JP2005026634A - Aligner and manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure exposure having an original refractive index of liquid by suppressing the occurrence of the turbulence of the liquid due to the movement of a stage in a liquid-immersion type aligner. <P>SOLUTION: In an aligner performing exposure in such a state that liquid E is interposed between an optical outgoing end in a lens L and a wafer W that is an object for exposure, there are provided a stage 10 mounting the wafer W and performing relative movement to the lens L in performing exposure, a tank 11 for dipping the entire wafer W mounted on the stage 10 in the liquid E, liquid ejection nozzles N1 and N2 ejecting the liquid E same as the liquid E for generating the flow of the liquid E located between the wafer W on the stage 10 and the optical outgoing end in the lens L, and a control means controlling the ejection of the liquid E from the liquid ejection nozzles N1 and N2 at a speed corresponding to the travel speed of the stage 10 along the traveling direction of the stage 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid immersion type exposure apparatus that performs exposure while moving a stage in a state where the entire surface of a substrate is immersed in a liquid, and a method for manufacturing a semiconductor device.

  Currently, the light source for photolithography has shifted from KrF, and ArF technology has become the mainstream. Under these circumstances, device patterns are highly integrated in recent years, and the required specifications are approaching the limits of optical lithography. In addition, F2 lithography technology is being developed as the next generation lithography. However, F2 lithography has the problem of enormous costs because it is premised on the replacement of existing facilities.

  Therefore, Immersion Lithography technology using ArF is considered. Immersion Lithography uses a liquid (typically pure water) between the lens and the substrate to be exposed (for example, a wafer) to make use of the refractive index of the liquid and enable high NA. Is the method. This is expected to enable the same fine technology as F2 with current light sources. In other words, it has the ability to consolidate next-generation technologies within the range of remodeling existing facilities (see, for example, Patent Document 1).

International Publication No. 99/49504 Pamphlet

  However, the immersion technique of Immersion Lithography requires control over the liquid. That is, even if it is a liquid, there are problems such as temperature, viscosity, turbulence, etc., so it is considered that detailed control is necessary for all of them. Unless this liquid is controlled, the original refractive index of the liquid cannot be obtained, and it is impossible to achieve a high NA.

  The present invention has been made to solve such problems. That is, according to the present invention, in an exposure apparatus that performs exposure in a state where a liquid is interposed between a light emitting end of an optical lens unit and a substrate to be exposed, the substrate is placed and optically exposed when performing exposure. A stage that moves relative to the lens unit, a tank for immersing the entire substrate placed on the stage with a liquid, and the substrate on the stage and the light exit end of the optical lens unit A nozzle for ejecting the same liquid as the liquid to generate a liquid flow, and a control means for controlling the ejection of the liquid from the nozzle at a speed corresponding to the moving speed of the stage along the moving direction of the stage. .

  The present invention also includes a step of performing exposure by emitting light from an optical lens unit disposed on the substrate while moving the stage while the entire surface of the substrate placed on the stage is immersed in a liquid. In the manufacturing method of the apparatus, when performing exposure while moving the stage, the flow of the liquid on the substrate is generated at a speed corresponding to the moving speed of the stage.

  In the present invention, when exposure is performed while moving the stage while the entire substrate is immersed in the liquid, the liquid is ejected from the nozzle along the moving direction of the stage and at a speed corresponding to the moving speed of the stage. Therefore, the liquid on the substrate moves with the movement of the stage, and the turbulent flow of liquid due to the movement of the stage can be suppressed.

  In the present invention, even when exposure is performed while moving the stage in a state where the entire substrate is immersed in the liquid, the turbulent flow of the liquid on the substrate due to the movement of the stage can be suppressed, so that the refractive index of the liquid is utilized to the maximum. High-precision exposure can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are schematic views for explaining an exposure apparatus according to the present embodiment. FIG. 1 shows a wafer mounting state, and FIG. 2 shows a liquid injection state. That is, this exposure apparatus is a so-called immersion type exposure apparatus that performs exposure in a state where the entire wafer W, which is a substrate to be exposed, is immersed in a liquid (for example, pure water) E. Therefore, the wafer W and the stage 10 for mounting the wafer W are disposed in the tank 11 for storing the liquid E. The light exit end (tip) of the lens L, which is an optical system, is also configured to be immersed in the liquid E.

  The tank 11 is provided with a water injection port for injecting the liquid E and a drain port for discharging the liquid E so that a certain amount or more of the liquid E does not accumulate in the tank 11. A drain (not shown) for discharging all the liquid E in the tank 11 is also provided.

  The exposure apparatus according to the present embodiment is a scanner type that performs exposure while moving the stage 10 on which the wafer W is placed in such a liquid immersion type. That is, exposure is performed while moving the stage 10 in a predetermined direction with the liquid E interposed between the wafer W and the tip of the lens L.

  In such an exposure apparatus, in this embodiment, liquid ejection nozzles N1 and N2 are arranged around the lens L. The liquid ejection nozzles N1 and N2 are capable of ejecting the same liquid E as the liquid E in the tank 11, and are arranged in a state where openings for ejecting the liquid E through the lens L are opposed to each other.

  The liquid ejection nozzles N1 and N2 eject liquid E along the direction of movement of the stage 10 during exposure and at a speed corresponding to the movement speed of the stage 10 (almost equal speed). A flow corresponding to the movement of the stage 10 can be generated in the liquid E interposed between the front end of the lens L.

  Each liquid ejection nozzle N1, N2 is provided with a control unit (not shown) for controlling the flow rate of the ejected liquid E. The control unit may be used independently or independently by switching the liquid ejection nozzles N1 and N2. The liquid ejection amount of each of the liquid ejection nozzles N1 and N2 is detected by a sensor and accurately controlled.

  Here, the ejection amount control of the liquid E from the liquid ejection nozzles N1 and N2 by the control unit is performed based on the following formula, for example.

VE = D ・ v ・ d
(VE is the ejection amount (m ³ / s) of the liquid E, D is the diameter (m) at the tip of the lens L, v is the moving speed (m / s) of the stage 10, and d is the tip of the lens L and the wafer W. The distance (m) from the surface.)

  The two liquid ejection nozzles N1 and N2 are provided because the stage 10 reciprocates. When the stage 10 moves to one side, the liquid E $ is ejected from only the liquid ejection nozzle N1 and moves to the other side. In this case, the liquid E is ejected only from the liquid ejection nozzle N2.

  By the ejection of the liquid E corresponding to the stage movement from the liquid ejection nozzles N1 and N2, the flow of the liquid E interposed between the wafer W and the lens L and the moving speed of the stage 10 can be made almost equal. It is possible to eliminate the relative speed difference between the movement of the liquid 10 and the movement of the liquid E, and to suppress the turbulent flow of the liquid E generated between them.

  Next, an exposure method using this exposure apparatus will be described. First, as shown in FIG. 1, the wafer W is placed on the stage 10 and vacuum-sucked. Then, alignment with a mask (not shown) is performed.

  Next, the temperature-controlled liquid E (in this case, pure water; in other cases, alcohol, oil, etc.) is injected from the water injection port so that the tip of the lens L is immersed. When the liquid E reaches a certain level or higher, it is automatically discharged from the drain outlet.

  Subsequently, the exposure operation is started. With the start of the exposure operation, the same liquid E as the liquid E placed in the tank 11 is ejected toward the exposure region from the liquid ejection nozzle N1 or the liquid ejection nozzle N2 near the lens L. The flow velocity at that time is the same as the moving speed of the stage 10.

  Here, as shown in FIG. 3, when the stage 10 moves to one side (see arrow x1 in the figure) during exposure, the liquid E is ejected from the liquid ejection nozzle N1 along the same direction. At this time, the liquid E is prevented from being ejected from the liquid ejection nozzle N2.

  On the other hand, as shown in FIG. 4, when the stage 10 moves in the opposite direction (see arrow x2 in the figure), the liquid E is ejected from the liquid ejection nozzle N2 along the same direction. At this time, the liquid E is prevented from being ejected from the liquid ejection nozzle N1.

  In this manner, the liquid E is ejected from the liquid ejection nozzles N1 and N2 in accordance with the direction and speed of the reciprocating movement of the stage 10, so that the liquid E and the stage 10 are relatively moved between the lens L and the wafer W. The speed can be eliminated, and the occurrence of turbulent flow of the liquid E can be minimized.

  FIG. 5 is a schematic perspective view illustrating the relationship between the liquid ejection nozzle and the exposure region. The opening width D1 of the liquid ejection nozzles N1 and N2 is wider than the width of the exposure region S in the lens region. Thereby, the liquid can be ejected from the liquid ejection nozzles N1 and N2 over the entire exposure area S, and liquid turbulence in the exposure area S can be reliably suppressed.

  FIG. 6 is a schematic top view illustrating the positional relationship between the two liquid ejection nozzles and the exposure region. The liquid ejection nozzles N1 and N2 are arranged to face each other along the moving direction of the stage with the lens region interposed therebetween.

  Thus, when the stage moves in the direction of the arrow x1 in the figure, the liquid is ejected from the liquid ejection nozzle N1 in the direction of the arrow x1 'in the figure along the moving direction of the stage. On the other hand, when the stage moves in the direction of the arrow x2 in the opposite figure, the liquid is ejected from the liquid ejection nozzle N2 in the direction of the arrow x2 'in the figure along the moving direction of the stage. Even if the stage is reciprocated, liquid can be ejected from the liquid ejection nozzles N1 and N2 along the direction of movement of the stage, and the turbulent liquid flow can be suppressed in the entire exposure region S. become.

  In the above-described embodiment, an example in which two liquid ejection nozzles are provided has been described. However, the present invention is not limited to this, and a single liquid ejection nozzle is also possible. In other words, a liquid ejection nozzle may be provided in accordance with the stage moving direction during exposure to control the liquid flow.

  The above-described exposure apparatus and exposure method are mainly applied as one step of a semiconductor device manufacturing method. For example, even with exposure using ArF as a light source, a fine technology equivalent to that of an F2 light source is possible. It can be used as a technique for forming a fine pattern in an apparatus.

It is a schematic diagram (wafer mounting state) explaining the exposure apparatus which concerns on this embodiment. It is a schematic diagram (liquid injection state) explaining the exposure apparatus which concerns on this embodiment. It is a schematic diagram (the 1) explaining the exposure method. It is a schematic diagram (the 2) explaining the exposure method. It is a model perspective view explaining the relationship between a liquid ejection nozzle and an exposure area | region. It is a schematic top view explaining the positional relationship between two liquid ejection nozzles and an exposure area.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Stage, 11 ... Tank, L ... Lens, N1 ... Liquid ejection nozzle, N2 ... Liquid ejection nozzle, S ... Exposure area, W ... Wafer

Claims (5)

In an exposure apparatus that performs exposure in a state where a liquid is interposed between a light emitting end in an optical lens unit and a substrate to be exposed,
A stage for placing the substrate and performing relative movement with the optical lens unit when performing exposure;
A bath for immersing the entire substrate placed on the stage with the liquid;
A nozzle that ejects the same liquid as the liquid to generate a liquid flow between the substrate on the stage and a light exit end of the optical lens unit;
An exposure apparatus comprising: control means for performing control for ejecting the liquid from the nozzle at a speed corresponding to the moving speed of the stage along the moving direction of the stage. The nozzle includes two nozzles, a first nozzle and a second nozzle, and the first nozzle and the second nozzle are arranged to face each other so as to eject the liquid in response to the reciprocation of the stage. The exposure apparatus according to claim 1, wherein: The exposure apparatus according to claim 1, wherein a width of the opening of the nozzle from which the liquid is ejected is wider than a width of an exposure area that is performed while moving the stage. A method of manufacturing a semiconductor device, comprising: exposing a light from an optical lens unit disposed on the substrate while moving the stage while the entire surface of the substrate placed on the stage is immersed in a liquid In
A step of generating a liquid flow on the substrate along the moving direction of the stage and at a speed corresponding to the moving speed of the stage when performing exposure while moving the stage. Device manufacturing method. 5. The method of manufacturing a semiconductor device according to claim 4, wherein when the stage reciprocates, the liquid flow on the substrate is reversed in accordance with the moving direction of the stage.

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