KR100620170B1 - Illumination system of a exposure apparatus - Google Patents

Abstract

The present invention relates to an illumination system of an exposure apparatus, wherein a beam projected from a light source 110 is adjusted on a wafer stage 140 through a projection lens 130 by adjusting a beam position by an operation of a beam position adjusting mirror 150. An illumination system (100) of an exposure apparatus for projecting onto a located wafer, comprising: a first step motor (161) in which a rotation axis (161a) is horizontally coupled to one side of a beam position adjusting mirror (150); A second step motor 162 coupled to the body 161 b of the first step motor 161 so that the rotation shaft 162 a is horizontally orthogonal, and fixed at a predetermined position; When the beam passing through the projection lens 130 has the maximum energy and the uniformity required for the exposure, the beam is installed so that its center coincides with the position projected to one side of the wafer stage 140, and on the X and Y axes passing through the center. A TDI sensor 180 for imaging an area of the beam projected through the projection lens 130 and outputting it as a signal; The uniformy drives the first and second step motors 161 and 162 so that the center of the area of the beam coincides with the intersection point on the X and Y axes from the signal output from the TDI sensor 180 to be projected through the projection lens 130. It includes a tee controller 190, by reducing the defect of the wafer pattern by allowing the beam projected for the exposure process to automatically and accurately adjust the position of the beam to obtain the maximum energy and uniformity It has the effect of improving the yield of the wafer.

Description

ILLUMINATION SYSTEM OF A EXPOSURE APPARATUS

1 is a schematic diagram showing an illumination system of a conventional exposure apparatus,

2 is a block diagram showing an illumination system of the exposure apparatus according to the present invention,

3 is a perspective view showing main parts of an illumination system of an exposure apparatus according to the present invention;

4A and 4B are diagrams for explaining beam position adjustment of the illumination system of the exposure apparatus according to the present invention.

<Description of Symbols for Main Parts of Drawings>

110; Light source 121; First reflection mirror

122; Second reflection mirror 123; 3rd reflection mirror

130; Projection lens 140; Wafer stage

141; Wafer holder 150; Beam position adjustment mirror

161; First step motor 161a; Axis of rotation

161b; Body 162; 2nd step motor

162a; Axis of rotation 162b; Body

163; First coupling bracket 163a; Insert

164; Second coupling bracket 164a; Insert

165; Fixing bracket 170; Uniformity sensor                 

180; TDI sensor 190; Unity Controller

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination system of an exposure apparatus, and more particularly, an exposure apparatus for automatically and accurately adjusting a position of a beam so that a beam projected for an exposure process can obtain maximum energy and uniformity. Relates to an illumination system.

In general, an illumination system of an apparatus that performs an exposure process for manufacturing a semiconductor device uses a sensor that can measure the position on the X and Y axes of a beam projected for exposure to a beam position adjusting mirror based on the Y and X axes. By finely rotating by adjusting the position of the beam can be set to improve the uniformity of the beam.

Referring to the accompanying drawings, the illumination system of the conventional exposure apparatus is as follows.

1 is a schematic diagram showing an illumination system of a conventional exposure apparatus. As shown, the illumination system 10 of the conventional exposure apparatus is projected by reducing the pattern on the reticle (not shown) through the plurality of reflecting mirrors 12, 13, 14, the beam projected from the excimer laser light source 11 The projection lens 15 is projected onto the wafer holder 16a of the wafer stage 16 on which the wafer is seated.

On the other hand, in order to improve the uniformity of the beam projected from the excimer laser light source 11, the beam position adjusting mirror 17 is provided on the path of the beam movement, and a uniformity sensor on one side of the wafer stage 16. 18 is installed. Accordingly, the wafer stage 16 is moved in the X-axis and Y-axis so that the beam passing through the projection lens 15 reaches the uniformity sensor 18 and then the unit of the beam through the uniformity sensor 18. The position of the beam was adjusted by manually rotating the beam position adjusting mirror 17 on the Y-axis and the X-axis by checking that the pony was measured and displayed.

In the conventional illumination system of the exposure apparatus, when the diameter of the wafer performing the exposure process is small, the uniformity of the excimer laser light source with respect to the wafer is not so important, even when the beam position adjusting mirror 17 is manually operated. Not much time is spent on adjusting the beam position.

However, the larger the wafer, the greater the change in the excimer laser light source 11 of the illumination system 10. Therefore, when the beam position is manually adjusted by manipulating the beam position adjusting mirror 17, the energy and the uniformity of the necessary brightness are sufficient. It takes a lot of time to get, and it's hard to tune it properly

Therefore, the amount of energy and the uniformity of the light intensity due to the change in the position of the beam are not uniform, causing an error, causing a defect in the pattern of the wafer itself, thereby lowering the yield of the wafer.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to automatically and precisely and easily adjust the position of the beam so that the beam projected for the exposure process can obtain maximum energy and uniformity. The present invention provides an illumination system of an exposure apparatus that reduces defects in a wafer pattern to improve wafer yield.

In an illumination system of an exposure apparatus for realizing such an object, the present invention provides an illumination system of an exposure apparatus for projecting a beam projected from a light source onto a wafer positioned on a wafer stage through a projection lens by adjusting a beam position by operating a beam position adjusting mirror, A first step motor having a rotating shaft horizontally coupled to one side of the beam position adjusting mirror; A second step motor coupled to the body of the first step motor horizontally orthogonally, and fixed to a predetermined position; When the beam passing through the projection lens has the maximum energy and uniformity required for exposure, it is installed so that its center coincides with the position projected to one side of the wafer stage, and it projects through the projection lens on the X and Y axes passing through the center. A TDI sensor for imaging the area of the beam and outputting the signal; And a uniformity controller for driving the first and second step motors so that the center of the area of the beam coincides with the intersection point on the X axis and the Y axis from the signal output from the TDI sensor. .

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

2 is a configuration diagram showing an illumination system of the exposure apparatus according to the present invention, Figure 3 is a perspective view showing the main part of the illumination system of the exposure apparatus according to the present invention. As shown, the illumination system 100 of the exposure apparatus according to the present invention comprises a light source 110, first to third reflective mirrors 121, 122, 123 to switch the path of the beam projected from the light source 110, and 3 a projection lens 130 for projecting a beam reflected by the reflective mirror 123 to reduce a pattern on a reticle (not shown), and a wafer stage on which a beam passing through the projection lens 130 is projected; ), First and second step motors 161 and 162 for rotating the beam position adjusting mirror 150 and the beam position adjusting mirror 150 provided between the first and second reflecting mirrors 121 and 122 about two axes. ), And a uniformity sensor 170 installed on one side of the wafer stage 140 to measure the uniformity of the beam, and a TDI (Time Delay Integration) sensor to image and output an area of the beam as a signal. And a first step and a second step mode by receiving a signal output from the TDI sensor 180. A uniformity controller 190 that controls the data controllers 161 and 162.

An excimer laser is used as the light source 110, and the beam projected from the light source 110 is reflected by the first to third reflecting mirrors 121, 122, and 123 to switch the path and enter the projection lens 130. do.

The projection lens 130 projects the beam finally reflected by the third reflection mirror 123 to reduce the pattern on the reticle (not shown) to a predetermined ratio and project it onto the wafer (not shown) on the wafer stage 140. .

The wafer stage 140 is installed to be movable along the X-axis and the Y-axis, and a wafer holder 141 on which a wafer (not shown) on which an exposure process is performed is mounted is mounted on an upper side.

The beam position adjusting mirror 150 rotates the position of the beam projected on the wafer stage 140 by rotating about two axes X and Y that are orthogonal to each other on the horizontal plane by the first and second step motors 161 and 162. Adjust

The first step motor 161 is coupled to the rotation shaft 161a to one side of the beam position adjusting mirror 150 by the first coupling bracket 163.

One side of the first coupling bracket 163 is inserted and mounted to the beam position adjusting mirror 150, and the insertion part 163a is horizontally aligned so that the rotation shaft 161a of the first step motor 161 is inserted and coupled to one side. Is formed.

The second step motor 162 is coupled to the body 161b of the first step motor 161 by the second coupling bracket 164 so that the rotation axis 162a is perpendicular to the horizontal.

The second coupling bracket 164 is fitted to the body 161b of the first step motor 161, and an insertion part 164a is formed to which the rotation shaft 162a of the second step motor 162 is inserted and coupled to one side thereof. do.

The second step motor 162 is fixed at a predetermined position by a fixing bracket 165 to which the body 162b is inserted and coupled.

The first and second step motors 161 and 162 are controlled by the uniformity controller 190, are proportional to the rotation angle and the number of input pulses, and can precisely control the position or the speed control without using a feedback system. Accordingly, the first and second step motors 161 and 162 can precisely control the rotation of the beam position adjusting mirror 150 by precisely controlling the rotation angle according to the number of input pulses by the uniformity controller 190. .

The uniformity sensor 170 is installed at one side of the wafer stage 140 to project a beam passing through the projection lens 130 to measure the uniformity of the beam.                     

The TDI sensor 180 is installed on one side of the wafer stage 140, and is installed so that its center coincides with the projected position when the beam passing through the projection lens 130 has the maximum energy and uniformity required for exposure. .

In addition, the TDI sensor 180 images the area of the beam projected through the projection lens 130 on the X and Y axes passing through the center, and outputs the signal to the uniformity controller 190 as a signal.

The uniformity controller 190 is projected through the projection lens 130 from the signal output from the TDI sensor 180 at the intersection of the X and Y axes where the center of the area of the beam passes through the center of the TDI sensor 180. The first and second step motors 161 and 162 are driven to match.

The operation of the illumination system of the exposure apparatus having such a structure is performed as follows.

When the beam projected from the light source 110 is switched by the first to third reflective mirrors 121, 122, and 123, passes through the projection lens 130, and is projected onto the TDI sensor 180 installed in the wafer stage 140, the TDI sensor. An image 180 outputs a signal by imaging an area of the beam projected on the X and Y axes passing through the center.

The uniformity controller 190 which receives the signal from the TDI sensor 180 calculates the deviation from the deviation of the X- and Y-axis when the center of the region (a) of the projected beam is imaged as shown in FIG. 4A. 4a by controlling the rotation angles of the first and second step motors 161 and 162 for moving the region a of the projected beam to the region b whose center coincides with the intersection of the X and Y axes. As such, the center of the area (a) of the projected beam and the intersection of the X and Y axes are matched.

Therefore, the uniformity controller 190 controls the first and second step motors 161 and 162 to coincide with the intersection of the center of the area A of the projected beam with the X and Y axes of the TDI sensor 180. By adjusting the position adjustment mirror 150, the position of the beam can be automatically set so that the uniformity of the beam can be improved.

Meanwhile, in the present embodiment, the first step motor 161 rotates the beam position adjustment mirror 150 about the X axis during rotation by the rotation axis 161a coupled to the beam position control mirror 150 in the X axis direction. The area of the beam imaged by the TDI sensor 180 is moved along the Y axis, and the second step motor 162 has its rotation axis 162a at the Y axis of the body 161b of the first step motor 161. By being coupled in the direction, the beam position adjusting mirror 150 is rotated about the Y axis during rotation so that the area of the beam imaged by the TDI sensor 180 is moved along the X axis.

According to the preferred embodiment of the present invention as described above, the position of the beam is accurately and easily automatically adjusted so that the beam projected for the exposure process can obtain the maximum energy and uniformity.

As described above, the illumination system of the exposure apparatus according to the present invention is to adjust the position of the beam accurately and easily automatically so that the beam projected for the exposure process can obtain the maximum energy and uniformity. It has the effect of improving the yield of the wafer by reducing defects.                     

What has been described above is only one embodiment for implementing the illumination system of the exposure apparatus according to the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, the gist of the present invention Without departing from the technical spirit of the present invention to the extent that any person of ordinary skill in the art to which the present invention pertains various modifications can be made.

Claims (1)

An illumination system of an exposure apparatus for projecting a beam projected from a light source to a beam positioned on a wafer stage through a projection lens by adjusting the beam position by manipulating a beam position adjusting mirror, A first step motor having a rotating shaft horizontally coupled to one side of the beam position adjusting mirror; A second step motor coupled to the body of the first step motor horizontally orthogonally, and fixed to a predetermined position; When the beam passing through the projection lens has the maximum energy and uniformity required for the exposure, the beam is installed at a center coinciding with the position projected to one side of the wafer stage, and the projection lens is positioned on the X and Y axes passing through the center. A TDI sensor for imaging the area of the beam projected through and outputting it as a signal; A uniformity controller for driving the first and second step motors so that the center of the area of the beam that is projected through the projection lens from the signal output from the TDI sensor coincides with the intersection point on the X and Y axes; Illumination system of the exposure apparatus comprising a.

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