can be, for example, 40 to 50 mm. The width of the convex portion 56d can be, for example, 6 to 7 mm. The shape and number of the projections 56d are not particularly limited, but from the viewpoint of increasing the heat transfer efficiency with the refrigerating heat transfer body 54, the shape and number are set so that the surface area is sufficient for heat exchange. is preferred.

The refrigeration heat transfer element 54 has a second heat transfer part 54b on the upper surface of the main body, that is, on the surface facing the first heat transfer part 56c. A concave portion 54c is formed in the second heat transfer portion 54b so as to be fitted with a gap G with respect to the convex portion 56d. In the illustrated example, the recessed portion 54 c is composed of two annular portions surrounding the central axis C of the stage 56 . The height of the concave portion 54c may be the same as the height of the convex portion 56d, and may be, for example, 40-50 mm. The width of the concave portion 54c can be, for example, slightly wider than the width of the convex portion 56c, and is preferably 7 to 9 mm, for example. The shape and number of the concave portions 54c are determined so as to correspond to the shape and number of the convex portions 56c.

The convex portion 56d of the first heat transfer portion 56c and the concave portion 54c of the second heat transfer portion 54b are fitted with a gap G therebetween to form a comb tooth portion. By providing the comb tooth portion in this way, the gap G is bent, so that the heat generated by the first cooling gas between the first heat transfer portion 56c of the stage 56 and the second heat transfer portion 54b of the refrigerating heat transfer body 55 is reduced. Transmission efficiency can be increased.

As shown in FIG. 2, the convex portion 56d and the concave portion 54c may have corrugated shapes. Further, it is preferable that the surfaces of the convex portion 56d and the concave portion 54c are roughened by blasting or the like. As a result, the surface area for heat transfer can be increased to further improve the heat transfer efficiency.

Note that the first heat transfer portion 56c may be provided with a recess, and the second heat transfer portion 54b may be provided with a protrusion corresponding to the recess.

The electrostatic chuck 56a and the first heat transfer portion 56c of the stage 56 may be integrally molded or separately molded and joined together. Further, the main body of the refrigerating heat transfer body 54 and the second heat transfer part 54b may be integrally formed, or may be formed separately and joined together.

The stage 56 is formed with a through hole 56e penetrating vertically. A second cooling gas supply path 57 is connected to the through hole 56e, and the second cooling gas for heat transfer is supplied to the rear surface of the wafer W from the second cooling gas supply path 57 through the through hole 56e. . Like the first cooling gas, He gas having high thermal conductivity is preferably used as the second cooling gas. By supplying the second cooling gas to the back surface of the wafer W, that is, between the wafer W and the electrostatic chuck 56a, the cold heat of the stage 56 is efficiently transferred to the wafer W via the second cooling gas. be able to. Although one through-hole 56e may be provided, a plurality of through-holes 56e is preferable from the viewpoint of transferring the cold heat of the refrigerating heat transfer body 54 to the wafer W particularly efficiently.

By separating the flow path of the second cooling gas supplied to the back surface of the wafer W from the flow path of the first cooling gas supplied to the gap G, a desired cooling gas can be obtained on the back surface of the wafer W regardless of the supply of the first cooling gas. Cooling gas can be supplied with pressure and flow rate. At the same time, it is possible to continuously supply a high-pressure, cryogenic cooling gas to the gap G between the wafers W without being restricted by the pressure, flow rate, supply timing, and the like of the gas supplied to the rear surface.

A part of the first cooling gas may be supplied to the rear surface of the wafer W as the cooling gas by providing a through hole connected to the gap G in the stage 56 .

A contact/separation mechanism for contacting/separating the first heat transfer portion 56c and the second heat transfer portion 54b may be provided to enable contact/separation between the first heat transfer portion 56c and the second heat transfer portion 54b. By providing the contact/separation mechanism, when the stage 56 is not rotating, the first heat transfer section 56c and the second heat transfer section 54b are brought into contact with each other to enhance heat transfer therebetween, resulting in rapid cooling or cooling. It can handle heating. For example, in the case of cooling only with a cooling gas, temperature drift may occur when the wafer W is placed on the stage 56, but the first heat transfer portion 56c and the second heat transfer portion 54b are brought into contact with each other for rapid cooling. By doing so, the temperature drift can be suppressed. Further, by bringing the first heat transfer portion 56c and the second heat transfer portion 54b into contact with each other, it is possible to drive the refrigerating cycle of the refrigerator 52 in a reverse cycle and return the stage 56 to room temperature in a short time. .

As the contact/separation mechanism, as shown in FIGS. 3A and 3B, a mechanism for raising and lowering the refrigerating heat transfer body 54 (including the second heat transfer portion 54b) can be used. FIG. 3A shows a state in which the first heat transfer section 56c and the second heat transfer section 54b are separated from each other with the gap G therebetween, and FIG. A state in which the heat transfer portion 54b is brought into contact with the heat transfer portion 54b is shown. At this time, the second heat insulating structure 71, which will be described later, preferably has a bellows 71a so as to be able to follow the elevation of the refrigerating heat transfer body 54, as shown in the drawing. Moreover, as shown in the figure, it is preferable to provide a gas flow path 56f in the first heat transfer portion 56c. As a result, even when the first heat transfer portion 56c and the second heat transfer portion 54b are in contact with each other, the stage 56 can be cooled by the first cooling gas. When the refrigerating heat transfer member 54 is lifted and lowered, it is preferable to move it up and down together with the refrigerator 52 . Alternatively, only the refrigerating heat transfer body 54 may be raised and lowered while being fixed. As the contact/separation mechanism, instead of raising and lowering the refrigerating heat transfer body 54, the stage 56 (including the first heat transfer section 56c) may be raised and lowered.

Further, the first heat transfer portion 56c and the second heat transfer portion 54b are connected as a contact/separation mechanism while maintaining the state in which the gap G is formed between the first heat transfer portion 56c and the second heat transfer portion 54b. A metal member for contacting and separating may be arranged. Specifically, such a metal member is arranged between the first heat transfer portion 56c and the second heat transfer portion 54b and is deformed by applying a voltage to bring them into contact or apart. can be mentioned. For example, as shown in FIGS. 4A and 4B, a ring-shaped bimetal member 91 is provided between the first heat transfer portion 56c and the second heat transfer portion 54b. In this example, a ring-shaped bimetal member 91 is installed on the second heat transfer portion 54b, and a ring-shaped movable portion (bimetal) 91a is provided on the first heat transfer portion 56c side. A voltage can be applied to the bimetal member 91 by wiring a wire from an external power supply via, for example, the first cooling gas supply path 54a. FIG. 4A shows a state in which no voltage is applied, and the movable portion (bimetal) 91a is separated from the first heat transfer portion 56c. In FIG. 4B, the voltage application causes the movable portion (bimetal) 91a to deform and come into contact with the first heat transfer portion 56c. In the case of this example as well, even if the first heat transfer portion 56c is provided with the gas flow path 56f and the first heat transfer portion 56c and the second heat transfer portion 54b are in contact with each other, the stage 56 is cooled by the first cooling gas. It is preferable to allow cooling. A bimetallic member 91 may be installed on the first heat transfer portion 56c to bring the movable portion (bimetal) 91a into contact with and separate from the second heat transfer portion 54b. Further, the contact/separation mechanism using such a metal member may be of a fin type that deforms in the vertical direction when a voltage is applied.

The stage support portion 58 is arranged outside the refrigerating heat transfer body 54 and rotatably supports the stage 56 (see FIG. 1). In the illustrated example, the stage support portion 58 has a substantially cylindrical body portion 58a and a flange portion 58b extending outward from the lower surface of the body portion 58a. The main body portion 58 a is arranged to cover the gap G and the outer peripheral surface of the upper portion of the refrigerating heat transfer body 54 . As a result, the stage support portion 58 also has a function of shielding the gap G, which is the connection portion between the refrigerating heat transfer element 54 and the stage 56 . The stage support portion 58 has a heat insulating structure as will be described later. The main body portion 58a has a reduced diameter portion 58c at its axial center portion. The body portion 58a and the flange portion 58b are made of metal such as stainless steel.

A heat insulating member 60 is connected to the lower surface of the flange portion 58b. The heat insulating member 60 has an annular shape coaxial with the flange portion 58b and is fixed to the flange portion 58b. The heat insulating member 60 is made of ceramics such as alumina.

The seal rotating mechanism 62 is provided below the heat insulating member 60 . The seal rotating mechanism 62 has a rotating portion 62a, an inner fixing portion 62b, an outer fixing portion 62c, and a heating means 62d.

The rotating portion 62a has a substantially cylindrical shape that extends downward coaxially with the heat insulating member 60, and is airtightly sealed with magnetic fluid to the inner fixed portion 62b and the outer fixed portion 62c. is rotated by Since the rotating portion 62a is connected to the stage support portion 58 via the heat insulating member 60, the heat insulating member 60 blocks the transmission of cold heat from the stage support portion 58 to the rotating portion 62a. For this reason, it is possible to suppress deterioration in sealing performance and occurrence of dew condensation due to a decrease in the temperature of the magnetic fluid in the seal rotating mechanism 62 .

The inner fixed portion 62b has a substantially cylindrical shape with an inner diameter larger than the outer diameter of the refrigerating heat transfer body 54 and an outer diameter smaller than the inner diameter of the rotating portion 62a. is provided via a magnetic fluid.

The outer fixed portion 62c has a substantially cylindrical shape with an inner diameter larger than the outer diameter of the rotating portion 62a, and is provided outside the rotating portion 62a via a magnetic fluid.

The heating means 62 d is embedded inside the inner fixing portion 62 b and heats the entire seal rotation mechanism 62 . As a result, it is possible to prevent the temperature of the magnetic fluid from dropping, the sealing performance from deteriorating, and the occurrence of dew condensation.

With such a configuration, the seal rotation mechanism 62 can rotate the stage support section 58 while the area communicating with the vacuum vessel 10 is hermetically sealed with the magnetic fluid and held in vacuum.

A bellows 64 is provided between the upper surface of the outer fixing portion 62c and the lower surface of the vacuum vessel 10. As shown in FIG. The bellows 64 is a metallic bellows structure that can be expanded and contracted in the vertical direction. The bellows 64 surrounds the refrigerating heat transfer member 54, the stage support portion 58, and the heat insulating member 60, and separates the space within the vacuum vessel 10 and the vacuum-held space communicating therewith from the atmospheric space.

A slip ring 66 is provided below the seal rotation mechanism 62 . The slip ring 66 has a rotating body 66a including a metal ring and a fixed body 66b including brushes. The rotating body 66a is fixed to the lower surface of the rotating portion 62a of the seal rotating mechanism 62 and has a substantially cylindrical shape extending downward coaxially with the rotating portion 62a. The fixed body 66b has a substantially cylindrical shape with an inner diameter slightly larger than the outer diameter of the rotating body 66a.

The slip ring 66 is electrically connected to a DC power supply (not shown), and transmits the voltage supplied from the DC power supply to the wiring L via the brushes of the stationary body 66b and the metal ring of the rotating body 66a. do. As a result, a voltage can be applied from the DC power supply to the chuck electrode without twisting the wiring L or the like. A rotating body 66 a of the slip ring 66 is rotated via a drive mechanism 68 .

The drive mechanism 68 is a direct drive motor having a rotor 68a and a stator 68b. The rotor 68a has a substantially cylindrical shape extending coaxially with the rotating body 66a of the slip ring 66, and is fixed to the rotating body 66a. The stator 68b has a substantially cylindrical shape with an inner diameter larger than the outer diameter of the rotor 68a. When the driving mechanism 68 is driven, the rotor 68a rotates, and the rotation of the rotor 68a is transmitted to the stage 56 via the rotating body 66a, the rotating portion 62a, and the stage support portion 58. The wafer W rotates with respect to the frozen heat conductor 54 . In FIG. 1, the rotating members are shown with dots for convenience.

Although an example of a direct drive motor is shown as the drive mechanism 68, the drive mechanism 68 may be driven via a belt or the like.

The second tube has a cylindrical shape with a double-pipe structure so as to cover the cold head part 52a of the refrigerator 52 and the lower part of the refrigerating heat transfer element 54, and has a vacuum insulation structure (vacuum double-pipe structure) in which the inside is evacuated. 1 thermal insulation structure 70 is provided. Cooling performance due to heat input from the outside such as the driving mechanism 68 to the lower part of the cold head refrigerator 52 and the refrigerating heat transfer body 54 that are important for cooling the stage 56 and the wafer W by the first heat insulating structure 70 can be suppressed.

A second heat insulating structure having a cylindrical shape with a vacuum double tube structure whose inside is evacuated so as to overlap the inside of the first heat insulating structure 70 so as to cover almost the entire refrigerating heat transfer body 54 . A body 71 is provided. The second heat insulating structure 71 can suppress deterioration in cooling performance due to heat input from the outside such as the first cooling gas leaked into the magnetic fluid seal or the space S to the refrigerating heat transfer body 54 . By overlapping the first heat insulating structure 70 and the second heat insulating structure 71 under the refrigerating heat transfer body 54, the uninsulated portion of the refrigerating heat transfer body 54 can be eliminated, and the cold head portion 52a and the cold head portion 52a Thermal insulation in the vicinity can be enhanced.

In addition, the first heat insulating structure 70 and the second heat insulating structure 71 can suppress the transmission of the cold heat of the refrigerator 52 and the refrigerating heat transfer body 54 to the outside.

A seal member 81 is provided between the lower end portion of the diameter-reduced portion 58 c of the main body portion 58 a of the stage support portion 58 and the second heat insulating structure 71 . A space S sealed with a sealing member 81 is formed between the main body portion 58a of the stage support portion 58, the second heat transfer portion 54b of the refrigerating heat transfer member 54, and the upper portion of the second heat insulation structure 71. ing. The first cooling gas leaked from the gap G flows into the space S. A gas flow path 72 is connected to the space S through the sealing member 81 . The gas flow path 72 extends downward from the space S. A sealing member 82 seals between the upper surface of the second heat insulating structure 71 and the second heat transfer portion 54b of the refrigerating heat transfer body 54 . The seal member 82 prevents the first cooling gas leaking into the space S from being supplied to the body portion of the refrigerating heat transfer body 54 .

The gas flow path 72 may discharge the gas in the space S or may supply the space S with the cooling gas. Both when the gas passage 72 discharges the gas and when the cooling gas is supplied, the first cooling gas is prevented from entering the seal rotation mechanism 62 and the sealing performance is prevented from decreasing due to the temperature drop of the magnetic fluid. can do. That is, when the gas flow path 72 has a gas discharge function, the first cooling gas leaked into the space S can be discharged before reaching the seal rotating mechanism 62 . Further, when the gas flow path 72 has a cooling gas supply function, the third cooling gas is supplied so as to function as a counterflow to the first cooling gas leaking from the gap G. From the viewpoint of enhancing the counterflow function, the supply pressure of the third cooling gas is preferably substantially the same as or slightly higher than the supply pressure of the first cooling gas.

Further, when the gas flow path 72 has a gas discharge function, the discharge of the first cooling gas from the gap G is promoted, and fresh first cooling gas is supplied to the gap G from the first cooling gas supply path 54a. It also has the effect of being able to

Furthermore, when the gas flow path 72 has a gas supply function, the third cooling gas supplied to the space S may be argon (Ar) gas or neon (Ne) gas, which has higher thermal conductivity than the first cooling gas. Low gas can be used to prevent condensation.

The stage device 50 may have a temperature sensor for detecting temperatures of the refrigerating heat conductor 54, the gap G, and the like. As the temperature sensor, for example, a temperature sensor for low temperatures such as a silicon diode temperature sensor and a platinum resistance temperature sensor can be used.

<Heat insulation structure of stage support>
Next, the heat insulation structure of the stage support portion 58 of the stage device 50 will be described.
As described above, the stage support portion 58 rotatably supports the stage 56 and is in direct contact with the stage 56 cooled by the refrigerating heat transfer body 54 . Also, the stage support portion 58 is close to a seal rotation mechanism 62 having a magnetic fluid seal. When the temperature of the magnetic fluid drops, the magnetic fluid seal deteriorates in sealing performance and causes dew condensation. Further, when the stage 56 is rotated, shear heat is generated in the magnetic fluid. As a result, the temperature of the seal rotation mechanism 62 reaches a high temperature of about 100° C. (373 K), and this heat is transferred to the stage support portion 58 and enters the stage 56, deteriorating the cooling performance for cooling the stage 56. Moreover, the stage support portion 58 receives radiant heat from the outside, and this radiant heat also affects the cooling performance.

Therefore, the stage support portion 58 is made to have a heat insulating structure, and the heat transferred to the stage support portion 58 and supplied to the stage 56 is suppressed as much as possible. In general, a material with low thermal conductivity is selected in order to increase the heat insulation of a member. The desired thermal insulation effect cannot be obtained because the temperature is reached close to the temperature. Therefore, in the present embodiment, at least part of the stage support section 58 has a vacuum insulation structure.

As described above, the stage support portion 58 has the diameter-reduced portion 58c at the center portion in the axial direction of the main body portion 58a, and this structure also contributes to heat insulation. That is, the inside of the stage support portion 58 is a space S through which the first cooling gas leaks through the gap G. If this space S is wide, the amount of heat exchanged with the leaked first cooling gas increases. There is a possibility that the temperature of the cooling gas leaking from the gap G has increased, and the temperature of the stage support portion 58 may increase due to heat exchange. By providing the reduced-diameter portion 58c, the volume of the space S can be reduced, and the temperature rise of the stage support portion 58 due to such heat exchange can be suppressed.

Several examples of the vacuum insulation structure of the stage support section 58 will be described below.

[First example of heat insulation structure of stage support part]
FIG. 5 is a cross-sectional view showing a first example of the heat insulating structure of the stage support portion 58. As shown in FIG.
In this example, the body portion 58a of the stage support portion 58 has a double tube structure of an inner tube 581 and an outer tube 582, and an internal space 583 between the inner tube 581 and the outer tube 582 is evacuated. It is held to form a vacuum insulation structure with a vacuum double tube structure. Thereby, high heat insulation can be obtained. Horizontal portions 584 and 585 corresponding to the diameter-reduced portion 58b of the main body portion 58a of the stage support portion 58 are made of a solid plate with no space in order to ensure strength.

Since the inner tube 581 and the outer tube 582 form a double tube structure, the strength can be maintained even if they are thin. The thinner the inner tube 581 and the outer tube 582 are, the greater the heat resistance can be, and the heat insulating effect can be enhanced. The thickness of the inner tube 581 and the outer tube 582 is, for example, 0.3 mm.

A method for forming such a vacuum double tube structure is not particularly limited. For example, after the internal space 583 is evacuated, it can be sealed so that the internal space 583 between the inner tube 581 and the outer tube 582 is always a vacuum layer.

In the example of FIG. 5, the stage support member 58 is arranged inside the bellows 64, and since its arrangement position is a vacuum space communicating with the vacuum vessel 10, the vacuum state is utilized. That is, an outer tube 582 having a plurality of through holes 586 is used. As a result, the internal space 583 can be brought into a high vacuum via the through hole 586, and a vacuum insulation structure of a vacuum double tube structure can be obtained.

After evacuating the inside of the space as described above, it takes a long time to manufacture the sealing structure, and there is a possibility that the degree of vacuum may decrease in a long period of time. On the other hand, by utilizing the vacuum of the vacuum container 10, the internal space 583 can be easily evacuated, and there is no risk of vacuum deterioration.

Further, as shown in FIG. 6, a configuration in which a radiant heat shield 587 is further provided outside the outer tube 582 may be employed. The stage support portion 58 receives radiant heat from the outside in addition to heat transfer from the magnetic fluid seal portion 62, and this radiant heat also affects the cooling performance. By providing the radiant heat shield 587, the radiant heat from the outside to the stage support portion 58 can be shielded, and the cooling performance can be further improved. Aluminum can be suitably used as the radiation heat shield 587 . As the radiant heat shield 587, a base made of resin or the like on which aluminum is vapor-deposited, or a member to which aluminum foil is attached can be used. Further, the radiation heat shielding member 587 may be formed by directly vapor-depositing aluminum or the like on the outer tube 582 or directly attaching aluminum foil or the like.

[Second example of heat insulation structure of stage support part]
FIG. 7 is a cross-sectional view showing a second example of the heat insulating structure of the stage support portion 58. As shown in FIG.
In this example, as in the first example, the main body portion 58a of the stage support portion 58 has a double-tube structure consisting of an inner tube 581 and an outer tube 582. A space 583 is held in a vacuum to form a vacuum insulation structure of a vacuum double tube structure. However, in this example, the solid plate horizontal portions 584 and 586, which do not have a space, are not provided, and the entire body portion 58a of the stage support portion 58 has a vacuum double-tube structure.

If there is no problem with the strength, by forming the entire main body 58a into a vacuum double-tube structure in this way, heat exchange via solid plates does not occur, and the cooling performance can be further enhanced.

Also in the case of this example, as in the first example, the method of forming such a vacuum double tube structure is not particularly limited.

In the example of FIG. 7, as in the example of FIG. do. As a result, the space 583 can be easily evacuated, and there is no risk of vacuum deterioration. Also in this example, as shown in FIG. 4, by further providing a radiant heat shield 587 on the outer side of the outer tube 582 to shield the radiant heat, the cooling performance can be further enhanced.

[Third example of heat insulation structure of stage support part]
FIG. 8 is a perspective view showing a third example of the heat insulation structure of the stage support portion 58. As shown in FIG.
In this example, a pair of flanges 588a and 588b are provided at the upper and lower ends of the inner tube 581, and a plurality of shafts 589 are arranged at equal intervals outside the inner tube 581 so as to connect the flanges 588a and 588b. At this time, since the stage support portion 58 is provided in a vacuum, the space between the inner tube 581 and the shaft 589 is also vacuum, and vacuum heat insulation can be realized. Further, by using the shaft 589 on the outer side, the strength (rigidity) can be secured, the heat conduction path can be reduced, the heat resistance can be increased, and the cooling performance can be further improved.

Further, as shown in FIG. 9, a configuration in which a radiant heat shield 587 is further provided on the outside of the inner tube 581 can be employed. Thereby, the radiant heat from the outside can be shielded, and the cooling performance can be improved.

[Fourth example of heat insulation structure of stage support part]
FIG. 10 is a cross-sectional view showing a fourth example of the heat insulation structure of the stage support portion 58. As shown in FIG.
In this example, similar to the second example in FIG. It is different from the second example in that a bent portion 582a like a multi-step fold is formed. In this example, the bent portion 582a is formed in the reduced diameter portion 58c of the main body portion 58a, but the formation position of the bent portion 582a is not limited.

By forming the bent portion 582a such as a bellows in the outer tube 582 in this manner, the heat resistance can be increased, and the heat insulating effect can be further enhanced. The heat resistance can be adjusted to a desired value by adjusting the size and number of bends of the bend 582a.

A similar effect can be obtained by forming a bent portion in the inner tube 581 . Also, by forming the bent portion formed in the inner tube 581 as a bellows, it is possible to impart a function of relieving thermal stress against temperature changes from normal temperature to extremely low temperature.

<Operation of processing device and action/effect of stage device>
In the processing apparatus 1, the inside of the vacuum vessel 10 is brought into a vacuum state, and the refrigerator 52 of the stage device 50 is operated. Also, the first cooling gas is supplied to the gap G through the first cooling gas flow path 54a.

Then, the stage device 50 is moved (lowered) by the lifting mechanism 74 so that the stage 56 is at the transfer position, and the wafer W is transferred from the vacuum transfer chamber to the vacuum vessel 10 by a transfer device (none of which is shown). and placed on the stage 56 . Next, a DC voltage is applied to the chuck electrode 56b, and the wafer W is electrostatically attracted by the electrostatic chuck 56a.

Thereafter, the lifting mechanism 74 moves (raises) the stage device 50 so that the stage 56 is at the processing position, and adjusts the inside of the vacuum chamber 10 to an ultra-high vacuum (for example, 10 ⁻⁵ Pa or less), which is the processing pressure. . Then, the driving mechanism 68 is driven to transmit the rotation of the rotor 68a to the stage 56 via the rotating body 66a, the rotating portion 62a, and the stage support portion 58. rotate with respect to

At this time, in the stage device 50 , the stage 56 is separated from the fixedly provided refrigerating heat transfer element 54 , so the stage 56 is rotated by the drive mechanism 68 via the stage support section 58 . be able to. Cold heat transferred from the cryogenic refrigerator 52 to the refrigerating heat transfer element 54 is transferred to the stage 56 via the first cooling gas supplied to the narrow gap G of 2 mm or less. By sucking the wafer W with the electrostatic chuck 56 a while supplying the second cooling gas to the rear surface of the wafer W, the wafer W can be efficiently cooled by the cold heat of the stage 56 . Therefore, it is possible to rotate the wafer W together with the stage 56 while maintaining the wafer W at an extremely low temperature of -30.degree.

At this time, a comb tooth portion is formed between the first heat transfer portion 56c of the stage 56 and the second heat transfer portion 54b of the refrigerating heat transfer member 54, and the gap G is bent. to the stage 56 is highly efficient.

With the wafer W rotated in this manner, a voltage is applied to the target 30 from a power supply for plasma generation (not shown) while introducing a sputtering gas into the vacuum chamber 10 . Thereby, plasma of the sputtering gas is generated, and the target 30 is sputtered by ions in the plasma. Atoms or molecules of the sputtered target material are deposited on the surface of the wafer W held in a cryogenic state by the stage device 50 to form a desired film, for example, a magnetic film for a TMR element having a high magnetoresistance ratio. can be membrane.

When a cooling device and a film forming device are provided separately as in Patent Document 1, it is difficult to maintain high cooling performance, and the number of devices increases. On the other hand, in Patent Literature 2, the substrate can be cooled to an extremely low temperature using a cooling head cooled by a refrigerator in the film formation container, but uniform film formation is difficult because the stage is fixed.

On the other hand, in the present embodiment, the stage 56 and the refrigerating heat transfer body 54 for transferring the cold heat of the refrigerator 52 kept at cryogenic temperature are provided separately through the gap G, and heat is transferred to the gap G. A cooling gas is supplied for the stage, and the stage is configured to be rotatable via the stage support portion 58 . Accordingly, it is possible to achieve both high cooling performance for the wafer W and uniformity of film formation.

Further, for example, when forming a magnetic film for a TMR element, the wafer W may be transported to the stage 56 at a high temperature of 100 to 400.degree. Then, it is necessary to cool the wafer W in such a high temperature state to an extremely low temperature of -223 to -23°C (50 to 250K), for example -173°C (100K). In this case, due to the large heat input from the wafer W, in order to efficiently cool the wafer W to an extremely low temperature, it is necessary to reduce the heat input from outside other than the wafer W as much as possible to improve the cooling performance. .

Therefore, in the present embodiment, the stage support member 58, which is in direct contact with the stage 56 and receives heat input from a heat generating portion such as a magnetic fluid seal, has a heat insulating structure to suppress the heat input from the stage support member 58 to the stage 56. and keep the cooling performance high. For this reason, the cooling efficiency via the refrigerating heat transfer body 54 is increased, the cooling time is shortened, and the consumption of the first cooling gas can be suppressed. can be realized.

At this time, by making the heat insulating structure of the stage support portion 58 based on vacuum heat insulation as shown in the above-described first to fourth examples, the heat input from the heat generating portion to the stage 56 can be effectively controlled. can be suppressed, and the cooling performance can be enhanced.

Moreover, by using the radiant heat shield 587 as described above, heat input due to radiant heat from the outside can be suppressed, and the cooling performance can be further improved.

Furthermore, since the first cylindrical heat insulating structure 70 having a vacuum double-tube structure is provided so as to cover the lower portions of the refrigerator 52 and the refrigerating heat transfer body 54, the cold head portion of the refrigerator 52, which is important for cooling, is provided. It is possible to suppress deterioration in cooling performance due to heat input from the outside to the lower portion of 52a and refrigerating heat transfer body 54 .

In addition, since the second heat insulating structure 71 having a cylindrical shape with a vacuum double tube structure whose inside is evacuated is provided so as to cover the entire refrigerating heat transfer body 54, heat from the outside is transferred to the refrigerating heat transfer body. A decrease in cooling performance due to heat input to 54 can be suppressed.

<Other applications>
Although the embodiments have been described above, the embodiments disclosed this time should be considered as examples and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

For example, the heat insulation structure of the stage support is not limited to the first to fourth examples. Further, in the above-described embodiment, the case of application to the sputter deposition of the magnetic film used for the TMR element has been described as an example, but the present invention is not limited to this as long as it requires uniform processing at an extremely low temperature.

1; processing device 10; vacuum vessel 30; target 50; stage device 52; first heat transfer section 58; stage support section 58a; body section 58c; reduced diameter section 62; seal rotation mechanism 64; bellows 68; inner tube 582; outer tube 582a; bent portion 583; internal space 584, 585; horizontal portion 586; substrate to be processed)

Claims (16)

a stage for holding the substrate to be processed within the vacuum chamber;
a refrigerating heat transfer body fixedly arranged on the back side of the stage with a gap from the stage and cooled to an extremely low temperature by a refrigerator;
a cooling fluid for transferring cold heat of the refrigeration heat transfer body to the stage, which is supplied to the gap;
a cylindrical stage support part that rotatably supports the stage, covers the upper part of the refrigeration heat transfer body, and has a vacuum insulation structure;
a rotating part that supports the stage supporting part and is rotationally driven by a driving mechanism in a state sealed with a magnetic fluid;
with
a body portion of the stage support portion has a double-tube structure consisting of an inner tube and an outer tube, and an internal space between the inner tube and the outer tube is held in a vacuum;
The stage support section is arranged in a vacuum space communicating with the vacuum vessel, the outer tube has a plurality of through holes, and the internal space communicates with the vacuum space through the through holes to create a vacuum. A stage device that is regarded as a space . 2. The stage apparatus according to claim 1 , wherein said body portion of said stage support portion has a reduced diameter portion, and a horizontal portion corresponding to said reduced diameter portion is made of a solid plate. 2. The stage device according to claim 1, wherein said body portion of said stage support portion has a reduced diameter portion, and said body portion as a whole has said double pipe structure. 4. The stage apparatus according to any one of claims 1 to 3 , wherein said outer tube has a bent portion formed by bending. 5. The stage device according to claim 1 , wherein said body portion of said stage support portion further includes a radiation heat shield provided outside said outer tube. 6. The stage device according to claim 1, wherein said stage has an electrostatic chuck that electrostatically attracts said substrate to be processed. The cooling fluid supplied to the gap is a first cooling gas, and the first cooling gas flows through a first cooling gas flow path provided in the refrigeration heat transfer body and is supplied to the gap. 7. The stage device according to claim 6 . 7. A second cooling gas for heat transfer is supplied between the substrate to be processed and the electrostatic chuck through a second cooling gas flow path different from the first cooling gas flow path. The stage device according to claim 7 . 8. The stage according to claim 6 , wherein the first cooling gas is supplied between the substrate to be processed and the electrostatic chuck through a channel that communicates with the first cooling gas channel. Device. 2. A first heat insulating structure having a vacuum heat insulating structure, which is provided in a cylindrical shape so as to cover at least a cold head portion of the refrigerator and a connection portion of the refrigerating heat transfer body with the cold head portion, further comprising a first heat insulating structure. 10. The stage apparatus according to any one of claims 9 to 10. 11. The stage device according to claim 10 , further comprising a second heat insulating structure having a vacuum heat insulating structure, which is provided in a cylindrical shape so as to cover the heat transfer member for refrigeration. Between the stage supporting portion and the second heat insulation structure, there is a space sealed with a sealing member into which the first cooling gas leaking from the gap flows, and a gas flow path is connected to the space. and the gas passage has a function of discharging the first cooling gas in the space from the space, or a function of supplying a third cooling gas, which is a counterflow of the first cooling gas, into the space. 12. The stage device according to claim 11 . 13. The stage device according to any one of claims 1 to 12 , wherein the connecting portion between the stage and the refrigerating heat transfer body has a comb tooth portion that makes the gap uneven. a vacuum vessel;
a stage device according to any one of claims 1 to 13 for rotatably holding a substrate to be processed within the vacuum vessel;
a processing mechanism for processing a substrate to be processed within the vacuum vessel;
a processing device. 15. The processing apparatus according to claim 14 , wherein said processing mechanism has a target for sputtering film formation disposed above said stage within said vacuum chamber. 16. The processing apparatus according to claim 15 , wherein said target is made of a material for forming a film of a magnetic material used for a tunnel magnetoresistive element.

Images