JP2006080184A - Substrate transfer device, exposure device and substrate transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer device or the like correctly controlling the temperature of a substrate from the first exposure upon starting the exposure or upon reopening after the interruption of the exposure. <P>SOLUTION: Upon starting or resuming after interruption of exposure, a temperature raising means is constituted so that the operation of the temperature raising means is started before receiving the substrate, whereby the substrate transfer device is provided which raises the temperature of substrate to a predetermined level from the first sheet feed. Accordingly, the substrate temperature control through the transfer device becomes correct, and variety in the temperatures of each substrates is reduced whereby the exposure with a high accuracy is effected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exposure apparatus used for lithography such as a semiconductor integrated circuit and a substrate transfer apparatus that supplies a substrate such as a wafer and a reticle (mask) to such an exposure apparatus. In particular, the present invention relates to an exposure apparatus that uses a charged particle beam such as an electron beam or an ion beam, or an X-ray to perform exposure under vacuum.

  In an apparatus that performs exposure in a vacuum atmosphere, such as an electron beam exposure apparatus or an X-ray exposure apparatus, the wafer and reticle (mask) are taken out from a cassette placed in an air atmosphere and pre-aligned by a pre-aligner apparatus or the like. Then, it is transferred to a chamber called a load lock chamber or a load chamber. A vacuum pump is attached to the load lock chamber, and the chamber can be evacuated. In the load lock chamber, a wafer or reticle (mask) is received from the pre-aligner under normal pressure, and after the chamber is evacuated, these are moved into the exposure apparatus.

  Normally, in the case of a wafer, when the load lock chamber is evacuated, the temperature of the wafer placed in the chamber is reduced by about 2 to 4 ° C. due to adiabatic expansion of the gas. When the temperature decreases in this way, the wafer may be distorted by the temperature change. In one example, in a Si wafer having a diameter of 200 mm, a dimensional change of about 0.5 μm occurs with a temperature change of 1 ° C. Such a dimensional change makes it impossible to obtain a highly accurate pattern. Therefore, it is necessary to wait for several tens of minutes until the temperature rises to the original temperature, or to perform alignment again and again before exposure.

For this reason, the wafer W is heated in advance by a lamp after completion of pre-alignment in the atmosphere. As a result, when evacuating in the load lock chamber, even if the temperature of the wafer placed in the chamber decreases due to adiabatic expansion of the gas, the wafer temperature returns to the original standard temperature. There is no change.
JP 2003-31470 A

  In the above apparatus, several to several tens of wafers are placed in a wafer cassette. When this wafer is exposed by the exposure apparatus, the wafer is sent out at a substantially constant interval, and each wafer is heated and then exposed. However, there is a heat capacity around the temperature raising means, and the first wafer is heated when the temperature raising means has not been heated for a while at the start of exposure or at the time of resumption after exposure interruption. In some cases, the amount of heat is consumed to heat the surrounding environment, and the amount of heat actually transmitted to the wafer is reduced. As a result, there is a problem that the temperature increase of the first few wafers becomes smaller than required.

  The present invention has been made in view of the above problems, and the temperature raising means is configured to start the operation of the temperature raising means before receiving the substrate at the start of exposure or at the time of restart after interruption of exposure. Therefore, an object of the present invention is to provide a substrate transport apparatus capable of increasing the substrate temperature from the first sheet, an exposure apparatus equipped with such a substrate transport apparatus, and a substrate transport method.

  In order to solve the above-mentioned problem, a substrate transport apparatus that includes a temperature raising unit that raises the temperature of each substrate and supplies the substrate to an exposure apparatus that forms a pattern under vacuum. When the operation is performed after an interval equal to or greater than the operation interval, the substrate transport apparatus (Claim 1) is provided in which the operation of the temperature raising unit is started before the substrate is received. According to the present invention, at the start of exposure or at the time of resumption after exposure interruption, the temperature raising means is configured to start the operation of the temperature raising means before receiving the substrate. It is possible to provide a substrate transfer apparatus capable of a predetermined increase in temperature. Therefore, the substrate temperature control by the transfer device becomes accurate, and the temperature variation from substrate to substrate is reduced.

  The substrate transport apparatus (Claim 2) according to claim 1, wherein the substrate is heated in the atmosphere before entering the vacuum chamber. In the present invention, it is possible to provide a substrate transfer apparatus that raises the temperature of a substrate with a simple configuration.

  The substrate transport apparatus (Claim 3) according to claim 1 or 2, wherein the temperature raising means is a lamp. In the present invention, it is possible to provide a substrate transfer apparatus that can efficiently raise the temperature of a substrate in a non-contact manner.

  4. The substrate transfer apparatus according to claim 1, wherein the temperature raising means raises the temperature of the substrate by a temperature substantially equal to a decrease in the temperature of the substrate due to adiabatic cooling under vacuum. (Claim 4) is provided. In the present invention, the temperature decrease due to adiabatic cooling under vacuum is accurately corrected, and highly accurate temperature management becomes possible.

  An exposure apparatus for transferring a pattern on a reticle substrate (including a mask substrate) onto a wafer substrate using an energy beam under vacuum, comprising the substrate transfer apparatus according to claim 1. An exposure apparatus (claim 5) is provided. In the present invention, at the start of exposure or at the restart after exposure interruption, the temperature raising means is configured to start the operation of the temperature raising means before receiving the substrate. It is possible to provide an exposure apparatus capable of a predetermined increase. Accordingly, the substrate temperature control by the transfer device becomes accurate, the variation in temperature between the substrates is reduced, and high-precision exposure can be performed.

  Also, there is provided a substrate transport method comprising a temperature raising means for raising the temperature of each substrate, and supplying the substrate to an exposure apparatus for forming a pattern under vacuum, wherein the temperature raising means is set at a predetermined operating interval or more. In the case of operating after the interval, the substrate transport method (Claim 6) is characterized in that the operation of the temperature raising means is started before the substrate is received. In the present invention, at the start of exposure or at the time of resumption after exposure interruption, the temperature raising means starts the operation of the temperature raising means before receiving the substrate. It is possible to provide a substrate carrying method capable of a predetermined rise.

  As is apparent from the above description, according to the present invention, at the start of exposure or at the restart after exposure interruption, the temperature raising means is configured to start the operation of the temperature raising means before receiving the substrate. Therefore, it is possible to provide a substrate transfer apparatus that can increase the substrate temperature from the first sheet. Accordingly, the substrate temperature control by the transfer device becomes accurate, the variation in temperature between the substrates is reduced, and high-precision exposure can be performed.

  Hereinafter, it demonstrates, referring drawings. FIG. 1 is a diagram schematically illustrating a substrate transfer apparatus according to an embodiment of the present invention. FIG. 2 is a view showing an outline of an imaging relationship and a control system in the entire optical system of an exposure apparatus provided with the substrate transport apparatus of FIG. FIG. 3 is a diagram for explaining the sequence of the transport apparatus according to the embodiment of the present invention.

  First, the configuration of the entire exposure apparatus will be described with reference to FIG. An optical barrel 101 is disposed on the electron beam exposure apparatus 100. A vacuum pump (not shown) is connected to the optical barrel 101, and the inside of the optical barrel 101 is evacuated.

  An electron gun 103 is disposed above the optical lens barrel (including the mask chamber) 101 and emits an electron beam downward. Under the electron gun 103, a condenser lens 104, an electron beam deflector 105, and a mask M are arranged in this order. The electron beam emitted from the electron gun 103 is converged by the condenser lens 104, and then sequentially scanned in the horizontal direction in the figure by the deflector 105, and each small region (subfield) of the mask M within the field of view of the optical system. ) Lighting is performed. The illumination optical system also has a beam shaping aperture, a blanking aperture, etc. (not shown).

  The mask M is fixed to the chuck 110 provided on the mask stage 111 by electrostatic adsorption or the like. The mask stage 111 is placed on the mount body 116.

  A driving device 112 shown on the left side of the drawing is connected to the mask stage 111. The driving device 112 is connected to the control device 115 via the driver 114. The mask stage 111 is provided with a laser interferometer 113 shown on the right side of the drawing. The laser interferometer 113 is connected to the control device 115. Accurate position information of the mask stage 111 measured by the laser interferometer 113 is input to the control device 115. Based on this, a command is sent from the control device 115 to the driver 114, and the drive device 112 is driven. In this way, the position of the mask stage 111 can be accurately feedback controlled in real time.

  Below the mount body 116, a wafer chamber 106 (vacuum chamber) is shown. A vacuum pump (not shown) is connected to the wafer chamber 106 to evacuate the chamber. A wafer transfer mechanism (wafer loader) including a vacuum load chamber 33, a load lock chamber 27, and the like is connected to the wafer chamber 106. This wafer transfer mechanism will be described later.

  A projection optical system barrel (not shown) in the wafer chamber 106 is provided with a projection lens 124, a deflector 125, and the like. Further, a wafer stage (precision device) 131 is placed on the bottom surface of the wafer chamber 106 below. A chuck 130 is provided above the wafer stage 131, and the wafer W is fixed by electrostatic adsorption or the like.

  The electron beam that has passed through the mask M is converged by the projection lens 124. The electron beam that has passed through the projection lens 124 is deflected by the deflector 125, and an image of the mask M is formed at a predetermined position on the wafer W. The projection optical system also has various aberration correction lenses, a contrast aperture (not shown), and the like.

  A driving device 132 shown on the left side of the drawing is connected to the wafer stage 131. The driving device 132 is connected to the control device 115 via the driver 134. The wafer stage 131 is provided with a laser interferometer 133 shown on the right side of the drawing. The laser interferometer 133 is connected to the control device 115. Accurate position information of the wafer stage 131 measured by the laser interferometer 133 is input to the control device 115. Based on this, a command is sent from the control device 115 to the driver 134, and the drive device 132 is driven. In this way, the position of the wafer stage 131 can be accurately feedback controlled in real time.

  Next, a substrate transfer device of the exposure apparatus will be described with reference to FIG. As shown in FIG. 1, a wafer cassette (container) 10 in which a plurality of wafers are stored, a first pre-aligner 20, and a transfer robot arm 25 are arranged in the atmosphere. A lamp 21 is disposed below the wafer W. The lamp 21 irradiates the lower surface of the wafer W.

  The first pre-aligner 20 includes a rotatable wafer support 22 (not shown) and a sensor 23 (not shown) for detecting the position of a notch formed on the outer periphery of the wafer W. The wafer W is supported by a wafer support portion 22 (not shown), and the position of the notch of the wafer W is detected by a sensor 23 (not shown) while the support portion is rotated one or more times.

  The first pre-aligner 20 is disposed in the vicinity of the load lock chamber 27. A gate valve 29 is provided at the inlet of the load lock chamber 27. The load lock chamber 27 is connected to the wafer vacuum load chamber 33 via the gate valve 31. A wafer transfer vacuum robot arm 35 is disposed in the wafer vacuum load chamber 33. The wafer vacuum load chamber 33 is connected to the pre-aligner chamber 41 via the gate valve 39. A second pre-aligner 43 is provided in the chamber 41. The wafer vacuum load chamber 33 is connected to the wafer chamber 106 of the exposure apparatus 100 via the gate valve 45. A wafer stage 131 is provided in the chamber 106, and a wafer holder 130 is provided on the wafer stage 131.

  Next, the transfer procedure of the wafer W will be described. First, the wafer W is taken out from the cassette 10 by the wafer transfer robot arm 25 and transferred onto the rotation support portion 22 (not shown) of the first pre-aligner 20. Then, pre-alignment of the wafer W is performed. During pre-alignment, as described above, the wafer W is supported by the rotation support unit 22 (not shown) and rotates one or more times. The pre-alignment time is about 4 seconds.

  After the pre-alignment is completed, the wafer W is taken out from the first pre-aligner 20 by the robot arm 25 and stopped at the upper part of the lamp 21. During this time, the lamp 21 is irradiated, and the lower surface of the wafer W is irradiated with the lamp 21 and heated. This wafer W is the first wafer W after starting the exposure apparatus, is the first wafer W after exchanging the wafer cassette 10, or the first wafer after the operation is interrupted for some reason In the case of W, the lamp 21 is irradiated before the wafer W reaches the upper part of the lamp 21.

  Next, the wafer heated by the robot arm 25 is taken out, the gate valve 29 is opened, and the wafer is transferred to the load lock chamber 27. Then, the gate valve 29 is closed and the load lock chamber 27 is evacuated. At this time, the temperature of the wafer W decreases due to the adiabatic expansion of the gas. However, since the temperature of the wafer is increased in advance by that amount, even if the temperature is decreased, it becomes the original temperature. When the target vacuum degree is reached, the gate valve 31 on the wafer vacuum load chamber 33 side is opened, and the wafer transfer vacuum robot arm 35 in the chamber 33 is used to take out the wafer W from the load lock chamber 27. Then, the gate valve 31 is closed.

  Thereafter, the gate valve 39 is opened, and the wafer is transferred to the second pre-aligner 43 in the pre-aligner chamber 41 by the wafer transfer vacuum robot arm 35 to perform more accurate pre-alignment. After the alignment is completed, the wafer is taken out by the wafer transfer vacuum robot arm 35, the gate valve 45 is opened, and the wafer is placed on the holder 130 on the wafer stage 131 in the wafer chamber 106. After the exposure operation is completed, the wafer W is taken out of the stage 131 by the wafer transfer vacuum robot arm 35 and returned to the cassette 10 through the load lock chamber 27.

  Next, the substrate transfer method according to the embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows the relationship between the position of the wafer W transferred for heating and the on / off state of the lamp 21. W1 represents the first wafer to be exposed, and W2 and W3 represent the second and third wafers, respectively. When the transfer sequence starts, first, preheating is performed. The lamp 21 is turned on, the environment around the lamp 21 is heated, and after heating for a predetermined time, the lamp 21 is turned off. At this time, the wafer W1 has not yet come over the lamp.

  Next, the wafer W 1 is transferred onto the lamp 21 by the wafer transfer robot 25. At this time, since the temperature around the lamp 21 is warmed by the preheating, much of the heat used for heating the wafer is consumed to raise the temperature around the lamp and is necessary to raise the temperature of the wafer W1. A situation where the amount of heat is insufficient is avoided. The wafer W1 stays on the lamp 21 for a predetermined time and is heated. Thereafter, the wafer W1 is transferred to the load lock chamber 27 by the wafer transfer robot 25. When the predetermined time has elapsed, the second wafer W2 is similarly transferred onto the lamp 21 by the wafer transfer robot 25. Similar to the wafer W1, it stays on the lamp 21 for a predetermined time, and after being heated, is transferred to the load lock chamber 27 by the wafer transfer robot 25. When the predetermined time has elapsed, the same operation is performed on the third wafer W3.

  In the above-described embodiment, the preheating is performed independently of the normal heating before the first wafer W1 is directly above the lamp. However, as shown by the dotted line in FIG. 3, this preheating is performed on the first wafer W1. The heating time may be lengthened. This can be realized by setting the heating start time earlier than usual, or delaying the end time, or both. By adopting such a system, the same effect can be obtained without providing preheating independently.

  In the above embodiment, the substrate is a wafer substrate. However, the substrate may be another substrate including a reticle (mask). Although there is a difference in the amount of heat applied to the substrate, the operation can be performed in exactly the same manner as in the case of the wafer substrate, and the same effect can be expected. Moreover, in the said Example, although it heats with a lamp after positioning with a 1st pre-aligner, the same effect is acquired even if it heats in another place. For example, heating may be performed during work at the first pre-aligner. Further, although a lamp is shown as an example of the temperature raising device, other devices such as a device that contacts a temperature control plate set to a predetermined temperature, a device that blows hot air, and the like may be used. Furthermore, in the said Example, although the example of the preheating which adds a fixed calorie | heat amount was shown, changing the calorie | heat amount to heat can also be considered.

It is a figure which illustrates typically the substrate conveyance apparatus concerning an embodiment of the invention. It is a figure which shows the outline of the imaging relationship in the whole optical system of an exposure apparatus provided with the board | substrate conveyance apparatus of FIG. 1, and a control system. It is a figure which illustrates typically the substrate conveyance method concerning an embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wafer cassette 20 1st pre-aligner 21 Lamp 22 Wafer support part 23 Sensor 25 Wafer transfer robot arm 27 Load lock chamber 29 Gate valve 33 Wafer vacuum load chamber 35 Wafer transfer vacuum robot arm 39 Gate valve 41 Pre-aligner chamber 43 2nd Pre-aligner 45 Gate valve 100 Electron beam exposure apparatus 101 Optical barrel 103 Electron gun 104 Condenser lens 105 Electron beam deflector 106 Wafer chamber 110 Chuck 111 Mask stage 112 Drive device 113 Laser interferometer 114 Driver 115 Control device 116 Mount body 124 Projection lens 125 Deflector 130 Chuck 131 Wafer Stage 132 Drive Device 133 Laser Interferometer 134 Driver

Claims (6)

A substrate transport device that includes a temperature raising means for raising the temperature of each substrate, and supplies the substrate to an exposure device that forms a pattern under vacuum,
When the temperature raising means is operated after an interval equal to or longer than a predetermined operation interval, the operation of the temperature raising means is started before the substrate is received. 2. The substrate transfer apparatus according to claim 1, wherein the temperature of the substrate is raised in the atmosphere before entering the vacuum chamber. 3. The substrate transfer apparatus according to claim 1, wherein the temperature raising means is a lamp. 4. The substrate transfer apparatus according to claim 1, wherein the temperature raising means raises the temperature of the substrate by a temperature substantially equal to a decrease in the temperature of the substrate due to adiabatic cooling under vacuum. An exposure apparatus for transferring a pattern on a reticle substrate (including a mask substrate) onto a wafer substrate using energy rays under vacuum,
An exposure apparatus comprising the substrate transfer apparatus according to claim 1. A substrate transport method comprising a temperature raising means for raising the temperature of each substrate, and supplying the substrate to an exposure apparatus that forms a pattern under vacuum,
When the temperature raising means is operated after an interval equal to or longer than a predetermined operation interval, the operation of the temperature raising means is started before the substrate is received.