JP2007109740A - Exposure device and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide exposure technology for preventing occurrence of air bubbles and the like in immersion liquid at the time of scanning movement. <P>SOLUTION: An exposure device has a projection optical system, and exposes a substrate in a state where a gap between the projection optical system and the substrate is filled with liquid through an original plate and the projection optical system while the original plate and the substrate are relatively moved. The device is provided with a supply means supplying liquid to the gap, a collection means collecting liquid from the gap, a substrate stage holding and moving the substrate, and a substrate stage driving means for moving the substrate stage holding the substrate in one direction for a plurality of regions to be exposed on the substrate, which are arranged in one direction. Every other region to be exposed is exposed while supply of liquid by the supply means, collection of liquid by the collection means, and movement of the substrate stage in one direction by the substrate stage driving means, are performed in parallel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an immersion exposure technique for exposing an original pattern to a substrate in a state where a space on the substrate is filled with a liquid.

  FIG. 10 is a schematic configuration diagram of a general immersion exposure apparatus, and FIGS. 11 to 13 are explanatory diagrams of operations by the general immersion exposure apparatus.

  10 and 11, reference numeral 101 denotes an illumination system unit which has a function of shaping and irradiating an exposure light source and exposure light to a reticle. Reference numeral 102 denotes a reticle stage on which a reticle as an exposure pattern master is mounted, and scans the reticle relative to the wafer at a predetermined reduced exposure magnification ratio. Reference numeral 103 denotes a reduction projection lens, which reduces and projects the original pattern onto the wafer. An exposure apparatus body 104 supports the reticle stage 102 and the projection lens 103. Reference numeral 105 denotes an exposure stage that sequentially and continuously moves the substrate (wafer) for each exposure. A slider 105B moves the wafer to a predetermined position and positions it. A wafer chuck 105C has a shape that holds and fixes the wafer while supporting and fixing the wafer. Reference numeral 106 denotes an alignment scope, which is a microscope that measures an alignment mark on a wafer and an alignment reference mark on a stage, and performs measurement when performing in-wafer alignment and alignment between a reticle and a wafer. Reference numeral 107 denotes a focus scope that performs focus measurement on the wafer surface shape and the optical axis direction. A wafer transfer robot 108 supplies and recovers the wafer. An immersion liquid tank 109 stores the immersion liquid 112, and supplies or recovers the immersion liquid to the wafer 113 via the immersion liquid supply nozzle 110 and the immersion liquid recovery nozzle 111. The wafer 113 is coated with a resist on the surface of a single crystal silicon substrate in order to project and transfer a reticle pattern drawn on the reticle through a reduction exposure system. Reference numeral 114 denotes exposure light that passes through the exposure pattern drawn on the reticle 102 </ b> A with respect to the wafer 113 and is subjected to reduction projection exposure via the reduction projection lens 103.

  Next, the scanning exposure operation by the exposure apparatus will be described with reference to FIG.

As shown in FIG. 12 (1), the original information on the reticle 102 A is transferred and exposed onto the wafer 113 by scanning the exposure surface of the wafer 113 with respect to the slit-shaped exposure area that is the exposure light 114. Here, the arrow indicates the moving direction of the slit exposure area, that is, the scanning moving direction. In the figure, when moving in the horizontal direction, a vertical step movement is performed after the scan movement, and then, as shown in FIG. 12 (2), the scan movement is performed in the direction opposite to the scan direction of the adjacent shot. In general, scanning exposure is continuously performed.
JP-A-6-124873 International Publication No. 99/049504 Pamphlet JP-A-10-303114

  FIG. 13 shows an exposure method when performing immersion exposure by the scanning operation.

  FIG. 13A shows a case where the flow direction of the immersion liquid and the movement direction of the wafer are the same, and the movement direction of the wafer 113 and the flow direction of the immersion liquid are indicated by arrows, and 114 is the immersion liquid. 112 shows exposure light that passes through 112 and is projected onto the wafer 113.

  In the exposure in this state, since the movement of the wafer surface and the flow direction of the immersion liquid 112 are the same direction, there is little turbulence in the flow from the viscous flow due to the relative speed difference generated at the boundary, As a result, exposure can be performed while suppressing generation of bubbles or the like in the immersion liquid 112.

  On the other hand, FIG. 13 (2) shows a case where the flow direction of the immersion liquid and the movement direction of the wafer are opposite to each other. The movement direction of the wafer 113 and the flow direction of the immersion liquid are indicated by arrows. The exposure light that passes through the immersion liquid 112 and is projected onto the wafer 113 is shown.

  In the exposure in this state, since the movement of the wafer surface and the flow direction of the immersion liquid are opposite to those in FIG. 13A, the enlarged view of FIG. In addition, turbulent flow increases due to the generation of viscous flow in opposite directions due to the relative speed difference generated at the boundary. As a result, bubbles (microbubbles) 112A, liquid jump 112B, etc. are generated in the outer peripheral portion of the immersion liquid 112, scan synchronization accuracy deteriorates due to the disturbance of bubbles in the liquid, and stable refractive index and transmittance There was a problem that exposure could not be performed.

  An object of the present invention is to provide an exposure technique that prevents the occurrence of bubbles and the like in the immersion liquid described above and improves the deterioration of scan synchronization accuracy due to the viscous flow of the immersion liquid.

  In order to achieve the above object, an exposure apparatus of the present invention includes a projection optical system, and moves the original and the substrate through the original and the projection optical system while relatively moving the original and the substrate. In an exposure apparatus that exposes the substrate in a state where the gap with the substrate is filled with liquid, supply means for supplying the liquid to the gap, recovery means for collecting the liquid from the gap, and the substrate A substrate stage that holds and moves, and a substrate stage driving unit that moves the substrate stage holding the substrate in the one direction over a plurality of exposed regions on the substrate arranged in one direction, While performing the supply of the liquid, the recovery of the liquid by the recovery means, and the movement of the substrate stage in one direction by the substrate stage driving means, the plurality of exposures Exposing the region to every other.

  In addition, the exposure method of the present invention provides the substrate with the liquid filled in the gap between the projection optical system and the substrate through the original and the projection optical system while relatively moving the original and the substrate. In the exposure method for exposing the substrate, the substrate includes a supply step for supplying the liquid to the gap, a recovery step for collecting the liquid from the gap, and a plurality of exposed regions on the substrate aligned in one direction. Moving the substrate stage holding the substrate in the one direction, and performing the supply step, the recovery step, and the movement step in parallel while exposing the plurality of exposed regions every other one. To do.

  The device manufacturing method of the present invention manufactures a semiconductor device using the exposure apparatus.

  According to the present invention, since every other exposed area is exposed while performing the supply and recovery of the immersion liquid and the movement of the substrate in parallel, the generation of bubbles or the like in the immersion liquid is generated. And immersion exposure can be performed with stable accuracy.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  The embodiment described below is an example as means for realizing the present invention, and should be appropriately modified or changed according to the configuration of the apparatus to which the present invention is applied and various conditions.

  Further, the present invention supplies a storage medium (or recording medium) storing software program codes for realizing an immersion exposure method, a device manufacturing method, and the like, which will be described later, to the system or apparatus. Needless to say, this is also achieved when the computer (or CPU or MPU) of the apparatus reads and executes the program code stored in the storage medium.

  FIG. 1 is a schematic block diagram of an immersion exposure apparatus according to an embodiment of the present invention. FIG. 2 to FIG. 7 are diagrams for explaining the operation of the immersion exposure apparatus of this embodiment.

  1 to 7, reference numeral 1 denotes an illumination system unit which has a function of shaping and irradiating an exposure light source and exposure light to a reticle. Reference numeral 2 denotes a reticle stage on which a reticle as an exposure pattern master is mounted, and a reticle scan operation is performed on the wafer at a predetermined reduced exposure magnification ratio. Reference numeral 3 denotes a reduction projection lens, which reduces and projects an exposure pattern on a reticle (original) onto a wafer (substrate). An exposure apparatus main body 4 supports the reticle stage 2 and the reduction projection lens 3. Reference numeral 5 denotes an exposure stage (substrate stage) that sequentially and continuously moves the substrate (wafer) for each exposure. A slider 5B moves the wafer to a predetermined position and positions it. A wafer chuck 5C has a shape for supporting and fixing the wafer and holding the immersion liquid at the same time. Reference numeral 6 denotes an alignment scope, which is a microscope that measures an alignment mark on a wafer and an alignment reference mark on a stage, and performs measurement when performing in-wafer alignment and alignment between a reticle and a wafer. Reference numeral 7 denotes a focus scope for measuring the wafer surface shape and the optical axis direction focus. Reference numeral 8 denotes a wafer transfer robot for supplying and collecting wafers. An immersion liquid tank 9 stores ultrapure water used as the immersion liquid 12, and the immersion liquid 12 is reduced and projected onto the exposure surface of the wafer 13 by the immersion liquid supply nozzle 10 and the immersion liquid recovery nozzle 11. While supplying the immersion liquid to the exposure light transmitting space between the lower surface of the lens and collecting the immersion liquid from the space, the immersion liquid is caused to flow into the space to form an immersion layer. The wafer 13 is coated with a resist on the surface of the single crystal silicon substrate in order to project and transfer the exposure pattern drawn on the reticle through the reduction projection lens 3 which is a projection optical system. Reference numeral 14 denotes exposure light that passes through the exposure pattern drawn on the reticle 2A, and is reduced and projected onto the exposure surface of the wafer 13 through the reduction projection lens 3 and exposed.

  Next, the operation at the time of scan exposure by the immersion exposure apparatus of the present embodiment will be described with reference to FIGS.

  FIGS. 3 (1) to 3 (3) show basic scanning operations, in which scanning is performed in one direction and one-shot exposure is performed at intervals of one shot (white frame + arrow), and return in the opposite direction is performed. In the exposure (shaded frame + arrow), the operation is performed by exposing a portion extracted as non-exposure with one jump.

  FIG. 4 shows a scanning exposure operation, and the original information of the reticle 2A is transferred and exposed onto the wafer 13 by scanning and moving the exposure surface of the wafer 13 in the slit-shaped exposure area that is the exposure light 14. Here, an arrow indicated by a thick line indicates a moving direction of the slit-shaped exposure area, that is, a scanning moving direction.

  In FIG. 4A, as the reticle 2A moves, one exposure shot 13A is exposed on the exposure surface of the wafer 13 in a jump.

  Next, as shown in FIG. 4 (2), while the reticle stage 2 moves back to the original position, the exposure stage 5 continues to move in the same direction as in FIG. Move to exposure.

  Next, as shown in FIG. 4 (3), the reticle stage 2 moves to the scanning operation from the state where the reticle stage 2 returns to the original position shown in FIG. 4 (1).

  By repeating the above operation, one-step scanning exposure is realized.

  An exposure method for performing immersion exposure by the scan movement will be described with reference to FIGS.

  FIG. 5A shows a case where the flow direction of the immersion liquid is the same as the movement direction of the wafer, and the movement direction of the wafer 13 and the flow direction of the immersion liquid are indicated by arrows. Reference numeral 14 denotes exposure light that passes through the immersion liquid 12 and is projected onto the wafer 13.

  As the wafer 13 scans and moves in the same direction as the flow direction of the immersion liquid 12, a laminar flow of the liquid flow is stabilized to prevent generation of bubbles and the like, and stable exposure is performed.

  FIG. 5B shows a skip operation at the time of non-exposure. The exposure light 14 is not irradiated and the wafer 13 moves in the scanning direction while being in the non-exposure state, and skip-moves to the start position of the next exposure area.

  FIG. 5 (3) shows the next exposure operation, in which the exposure light 14 is again irradiated onto the wafer 13 to perform scan exposure. By repeating this operation, one-shot exposure is continuously performed.

  Note that scan movement is performed by changing at least one of acceleration / deceleration, moving speed, and profile at the time of one skip exposure and at the time of one skip non-exposure skip operation.

  In the exposure shown in FIG. 5, since the movement of the wafer surface and the flow direction of the immersion liquid 12 are the same direction, there is little disturbance of the flow from the viscous flow due to the relative speed difference generated at the boundary portion. As described above, exposure can be performed while suppressing generation of bubbles or the like in the immersion liquid 12.

  6 and FIG. 7 show the return one jump scan operation after the one jump scan exposure shown in FIG.

  As shown in FIGS. 3 (1) to (3), one exposure is performed by scanning movement in one direction (white frame + arrow), and one exposure is skipped by returning exposure (shaded frame + arrow). As a return exposure operation, the extracted part is exposed. Here, this return exposure operation will be described with reference to FIGS.

  In FIG. 6A, at the time of return exposure, the original of the reticle 2A is scanned by moving the exposure surface of the wafer 13 in the direction of the arrow opposite to the direction of the slit-shaped exposure area that is the exposure light 14. Information is transferred and exposed on the wafer 13. Here, the arrow indicates the moving direction of the slit, that is, the scanning operation direction. As the reticle 2A moves, the exposure shot 13A on the exposure surface of the wafer 13 is exposed one by one.

  Next, as shown in FIG. 6 (2), the exposure stage 5 continues to move in the same direction as in FIG. 6 (1) while the reticle stage 2 moves back to the original position in the direction of the arrow. Prepare for the next shot exposure.

  Next, as shown in FIG. 6 (3), the reticle stage 2 moves to the scanning operation from the state where the reticle stage 2 returns to the original position shown in FIG. 6 (1).

  By repeating the above operation, one-shot scanning exposure is realized.

  Next, an exposure method using the return scan exposure of FIG. 6 will be described with reference to FIG.

  FIG. 7A shows a case where the flow direction of the immersion liquid in the return scanning direction opposite to the going direction is the same as the movement direction of the wafer, and the movement direction of the wafer 13 and the flow direction of the immersion liquid are indicated by arrows. Is shown. Reference numeral 14 denotes exposure light that passes through the immersion liquid 12 and is projected onto the wafer 13.

  By making the return scanning movement direction and the immersion liquid flow direction the same (that is, by making the immersion liquid flow in the opposite direction), the flow of the immersion liquid 12 and the scanning movement are synchronized, The laminar flow of the flow is stabilized, the generation of bubbles and the like is prevented, and stable exposure is performed.

  Next, FIG. 7B shows a skip operation at the time of non-exposure, in which the exposure light 14 is not irradiated and the wafer 13 moves in the scan direction while being not exposed, and skips to the start position of the next exposure area. Moving.

  Next, FIG. 7 (3) shows the next exposure operation, in which the wafer 13 is again irradiated with exposure light to perform scan exposure. By repeating such an operation, one-shot exposure is continuously performed.

Also during the return scan exposure, the movement of the wafer surface and the flow direction of the immersion liquid 12 are the same direction, so there is less disturbance of the flow from the viscous flow due to the relative speed difference generated at the boundary, resulting in 12, The exposure can be performed while suppressing the generation of bubbles and the like in the immersion liquid.
[Device manufacturing method]
Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described.

  FIG. 8 shows the flow of manufacturing a microdevice (semiconductor chip such as IC or LSI, liquid crystal panel, CCD, thin film magnetic head, micromachine, etc.). In step S1 (circuit design), a semiconductor device circuit is designed. In step S2 (exposure control data creation), exposure control data for the exposure apparatus is created based on the designed circuit pattern. On the other hand, in step S3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step S4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the wafer and the exposure apparatus to which the prepared exposure control data is input. The next step S5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer produced in step S4. including. In step S6 (inspection), the semiconductor device manufactured in step S5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step S7).

  FIG. 9 shows a detailed flow of the wafer process. In step S11 (oxidation), the wafer surface is oxidized. In step S12 (CVD), an insulating film is formed on the wafer surface. In step S13 (electrode formation), an electrode is formed on the wafer by vapor deposition. In step S14 (ion implantation), ions are implanted into the wafer. In step S15 (resist process), a photosensitive agent is applied to the wafer. In step S16 (exposure), the circuit pattern is printed on the wafer by exposure using the exposure apparatus described above. In step S17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step S19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

1 is a schematic configuration diagram of an immersion exposure apparatus according to an embodiment of the present invention. It is operation | movement explanatory drawing by the immersion exposure apparatus of this embodiment. It is operation | movement explanatory drawing by the immersion exposure apparatus of this embodiment. It is operation | movement explanatory drawing by the immersion exposure apparatus of this embodiment. It is operation | movement explanatory drawing by the immersion exposure apparatus of this embodiment. It is operation | movement explanatory drawing by the immersion exposure apparatus of this embodiment. It is operation | movement explanatory drawing by the immersion exposure apparatus of this embodiment. It is a figure explaining the manufacturing flow of a microdevice. It is a figure explaining a wafer process. It is a schematic block diagram of a general liquid immersion exposure apparatus. It is operation | movement explanatory drawing by a general liquid immersion exposure apparatus. It is operation | movement explanatory drawing by a general liquid immersion exposure apparatus. It is operation | movement explanatory drawing by a general liquid immersion exposure apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illumination system unit 2 Reticle stage 2A Reticle 3 Reduction projection lens 4 Exposure apparatus main body 5 Exposure stage 5B Slider 5C Wafer chuck 6 Alignment scope 7 Focus scope 8 Wafer transfer robot 9 Immersion liquid tank 10 Immersion liquid supply nozzle 11 Immersion liquid Recovery nozzle 12 Immersion liquid 13 Wafer 13A Exposure shot 14 Exposure light

Claims (11)

The projection optical system is provided, and the substrate is moved through the original and the projection optical system and the gap between the projection optical system and the substrate is filled with a liquid while relatively moving the original and the substrate. In an exposure apparatus that performs exposure,
Supply means for supplying the liquid to the gap;
Recovery means for recovering the liquid from the gap;
A substrate stage for holding and moving the substrate;
A substrate stage driving means for moving the substrate stage holding the substrate in the one direction over a plurality of exposed areas on the substrate arranged in one direction;
While the supply of the liquid by the supply means, the recovery of the liquid by the recovery means, and the movement of the substrate stage in the one direction by the substrate stage driving means are performed in parallel, every other plurality of exposed areas are arranged. An exposure apparatus characterized in that exposure is performed.   The exposure apparatus according to claim 1, wherein an exposure area that is not exposed during the movement of the substrate stage in the one direction is exposed while the substrate stage is moved in a direction opposite to the one direction.   The exposure apparatus according to claim 1, wherein the substrate stage is moved at different speeds during exposure of the substrate and during non-exposure of the substrate. An original stage for holding and moving the original plate, and an original stage driving means for moving the original stage;
The original stage driving means moves the original stage in a direction opposite to that during the exposure of the substrate during the movement of the substrate stage in the one direction by the substrate stage driving means and during the non-exposure of the substrate. The exposure apparatus according to claim 1, wherein the exposure apparatus is characterized.   5. The flow rate control of the substrate stage according to the flow rate of the liquid, or the flow rate control of the liquid according to the transfer rate of the substrate stage is performed. 6. The exposure apparatus described in 1. In the exposure method of exposing the substrate through the original and the projection optical system and in the state where the gap between the projection optical system and the substrate is filled with a liquid while relatively moving the original and the substrate,
Supplying the liquid to the gap;
A recovery step of recovering the liquid from the gap;
Moving the substrate stage holding the substrate in the one direction over a plurality of exposed regions on the substrate aligned in one direction,
An exposure method comprising exposing every other plurality of exposed areas while performing the supplying step, the collecting step, and the moving step in parallel.   The exposure method according to claim 6, wherein an exposed area that is not exposed during the movement of the substrate stage in the one direction is exposed while the substrate stage is moved in a direction opposite to the one direction.   The exposure method according to claim 6, wherein the substrate stage is moved at different speeds during exposure of the substrate and during non-exposure of the substrate.   7. The original stage that holds and moves the original plate is moved in a direction opposite to that during the exposure of the substrate during movement of the substrate stage in the one direction and non-exposure of the substrate. 9. The exposure method according to any one of 8 above.   The flow rate control of the substrate stage according to the flow rate of the liquid, or the flow rate control of the liquid according to the transfer rate of the substrate stage is performed. An exposure method according to 1.   A device manufacturing method comprising a step of exposing a substrate using the exposure apparatus according to claim 1.

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