KR100781459B1 - Exposure apparatus and focusing method of exposure process using thereof - Google Patents

Abstract

An exposure apparatus and a focusing method in an exposure process using the same are provided to enhance performance of a semiconductor device by focusing preciously reticles as well as wafers. An exposure apparatus includes a beam generator(110), a reticle stage(120), a wafer stage(130), wafer focus detection units(141,142), reticle focus detection units(151,152), and a controller. The beam generator radiates laser beams for exposure process. The height of the reticle stage, whose reticles are supported to be located in a path of the laser beams from the beam generator, is adjusted by a reticle stage driver. The wafer stage holds a wafer to be exposed. The wafer and reticle focus detection units receive laser beams reflected from the wafer and reticle, and output detection signals so as to detect whether the wafer and reticle are focused, respectively. The controller receives the detection signals from the wafer and reticle focus detection units, and controls the wafer and reticle stage drivers.

Description

Exposure apparatus and focus method of exposure process using the same {EXPOSURE APPARATUS AND FOCUSING METHOD OF EXPOSURE PROCESS USING THEREOF}

1 is a schematic view showing an exposure apparatus according to the prior art,

2 is a view showing an exposure apparatus according to the present invention,

3 is a block diagram showing an exposure apparatus according to the present invention;

4 is a perspective view showing a reticle stage of the exposure apparatus according to the present invention;

5 and 6 are cross-sectional views showing the main portion of the reticle stage of the exposure apparatus according to the present invention,

7 is a flowchart illustrating a focus method of an exposure process according to the present invention.

<Description of Symbols for Main Parts of Drawings>

110: beam generator 120: reticle stage

121: reticle stage driving means 122: support surface

123: first reticle tilting means 123a, 124a, 125a, 126a: support pin

123b, 124b, 125b, 126b: Motor 124: Second reticle tilting means

125: third reticle tilting means 126: fourth reticle tilting means

130: wafer stage 131: wafer stage driving means

140: wafer focus detecting unit 141: first light emitting device

142: first light receiving element 150: reticle focus detecting unit

151: second light emitting element 152: second light receiving element

160: control unit

The present invention relates to an exposure apparatus and a focusing method of an exposure process using the same, and more particularly, an exposure apparatus and a focusing process of an exposure process using the same to precisely form a fine pattern on a wafer by precisely focusing a reticle together with the wafer. It is about a method.

In general, semiconductor devices are manufactured by performing various unit processes such as an exposure process, a diffusion process, an etching process, and a chemical vapor deposition process. In the unit process exposure process, a projection exposure apparatus which transfers a pattern of a reticle onto a wafer coated with a photoresist such as photoresist on a surface through a projection optical system is generally used. The reduced projection exposure apparatus, so-called stepper, which is placed on a dimensionally movable wafer stage and repeats an operation of stepping the wafer by the wafer stage and sequentially exposing the pattern of the reticle to each shot region on the wafer, It is coming true.

Referring to the accompanying drawings, a device used in a conventional exposure process is as follows.

1 is a schematic view showing an exposure apparatus according to the prior art. As shown, the exposure apparatus 10 according to the related art includes a beam generator 11 for irradiating a laser beam for an exposure process and a reticle R on a movement path of the laser beam irradiated from the beam generator 11. ), And the wafer stage 13 on which the pattern W on the reticle R is projected by being irradiated with a laser beam passing through the reticle R, and the wafer W to be exposed is seated on an upper surface thereof. It includes.

As described above, the conventional exposure apparatus 10 performs exposure by irradiating a laser beam from the beam generator 11 so that the pattern of the reticle R is projected onto the wafer W vacuum-adsorbed onto the wafer stage 13. do.

Meanwhile, the focus of the wafer W should be focused from the beam generator 11 before performing the exposure process. For this purpose, the wafer focus detection units 14a and 14b are provided on one side of the wafer W.

The wafer focus detecting units 14a and 14b receive a light emitting element 14a that outputs light of a predetermined wavelength obliquely toward the wafer W, and receives light that is output from the light emitting element 14a and reflected from the wafer W. And a light receiving element 14b for outputting a detection signal.

The light receiving element 14b outputs a detection signal according to the amount of light received, and the control unit (not shown) of the wafer stage 13 until the amount of light received from the light receiving element 14b reaches a preset amount. The wafer W is focused by raising and lowering the wafer W by controlling the stage driving means 13a for adjusting the height.

However, in the conventional exposure apparatus 10, as the pattern size of the semiconductor element becomes smaller and smaller, the focus management of the wafer W becomes more important, but only the wafer focus detecting portions 14a and 14b are minute on the wafer W. There is a limit to exposing a pattern accurately. Therefore, it is necessary to develop an exposure apparatus capable of focus management for accurately forming a fine pattern on the wafer W.

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 bring the yield of a wafer by precisely forming a fine pattern on the wafer by accurately refocusing the reticle with the wafer, and the performance of the semiconductor device. The present invention provides an exposure apparatus that brings an improvement and a focusing method of an exposure process using the same.

In the exposure apparatus, the present invention provides a beam generator for irradiating a laser beam for an exposure process, and a reticle stage drive while supporting a reticle on a path of a laser beam irradiated from the beam generator. A reticle stage whose height is adjusted by means, a wafer stage which is exposed by being irradiated with a laser beam passing through the reticle, and a wafer stage whose height is adjusted by a wafer stage driving means, and light reflected by irradiating light onto the wafer A wafer focus detection unit for receiving a light and outputting a detection signal to detect whether the wafer is in focus, a reticle focus detection unit for receiving the reflected light by irradiating light to the reticle and outputting a detection signal to detect whether the reticle is in focus; From the wafer focus detector and the reticle focus detector Receiving receive signals respectively to the focus of the wafer and reticle, it characterized in that a control unit for respectively controlling the wafer stage and the reticle stage driving means drive means.

In addition, in the focus method of the exposure process, the present invention relates to a wafer incidence step of injecting light toward a wafer and to determine whether an amount of light reaching a predetermined point by being incident by the wafer incidence step and reflected from the wafer is equal to or greater than a first set amount. The first determination step, the wafer movement step of moving the wafer up and down so that the light amount is equal to or greater than the first set amount if the light amount is less than the first set amount in the first determination step, and the light amount is set first in the first determination step. A reticle incident step of injecting light into the reticle if it is equal to or more than a second amount; a second determination step of determining whether the amount of light incident by the reticle incident step and reflected from the reticle to reach a predetermined point is greater than or equal to the second set amount; If the amount of light is less than the second set amount in the reticle moving step of moving the reticle up and down so that the light amount is more than the second set amount Characterized in that it also.

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 view showing an exposure apparatus according to the present invention, Figure 3 is a block diagram showing an exposure apparatus according to the present invention, Figure 4 is a perspective view showing a reticle stage of the exposure apparatus according to the present invention. As shown, the exposure apparatus 100 according to the present invention supports the beam generator 110 for irradiating the laser beam and the reticle R to be positioned on the path of the laser beam irradiated from the beam generator 110. The reticle stage 120, the wafer stage 130 on which the exposed wafer W is exposed by being irradiated with the laser beam passing through the reticle R, and the wafer focus detecting unit for detecting the focus of the wafer W Receiving a detection signal from the 140, the reticle focus detection unit 150 for detecting the focus of the reticle (R), the wafer focus detection unit 140 and the reticle focus detection unit 150, and driving the wafer stage And a control unit 160 for controlling the means 131 and the reticle stage driving means 121, respectively.

The beam generator 110 projects the laser beam onto the reticle R so that the pattern on the reticle R is projected and exposed on the wafer W, and a plurality of beams for adjusting the path of the beam irradiated from the beam generator 110 are exposed. It may include a mirror (not shown) and a projection lens (not shown) for reducing and projecting the pattern on the reticle (R).

Reticle stage 120 is installed on the path of the laser beam irradiated from the beam generator 110, the opening is formed so that the laser beam is irradiated to the wafer (W) through the reticle (R), the reticle around the opening A support surface 122 for supporting the edge of (R) is formed, and the height is adjusted by moving up and down together with the reticle R by the reticle stage driving means 121.

The reticle stage driving means 121 may include a motor and a switching member such as a rack and pinion or a ball screw and a lead screw for converting the rotational force of the motor into a vertical linear motion. Actuators such as cylinders can be used.

The reticle stage 120 tilts the reticle R back and forth and left and right by moving the edge of the reticle R up and down on the support surface 122 supporting the edge of the reticle R, and the control unit 160. A plurality of reticle tilting means (123, 124, 125, 126) are controlled.

Reticle tilting means (123, 124, 125, 126) is provided on the support surface 122 so that a large number of each side of the reticle (R). That is, the reticle tilting means (123, 124, 125, 126) is composed of the first to fourth reticle tilting means (123, 124, 125, 126) to elevate the sides of the reticle (R) and each of the first to fourth reticle tilting means (123, 124, 125, 126) is a reticle (R) Is provided on the support surface 122 to support each side of the plurality to support each side, in this embodiment, since the reticle (R) has four sides, the minimum number of eight is provided, the reticle (R) of The reticle tilting means (123, 124, 125, 126) simultaneously supporting one side is supported by each side of the reticle (R) in a balanced manner by moving at the same time, thereby tilting the reticle (R) back and forth and left and right.

Each of the reticle tilting means 123, 124, 125, and 126 may be composed of various actuators for elevating one side of the edge of the reticle R. In this embodiment, the reticle tilting means 123, 124, 125, 126 is installed to move in the vertical direction while the rotation is suppressed on the support surface 122. The support pins 123a, 124a, 125a and 126a supporting the lower side of the reticle R and bolts screwed inside the support pins 123a, 124a, 125a and 126a are provided on the rotation shaft to rotate the rotation shaft. In accordance with the support pins (123a, 124a, 125a, 126a) includes lifting motors (123b, 124b, 125b, 126b).

The support pins 123a, 124a, 125a, and 126a may have a rectangular cross-sectional shape as in the present embodiment so as not to cause rotation on the support surface 122, but are not limited thereto and have a cross-sectional shape such as a polygon except a circle or the like. Unevenness may be coupled to the support surface 122 to be slidable up and down.

The motors 123b, 124b, 125b, and 126b may have a rotating shaft formed of bolts or a separate bolt may be inserted and fixed to the rotating shaft, and support pins 123a, 124a, 125a, and 126a screwed thereto according to the rotating direction of the rotating shaft. Lift).

The wafer stage 130 has a wafer W exposed by being irradiated with a laser beam passing through the reticle R on the upper surface, and the support surface or the support portion of the wafer W is moved by the wafer stage driving means 131. The height is adjusted together with the wafer W by moving up and down.

The wafer stage driving means 131 may include a motor for adjusting the height of the wafer W, and a switching member such as a rack and pinion or a ball screw and a lead screw for converting the rotational force of the motor into a vertical linear motion. An actuator such as a cylinder that operates by hydraulic pressure or pneumatic pressure is not limited to this.

The wafer focus detecting unit 140 receives light reflected by irradiating light onto the wafer W and outputs a detection signal to detect whether the wafer W is in focus.

The wafer focus detecting unit 140 is a first light emitting device 141 for obliquely outputting light of a predetermined wavelength toward the wafer W, and is output from the first light emitting device 141 and reflected from the reticle R. And a first light receiving element 142 that receives the light and outputs a detection signal according to the amount of light received to the controller 160.

The reticle focus detection unit 150 receives the reflected light by irradiating light onto the reticle R and outputs a detection signal to detect whether the reticle R is in focus.

The reticle focus detecting unit 150 includes a second light emitting element 151 for obliquely outputting light having a predetermined wavelength toward the reticle R, and light output from the second light emitting element 151 and reflected from the reticle R. And a second light receiving element 152 that receives the signal and outputs a detection signal according to the amount of light received to the controller 160.

The control unit 160 receives the detection signals from the wafer focus detecting unit 140 and the reticle focus detecting unit 150, respectively, so that the wafer stage driving means 131 and the reticle stage can focus on the wafer W and the reticle R. Each drive means 121 is controlled.

The control unit 160 detects output from the first and second light receiving elements 142 and 152 respectively, which are output from the first and second light emitting elements 141 and 151 and receive light reflected from the wafer W and the reticle R, respectively. The amount of light received by the first and second light receiving elements 142 and 152 is calculated based on the signal, and it is determined whether the wafer W and the reticle R are focused according to the amount of light.

The controller 160 controls the wafer stage driving means 131 and the reticle stage driving means 121 to adjust the height of the wafer W and the reticle R, thereby performing focus as well as the reticle focus detecting unit 150. The reticle tilting means (123, 124, 125, 126) by controlling each of the reticle tilting means (123, 124, 125, 126) by focusing the reticle (R) back and forth and left and right.

The operation of the exposure apparatus having such a structure will be described in detail by the description of the focus method of the exposure process according to the present invention.

7 is a flowchart illustrating a focus method of an exposure process according to the present invention. As shown, the focus method of the exposure process of the present invention is a focus method of not only the wafer W but also the reticle R in the exposure process, which includes a wafer incidence step S10, a first determination step S20, A wafer movement step S30, a reticle entrance step S40, a second determination step S50, and a reticle movement step S60 are included.

In the wafer incidence step S10, the first light emitting device 141 of the wafer focus detecting unit 140 is obliquely incident light toward the wafer W loaded on the wafer stage 130.

The first determination step S20 is incident on the wafer incidence step S10 and reflected from the wafer W, so that light is transmitted to the first light receiving element 142 located at a predetermined point, that is, opposite to the first light emitting element 141. By this, the controller 160 receives the detection signal corresponding to the amount of light reaching the first light receiving element 142 and determines whether the amount of light reaching the first light receiving element 142 is equal to or greater than a first predetermined amount. At this time, when the wafer W reaches the position where the desired focus is completed, the first set amount is irradiated from the first light emitting element 141 and reflected on the wafer W to reach the first light receiving element 142. to be.

In the wafer movement step S30, if the amount of light is less than the first set amount in the first determination step S20, the controller 160 controls the wafer stage driving means 131 so that the amount of light is equal to or greater than the first set amount. 130 and the height of the wafer (W) is adjusted.

When the reticle incident step S40 finishes the focus on the wafer W, that is, the amount of light reaching the first light receiving element 142 by the controller 160 in the first determination step S20 is greater than or equal to the first set amount. When it is determined, the second light emitting element 151 of the reticle focus detecting unit 150 injects the light obliquely into the reticle R.

The second determination step S50 arrives at the point determined by being incident by the reticle incident step S40 and reflected from the reticle R, that is, the second light receiving element 152 positioned opposite to the second light emitting element 151. The controller 160 receiving the detection signal corresponding to the amount of light to determine whether the amount of light is greater than or equal to the second set amount. At this time, the second set amount is irradiated from the second light emitting element 151 when the reticle R reaches the position where the desired focus is primarily completed, is reflected by the reticle R, and is reflected to the second light receiving element 152. The amount of light to reach.

In the reticle moving step S60, if the amount of light is less than the second set amount in the second determination step S50, the controller 160 controls the reticle stage driving means 121 to control the reticle stage driving means 121 so that the amount of light becomes more than the second set amount. The reticle R is moved up and down together with 120 to finish the focus of the reticle R first.

Meanwhile, the fine focus of the reticle R may be performed by tilting the reticle R back and forth and left and right. For this purpose, the third reticle step S70 and the reticle tilting step S80 may be further included.

If the amount of light reaching the second light receiving element 152 is greater than or equal to the second set amount in the second determination step S50, the third determination step S70 may detect a detection signal corresponding to the amount of light reaching the second light receiving element 152. The receiving control unit 160 determines whether the amount of light reaching the second light receiving element 152 is greater than or equal to the third set amount. At this time, the third set amount is greater than the second set amount, and when the reticle R reaches the position where the second precise focus is completed, the third set amount is irradiated from the second light emitting element 151 and reflected on the reticle R. And the amount of light reaching the second light receiving element 152.

In the reticle tilting step S80, when the light amount is less than the third set amount in the third determination step S70, the controller 160 controls the first to fourth to reticle tilting means 123, 124, 125, and 126 so that the light amount is greater than or equal to the third set amount. By driving the motors 123b, 124b, 125b, and 126b of each of the supporting pins 123a, 124a, 125a, and 126a, the reticle R is moved to one side as shown in FIG. , Respectively, by tilting backward, left, or right so that the amount of light reflected from the reticle R and reaching the second light receiving element 152 is equal to or greater than the third set amount.

When the amount of light reaching the second light receiving element 152 is equal to or greater than the third set amount as in the third determination step S70, the focus on the reticle R is finished.

As described above, according to the preferred embodiment of the present invention, by accurately focusing the reticle together with the wafer to precisely form a fine pattern on the wafer, the yield of the wafer is brought and the performance of the semiconductor device is improved.

As described above, the exposure apparatus and the focusing method of the exposure process using the same according to the present invention bring the yield of the wafer by accurately forming a fine pattern on the wafer by accurately focusing the reticle with the wafer, It has the effect of improving performance.

What has been described above is only one embodiment for carrying out the exposure apparatus and the focusing method of the exposure process using the same according to the present invention, the present invention is not limited to the above-described embodiment, it is claimed in the claims As will be apparent to those skilled in the art to which the present invention pertains without departing from the gist of the present invention, the technical spirit of the present invention may be changed to the extent that various modifications can be made.

Claims (9)

In the exposure apparatus, A beam generator for irradiating a laser beam for the exposure process, A reticle stage which is supported so that the reticle is positioned on the path of the laser beam irradiated from the beam generator and whose height is adjusted by the reticle stage driving means; A wafer stage on which the wafer exposed by being irradiated with the laser beam passing through the reticle is settled, and whose height is adjusted by a wafer stage driving means; A wafer focus detector for receiving light reflected by irradiating light onto the wafer and outputting a detection signal to detect whether the wafer is in focus; A reticle focus detector for receiving light reflected from the reticle and outputting a detection signal to detect whether the reticle is in focus; A control unit for receiving the detection signals from the wafer focus detection unit and the reticle focus detection unit to control the wafer stage driving means and the reticle stage driving means for focusing the wafer and the reticle, respectively Exposure apparatus comprising a. The method of claim 1, The reticle stage, Tilting the reticle back and forth and left and right by moving the edge of the reticle up and down on a supporting surface supporting the edge of the reticle, and providing a plurality of reticle tilting means controlled by the controller. Exposure apparatus characterized in that. The method of claim 2, The reticle tilting means, Mounted on the support surface such that a plurality of sides of each of the reticles are supported Exposure apparatus characterized in that. The method of claim 2, The control unit, Tilting the reticle by controlling each of the reticle tilting means in accordance with a detection signal received from the reticle focus detection unit Exposure apparatus characterized in that. The method of claim 2 or 3, The reticle tilting means, A support pin installed to move in a vertical direction in a state in which rotation is suppressed on the support surface, and supporting a lower side of the reticle; A bolt that is screwed to the inside of the support pin is provided on the rotary shaft to lift the support pin in accordance with the rotation direction of the rotary shaft Exposure apparatus comprising a. The method of claim 1, The reticle focus detection unit, A second light emitting device for obliquely outputting light of a predetermined wavelength toward the reticle; A second light receiving element which receives light reflected from the second light emitting element and reflected from the reticle and outputs a detection signal according to the amount of light received to the controller; Exposure apparatus comprising a. The method of claim 6, The control unit, Calculating an amount of light received by the second light receiving element based on a detection signal output from the second light receiving element, and determining whether the reticle is in focus according to the light amount Exposure apparatus characterized in that. In the focus method of the exposure step, A wafer incidence step of injecting light toward the wafer, A first determination step of determining whether an amount of light incident by the wafer incidence step and reflected from the wafer to reach a predetermined point is greater than or equal to a first predetermined amount; A wafer movement step of moving the wafer up and down so that the light amount is equal to or greater than the first set amount if the amount of light is less than the first set amount in the first determination step; A reticle incident step of injecting light into the reticle if the amount of light is equal to or greater than the first predetermined amount in the first determination step; A second determination step of determining whether the amount of light incident by the reticle incident step and reflected from the reticle to reach a predetermined point is greater than or equal to a second predetermined amount; A reticle moving step of moving the reticle up and down so that the light amount is greater than or equal to the second set amount if the amount of light is less than the second set amount in the second determination step; Focus method of the exposure process comprising a. The method of claim 8, A third judging step of judging whether the light amount is at least a third set amount if the amount of light is at least a second set amount in the second judging step; A reticle tilting step of tilting the reticle back and forth and left and right so that the light amount is equal to or greater than the third set amount when the amount of light is less than a third set amount in the third determination step; Focus method of the exposure process comprising a.

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