Holding device, lithographic apparatus, and article manufacturing method

Abstract

To provide a technique capable of controlling the shape of a substrate with high precision and stability.SOLUTION: A holding device includes a holding unit that holds an object, a phase change material that is arranged inside the holding unit or on a holding surface of the object and changes in phase between an amorphous phase and a crystalline phase to change in volume in accordance with the change in phase, and a control unit that controls heating of the phase change material using a heating unit for heating the phase change material so as to deform the holding surface by causing a volume change in the phase change material.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a holding device, a lithographic apparatus, and an article manufacturing method. [Background technology]

[0002] In the semiconductor manufacturing process, undesirable unevenness or distortion on the surface of a semiconductor substrate (hereinafter simply referred to as "substrate") affects the processing accuracy. Therefore, it has been proposed to provide a mechanism for deforming the substrate in the substrate holding mechanism that holds the substrate, thereby correcting the unevenness or distortion of the substrate.

[0003] Patent Document 1 describes a method in which a plurality of height control elements capable of changing the height are arranged on a stage on which a substrate is mounted, and the height control elements are driven to control the unevenness of the substrate. For example, a piezoelectric element is used as the height control element used for position control on the order of nanometers.

[0004] However, it can be difficult to control the position of a piezoelectric actuator even for a short period of time. Generally, piezoelectric actuators have hysteresis drive characteristics and creep change characteristics in displacement. Therefore, to achieve highly accurate and stable drive, it is necessary to provide a separate sensor to measure the piezoelectric displacement and perform position control in a closed servo loop. Generally, it is difficult to control the position of a piezoelectric actuator in an open loop.

[0005] To address these issues with piezoelectric actuators, Patent Document 2 proposes the application of electrostatic actuators, which can stably maintain a position due to less leakage of electric charge. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-026233 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-135218 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the miniaturization of semiconductor devices and the like has made the precision required for substrate deformation more stringent, and high stability and precision are required for the actuators that deform the substrate. Even with the electrostatic actuator described in Patent Document 2, charge leakage cannot be reduced to zero, so a substrate deformation mechanism that utilizes a highly stable actuator is required.

[0008] The present invention provides a technique that enables the shape of a substrate to be controlled with high precision and stability. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a holding device comprising: a holding section for holding an object; a phase change material that is disposed inside the holding section or on the holding surface of the object and that changes phase between an amorphous phase and a crystalline phase and changes volume in accordance with the phase change; and a control section that controls heating of the phase change material using a heating section that heats the phase change material so as to cause a volume change in the phase change material and thereby deform the holding surface. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a technique that allows for highly accurate and stable control of the shape of a substrate. [Brief explanation of the drawings]

[0011] [Figure 1] 3A to 3C are diagrams illustrating the configuration of a holding device and a substrate deformation process in the first embodiment. [Figure 2] 10A to 10C are diagrams illustrating the configuration of a holding device and a substrate deformation process in the second embodiment. [Figure 3] 10A to 10C are diagrams illustrating the configuration of a holding device and a substrate deformation process in the third embodiment. [Figure 4]FIG. 10 is a diagram showing the configuration of a substrate processing system according to a third embodiment. [Figure 5] 5A to 5C are diagrams illustrating a method for measuring displacement of a substrate. [Figure 6] 10A to 10C are diagrams illustrating the configuration of a holding device and a substrate deformation process in the fourth embodiment. [Figure 7] FIG. 10 is a diagram illustrating the arrangement of a phase-change material in Example 4. [Figure 8] FIG. 10 is a diagram illustrating the arrangement of a phase-change material in Example 5. [Figure 9] 1 is a diagram showing the characteristics of a phase change material; [Figure 10] 10 is a flowchart showing a substrate deformation process. [Figure 11] 13A to 13C are diagrams illustrating a method for inclining the upper surface of the protrusion in the sixth embodiment. [Figure 12] 13A to 13C are views for explaining another method for inclining the upper surface of the protrusion in the sixth embodiment. [Figure 13] FIG. 13 is a diagram showing a configuration for increasing the amount of upward deformation of a phase-change material in Example 7. [Figure 14] FIG. 1 is a diagram showing the configuration of an exposure apparatus that uses a holding device. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0013] First Embodiment FIG. 1(A1) shows an example of the configuration of a holding device 100 according to the first embodiment, which holds a plate, which is an object to be held. In one example, the plate is a semiconductor wafer used in a lithography apparatus, in which case the holding device 100 is a substrate holding device. Alternatively, the plate is an original (mask or reticle) on which a pattern is drawn, which is used in an exposure apparatus, which is a type of lithography apparatus, in which case the holding device 100 is an original holding device. Alternatively, the plate is a mold on which a pattern is formed, which is used in an imprint apparatus, which is a type of lithography apparatus, in which case the holding device 100 is a mold holding device. In the following description, as an example, the plate is a substrate 105 (semiconductor wafer) used in a substrate processing apparatus such as a lithography apparatus.

[0014] The holding device 100 includes a substrate holding unit 101 that suction-holds a substrate 105, which is a plate. The method of suctioning the substrate 105 by the substrate holding unit 101 can be a vacuum method in which the substrate 105 is held by generating a negative pressure between the substrate 105 and a substrate holding surface (holding surface) of the substrate holding unit 101. Alternatively, the method of suctioning the substrate 105 by the substrate holding unit 101 can be an electrostatic suction method in which the substrate 105 is held by using an electrostatic suction force.

[0015] The holding device 100 further includes a phase change material 102 and a control unit C that controls heat input to the phase change material 102. The control unit C controls heating of the phase change material 102 using a heating unit that heats the phase change material 102 so as to cause a volume change in the phase change material 102 and thereby deform the holding surface. In this embodiment, a heating unit 103 is disposed inside the substrate holding unit 101. Although the phase change material 102 is disposed inside the substrate holding unit 101 in FIG. 1(A1), it may also be disposed on the holding surface of the substrate (the upper surface of the substrate holding unit 101).

[0016] In this embodiment, the heating unit 103 includes multiple heating units. Each heating unit 103 may include a heater element made of a resistive heat-generating material for heating the phase change material 102. Examples of the resistive heat-generating material include a mixture of one or more of copper, nickel alloy, and chromium alloy. The heater element generates heat using power supplied from a power source (not shown). Alternatively, each heating unit 103 may include an induction heating element that generates heat using electromagnetic induction generated by a coil disposed around a ferromagnetic material. While the multiple heating units 103 are arranged below the phase change material 102 in FIG. 1A1, they may also be arranged inside the phase change material 102 or between the phase change material 102 and the substrate holding surface of the substrate holding unit 101. Variations in the arrangement of the phase change material 102 and the multiple heating units 103 will be described later.

[0017] The phase-change material 102 will be described with reference to FIG. 9. The phase-change material 102 is a material that undergoes a phase change between a non-crystalline phase (amorphous phase) and a crystalline phase, and its volume changes as the phase change occurs. FIG. 9 is a diagram showing the transition of the crystalline structure and the volume characteristics of the phase-change material with temperature. When a phase-change material is heated from room temperature RT to its melting point Tm and then rapidly cooled, it becomes a supercooled liquid and assumes an amorphous structure with a large volume at room temperature. On the other hand, when a phase-change material is heated from room temperature RT to a temperature exceeding its glass transition temperature Tg and then slowly cooled, it assumes a crystalline structure with a small volume at room temperature. In other words, the structure at room temperature can be changed by changing the heating and cooling method. As shown in FIG. 9, a crystalline structure in which elements are aligned tends to have a small volume, while an amorphous structure in which elements are random tends to have a large volume.

[0018] Phase-change materials have been put to practical use in the field of rewritable recording media. For example, chalcogenide-based phase-change material Ge—Sb—Te (hereinafter, GST) is widely used as a recording material for the recording layers of rewritable optical discs such as DVDs and Blu-ray (registered trademark) discs, and for nonvolatile memories. GST exhibits a volume change of approximately 5% between its amorphous and crystalline states. Taking advantage of this characteristic, control unit C controls multiple heating units 103 to deform the holding surface of holding unit 101 by causing a volume change in phase-change material 102.

[0019] Example 1 Below, we will explain a specific example of a method for deforming a substrate in the holding device 100. First, Example 1 according to the first embodiment will be explained with reference to Figures 1(A1) to 1(A3) and 10.

[0020] In step S0, the control unit C determines whether the target shape can be achieved by the current amount of shape correction due to volumetric shrinkage caused by crystallization of the phase change material 102, i.e., whether the correction by crystallization is sufficient. If it is determined that the correction by crystallization is insufficient, the process proceeds to the amorphization process in step S1. If it is determined that the correction by crystallization is sufficient, the process skips step S1 and proceeds to shape measurement in S2.

[0021] In step S1, the control unit C drives (supplies power to) all of the heating units 103 to heat the phase change material 102 to a temperature above the melting point Tm, and then quickly cools it by momentarily cutting off the heating. Rapid cooling may be performed by instantly cutting off the power supply to the heating units 103, or may be performed by forced cooling using heat exchange with a refrigerant. Rapid cooling causes the phase change material 102 to become amorphous and reach its largest volume (first step). In this case, since the phase change material 102 is heated above its melting point, it is desirable to minimize the external force applied to it. Therefore, it is advisable to temporarily move the substrate 105 away from the substrate holder 101 during heating.

[0022] In step S2, the control unit C measures the shape of the measurement target using a measurement unit (described later). The shape of interest here is the unevenness of the substrate surface, i.e., the amount of deformation of the substrate surface in the out-of-plane direction. Therefore, the measurement result includes information on the amount of deformation of the substrate surface in the out-of-plane direction. The measurement target may be the surface of the substrate 105 held by the substrate holding unit 101, as shown in FIGS. 5(a) and 5(b). Alternatively, if the substrate 105 is retracted, the measurement target may be the surface of the substrate 105 (substrate holding surface) of the substrate holding unit 101. However, considering distortion caused by the substrate holding unit 101 holding the substrate 105 and unevenness measurement errors, using the substrate 105 held by the substrate holding unit 101 as the measurement target can reduce error factors. In the following description of Example 1, the surface of the substrate 105 held by the substrate holding unit 101 is described as the measurement target. Furthermore, a measurement substrate may be used instead of the substrate 105.

[0023] As a measurement method, either a method using a displacement measurement unit 106 that measures local displacement, as shown in FIG. 5(a), or a method using a planar displacement meter side unit 1061 that simultaneously measures unevenness over a wide area, as shown in FIG. 5(b), may be employed. Sensors used in FIG. 5(a) include a distance measuring interferometer, a triangular displacement meter, and the like. The height of any position on the substrate holder 101 or the substrate 105 is measured by driving (relatively driving) either or both of the displacement measurement unit 106 and the substrate holder 101 in the left-right and depth directions of the page. In the simultaneous measurement method shown in FIG. 5(b), for example, a planar interferometer is used as the planar displacement meter side unit 1061. However, because a planar interferometer with a measurement range that can measure the entire surface of the substrate 105 is expensive, a planar displacement meter side unit with a measurement range narrower than the substrate 105, as shown in FIG. 5(b), may be used. In this case, the entire surface of the substrate 105 can be measured by driving the planar displacement measuring unit 1061 and the substrate holding unit 101 relative to each other in the same manner as in FIG. 5(a).

[0024] 5(a), in which the displacement measurement unit 106 and the substrate holder 101 are driven relatively, the method is generally affected by running errors of the stages of the displacement measurement unit 106 and / or the substrate holder 101. Therefore, in order to improve measurement accuracy, measurement using a planar displacement gauge that measures a wide range all at once can reduce measurement errors.

[0025] The size of the collective measurement range of the planar displacement meter side portion 1061 is preferably large enough to encompass the shot area, which is the largest constituent unit of a device manufactured on the substrate 105. In this case, the shot area can be measured in a single operation, and errors due to relative driving can be reduced. Furthermore, by making the size of the collective measurement range slightly larger than the shot area, it is possible to extend the measurement to the entire surface of the substrate 105 by stitching, which aligns the overlap of displacement measurements with adjacent shot areas.

[0026] In step S3, as shown in FIG. 1A2, the control unit C determines a portion of the heating units 103 (one or more specific heating units) to be heated based on the measurement results of the shape of the substrate holding surface or the surface of the substrate 105 measured in step S2. The control unit C supplies power to the determined portion of the heating units 103 according to the position and amount of lowering of the substrate holding unit 101. This partially heats the phase change material 102. Specifically, in the area of ​​the substrate surface where a large depression is desired, the temperature of the specific heating unit is increased or the heat input is increased so that a wide range of the phase change material 102 exceeds the glass transition temperature Tg. Subsequently, the phase change material 102 in the range above the glass transition temperature Tg is gradually cooled, causing the phase change material 102 to change to crystal and shrink in volume (step 2). The slow cooling can be performed, for example, by gradually reducing the amount of power supplied (heat input) to the heating unit. As a result, the substrate holding surface of the substrate holding unit 101 can be depressed as shown in FIG. 1A3. By changing the range of contraction caused by phase change to crystal depending on the heating state of the heating part, it is possible to control the unevenness of the substrate holding surface.

[0027] As an example, a case will be described in which a phase change material that undergoes a 10% volume change during a phase change is used as the phase change material 102. In FIG. 1(A2), the temperature of the rightmost heating element 103 is raised so that the entire phase change material 102 exceeds the glass transition temperature Tg, and then gradually cooled, causing a 10% volume contraction of the phase change material 102. As an example, if the thickness of the phase change material 102 is 10 μm, a 10% volume change will result in a 0.01 μm contraction in the thickness direction.

[0028] Although GST is used as an example of the phase change material 102, Ge-Te, Ge-Sb-Te, Ge-In-Sb-Te, and Ag-In-Sb-Te based materials can also be used. All of these materials exhibit a volume change of several percent due to a phase change, and the optimal phase change material can be designed and selected based on the relationship between the substrate holder 101, the multiple heating units 103, etc.

[0029] In step S4, the controller C measures the shape of the substrate 105, which is the measurement target, as in step S2. Next, in step S5, the controller C determines whether the difference between the shape of the substrate 105 and the target shape is within the tolerance. If the difference is not within the tolerance, the process returns to step S3, where the controller C again performs heating and cooling to correct the shape. However, as the corrections from step S5 to step S3 are repeated, the phase change material 102 will all crystallize, making it impossible to further reduce its volume. Therefore, in step S6, the controller C determines whether the deformation of the phase change material 102 is within a range that can be corrected. If the deformation of the phase change material 102 is not correctable, the process returns to step S1, where the controller C resets the phase change material 102, i.e., amorphizes the phase change material 102 by heating it above its melting point and then rapidly cooling it again.

[0030] The above describes a method for controlling the unevenness (i.e., the shape in the out-of-plane direction) of the substrate 105. Below, with reference to Figures 1(B1) to (B3), a case will be described in which the shape in the in-plane direction of the substrate 105 is controlled in the deformation of the substrate 105 of Example 1. In this case as well, the flowchart of Figure 10 can be applied in the same way as above.

[0031] Deformation in the in-plane direction is generally called strain. The substrate 105 shown in Figure 1(B1) is expressed as a vertical lattice pattern to conveniently explain the state of strain, and in Figures 1(B2) and (B3), the distribution of strain after deformation is expressed by the density of the vertical lattice.

[0032] As in the case of the substrate unevenness deformation described above, in step S1, the control unit C drives all of the multiple heating units 103 to heat the phase change material 102 to a temperature above the melting point Tm, and then quickly cools it by momentarily turning off the heating. Rapid cooling causes the phase change material 102 to become amorphous, resulting in the largest volume. In this case, since the phase change material 102 is heated above its melting point, it is desirable to minimize the external force applied to it. Therefore, it is advisable to temporarily move the substrate 105 away from the substrate holder 101 during heating.

[0033] In step S2, the control unit C measures the distortion of the substrate 105 while the substrate 105 is held by the substrate holding unit 101. The reason why the substrate 105 is held by the substrate holding unit 101 is so that the distortion of the deformed substrate holding unit 101 can be transmitted to the substrate 105 in the next step S3. The distortion of the substrate 105 is measured, for example, by measuring a pattern arranged on the surface of the substrate 105. Therefore, in this embodiment, the measurement result includes information on the amount of deformation in the in-plane direction of the surface of the substrate.

[0034] Next, the deformation process of the substrate 105 in step S3 will be described. With the substrate 105 held by the substrate holder 101, the control unit C supplies power to some (one or more specific heating units) of the multiple heating units 103 based on the shape data obtained by the measurement in step S2, as shown in FIG. 1(B2). This locally heats the phase change material 102, distorting the substrate holder 101 and the substrate 105 held thereon. The amount of distortion to be applied to the substrate 105 may be derived based on the shape data measured in step S2, or may be derived by adding a previously measured amount of distortion inherent in the substrate 105 to the shape data obtained by the measurement in step S2. Alternatively, the amount of distortion caused by substrate processing in a substrate processing apparatus using the holding device 100 may be determined in advance, and the amount of distortion to be applied to the substrate 105 may be derived so as to reduce the distortion caused by the substrate processing.

[0035] In the heating and deformation of the phase-change material 102 in step S3, as shown in FIG. 1B2, while the substrate 105 is held by the substrate holder 101, the power supply to each of the multiple heaters 103 is controlled to locally heat the phase-change material 102. At this time, in the area of ​​the substrate 105 where a large amount of shrinkage and distortion is desired, the temperature of the heater is increased or the heat input is increased so that a wide range of the phase-change material 102 exceeds the glass transition temperature Tg. Then, by gradually cooling, the phase-change material 102 in the range above the glass transition temperature Tg changes to a crystalline state and shrinks in volume. As a result, the localized shrinkage of the substrate holder 101 is transmitted to the substrate 105, distorting the substrate 105. The range of shrinkage due to the phase change to a crystalline state can be changed by adjusting the heating state of the heater, thereby controlling the distortion of the substrate 105.

[0036] 1(A1) to 1(A3), the control unit C measures the distortion of the substrate 105 in step S4, and determines whether the difference between the amount of distortion of the substrate 105 and the target amount of distortion is within an allowable range in step S5. In step S6, the control unit C determines whether the deformation of the phase change material 102 is within a correctable range, and repeats the process depending on the determination results of steps S5 and S6.

[0037] Example 2 1 shows a configuration in which deformation of the substrate or holding surface is controlled by the temperature or heat quantity of some of the multiple heating units 103. In contrast, in Example 2, as shown in Figures 2(A1) to 2(A3), the multiple heating units 103 have a larger number of heating units than in Example 1, and the number of heating units in the vicinity of the area to be deformed is driven ON / OFF according to the amount of deformation desired.

[0038] 10 can be applied to the control procedure in the second embodiment as well, as in the first embodiment. In FIG. 2(A2), as in FIG. 1(A2) of the first embodiment, contraction of the phase change material 102 is controlled by turning on a heating unit, among the multiple heating units 103, that is located near a portion of the substrate 105 that is to be recessed. As a result, as shown in FIG. 2(A3), the surface of the substrate holding unit 101 that holds the substrate can be recessed.

[0039] The differences between Example 1 and Example 2 will be described. In Example 1, the heat input amount of each of the multiple heating units 103 is controlled in multiple gradations. In contrast, in Example 2, the multiple heating units 103 are each controlled to be turned on / off, and the heating of the phase change material 102 is controlled by the density of the heating units that are turned on. In FIG. 2(A2), in step S3, the heating units that are turned on in the area where a large depression is desired are densely arranged, and the heating units 103 that are turned on in the area where a small depression is desired are sparsely arranged. In order to control the area where the temperature is raised by turning on / off the multiple heating units 103, it is desirable that the multiple heating units 103 be arranged more closely than the short-period wavelength of the periodic component in the substrate plane in the target shape or target distortion of the substrate 105.

[0040] 2(B1) to (B3) show deformation processing focusing on the in-plane direction. The details of the processing are the same as those in the above-mentioned FIGS. 1(B1) to (B3), so a description thereof will be omitted.

[0041] In addition, in this Example 2, instead of simply selecting a heating section to be heated from among the multiple heating sections 103, the temperature or heat quantity of each heating section may be changed simultaneously to control the phase change of the phase change material 102, as in Example 1.

[0042] Example 3 In Example 3, the phase change material 102 is heated from outside the substrate holder 101. FIG. 3(A1) shows an example of the configuration of Example 3. In FIG. 3(A1), the phase change material 102 is disposed inside the substrate holder 101, and the multiple heating units 1031 are disposed above the substrate holding surface of the substrate holder 101, sandwiching the substrate 105. The multiple heating units 1031 may be configured to irradiate the substrate holding surface with electromagnetic radiation, such as a laser, in order to locally heat the substrate from a distance. However, if the substrate holder 101 and the multiple heating units 1031 can be disposed close to each other, the multiple heating units 1031 may be configured to include electromagnetic induction heating or heaters. The multiple heating units 1031 may be configured to irradiate electromagnetic radiation that penetrates the substrate 105. In one example, if the substrate is a silicon wafer, the multiple heating units 1031 may be configured to irradiate infrared light that penetrates silicon. This allows the substrate holder 101 to simultaneously perform the measurement in step S2 and the deformation of the substrate in step S3 while holding the substrate 105 (or measurement substrate), which is a silicon wafer, thereby reducing errors associated with substrate transfer.

[0043] The control procedure of the third embodiment can be the same as that of the first and second embodiments, as shown in the flowchart of FIG. 10. A process for deforming the surface irregularities of the substrate 105 will be described with reference to FIGS. 3A1 to 3A3. In step S1, the control unit C heats and rapidly cools the phase change material 102 using the multiple heating units 1031 to turn it into an amorphous phase. In step S2, the control unit C measures the irregularities of the surface of the substrate 105 or the substrate holding surface of the substrate holding unit, which is the measurement target. Then, in step S3, the control unit C heats and slowly cools the heating unit corresponding to the desired portion of the phase change material 102 to a temperature equivalent to the glass transition temperature Tg, causing it to shrink. In step S4, the control unit C measures the shape of the measurement target, and in step S5, determines whether the difference between the deformation amount of the substrate 105 and the target deformation amount is within an allowable range. In step S6, the control unit C determines whether the phase change material 102 is within a deformable range, and repeats the process depending on the determination results of steps S5 and S6.

[0044] Next, a method for controlling the shape of the substrate 105 in the in-plane direction will be described with reference to FIGS. In step S1, the control unit C drives all of the heating units 1031 to heat the phase change material 102 to a temperature above the melting point Tm and then rapidly cools it. Rapid cooling causes the phase change material 102 to become amorphous and reach its largest volume. In this case, since the phase change material 102 reaches or exceeds its melting point, it is desirable to minimize the external force applied. Therefore, it is advisable to temporarily move the substrate 105 away from the substrate holder 101 during heating.

[0045] In step S2, while the substrate 105 is held by the substrate holding part 101, the control part C measures the distortion of the substrate 105. The substrate 105 is held by the substrate holding part 101 so that the distortion of the deformed substrate holding part 101 can be transmitted to the substrate 105 in the next step S3. The distortion of the substrate 105 is measured, for example, by measuring a pattern arranged on the surface of the substrate 105.

[0046] Next, in step S3, while the substrate 105 is held by suction on the substrate holder 101, the control unit C supplies power to one or more specific heating units among the plurality of heating units 1031 based on the shape data obtained by the measurement in step S2, as shown in FIG. 3(B2). This locally heats the phase change material 102. Then, slow cooling is performed, which deforms the phase change material 102 and distorts the substrate holder 101 and the substrate 105 held thereon by suction. As described above, in this case, the plurality of heating units 1031 emit electromagnetic radiation that passes through the substrate 105 or the measurement substrate.

[0047] As in the above-mentioned Figures 1(B1) to (B3), the phase change material 102 in the range above the glass transition temperature Tg changes into a crystalline phase and contracts in volume, and as a result, the local contraction of the substrate holding part 101 is transmitted to the substrate 105, causing distortion in the substrate 105.

[0048] 3(A1)-(A3) and 3(B1)-(B3), the heating unit 1031 is configured with multiple heating units, as in Example 1. However, the number of heating units may be one. In this case, the heating position of the phase-change material 102 may be changed by changing the relative position of the heating unit 1031 and the substrate holder 101. The relative position of the heating unit 1031 and the substrate holder 101 can be changed by driving one or both of the heating unit 1031 and the substrate holder 101 in the left-right and depth directions of the page in FIG. 3. This allows the heating position of the phase-change material 102 to be changed. If the heating unit 1031 is configured to irradiate electromagnetic radiation such as laser light, the heating position of the phase-change material 102 can be driven to any position using a deflection device such as a galvanometer scanner. That is, the heating unit 103 may include a galvanometer scanner that deflects electromagnetic radiation generated from a radiation source so that the electromagnetic radiation is irradiated onto one or more portions of the phase-change material 102.

[0049] In the heating unit 1031, the heat input to the phase-change material 102 may be controlled by a drawing device that partially blocks or reduces the light from the wide light that heats a wide range all at once. In this case, a liquid crystal shutter, a MEMS micromirror driving element, or the like is suitable as the drawing device.

[0050] FIG. 4 shows a configuration example of a substrate processing system 1 including a holding device 100 and a substrate processing apparatus 110 using the same. The holding device 100 has a substrate holding unit 101 and a phase change material 102. The substrate processing apparatus 110 has a processing unit 108 that processes a substrate 105 held by the holding device 100. The processing unit 108 includes a substrate processing mechanism 109 for substrate processing. In this embodiment, a heating unit 1031 and a displacement measurement unit 106 are disposed outside the substrate processing apparatus 110. As described above, the heating unit 1031 may include a single heating unit or multiple heating units. From the viewpoint of productivity of the substrate processing apparatus 110, it is desirable that the measurement steps of steps S2 and S4 and the heating steps of steps S1 and S3 be performed in parallel with the substrate processing at a position (below the substrate processing mechanism 109) in the substrate processing apparatus 110. However, due to limitations on the placement of the substrate processing mechanism 109, it may not be possible to place the displacement meter side unit 106 and the heating unit 1031 within the processing unit 108. Therefore, in FIG. 4 , the holding device 100 is placed outside the substrate processing apparatus 110, where the deformation process of the substrate holding surface is performed using the heating unit 1031 and the displacement measurement unit 106. After the deformation process is completed and the substrate is held, the substrate holding unit 101 of the holding device 100, together with the substrate 105, is carried into the substrate processing apparatus 110 by a transport mechanism (not shown). Thus, from the viewpoint of productivity, it is preferable that the holding device 100 be located within the substrate processing apparatus 110. However, as described above, depending on limitations on the placement of the substrate processing mechanism 109, the holding device 100 may be located outside the substrate processing apparatus 110. By placing the holding device 100 outside the substrate processing apparatus 100, dimensional limitations on the holding device 100 unit are alleviated, which may enable, for example, a more accurate displacement meter side unit to be configured.

[0051] Second Embodiment A substrate deformation method using the holding device 100 in the second embodiment will be described as Example 4 with reference to FIGS. 6(a) to 6(c).

[0052] Example 4 6(a), the substrate holding unit 101 of the holding device 100 has a plurality of convex protrusions 1011 that support a substrate. In a substrate processing apparatus, the plurality of protrusions 1011 are employed as a countermeasure to the problem of localized deformation of the substrate surface due to fine particles being trapped between the substrate and the substrate holding unit 101 when the substrate is held by the substrate holding unit 101. The plurality of protrusions 1011 come into contact with the substrate only at their apexes, thereby reducing the contact area with the substrate and reducing the probability of trapping particles.

[0053] The phase change material 102 is disposed on the upper surfaces of the plurality of protrusions 1011. In FIG. 6(a), the phase change material 102 is disposed only on the upper surfaces of the plurality of protrusions 1011, but as shown in FIG. 7, the phase change material 102 may be disposed not only on the plurality of protrusions 1011 but also on the surface of the substrate holding part 101. The arrangement of the phase change material 102 as shown in FIG. 7 can be achieved by forming a film of the phase change material 102 on the substrate holding part 101 by a film formation method such as sputtering. In this embodiment, the arrangement of the phase change material 102 on the plurality of protrusions 1011 may be either that shown in FIG. 6(a) or FIG. 7, and is designed appropriately in consideration of the processing method to be adopted, etc.

[0054] Furthermore, a protective layer (not shown) for protecting the phase change material 102 may be coated on the upper surface of the phase change material 102. In this case, the protective layer is preferably made of a material that allows electromagnetic radiation from the heating unit 1031 to pass through.

[0055] The operation leading to the concave and convex deformation of the substrate 105 in the fourth embodiment can be controlled according to the flowchart shown in FIG.

[0056] The heating unit 1031 and the substrate holding unit 101 are driven relatively in the left-right and depth directions of the page, thereby heating the phase change material 102 at the plurality of protrusions 1011. Alternatively, the phase change material 102 at the plurality of protrusions 1011 may be heated using a deflection device such as a galvanometer scanner. Alternatively, similar to the third embodiment, the heat input to the phase change material 102 may be controlled using a liquid crystal shutter, a MEMS micromirror driving element, or the like.

[0057] The control flow of the holding device 100 in Example 4 is the same as that in Example 3. First, in step S1, the phase change material 102 is made amorphous, and then the shape is measured in step S2. In the measurement in step S2, as in Example 1, the measurement target may be the surface of the substrate 105 held by the substrate holding unit 101, or the upper surfaces of the multiple protrusions 1011 when the substrate 105 is not held by the substrate holding unit 101.

[0058] As a measurement method, either a method using a displacement measuring unit 106 that measures local displacement as shown in Fig. 5(a) or a method using a planar displacement meter side unit 1061 that measures unevenness over a wide range all at once as shown in Fig. 5(b) may be adopted. As described in Example 1, in order to improve measurement accuracy, measurement using a planar displacement meter side unit that measures a wide range all at once is preferable because it can reduce measurement errors.

[0059] In step S3, based on the shape measurement result in step S2, the heating unit 1031 is used to heat the phase change material 102 in the area to be recessed to a temperature equivalent to the glass transition temperature Tg, causing it to shrink (FIG. 6(b)). Next, in step S4, the shape of the measurement target is measured, and in step S5, steps S3 to S6 are repeated until it is determined that the difference between the measured shape and the target shape is within the tolerance range. FIG. 6(c) shows an example of the controlled state of the phase change material 102 when the difference between the measured shape and the target shape is within the tolerance range.

[0060] In this embodiment, as shown in Figure 4, the heating of the phase change material 102 using the heating unit 1031 and the measurement of the shape of the phase change material 102 using the displacement measurement unit may also be performed outside the substrate processing apparatus.

[0061] Example 5 FIG. 8 illustrates an example of the arrangement of phase-change materials in Example 5. In FIG. 8, multiple phase-change materials 1022 are arranged inside the substrate holder 101. The multiple phase-change materials 1022 may be understood as, for example, the phase-change material 102 shown in FIG. 1 divided into multiple parts. By dividing the phase-change material into multiple parts, it is possible to pinpoint and heat only one or more of the multiple phase-change materials 1022 arranged in a desired location where unevenness or distortion is desired. This improves the controllability of deformation within the substrate 105 plane in the holding device 100. Furthermore, while the temperature distribution of the phase-change material 102 shown in FIG. 1 is continuous, the temperature changes of multiple phase-change materials 1022 are separated into step-like sections, thereby generating abrupt unevenness and distortion changes in the substrate plane. Furthermore, a separation wall may be arranged to reduce thermal conduction between adjacent phase-change materials 1022. Such a separation wall can separate the temperature changes between adjacent phase-change materials.

[0062] Example 6 The phase change material 102 disposed on each of the plurality of protrusions 1011 shown in FIG. 6(a) in relation to the fourth embodiment can be further divided into a plurality of regions. FIG. 11(a) is a plan view of one of the plurality of protrusions 1011 on the substrate holder 101, as viewed from the substrate side, and FIG. 11(b) is a side view of the protrusion 1011 shown in FIG. 11(a). As shown in FIG. 11(a), a plurality of (e.g., four) phase change materials 102 are disposed within one protrusion. As an example, in step S3, if only the phase change material 102 on the right side of FIG. 11(b) is driven (heat input), only the volume of the phase change material 102 on the right side contracts, as indicated by the dashed line. In this manner, by varying the amount of heat input to each of the plurality of phase change materials within the protrusion, the upper surface of the protrusion 1011 can be inclined. Note that, although FIG. 11(a) illustrates an example in which four phase change materials 102 are disposed on one protrusion, the number of phase change materials disposed is not limited to a specific number. However, in order to tilt the upper surface of the protrusion at any angle, it is desirable to arrange at least three phase change materials on one protrusion.

[0063] Another method for inclining the upper surface of the protrusion will be described with reference to FIG. 12. In FIG. 12, a single phase change material 102 is disposed on each of a plurality of protrusions 1011. Here, a distribution can be provided for the amount of heat input to this phase change material 102. For example, if a distribution is provided in step S3 so that the amount of heat input is higher on the left side of the phase change material 102 in FIG. 12, the amount of contraction increases in the phase change material 102 toward the left side of the phase change region 1021, and the upper surface of the protrusion 1011 can be inclined downward to the left.

[0064] Example 7 An example of relatively increasing the deformation amount of the protrusion 1011 will be described with reference to FIGS. 13(a) and 13(b).

[0065] In the above-described fourth embodiment (FIGS. 6(a) to 6(c)), the phase change material 102 is disposed on the upper end surface of the protrusion 1011, and the deformation of the substrate holding surface is realized by the volume change caused by the phase change of the phase change material 102. However, the amount of volume change of the phase change material 102 is limited. Therefore, in order to increase the amount of upward deformation of the phase change material 102, a protrusion void 107 is provided near the lower part of the phase change material 102 disposed on the protrusion 1011, as shown in FIG. 13(a). The expansion coefficient of the phase change material 102 due to the phase change is greater than the thermal expansion coefficient of the protrusion void 107. Therefore, when the phase change material 102 becomes amorphous and expands, the end of the phase change material 102 bends toward the protrusion void 107, as in bimetal deformation, as shown in FIG. 13(b). Accordingly, the amount of upward deformation of the phase change material 102 can be increased.

[0066] Third Embodiment In the substrate processing system 1 shown in FIG. 4, the substrate processing apparatus 110 using the holding device 100 can be any one of lithography apparatuses (exposure apparatus, imprint apparatus, charged particle beam lithography apparatus, etc.). The exposure apparatus is an apparatus that exposes a photoresist supplied on a substrate through an original to form a latent image corresponding to the pattern of the original in the photoresist. The imprint apparatus is an apparatus that forms a pattern on a substrate by curing an imprint material supplied on the substrate while bringing a mold (original) into contact with the imprint material. The charged particle beam lithography apparatus is an apparatus that forms a latent image in a photoresist supplied on a substrate by drawing a pattern on the photoresist with a charged particle beam.

[0067] Alternatively, the substrate processing apparatus 110 may be any one of a film forming apparatus (CVD apparatus, etc.), a processing apparatus (laser processing apparatus, etc.), and an inspection apparatus (overlay inspection apparatus, etc.). Alternatively, the substrate processing apparatus 110 may be a coating and developing apparatus (coater / developer) that applies a resist material (adhesion material) to a substrate as pre-processing for lithography processing and that performs development processing as post-processing for lithography processing.

[0068] To provide a concrete example, the following describes an example in which the substrate processing apparatus 110 is configured as an exposure apparatus. FIG. 14 shows the configuration of an exposure apparatus 110A that uses the holding device 100. As also shown in FIG. 4, the holding device 100 can be installed outside the exposure apparatus 110A. In the holding device 100, a deformation process of the substrate holding surface is performed using the heating unit 1031 and the displacement measurement unit 106. As described above, the heating unit 1031 may include a single heating unit or multiple heating units. After the deformation process is completed and the substrate is held, the substrate holding unit 101 of the holding device 100 is loaded into the exposure apparatus 110A together with the substrate 105.

[0069] Exposure apparatus 110A is an exposure apparatus that exposes each of multiple shot areas on a substrate, and is, for example, a step-and-scan scanning exposure apparatus that scans and exposes the substrate using slit light. Exposure apparatus 110A includes illumination optical system 10, mask stage 12, projection optical system 13, and control device 22. Here, the loaded substrate holder 101 functions as a substrate stage that moves in the X and Y directions. Control device 22 is configured, for example, by a computer device including a CPU and memory, and comprehensively controls exposure apparatus 110A. That is, control device 22 controls the process of transferring a pattern formed on mask 11, which is an original, onto substrate 105 (the process of scanning and exposing substrate 105). Also, here, the function of control unit C described above is assumed to be realized by control device 22.

[0070] The illumination optical system 10 uses a light-blocking member, such as a masking blade, included therein to shape light emitted from a light source (not shown) into a slit beam of light having, for example, a strip-like or arc-like shape that is long in the X direction, and illuminates a portion of the mask 11 with the slit beam. The mask 11 and the substrate 105 are held by a mask stage 12 and a substrate holder 101 (substrate stage), respectively, and are disposed at positions that are approximately optically conjugate with each other via the projection optical system 13 (the object plane and image plane of the projection optical system 13). The projection optical system 13 projects the pattern of the mask 11 onto each of a plurality of shot areas of the substrate 105 held by the substrate holder 101. Specifically, the projection optical system 13 has a predetermined projection magnification (e.g., 1 / 2 or 1 / 4), and projects the pattern formed on the mask 11 onto the substrate with the slit beam of light. The mask stage 12 and the substrate holding unit 101 are configured to be movable in a direction (e.g., the Y direction) perpendicular to the optical axis direction (Z direction) of the projection optical system 13, and are scanned relative to each other in synchronization with each other at a speed ratio according to the projection magnification of the projection optical system 13. This allows the irradiation area to be scanned in the Y direction on the substrate, and the pattern formed on the mask 11 to be transferred to a shot area on the substrate. This scanning exposure is then repeated sequentially for each of the multiple shot areas on the substrate while moving the substrate holding unit 101, thereby completing the exposure process for one substrate 105.

[0071] The details of the deformation process of the substrate holding surface of the holding device 100 are as explained in the first and second embodiments. The deformation process is preferably performed when the substrate 105 is replaced or when exposure to the substrate 105 is stopped due to various calibrations of the device.

[0072] <Embodiment of an article manufacturing method> The article manufacturing method according to an embodiment of the present invention is suitable for manufacturing articles such as microdevices, such as semiconductor devices, and elements having microstructures. The article manufacturing method according to this embodiment includes a step of transferring a pattern of an original onto a substrate using the above-described lithography apparatus (such as an exposure apparatus, imprint apparatus, or drawing apparatus), and a step of processing the substrate onto which the pattern has been transferred. Furthermore, this manufacturing method includes other well-known steps (such as oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, and packaging). The article manufacturing method according to this embodiment is advantageous over conventional methods in at least one of the performance, quality, productivity, and production cost of the article.

[0073] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0074] 100: holding device, 101: substrate holding unit, 102: phase change material, 103: heating unit, 105: substrate, C: control unit

Claims

1. a holder for holding an object; a phase change material that is disposed inside the holding portion or on the holding surface of the object, and that changes in phase between an amorphous phase and a crystalline phase and undergoes a volume change in accordance with the phase change; a control unit that controls heating of the phase change material using a heating unit that heats the phase change material so as to cause a volume change of the phase change material and thereby deform the holding surface; A holding device comprising:

2. The control unit a first step of heating the phase change material to a temperature exceeding the melting point using the heating unit and then cooling the phase change material to make the phase change material amorphous; a second step of heating a portion of the phase change material to a temperature exceeding the glass transition temperature using the heating unit and then cooling the portion to partially contract the volume of the phase change material; 2. The holding device according to claim 1, wherein the holding surface is deformed by performing the following.

3. The holding device according to claim 2 , wherein the control unit determines the part based on a measurement result of a shape of the holding surface or a surface of the object held by the holding unit.

4. 4. The holding device according to claim 3, wherein the measurement result includes information on an amount of deformation in an out-of-plane direction of the surface of the object held by the holding unit.

5. 4. The holding device according to claim 3, wherein the measurement result includes information on an amount of deformation in an in-plane direction of the surface of the object held by the holding unit.

6. 6. The holding device according to claim 3, further comprising a measuring unit that measures a shape of the holding surface or a surface of the object held by the holding unit.

7. the second step includes measuring a shape of the holding surface or a surface of the object held by the holding unit using the measuring unit after performing partial contraction of the phase change material; 7. The holding device according to claim 6, wherein the control unit repeats the second step until a difference between a target shape and the measured shape falls within an allowable range.

8. The heating unit includes a plurality of heating units, 8. The holding device according to claim 1, wherein the control unit controls the heat input amount of each of the plurality of heating units in a plurality of gradations.

9. The heating unit includes a plurality of heating units, The holding device according to claim 1 , wherein the control unit controls ON / OFF of each of the plurality of heating units.

10. The holding device according to claim 8 or 9, wherein the plurality of heating units are arranged inside the holding unit.

11. 11. The holding device according to claim 10, wherein each of the plurality of heating sections includes a heater element made of a resistive heat generating material that generates heat when supplied with power.

12. The holding device according to claim 10 , wherein each of the plurality of heating sections includes an induction heating element that heats using electromagnetic induction generated by a coil disposed around a ferromagnetic material.

13. The holding device according to claim 1 , wherein the heating unit is disposed above and spaced apart from the holding surface.

14. The holding device according to claim 13 , wherein the heating unit heats the phase change material by irradiating the holding surface with electromagnetic radiation.

15. 15. The holding device according to claim 13, wherein the holding surface has a plurality of protrusions, and the phase change material is disposed on an upper surface of each of the plurality of protrusions.

16. 16. The holding device of claim 13, wherein the heating unit includes a galvanometer scanner that deflects electromagnetic radiation generated from a radiation source so that the electromagnetic radiation is irradiated onto each of one or more portions of the phase change material.

17. The holding device according to claim 1 , wherein a plurality of the phase change materials are arranged inside the holding portion.

18. 18. The holding device of claim 17, further comprising a separation wall disposed between adjacent phase change materials to reduce heat conduction between the phase change materials.

19. the holding surface has a plurality of protrusions, and a plurality of phase change materials are disposed inside the plurality of protrusions, the control unit tilts the upper surface of the protrusion by varying the amount of heat input to each of the plurality of phase change materials in the protrusion; 15. A holding device according to claim 13 or 14.

20. the holding surface has a plurality of protrusions, and a single phase change material is disposed inside each of the plurality of protrusions; the control unit inclines the upper surface of the protrusion by providing a distribution in the amount of heat input to the phase change material in the protrusion; 15. A holding device according to claim 13 or 14.

21. The holding device of claim 13 or 14, characterized in that the holding surface has a plurality of protrusions, a phase change material is disposed inside each of the plurality of protrusions, and a void is provided near the bottom of the phase change material to increase the deformation amount of the phase change material.

22. 1. A lithographic apparatus for forming a pattern on a substrate, comprising: A lithographic apparatus comprising a holding device according to any one of claims 1 to 21, for holding the object, the substrate.

23. forming a pattern on a substrate using a lithographic apparatus according to claim 22; processing the substrate on which the pattern has been formed in the process; and manufacturing an article from the processed substrate.

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