JPS607722A - X-ray exposure device - Google Patents

Abstract

PURPOSE:To contrive to enhance uniformity of X-ray intensity distribution by a method wherein a means to measure X-ray intensity distribution at an exposing surface, and a means to transfer an exposing substance conforming to the X-ray intensity distribution thereof are provided. CONSTITUTION:An exposing substance 2 is put upon a transferably movable base 1. Detectors 3 of the plural number of pieces are arranged symmetrically centering the mechanically central axis of an X-ray source at the periphery of the movable base 1 thereof as an X-ray (b) intensity distibution measuring means. At the device thereof, when X-ray intensity distribution at an exposing surface put on with the substance 2 becomes ununiformly, differences are generated to detection outputs of the respective detectors 3. When the shape of the relative intensity distribution curve of the X-ray mentioned above is known, the movable base 1 is transferred, the movable base 1 is so transferred as to make the central position of X-ray intensity distribution and the central position of the substance 2 to coincide, and controlled as to make X-ray intensity distribution to become symmetrically centering the central position of the substance 2.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an X-ray exposure apparatus used for transferring semiconductor integrated circuit patterns, etc., and is particularly capable of exposing an object to X-rays with a uniform intensity distribution. The present invention relates to an X-ray exposure device.

fb) Background of the technology In the manufacturing of semiconductor integrated circuits, as the degree of integration of circuits increases, it becomes necessary to form finer patterns. Development of the device and the X-ray source for its light source is progressing. As the above-mentioned X-ray source, a plasma-type X-ray source that utilizes X-rays generated from plasma generated by electric discharge is currently considered to be promising. This is because higher efficiency can be obtained than conventional electron impact type X-ray sources, and among these, gas injection type plasma X-ray sources that use gas discharge are attracting attention for their long life.

(C) Prior art and problems In exposure equipment that uses a gas injection type plasma Ex-7 source, the position of the generated plasma may vary due to equipment assembly accuracy or changes in the electrode surface during long-term use. The radiation source may be deviated from the mechanical center axis, and as a result, the intensity distribution of the X-rays at the exposure surface becomes asymmetrical with respect to the mechanical center axis of the source. That is, the X-ray intensity distribution on the exposed surface becomes non-uniform.

However, in conventional X-ray exposure equipment of this type, the object to be exposed is fixedly arranged with respect to the mechanical center axis of the radiation source, which resulted in the non-uniformity of the intensity distribution as described above. In some cases, there is no means to correct this, and the exposure dose distribution to the exposed object becomes non-uniform, resulting in disadvantages such as the inability to obtain desired pattern precision.

(d1) Purpose of the Invention The object of the present invention is to provide an X-ray exposure apparatus that eliminates the drawbacks of the conventional X-ray exposure apparatus described above, enables uniform exposure, and is capable of highly accurate pattern transfer.

te+ Structure of the Invention The present invention provides an X-ray exposure apparatus using a gas-injected plasma X-ray source, which includes means for measuring an X-ray intensity distribution on an exposure surface and means for moving an object to be exposed based on the X-ray intensity distribution. In this case, a plurality of X-ray detectors are used as means for measuring the X-ray intensity, and these are arranged either on the exposure surface or between the X-ray source and the exposure surface.

Examples of ff1 invention Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, an object to be exposed 2, such as a silicon wafer coated with a resist, is placed on a movable table l that can be moved in two dimensions, for example, in response to an external control signal. A mask (not shown; the same applies hereinafter) having openings in a predetermined pattern is attached to the surface of the object 2 to be exposed. Further, around the movable table 1, a detector 3 such as a semiconductor detector is installed as an X-ray intensity distribution measuring means.
are arranged symmetrically about the mechanical central axis of the radiation source (specifically, the central axis of an aperture 5 provided in the anode 4, which will be described later). In the case of this embodiment, four pieces are arranged as shown in the plan view of the same figure (B).

The main parts of the X-ray source, as shown in the side view of FIG. After evacuating the inside of the vacuum container 8, the high-speed valve 7 is opened and closed at high speed to eject gas from the nozzle 9 provided at the tip of the cathode 6, and in synchronization with the gas ejection, the discharge switch 10 is activated. A high voltage charged in a discharging capacitor 11 is applied between the anode 4 and the cathode 6 by opening and closing to cause discharge, and plasma 12 is generated in the opening 5 between the anode 4 and the cathode 6. As a result, the X-rays generated by the plasma 12 are irradiated onto the object 2 to be exposed through the opening 5.

In the above case, if there is misalignment between the center of the movable base 1, the central axis of the opening 5, and the central axis of the cathode 6, or if the periphery of the opening 5 or the surface of the cathode 6 is deformed due to repeated discharge over a long period of time. If the plasma 1 is deposited on the central axis of the aperture 5,
2 is not generated, and as a result, the X-ray intensity distribution in the exposed object 2 is not symmetrical with respect to the central axis of the source.

This asymmetry makes the intensity distribution on the exposed surface on which the exposed object 2 is placed non-uniform, causing a difference in the detection outputs of the respective detectors 3. This situation is shown in FIG.

Figure (A) shows a case where the X-ray intensity in the exposed object 2 is distributed symmetrically around the mechanical central axis of the radiation source, and the detection by two detectors located symmetrically with respect to the central axis is shown. The outputs (11 and I2) are equal. on the other hand,
Figure (B) shows a case where the X-ray intensity is not distributed symmetrically with respect to the mechanical center axis of the radiation source, and for example, there is a difference between the detection outputs (II and 12) of two detectors similar to the above. ing. Assuming that it is known that the relative intensity distribution curve of X-rays is shaped like the broken line in the figure, the center position of this intensity distribution is Cx, and on the other hand,
Since the center position of the object 2 to be exposed is Cs, the movable table 1 is moved so that Cs coincides with Cx, and the X-ray intensity distribution is controlled to be symmetrical about Cs.

FIG. 3 shows an example in which the detectors 3 are arranged on the movable table 1 symmetrically with respect to the center position of the object to be exposed 2. With this configuration, the detection outputs (11 and 12) as shown in FIG.
), it is sufficient to simply move the movable table 1 so that 11 and I2 become equal, and there is no need to assume the relative intensity distribution curve of X-rays as described above, and the intensity distribution for the object 2 to be exposed can be controlled more accurately.

FIG. 4 shows a case where a detector 3 is provided between an object to be exposed 2 and an X-ray source (simply an anode 4), and the detector 3 is provided with an aperture 13 having a sufficiently large diameter, for example. It is arranged on an annular support base 14. Furthermore, a movable shank 15 is provided between the annular support base 14 and the object to be exposed 2.
is provided. According to the configuration shown in the figure, if the relative positional relationship between the center of the movable base 1 and the center of the annular support base 14 is determined in advance, the X-ray Measure the intensity distribution with the detector 3 without irradiating the object, and control the movement of the movable table 1 based on the detection output (11 and I2) similar to that shown in FIG. Exposure can be performed by opening the movable shutter 15 while aligning the center of the intensity distribution. In other words, it is now possible to perform exposure under adjusted exposure conditions with a uniform intensity distribution.
As in the other embodiments above, position adjustment (
Since no intensity distribution control is performed, the uniformity of the total exposure X-ray dose can be further improved.

(g) Effects of the Invention According to the present invention, in an X-ray exposure apparatus using a gas-injected plasma Enx-ray source, the uniformity of the X-ray intensity distribution on the exposure surface is improved, making it possible to perform exposure with higher precision. This has the effect of making it possible to provide an X-ray exposure apparatus suitable for exposing highly integrated circuit patterns and the like.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic concept of the X-ray exposure apparatus according to the present invention, FIG. 2 is a diagram for explaining the X-ray intensity distribution and uniformization control, and FIGS. 3 and 4 are diagrams showing other embodiments of the present invention. It is a figure which shows an example. In the figure, 1 is a movable table, 2 is an object to be exposed, 3 is a detector, 4 is an anode, 5 and 13 are openings, 6 is a cathode,
7 is a high speed valve, 8 is a vacuum vessel, 9 is a nozzle, 10 is a discharge switch, 11 is a discharge capacitor, 12 is plasma, 14 is an annular support, and 15 is a movable shutter. Figure 1 Figure 2 (A) (β) Akira 3 Figure 4

Claims (3)

[Claims] (1) An X-ray exposure apparatus using a gas injection plasma X-ray source, characterized by comprising means for measuring an X-ray intensity distribution on an exposure surface and means for moving an object to be exposed based on the X-ray intensity distribution. Exposure equipment. (2) The X-ray exposure apparatus according to claim 1, characterized in that a plurality of X-ray detectors are arranged on the exposure surface as means for measuring X-ray intensity. (3) The X-ray exposure apparatus according to claim 1, wherein a plurality of X-ray detectors are arranged between the X-ray source and the exposure surface as means for measuring X-ray intensity.