KR20100083459A - Exposure apparatus and method to measure orthogonality thereof - Google Patents

Abstract

PURPOSE: An exposing device and a method for measuring orthogonality thereof are provided to measure and correct the orthogonality of a stage by using an optical unit installed on the exposing device without an additional measuring device. CONSTITUTION: A stage(18) transfers a substrate. An optical unit(66) generates a plurality of beams irradiated to a substrate. A controller(63) exposes a plurality of beams on the exposed part of the substrate while moving the stage. The orthogonality of the stage is measured by using the exposed result. A beam distance measuring unit(26) measures the distance between a plurality of exposed beams.

Description

Exposure apparatus and perpendicularity measuring method {EXPOSURE APPARATUS AND METHOD TO MEASURE ORTHOGONALITY THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and a method for measuring the squareness, and more particularly, to an exposure apparatus for measuring the squareness of a stage in a digital exposure apparatus and a method for measuring the squareness.

In general, a method of forming a pattern on a substrate constituting a flat panel display, such as a liquid crystal display device or a plasma display device, first applies a pattern material to the substrate, and selectively exposes the pattern material using a photo mask to change chemical properties. The pattern is formed by selectively removing the pattern material portion or other portions.

However, as the substrate becomes larger in size and the pattern formed on the exposure surface becomes more precise, a digital exposure apparatus that does not use a photo mask is used, and the digital exposure apparatus has pattern information made of an electrical signal using an electronic apparatus. The pattern is formed by transferring the light beam to the substrate.

Such a digital exposure apparatus forms a pattern on the exposure surface while moving the substrate, wherein the precision of the stage for moving the substrate affects the quality of the pattern formed on the exposure surface. In particular, the squareness of the stage is formed on the exposure surface. This will have a direct impact on the quality of the pattern.

In the prior art, a method of correcting the squareness of the stage by separately installing a mechanism for measuring a position error was used. At this time, correcting the squareness of the stage means correcting an error generated when the stage is shifted by a predetermined angle.

However, this method requires the installation of a separate instrument (eg an angle detector) for the measurement, resulting in mechanical installation errors and additional costs.

In addition, there is a problem of instrument interference in the measurement path and the instrument must be disassembled after disassembling and reassembling, and thus repeatability and reproducibility are insufficient during measurement, and the precision setting value can be lost by touching the stage when installing the instrument. none.

It is an object of the present invention to provide an exposure apparatus that measures and corrects the squareness of a stage using an optical unit that is a constituent device of a digital exposure apparatus without installing a separate measuring instrument.

To this end, the exposure apparatus according to an embodiment of the present invention exposes a plurality of beams on the exposure surface of the substrate while moving the substrate, an optical unit for generating a plurality of beams irradiated onto the substrate, and moving the stage, It includes a control unit for measuring the squareness of the stage using the exposed results.

The beam distance measuring unit measures a distance between the plurality of exposed beams, and the controller obtains an inclination value for measuring the squareness of the stage using the distances between the plurality of beams.

Here, the inclination value is obtained by Equation 1 below.

[Equation 1]

cosθ = (d _n '+ d _{n + 1} ') / (d _n + d _{n + 1} )

Here, d _n ', d _{n + 1} ' are actual distances between exposure beams continuously exposed, d _n , d _{n + 1} are distances between predetermined exposure beams, and θ is zero.

The optical unit also includes a digital micro mirror device for modulating the light emitted from the light source according to the pattern and irradiating the modulated light beam to the exposure surface.

In addition, the stage is moved at regular intervals along the scanning direction, and the control unit controls the plurality of beams to be continuously exposed to the exposure surface according to the driving of the stage moved at regular intervals.

To this end, the method for measuring the squareness of an exposure apparatus according to an embodiment of the present invention moves a stage mounted on a substrate, generates and irradiates a plurality of beams on the substrate of the stage, and exposes the plurality of beams on the exposure surface of the substrate. The squareness of the stage is measured.

In addition, the distance between the plurality of exposed beams is measured, and the slope value for measuring the squareness of the stage is determined using the distance between the plurality of beams.

Here, the inclination value is obtained by Equation 1 below.

[Equation 1]

cosθ = (d _n '+ d _{n + 1} ') / (d _n + d _{n + 1} )

Here, d _n ', d _{n + 1} ' are actual distances between exposure beams continuously exposed, d _n , d _{n + 1} are distances between predetermined exposure beams, and θ is zero.

As described above, according to the exposure apparatus and the method for measuring the squareness, the squareness of the stage can be more accurately corrected by measuring the squareness of the stage by measuring the distance between a plurality of exposure beams continuously exposed according to the driving of the stage. There are advantages to it.

In addition, there is an effect that can form a pattern more accurately by presenting such a more precise measurement and correction method.

In addition, the measurement method using the pattern of the exposure beam irrespective of the accuracy of the setting, it is also possible to move to a more precise measuring equipment such as SEM and measure.

1 is a perspective view showing a schematic configuration of an exposure apparatus according to an embodiment of the present invention.

In FIG. 1, the exposure apparatus 10 according to an embodiment of the present invention is formed in a flat bed type and is mounted on a thick plate-shaped mounting table 14 supported by four supporting parts 12, and on an upper portion of the mounting table 14. A stage 18 which is provided and is to be exposed, that is, a scanning function while moving the substrate 16 in the Y-axis direction, and two stages which are provided on the upper surface of the mounting table 14 and extended along the moving direction of the stage 18. And a guide 20. The stage 18 is provided so that its longitudinal direction may face the stage 18 movement direction, and is supported by the guide 20 so that reciprocation is possible.

The central portion of the mounting table 14 is provided with a U-shaped gate 22 so as to span the movement path of the stage 18, and each end of the gate 22 is fixed to both sides of the mounting table 14. An optical unit 24 for generating a beam exposed to the substrate 16 is provided on one side with the gate 22 interposed therebetween, and a plurality (eg, a distance for measuring the distance of the beam exposed to the substrate 16 on the other side). For example, two beam distance measuring units 26 are provided. The optical unit 24 and the beam distance measuring unit 26 are attached to the gate 22 and fixedly arranged above the movement path of the stage 18.

The optical unit 24 space-modulates the laser light emitted from the light source 30 in accordance with a desired pattern, and irradiates the modulated laser light to the substrate 16 having the exposure surface 17 as an exposure beam. A plurality of exposure heads 28 which expose 16 are provided, and each exposure head 28 is connected to the optical fiber 32 drawn out from the light source 30.

The light source 30 includes a semiconductor laser and an optical system for adjusting the light emitted from the semiconductor laser, and provides the laser light to the incidence side of the exposure head 28 of the optical unit 24 using the optical fiber 32.

Figure 2 is a perspective view showing the configuration of an optical unit according to an embodiment of the present invention.

In FIG. 2, the optical unit 24 includes a plurality of exposure heads 28 arranged in a substantially matrix of m rows n columns (for example, 2 rows 5 columns).

The exposure area 34 by the exposure head 28 has a rectangular shape in which the scanning direction is a short side, and a band-shaped exposure completion area 36 is formed in each of the exposure heads 28 on the substrate 16 as the stage 18 moves. ) Is formed.

Further, each of the exposure heads 28 in each row arranged in a line so that the band-shaped exposure completed area 36 is arranged in the direction orthogonal to the scanning direction without a gap is arranged to be out of a predetermined interval in the arrangement direction. For example, a portion that cannot be exposed between the exposure area 34 in the first row and the exposure area 34 in the second row is exposed by the exposure area 34 in the second row.

3 is a perspective view showing a schematic configuration of an exposure head according to an embodiment of the present invention.

In FIG. 3, each of the exposure heads 28 is provided with a correcting lens system 40 for correcting the light emitted from the light exiting end 38 of the optical fiber 32 and exiting the mirror 44, and from the correcting lens system 40. The mirror 44 reflects the light to the digital micro-mirror device 46 (hereinafter referred to as DMD), and the light reflected from the mirror 44 is partially modulated at different reflection angles to form a predetermined pattern. And a condensing lens system 48 for allowing the light beams modulated in the DMD 46 to be imaged on the exposure surface 17 of the substrate 16.

The correction lens system 40 is configured to cause the light emitted from the light exiting end 38 to be uniform, and the light passing through the first correction lens 41 to be condensed on the mirror 44. The second correction lens 42 allows light emitted from the light exiting end 38 to be incident on the mirror 44 with a uniform light amount distribution.

One surface of the mirror 44 is formed as a reflective surface to reflect the light passing through the correction lens system 40 to the DMD 46.

The DMD 46 is a spatial light modulator for modulating the incident light for each pixel according to a desired pattern. The DMD 46 has a plurality of micro mirrors 45 whose L angles are changed on the semiconductor substrate such as silicon. It is a mirror device arranged two-dimensionally in the row M column. By scanning the DMD 46 in a constant direction along the exposure surface 17, a light beam having a predetermined pattern is reflected to the condensing lens system 48.

The condensing lens system 48 includes the first condensing lens 49 and the second condensing lens 50, and the condensing lens system 48 is adjusted by adjusting the distance between the first condensing lens 49 and the second condensing lens 50. The imaging position of the patterned light passing through is adjusted. This condensing lens system 48 allows the light beam modulated by the DMD 46 to be incident on the exposure surface 17 of the substrate 16. As a result, the photosensitive material formed on the exposure surface 17 of the substrate 16 to be exposed is cured or softened.

Figure 4 is an enlarged perspective view showing the configuration of a DMD according to an embodiment of the present invention.

In FIG. 4, the DMD 46 is a mirror device in which a plurality of micro mirrors 45 constituting pixels are arranged on a memory cell 43 in a lattice form, and the surface of the micro mirror 45 has a high reflectance such as aluminum. The material is deposited.

When a digital signal is written to the memory cell 43 of the DMD 46, the micromirror 45 has a predetermined angle (e.g., 12) with respect to the side of the substrate 16 on which the DMD 46 is disposed with the diagonal center as the center. Inclined in the range of °, and the on / off control of each micromirror 45 is controlled by the control part 63 mentioned later, respectively. The light reflected by the micro mirror 45 in the on state is modulated into an exposure state to expose the beam to the exposure surface 17 through the condensing lens system 48, and the light reflected by the micro mirror 45 in the off state. Is modulated to an unexposed state so that the beam is not exposed to the exposure surface 17.

In addition, the DMD 46 is preferably disposed at a slight inclination such that the short side direction forms a predetermined angle with the scanning direction.

5A and 5B are diagrams for describing an operation of a DMD according to an embodiment of the present invention.

5A illustrates a state in which the micromirror 45 is inclined at a constant angle (+ 12 °), and FIG. 5B illustrates a state in which the micromirror 45 is inclined at a constant angle (-12 °) in the off state. Indicates. Therefore, the light beam B incident on the DMD 46 is controlled by the micromirrors 45 by controlling the inclination of the micromirrors 45 in the respective pixels of the DMD 46 according to the control signal of the control unit 63. ) Is reflected in the inclined direction.

6 is a control block diagram of an exposure apparatus according to an embodiment of the present invention. Referring to FIG. 6, the exposure apparatus 10 includes a beam distance measuring unit 26, an input unit 61, and a stage distance measuring unit 62. ), A control unit 63, a stage driver 64, and a mirror driver 66.

The beam distance measuring unit 26 measures the distance between the plurality of exposure beams (for example, three) continuously exposed on the exposure surface 17 to measure the squareness of the stage 18 (the X-axis distance between the exposure beams). And a Y-axis distance between the exposure beams, the camera photographing the images of the plurality of exposure beams and a meter for measuring the distance between the exposure beams in the image of the exposure beam photographed by the camera. The beam distance measuring unit 26 may be fixed to the stage, and the beam distance measuring unit 26 may be provided at a predetermined interval on the gate 22.

The input unit 61 inputs an exposure method (X-axis interval between exposure beams, Y-axis interval between exposure beams, the number of exposure beams, the shape of the exposure beam, etc.) to the control unit 63. That is, the input unit 61 inputs the number of exposure beams projected onto the micromirror of the DMD 46, the X-axis spacing between the exposure beams, and the Y-axis spacing between the exposure beams, to the control unit 63.

The stage distance measuring unit 62 measures the distance that the stage 18 moves (the moving distance in the X-axis direction and the moving distance in the Y-axis direction) and inputs the precision distance measuring instrument (IFM: Interferometer) to the control unit 63. This is a device for measuring by using the interference phenomenon of light.

The control unit 63 controls the overall operation of the exposure apparatus 10, and moves the stage 18 at a predetermined interval so that a plurality of (eg, three) exposure beams are continuously exposed on the exposure surface 17. To measure and correct the squareness of the stage 18.

In addition, the controller 63 calculates an inclination value for measuring the squareness of the stage 18 by using the distance between the plurality of exposure beams, and measures and corrects the squareness of the stage 18 according to the inclination value. To help.

FIG. 7 is a diagram illustrating a spot shape of a beam projected onto a micromirror of a DMD according to an embodiment of the present invention. FIG.

In FIG. 7, the beam projected onto the micromirror 45 of the DMD 46 is projected by turning on or off each micromirror 45 in accordance with a control signal of the control unit 63. At this time, the light reflected by the on-state micromirror 45 is modulated to an exposure state to expose the beam to the exposure surface 17 through the condensing lens system 48, and reflected by the off-state micromirror 45. The light is modulated into an unexposed state so that the beam is not exposed to the exposure surface 17.

One embodiment of the invention uses any three beams B1, B2, B3 projected onto the micromirror 45 of the DMD 46 to measure the squareness of the stage 18, the three beams. X-axis distance (d₁, d₂) and Y-axis distance (d₃) between (B1, B2, B3) is predetermined and can be known through the input unit 61.

FIG. 8 is a diagram illustrating a method of measuring and correcting a squareness of a stage by using a beam continuously exposed to an exposure surface according to an exemplary embodiment of the present invention. Referring to FIG. 8, the operation of the controller 63 is described. It will be described in detail.

The control unit 63 measures the distance between the three exposure beams B1, B2, and B3 measured by the beam distance measuring unit 26 to measure the squareness of the stage 18. The distance between the exposure beams, d₂ ': the distance between the exposure beams of B2 and the exposure beams of B3 is the distance between the three exposure beams inputted by the input unit 61 (d₁: the distance between the exposure beams of B1 and the exposure beams of B2, d₂ : The inclination value [theta] is corrected so that the distance between the exposure beam of B2 and the exposure beam of B3) (i.e., cos [theta] is 1 ([theta] = 0)).

In more detail, the controller 63 calculates an inclination value for measuring the straightness of the stage 18 using the distance between the three exposure beams measured by the beam distance measuring unit 26 below. ] To calculate.

[Equation 1]

cosθ = (d₁ '+ d₂') / (d₁ + d₂)

Here, d \ 'and d2' are actual distances between exposure beams continuously exposed, d₁, d2 is a distance between predetermined exposure beams, and θ is zero.

At this time, correcting the inclination value in the control unit 63 moves the stage 18 at a predetermined angle θ or by using the moving distance of the stage 18 measured by the stage distance measuring unit 62. ) Means to move at regular intervals in the X- and Y-axis directions.

The stage driver 64 drives the stage 18 so that the stage 18 moves the guide 20 at a predetermined interval according to the control signal of the controller 63, and the mirror driver 66 of the controller 63 The DMD 46 is driven on / off to expose a beam of a desired pattern on the exposure surface 17 in accordance with the control signal.

Hereinafter, the perpendicularity measurement and correction process of the exposure apparatus configured as described above will be described.

First, an exposure method (X-axis spacing between exposure beams, Y-axis spacing between exposure beams, the number of exposure beams, the shape of the exposure beam, etc.) for measuring the straightness of the stage 18 is controlled through the input unit 61. 63).

The controller 63 outputs a control signal to the stage driver 64 and the mirror driver 66 according to the exposure method input through the input unit 61.

Accordingly, the stage driver 64 moves the stage 18 at regular intervals in the Y-axis direction according to the control signal of the controller 63 so as to beam on the exposure surface 17 of the substrate 16 seated on the stage 18. To be exposed.

At the same time, the mirror driver 66 drives the DMD 46 according to the control signal of the controller 63 to modulate the light incident through the correcting lens system 40 for each pixel according to a desired pattern to have a constant pattern of light. The beam is reflected by the condenser lens system 48.

And the control part 63 irradiates the exposure surface 17 with three exposure beams B1, B2, and B3 in the form of a spot.

As such, when the three exposure beams B1, B2, and B3 are continuously exposed on the exposure surface 17, the squareness of the stage can be measured. In this embodiment, three exposure beams are measured. The distances d₁ 'and d2' between the points B1, B2, and B3 are measured through the beam distance measuring unit 26 and input to the controller 63.

Then, the controller 63 inputs the distances d₁ ', d₂' between the three exposure beams B1, B2, and B3 measured by the beam distance measuring unit 26 to measure the squareness of the stage 18. The inclination value [theta] is corrected so that the distance (d₁, d2) between the three exposure beams inputted at 61 is obtained.

In more detail, the controller 63 calculates an inclination value for measuring the straightness of the stage 18 using the distance between the three exposure beams measured by the beam distance measuring unit 26 below. ] To calculate.

[Equation 1]

cosθ = (d _n '+ d _{n + 1} ') / (d _n + d _{n + 1} )

Here, d _n ', d _{n + 1} ' are actual distances between exposure beams continuously exposed, d _n , d _{n + 1} are distances between predetermined exposure beams, and θ is zero.

As such, one embodiment of the present invention uses the optical unit 24 already installed in the exposure apparatus 10, so that no additional cost is required, and repeatability and reproducibility for measurement can be obtained, and economical effects can be obtained. More accurate squareness measurement is possible and thus accurate squareness correction can be made.

Meanwhile, in one embodiment of the present invention, the exposure straightness is measured by using any three beams B1 and B2 projected on the DMD 46, but the present invention is not limited thereto. It is a matter of course that the same objects and effects as those of the present invention can be achieved by using three or more arbitrary beams projected on the 46.

1 is a perspective view showing a schematic configuration of an exposure apparatus according to an embodiment of the present invention.

Figure 2 is a perspective view showing the configuration of an optical unit according to an embodiment of the present invention.

3 is a perspective view showing a schematic configuration of an exposure head according to an embodiment of the present invention.

Figure 4 is an enlarged perspective view showing the configuration of a DMD according to an embodiment of the present invention.

5A and 5B are diagrams for describing an operation of a DMD according to an embodiment of the present invention.

6 is a control block diagram of an exposure apparatus according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating a spot shape of a beam projected onto a micromirror of a DMD according to an embodiment of the present invention. FIG.

8 is a view showing a state of measuring and correcting the squareness of the stage by using a beam continuously exposed to the exposure surface according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

16 substrate 17 exposure surface

18 Stage 26 Beam distance measuring unit

46 ... DMD 61 ... Input

62.Stage distance measuring unit 63.Control unit

Claims (8)

A stage for moving the substrate; An optical unit for generating a plurality of beams irradiated onto the substrate; And a control unit for exposing the plurality of beams to an exposure surface of the substrate while moving the stage, and measuring the squareness of the stage using the exposed result. The method of claim 1, It includes a beam distance measuring unit for measuring the distance between the exposed plurality of beams, And the control unit obtains an inclination value for measuring the squareness of the stage by using the distance between the plurality of beams. The exposure apparatus of claim 2, wherein the inclination value is obtained by Equation 1 below. [Equation 1] cosθ = (d _n '+ d _{n + 1} ') / (d _n + d _{n + 1} ) Here, d _n ', d _{n + 1} ' are actual distances between exposure beams continuously exposed, d _n , d _{n + 1} are distances between predetermined exposure beams, and θ is zero. The method of claim 1, wherein the optical unit, And a digital micromirror device for modulating the light emitted from the light source according to the pattern and irradiating the modulated light beam to the exposure surface. The method of claim 1, The stage is moved at regular intervals along the scanning direction, And the controller controls the plurality of beams to be continuously exposed to the exposure surface according to the driving of the stage moved at the predetermined intervals. Move the stage seated on the substrate, Generate and irradiate a plurality of beams on the substrate of the stage, A method of measuring a squareness of an exposure apparatus for exposing the plurality of beams on the exposure surface of the substrate to measure the squareness of the stage. The method of claim 6, Measure a distance between the plurality of exposed beams, And a slope value for measuring a squareness of the stage by using the distance between the plurality of beams. The method of claim 7, wherein the inclination value is obtained by Equation 1 below. [Equation 1] cosθ = (d _n '+ d _{n + 1} ') / (d _n + d _{n + 1} ) Here, d _n ', d _{n + 1} ' are actual distances between exposure beams continuously exposed, d _n , d _{n + 1} are distances between predetermined exposure beams, and θ is zero.

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