X-ray or gamma ray systems or devices – Specific application – Lithography
Reexamination Certificate
1998-12-08
2001-07-03
Porta, David P. (Department: 2882)
X-ray or gamma ray systems or devices
Specific application
Lithography
C378S145000
Reexamination Certificate
active
06256371
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an x-ray illumination device and method using synchrotron radiation or the like and also to an x-ray exposing device and device manufacturing method.
2. Description of the Related Art
FIG. 6
is a configuration diagram illustrating an example of known x-ray exposing devices used for manufacturing semiconductors. A sheet-like SR light
3
is expanded in the Y direction, so that the SR light is cast upon the entirety of the mask
12
. The SR light is not converged with this mirror system, and the light is cast upon the mask without alteration.
Such systems are usually controlled so that the center of the intensity distribution of the SR light in the Y direction is not shifted only in the Y direction as to the reflective surface of the x-ray mirror
19
. This is because the intensity of the x-ray cast upon the mask changes greatly due to Y-directional shift between the SR light and the reflective surface of the x-ray mirror.
Specifically, the Y-directional mirror driving means
16
is controlled by the control means
17
according to the output of the SR light position sensor
18
such that the center of the intensity distribution of the SR light in the Y direction is not relatively shifted from a certain position on the reflective surface of the x-ray mirror.
However, with the above known example, it is difficult to keep the relative positional shift between the x-ray and the reflective surface of the x-ray mirror within a certain range at all necessary frequencies, due to the reasons described below.
First, description shall now be made regarding the relation between the amount of shift between the x-ray and the reflective surface of the x-ray mirror, frequency, and fluctuation of intensity distribution.
The following can be listed as causes which generate relative positional shift between the x-ray and the x-ray mirror, thereby causing irregularities in the intensity distribution of the x-ray cast upon the mask.
(1) Change in the emission position or emission direction of the x-ray due to movement of the electron orbit of the SR.
(2) Relative positional change between the light source and the x-ray mirror due to floor vibrations or vibrations in the x-ray illumination device or SR ring due to floor vibrations.
(3) Deformation of the building (floor on which the device is installed) due to temperature changes.
It is understood that a combination of these factors causes relative vibration of the incident x-ray as to the reflecting surface of the x-ray mirror, thereby causing positional offset. The amount of intensity distribution fluctuation due to this positional shifting is determined by the amplitude (amount of positional shifting) thereof and by the vibration frequency. Of the vibration frequency components of the positional shifting, frequency components which are sufficiently high as to the exposure time for one exposure can be ignored, since the intensity distribution fluctuation thereof is averaged out by the vibration occurring multiple times during the exposure period.
On the other hand, regarding changes at frequencies lower than what can be ignored, positional control must be implemented so that the positional shift between the x-ray and the reflective surface of the x-ray mirror is kept within a certain value. Accordingly, the shorter the exposure time is, the higher the control frequency must be.
However, since x-ray mirrors are usually mounted in a super vacuum, a special mechanism is required, such as a driving mechanism capable of operating in such a super vacuum or a driving force from a drive source positioned in the ambient atmosphere by means of metal bellows or the like. In addition, x-ray mirrors tend to be large and heavy. Accordingly, a large-scale driving device is needed to move the mirror at high frequencies and great amplitudes. At even higher frequencies, the vibrations near the natural vibration of the mirror driving device or supporting system such as the frame induced resonance, which makes controlling difficult in some cases. In light of the above, there are limitations to the extent to which even higher precision can be pursued, in the event that only the known method of just controlling the position of the x-ray mirror is employed.
On the other hand, there is a method wherein the electron orbit of the SR is measured, thereby controlling the position of the electron orbit, i.e., the point of emission, according to the measured values, so as to restrict the positional shift between the x-ray and the x-ray mirror. However, the electron orbit is measured by measurement equipment fixed either to or near the SR ring, so this problem cannot be resolved with respect to floor vibrations or deformation of the building. Accordingly, positional control of the electron orbit must be carried out, and, at the same time, floor vibration for the SR ring must be dealt with. In order to deal with the low-frequency floor vibrations, a vibration-reducing mechanism must be provided to the SR ring. However, taking the weight and size of the SR ring into consideration, it is thought that providing a vibration-reducing mechanism for low frequencies to the SR ring is difficult. In addition, it is quite expensive to vibration-proof the entire building for a range that includes low-frequency vibrations. Even in the event that such a vibration-reducing mechanism happened to be installed, it would not be able to deal with extremely slow positional changes such as deformation of the building due to temperature changes.
Consequently, there is an upper limit to the frequencies for controlling the position or attitude of the x-ray mirror, and there is a lower limit to the frequencies wherein control can be executed since the effects of floor vibrations can be felt even if the electron orbit of the SR ring is controlled. Accordingly, it is difficult to restrict the intensity distribution fluctuations due to shift between the x-ray and the x-ray mirror using only one of these two types of control.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to solve the problems of the known art by providing an x-ray illuminating device wherein the shift of the incident x-rays to the x-ray mirror is greatly reduced, thus enabling x-ray illumination at even higher precision.
It is another object of the present invention to provide an excellent x-ray exposing device and device manufacturing method using the x-ray illuminating device.
That is, according to a first aspect of the present invention, an x-ray illumination device which illuminates an object by reflecting an x-ray irradiated from an emission point with at least one x-ray mirror, comprises: first measuring means for measuring the position of the emission point; first control means for controlling the position of the emission point based on the measurements of the first measuring means; second measuring means for measuring the position of the x-ray near the x-ray mirror; and second control means for controlling the position or the attitude of the x-ray mirror based on the measurements of the second measuring means.
Also, according to a tenth aspect of the present invention, an x-ray exposing device for exposing masks or wafers uses the x-ray illumination device according to the first aspect of the present invention and has means for exposing the masks or wafers.
Also, according to an eleventh aspect of the present invention, an x-ray illumination method for illuminating an object by reflecting an x-ray irradiated from an emission point with at least one x-ray mirror involves controlling the position of the emission point and also controlling the position or the attitude of the x-ray mirror as to the incident x-ray.
Also, according to an thirteenth aspect of the present invention, a device manufacturing method comprises an illuminating step for illuminating masks and wafers, using the x-ray illumination method according to the eleventh aspect of the present invention.
According to a preferred embodiment of the present i
Hasegawa Takayuki
Watanabe Yutaka
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Porta David P.
LandOfFree
X-ray illumination device, x-ray illumination method, and an... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with X-ray illumination device, x-ray illumination method, and an..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-ray illumination device, x-ray illumination method, and an... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2461301