JP2005292214A - Cylindrical surface exposure device and system therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical surface exposure device and a system therefor that can precisely transfer a pattern to a cylindrical surface. <P>SOLUTION: The cylindrical surface exposure device has a light source part 2, a slit 3 which has an opening to pass light from the light source part2, a lens which is arranged below the slit 3 and converges light passing through the slit 3, a mask 4 which is arranged below the lens and forms a desired pattern, a rotation part 8 which is arranged below the mask 4 and detachably supports a cylinder part 5, a 1st motor 12 which drives the mask 4, and a 2nd motor 12 which drives the rotation part 8, wherein the lens is arranged at a place where mapping of the slit 3 is imaged nearly on the same surface as that of the mask 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cylindrical surface exposure apparatus and system for transferring a pattern onto a cylindrical surface such as a stent, and more particularly to a cylindrical surface exposure apparatus and system for transferring a pattern with high accuracy by preventing light diffusion.

In general, a fine pattern is transferred to a non-planar cylindrical surface by placing a mask for forming a pattern on a cylindrical surface coated with a resist and irradiating light to expose the resist. A stent manufacturing process using this exposure method will be described with reference to FIG. FIGS. 3A to 3D are conceptual views showing a normal stent manufacturing process of the cylindrical surface exposure method.
First, as shown in FIG. 3A, a resist 22 is uniformly coated on a metal tube 21 which is the original shape of a stent. Next, as shown in FIG. 3B, the pattern is transferred onto the cylindrical surface by exposure. Then, as shown in FIG. 3 (c), after development, the metal portion to which the pattern has been transferred is etched by being immersed in a processing solution. Finally, when the resist 22 is removed in FIG. 3D, the stent 23 having a desired shape is completed.

  Here, the exposure method of FIG. 3B will be described in detail. In FIG. 3 (b), the illumination light 17 passes through the opening 18 of the slit 3, passes through a portion of the mask glass 16 placed below the slit 3 without the pattern of the mask 4, and is on the metal tube 21. The resist 22 is exposed. The mask glass 16 is formed with a pattern for one round of the metal tube 21, and the mask glass 16 moves rightward in the drawing at a speed v. Further, in synchronism with the moving speed v, the metal tube 21 rotates at an angular velocity ω in the clockwise direction in the drawing, and the circumferential direction of the metal tube 21 is exposed.

However, in the exposure to the cylindrical surface, the resolution is reduced due to the cause as shown in FIG. FIG. 4A is a conceptual diagram for explaining a reduction in resolution due to light diffraction, and FIG. 4B is a conceptual diagram for explaining a reduction in resolution due to multiple reflection.
In FIG. 4A, at the end of the opening of the slit through which the illumination light 17 passes, the light is diffracted as the distance between the mask 4 on the mask glass 16 and the cylindrical surface of the work 5 increases, and the pattern Blur has occurred.
Further, in FIG. 4B, since the mask glass 16 and the cylindrical surface are not parallel, the light is multiply reflected and the exposure range is expanded. It is known that such a decrease in resolution is improved by narrowing the opening width 18 of the slit shown in FIG. 3B. However, as shown in FIG. 4C, the thickness of the mask glass 16 is reduced. Since light is also diffracted in the vertical direction, it is difficult to improve the resolution only by reducing the opening width 18 of the slit.
Various techniques have been proposed for improving the resolution in such exposure, although not limited to the exposure technique for the cylindrical surface.

For example, in Patent Document 1, when a pattern formed on a mask is transferred onto a substrate to be processed via a projection optical system, the projection area of the mask is limited by a slit, and the slit is relative to the mask and the substrate. In addition, a “scanning exposure method” is disclosed in which the entire pattern area of the mask is transferred onto the substrate by scanning at least twice under different exposure conditions.
In the invention disclosed in Patent Document 1, in the first and second exposure of the entire mask, the focal position of the projection optical system is changed, the mask and the substrate are tilted relatively, and the relative scanning of the slits is performed. Multiple exposure can be performed by reversing the direction, changing the exposure amount, or changing the coherency factor or numerical aperture of the illumination optical system. Also, with this technique, the pattern transfer accuracy can be improved by adjusting the coherency factor and exposure amount of the illumination system for each focal position necessary for optimization of multiple exposure. The required time can be shortened by reversing the first and second scanning directions.

Further, Patent Document 2 discloses an electron gun having an electron source in which the central portion of the electron emission surface has a concave shape, and a projection for reducing and projecting an electron beam irradiated from the electron gun and transmitted through a mask onto a wafer. An “electron beam transfer exposure apparatus” having a lens is disclosed.
In the invention disclosed in Patent Document 2, by using ring-shaped electrons irradiated from the peripheral portion of the electron emission surface having a concave central portion for exposure, blurring of the electron beam is removed and exposure is performed. The area can be enlarged. In addition, since this ring-shaped electron beam has high brightness and can obtain the electron beam intensity necessary for exposure even if the exposure area is enlarged, an electron beam transfer exposure apparatus with high productivity can be realized. Furthermore, by arranging an arc-shaped slit member between the electron gun and the mask, a ring-shaped electron beam irradiated from the electron gun can be used efficiently.

Patent Document 3 discloses a light source, a photomask on which a required pattern is formed, a slit that restricts light from the photomask, a projection lens that projects slit light onto a work, and a photomask as a slit. There is disclosed a “scanning projection exposure apparatus” comprising means for moving the photomask, means for moving the work in synchronization with the movement of the photomask, and speed changing means for changing the moving speed ratio of the photomask and the work. Yes.
Since the invention disclosed in Patent Document 3 includes a speed change means for changing the moving speed of the photomask and the moving speed of the workpiece, the projection magnification in the moving direction can be changed by changing the relative moving speed of both. Can be changed arbitrarily. Therefore, the aspect ratio of the projected pattern on the workpiece can be arbitrarily adjusted with one photomask.

  However, in the conventional technique described in Patent Document 1, a lens, which is a projection optical system, is placed below the mask and the slit, and an image of the mask is formed on the substrate to be processed by the lens and projected. In this method, it is possible to narrow the exposure range to some extent, but it is difficult to provide a slit fixed to a moving mask on substantially the same plane. When applied to a cylindrical surface, the end of the opening of the slit is difficult. The problem that blur occurs in the part remains.

  In addition, the conventional technique described in Patent Document 2 is to devise the shape of the electron emission surface for the purpose of microfabrication in the semiconductor manufacturing field, and to efficiently collect the electron beam at a necessary place. There was a problem that the reduction in resolution on the cylindrical surface could not be solved without assuming a cylindrical shape. In addition, since the mask and the transfer surface are not scanned, there is a problem that the cylindrical surface cannot be continuously exposed in the circumferential direction.

In the prior art described in Patent Document 3, a lens is certainly provided behind the slit and a mask image is projected onto the transfer surface. This lens forms a mask image at an arbitrary projection magnification. There is a problem that the spread due to light diffraction cannot be prevented directly.
JP 2002-43214 A Japanese Patent Laid-Open No. 11-86766 Japanese Utility Model Publication No. 5-81840

  The present invention has been made in view of such a conventional situation, and an object of the present invention is to provide a cylindrical surface exposure apparatus and system capable of accurately transferring a pattern to a cylindrical surface.

In order to achieve the above object, a cylindrical surface exposure apparatus according to a first aspect of the present invention includes a light source unit, a slit that allows light from the light source unit to pass through with an opening, and a slit disposed below the slit. A lens that collects light passing through the lens, a mask that is disposed below the lens to form a desired pattern, a rotating unit that is disposed below the mask and removably supports the cylindrical portion, and a first that drives the mask 1 and a second motor for driving the rotating portion, and the lens is disposed at a position where the image of the slit is imaged on substantially the same plane as the mask surface.
In the stent cylindrical surface exposure apparatus having the above-described configuration, the light passing through the opening of the slit is condensed by the lens and forms an image of the slit on substantially the same plane as the mask surface. Further, in synchronization with the cylindrical portion rotated by the second motor, the mask has a function of moving linearly by the first motor.

Further, the cylindrical surface exposure system according to the second aspect of the present invention includes a light source unit, a slit that allows light from the light source unit to pass therethrough, and light that is disposed below the slit and passes through the slit. A lens for condensing light, a mask that is disposed below the lens to form a desired pattern, a rotating unit that is disposed below the mask and removably supports the cylindrical portion, and a first motor that drives the mask , A second motor for driving the rotating unit, a first position adjusting unit for adjusting the position of the slit, a second position adjusting unit for adjusting the position of the mask, and a motor driving condition connected to the motor. And an input unit connected to the input unit for displaying and / or outputting driving conditions.
The stent cylindrical surface exposure system configured as described above has an effect that the mask and the slit are adjusted to appropriate positions by the first position adjustment unit and the second position adjustment unit, and as a result, between the slit and the mask. Light that passes through the opening of the slit is collected by the lens positioned, and has an action of forming an image of the slit on the substantially same plane as the mask surface. Further, the mask and the cylindrical portion are driven by the first motor and the second motor, respectively, and have the effect of performing the linear movement and the rotational movement in synchronization.

  In the cylindrical surface exposure apparatus according to the first aspect of the present invention, when the light projected from the light source passes through the opening of the slit, the light is condensed by the lens below the slit and is formed on the substantially same plane as the mask surface. Since the mapping is formed, light diffraction caused by the thickness of the mask glass can be suppressed. Therefore, the mask pattern can be accurately transferred even on a cylindrical surface which is a curved surface.

  In the cylindrical surface exposure system according to claim 2 of the present invention, since the slit and the mask are adjusted to the optimum positions in the position adjusting unit, the light projected from the light source and passing through the opening of the slit is a lens. It is condensed by. As a result, since light diffraction due to the thickness of the mask glass is suppressed, transfer on the cylindrical surface can be performed with high accuracy.

Embodiments of a cylindrical surface exposure apparatus and its system according to the present invention will be described below with reference to FIGS.
FIG. 1 is a schematic diagram of a cylindrical surface exposure apparatus system according to the present embodiment of the present invention.
In FIG. 1, a cylindrical surface exposure apparatus system 1 includes an ultraviolet light source 2, a slit 3, a mask 4, a work 5, a manual stage 6, an automatic linear motion stage 7, an automatic rotation stage 8, a motor controller 12, and a computer 13. Yes. Although not shown, a lens is installed between the slit 3 and the mask 4.
The mask 4 is formed by forming a pattern corresponding to one round of the workpiece 5 on the mask glass, and is detachably attached to the θ stage 11 a installed on the automatic linear motion stage 7. A motor controller 12 is connected to the automatic linear motion stage 7, and the mask 4 to be attached moves linearly. In addition to the θ stage 11a, an XY stage 9a and a Z stage 10a are installed on the automatic linear movement stage 7, and coordinate adjustment in the front and rear, right and left directions and up and down directions is possible in addition to the rotation direction of the mask 4 and the mask glass. It can be set manually.
In this embodiment, only the automatic linear stage 7 is connected to the motor controller 12 and driven while being automatically controlled. Of course, the θ stage 11a, the XY stage 9a, and the Z stage 10a are also driven by a motor with a controller. It is good.
The workpiece 5 has a cylindrical shape such as a metal tube whose surface is coated with a resist. The workpiece 5 is detachably attached to the automatic rotation stage 8 connected to the motor controller 12 to perform a rotational motion. The automatic rotation stage 8 is provided with a Z stage 10c and a θ stage 11b so that the coordinate adjustment in the horizontal direction with respect to the rotation axis of the work 5 and the distance between the mask 4 and the work 5 can be adjusted. .
Although not shown, the slit 3 has an opening that allows the irradiated light to pass therethrough, and is attached to the manual stage 6. Further, coordinate adjustment in the front-rear and left-right directions and the up-down direction of the slit 3 can be manually set by an XY stage 9b and a Z stage 10b installed on the manual stage 6.
The θ stage 11b, the Z stage 10c, the manual stage 6, and the XY stage 9b and the Z stage 10b installed on the manual stage 6 may be motor-driven with a controller.

As will be described later, the lens is positioned between the slit 3 and the mask 4 and collects the ultraviolet rays that pass through the slit 3 to form a mapping of the slit 3 on substantially the same plane as the mask 4 surface. . Then, the positions of the mask 4 and the slit 3 are adjusted using the position adjusting stages in the respective directions of the XY stages 9a and 9b, the Z stages 10a and 10b, and the θ stage 11a provided in the manual stage 6 and the automatic linear motion stage 7. By doing so, the lens is placed at an optimum position for focusing and imaging.
If the slit 3 or the mask 4 can be fixed at a position where the lens can be focused and imaged optimally, each direction of the XY stages 9a and 9b, the Z stages 10a and 10b, and the θ stage 11a can be achieved. These position adjustment stages may be appropriately deleted.
The motor controller 12 drives and controls the automatic linear motion stage 7 and the automatic rotation stage 8. The driving condition and the control condition can be input from a keyboard (not shown) according to the display on the display 14 of the connected computer 13. It is also possible to connect a printer or the like to the computer 13 to print the drive, control conditions, exposure conditions of the ultraviolet light source 2, and the like. However, the computer 13 is not necessarily connected.
The ultraviolet light source 2 irradiates a predetermined amount of ultraviolet light toward the work 5, and setting and control of conditions such as irradiation amount and irradiation time are performed by a computer 13 that is not shown. Note that the light source is not limited to ultraviolet rays, and may be selected in consideration of handling properties and costs as long as the resist coated on the workpiece 5 is appropriately exposed.

  In the exposure, the workpiece 5 rotates and the mask 4 moves linearly while being synchronized therewith. When the velocity of the mask 4 is v, the angular velocity of the workpiece 5 is ω, and the radius of the workpiece 5 is r, the relationship between the velocity of the mask 4 and the workpiece 5 is expressed by the following equation.

  The light emitted from the ultraviolet light source 2 passes through the opening of the slit 3 and transfers the pattern of the mask 4 onto the resist on the work 5. The opening width of the slit 3 and the projection magnification of the lens determine the irradiation area of the workpiece 5, and the angular velocity ω of the workpiece 5 is determined by the exposure time, the opening width of the slit 3, and the projection magnification of the lens. Assuming that the exposure time is t, the opening width of the slit 3 is L, and the projection magnification of the lens is α, the angular velocity ω of the workpiece 5 is expressed by a time expression.

Thus, in this embodiment, a complicated pattern of the mask 5 is transferred onto the work 5.
The present embodiment is mainly intended for the manufacture of stents. The exposed cylinder is subjected to a development process and an etching process to remove unnecessary metal portions, and the remaining resist is removed. When exfoliated, a stent having a fine shape is completed.

Next, a lens focusing method will be described with reference to FIG.
FIG. 2 is a conceptual diagram showing the function of the lens of the cylindrical surface exposure system according to the present embodiment.
In FIG. 2, in the present embodiment, the lens 15 is installed between the slit 3 and the mask glass 16 and has a function of condensing the illumination light 17.
When the irradiation light 17 from the light source passes through the opening 18 of the slit 3, the both ends of the opening 18 spread by diffraction as indicated by reference numerals 19a and 19b. However, these diffracted lights 19a and 19b are condensed when they reach the lens 15, and can return to one point of the pattern of the mask 4 on the mask glass 16 as indicated by reference numerals 20a and 20b. .
That is, since the lens 15 creates a mapping of the slit 3 at the pattern position of the mask 4 on the mask glass 16, an effect equivalent to the arrangement of the slit 3 at the pattern position is obtained, and the light from the slit 3 is obtained. In addition, the diffraction of light in the thickness direction of the mask glass 16 is also suppressed, and the pattern of the mask 4 can be accurately transferred to the work on the cylindrical surface.
The lens 15 can cope with not only equal magnification but also variable magnification due to reduction or enlargement.

  In this embodiment configured as described above, the lens is arranged between the slit and the mask so that the light to be diffracted is condensed and the mapping of the slit is formed on substantially the same plane as the mask. The pattern can be accurately transferred onto the cylindrical surface.

  As described above, the invention described in claims 1 and 2 of the present invention can provide a cylindrical surface exposure apparatus and system capable of accurately performing exposure on a cylindrical surface, such as a stent or the like. It can be used by a manufacturer of a cylinder having a minute shape.

It is the schematic of the cylindrical surface exposure system which concerns on this Embodiment of this invention. It is a conceptual diagram which shows the function of the lens of the cylindrical surface exposure system which concerns on this Embodiment. (A) thru | or (d) is a conceptual diagram which shows the stent manufacturing process for demonstrating the prior art of a cylindrical surface exposure method, respectively. (A) is a conceptual diagram for demonstrating the fall of the resolution by the diffraction of light, (b) is a conceptual diagram for demonstrating the fall of the resolution by multiple reflection.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cylindrical surface exposure system 2 ... Ultraviolet light source 3 ... Slit 4 ... Mask 5 ... Workpiece 6 ... Manual stage 7 ... Automatic linear motion stage 8 ... Automatic rotation stage 9a, 9b ... XY stage 10a, 10c ... Z stage 11a, 11b ... Theta stage 12 ... Motor controller 13 ... Computer 14 ... Display 15 ... Lens 16 ... Mask glass 17 ... Illumination light 18 ... Slit openings 19a, 19b ... Diffracted light 20a, 20b ... Condensed light 21 ... Metal tube 22 ... Resist 23 ... Stent

Claims (2)

  A light source unit, a slit that allows light from the light source unit to pass through with an opening, a lens that is disposed below the slit and collects light that passes through the slit, and a desired lens that is disposed below the lens. A mask for forming a pattern; a rotating unit disposed below the mask to removably support the cylindrical unit; a first motor for driving the mask; and a second motor for driving the rotating unit. The cylindrical surface exposure apparatus is characterized in that the lens is disposed at a position where an image of the slit is imaged on substantially the same plane as the mask surface. A light source unit, a slit that allows light from the light source unit to pass through with an opening, a lens that is disposed below the slit and collects light that passes through the slit, and a lens that is disposed below the lens and has a desired shape A mask for forming a pattern, a rotating part disposed below the mask and removably supporting a cylindrical part, a first motor for driving the mask, a second motor for driving the rotating part, A first position adjusting unit that adjusts the position of the slit; a second position adjusting unit that adjusts the position of the mask; an input unit that is connected to the motor and inputs a driving condition of the motor; and A cylindrical surface exposure system comprising a display unit connected and displaying and / or outputting the driving conditions.