JPH04155295A - Synchrotoron radiation exposure - Google Patents

Abstract

PURPOSE:To make an oscillating mechanism unnecessary and simplify a structure by arranging an X-rays slanting incidence mirror in a light takeout line, making this reflect SOR light and taking out from the said light takeout line. CONSTITUTION:A control device 40 controls a deflecting electromagnet power supply 38 in exposing time and fluctuates an exciting current value round a regular value with a period about a second. The electron beam energy within a storage ring 22 changes with a constant slope by this. The reflectivity of an X-rays slanting incidence mirror 30 to the SOR light 29 changes when the electron beam energy is changed. The light quantity distribution of the SOR light 29 in the vertical direction fluctuates on an X-rays photomask substrate 34 so as to show in the diagram by this. Therefore, the SOR light 29 is emitted without unevenness in the vertical direction to the X-rays photomask substrate 34 by fluctuating the electron beam energy once from the minimum value to the maximum value or from the maximum value to the minimum value and the exposure of one semiconductor wafer 36 is finished.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an exposure method using SOR light (synchrotron radiation light), and the present invention relates to an exposure method using SOR light (synchrotron radiation light). It is designed to be able to swing vertically.

C. Prior Art] SOR light is a powerful light beam such as X-rays emitted from the deflection position of an electron beam orbiting a storage ring in a synchrotron, and is applied to exposure light sources in the VLSI manufacturing process. is expected.

Exposure using SOR light is generally performed by guiding the SOR light from the electron beam deflection position of a synchrotron to a light extraction line branched in the tangential direction, and then emitting it from a window provided at the end of this light extraction line. This is carried out by irradiating the semiconductor wafer through the substrate of a photomask for LSI exposure. In this case, since the SOR light has a wide width in the horizontal direction but a narrow width in the vertical direction, the exposure area in the vertical direction must be ensured by swinging the SOR light in the vertical direction.

Conventionally, as a method for vertically swaying SOR light, a so-called mirror swing method is used in which an X-ray oblique incidence mirror is placed in the light extraction line with its reflecting surface facing diagonally upward or diagonally downward. The SOR light was swung in the vertical direction by swinging the input mirror around a rotation axis that was disposed horizontally and perpendicular to the SOR light optical axis.

[Problem to be solved by the invention]

The mirror rocking method requires a rocking mechanism to rock the oblique incidence mirror, which increases costs and requires regular maintenance and inspection to deal with deviations in rocking angle due to changes over time. etc. were needed.

The present invention aims to solve the drawbacks of the conventional techniques and provide an SOR light exposure method that can swing the SOR light in the vertical direction without mechanical movement of a swinging mechanism or the like. .

[Means to solve the problem]

This invention branches a light extraction line in the tangential direction from the deflection position of the storage ring around which the electron beam is orbiting, and extracts the SOR light from this light extraction line.
When exposing an object to light, an X-ray oblique incidence mirror is arranged in the light extraction line to reflect the SOR light and extract it from the light extraction line, and also to absorb the electron beam energy in the storage ring. The feature is that exposure is performed while varying within a predetermined range.

[For production]

According to this invention, when the electron beam energy is varied, the spectrum of the SOR light changes, and the apparent reflectance of the X-ray oblique incidence mirror also changes, which causes the light intensity distribution of the SOR light to be swayed in the vertical direction. , the SOR light can be oscillated in the vertical direction.

According to this, the X-ray oblique incidence mirror can remain fixed, eliminating the need for a swinging mechanism, simplifying the configuration, and
Maintenance inspection, etc. can be made unnecessary.

〔Example〕

An embodiment of this invention will be described below.

FIG. 1 shows an outline of an SOR optical device to which the present invention is applied.

In the SOR optical device 1, an electron generator (electron gun, etc.) 1
The electron beam generated at
2, the beam is accelerated to near the speed of light, is deflected by the deflection electromagnet 16 of the beam transport section 14, and enters the storage ring 22 of the synchrotron via the inflector 18. The electron beam incident on the storage ring 22 is energized by the high frequency acceleration cavity 21, focused by the focusing electromagnet 23, deflected by the deflection electromagnet 24, and continues to circulate within the vacuum duct 22. When deflected by the deflection electromagnet 24, the SOROR beam 9 is emitted in the tangential direction and is emitted through the extraction line 26, sent to the exposure device 28, and used as an X-ray light source for exposure for producing LSI circuits.

In the light extraction line 26, as shown in FIG.
A line oblique incidence mirror 30 is fixedly arranged. The X-ray oblique incidence mirror 30 is configured as a plane mirror or a cylindrical mirror made of SiC or the like, and has a reflecting surface facing diagonally downward.
The incident SOROR beam is combined and bent slightly downward.

Beryllium window 3 provided at the end of the SOROR beam combination 9 light extraction line 26 reflected by the X-ray oblique incidence mirror 30
The X-rays are emitted through X-ray photomask substrate 34 and irradiated onto semiconductor wafer 36 for exposure.

In FIG. 1, the coils of the four bending electromagnets 24 are connected in series, and an excitation current is supplied from a bending electromagnet power supply 38, so that the four bending electromagnets 24 are excited to the same amount of excitation. The magnitude of this excitation current corresponds to the energy value of the electron beam circulating within the storage ring 22. That is, when the excitation current value is small, the electron beam energy value also becomes small, and when the excitation current value is large, the electron beam energy value also becomes large. Therefore, by controlling this excitation current value, the electron beam energy can be varied.

The control device 40 controls the bending electromagnet power supply 38 during exposure to vary the excitation current value around a constant full value at a cycle of about 1 second. As a result, the electron beam energy within the storage ring 22 changes at a constant gradient as shown in FIG. Assuming that the steady-state value is 800 M e V, the variation width is set to, for example, ± several M e V.

When the electron beam energy is changed, the spectrum of the SOR light 29 changes, and the apparent reflectance of the X-ray oblique incidence mirror 30 with respect to the SOR light 29 changes. This results in X
The light intensity distribution of the SOR light 29 in the vertical direction on the line photomask substrate 34 varies as shown in FIG. Therefore, by once changing the electron beam energy from the minimum value to the maximum value or from the maximum value to the minimum value, the SOR light 29 is
The line photomask substrate 34 is irradiated evenly in the vertical direction, and the exposure of one semiconductor wafer 36 is completed.

[Example of change]

In the embodiment described above, the electron beam energy is varied only once in one direction for each exposure of one sheet, but it is also possible to expose one sheet by making one reciprocation or multiple reciprocations.

〔Effect of the invention〕

As explained above, according to the present invention, when the electron beam energy is varied, the spectrum of the SOR light changes, and the apparent reflectance of the X-ray oblique incidence mirror changes, thereby changing the light intensity distribution of the SOR light. swung vertically, S
The OR light can be oscillated in the vertical direction. Therefore, the X-ray oblique incidence mirror can remain fixed, eliminating the need for a swinging mechanism, simplifying the configuration, and eliminating the need for maintenance and inspection.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention, and is a plan view showing an outline of an SOR optical device. FIG. 2 is a longitudinal sectional view showing the internal structure of the light extraction line 26 and exposure device 28 in FIG. 1. FIG. 3 is a waveform diagram showing an example of the fluctuation state of the electron beam energy according to the present invention. Figure 4 shows the
3 is a diagram showing a vertical SOROR light quantity distribution movement on a line photomask substrate 34. FIG. 22... Storage ring, 26... Light extraction line, 2
9...SOR light, 30...X-ray oblique incidence mirror, 36...
. . . Semiconductor wafer (exposure target), 40-. Control device for bending electromagnet power supply. Applicant Ishikawajima Harima Heavy Industries Co., Ltd. Figure 3 Figure 4

Claims (1)

[Claims] In the case where a light extraction line is branched in the tangential direction from the deflection position of the storage ring around which the electron beam is orbiting, and the SOR light is extracted from this light extraction line to expose the exposure target, there is a SOR characterized in that an X-ray oblique incidence mirror is arranged to reflect the SOR light and take it out from the light extraction line, and to perform exposure while varying the electron beam energy in the storage ring within a predetermined range. Light exposure method.