JPH0555106A - Exposure controller - Google Patents

Abstract

PURPOSE:To make a large dynamic-range and high-accuracy exposure control possible and thereby to increase the throughput and exposure accuracy of an aligner. CONSTITUTION:In an exposure controller which has a light source 1 to give exposure light to a mask 5 and a shutter 2 installed between the light source 1 and the mask 5 and which is used in an aligner for projecting a pattern of the mask 5 on a substrate to be exposed 6, an exposure setting device for setting a desired exposure, an exposure integrating device 4 installed between the shutter and the mask, first exposure controlling devices 9, 10 which close the shutter according to the integrated exposure value and the exposure set by the exposure setting device, and a light source illuminance measuring device 3 located between the light source and the shutter are installed. The exposure controller is also provided with second exposure controlling devices 7, 10 which change a shutter driving speed according to the measured illuminance and the set exposure and a switching device 8 which switches from the first controlling devices to the second ones or from the second ones to the first ones according to the set exposure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure amount control device used in an exposure apparatus such as a semiconductor exposure apparatus.

[0002]

2. Description of the Related Art Conventionally, an exposure amount control device for an exposure apparatus is shown in FIG.
Was configured like. In the figure, 5 is a mask,
Reference numeral 1 is a light source for giving exposure light to the mask 5, 6 is a substrate to be exposed such as a semiconductor wafer for projecting and exposing the pattern of the mask 5, and an exposure shutter 2 is provided between the light source 1 and the mask 5.
Are arranged. Reference numeral 4 denotes a light intensity detector, 9 denotes an integrated exposure amount based on the output of the light intensity detector 4, and an integrated exposure amount determiner for generating a determination output when the integrated exposure amount reaches a predetermined value, 10 Is an exposure shutter drive circuit that opens the exposure shutter 2 based on an exposure command from a CPU (not shown) and closes the exposure shutter 2 based on the determination output of the integrated exposure amount determination device 9. The exposure amount control device includes a light intensity detector 4, an integrated exposure amount determiner 9, and an exposure shutter drive circuit 10.

The exposure control device shown in FIG. 2 has a light intensity detector 4
Based on the obtained information, the exposure shutter 2 is driven to perform exposure with a predetermined exposure amount. FIG. 3 shows an example of the exposure shutter and how it is driven. The exposure shutter 2 is
Normally, the shutter is closed (closed) as shown in FIG. 3A and blocks the illumination light 31 emitted from the exposure light source 1 (FIG. 2). However, when the exposure command is issued, the shutter blades 32 are provided. Rotates to enter the shutter open state shown in FIG. When the integrated exposure amount determination output is generated, the shutter blade 32 further rotates and the shutter blade 32 is rotated as shown in FIG.
The same shutter close (close) as in FIG. 3A shown in FIG.
Return to the state of.

FIG. 4 shows the relationship between the shutter drive speed and the time when the shutter is opened / closed (open / close). The relationship between time and illuminance at this time is shown in FIG.

In FIG. 5, the area of the trapezoid is the exposure amount.
This value is obtained by integrating the information of the light intensity detector 4 (FIG. 2).

The exposure controller of FIG. 2 assumes that the areas of the rising portion (a) and the falling portion (b) of the illuminance shown in FIG. 5 are almost equal, and the exposure amount after the shutter is opened is (the set exposure amount). -The shutter is closed when the exposure amount reaches the rising portion (a)), and the exposure is performed so that the exposure amount becomes the set exposure amount.

In this exposure control apparatus, as shown in FIG.
After the shutter is opened, the rest time Topen is set to Top
The minimum exposure amount, that is, the shortest exposure time is set when en = 0 (see FIGS. 6 and 7).

[0008]

By the way, as the power of the exposure light source is increased, the throughput is expected to be improved by shortening the exposure time. However, in the conventional exposure control device, the throughput is improved because of the limitation of the shortest exposure time. Is an obstacle.

On the other hand, in order to perform short-time exposure, an exposure method by non-stop shutter drive by shutter speed control can be considered. Even if the shutter speed control is performed by the conventional integrated exposure amount feedback method, the illuminance of the light source is It is difficult to obtain an optimum drive pattern according to the above, and unevenness in exposure occurs. On the other hand, when performing long-time exposure, the exposure method using the non-stop shutter drive by controlling the shutter speed is significantly inferior to the conventional method in terms of throughput and accuracy.

The present invention has been made in view of the problems in the above-mentioned conventional example, and it is possible to perform the exposure amount control with a large dynamic range and high accuracy, and thus it is effective for improving the throughput and the exposure accuracy of the exposure apparatus. An object is to provide an exposure amount control device.

[0011]

In order to achieve the above object, the present invention comprises a light source for giving exposure light to a mask, and a shutter arranged between the light source and the mask, and the pattern of the mask is exposed. In an exposure amount control device of an exposure device for projecting onto a substrate, an exposure amount setting means for setting a desired exposure amount, an exposure amount integrating means arranged between a shutter and a mask, the exposure amount integrated value and the above-mentioned First exposure amount control means for performing a shutter closing operation according to the set exposure amount set by the exposure amount setting means, light source illuminance measuring means arranged between the light source and the shutter, the illuminance measurement value and the set exposure. It is provided with a second exposure amount control means for changing the shutter drive speed according to the amount and a switching means for switching between the first and second control means according to the set exposure amount.

[0012]

According to the above structure, a non-stop shutter by shutter speed control suitable for short-time exposure is provided in contrast to a conventional exposure amount control apparatus having an integrated exposure amount feedback type exposure amount control system suitable for long-time exposure. A drive type control system and a switching means for selecting one of the two control systems according to the exposure amount are provided.

To give a specific example, in the present invention, in order to perform the non-stop shutter drive, a new light intensity where the relationship with the light intensity detector 4 is known in the preceding stage of the shutter as shown in FIG. A detector 3 was provided. Before the shutter is driven, the information of the light intensity detector 3 can be used to determine the optimum shutter drive pattern and speed according to the set exposure amount.

However, since the above-mentioned exposure amount control method is an open loop control which is characterized in that short-time exposure can be performed, the conventional control method based on the integrated value of exposure amount feedback is superior when performing long-time exposure. There is.

Therefore, there are two control methods depending on the exposure time such as the long time mode and the short time mode, and the mode is automatically selected according to the exposure amount based on the information of the light intensity detector 3.

As a result, a wide range of exposure conditions can be dealt with, and throughput and exposure accuracy can be improved.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is an exposure light source, 2 is an exposure shutter, 3 and 4 are light intensity detectors, 5 is a mask, 6 is a wafer, 7 is a shutter drive speed calculator, 8 is an exposure mode determination device, and 9 is integrated exposure. The quantity determiner 10 is an exposure shutter drive circuit. The exposure light source 1, the exposure shutter 2, the light intensity detector 4, the mask 5, the wafer 6, the integrated exposure amount determiner 9 and the exposure shutter drive circuit 10 are common to the conventional example shown in FIG. The device 3, the shutter drive speed calculator 7, and the exposure mode determiner 8 are newly added according to the present invention.

In FIG. 1, the illumination light emitted from the exposure light source 1 is blocked by the exposure shutter 2. Exposure shutter 2
The illumination light that has opened and passed illuminates the mask 5 to print the pattern on the wafer 6. The light intensity detectors 3 and 4 detect the light intensity before and after the exposure shutter 2.

The exposure time is calculated by the exposure mode determination unit 8 from the set exposure amount and the light source illuminance information of the light intensity detector 3 to determine whether to use the long-time exposure mode or the short-time exposure mode.

In the long-time exposure mode, after the shutter is opened, the information of the light intensity detector 4 is integrated by the integrated exposure amount determiner 9, and when the predetermined exposure amount is reached, the exposure shutter drive circuit 1
The shutter 2 is closed by 0 (see FIGS. 4 and 5).

In the short-time exposure mode, the shutter drive speed calculator 7 obtains a shutter drive speed pattern corresponding to the set exposure amount from the information of the light intensity detector 3 for exposure. FIG. 8 shows the relationship between the shutter drive speed and time at this time.
9 shows the relationship between illuminance and time. Conventionally, the exposure time and the exposure amount can be shortened because the acceleration can be performed during the time of deceleration due to the standstill after the shutter is opened. The exposure amount is controlled by changing the acceleration / deceleration amount as shown in FIGS. 10 and 11, or by the trapezoidal drive by the maximum speed limitation as shown in FIGS.

[0023]

As described above, according to the present invention, it is possible to perform exposure amount control with a large dynamic range and high accuracy.

Further, since the shortest exposure time is greatly shortened, the throughput can be improved as the power of the exposure light source is increased.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an exposure amount control apparatus for carrying out the present invention.

FIG. 2 is a conceptual diagram of a conventional exposure amount control apparatus.

FIG. 3 is an example of an exposure shutter and its operation.

FIG. 4 is a graph showing the relationship between the conventional shutter speed and time during exposure.

5 is a graph showing the relationship between exposure illuminance and time corresponding to FIG.

FIG. 6 is a graph showing the relationship between conventional shutter speed and time during exposure.

7 is a graph showing the relationship between exposure illuminance and time corresponding to FIG.

FIG. 8 is a graph showing the relationship between shutter speed and time in the present invention during exposure.

9 is a graph showing the relationship between exposure illuminance and time corresponding to FIG.

FIG. 10 is a graph showing the relationship between shutter speed and time in the present invention during exposure.

11 is a graph showing the relationship between exposure illuminance and time corresponding to FIG.

FIG. 12 is a graph showing the relationship between shutter speed and time in the present invention during exposure.

13 is a graph showing the relationship between exposure illuminance and time corresponding to FIG.

[Explanation of symbols]

1: exposure light source, 2: exposure shutter, 3, 4: light intensity detector, 5: mask, 6: wafer, 7: shutter drive speed calculator, 8: exposure mode determiner, 9: integrated exposure amount determiner,
10: exposure shutter drive circuit

Claims (1)

[Claims] 1. An exposure amount control apparatus for an exposure apparatus, comprising: a light source for giving exposure light to a mask; and a shutter arranged between the light source and the mask, the exposure amount control apparatus for an exposure apparatus projecting a pattern of the mask onto a substrate to be exposed. Exposure amount setting means for setting the exposure amount, exposure amount integrating means arranged between the shutter and the mask, and the exposure amount integrating value and the set exposure amount set by the exposure amount setting means. First exposure amount control means for performing a shutter closing operation, light source illuminance measuring means arranged between the light source and the shutter, and second exposure for changing the shutter drive speed according to the illuminance measurement value and the set exposure amount. An exposure amount control device comprising: an amount control device; and a switching device for switching between the first and second control devices according to the set exposure amount.