TWI478205B - Discharge lamp - Google Patents

Description

Discharge lamp

The present invention relates to a discharge lamp, a connection cable used when the discharge lamp is connected to the light source, a light source device including the discharge lamp, and an exposure device including the light source device.

In the lithography step for manufacturing various components (micro devices, electronic components, etc.), in order to transfer a pattern formed on a reticle (or a photo mask, etc.) to a coating On a wafer (or a glass plate) having a photoresist, a projection exposure device such as a stepper (such as a still exposure type) and a scanning exposure type projection exposure device such as a scanning stepper are used for exposure. Device. In these exposure apparatuses, an exposure light source device in which a discharge lamp such as a mercury lamp and a condensing mirror are combined is used, and the discharge lamp is held by a predetermined mounting mechanism.

In the conventional light source device having a discharge lamp, there is a type in which a cooling mechanism is provided in order to reduce the influence of heat generation. One of the conventional cooling mechanisms is a mechanism for supplying air that is cooled by the outer surface of one of the metal ports of the discharge lamp to the outside of the other metal port via the outer surface of the valve portion (see, for example, Patent Document 1). As another example of the conventional cooling mechanism, an annular groove portion is provided in the metal port of the discharge lamp, and a mechanism for supplying the cooled air to the valve portion through the groove portion and the predetermined air supply pipe is also known (for example, Patent Document 2).

(Patent Document 1) Japanese Patent Laid-Open Publication No. Hei 9-213129

(Patent Document 2) Japanese Patent Laid-Open No. Hei 11-283898

In the conventional light source device, the cooling mechanism of the discharge lamp mainly blows cold air to the valve portion of the discharge lamp, so that there is a problem that the cooling effect on the metal port is small.

In addition, when the discharge port has a metal port on the fixed side and a metal port on the free end side, when the metal port on the free end side is cooled by using a conventional cooling mechanism, it is necessary to provide a ventilation pipe or the like around the metal port. There is a problem of shielding a large amount of light from the discharge lamp.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a light-shielding amount for light generated by a discharge lamp when a cooling effect on a metal port of a discharge lamp is large, and when a metal port on a free end side is cooled. Fewer light source devices.

Further, it is an object of the present invention to provide a discharge lamp, a connection cable, and an exposure technique using the light source device as described above, which are applicable to the light source device as described above.

A discharge lamp according to the present invention is a discharge lamp in which a discharge electrode is housed in a glass member, and is characterized in that it includes a metal port member connected to the glass member, and a metal port member is attached to the metal port member and formed of a conductive material. a relay member that is fixed to the relay member and that supplies electric power for discharge to the metal port member through the relay member; is provided in the relay member, and supplies the cooling medium to the a flow path of the metal port member; and a second cable that is fixed to the relay member and that can supply the cooling medium to the metal port member through the flow path.

Further, the connection cable of the present invention is a connection cable for connecting a device for cooling medium and electric power to a supply source and a power source of the cooling medium, and is characterized in that it is formed of a conductive material. And can be detachably attached to the device using the cooling medium and electric power a member; a tubular member having a one end fixed to the relay member and formed of a flexible material, having a flow path of the cooling medium; and being separately provided separately from the tubular member, fixing one end to the relay A member, and a conductive member formed of a conductive material having conductivity.

Further, the light source device of the present invention is a light source device connected to a supply source of a power source and a cooling medium, and includes a glass member including a discharge electrode and a metal port member connected to the glass member. a discharge lamp; and a connection cable according to the present invention, wherein a relay member of the connection cable is attached to a metal port member of the discharge lamp, and a flow path of the cooling medium is formed in the relay member, and the connection is transmitted through the connection. The conductive member of the cable and the relay member are supplied with electric power to the metal port member, and the tubular member passing through the connecting cable and the relay member are supplied to the metal by the supply source. Mouth components.

Further, the exposure apparatus of the present invention is an exposure apparatus for exposing a pattern to a photosensitive substrate by exposure light generated from a light source device, and the light source device of the present invention is used as the light source device.

According to the discharge lamp of the present invention, the electric power for discharge is supplied to the discharge electrode through the electroconductive member, the relay member, and the metal port member of the connection member. Further, the cooling medium is supplied to the metal port member through the flow path provided in the connection member and the relay member.

According to the connection cable of the present invention, the power from the power source is supplied to the device side through the flexible conductive member and the relay member, and the cooling medium from the supply source transmits the flexible tubular member and the medium. It is supplied to the device side following the member.

Therefore, the light source device and the exposure device according to the present invention are derived from electricity The power source of the source is supplied to the discharge electrode through the connection cable and the metal port member. Further, the cooling medium from the supply source is supplied to the metal port member through the tubular member of the connecting cable and the flow path in the relay member. Therefore, the cooling effect on the metal port member is large. Further, the cooling medium passes through the flow path provided in the relay member in the vicinity of the metal port member. Therefore, when the metal port member is located on the free end side, the light-shielding amount of light generated by the discharge lamp by the cooling medium supply pipe or the like is small, the light use efficiency is high, and the temperature of the light source device rises. less.

Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to the first to fifth figures.

The first drawing shows a projection exposure apparatus (exposure apparatus) including the exposure light source 30 of the present embodiment. In the first drawing, the discharge lamp 1 composed of an arc discharge type mercury lamp is fixed to the insulator by the mounting member 31. The fixed plate 29 is constructed. Further, the electrodes on the anode side and the cathode side in the discharge lamp 1 are supplied with electric power by the power source 32 through the flexible power cables 33D and 33B, respectively. In addition, air (hereinafter referred to as cold air) that is cooled by the air filter 34 is supplied to the air outlets 35D and 35B through which the flexible air supply pipes 35D and 35B are supplied. In the air blowing device 34, a mechanism that extracts air obtained by dust removal and cooling from external air (or nitrogen gas taken in from a nitrogen bottle, etc.) can be used with a predetermined air volume. In addition to the air blower 34, a compressed air supply unit that supplies compressed air to a cylinder or the like in a factory may be used. The cold air can be at room temperature and does not necessarily cool to below room temperature.

In addition, the elliptical mirror 2 is enclosed in such a manner as to surround the valve portion of the discharge lamp 1. (Condenser) is fixed to a bracket (not shown). The light-emitting portion in the valve portion of the discharge lamp 1 is disposed in the vicinity of the first focus P1 of the elliptical mirror 2 as an example. The discharge lamp 30, the elliptical mirror 2, the mounting member 31, the power cables 33D and 33B, the air supply pipes 35D and 35B, the power source 32, and the air blowing device 34 are included to constitute the exposure light source 30 (described later in detail).

The light beam emitted from the discharge lamp 1 is converged in the vicinity of the second focus P2 by the elliptical mirror 2, and is incident on the optical path bending mirror 4 by being formed as divergent light in the vicinity of the shutter 3 in the open state. The opening and closing of the shutter 3 is performed by the shutter driving device 3a. For example, the stage control system 15 to be described later controls the shutter driving device 3a in accordance with an instruction from the main control system 14 for collectively operating the entire control device.

The light beam reflected by the mirror 4 is incident on the interference filter 5, and only the predetermined bright line (for example, i line of wavelength 365 nm) of the exposure light IL is selected by the interference filter 5. In addition, as the exposure light IL, in addition to the i line, a g line, an h line, or a mixed light of the above, or a bright line of a lamp other than a mercury lamp or the like may be used. The selected exposure light IL is incident on the fly-eye lens 6 (optical integrator), and a plurality of secondary light sources are formed on the variable aperture stop 7 disposed on the exit surface of the fly-eye lens 6. The exposure light IL passing through the variable aperture stop 7 is incident on a reticle blind (variable field aperture) 9 via a first relay lens 8. The arrangement surface of the reticle blind 9 is substantially conjugate with the pattern surface of the reticle R, and the opening shape of the reticle blind 9 is set by the driving device 9a, thereby defining the illumination area on the reticle R . Further, in order to prevent unnecessary exposure light from being irradiated onto the wafer W during stepping or the like, the stage control system 15 is configured to open and close the reticle blind 9 through the driving device 9a.

The exposure light IL that has passed through the reticle blind 9 passes through the second relay The mirror 10, a dichroic mirror 11 that reflects the exposure light IL, and a condenser lens 12 vertically illuminate the pattern area of the pattern surface of the reticle R. The shutter 3, the mirror 4, the interference filter 5, the fly-eye lens 6, the variable aperture stop 7, the relay lens 8, 10, the reticle blind 9, the dichroic beam splitter 11 and the collecting lens 12 are included to constitute the illumination. Optical system 13. The light beam from the exposure light source 30 illuminates the reticle R (mask) as the exposure light IL via the illumination optical system 13, and transmits the pattern in the pattern region of the reticle R by the projection optical system PL at a projection magnification β (β). For example, 1/4, 1/5, etc.) is exposed on a shot area of the wafer W (photosensitive substrate) to which the photoresist has been applied. Hereinafter, the optical axis AX parallel to the projection optical system PL is set to the Z axis, the plane parallel to the first drawing in the plane perpendicular to the Z axis is set to the X axis, and the plane perpendicular to the first drawing is set to the Y axis. .

At this time, the reticle R is held on the reticle stage RST on the reticle base (not shown) so as to be slightly movable in the X direction, the Y direction, and the rotation direction around the Z axis. The position of the reticle stage RST is measured with high precision by irradiating the laser beam 17R fixed to the stage with the laser beam 13A for measuring the laser beam, and the measured value is supplied to The stage control system 15 and the main control system 14. Based on the measured value and the control information from the main control system 14, the stage control system 15 controls the position of the reticle stage RST through the drive system 19R including a linear motor or the like.

On the other hand, the wafer W is held on the wafer stage WST through a wafer holder not shown, and the wafer stage WST is placed on the wafer base so as to be movable in the X direction and the Y direction. Not shown). The position of the wafer stage WST is high-precision by a laser interference meter 18W that irradiates the measuring laser beam 17W to the moving mirror 17W fixed to the stage. The measurement is supplied to the stage control system 15 and the main control system 14. Based on the measured value and the control information from the main control system 14, the stage control system 15 controls the position of the wafer stage WST (wafer W) through the drive system 19W including a linear motor or the like.

When the wafer W is exposed, the exposure of each exposure region of the wafer W to the exposure field of the projection optical system PL by the wafer stage WST is repeatedly performed in a step and repeat manner. And an operation of irradiating the light beam from the exposure light source 30 to the reticle R through the illumination optical system 13 and exposing the pattern of the reticle R to the exposure region on the wafer W through the projection optical system PL. Thereby, the image of the pattern of the reticle R is transferred to each of the exposed regions on the wafer W.

Wherein, in order to perform calibration in advance during exposure, a reticle calibration system 20 for detecting the position of the alignment mark formed on the reticle R is provided above the reticle R, on the side of the projection optical system PL. A calibration sensor 21 is provided for detecting the position of the calibration mark attached to each shot area on the wafer W. Further, a reference mark member 22 on which a plurality of reference marks for the calibration sensor 21 or the like are formed is provided in the vicinity of the wafer W on the wafer stage WST. The detection signals of the reticle calibration system 20 and the calibration sensor 21 are supplied to the calibration signal processing system 16, and the calibration signal processing system 16 determines the arrangement of the detected marks by, for example, image processing of the detection signals. Coordinates, and the information of the aligned coordinates is supplied to the main control system 14. The main control system 14 performs calibration of the reticle R and the wafer W based on the information of the aligned coordinates.

Next, the basic configuration of the exposure light source 30 in the discharge lamp 1 including the projection exposure apparatus of this embodiment will be described.

2A is a view showing a part of the discharge lamp 1 of the exposure light source 30 of the first drawing and a part of the mounting mechanism thereof. In the second A diagram, the discharge lamp 1 is provided with a valve portion 25a and a glass tube 25 composed of two cylindrical rod-shaped portions 25b and 25c that are substantially symmetrically fixed to sandwich the valve portion 25a, and an end portion of the rod-shaped portion 25b on one of the fixed sides The cathode-side metal port portion 26; and the anode-side metal port portion 28 that is connected to the end portion of the rod-like portion 25c on the free end side whose diameter is gradually smaller toward the other side. The anode EL1 and the cathode EL2 for forming the light-emitting portion in the valve portion 25a are fixed to each other, and the cathode EL2 and the anode EL1 are connected to the metal mouth portions 26 and 28, respectively, and the metal mouth portions 26 and 28 are electrically conducted. Metal products with good rate and thermal conductivity. The metal mouth portion 26, the glass tube 25, and the metal mouth portion 28 are arranged on a straight line passing through the center of the light-emitting portion of the central axis of the rod-shaped portions 25b and 25c of the glass tube 25. The direction parallel to the line connecting the central axes of the rod-like portions 25b and 25c is the longitudinal direction L of the discharge lamp 1.

The metal mouth portions 26 and 28 are basically used as power receiving terminals for supplying electric power to the cathodes EL2 and the anodes EL1 through the power cables 32 through the power cables 33B and 33A (see the first drawing). In addition, the metal mouth portion 26 can also be used as a held portion for holding the glass tube 25 (discharge lamp 1), and the metal mouth portions 26 and 28 each have a heat for circulating the glass tube 25. The mechanism of the gas to be cooled.

That is, the metal mouth portion 26 continuous with the cathode EL2 is sequentially formed by the rod portion 25b on the outer side: a flange portion 26a; a cylindrical shaft portion 26b; a cylindrical recess portion 26f; and an outer diameter slightly smaller than the shaft portion The cylindrical fixing portion 26h of 26b is shaped at the boundary between the concave portion 26f and the fixed portion 26h. A pressed surface 26g composed of a surface substantially perpendicular to the longitudinal direction L is formed.

When the discharge lamp 1 is fixed, the shaft portion 26b of the discharge lamp 1 is fitted to the opening portion 31b of the attachment member 31 which is shown by a two-dot chain line, and the flange portion 26a is placed on the upper surface 31a of the attachment member 31. As shown in FIG. 2B, circular openings 27A and 27B are formed in the flange portion 26a, and cylindrical projections fixed to the upper surface 31a of the second A figure are inserted into the openings 27A and 27B (Fig. This is not shown, whereby the positioning of the discharge lamp 1 in the direction of rotation is performed.

Further, on the outer surface of the shaft portion 26b, a groove portion 26d is formed in a spiral shape around the axis parallel to the longitudinal direction L. In the groove portion 26d, the air blowing device 34 transmits the flexible air blowing pipe 35B and the air blowing path 31c formed in the mounting member 31 to supply cold air. Further, the metal mounting member 31 having good conductivity is fixed to the terminal 38 by the bolt 39, and the terminal 38 is connected to the power source 32 by the power cable 33B. With this configuration, the power source 32 transmits power to the cathode EL2 of the discharge lamp 1 through the power cable 33B, the terminal 38, the mounting member 31, and the flange portion 26a of the metal mouth portion 26.

Further, the elastic members 36A, 36B, and 36C are fixed to the three portions below the mounting member 31 so as to be rotatable downward by the tension coil springs 37A, 37B, and 37C. The pressed surface 26g of the metal mouth portion 26 is biased downward at the front end portions of the biasing members 36A to 36C, whereby the metal mouth portion 26 (and thus the discharge lamp 1) is stably held by the mounting member 31. Further, the biasing members 36A to 36C are pulled upward by a lever mechanism not shown, whereby the discharge lamp 1 can be easily removed by the mounting member 31.

Next, in the second A picture, the anode side of the discharge lamp 1 (in this example) The metal nozzle portion 28 of the free end side is generally formed on the surface of the substantially cylindrical shaft portion 28a, and the groove portion 28b is spirally formed around the axis parallel to the longitudinal direction L. Further, a substantially cylindrical cover member 50 made of a metal having good conductivity (for example, copper, brass, aluminum, etc., the same applies hereinafter) is fixed so as to cover the metal mouth portion 28 from the outside. A flow path bending member 71 made of metal having good conductivity is fixed to the lid member 50.

Fig. 3B is an enlarged cross-sectional view showing the configuration of the vicinity of the metal mouth portion 28 on the anode side of the discharge lamp 1 of Fig. A, the third A diagram is the top view of the third B diagram, and the third C diagram is the third B Side view of the main part of the figure. In the third diagram, the upper end of the shaft portion 28a of the groove portion 28b in which the metal mouth portion 28 is formed is formed with a disk-shaped mounting portion 28c via the annular cutout portion 28d, and the center portion of the mounting portion 28c faces outward. There is a ventilation groove portion 28e.

Further, the cover member 50 has a belt-like flat plate portion 50a placed on the upper surface of the mounting portion 28c, and a cylindrical portion 50c covering the side surface of the metal mouth portion 28, and the front end portion 50ca of the cylindrical portion 50c is a metal mouth portion 28 Further, it extends toward the side of the rod portion 25c of the glass tube 25. However, in the third B diagram, the gap between the shaft portion 28a and the cylindrical portion 50c is depicted as having a gap, but the gap may actually be very small.

The bottom surface of the flat plate portion 71a of the flow path bending member 71 fixed to the lid member 50 is formed with a cylindrical projection 71d so as to protrude from the opening 50b at the center of the flat plate portion 50a of the lid member 50. A cylindrical fitting portion 71b is formed on the upper surface of the flat plate portion 71a. Then, the center portion of the projection 71d of the flow path bending member 71 is formed at a height position substantially in the middle of the fitting portion 71b, and is formed therein to communicate with the opening 71e (see FIG. 3C) on the side surface of the fitting portion 71b. Way to bend The air supply path 71c supplies the cold air for cooling the metal mouth part 28 to the air supply path 71c by the opening 71e. As shown in FIG. 3A, a hole-expanding portion 71f is formed at four portions on the upper surface of the flow path bending member 71, and the flow path bending member 71 is formed by the bolt 53 in the hole expanding portion 71f as shown in FIG. The lid member 50 (with an opening for the bolt 53) is integrally fixed to the metal mouth portion 28.

In the third diagram, the electric power supplied to the flow path bending member 71 through the power cable 33D of the first drawing is transmitted to the anode in the glass tube 25 through the cover member 50 and the metal mouth portion 28. In addition, the cold air supplied to the opening 71e of the flow path bending member 71 through the air supply pipe 35D of the first drawing is supplied to the metal through the air supply path 71c, the opening 50b of the cover member 50, the groove portion 28e, and the notch portion 28d. The groove portion 28b of the mouth portion 28, the air flowing through the groove portion 28b is blown between the rod portion 25c and the front end portion 50ca of the lid member 50 to the valve portion 25a side of the glass tube 25 of the second A drawing. Thereby, the metal mouth portion 28 and the glass tube 25 are effectively cooled.

Next, in the fourth A diagram, a part of the connection cable 72 of the present example including the power cable 33D of the first diagram and the air supply pipe 35D is cut away, and the connection cable 72 is a first connection mechanism 73A and a power cable 33D. The air supply pipe 35D and the second connection mechanism 73B are connected to each other. Further, the fourth B diagram shows a side view of the first link mechanism 73A in the fourth A diagram.

In the fourth A diagram, the first coupling mechanism 73A includes an annular member 74A formed with a through hole 74Aa that is loosely fitted to the fitting portion 71b of the flow path bending member 71 of the third B diagram, and is formed at the front end. A rod member 75A having a screw portion; and a fixing screw 79A. The annular member 74A is a metal product having good electrical conductivity. Taking along the central axis including the through hole 74Aa The slit portion 74Ab is formed so as to traverse the through hole 74Aa, and the through hole and the screw portion 74Ae are formed so as to traverse the slit portion 74Ab (see FIG. 4B). The rod 75A is attached to the annular member 74A so that the screw portion of the distal end is screwed to the screw portion 74Ae through the through hole. With this configuration, as shown in FIG. 4B, the fitting portion 71b of the flow path bending member 71 is fitted into the through hole 74Aa of the annular member 74A, and the slit portion 74Ab is restrained by the rod 75A. Thereby, the annular member 74A can be stably and quickly fixed to the flow path bending member 71.

The upper surface and the bottom surface of the annular member 74A (the surface placed on the flat plate portion 71a of the flow path bending member 71) are processed into a flat surface, and a screw portion is formed in the vicinity of the slit portion 74Ab on the upper surface thereof as shown in FIG. 74Ag. Further, a T-shaped air blowing path 74Ac having a first open end and communicating with the through hole 74Aa is formed at a substantially central position of the annular member 74A, and a screw portion 74Ad is formed at the second open end of the air blowing path 74Ac to supply air. The third open end of the path 74Ac is closed by a set screw 79A. The air supply path required in the annular member 74A is an air supply path that connects the inner through hole 74Aa and the one side of the side surface. However, since the air passage having only two open ends is difficult to process, it is easy to form a T. After the glyph air supply path 74Ac, the unnecessary third open end is blocked by the fixing screw 79A. Thereby, the joint mechanism 73A is easily manufactured.

Further, as shown in FIG. 4B, the height of the air supply path 74Ac that communicates with the through hole 74Aa of the annular member 74A is the distance from the bottom surface of the first open end, and the distance is set at the fitting portion 71b of the flow path bending member 71. The height of the flat plate portion 71a of the opening 71e (communicating with the air supply path 71c of the third B diagram) is the same. In this example, the fitting of the flow path bending member 71 is performed. In a state in which the portion 71b is fitted into the through hole 74Aa of the annular member 74A, the annular member 74A is adjusted with respect to the flow path such that the first open end of the air blowing path 74Ac faces the opening 71e of the flow path bending member 71. The relative rotation angle of the curved member 71. Thereby, the cold air supplied from the screw portion 74Ad side of the air blowing path 74Ac of the annular member 74A is supplied to the metal port portion 28 side of the third B diagram through the air blowing path 71c of the flow path bending member 71.

Further, as shown in FIG. 4A, the screw portion 74Ag formed on the upper surface 74Af of the annular member 74A and the screw portion 74Ad communicating with the air supply path 74Ac are formed by the arrangement of the sandwiching slit portion 74Ab. With this configuration, the power cable 33D and the air supply pipe 35D can be connected to the annular member 74A so as to be substantially parallel to the side surface direction.

In addition, the second connection mechanism 73B is similar to the first connection mechanism 73A, and includes a metal annular member 74B having a good electrical conductivity through the through hole 74Ba, and a rod 75B that is coupled to the slit portion 74Ab; A fixing screw 79B for closing the third open end of the T-shaped air supply passage 74Bc in the annular member 74B.

Further, the power cable 33D of the present example has an elongated and a large number of wires formed into a cylindrical mesh shape and has a flexible member. First and second terminals 77A and 77B each having an opening and having conductivity of a flat plate portion are fixed to both ends of the power cable 33D. In addition, the air supply pipe 35D is made of a soft synthetic resin (for example, soft polyvinyl chloride, low-density polyethylene, etc., or the like) or synthetic rubber, and has a flexible elongated cylindrical member and will be cold-air. Air is supplied to the inside. The first and second air blowing terminals 76A and 76B in which the air blowing path 76Aa or the like is formed in a cylindrical shape are fixed in an airtight state at both ends of the air blowing pipe 35D. The front end portion of the first air blowing terminal 76A is formed with a screw The screw portion 76Ab of the screw portion 74Ad of the annular member 74A is also formed with a screw portion that is screwed to the screw portion of the open end of the air passage 74Bc of the annular member 74B at the distal end portion of the second air blowing terminal 76B.

Next, in a state where the flat plate portion of the first terminal 77A is placed on the upper surface 74Af of the annular member 74A of the first coupling mechanism 73A, the bolt 78A is screwed into the screw portion 74Ag by the opening of the flat plate portion. The first terminal 77A is fixed to the annular member 74A. Similarly, the second terminal 77B is fixed to the annular member 74B by the bolt 78B, and the annular member 74A of the first coupling mechanism 73A and the annular member 74B of the second coupling mechanism 73B are electrically connected to the power cable 33D. Connected in the on state.

Further, the screw portion 76Ab of the first air blowing terminal 76A is coupled to be screwed to the screw portion 74Ad of the annular member 74A, and the screw portion of the second air blowing terminal 76B is screwed to the ring member 74B. The screws are not shown. As a result, the through hole 74Aa of the annular member 74A of the first coupling mechanism 73A and the through hole 74Ba of the annular member 74B of the second coupling mechanism 73B communicate with each other through the air supply pipe 35D.

In the connection cable 72 of the fourth embodiment, the power supplied from the power source 32 of the first diagram to the annular member 74B of the second connection mechanism 73B is transmitted through the power cable 33D and the annular member 74A of the first connection mechanism 73A. It is supplied to the flow path bending member 71 of the third B diagram. Further, the cold air that is supplied to the air blowing path 74Bc in the annular member 74B of the second connecting mechanism 73B of the fourth drawing is transmitted through the air blowing pipe 35D and the first connecting mechanism 73A. The air blowing path 74Ac in the shape member 74A is blown into the air passage 71c of the flow path bending member 71 of the third B diagram.

Here, in the fourth A diagram, the connection mechanisms 73A and 73B are regarded as a part of the connection cable 72, but the flow path bending member 71 of the discharge lamp 1 of the third A diagram may be attached by the connection mechanism 73A. The connection mechanism 73A is regarded as one of the constituent members of the discharge lamp 1.

Further, the second connection mechanism 73B may be omitted from the connection cable 72 of the fourth A diagram. In this case, the second terminal 77B of the power cable 33D may be directly connected to the terminal of the power source 32 of the first diagram, and the second air blowing terminal 76B of the air supply pipe 35D may be directly connected to the air blowing device 34 of the first drawing. Air supply piping.

Next, the fifth diagram shows a state in which the flow path bending member 71 of the discharge lamp 1 of the third drawing B is connected (connected) to the power source 32 and the air blowing device 34 of the first drawing by the connecting cable 72 of the fourth A diagram. In the fifth figure, the power supply 32 is connected to the metal mounting member 40 having good electrical conductivity through the terminal fixed by the bolt 44 and the power cable 46. Further, a metal flow path bending member 47 having a conductivity substantially the same as that of the flow path bending member 71 of the third B diagram is fixed to the attachment member 40 by a bolt (not shown).

The flow path bending member 47 has a flat plate portion 47a fixed to the attachment member 40, and a cylindrical fitting portion 47b protruding outward from the flat plate portion 47a so as to extend from the bottom surface of the flat plate portion 47a to the middle of the fitting portion 47b. After the height position, the air passage 47c is formed to communicate with the opening on the side surface of the fitting portion 47b. The air blowing passage 47c transmits the cold air by the air blowing device 34 through the pipe 45 disposed in the recess 40a of the mounting member 40 and the air supply path.

In the fifth diagram, in order to connect the connecting cable 72 to the flow path bending member 71 of the discharge lamp 1, the through hole 74Aa of the annular member 74A of the first coupling mechanism 73A may be fitted to the flow path bending member 71. Joint 71b, and the rod member 75A of the fourth A drawing is restrained in a state where the first open end of the air blowing path 74Ac of the fourth A diagram is opposed to the opening 71e of the flow path bending member 71 of the third B diagram.

In the same manner, in order to connect the connecting cable 72 to the flow path bending member 47 on the power supply side of the fifth diagram, the through hole 74Ba of the annular member 74B of the second connecting mechanism 73B is fitted to the fitting portion of the flow path bending member 47. 47b, in a state in which the opening that communicates with the first open end of the air supply path 74Bc of the fourth A diagram and the air supply path 47c of the flow path curved member 47 of the fifth figure is opposed to each other, the member of the fourth A diagram is restrained 75B. As described above, by using the connecting cable 72, the power source 32, the air blowing device 34, and the discharge lamp 1 can be connected extremely easily and quickly.

In the fifth diagram, the electric power supplied from the power source 32 to the flow path bending member 47 through the power cable 46 and the attachment member 40 is transmitted through the annular member 74B and the second terminal 77B of the second connection mechanism 73B of the connection cable 72. The power cable 33D, the first terminal 77A, and the annular member 74A of the first coupling mechanism 73A are supplied to the flow path bending member 71 of the discharge lamp 1. The electric power supplied to the flow path bending member 71 is supplied to the anode in the glass tube 25 through the cover member 50 and the metal mouth portion 28.

On the other hand, the cold air supplied to the air supply path 47c in the flow path bending member 47 through the pipe 45 of the fifth drawing through the pipe 45 is indicated by arrows A1, A2, A3, and A4, and passes through the second connecting mechanism. The air supply path 74Bc in the annular member 74B of the 73B, the second air supply terminal 76B, the air supply pipe 35D, the first air supply terminal 76A, and the air supply path 74Ac in the annular member 74A of the first connection mechanism 73A are blown to the air. The air passage 71c in the flow path bending member 71. Then, the cold air supplied to the air supply path 71c passes through the opening 50b of the cover member 50, the groove portion 28e, the notch portion 28d, and the groove of the metal mouth portion 28 as indicated by arrows A5, A6, and A7. The space between the portion 28b and the rod portion 25c and the front end portion of the cylindrical portion 50c of the lid member 50 is blown to the valve portion 25a (see FIG. 2A) side of the glass tube 25. Thereby, the metal mouth portion 28 and the glass tube 25 are effectively cooled.

Further, in the fifth drawing, in order to perform maintenance of the discharge lamp 1, for example, when the connecting cable 72 is separated by the discharge lamp 1, the rod member 75A of the fourth A diagram can be loosened, and the flow path bending member 71 can be embedded. The joint portion 71b removes the annular member 74A of the first joint mechanism 73A. Similarly, in order to separate the connecting cable 72 by the power source 32 and the air blowing device 34 of the fifth diagram, the rod 75B of the fourth A diagram can be loosened, and the second joint can be removed by the fitting portion 47b of the flow path bending member 47. The annular member 74B of the mechanism 73B. By using the connecting cable 72 as described above, the power source 32, the air blowing device 34, and the discharge lamp 1 can be separated extremely easily and quickly.

The effects of the exposure light source 30 and the exposure apparatus of the present embodiment are as follows.

(1) The lamp system in a state in which the first connection mechanism 73A (annular member 74A) of the fourth embodiment A is connected to the flow path bending member 71 of the discharge lamp 1 of the third diagram B is provided with the glass tube 25 a connected metal mouth portion 28; an annular member 74A formed of the conductive material in the metal mouth portion 28 (through the flow path bending member 71); fixed to the annular member 74A and transparent to the annular member 74A The power cable 33D for supplying electric power for discharge to the metal port portion 28, the air member 74A for supplying cold air to the metal port portion 28, and the ring member 74A, and the air supply path 74Ac The cold air can be supplied to the air supply pipe 35D of the metal mouth portion 28.

Therefore, the electric power for discharge is supplied to the discharge electrode through the power cable 33D, the annular member 74A, and the metal mouth portion 28, and the cold air is transmitted through the air supply pipe 35D and the air supply path 74Ac in the annular member 74A. It is supplied to the metal mouth portion 28. Thereby the metal mouth portion 28 is effectively cooled.

(2) The annular member 74A of the fourth embodiment has a front surface 74Af (first terminal portion) to which the power cable 33D is connected, and a supply air duct 35D, and is connected to the air supply path 74Ac. Open screw portion 74Ad (second terminal portion). Therefore, the power cable 33D and the air supply pipe 35D can be easily connected.

(3) As shown in Fig. 5, the metal mouth portion 28 is coupled to the longitudinal direction L side of the glass tube 25, and the screw portion 74Ad of the annular member 74A (see FIG. 4B) is relative to the annular member. The 74A is mounted in a direction orthogonal to the longitudinal direction L (which may also be a crossing direction). Therefore, the air blowing pipe 35D of the fourth A drawing can be connected to the annular member 74A (the first connecting mechanism 73A) in the direction orthogonal to the longitudinal direction L. Therefore, the air blowing pipe 35D can be used. The second focus P2 of the elliptical mirror 2 of one figure is separated and arranged. Therefore, since the amount of light blocking from the discharge lamp 1 by the air supply pipe 35D (connection cable 72) can be reduced, the light use efficiency is high, and the amount of heat generated by the exposure light source 30 is reduced.

Further, in this example, since the power cable 33D is connected to the annular member 74A substantially in parallel with the air blowing pipe 35D, the power cable 33D can be separated by the second focus P2 of the elliptical mirror 2 and disposed. Therefore, the amount of light blocking from the discharge lamp 1 can be further reduced.

(4) The screw portion 74Ad of the annular member 74A of the fourth embodiment is attached to the screw portion 76Ab of the first air blowing terminal 76A of the air supply pipe 35D. Therefore, the air blowing pipe 35D can be quickly and stably coupled to the annular member 74A by screwing of the screws.

(5) Further, the upper surface 74Af of the annular member 74A forms a flat portion for screwing the screw portion 74Ag of the first terminal 77A of the power cable 33D. Tan. Therefore, the power cable 33D can be quickly and stably coupled to the annular member 74A.

(6) Further, in this example, the flow path bending member 71 having the fitting portion 71b is provided through the lid member 50 on the metal mouth portion 28 of the third A diagram, and the annular member 74A of the fourth A diagram has The fitting hole 71Aa of the fitting portion 71b and the slit portion 74Ab provided so as to traverse the through hole 74Aa are fitted into the fitting portion 71b. A rod 75A that binds the slit portion 74Ab is provided. Therefore, the attachment and detachment of the annular member 74A with respect to the flow path bending member 71 can be easily and in a short time by merely restraining or loosening the rod 75A.

(7) Further, the air blowing path 74Ac of the annular member 74A communicates between the cover member 50 and the metal mouth portion 28. Therefore, the metal mouth portion 28 can be effectively cooled.

(8) Further, in this example, cold air is supplied to the glass tube 25 side through the cover member 50 of the third B diagram and the metal mouth portion 28. As described above, the glass tube 25 can be cooled by supplying the air cooled by the metal mouth portion 28 on the side of the glass tube 25. In this regard, by cooling the front end portion 50ca of the cylindrical portion 50c of the lid member 50 more than the metal mouth portion 28, the cooling effect on the glass tube 25 can be improved. However, for example, in the case where the amount of air blow is large, it is not always necessary to extend the tip end portion 50ca more than the metal mouth portion 28.

Among them, a cooled liquid (pure water, hydrogen-based inert liquid, etc.) may be used instead of cold air (or other gas). In addition, a recovery path for collecting the liquid flowing through the surface of the metal mouth portion 28 and re-cooling the liquid to the air supply pipe 35D (in this case, the liquid supply pipe) may be provided.

(9) Further, a groove portion 28b serving as a blowing path is formed in a spiral shape on the surface of the shaft portion 28a of the metal mouth portion 28 between the lid member 50 and the metal mouth portion 28 of the third drawing. The cooling efficiency of the metal mouth portion 28 can be improved by blowing air in a spiral shape on the surface of the metal mouth portion 28 as described above.

In addition, a spiral groove portion may be formed in a region facing the shaft portion 28a of the cylindrical portion 50c of the lid member 50, instead of providing the groove portion 28b on the side of the shaft portion 28a of the metal mouth portion 28 as described above. With this configuration, the cooling efficiency of the metal mouth portion 28 can also be improved.

(10) Further, the mounting portion 28c is provided at the upper end of the metal mouth portion 28 of the third drawing B, and the spiral groove portion 28b communicates with the groove portion 28e provided on the side surface of the mounting portion 28c. Therefore, the cover member 50, the flow path bending member 71, the annular member 74A, and the like can be provided on the mounting portion 28c, and the air supply from the annular member 74A can be transmitted through the opening 50b of the cover member 50 and the groove portion 28e thereof. The cold air of the air passage 74c of the road 74Ac and the flow path bending member 71 is guided to the groove portion 28b on the side surface of the metal mouth portion 28.

(11) In addition, the connecting cable 72 of the fourth embodiment is connected to a connection cable for the discharge lamp 1 and the air blowing device 34 and the power source 32 using cold air and electric power, and is formed of a conductive material and is detachable. The annular member 74A of the discharge lamp 1 (flow path bending member 71); the air supply pipe 35D having the one end fixed to the annular member 74A and formed of a flexible material, and having the cold air blowing path; The air supply pipe 35D is separately provided, and one end is fixed to the annular member 74A, and a power cable 33D formed of a conductive flexible material is provided.

According to the connection cable 72, the electric power from the power source 32 is supplied to the discharge lamp 1 side through the power cable 33D and the annular member 74A, and the cold air from the air blowing device 34 passes through the air supply pipe 35D and the ring member 74A (air supply path). 74Ac) is supplied to the discharge lamp 1. Therefore, through Power and cold air can be easily supplied to the discharge lamp 1 through an annular member 74A.

(12) In addition, the power cable 33D is a mesh-like member in which a large number of wires are formed, so that flexibility and conductivity can be easily achieved.

However, the outer side of the power cable 33D may be covered with a flexible insulating material. Further, as the power cable 33D, a wire or the like which is covered with a general insulating material may be used.

(13) The annular member 74A includes a screw portion 74Ad that connects the upper surface 74Af of the power cable 33D, and the air supply pipe 35D, and has a cold air supply path 74Ac formed therein. Therefore, the power cable 33D and the air supply pipe 35D can be easily connected to the annular member 74A.

(14) The annular member 74A is a disk-shaped member in which the through hole 74Aa is formed in the center portion, and a screw portion 74Ad that connects the air blowing pipe 35D is formed on the side surface of the disk-shaped member. Therefore, when the annular member 74A is mounted on the discharge lamp 1, it can be in a direction orthogonal to the longitudinal direction L of the discharge lamp 1 (see FIG. 2A), that is, the elliptical mirror 2 of the first figure. Since the second focus P2 is connected to the air supply pipe 35D in the direction away from the air, the amount of light blocking by the discharge lamp 1 shielded by the air supply pipe 35D can be reduced.

(15) The hollow first air blowing terminal 76A in which the screw portion 76Ab is formed is fixed to one end of the air blowing pipe 35D, and the screw portion 74Ad of the ring member 74A is screwed to the screw portion 76Ab of the first air blowing terminal 76A. . Therefore, the air blowing pipe 35D can be easily coupled to the annular member 74A through the first air blowing terminal 76A.

(16) Further, a first terminal 77A including a flat plate portion in which an opening is formed is fixed to one end of the power cable 33D, and the upper surface of the annular member 74A is fixed The 74Af is formed into a flat portion for screwing the screw portion 74Ag of the flat plate portion of the first terminal 77A. Therefore, the power cable 33D can be fixed to the upper surface 74Af through the flat plate portion easily and stably.

(17) Further, the exposure light source 30 of the present embodiment is connected to the power source 32 of the fifth diagram and the air blowing device 34, and as shown in FIG. 5, includes a glass tube 25 having a discharge electrode, and is connected to The discharge lamp 1 of the metal mouth portion 28 of the glass tube 25; and the connection cable 72, the annular member 74A that connects the cable 72 is attached to the metal mouth portion 28 of the discharge lamp 1, and the cold air supply path 74Ac is formed in the annular member 74A. The power cable 33D and the ring member 74A of the connection cable 72 are supplied with electric power from the power source 32 to the metal mouth portion 28, and through the air supply pipe 35D and the ring member 74A of the connection cable 72, the air supply device 34 supplies the cold air to the metal port. Department 28.

Therefore, the electric power from the power source 32 is supplied from the metal port portion 28 to the discharge electrode in the glass tube 25, and the cold air from the air blowing device 34 is supplied to the metal port portion 28. Therefore, the cooling effect on the metal mouth portion 28 is large. Further, the cold air passes through the air supply path 74Ac provided in the annular member 74A in the vicinity of the metal mouth portion 28. Therefore, as shown in the present example, when the metal mouth portion 28 is located on the free end side, the amount of light that is generated by the discharge lamp 1 by the cold air supply pipe or the like is reduced, and the light use efficiency is high. Also, the temperature of the exposure light source 30 rises less.

(18) Further, the exposure apparatus of this example is an exposure apparatus that exposes the pattern of the reticle R to the wafer W (photosensitive substrate) by the exposure light generated by the discharge lamp 1, and the exposure light source 30 of this example is used. As an exposure light source. Therefore, the amount of light blocking from the discharge lamp 1 is reduced, and the illuminance of the exposure light can be increased to increase the throughput of the exposure step. In addition, the discharge lamp 1 can be effectively cooled, and the imaging distortion can be improved by reducing thermal deformation. Sex and so on.

Further, in the above embodiment, as shown in the third B, a spiral groove portion 28b is formed between the metal mouth portion 28 and the lid member 50. However, as shown in FIG. 6, a metal mouth portion 28A in which a groove portion or the like is not formed in the cylindrical shaft portion 28a may be used. In the configuration of the sixth embodiment, the air in the air passage 71c of the flow path bending member 71 passes through the groove portion 28e provided in one of the attachment portions 28c of the metal mouth portion 28A, and is in the cylinder of the shaft portion 28a and the cover member 50. The portion 50c is supplied to the space, and flows directly from the surface of the shaft portion 28a to the side of the rod portion 25c.

Further, the projection exposure apparatus (exposure apparatus) of the above embodiment can be optically adjusted by incorporating an illumination optical system including an exposure light source, a plurality of lenses, and the like, and a projection optical system into the exposure apparatus main body, and will be composed of a plurality of mechanical parts. The reticle stage or the wafer stage is mounted on the main body of the exposure apparatus, and the wiring or piping is connected, and even integrated adjustment (electrical adjustment, operation confirmation, etc.) is performed. Among them, the production of the projection exposure apparatus is preferably carried out in a clean room such as a controlled temperature and a cleanliness.

Further, a micro-element such as a semiconductor element is a step of performing a function of a micro-element and a performance design, a step of fabricating a photomask (a reticle) according to the design step, and a step of manufacturing a substrate as a substrate of the element; The process of exposing the pattern of the reticle to the substrate (wafer or the like), the process of developing the exposed substrate, and the heating (cure) of the developed substrate by the projection exposure apparatus of the above embodiment And a substrate processing step such as an etching process; a component assembly step (including a dicing process, a bonding process, a packaging process), an inspection step, and the like.

Wherein, the light source device of the present invention is in addition to the above step repetition (step The exposure light source of the scanning exposure type projection exposure apparatus (scanning stepper or the like) of the step-and-scan type may be applied to a projection exposure apparatus (such as a stepper). Further, the light source device of the present invention is also applicable to an exposure light source of a liquid immersion type exposure apparatus disclosed in International Publication No. 99/49504, International Publication No. 2004/019128, and the like. Further, the light source device of the present invention can also be applied to a light source of a device other than the light source device or the exposure device of the exposure device that does not use the projection optical system.

Here, in the above embodiment, the reticle (mask) on which the transfer pattern is formed is used, but the electronic material according to the pattern to be exposed may be used as shown in the disclosure of the specification of US Pat. No. 6,778,257. An electronic mask that forms a transmissive pattern or a reflective pattern is substituted for the reticle.

Further, the present invention is not limited to an exposure apparatus for manufacturing a semiconductor element, and may be used in an exposure apparatus for transferring a component pattern on a glass plate used in manufacturing a display including a liquid crystal display element or a plasma display, and manufacturing a thin film magnetic head. An exposure apparatus for transferring an element pattern onto a ceramic wafer, an exposure apparatus used for manufacturing an imaging element (CCD or the like), an organic EL, a micro device, a MEMS (Micro Electromechanical Systems), a DNA wafer, or the like. Further, the present invention can be applied not only to a micro device such as a semiconductor element but also to a mask used for a photo-exposure device, an EUV exposure device, or the like, and to an exposure device for transferring a circuit pattern to a glass substrate or a germanium wafer. .

Further, in the connection cable 72 of the fourth embodiment shown in the above embodiment, a device using electric power and cold air other than the exposure device may be connected to the power source 32 and the air blowing device 34 of the fifth diagram.

However, the present invention is not limited to the above embodiments, and various configurations can be made without departing from the gist of the invention. In addition, the disclosure of U.S. Provisional Application Serial No. 60/907,654, filed on Apr. 12, 2007, which is incorporated herein by reference in its entirety, is incorporated herein in its entirety.

1‧‧‧discharge lamp

2‧‧‧Elliptical mirror

25‧‧‧ glass tube

25a‧‧‧Valves

25c‧‧‧ Rod

26, 28‧‧‧Metal mouth

28b‧‧‧Ditch

30‧‧‧Exposure source

31‧‧‧Installation components

32‧‧‧Power supply

33D‧‧‧Power cable

34‧‧‧Air supply device

35D‧‧‧Air supply piping

50‧‧‧Cover components

71‧‧‧Flow path bending members

71c‧‧‧Airway

72‧‧‧Connected cable

73A‧‧‧First Linkage

73B‧‧‧Second Linking Agency

74A‧‧‧ ring members

74B‧‧‧ ring members

75A‧‧‧ rods

75B‧‧‧ rods

76A‧‧‧First air supply terminal

76B‧‧‧Second air supply terminal

The first drawing shows a schematic configuration of a projection exposure apparatus of an example of the embodiment.

The second A is a view showing a part of the discharge lamp 1 in the first drawing, and the second B is a cross-sectional view taken along line BB of the second A.

The third A is a top view showing the flow path bending member 71 on the metal mouth portion 28 side of the second A drawing, and the third B is a cross-sectional view showing the configuration in the vicinity of the metal mouth portion 28 of the second A drawing, the third C The figure is a side view of the main part of the third B diagram.

Fig. 4A is a view showing a part of the connecting cable 72 showing an example of the embodiment, and Fig. 4B is a side view showing the connecting mechanism 73A in Fig. 4A.

The fifth diagram shows a part of the state in which the power source 32 and the air blowing device 34 are connected to the discharge lamp 1 of the third B diagram through the connecting cable 72 of the fourth drawing.

The sixth drawing is a view showing a part of the configuration in the vicinity of the metal mouth portion of the modification of the embodiment.

1‧‧‧discharge lamp

25‧‧‧ glass tube

25c‧‧‧ Rod

28‧‧‧Metal mouth

28a‧‧‧Axis

28b‧‧‧Ditch

28d‧‧‧Gap section

28e‧‧‧Ditch Department

30‧‧‧Exposure source

32‧‧‧Power supply

33B‧‧‧Power Cable

34‧‧‧Air supply device

35D‧‧‧Air supply piping

40‧‧‧Installation components

40a‧‧‧ recess

44‧‧‧ bolt

45‧‧‧Pipe

46‧‧‧Power cable

47‧‧‧Flow path bending members

47a‧‧‧ Flat section

47b‧‧‧Mate

47c‧‧‧Airway

50‧‧‧Cover components

50b‧‧‧ openings

50c‧‧‧Cylinder

71‧‧‧Flow path bending members

71b‧‧‧Mate

71c‧‧‧Airway

72‧‧‧Connected cable

73A‧‧‧First Linkage

73B‧‧‧Second Linking Agency

74A‧‧‧ ring members

74Aa‧‧‧through hole

74Ac‧‧‧Airway

74B‧‧‧ ring members

74Ba‧‧‧through hole

74Bc‧‧‧Airway

76A‧‧‧First air supply terminal

76B‧‧‧Second air supply terminal

77A‧‧‧First terminal

77B‧‧‧second terminal

78A, 78B‧‧‧ bolts

A1 to A7‧‧‧ arrows

L‧‧‧Longside direction

Claims (13)

A discharge lamp comprising: a glass member, comprising a light-emitting portion formed to extend in a first direction; a first metal port member coupled to one end of the glass member in the first direction; and a second metal port member coupled to The glass member is at the other end portion of the first direction; wherein the first metal port member has a flange portion provided on a side connected to the glass member, and is orthogonal to the first direction The first shaft portion has a smaller outer shape than the flange portion, and the second metal port member includes a second shaft portion that is coupled to the glass member. And a connecting portion formed at an end of the second shaft portion; and a first groove portion formed in the mounting portion. The discharge lamp according to claim 1, wherein the second shaft portion of the second metal port member has a second groove portion that faces the glass member from the mounting portion side. The discharge lamp according to claim 2, wherein the second groove portion is formed spirally around the shaft in the first direction. The discharge lamp according to any one of claims 1 to 3, wherein the second shaft portion has a shape smaller than a shape of the outer portion of the mounting portion. The discharge lamp of claim 4, wherein the second shaft portion is formed in a cylindrical shape. The discharge lamp according to any one of claims 1 to 3, wherein the mounting portion is formed at an end portion of the second shaft portion via an annular notch portion. The discharge lamp according to claim 6, wherein the first groove portion and the second groove portion communicate with each other via the annular notch portion. The discharge lamp according to any one of claims 1 to 3, further comprising: a cover member covering at least a part of the second metal port member and detachably attached to the second metal port member; The connection member is attached to the cover member; and the first flow path is formed in the connection mechanism for supplying a cooling medium between the cover member and the second metal port member. The discharge lamp according to claim 8, comprising a second flow path formed between the cover member and the second metal port member, and transmitting through the first portion formed in the connection mechanism The first-class road supplies the cooling medium to the side of the glass member. The discharge lamp according to any one of claims 1 to 3, further comprising: a third shaft portion provided at an end of the first shaft portion of the first metal port member and the first metal port member Between the portions, the outer shape is smaller than the first axial portion; and the fourth shaft portion is provided on the end portion side of the first metal port member, and the outer shape is related to the orthogonal direction. The shape is smaller than the aforementioned flange portion and larger than the aforementioned third shaft portion. A discharge lamp according to claim 10, further comprising: a third groove portion provided in the first shaft portion, the one end side of the first shaft portion and the other end of the first shaft portion The side is connected. The discharge lamp according to claim 10, wherein the first metal port member is provided with the flange portion and the first shaft in sequence from an end side of the glass member to an end portion side of the first metal port member. a third shaft portion and the fourth shaft portion. The discharge lamp according to claim 12, wherein the fourth shaft portion has the same outer shape as the first shaft portion or is smaller than the first shaft portion.