Stage device and charged particle beam apparatus including the same

Abstract

To provide a stage device that makes it possible to prevent thermal deformation of a stage and improve positional accuracy in positioning of the stage even with a configuration in which a Peltier element is arranged on a fixed-side stage, and a charged particle beam apparatus including the same.SOLUTION: A stage device comprises a first stage that linearly moves, a first fin extending in a direction in which the first stage linearly moves and having a comb-tooth-shaped cross-sectional shape, a second stage that includes a second fin disposed to face the first fin and is fixed as viewed from the first stage, a heat transfer mechanism that performs heat transfer while maintaining a non-contact relationship between the first fin and the second fin, and a Peltier module provided between the second fin and the second stage. One heat transfer surface of the Peltier module is in contact with the second fin, and the other heat transfer surface is in contact with the second stage. The stage device further comprises a control part that controls a temperature of the second fin by the Peltier module. There is also provided a charged particle beam apparatus including the stage device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stage device and a charged particle beam device equipped with the same. [Background technology]

[0002] The integration density of semiconductor products is increasing year by year, and their circuit patterns are becoming finer and finer. Various inspection methods are used for semiconductor wafers on which circuit patterns are formed, for the purposes of quality control and yield improvement. One of these methods is a technology that uses a scanning electron microscope to photograph semiconductor wafers and then inspect the circuit patterns from the obtained images.

[0003] In specimens such as semiconductor wafers, circuit patterns are formed at high density, and therefore a particularly high degree of positional accuracy is required in stage devices for scanning electron microscopes.

[0004] One method for improving the positioning accuracy of stage devices is to use a levitation stage to prevent vibration propagation and prevent vibration-related positioning errors. However, because stage devices for scanning microscopes are used in a vacuum, using a levitation stage makes it difficult to dissipate heat from the stage. Without heat dissipation, heat generated within the stage changes the stage temperature, resulting in thermal deformation and reduced positioning accuracy. Patent Document 1, therefore, describes a technology for improving positioning accuracy by actively cooling the levitation stage. Patent Document 1 describes a technology for suppressing stage temperature rise and preventing thermal deformation, thereby improving positioning accuracy. It creates a blackbody surface for a magnetically levitated stage in a vacuum, places a radiation plate in a non-contact state on the blackbody surface, and further cools the back of the radiation plate using Peltier elements. The opposite side of the Peltier element is then cooled by a cooling plate to suppress thermal deformation of the stage. Patent Document 1 also describes another embodiment in which Peltier elements are placed above the magnetically levitated stage, which are then divided and arranged on a flat surface. The Peltier elements are driven according to the planar position of the stage for effective cooling.

[0005] On the other hand, radiative heat transfer (radiation heat transfer) generally has weaker heat transfer properties than solid thermal conduction. Therefore, given the same temperature difference, radiative heat transfer tends to result in a smaller heat flux than solid thermal conduction. Patent Document 2 (Patent Document 2) addresses this issue. In Patent Document 2, to increase the surface area for radiative heat transfer, comb-shaped fins are arranged facing each other, and radiative heat transfer occurs between the fins, increasing the heat transfer area per space. Furthermore, these fins extend in the direction of stage movement, preventing interference between the fins even when the stage moves. Patent Document 2 also discloses placing a Peltier element on the side of a stage that moves relative to a fixed side. When a Peltier element is placed on the fixed side of a moving stage, the relative positional relationship between the Peltier element and the moving stage constantly changes. However, when the Peltier element is placed on the moving stage, the relative positional relationship is fixed and maintained. This means that the relative position of the Peltier element remains constant no matter how much the stage moves, which is a significant advantage in stage temperature control. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-058258 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-351741 Summary of the Invention [Problem to be solved by the invention]

[0007] When a Peltier element is placed on the side of the moving stage, as in Patent Document 2, the amount of heat required to operate the Peltier element must also be transferred to the fixed side by radiative heat transfer. On the other hand, when the Peltier element is placed on the fixed side, as in Patent Document 1, there is no need to radiatively transfer the amount of heat required to operate the Peltier element. Therefore, the method of placing a Peltier element on the side of the moving stage has the disadvantage of a greater load on radiative heat transfer compared to the method of placing a Peltier element on the fixed side.

[0008] Furthermore, when a Peltier element is placed on the fixed side as in Patent Document 1 and comb-shaped fins are used facing each other as in Patent Document 2, a problem arises in that it becomes difficult to properly control the stage temperature due to the time delay that occurs when the temperature of the fins changes.

[0009] In a typical device, the time it takes for a stage to move from one location to the next is not very long. When a Peltier element is placed on the fixed side, a control system must ensure that the Peltier element located at the new location cools the stage when the stage moves. However, when the Peltier element cools the fins and increases the temperature difference between the opposing fins to increase radiative heat transfer and cool the stage, there is a time delay, due to the thermal capacity of the fins, between the time the Peltier element increases its heat absorption and the time the temperature of the cooled fins drops. Therefore, even if the Peltier element increases its heat absorption and lowers the fin temperature after the stage moves, by the time the fin temperature drops enough to cool the stage, the stage moves to the next location, resulting in an inability to properly cool the stage. This problem is not a problem when a Peltier element is placed on the moving side, as in Patent Document 2, because the Peltier element follows the stage movement. However, this configuration has the problem of a greater radiative heat transfer load compared to a system where a Peltier element is placed on the fixed side.

[0010] If fins are not used, as in Patent Document 1, and the heat absorption surface of the Peltier element is used as the radiative heat transfer surface, the amount of heat absorbed from the stage changes immediately when the current to the Peltier element is changed, so the delay described above does not pose a problem. However, with a method in which the Peltier element is placed on the fixed side and comb-tooth fins are used, the time delay in the temperature control system is large compared to the time interval for the stage to move, which presents a unique problem in that it is difficult to control the temperature of the stage.

[0011] The object of the present invention is to provide a stage device that can reduce the load on stage cooling due to radiative heat transfer, thereby increasing efficiency, prevent thermal deformation by preventing changes in stage temperature over time, and improve the positioning accuracy of the stage, as well as a charged particle beam device equipped with the same. [Means for solving the problem]

[0012] The present invention has the following configuration to achieve the above object.

[0013] The stage device includes a first stage that moves linearly, a first fin with a comb-like cross section extending in the direction of linear movement of the first stage, a second fin positioned opposite the first fin, and a second stage that is fixed relative to the first stage. The stage device also includes a heat transfer mechanism that transfers heat between the first fin and the second fin while maintaining a non-contact relationship. The stage device also includes a Peltier module between the second fin and the second stage, one heat transfer surface of the Peltier module contacting the second fin and the other heat transfer surface contacting the second stage. The Peltier module controls the temperature of the second fin, thereby controlling the heat transfer between the second fin and the first fin on the first stage. Furthermore, the second stage includes multiple Peltier modules arranged in the direction of movement of the first stage. By controlling the multiple Peltier modules, the temperature of the second fin is made uniform, thereby ensuring uniform heat transfer regardless of where the first stage moves. A charged particle beam device also includes the stage device. [Effects of the Invention]

[0014] By placing a Peltier element on the fixed stage, the load on radiative heat transfer is reduced, and the increased surface area of ​​the fins increases the heat transfer capacity. Furthermore, the problem of delays in temperature control caused by the heat capacity of the fins is solved, and by preventing changes in stage temperature over time, thermal deformation of the stage can be prevented, making it possible to provide a stage device and a charged particle beam device equipped with the same that can increase the positioning accuracy of the stage. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a view of the stage device of the first embodiment, viewed in a direction opposite to the movement of the levitation stage. [Figure 2] FIG. 2 is a diagram of the stage device of the first embodiment, viewed from the side to show the movement of the levitation stage. [Figure 3] FIG. 10 is a diagram of a stage device and a system according to a second embodiment. [Figure 4] FIG. 10 is a diagram of a stage device and a system according to a third embodiment. [Figure 5] FIG. 10 is a diagram showing a stage device and a system according to a fourth embodiment. [Figure 6] FIG. 10 is a diagram showing a stage device and a system according to a fifth embodiment. [Figure 7] FIG. 13 is a diagram showing a stage device and a system according to a sixth embodiment. [Figure 8] FIG. 13 is a diagram showing a stage device and a system according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Example]

[0017] The configuration and system of a stage device according to a first embodiment of the present invention are shown in Figures 1 and 2. Figures 1 and 2 show the same device, but are viewed from a different angle by 90 degrees.

[0018] In this stage device, upper stage 1 is a floating stage and lower stage 2 is a guide rail type stage. In FIG. 1, upper stage 1 (also referred to as the "floating stage" or "first stage") moves in the depth direction of the page, and this direction of movement is indicated by arrow 100. Lower stage 2 (also referred to as the "second stage") moves in the direction of arrow 101. In FIG. 2, upper stage 1 moves in the direction indicated by arrow 100, and lower stage 2 moves in the depth direction of the page.

[0019] The upper stage 1 is driven by an upper-stage linear motor, which is composed of a coil assembly 46 as a mover and a magnet assembly 47 as a stator. Passing a current through the coil assembly 46 in the magnetic field formed by the magnet assembly 47 generates a thrust, which is then transmitted to the upper stage 1, causing the upper stage 1 to move in the direction of arrow 100. Driving the stage in this manner generates heat due to the current flowing through the coil assembly. That is, a coil always has electrical resistance, and Joule heat is generated in proportion to the product of the electrical resistance and the square of the current flowing therethrough. Because the coil assembly 46 must transmit thrust to the upper stage 1, the two must be connected. Joule heat from the coil assembly 46 is transmitted to the upper stage 1, raising its temperature. Note that Figures 1 and 2 omit the illustration of mechanisms for levitating the upper stage 1, for measuring the stage position, and for driving the lower stage 2.

[0020] As shown in Figure 1, heat dissipation fins 5 (also referred to as "first fins") are attached to the bottom surface of the levitation stage 1. The heat dissipation fins 5 have a comb-like cross section and extend in the depth direction of the levitation stage 1 while maintaining the same cross-sectional shape. Heat absorption fins 6 (also referred to as "second fins"), which will be described later, also have a comb-like cross-sectional shape. The tips of the comb teeth of both fins face each other, and the comb teeth fit into the gaps between each other. This arrangement allows most of the surface area of ​​both fins to face each other.

[0021] Solid surfaces emit heat proportional to the fourth power of the absolute temperature, and when exposed to heat radiation, they have the property of absorbing or reflecting the energy of the heat radiation. The rate at which a solid surface absorbs radiant heat is called emissivity, which is equal to the rate at which actual heat radiation occurs compared to the heat emitted by a blackbody. Therefore, it is desirable to have high surface emissivity for the heat dissipation fins 5 and heat absorption fins 6. In the heat dissipation fin 5, as heat is released from the fin surface, the temperature decreases from the base of the comb teeth to the tip. Therefore, a material with high thermal conductivity is preferable for the fins. Furthermore, for stages that move repeatedly, lighter parts reduce inertial forces and vibration. For this reason, the lower the density (specific gravity) of the fin material, the better. Aluminum has high thermal conductivity and low density, and A6063 and A6061 are particularly suitable for fins. However, because aluminum generally has low emissivity, it is preferable to use a surface treatment to increase emissivity when forming fins from aluminum. Additionally, aluminum surfaces are generally treated with anodizing to improve corrosion resistance. It is even better to apply a special anodizing treatment to both the heat dissipation and absorption fins, which can improve emissivity.

[0022] The heat absorption fins 6 are connected to the lower stage 2 via (sandwiched between) a Peltier module 7. It is preferable that the heat absorption fins 6 are not in direct contact with the lower stage 2 so that the temperature of the heat absorption fins 6 can be controlled more precisely by the Peltier module 7 (also referred to as the "first Peltier module"). The Peltier module 7 generally has many Peltier elements arranged on an electrically insulating plate, these elements connected by an electrical circuit, and both the top and bottom surfaces are made of insulating plates, so that one of the top and bottom surfaces serves as a heat absorption surface and the other as a heat dissipation surface.

[0023] In this embodiment, the upper surface of the Peltier module 7 is a heat absorption surface that cools the heat absorption fins 6. The lower surface of the Peltier module 7 is a heat dissipation surface, and by bringing this surface into contact with the lower stage 2, the heat exhausted from the Peltier module 7 is transferred to the lower stage 2. The law of conservation of energy always holds when the Peltier module 7 is operating. Therefore, the heat dissipation amount is the sum of the heat absorption amount and the power consumption (= power supply) of the Peltier module. Therefore, heat cannot be absorbed without heat dissipation. Therefore, cooling the heat absorption fins 6 using the Peltier module 7 can only be achieved by dissipating heat to the lower stage 2. The lower stage 2 transfers the heat received from the Peltier module 7 to the guide rail 3 via the slide unit 8, and the heat is transferred to the base 4 of the stage device. When this stage device is installed inside a vacuum chamber, the base 4 often serves as the vacuum chamber.

[0024] To efficiently cool the levitation stage using the heat absorption fins 6, it is preferable that the heat absorption fins 6 only absorb radiant heat transferred from the heat dissipation fins 5 and not receive heat transferred from other sources. One way to achieve this is to have the fins on both ends of the heat absorption fins 6 covered by the heat dissipation fins (for example, in the configuration of Figure 1, the number of fins on the heat dissipation fins 5 should be one more than the number of fins on the heat absorption fins 6). In this way, it is possible to prevent the heat absorption fins 6 from absorbing heat from other sources and placing an unnecessary load on the Peltier module 7.

[0025] Furthermore, the backside of the base of the teeth of the comb-like heat-absorbing fins 6 faces the lower stage 2. It is better that the heat-absorbing fins 6 do not receive radiant heat from the lower stage 2, and it is better that the emissivity of the backside of the heat-absorbing fins 6 is low.

[0026] If the heat absorption fins 6 are made of aluminum, it is best to perform a surface treatment to improve emissivity only on the front surface of the fins, leaving the rear surface exposed as the aluminum base material with high reflectivity. Also, even in a structure in which both the heat absorption fins 6 and the Peltier module 7 are fixed to the lower stage 2, it is best to use a structure that suppresses heat conduction.

[0027] When the heat absorption fin 6 is attached in a state of sandwiching the Peltier module 7 so as to be pressed against the lower stage 2 by bolts, a pressing pressure is applied to the heat transfer surface, which is preferable. However, if the thermal conductivity of the bolts is high, heat flows from the lower stage 2 toward the low-temperature heat absorption fin 6, and accordingly, the cooling load of the Peltier module increases. For this reason, it is preferable to use a material with a low thermal conductivity such as a resin material for the bolts for attaching the heat absorption fin 6 to the lower stage while sandwiching the Peltier module 7.

[0028]

[0029] In addition, a control method may be used that takes into account the delay time from when the current flowing through the Peltier module 7 is changed until the temperature of the heat absorption fin 6 changes and then until the temperatures of the heat radiation fin 5 and the floating stage body 1 change. Those control operations are performed by a controller 11 (also referred to as a "control unit" or a "controller").

[0030] To keep the temperature of the floating stage 1 constant at the target temperature state, while measuring the temperature with a temperature measurement unit (not shown), a command is sent to the power supply unit 10 that is passing an electric current through the Peltier module 7, and it is preferable to perform feedback control on the cooling capacity of the Peltier module 7. Assuming that the measured temperature of the floating stage 1 is Ts and the target temperature is Ts', when Ts > Ts', the current flowing through the Peltier module 7 is increased to increase the cooling capacity. Conversely, when Ts < Ts', the current flowing through the Peltier module 7 is decreased to reduce the cooling capacity. Furthermore, to enhance this control operation, it is preferable to introduce PID control. That is, it is a method of determining the current flowing through the Peltier module 7 based on the sum of three variables: the value of Ts - Ts', the time differential value of that value, and the time integral value of that value, with proportional coefficients (= weightings) provided for each of the three variables.As shown in Figure 2, when the movement of the levitation stage 1 is viewed from the side, in this embodiment three Peltier modules 7 are lined up in the direction of movement of the levitation stage 1. The arrangement of three here is just one example, and the number can be changed as needed. In order for the levitation stage 1 to move around, a range of movement larger than the size of the main body 1 is set, and in order to demonstrate cooling capacity anywhere within that range of movement, it is best to line up multiple Peltier modules in the direction of stage movement.

[0031] In this way, when using multiple Peltier modules, in this embodiment the electrical circuit for supplying current is configured as a parallel circuit, and the same voltage (V) is applied to all Peltier modules. The purpose of applying the same voltage is to make the temperature of the heat absorption fins 6 uniform in the direction of movement of the levitation stage 1. Note that although Fig. 2 shows the heat absorption fins 6 divided into separate Peltier modules, the entire heat absorption fin 6 may also be manufactured as a single unit.

[0032] Manufacturing it as a single unit has the advantage of uniforming the temperature throughout due to the thermal conduction of the solid. On the other hand, when lowering the temperature of the heat-absorbing fins in particular, the temperature difference becomes larger compared to the other parts, causing the heat-absorbing fins to thermally shrink significantly, resulting in thermal stress. Separating the heat-absorbing fins 6 for each Peltier module has the advantage of reducing this thermal stress.

[0033] As shown in Figure 2, if the levitation stage 1 stays biased toward the left side of its range of movement for a long time, it will mainly exchange heat with the heat-absorbing fin 6 on the left side. In other words, the heat generated by the levitation stage 1 is transferred to the heat-absorbing fin 6 via the heat-dissipating fin 5, but since radiation heat transfer occurs mainly where the fin surfaces face each other, the heat-absorbing fin 6 is only subjected to a thermal load where the heat-dissipating fin 5 is located. Even so, if the temperature of the levitation stage 1 is measured and the cooling capacity of the Peltier module is fed back and controlled, it is possible to bring the levitation stage 1 to the target temperature. However, this is only the case when the levitation stage 1 stays in the same place for a long time; the story is different if the levitation stage 1 moves around.

[0034] If the levitation stage 1 stays biased toward the left side of its range of motion for a long time and multiple Peltier modules are operated with the same cooling capacity, the levitation stage 1 will be maintained at the target temperature, but the heat-absorbing fins 6 in areas where the levitation stage is not present will not be subjected to thermal load and will become overcooled. In other words, the heat-absorbing fins 6 on the right side of Figure 2 will be cooler than those on the right side. This is fine when the levitation stage 1 is not on the right side, but if it suddenly moves to the right side, the levitation stage will become overcooled. If an overcooling state of the levitation stage 1 is detected, the cooling capacity of the Peltier module can be reduced, but this will result in a time delay, which will inevitably result in a temporary drop in the temperature of the levitation stage. This can be prevented by supplying current to multiple Peltier modules in a parallel circuit, as shown in Figure 2.

[0035] The principle behind this is explained using the equations for the operating characteristics of the Peltier module. The variables used in the equations are listed in Table 1.

[0036] [Table 1]

[0037] First, equation (1) shows the heat absorption amount [W] of the Peltier module.

[0038]

number

[0039] The heat absorption effect of a Peltier module occurs in proportion to the current flowing through it, and the proportionality coefficient can be expressed using the Seebeck coefficient and the absolute temperature of the heat absorption surface. Meanwhile, the temperature difference between the heat dissipation surface and heat absorption surface of the Peltier module, expressed by equation (3), causes thermal conduction, reducing the amount of heat absorbed by the Peltier module.

[0040]

number

[0041] Furthermore, the electrical resistance of the Peltier module generates Joule heat according to the current flowing through it, and half of that heat flows to the heat absorption surface and half to the heat dissipation surface. Meanwhile, the first term on the right-hand side of equation (2) regarding the heat dissipation amount of the Peltier module indicates the effect of the current, and its proportionality coefficient is determined by the Seebeck coefficient and the absolute temperature of the heat dissipation surface.

[0042]

number

[0043] The difference in coefficients for current between the amount of heat absorbed and the amount of heat released comes from the Seebeck effect, which can be described by equation (4), and is a phenomenon in which thermoelectric power is generated in proportion to the temperature difference between the heat-releasing surface and the heat-absorbing surface.

[0044]

number

[0045] Due to this Seebeck effect, the voltage across the Peltier module is expressed as equation (5).

[0046]

number

[0047] In other words, the voltage generated by multiplying current by electrical resistance and the thermoelectric power due to the Seebeck effect sum to form the voltage when current flows through a Peltier module. Incidentally, the power (= power consumption) supplied to a Peltier module is the same as a normal DC current load, and can be calculated by multiplying voltage by current. Furthermore, the law of conservation of energy, which states that the difference between the amount of heat dissipated and absorbed is the power consumption, is established in the equations for the main body system, and the relationship in equation (6) can be confirmed by taking the difference between equations (2) and (1).

[0048]

number

[0049] As explained in the mathematical formula for this system, in a Peltier module, a thermoelectromotive force (= voltage) is generated in proportion to the temperature difference between the heat dissipation surface and the heat absorption surface. As already explained, in the arrangement shown in Figure 2, the levitation stage 1 is positioned to the left, which means that the heat absorption fins on the right side are not subjected to a thermal load, making them prone to becoming too cold. In this case, the heat absorption surface temperature of the Peltier module on the right side will be lower than that of the other Peltier modules. In this case, the temperature difference between the heat dissipation surface temperature and the heat absorption surface temperature of the Peltier module on the right side will be greater. This means that the thermoelectromotive force due to the Seebeck effect will be greater than that of the other Peltier modules.

[0050] When the same voltage is applied to all Peltier modules, if the thermoelectric power of one Peltier module increases, the voltage (current multiplied by electrical resistance) decreases accordingly. This voltage decrease means that the current flowing through the Peltier module decreases. Therefore, when the same voltage is applied to multiple Peltier modules, if one Peltier module experiences a decrease in heat absorption surface temperature and an increase in thermoelectric power, the current flowing through that Peltier module will be lower than the others. This will reduce the cooling effect of the Peltier module, causing the Peltier module's heat absorption surface temperature to increase. Therefore, applying the same voltage to multiple Peltier modules tends to align the heat absorption surface temperatures, which in turn aligns the heat absorption fin temperatures. Therefore, supplying current via a parallel circuit to multiple Peltier modules aligned in the direction of levitation stage 1 movement will result in a more uniform heat absorption fin temperature along the direction of levitation stage 1 movement.

[0051] If the heat absorption fins reach a uniform temperature in the direction of movement of the levitation stage 1, the same cooling capacity will be obtained no matter where the levitation stage 1 is located. Therefore, even if the levitation stage 1 remains in one location for a long period of time and then moves to another location, the temperature of the levitation stage 1 can be kept constant. Furthermore, using the control principle explained using Figure 1, even if the average heat generation amount of the levitation stage 1 changes, the temperature of the levitation stage 1 can be kept constant through feedback control. [Example]

[0052] 3 shows the configuration and system of a stage device in a second embodiment of the present invention. In the following explanation, parts with the same functions will be given the same reference numerals, and explanations will be omitted.

[0053] The embodiment in FIG. 3 differs from the first embodiment in that, rather than applying the same voltage to multiple Peltier modules 7 using a single power supply unit, individual power supply units 12-14 are provided for each Peltier module. Having a one-to-one correspondence between Peltier modules and power supply units makes it possible to determine the thermoelectromotive force generated in each Peltier unit. In other words, if power supply unit 12 supplies power with a current I1 and a voltage V1, the thermoelectromotive force Vz1 of that Peltier module can be calculated using equation (5). The same applies to power supply units 13 and 14.

[0054] Meanwhile, when controlling the temperature of the levitation stage 1 with this configuration, the controller 18 determines the target thermoelectromotive force Vz by looking at the difference between the measured temperature Ts and the target temperature Ts'. This target thermoelectromotive force is given as the same target value to all Peltier modules. Then, each power supply unit 12-14 controls the current so that the thermoelectromotive force in the operating state reaches the target value. When such current control is performed, the thermoelectromotive force of all Peltier modules becomes the same, and temperature uniformity can be achieved with greater precision than in the first embodiment. This reduces temperature change in the levitation stage 1, further reducing thermal deformation and improving positional accuracy. [Example]

[0055] FIG. 4 shows the configuration and system of a stage device according to a third embodiment of the present invention. In this embodiment, the temperature of the heat-absorbing fin for each Peltier module is measured. The current of each Peltier module is controlled based on the difference between the measured temperature of each heat-absorbing fin and the target temperature of the heat-absorbing fin. In this case, controllers 19-21 are provided to determine the current of each Peltier module. To control the temperature of the levitation stage 1, controller 22 determines the target temperature of the heat-absorbing fin. The target fin temperature determined by controller 22 is used to operate each of the individual controllers 19-21. PID control is also an effective method for the controllers 19-21. The controllers 19-21 determine the output current of each of the power supply units 15-17 for the Peltier modules, simplifying the internal configuration. [Example]

[0056] Figure 5 shows the configuration and system of a stage device in a fourth embodiment of the present invention. In this embodiment, a cooling system for the lower stage is added to the configuration of the first embodiment. The cooling system for the levitation stage 1 is the same as in the first embodiment, so a description thereof will be omitted here. Note that the cooling structure for the lower stage shown here may be combined with the cooling system of the levitation system in the second and third embodiments.

[0057] To assist in cooling the lower stage, in this embodiment, heat dissipation fins 23 (also referred to as "third fins") are attached to the bottom surface of the lower stage 2. These heat dissipation fins 23 have a comb-like cross section and extend in the direction of movement of the lower stage 2. Heat absorption fins 24 (also referred to as "fourth fins") are provided opposite the heat dissipation fins 23, and are attached to the base 4 with a Peltier module 25 (also referred to as "second Peltier module") sandwiched between them. As with the first embodiment, when this stage device operates in a vacuum environment, the base 4 refers to the vacuum container. A plurality of Peltier modules 25 are arranged in the direction of movement of the lower stage 2, and power is supplied via a parallel circuit.

[0058] When operating the Peltier module 25 for cooling the lower stage, it is preferable that the controller 26 grasps the temperature measured by a temperature measurement unit (not shown) provided on the lower stage 2, applies feedback so that this becomes the target temperature for the lower stage, and controls the voltage for passing current through the Peltier module 25.

[0059] Actively controlling the temperature of the lower stage 2, as in this embodiment, stabilizes the temperature of the lower stage 2. Without active temperature control, if the heat emitted from the Peltier module 7 for the levitation stage 1 increases, the temperature of the lower stage 2 rises, increasing the heat transferred from the slide unit 8 to the guide rail 3, and achieving temperature balance. On the other hand, active temperature control of the lower stage 2 prevents fluctuations in the temperature of the lower stage 2 even if the heat emitted from the Peltier module 7 fluctuates. This stabilizes the temperature of the heat dissipation surface of the Peltier module 7, and the amount of heat absorbed increases simply when the current flowing through the Peltier module is increased. If the temperature of the heat dissipation surface of the Peltier module is unstable, the amount of heat absorbed by the Peltier module not only varies with the current flowing through it, but is also affected by temperature fluctuations on the heat dissipation surface, resulting in poor controllability of the amount of heat absorption. Therefore, actively controlling the temperature of the lower stage 2 to stabilize the temperature improves controllability of the Peltier module 7 for cooling the levitation stage, further contributing to temperature stabilization of the levitation stage 1. Furthermore, the cooling control of the lower stage 2 is solely to control the lower stage 2 to its target temperature, so there is no need to consider the operating conditions of the levitation stage 1. This allows them to operate as independent control systems, preventing interference between the two control systems and causing temperature fluctuations. [Example]

[0060] 6 shows the configuration and system of a stage device according to a fifth embodiment of the present invention. This embodiment also describes an additional cooling system for the lower stage 2, so the cooling system for the combined floating stage may be any of the first to third embodiments.

[0061] To assist in cooling the lower stage, in this embodiment, a Peltier module 27 (corresponding to the "second Peltier module") is first attached to the bottom surface of the lower stage 2, and heat dissipation fins 28 (corresponding to the aforementioned "third fins") are attached to its heat dissipation surface. Furthermore, heat absorption fins 29 (corresponding to the aforementioned "fourth fins") are attached facing the heat dissipation fins 28, and their back surfaces are attached to the base 4. In this embodiment, the Peltier module 27 for cooling the lower stage 2 is attached to the moving side, so there is no need to arrange the Peltier module to cover the entire moving range of the lower stage. The heat absorption surface of the Peltier module 27 is attached to the lower stage main body 2, and it absorbs heat from the lower stage 2 and transfers it to the heat dissipation fins 28. As a result, the temperature of the heat dissipation fins 28 is higher than that of the lower stage 2. Meanwhile, the heat absorption fins 29 are attached to the base 4, so their temperature is approximately the same as that of the base 4. Previous cooling systems used low-temperature heat-absorbing fins to induce radiative heat transfer, but in this embodiment, radiative heat transfer is achieved by heating the heat-dissipating fins to a high temperature when cooling the lower stage. In this method, the Peltier module 27 is attached to the lower stage 2, so even if the lower stage moves, its position relative to the Peltier module remains unchanged, preventing changes in the thermal load. Therefore, even when multiple Peltier modules are used, they do not need to be connected in a parallel circuit; they can be connected in a series circuit. Supplying power in a series circuit increases the voltage supplied from the power supply, but requires less current. Generally, a power supply device can be made smaller with a lower current, so being able to operate with a low current is advantageous.

[0062] In this embodiment, the heat absorbing fins 29 are configured to cover both ends of the heat dissipating fins 28 to prevent radiant heat from returning to the lower stage 2. In the structure shown in Fig. 6, the number of fins in the heat dissipating fins 28 is one more than the number of fins in the heat absorbing fins 29. This configuration prevents heat from returning. It is preferable to apply a surface treatment to the surfaces of the heat dissipating fins 28 and the heat absorbing fins 29 to increase the emissivity, but it is preferable to reduce the emissivity of only the back surface of the heat dissipating fin 28. [Example]

[0063] FIG. 7 shows the configuration and system of a stage device according to a sixth embodiment of the present invention. In this embodiment, cooling of the lower stage is supported passively, without active control. Heat-dissipating fins 31 are attached to the bottom surface of the lower stage 2, with heat-absorbing fins 32 attached opposite them, and the back surface is cooled by a heat sink 33. A coolant flows through the heat sink 33, and the coolant is maintained at a constant temperature at the heat sink inlet and operated at a constant flow rate. Therefore, the cooling capacity of the heat sink 33 is not actively controlled; the amount of heat transfer changes over time only with the change in the temperature of the heat-dissipating fins 31. The lower stage 2 is subjected to a thermal load equal to the sum of the heat generated by the levitation stage 1, the power consumption of the Peltier module 7, and the heat generated by the lower stage 2. Rather than dissipating this heat solely through heat transfer from the slide unit 8 to the guide rail 3, adding a path for dissipating the heat to the heat sink 33 reduces the temperature rise in the lower stage 2, which also contributes to stabilizing the temperature of the floating stage 1.

[0064] Furthermore, the cooling assistance using the heat sink 33 may be used in combination with the fourth and fifth embodiments. [Example]

[0065] Figure 8 shows the configuration and system of a stage device according to a seventh embodiment of the present invention. The difference between this embodiment and the first embodiment is the different lengths of the heat-absorbing fins 6 cooled by the individual Peltier modules 7. In a device in which the proportion of the area occupied by the levitation stage 1 is roughly fixed, the thermal load of the Peltier modules can be equalized by increasing the density of Peltier modules arranged in areas with a high proportion of the area occupied. In the embodiment shown in Figure 8, it is assumed that the levitation stage 1 will spend a high proportion of its movement in the central area. In this case, the thermal load on the central Peltier module will be high. For this reason, the length of the heat-absorbing fins 6' cooled by the central Peltier module is shortened, and the lengths of the heat-absorbing fins 6 on the left and right sides are increased. If the operating pattern of the levitation stage is predetermined and the proportion of the area occupied is known in advance, the hardware can be designed to uniformly distribute the thermal load on the Peltier modules accordingly, thereby aligning the thermal load and achieving uniform temperatures on the heat-absorbing fins. With this configuration, the same cooling capacity can be obtained regardless of the location of the levitation stage 1. In addition, although multiple Peltier modules are connected in a parallel circuit in FIG. 8, it is also possible to supply current in a series circuit. [Explanation of symbols]

[0066] 1 levitation stage (upper stage), 2 lower stage, 3 guide rail for lower stage, 4 base of stage device (vacuum vessel), 5 heat dissipation fin for levitation stage, 6 heat absorption fin for levitation stage, 7 Peltier module for levitation stage (multiple arranged side by side), 8 slide unit that slides on guide rail, 10 power supply unit for supplying current to Peltier module, 11 controller for controlling the temperature of the levitation stage, 12-17 power supply units for supplying current to individual Peltier modules, 18 controller for controlling the temperature of the levitation stage (type via thermoelectric power), 19-21 controllers that determine the current of individual Peltier modules, 22 controller for controlling the temperature of the levitation stage (type via fin temperature), 23 heat dissipation fin for lower stage, 24 heat absorption fin for lower stage, 25 Peltier module for lower stage, 26 controller for controlling the temperature of the lower stage, 27 Peltier module for lower stage (type installed on the stage side), 28 heat dissipation fin for lower stage, 29 heat absorption fin for lower stage, 30 controller for controlling the temperature of the lower stage, 31 heat dissipation fin for lower stage, 32 heat absorption fin for lower stage, 33 heat sink using refrigerant, 100 arrow indicating the direction of movement of the levitation stage, 101 arrow indicating the direction of movement of the lower stage.

Claims

1. a first stage that moves linearly; a first fin having a comb-like cross section extending in the linear movement direction of the first stage; a second stage having second fins arranged opposite to the first fins and fixed when viewed from the first stage; a stage device having a heat transfer mechanism that transfers heat between the first fin and the second fin while maintaining a non-contact relationship between the first fin and the second fin, a first Peltier module is provided between the second fin and the second stage, one heat transfer surface of the first Peltier module contacting the second fin and the other heat transfer surface contacting the second stage; a control unit that controls the temperature of the second fins by the first Peltier module, thereby controlling heat transfer occurring between the second fins and the first fins on the first stage side, A stage device characterized by:

2. 2. The stage device according to claim 1, a plurality of the first Peltier modules provided on the second stage are arranged side by side in the linear movement direction of the first stage; the control unit adjusts the current flowing through each of the plurality of first Peltier modules so that the temperature of the second fins installed on the second stage becomes approximately uniform in the direction of the linear movement of the first stage. A stage device characterized by:

3. 3. The stage device according to claim 2, the control unit controls the temperature of the second fins of the second stage to be approximately uniform by utilizing a thermoelectromotive force generated due to a temperature difference between a heat absorption surface and a heat radiation surface of each of the plurality of first Peltier modules. A stage device characterized by:

4. 4. The stage device according to claim 3, the control unit has a parallel circuit for supplying current to the plurality of first Peltier modules, and controls the plurality of first Peltier modules to be driven at approximately the same voltage. A stage apparatus characterized by:

5. 3. The stage device according to claim 2, a temperature measuring unit that measures the temperature of the first stage; the control unit controls currents flowing through the plurality of first Peltier modules so that the temperature of the first stage measured by the temperature measurement unit becomes a preset target temperature, and controls the temperature of the second fins of the second stage to change. A stage apparatus characterized by:

6. 2. The stage device according to claim 1, the second stage is a lower stage that can move together with the first stage, The movement directions of the first stage and the second stage are approximately perpendicular to each other, so that the first stage can move two-dimensionally. A stage apparatus characterized by:

7. 7. The stage device according to claim 6, the fixing portion as viewed from the second stage has a third fin having a comb-tooth shaped cross section, the fixing portion has a fourth fin facing the third fin, and heat transfer between the third fin and the fourth fin promotes heat transfer of the second stage to the fixing portion. A stage apparatus characterized by:

8. 8. The stage device according to claim 7, a second Peltier module for facilitating heat transfer between the second stage and the fixed portion; the control unit controls the second Peltier module so that the temperature of the second stage becomes a set target temperature. A stage apparatus characterized by:

9. 9. The stage device according to claim 8, the first stage is used in a floating state relative to the second stage, the second stage moves while contacting a guide rail provided on the fixed portion; A stage apparatus characterized by:

10. 10. The stage device according to claim 9, the first stage is a magnetic levitation stage that levitates from the second stage by magnetic force, The first stage is moved linearly by a linear motor, and the linear motor is a moving coil type linear motor. A stage apparatus characterized by:

11. The stage device according to any one of claims 1 to 10 is provided in a housing maintained in a vacuum, the stage device is used to position a sample, and has a charged particle beam irradiation unit that irradiates the sample with a charged particle beam. A charged particle beam device characterized by:

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