JP2730003B2 - Monitoring method of arc position of discharge lamp - Google Patents

Description

The present invention relates to, for example, a light having a discharge lamp used for exposure for pattern transfer and a condenser mirror for condensing light from the discharge lamp. The present invention relates to a method for monitoring a position of an arc such as a discharge of an irradiation device.

2. Description of the Related Art Various processes such as curing and drying of adhesives, paints, inks, resists, and the like, and exposure of a mask pattern on a semiconductor wafer are performed by light irradiation. A short arc discharge lamp such as a xenon lamp or an ultra-high pressure mercury lamp is used for the light irradiation.

FIG. 4 is an explanatory view showing a schematic configuration of a main part of a light irradiation device using a short arc type discharge lamp, wherein 8 is a lamp body, and this lamp body 8 is a short arc type discharge lamp as a light source. An ultra-high pressure mercury lamp (hereinafter referred to as a lamp) 1, an elliptical converging mirror 2, which condenses the light of the lamp 1, a plane reflecting mirror 3, an integrator lens 4, and a condenser lens 6, the light passing through the condenser lens 6 The light is irradiated on the irradiation surface 9. Reference numeral 7 denotes a position adjusting mechanism for the lamp 1. At the time of mounting the lamp 1, the lamp 1
And the light from the lamp 1 through the elliptical condenser mirror 2 is reflected by the reflector 3 to form an integrator lens 4 (which is located at the second focal point of the elliptical condenser mirror 2). Position).

Therefore, it is necessary to install the lamp 1 so that the center of the arc is located at the first focal point of the elliptical condenser mirror 2. Otherwise, the light from the lamp 1 cannot be efficiently collected by the integrator lens 4 and the irradiation surface 9 cannot be uniformly irradiated with the light with high illuminance.

Therefore, it is necessary to adjust the center of the arc of the lamp 1 so as to be at the first focal point of the elliptical focusing mirror 2.

When adjusting the lamp 1, after removing the upper lid of the lamp body 8,
An operator puts his hand in the lamp body 8 and operates the position adjustment mechanism 7 to move the lamp 1 in the height direction and the vertical and horizontal directions on the plane. At that time, the position of the lamp 1 is
The following two methods have been considered as a method for confirming whether or not the discharge lamp is accurately positioned at the desired position, that is, a conventional method for monitoring the arc position of a discharge lamp.

As shown in FIG. 4, a light receiver of an irradiation monitor 10 is provided on an irradiation surface 9.
With the position 10a, the position of the lamp 1 is monitored by monitoring the illuminance distribution of the irradiation surface 9 while adjusting the position of the lamp 1 by the position adjusting mechanism 7, and the position of the arc of the lamp 1 is known. Then, when the illuminance is maximum and the illuminance distribution becomes uniform, it can be confirmed that the arc is at the position of the first focal point of the elliptical converging mirror 2.

As shown in FIG. 5, the arc image of the lamp 1 is converted to the holes 2a and 2b of the elliptical converging mirror 2 and the lenses 11a, 12a, 14a, 15a and 11
b, 12b, 14b, 15b, and a mirror system for turning back 13a and 13b, monitor while enlarging and forming an image on two screens 16a (X-axis, Z-axis) and 16b with a crosshair formed in the center, By operating the position adjusting mechanism of the lamp 1, the arc is imaged at the center of the two screens with the crosshairs, and the arc is positioned at the first focal point.

[Problems to be Solved by the Invention] As described above, in the conventional method for monitoring the position of the arc of a discharge lamp, in the above-described method, since the irradiation surface is inside the mechanism structure of the apparatus, etc. It is sometimes difficult to monitor the illuminated surface because the vessel may not be placed directly for irradiation.

Even if the receiver can be placed on the irradiation surface, adjust the position while looking at the receiver because the operating part of the position adjustment mechanism of the discharge lamp and the irradiation surface are far apart. Is difficult.

In the above method, the arc image is usually about 3 mm.
Since it is difficult to project the image on the screen at the same magnification and visually monitor it, it is necessary to magnify and form the arc image.

Therefore, in order to magnify and form an image of the arc, a large number of lenses and a mirror for turning back are required, and furthermore, the optical path length for each lens becomes large, and the device becomes large-scale. However, there is a problem that adjustment at the time of assembly by using the lens or mirror is difficult.

The present invention has been made in order to solve such a conventional problem, and can be monitored without placing a light receiver on an irradiation surface, and it is not necessary to form an enlarged image of an arc. It is an object of the present invention to provide a method of monitoring the position of an arc of a discharge lamp which can reduce the number of mirrors and mirrors.

Means for Solving the Problems In order to achieve the above object, a method for monitoring the position of an arc of a discharge lamp according to the present invention is provided by a photoelectric conversion element having a segment arranged at a predetermined optical position and divided into a plurality of segments. An image of the arc of the discharge lamp is formed on the incident surface by an imaging lens, and monitoring is performed by comparing electric signals from each segment.

[Operation] In the above method, the position of the arc is electrically monitored by comparing the electric signals from each segment.
It is not necessary to visually check the screen or place a light receiver on the irradiation surface as in the related art.

Embodiment FIG. 1 is an explanatory view of an embodiment of a monitoring method according to the present invention, and FIGS. 2 (a) and 2 (b) are explanatory views of incident surfaces of two photoelectric conversion elements of FIG. . FIG. 3 is a circuit block diagram for explaining the photoelectric conversion element, the signal processing circuit, and the display unit used in FIG. 1 in terms of an electric circuit.

1 and 2, the arc image of the lamp 1 is
First, in the X-axis and Z-axis directions, an image is formed on the photoelectric conversion element 20a from the hole 2a of the elliptical condenser mirror 2 via the pinhole plate 17a and the imaging lens 18a.

Similarly, in the Y-axis direction,
An image is formed on the photoelectric conversion element 20b from 2b via a pinhole plate 17b and an imaging lens 18b.

That is, the pinhole plate 17a and the imaging lens 18a, the pinhole plate 17b and the imaging lens 18b have the first focal point of the elliptical converging mirror 2 as the object point, and the origin 0 of the incident surface of the photoelectric conversion elements 20a and 20b.
(Described later) are arranged as image points.

In the present embodiment, the photoelectric conversion elements 20a and 20b use photodiodes, and the incident surface thereof is divided into four segments D ₁ and D 4 electrically insulated from each other as shown in FIG.
_2, D _3, D ₄ and _{D 5, D 6, D 7} , D 8, made of. Accordingly, the photoelectric conversion elements 20a, 20b are segments _{D 1, D 2, D 3} , D 4 and _{D 5, D 6, D 7} , D 8
Photodiodes D ₁₀ , D ₂₀ , D ₃₀ , D ₄₀ and D
₅₀ , D ₆₀ , D ₇₀ , D ₈₀
The origin 0 of each of the incident surfaces a and 20b is located on each optical axis. Each of the incident surfaces of the photoelectric conversion elements 20a and 20b is set to be perpendicular to each optical axis. Such a configuration of the photoelectric conversion elements 20a, with respect to 20b, when the arc of the lamp 1 is not correctly positioned at the first focal point of the elliptical condensing mirror 2, each of the segments D ₁ and the D _3, D ₂ the difference in the light striking the D ₄ or D ₅ and D ₇ will be occurs, the difference in the light is converted to the photocurrent is converted by the signal processing circuit 21 into a voltage, each Hotodaiado D ₁₀ and D _30, D in the ₂₀ and D ₄₀ or D ₅₀ and D _70, the difference voltage based on the difference between the photocurrent is generated, monitored and displayed on the display unit 22 compares the difference. Conversely, when the arc is correctly positioned at the first focal point, there is no difference between the current and the voltage, and therefore, the display unit 22 displays 0 to that effect.

In the above embodiment, the pinhole plates 17a, 17b have the holes 2a,
The amount of light from 2b is reduced so that too strong light does not enter according to the sensitivity of the photoelectric conversion elements 20a and 20b.

Incidentally, in this embodiment, as not relevant with regard since the photoelectric conversion element 20b is monitored only the displacement of the arc relative to the Y-axis direction segments D ₆ and D ₈ (photodiode D _60, D ₈₀₎ Are dealing.

The light of the arc is converted to a photoelectric conversion element using FIG.
Processing after photoelectric conversion in 20a and 20b will be described.

From arc first focus of the elliptical condensing mirror 2, for example if the shift even slightly in the X-axis direction, a difference occurs in the current of the photodiode D ₁₀ and D _30, the current - converted by the voltage conversion circuit 211 into a voltage, An output is provided to the comparison circuit 217, and this output causes the hand of the voltmeter at the zero center of the display unit 22a in the X-axis direction to swing to the left or right, thereby displaying the positional deviation. Similarly,
Display unit for displacement in the Y-axis direction and Z-axis direction
Since it is displayed on 22c and 22b, the position deviation is adjusted while monitoring it. Also, the arc of the lamp is X axis, Y axis, Z axis.
When correctly positioned at the position of the first focal point of the elliptical converging mirror with respect to each direction of the axis, the hands of the voltmeter at the zero center in each of the display units in the X-axis direction, the Y-axis direction, and the Z-axis direction are zero. Of course. The display unit may be a normal zero-left display unit, but a zero-center display unit is preferable because the direction of the deviation can be determined. Further, another light source conversion element and an imaging lens are provided, and X
The axis, the Y axis, and the Z axis may be independently monitored.

[Effects of the Invention] As described above, the method of monitoring the arc position of the discharge lamp according to the present invention provides the discharge lamp on the incident surface of the photoelectric conversion element having a plurality of segments arranged at predetermined optical positions. The image of the arc is formed by the image forming lens and the monitoring is performed by comparing the electric signals from the respective segments. Therefore, there is no need to directly place the light receiver of the illuminance monitor on the irradiation surface, and furthermore, the magnified image is formed. Since there is no need for imaging, the number of lenses and mirrors can be reduced. As a result, the device can be reduced in size and can be easily adjusted during assembly.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of a monitoring method according to the present invention, and FIG.
FIGS. 2A and 2B are explanatory views of the incident surfaces of the two photoelectric conversion elements shown in FIG. 1, and FIG. 3 is a circuit diagram of the photoelectric conversion element, signal processing circuit and display unit used in FIG. FIG. 4 is an explanatory diagram showing a schematic configuration of a main part of a light irradiation device using a short arc type discharge lamp, and FIG. 5 is an explanatory diagram of a conventional arc monitoring method. is there. In the figure. 1: lamp, 2: elliptical converging mirror 2a, 2b: hole 7: position adjusting mechanism of discharge lamp 18a, 18b: imaging lens 20a, 20b: photoelectric conversion element 21: signal processing circuit, 22: display unit

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-109461 (JP, A) JP-A-58-195825 (JP, A)

Claims (1)

(57) [Claims] An image of an arc of a discharge lamp is formed by an imaging lens on an incident surface of a photoelectric conversion element having a plurality of divided segments arranged at predetermined optical positions. A method for monitoring the arc position of a discharge lamp, wherein the monitoring is performed by comparing signals.