The platform device includes its charged particle wire device.

Abstract

[Problem] To provide a platform device that can prevent thermal deformation of the platform even when Peltier elements are arranged on the fixed side of the platform, thereby improving the positioning accuracy of the platform during positioning, and includes a charged particle wire device therein. [Solution] A platform device and a charged particle wire device therein, the platform device comprising: a first platform that moves linearly; a first fin that extends in the direction of linear movement of the first platform and has a comb-shaped cross-section; a second platform having a second fin arranged opposite to the first fin and fixed when viewed from the first platform; a heat transfer mechanism that transfers heat between the first fin and the second fin while maintaining a non-contact relationship; a Peltier module provided between the second fin and the second platform, one heat transfer surface of the Peltier module being in contact with the second fin and the other heat transfer surface being in contact with the second platform, and comprising: a control unit that controls the temperature of the second fin by means of the Peltier module.

Description

[Technical Field]

[0001] The present invention relates to a platform device, which includes a charged particle wire device therein. [Previous Technology]

[0002] The integration level of semiconductor products is increasing year by year, and their circuit patterns are becoming increasingly sophisticated. For semiconductor wafers with circuit patterns, various inspection methods are used for the purpose of quality management and yield improvement. As one such method, there is a known technique that uses a scanning electron microscope to photograph semiconductor wafers and inspects the circuit patterns from the obtained images.

[0003] In samples such as semiconductor wafers, circuit patterns are formed at high density, so high positional accuracy is particularly important for the platform device used in scanning electron microscopes.

[0004] As a method to improve the positional accuracy of a platform device, there is a technique that uses a floating platform to prevent vibration propagation and thus prevent positional errors caused by vibration. However, the platform device used in scanning microscopes is used in a vacuum space, so if it is designed as a floating platform, heat dissipation of the platform will be difficult to implement. If heat dissipation of the platform cannot be implemented, the platform temperature will change due to the heat generated inside the platform, which will cause thermal deformation and lead to a deterioration in positional accuracy. In view of this, Patent Document 1 discloses a technique for actively cooling a floating platform to improve positional accuracy. Patent Document 1 discloses a technique that, in order to suppress the temperature rise of the platform and prevent thermal deformation to further improve positional accuracy, creates a blackbody surface for a magnetic levitation platform in a vacuum, places a radiation plate on the blackbody surface in a non-contact state, cools the radiation plate from the back using a Peltier element, and then cools the opposite side of the Peltier element by a cooling plate, thereby suppressing thermal deformation of the platform. In addition, as another embodiment, Patent Document 1 discloses that a Peltier element is arranged on the upper side of a magnetic levitation platform, and the Peltier element is driven according to the position of the platform on the plane to achieve effective cooling.

[0005] On the other hand, radiative heat conduction (=radiative heat transfer) is generally weaker than solid heat conduction. Under the same temperature difference, the heat flux of radiative heat conduction is often smaller than that of solid heat conduction. Patent Document 2 provides a solution to this problem. In Patent Document 2, to increase the area of ​​the surface for radiative heat transfer, fins with a comb-like cross-sectional shape are arranged face-to-face, and radiative heat transfer occurs between the two fins, thereby increasing the heat transfer area per unit space. Furthermore, these fins are designed to extend in the direction of platform movement, so that the fins will not interfere with each other even if the platform moves. Moreover, Patent Document 2 discloses that a Peltier element is arranged on the side of the platform that moves relative to the fixed side. If a Peltier element is arranged on the fixed side of the moving platform, the relative positional relationship between the Peltier element and the moving platform will frequently change, but when a Peltier element is arranged on the moving platform side, the relative positional relationship is maintained. This means that no matter how the platform moves, the relative position of the Peltier element remains unchanged, thus providing a significant advantage for platform temperature control. [Previous Technical Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2003-058258 [Patent Document 2] Japanese Patent Application Publication No. 2006-351741 [Summary of the Invention]

[0007] [Problem to be Solved by the Invention] If the Peltier element is arranged on the side of the moving platform as in Patent Document 2, the heat generated by the electrical power required to operate the Peltier element must also be transferred to the stationary side via radiative heat transfer. On the other hand, when the Peltier element is arranged on the stationary side as in Patent Document 1, the heat generated by the electrical power consumed by the Peltier element does not need to be transferred via radiative heat transfer. Therefore, the method of arranging the Peltier element on the side of the moving platform has the disadvantage of increasing the radiative heat transfer load compared to arranging the Peltier element on the stationary side.

[0008] Furthermore, when the Peltier element is arranged on the fixed side as in Patent Document 1, and the comb-shaped fins are used face to face as in Patent Document 2, the problem of difficulty in properly controlling the platform temperature arises due to the time delay that occurs when the temperature of the fins changes.

[0009] In a typical device, the time from when the platform remains at one location to when it moves to the next location is not long. When a Peltier element is positioned on the fixed side, if the platform moves, the control system must respond so that the Peltier element positioned at the destination cools the platform. However, when the Peltier element cools the fins, the temperature difference between the fins facing each other increases, thereby increasing radiative heat transfer to cool the platform. The time from when the Peltier element absorbs more heat to when the temperature of the cooled fins drops is delayed due to the heat capacity of the fins. Therefore, if the Peltier element is only intended to absorb more heat and lower the fin temperature to cool the platform after it has moved, by the time the fin temperature drops to a level sufficient to cool the platform, the platform has already moved to the next location, resulting in inadequate cooling of the platform. This problem is not present when the Peltier element is positioned on the moving side, as in Patent Document 2, because the Peltier element moves with the platform. However, this configuration presents the challenge of a larger radiative heat transfer load compared to arranging Peltier elements on the fixed side.

[0010] When, as in Patent Document 1, the heat-absorbing surface of the Peltier element is used directly as the radiative heat transfer surface instead of fins, the heat absorbed from the platform changes immediately when the current of the Peltier element changes. Therefore, the aforementioned delay does not cause a problem. However, if the Peltier element is arranged on the fixed side and comb-shaped fins are used, the time delay of the temperature control system is large compared to the time interval when the platform changes location. Therefore, the unique problem of the platform's temperature control is difficult to solve.

[0011] The object of this invention is to provide a platform device that reduces the cooling load on the platform caused by radiative heat transfer, thereby improving efficiency, and to prevent thermal deformation by preventing changes in platform temperature over time, thus improving the positioning accuracy of the platform during positioning, and a charged particle wire device equipped with the present invention. [Technical Means for Solving the Problem]

[0012] To achieve the above objectives, the present invention is configured as follows.

[0013] A platform device comprising: a first platform for linear movement; a first fin extending in the direction of linear movement of the first platform and having a comb-like cross-sectional shape; a second platform having a second fin arranged opposite to the first fin and fixed when viewed from the first platform; a heat transfer mechanism for transferring heat between the first fin and the second fin while maintaining a non-contact relationship; wherein a Peltier module is provided between the second fin and the second platform, one heat transfer surface of the Peltier module being in contact with the second fin and the other heat transfer surface being in contact with the second platform, and comprising: a control unit for controlling the temperature of the second fin by means of the Peltier module, thereby controlling the heat transfer occurring between the second fin and the first fin on the first platform side. Under this premise, a plurality of Peltier modules are arranged on the second platform along the moving direction of the first platform. By controlling the plurality of Peltier modules, the temperature of the second fin is made uniform, thereby ensuring uniform heat transfer regardless of where the first platform moves. Furthermore, a charged particle wire device incorporating this platform arrangement is constructed. [Effects of the Invention]

[0014] By arranging Peltier elements on the fixed-side platform, the load of radiative heat transfer is reduced, and the heat transfer capacity is improved by increasing the surface area caused by the fins. Furthermore, the problem of temperature control delay caused by the heat capacity of the fins is solved, thereby preventing time-varying platform temperatures. This provides a platform device that can prevent thermal deformation of the platform, thereby improving the positioning accuracy of the platform during positioning, and a charged particle wire device incorporating the same.

Implementation Method

[0016] The following uses drawings to illustrate embodiments of the present invention. [Embodiment 1]

[0017] The structure and system of the platform device in Embodiment 1 of the present invention are shown in Figures 1 and 2. Figures 1 and 2 are diagrams showing the viewing platform device with its orientation changed by 90°, illustrating the same device.

[0018] In this platform device, the upper platform 1 is a floating platform, and the lower platform 2 is a rail-type platform. In Figure 1, the upper platform 1 ("floating platform," or also called "first platform") moves in the direction of passing through the paper, and its direction of movement is indicated by arrow 100. In addition, the lower platform 2 (also called "second platform") moves in the direction of arrow 101. In Figure 2, the upper platform 1 moves in the direction indicated by arrow 100, and the lower platform 2 moves in the direction of passing through the paper.

[0019] The upper platform 1 is driven by a linear motor, which is composed of a mover, i.e., a coil component 46, and a stator, i.e., a magnet component 47. Current flows through the coil component 46 in the magnetic field formed by the magnet component 47, thereby generating thrust. This thrust is transmitted to the upper platform 1, causing the upper platform 1 to move in the direction of arrow 100. Driving the platform in this way generates heat due to the current flowing through the coil component. That is, the coil necessarily has resistance, and Joule heating is generated proportional to the product of the resistance and the square of the current flowing there. Since the coil component 46 must transmit thrust to the upper platform 1, the two must be connected. The Joule heating of the coil component 46 is transmitted to the upper platform 1, causing the temperature of the upper platform 1 to rise. Furthermore, the mechanisms for levitation of the upper platform 1, the mechanisms for measuring the platform's position, and the mechanisms for driving the lower platform 2 are omitted in Figures 1 and 2.

[0020] As shown in Figure 1, heat dissipation fins 5 (also referred to as "first fins") are installed on the bottom surface of the floating platform 1. The heat dissipation fins 5 have a comb-shaped cross-section and extend in the direction of penetration into the paper of the floating platform 1. The heat absorption fins 6 (also referred to as "second fins") described later also have a comb-shaped cross-section. The two fins are designed so that the tips of the comb teeth face each other, and the comb teeth are arranged in a way that inserts into the gaps between each other. By making such an arrangement, it is possible to create a face-to-face arrangement in which most of the surface area of ​​the two fins is exposed.

[0021] Thermal radiation proportional to the fourth power of absolute temperature is generated from the surface of a solid, and when subjected to thermal radiation, it has the characteristic of absorbing or reflecting the energy of the thermal radiation. The ratio of radiant heat absorbed by a solid surface is called emissivity, which is equivalent to the proportion of thermal radiation actually occurring relative to the heat radiated from the surface of a blackbody. Therefore, ideally, the heat dissipation fins 5 and the heat absorption fins 6 should have high emissivity. In the heat dissipation fins 5, heat is released from the fin surface, thereby the temperature decreases from the root of the comb teeth towards the tip. Therefore, the material of the fins is preferably a material with high thermal conductivity. In addition, in a platform that moves repeatedly, the lighter the mass of the parts, the smaller the inertial force, which helps to reduce vibration. Therefore, the lower the density (lower the specific gravity) of the fin material, the better. Aluminum is a material with high thermal conductivity and low density, especially A6063 or A6061, which are suitable materials for fins. On the other hand, aluminum generally has low emissivity. Therefore, when forming fins from aluminum, it is preferable to apply surface treatments to increase emissivity. Furthermore, aluminum is typically treated with alumite to modify its surface and improve corrosion resistance. It is even better to apply a special alumite treatment to both the heat dissipation fins and the heat absorption fins to increase emissivity.

[0022] The heat-absorbing fins 6 are connected to the lower platform 2 via (through) the Peltier module 7. Preferably, the design prevents the heat-absorbing fins 6 from directly contacting the lower platform 2, and instead allows for more precise temperature control of the heat-absorbing fins 6 via the Peltier module 7 (also referred to as the "first Peltier module"). The Peltier module 7 typically consists of a plurality of Peltier elements arranged on an electrically insulating plate, connected by electronic circuitry. Both the upper and lower surfaces are constructed using insulating plates, with one side serving as the heat-absorbing surface and the other as the heat-dissipating surface.

[0023] In this embodiment, the upper surface of the Peltier module 7 is a heat-absorbing surface, which cools the heat-absorbing fins 6. Furthermore, the lower surface of the Peltier module 7 is a heat-dissipating surface, which, by contacting the lower platform 2, transfers the heat dissipated by the Peltier module 7 to the lower platform 2. Even when the Peltier module 7 is in operation, the law of conservation of energy necessarily holds. Therefore, the heat absorbed by the Peltier module plus the power consumed (=power supplied) becomes the heat dissipation. Thus, without heat dissipation, heat cannot be absorbed. Therefore, cooling the heat-absorbing fins 6 using the Peltier module 7 can only be achieved by dissipating heat from the lower platform 2. The lower platform 2 transfers the heat received from the Peltier module 7 to the guide rail 3 through the sliding component 8, and this heat is then transferred to the base 4 of the platform device. When this platform device is located inside a vacuum container, the base 4 is most likely a vacuum container.

[0024] In order to efficiently cool the floating platform using the heat-absorbing fins 6, it is preferable to design the heat-absorbing fins 6 to absorb only radiative heat transfer from the heat dissipation fins 5, and not accept heat transfer from other sources. As a means to achieve this, the fins at both ends of the heat-absorbing fins 6 can also be designed to be covered by the heat dissipation fins on both sides (in the case of the configuration in Figure 1, the number of fins of the heat dissipation fins 5 can be made to be one more than the number of fins of the heat-absorbing fins 6, etc.). If designed in this way, it can be prevented that the heat-absorbing fins 6 absorb heat from other sources and cause unnecessary load on the Peltier module 7.

[0025] Furthermore, the back side of the root of the teeth of the comb-shaped heat-absorbing fin 6 is face-to-face with the lower platform 2. The heat-absorbing fin 6 is preferably designed not to receive radiative heat transfer from the lower platform 2, and the back side of the heat-absorbing fin 6 can reduce emissivity.

[0026] When the heat-absorbing fin 6 is made of aluminum, only the front side of the fin can be surface-treated to increase emissivity, while the back side is left exposed to expose the aluminum substrate, thus creating a high reflectivity. In addition, in the structure in which the heat-absorbing fin 6 and the Peltier module 7 are fixed together to the lower platform 2, a structure that suppresses heat conduction can also be made.

[0027] With the Peltier module 7 in between, the heat-absorbing fins 6 are installed by pushing against the lower platform 2 with bolts. This applies pushing pressure to the heat transfer surface, which is preferable. However, if the bolts have high thermal conductivity, heat will flow from the lower platform 2 to the low-temperature heat-absorbing fins 6, and the cooling load on the Peltier module will increase accordingly. Therefore, the bolts used to install the heat-absorbing fins 6 to the lower platform with the Peltier module 7 in between can be made of a material with low thermal conductivity, such as resin.

[0028] To maintain the temperature of the floating platform 1 at the target temperature, a temperature measuring unit (not shown) can be used to measure the temperature while simultaneously sending a command to the power supply component 10 that supplies current to the Peltier module 7, thereby implementing feedback control of the cooling capacity of the Peltier module 7. Assuming the measured temperature of the floating platform 1 is recorded as Ts and the target temperature as Ts', when Ts > Ts', the current flowing through the Peltier module 7 is increased, increasing the cooling capacity. Conversely, when Ts < Ts', the current flowing through the Peltier module 7 is decreased, reducing the cooling capacity. Furthermore, to improve this control action, PID control can be implemented. That is, using the value of Ts-Ts', the time derivative of that value, and the time integral of that value—three variables—and by setting proportional coefficients (=weighting) for each of the three variables and summing the results, the method of determining the current flowing through the Peltier module 7 is determined.

[0029] In addition, a control method can also be used that takes into account the time delay from the change in current flowing through the Peltier module 7 to the temperature change of the heat-absorbing fins 6, and then to the temperature change of the heat dissipation fins 5 and the floating platform body 1. These control calculations are performed by the controller 11 ("control unit", or "controller").

[0030] As shown in Figure 2, if viewed from the side in the direction of the floating platform 1's movement, in this embodiment, three Peltier modules 7 are arranged along the moving direction of the floating platform 1. This arrangement of three is merely an example; the number can be changed as necessary. To allow the floating platform 1 to move in all directions, a movement range larger than the size of the main body 1 is set. To ensure cooling capability at any point within this movement range, multiple Peltier modules can be arranged along the platform's moving direction.

[0031] In this embodiment, when using a plurality of Peltier modules, the electronic circuits used to supply current are configured as parallel circuits, and the same voltage (V) is applied to all Peltier modules. The purpose of applying the same voltage is to uniformize the temperature of the heat-absorbing fins 6 relative to the direction of movement of the floating platform 1. Although the heat-absorbing fins 6 are illustrated in FIG2 with a shape divided according to each Peltier module, the heat-absorbing fins 6 can also be manufactured as a single unit.

[0032] If manufactured as a single unit, it has the advantage of uniform temperature throughout through heat conduction by the solid. On the other hand, when the temperature of the heat-absorbing fins is significantly reduced, the temperature difference compared to other parts becomes larger, and the heat-absorbing fins alone will experience significant thermal contraction, resulting in thermal stress. When the heat-absorbing fins 6 are divided into individual Peltier modules, this thermal stress is reduced.

[0033] As shown in Figure 2, when the floating platform 1 is tilted to the left side of its movement range and remains stationary for a long time, it mainly exchanges heat with the heat-absorbing fins 6 on the left side. That is, the heat generated by the floating platform 1 is transferred to the heat-absorbing fins 6 through the heat dissipation fins 5. However, at this time, radiative heat transfer mainly occurs at the point where the surfaces of the fins face each other. Therefore, the heat-absorbing fins 6 are only subjected to heat load at the location of the heat dissipation fins 5. Nevertheless, if the temperature of the floating platform 1 is measured and the cooling capacity of the Peltier module is controlled by feedback, the floating platform 1 can be made to reach the target temperature. However, this is the situation when the floating platform 1 stays in the same place. If the floating platform 1 is imagined to move around, the situation will be different.

[0034] When the floating platform 1 is tilted to the left side of its movement range and remains stationary for an extended period, and multiple Peltier modules are operating with the same cooling capacity, while the floating platform 1 maintains its target temperature, the heat-absorbing fins 6 in areas without the floating platform will not be subjected to heat load and will become overcooled. That is, the heat-absorbing fins 6 on the right side of Figure 2 will become cooler than those on the right side. However, this is not a problem if the floating platform 1 does not move to the right side, but if it suddenly moves to the right side, it will cause the floating platform to be overcooled. If the overcooling state of the floating platform 1 is detected, the cooling capacity of the Peltier modules can be reduced, but this will cause a time delay, and it is impossible to prevent the temperature of the floating platform from dropping temporarily. In contrast, if current is supplied to multiple Peltier modules in parallel circuit as shown in Figure 2, this can be prevented.

[0035] Using the formulas representing the motion characteristics of the Parthenon module, the principle behind achieving the above-mentioned feats is explained. The variables used in the formulas are shown in Table 1.

[0036]

[0037] First, Equation (1) illustrates the heat absorption [W] of the Peltier module.

[0038]

[0039] The heat absorption of the Peltier module is proportional to the current flowing through it, and its proportionality can be expressed by the Seebeck coefficient and the absolute temperature of the heat-absorbing surface. On the other hand, the temperature difference between the heat dissipation surface and the heat absorption surface of the Peltier module, expressed by equation (3), will induce heat conduction, thereby reducing the heat absorption of the Peltier module.

[0040]

[0041] Furthermore, the resistance of the Peltier module will generate Joule heat according to the current flowing there, and this heat will flow to half of the heat-absorbing surface and half of the heat-dissipating surface. On the other hand, the first term on the right side of the equation (2) concerning the heat dissipation of the Peltier module indicates the effect caused by the current, and its proportionality coefficient is composed of the Seebeck coefficient and the absolute temperature of the heat dissipating surface.

[0042]

[0043] The difference in the coefficients of heat absorption and heat dissipation with respect to current is due to the Seebeck effect. This Seebeck effect can be described by equation (4), which is the phenomenon of generating thermoelectric potential that is proportional to the temperature difference between the heat dissipation surface and the heat absorption surface.

[0044]

[0045] Because of this Seebeck effect, the voltage applied to the two ends of the Peltier module is described as in equation (5).

[0046]

[0047] That is, the sum of the voltage generated by current × resistance and the thermoelectric potential caused by the Seebeck effect will become the voltage when current flows through the Peltier module. Incidentally, the power supplied to the Peltier module (= power consumed) is the same as the load of ordinary DC current, and can be calculated by voltage × current. In addition, the difference between heat dissipation and heat absorption will become the law of conservation of energy for power consumption, which holds true in the formula of this system. If we take the difference between equation (2) and (1), we can confirm the relationship of equation (6).

[0048]

[0049] As explained in the formula of this system, in a Peltier module, a thermoelectric electromotive force (i.e., voltage) is generated proportional to the temperature difference between the heat dissipation surface and the heat absorption surface. In the configuration shown in Figure 2, the floating platform 1 is biased to the left, so the heat absorption fins on the right side are not subjected to heat load, and the heat absorption fins are prone to overcooling, as has been explained. In this case, it means that the temperature of the heat absorption surface of the right Peltier module is lower than that of other Peltier modules. In this case, it means that the temperature difference between the heat dissipation surface and the heat absorption surface of the right Peltier module will become larger. As a result, the thermoelectric electromotive force caused by the Seebeck effect will become larger than that of other Peltier modules.

[0050] When the same voltage is applied to all Peltier modules, if the thermoelectric potential of one Peltier module increases, the voltage caused by the current multiplied by the resistance will decrease accordingly. This decrease in voltage means that the current flowing through the Peltier module decreases. As a result, when the same voltage is applied to a plurality of Peltier modules, if there is a Peltier module whose heat-absorbing surface temperature decreases and its thermoelectric potential increases, the current flowing through that Peltier module will be lower than the others. As a result, the cooling effect of the Peltier module will decrease, and therefore the temperature of the heat-absorbing surface of the Peltier module will rise. Therefore, applying the same voltage to a plurality of Peltier modules will cause the heat-absorbing surface temperature to act in a uniform direction, which means that the temperature of the heat-absorbing fins will act in a uniform direction. Therefore, if current is supplied to a plurality of Peltier modules arranged in parallel circuits along the direction of movement of the floating platform 1, the temperature of the heat-absorbing fins can be homogenized relative to the direction of movement of the floating platform 1.

[0051] If the heat-absorbing fins achieve a uniform temperature along the direction of movement of the floating platform 1, the same cooling capacity can be obtained regardless of the location of the floating platform 1. Therefore, even if the floating platform 1 is continuously moved from an eccentric location to another location, its temperature can still be maintained at a constant level. Furthermore, by utilizing the control principle illustrated in Figure 1, even if the average heat generation of the floating platform 1 changes, its temperature can still be maintained at a constant level through feedback control. [Example 2]

[0052] Figure 3 illustrates the configuration and system of the platform device in the second embodiment of the present invention. Furthermore, in the following description, items with the same function will be labeled with the same symbols, thereby omitting descriptions.

[0053] The embodiment in Figure 3 differs from the first embodiment in that, instead of applying the same voltage to a plurality of Peltier modules 7 with a single power supply component, individual power supply components 12 to 14 are provided for each Peltier module. If the power supply components exist in a one-to-one relationship with the Peltier modules, the thermoelectric potential generated by each Peltier component can be determined. That is, when the power supply component 12 supplies power with current I1 and voltage V1, the thermoelectric potential Vz1 of the Peltier module can be calculated by using equation (5). The same applies to power supply components 13 and 14.

[0054] On the other hand, when controlling the temperature of the floating platform 1, the controller 18 observes the difference between the measured temperature Ts and the target temperature Ts', and determines the target thermoelectric potential Vz. This target thermoelectric potential is assigned the same target value to all Peltier modules. Under this premise, each power supply component 12-14 operates current to make the thermoelectric potential in the operating state the target value. If such current operation is performed, the thermoelectric potential of all Peltier modules becomes the same, and temperature uniformity can be achieved with higher precision than in Embodiment 1. As a result, the temperature change of the floating platform 1 will be smaller, the thermal deformation will be further reduced, thereby improving the positional accuracy. [Embodiment 3]

[0055] Figure 4 illustrates the configuration and system of the platform device in the third embodiment of the present invention. In this embodiment, the temperature of the heat-absorbing fins under the responsibility of 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, there are controllers 19 to 21 that determine the current of each Peltier module. Furthermore, when controlling the temperature of the floating platform 1, controller 22 determines the target temperature of the heat-absorbing fins. Using the target fin temperature determined by controller 22, individual controllers 19 to 21 are operated. PID control is also an effective means of using controllers 19 to 21. For each power supply component 15 to 17 of the Peltier module, the output current is determined by controllers 19 to 21 respectively, thus simplifying the internal configuration. [Example 4]

[0056] Figure 5 illustrates the configuration and system of the platform device in the fourth embodiment of the present invention. In this embodiment, a cooling system for the lower platform is added, compared to the first embodiment. The cooling system for the floating platform 1 is the same as in the first embodiment, so its description is omitted here. Alternatively, the cooling structure of the lower platform shown here can be combined with the cooling system of the floating system in the second and third embodiments.

[0057] To support the cooling of the lower platform, in this embodiment, a heat dissipation fin 23 (also referred to as the "third fin") is installed on the bottom surface of the lower platform 2. This heat dissipation fin 23 has a comb-shaped cross-section and extends in the direction of movement of the lower platform 2. In addition, a heat-absorbing fin 24 (also referred to as the "fourth fin") is provided at a position facing the heat dissipation fin 23 and is installed to the base 4 through a Peltier module 25 (also referred to as the "second Peltier module"). As in the first embodiment, when this platform device operates in a vacuum environment, the base 4 refers to a vacuum container. Furthermore, a plurality of Peltier modules 25 are arranged along the direction of movement of the lower platform 2 and are powered by a parallel circuit.

[0058] When the Peltier module 25 for cooling the lower platform is in operation, the controller 26 can control the temperature measured by the temperature measuring unit (not shown) provided on the lower platform 2, so as to make it the target temperature for the lower platform and provide feedback, and control the voltage used to supply current to the Peltier module 25.

[0059] If the temperature of the lower platform 2 is actively controlled as in this embodiment, the temperature of the lower platform 2 will be more stable. Without active temperature control, when the heat dissipation from the Peltier module 7 used for the floating platform 1 increases, the temperature of the lower platform 2 rises, and the heat transferred from the sliding component 8 to the guide rail 3 increases, causing the temperature to balance. On the other hand, if active temperature control is introduced for the lower platform 2, the temperature of the lower platform 2 does not need to change even if the heat dissipation from the Peltier module 7 changes. In this way, the temperature of the heat dissipation surface of the Peltier module 7 becomes stable, and when the current flowing through the Peltier module increases, the heat absorption simply increases. If the temperature of the heat dissipation surface of the Peltier module is unstable, the heat absorption of the Peltier module will change due to the flowing current, and will also be affected by the temperature fluctuation of the heat dissipation surface, resulting in poor control over heat absorption. Therefore, if the temperature of the lower platform 2 is actively controlled to achieve temperature stabilization, the controllability of the Peltier module 7 used for cooling the floating platform will improve, contributing more to the temperature stabilization of the floating platform 1. Furthermore, the cooling control of the lower platform 2 consistently maintains it at the predetermined target temperature, thus eliminating the need to consider the operating conditions of the floating platform 1. Therefore, it can be designed as an independent control system, preventing interference between the two control systems and resulting temperature fluctuations. [Example 5]

[0060] Figure 6 illustrates the configuration and system of the platform device in the fifth embodiment of the present invention. This embodiment also describes an additional cooling system for the lower platform 2, so the cooling system of the floating platform combined with it can be any of the first to third embodiments.

[0061] To support the cooling of the lower platform, in this embodiment, a Peltier module 27 (equivalent to "second Peltier module") is first installed on the bottom surface of the lower platform 2, and then a heat dissipation fin 28 (equivalent to the aforementioned "third fin") is installed on its heat dissipation surface. Furthermore, a heat-absorbing fin 29 (equivalent to the aforementioned "fourth fin") is installed facing the heat dissipation fin 28, and a base 4 is installed on its back side. In this embodiment, the Peltier module 27 used to cool the lower platform 2 is installed on the moving side, so it is not necessary to configure the Peltier module in a way that covers the entire moving range of the lower platform. The Peltier module 27 has its heat-absorbing surface installed on the lower platform body 2, absorbs heat from the lower platform 2, and transfers the heat to the heat dissipation fin 28. Therefore, the temperature of the heat dissipation fin 28 is higher than that of the lower platform 2. On the other hand, the heat-absorbing fin 29 is installed on the base 4, so it reaches almost the same temperature as the base 4. Previous cooling systems cooled the heat-absorbing fins to a low temperature to induce radiative heat transfer. However, in this embodiment, the cooling of the lower platform is achieved by cooling the heat dissipation fins to a high temperature, thereby inducing radiative heat transfer. In this method, the Peltier module 27 is mounted on the lower platform 2, so even if the lower platform moves, its positional relationship with the Peltier module remains unchanged, thus preventing changes in heat load. Therefore, even if multiple Peltier modules are used, they do not need to be connected in parallel; a series connection is also acceptable. If power is supplied via a series circuit, the voltage supplied from the power source increases, but the current only needs to be smaller. Generally, for power supply devices, a smaller current allows for smaller device size, thus the ability to operate with a small current has its advantages.

[0062] Furthermore, in this embodiment, to prevent radiant heat from the heat dissipation fins 28 from returning to the lower platform 2, the heat-absorbing fins 29 are designed to cover both ends of the heat dissipation fins 28. In the configuration shown in FIG6, the number of fins on the heat dissipation fins 28 is designed to be one more than the number of fins on the heat-absorbing fins 29. By constructing it in this way, heat backflow can be prevented. In addition, the surfaces of the heat dissipation fins 28 and the heat-absorbing fins 29 are preferably treated with a surface treatment to increase emissivity, but only the back surface of the heat dissipation fins 28 is preferably treated with a surface treatment to reduce emissivity. [Embodiment 6]

[0063] Figure 7 illustrates the configuration and system of the platform device in the sixth embodiment of the present invention. In this embodiment, cooling of the lower platform is supported passively rather than actively controlled. Heat dissipation fins 31 are installed on the bottom surface of the lower platform 2, and heat-absorbing fins 32 are installed facing each other, while the back surface is cooled by a heat sink 33. Refrigerant flows inside the heat sink 33, and the refrigerant is maintained at a constant temperature at the inlet of the heat sink and used at a constant flow rate. Therefore, the cooling capacity of the heat sink 33 is not actively controlled; its heat transfer varies only with the time-varying temperature of the heat dissipation fins 31. The lower platform 2 bears the combined heat load of the floating platform 1, the power consumption of the Peltier module 7, and the heat generated by the lower platform 2. Compared to simply allowing heat to escape through heat transfer from the sliding component 8 to the guide rail 3, adding a path for heat to escape to the heat sink 33 helps reduce the temperature rise of the lower platform 2, which also contributes to the temperature stabilization of the floating platform 1.

[0064] Furthermore, the cooling support provided by the heat sink 33 can also be used in combination with embodiments 4 and 5. [Embodiment 7]

[0065] Figure 8 illustrates the configuration and system of the platform device in the seventh embodiment of the present invention. The difference between this embodiment and the first embodiment is that the lengths of the heat-absorbing fins 6 cooled by each Peltier module 7 are different. In the case of a device where the ratio of the area where the floating platform 1 stays is almost fixed, the configuration density of the Peltier modules arranged in the area with a high staying ratio is increased, thereby making the heat load of the Peltier modules uniform. In the case of the embodiment in Figure 8, it is assumed that the floating platform 1 stays in the central part of its movement range at a higher ratio. In this assumed case, the heat load borne by the central Peltier module will be higher. Therefore, the length of the heat-absorbing fins 6' cooled by the central Peltier module is shortened, and instead the length of the heat-absorbing fins 6 on the left and right is lengthened. When the movement pattern of the floating platform is fixed and the staying ratio is known in advance, the heat load borne by the Peltier modules is made uniform according to the hardware design, thereby making the heat load uniform and also achieving uniform temperature of the heat-absorbing fins. With this configuration, the same cooling capacity can be obtained regardless of the location of the floating platform 1. Furthermore, although multiple Peltier modules are connected in parallel in Figure 8, current can also be supplied in series. [Simplified Explanation of the Diagram]

[0015] [Figure 1] A view of the platform device of Embodiment 1 viewed from the direction opposite to the movement of the floating platform. [Figure 2] A view of the platform device of Embodiment 1 viewed from the side from the direction of the movement of the floating platform. [Figure 3] A platform device and system diagram of Embodiment 2. [Figure 4] A platform device and system diagram of Embodiment 3. [Figure 5] A platform device and system diagram of Embodiment 4. [Figure 6] A platform device and system diagram of Embodiment 5. [Figure 7] A platform device and system diagram of Embodiment 6. [Figure 8] A platform device and system diagram of Embodiment 7.

Claims

1. A platform device, characterized in that it comprises: a first platform for linear movement; a first fin extending in the direction of the linear movement of the first platform and having a comb-like cross-sectional shape; a second platform having a comb-like cross-sectional shape and having a second fin arranged facing the first fin in such a way that the comb teeth of the second fin are inserted into the gaps between the first fin and the second fin, and being fixed when viewed from the first platform; heat transfer occurs between the first fin and the second fin while maintaining a non-contact relationship, the platform device further comprising a first Peltier module between the second fin and the second platform, one heat transfer surface of the first Peltier module being in contact with the second fin and the other heat transfer surface being in contact with the second platform, and comprising: a control unit that controls the temperature of the second fin by means of the first Peltier module, thereby controlling the heat transfer occurring between the first fin and the first fin on the first platform side.

2. The platform device as described in claim 1, wherein, The second platform has a plurality of first Peltier modules, and the plurality of first Peltier modules are arranged in a linear motion direction along the first platform. The control unit adjusts the current flowing through each of the plurality of first Peltier modules so that the temperature of the second fin provided on the second platform is approximately uniform with respect to the linear motion direction of the first platform.

3. The platform device as described in claim 2, wherein, The aforementioned control unit utilizes the thermoelectric potential generated by the temperature difference between the heat-absorbing and heat-dissipating surfaces of each of the plurality of the aforementioned first Peltier modules to control the temperature of the aforementioned second fins of the aforementioned second platform to be approximately uniform.

4. The platform device as described in claim 3, wherein, The aforementioned control unit has a parallel circuit for supplying current to a plurality of the aforementioned first Peltier modules, and controls each of the plurality of the first Peltier modules to be driven with approximately the same voltage.

5. The platform device as described in claim 2, wherein, It includes: a temperature measuring unit that measures the temperature of the first platform; and a control unit that controls the current flowing through a plurality of the first Peltier modules to control the temperature change of the second fin of the second platform, so that the temperature of the first platform measured by the temperature measuring unit becomes a preset target temperature.

6. The platform device as described in claim 1, wherein, The aforementioned second platform is a lower platform that can move along with the aforementioned first platform. The movement directions of the aforementioned first platform and the aforementioned second platform are slightly orthogonal, thereby enabling the first platform to move in two dimensions.

7. The platform device as described in claim 6, wherein, The bottom surface of the aforementioned second platform has a third fin with a comb-like cross-sectional shape. The fixing part that fixes the aforementioned second platform has a fourth fin facing the aforementioned third fin. Through the heat transfer between the third fin and the fourth fin, the heat of the aforementioned second platform is transferred to the aforementioned fixing part.

8. The platform device as described in claim 7, wherein, It includes: a second Peltier module for promoting heat transfer across the aforementioned second platform and the aforementioned fixed part; and a control unit for controlling the aforementioned second Peltier module so that the temperature of the aforementioned second platform becomes a preset target temperature.

9. The platform device as described in claim 8, wherein, The first platform is used in a floating state relative to the second platform, and the second platform moves while contacting the guide rail provided on the fixed part.

10. The platform device as described in claim 9, wherein, The first platform moves linearly using a linear motor, which is a moving-coil linear motor.

11. A charged particle beam apparatus, characterized in that it comprises: a charged particle beam irradiation section, and a platform device as described in any one of claims 1 to 10 provided in a frame maintained in a vacuum, the platform device being used for positioning a sample and irradiating the sample with charged particle beams.

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