JP2006013211A - Temperature control unit and exposure device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation panel capable of controlling the radiation of radiation as heat movement between bodies in a vacuum environment. <P>SOLUTION: The temperature control unit which controls the temperature of a body is equipped with the radiation panel which is arranged opposite to the body and whose angle can be changed, a measurement part which measures surface temperature of the body, a measurement part which measures surface temperature of the radiation plate, and an angle control unit which changes the angle of the radiation plate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a temperature control apparatus using radiant heat transfer and an exposure apparatus used in a semiconductor manufacturing process, which relates to a projection exposure apparatus that projects and transfers a reticle pattern onto a silicon wafer. In particular, the present invention relates to an EUV exposure apparatus that is an in-vacuum exposure apparatus that uses exposure light having a wavelength of about 13 to 14 nm, which is EUV light (Extreme Ultraviolet) as a light source.

  In the current semiconductor integrated circuit manufacturing technology, a method is widely employed in which a very fine pattern formed on a reticle is projected onto a wafer coated with a resist by reduction projection with visible light or ultraviolet light. However, in the current exposure using visible light or ultraviolet light, since the pattern size to be transferred is approaching the diffraction limit, it is becoming difficult in principle to transfer a finer pattern. Accordingly, reduction projection exposure using extreme ultraviolet light (hereinafter referred to as EUV light) having a wavelength of 13 to 14 nm, which is shorter than ultraviolet light, has been proposed as the pattern size becomes finer.

  On the other hand, it is necessary to change the exposure environment as the wavelength becomes shorter. Since EUV light has a short wavelength, when exposure is performed in air or in an atmosphere of nitrogen as in lithography using a conventional KrF excimer laser (wavelength 248 nm) or ArF excimer laser (wavelength 193 nm), the exposure light becomes oxygen molecules or It is absorbed by nitrogen molecules. Therefore, it is necessary to perform EUV exposure in a vacuum.

  In addition, various devices serving as heat sources such as a linear motor such as a reticle stage and a wafer stage and a sensor such as a CCD for position measurement are arranged in the exposure apparatus, and thermal expansion caused by the heat generated by these devices By thermal deformation, the relative relationship between the optical system and the sensor is changed.

As a temperature control method in a conventional exposure apparatus, a method by which air (gas) whose temperature is controlled in a chamber is blown to an object is often employed, and liquid cooling with a temperature-controlled refrigerant or the like is applied to a heat source device. The temperature is also controlled by conduction.
JP 2004-068626 A

  However, as the exposure environment becomes a vacuum environment, temperature control by gas transfer becomes impossible, and the heat transfer method in the vacuum environment becomes radiation and conduction. Furthermore, the only heat transfer between objects without inclusions is radiation.

  The thermal energy generated in the vacuum chamber moves in the chamber by radiation, but since the chamber is a closed system, reflection is repeated until it is absorbed. Therefore, the only way to insulate the radiant heat is to cut off the radiant heat using a conventional radiant panel or the like. However, in the exposure apparatus, there are many heat sources, and since the apparatus is complicated, it is difficult to shut off all of them, and it is difficult to release heat to the outside of the chamber.

  Furthermore, since there are cases where the heat source moves during scanning, such as a reticle, the radiated heat direction is not uniform.

  An object of this invention is to provide the radiation panel which can control the radiation heat-transfer direction which is the heat transfer between the objects in a vacuum environment.

  The invention according to claim 1 is a radiation panel in which the radiation plate is gradient-controllable, and has a measurement mechanism that can measure the surface temperature of the heating element and a measurement mechanism that measures the surface temperature of the radiation plate. To do.

  According to the radiant panel of the first aspect, the amount of radiant heat can be calculated from the temperature difference with the radiant plate by measuring the surface temperature of the heating element. Further, the direction of the radiated heat source can be specified from the temperature distribution, and the reflection direction of the radiant heat can be controlled by controlling the angle of the radiation plate. Further, by providing a heat exhaust mechanism such as a cooling unit outside the chamber in the direction of reflection of radiant heat, heat can be effectively discharged to the outside.

  The radiation panel according to claim 2 is the radiation panel according to claim 1, wherein a plurality of fine radiation plates are arranged side by side.

  According to this, the reflection direction of radiant heat can be controlled more accurately by controlling a plurality of radiation plates.

  The invention according to claim 3 is the radiation panel according to claim 1 or 2, further comprising a temperature control mechanism capable of controlling the surface temperature of each radiation plate.

  According to this, by measuring the heating element surface temperature according to claim 1, the direction of the heating element and the amount of heat radiation are specified, and the temperature difference is generated by setting the temperature of the radiation plate lower than the heat source. Radiant heat is efficiently transmitted to the radiation panel.

  According to a fourth aspect of the present invention, there is provided an exposure apparatus for transferring a pattern image on a reticle to a substrate (wafer) coated with a photosensitive agent through a projection reflection optical system by means of an illuminating unit. It has the radiation panel for radiant heat reflection as described in above.

  According to this, the position of the heat source can be specified by the heating element surface temperature measuring unit according to claim 1, and the radiation heat can be reflected in a predetermined direction by controlling the angle of the radiation plate. Further, by using the divided radiation plate according to claim 2, it is possible to reflect with higher accuracy.

  According to a fifth aspect of the present invention, in the exposure apparatus according to the fourth aspect, the radiation panel is arranged so as to face a region that does not block exposure light on an optical element such as a reticle, wafer, or mirror. And

  According to this, by measuring the radiant heat according to claim 1, the heat distribution of the mirror or the like can be grasped, and the angle control and the temperature control of the divided radiation plate according to claim 2 are performed accordingly. Therefore, the temperature unevenness on the mirror can be reduced and the temperature can be adjusted.

  According to a sixth aspect of the present invention, in the exposure apparatus according to the fourth aspect of the present invention, the radiation panel is disposed opposite to a reticle or the like that is a heat source that moves during exposure.

  According to this, even with respect to a heat source that moves like a reticle, radiant heat can be reflected in a predetermined direction by actively controlling the gradient of the angle of the radiant panel.

  According to a seventh aspect of the present invention, in the exposure apparatus according to the fourth aspect, the amount of heat generated by the exposure heat or the position of the heating element is predicted in advance, and based on this, the radiation panel is controlled. To do.

  According to this, it is possible to easily control the radiant heat reflection by predicting in advance the amount of heat generation, the position of the heating element, and the moving process of the heating element, and controlling the radiation panel based on the prediction.

  According to the radiant panel according to the present invention, the reflection direction of radiant heat can be controlled, and temperature control and exhaust heat can be performed efficiently. Further, according to the in-vacuum exposure apparatus according to the present invention, the moving direction of the radiant heat that is the heat transfer means in the vacuum can be positively controlled, and the temperature adjustment and the exhaust heat can be efficiently performed.

  Examples of the present invention will be described below.

  The structure of a present Example and a radiation panel is shown to FIGS.

  In FIG. 1, an excitation laser 1 irradiates a light source material, which is a light emitting point of a light source, toward a gasified, liquefied, and atomized gas point, and emits light by exciting the light source material atoms with plasma, thereby producing a YAG solid. Use a laser or the like. The light source light emitting unit 2 has a structure in which a vacuum is maintained inside.

  A light source A indicated by 2A indicates a light emission point of an actual exposure light source. The light source mirror Aa indicated by 2Aa is arranged as a hemispherical mirror at the center of the light source A indicated by 2A in order to collect and reflect all spherical light from the light source A indicated by 2A in the light emitting direction. Xe (liquefaction, spray, gas) 2Ab causes liquefied Xe or liquefied Xe spray or Xe gas as a light emitting element to protrude from the point of light source A indicated by 2A by nozzle 2Ae. The vacuum chamber 3 stores the entire exposure apparatus and allows the vacuum pump 4 to maintain a vacuum state.

  The exposure light introducing unit 5 is constituted by mirrors A to D shown by 5A to 5D, introduces and molds the exposure light from the light source light emitting unit 2, and homogenizes and shapes the exposure light. An original plate 6A, which is a reflection original plate of an exposure pattern, is mounted on the movable part on the reticle stage 6. The reduction projection mirror optical system 7 reduces and projects the exposure pattern reflected from the original 6A, sequentially projects and reflects it on the mirrors A to E indicated by 7A to 7E, and is finally reduced and projected at a specified reduction ratio.

  The wafer stage 8 is a six-axis drive in the XYZ, tilt around the XY axes, and rotation around the Z axis in order to position the wafer 8A, which is an Si substrate that exposes the pattern reflected by the original 5A, at a predetermined exposure position. Positioning control is possible. The reticle stage support 9 supports the reticle stage 5 with respect to the apparatus installation floor. The projection system main body 10 supports the reduction projection mirror optical system 7 with respect to the apparatus installation floor. The wafer stage support 11 supports the wafer stage 8 against the apparatus installation floor. Between the reticle stage 5 and the reduction projection mirror optical system 7, and between the reduction projection mirror optical system 7 and the wafer stage, which are separately and independently supported by the reticle stage support 9, projection system main body 10 and wafer stage support 11 described above. Between 8, there is provided means (not shown) for measuring the relative position and maintaining and controlling the relative position continuously. The reticle stage support 9, the projection system main body 10, and the wafer stage support 11 are provided with mounts (not shown) that insulate vibrations from the apparatus installation floor.

  The reticle stocker 12 temporarily stores a reticle 6A, which is an original plate, from the outside of the apparatus, and stores a reticle in a sealed state in accordance with different patterns and different exposure conditions. The reticle changer 13 selects and transports a reticle to be used from the reticle stocker 12. The reticle alignment unit 14 is composed of a rotating hand that can rotate around the XYZ and Z axes, receives the original 6A from the reticle changer 13, and rotates it 180 degrees to the reticle alignment scope 15 provided at the end of the reticle stage 6 for reduction. Alignment is performed by finely moving the original plate 6A in the XYZ axis rotation direction with respect to the alignment mark 15A provided on the basis of the projection mirror optical system 7. The original 6A after alignment is chucked on the reticle stage 6.

  The wafer stocker 16 temporarily stores the wafer 8A inside the apparatus from the outside of the apparatus, and a plurality of wafers are stored in a storage container. The wafer transfer robot 17 selects the wafer 8A to be exposed from the wafer stocker 16, and carries it to the wafer mechanical pre-alignment temperature controller 18. The wafer mechanical pre-alignment temperature controller 18 adjusts the wafer feed in the rotational direction and simultaneously adjusts the wafer temperature to the exposure apparatus internal temperature adjustment temperature. The wafer feeding hand 19 feeds the wafer 8 </ b> A aligned and temperature-controlled by the wafer mechanical pre-alignment temperature controller 18 to the wafer stage 8.

  The gate valves 20 and 21 are gate opening / closing mechanisms that carry in a reticle and wafer from the outside of the apparatus. The gate valve 22 is also opened and closed only when the wafer stocker 16 and the wafer mechanical pre-alignment temperature controller 18 space and the exposure space are separated by a partition in the apparatus, and the wafer 8A is transferred and carried out.

  As described above, the separation by the partition wall makes it possible to minimize the volume once released to the atmosphere when the wafer 8A is transferred to and from the outside of the apparatus, and to quickly achieve a vacuum equilibrium state.

  Here, the radiation panel 23 is disposed opposite to a linear motor which is a heat source. The angle of the radiation plate is adjusted so that incident radiant heat is reflected to the cooling unit 24. The cooling unit 24 concentrates radiant heat from the heat source here. A thing with a low emissivity is desirable, and substantially absorbs incident radiant heat. The absorbed heat is heat-exchanged out of the chamber through the refrigerant by 25 refrigerant pipes. The refrigerant pipe 25 connects the inside and outside of the vacuum chamber and allows the refrigerant to flow therethrough.

  FIG. 2 shows a configuration example of the radiation panel.

  The radiation panel 27 is disposed to face the heating element 26. The temperature measuring unit 28 is a radiation thermometer and can measure the surface temperature of the heating element 26. Based on the data measured by the temperature measurement unit 28, the angle / temperature adjustment control unit 29 controls the angle of the radiation plate 30 so that the reflection direction of the radiant heat is directed toward the cooling unit 29.

  According to the above embodiment, the radiation plate surface temperature is controlled in accordance with the surface temperature / heat generation amount of the heating element, and the amount of heat transferred is determined. Thereafter, the reflection direction of the radiant heat can be determined by controlling the gradient of the radiation plate. In addition, since the radiation plate gradient can be controlled, even when the heating element moves like a reticle, the reflection direction of the radiant heat can be controlled to be constant by synchronously controlling the radiation plate gradient.

  In the above embodiment, the reflection projection type exposure apparatus using EUV as the exposure light source has been exemplified. However, the present invention is not limited to this, and can be applied to, for example, an X-ray exposure apparatus and an electron beam exposure apparatus. It can be applied to a conventional lens projection exposure apparatus using an excimer laser or the like.

FIG. 1 is an overall view of an exposure apparatus shown in an embodiment. The schematic longitudinal cross-sectional view which shows the structure of the temperature control apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Excitation laser 2 Light source light emission part 2A Light source A
2Aa Light source mirror Aa
2Ab Xe (liquefaction, spray, gas)
2Ae Nozzle 3 Vacuum chamber 4 Vacuum pump 5 Exposure light introduction part 5A Mirror A
5B Mirror B
5C Mirror C
5D Mirror D
5E Mirror barrel 5F Mirror support 6 Reticle stage 6A Master 7 Reduction projection mirror optical system 7A Mirror A
7B Mirror B
7C Mirror C
7D Mirror D
7E Mirror E
DESCRIPTION OF SYMBOLS 8 Wafer stage 8A Wafer 9 Reticle stage support body 10 Exposure apparatus main body 11 Wafer stage support body 12 Reticle stocker 13 Reticle changer 14 Reticle alignment unit 15 Reticle alignment scope 16 Wafer stocker 17 Wafer transfer robot 18 Wafer mechanism pre-alignment temperature controller 19 Wafer Feeding hand 20 Gate valve 21 Gate valve 22 Gate valve 23 Radiation panel 24 Cooling unit 25 Refrigerant piping 26 Heating element 27 Radiation panel 28 Temperature measurement unit 29 Radiation plate 30 Angle / temperature control unit 31 Cooling unit

Claims (7)

  A temperature adjustment device that adjusts the temperature of an object, the radiation panel being arranged opposite to the object and capable of changing the angle of the radiation plate, a measuring unit that measures the surface temperature of the object, and a radiation plate A temperature control device comprising: a measurement unit that measures a surface temperature; and an angle control unit that changes an angle of the radiation plate.   The temperature control device according to claim 1, wherein the radiation panel is configured by a plurality of radiation plates, and individual angle control is possible.   The temperature control device according to claim 1, wherein the temperature of the radiation panel is adjustable.   An exposure apparatus for transferring a reticle pattern onto a photosensitive substrate via a projection reflection optical system, comprising the radiation panel for temperature control according to claim 1.   The exposure apparatus according to claim 4, wherein the radiation panel is disposed in a region that does not block exposure light.   The exposure apparatus according to claim 4, wherein the radiation panel is disposed to face a moving object.   An angle changing means for predicting in advance the amount of heat given to the reticle or photosensitive substrate during exposure or the amount of heat generated by the object, and changing the angle of the radiation plate based on the prediction result, and temperature control for controlling the temperature of the copying plate 5. An exposure apparatus according to claim 4, further comprising means.

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