JP3068913B2 - X-ray exposure apparatus and its installation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for performing exposure using X-rays, and more particularly, to an X-ray capable of precisely adjusting an optical axis of an X-ray radiation beam and an optical axis of an alignment optical system. An exposure apparatus and a method for installing the same are provided.

[0002]

2. Description of the Related Art Conventionally, an optical exposure apparatus has been generally used to form an LSI pattern. However, with the miniaturization of an LSI pattern, forming a miniaturized pattern with an optical exposure apparatus requires a resolution. It is approaching its limit in terms of aspects. Therefore, recently, an X-ray exposure apparatus capable of forming a finer pattern than a light exposure apparatus has been developed. This X-ray exposure apparatus requires an X-ray source of high volatility, and as such an X-ray source, a synchrotron or less (hereinafter referred to as SOR) has been attracting attention. FIG. 4 is a schematic configuration diagram showing a conventional general X-ray exposure apparatus using SOR as an X-ray source.

That is, X radiated from an SOR (not shown)
The X-ray irradiation beam 1 is reflected by an X-ray reflection mirror, passes through an ultra-high vacuum port 2, and enters a chamber 5 of an exposure apparatus main body 4 from an X-ray extraction window 3 mounted on the front end surface.

The chamber 5 is provided with a helium atmosphere in order to prevent the attenuation of the X-ray irradiation beam 1, and a mask stage 7 for movably holding an X-ray mask 6 and a semiconductor wafer 8 therein. A wafer stage 9 movably held and an alignment optical system 10 for detecting a positional shift between the X-ray mask 6 and a pattern drawn on the semiconductor wafer 8 are housed therein.

[0005] As a result, the X-ray irradiation beam 1 taken into the chamber 5 from the X-ray extraction window 3 is irradiated on an X-ray mask 6, and X-rays are applied to the surface of the semiconductor wafer 8 through the X-ray mask 6. Irradiation exposes the wiring pattern of the X-ray mask 6 on the semiconductor wafer 8.

Further, the exposure apparatus main body 4 is installed on an anti-vibration table 12 provided with an air spring 11 as an elastic body at a lower portion, so that anti-vibration measures against dark vibration and shock disturbance from the floor 13 can be taken. It has been subjected.

Since the X-ray irradiation beam 1 obtained by SOR is a horizontally radiated and horizontally radiated beam, the irradiation area where the wiring pattern of the X-ray mask 6 is exposed and transferred onto the semiconductor wafer 8 is defined. SO to expand
An X-ray reflection mirror is provided between R and the exposure apparatus main body 4, and the X-ray irradiation beam 1 is oscillated by swinging this mirror up and down. For this reason, the X-ray irradiation beam 1 incident on the exposure apparatus main body 4 has an incident angle of 2
The beam has a double angle.

In addition, since the wiring pattern on the X-ray mask 6 and the wiring pattern on the semiconductor wafer 8 are transferred while being accurately overlapped with each other, the alignment optical system 10 and the exposure optical system used for the transfer are required to have a predetermined size. It must be stable and accurate. For example, the mask stage 7, the wafer stage 9, and the alignment optical system 10
As a result, mechanically assembled and adjusted with high accuracy.

For this reason, in an X-ray exposure apparatus utilizing SOR, it is required to precisely adjust the optical axis of the X-ray irradiation beam 1 as the exposure light and the alignment optical system 10 of the exposure apparatus. .

In other words, as shown in FIG. 5, the wiring pattern 6a on the X-ray mask 6 and the wiring pattern 8a formed on the semiconductor wafer 8 coated with the resist 14 are transferred in a precisely overlapping manner. The position of the X-ray mask 6 and the position of the semiconductor wafer 8 are adjusted so that the displacement between the transfer position of the mask pattern determined by the direction of the X-ray irradiation beam 1 and the pattern formed on the semiconductor wafer 8 becomes zero. Need to be done. That is, the optical axis 1a of the X-ray irradiation beam 1
Needs to coincide with the optical axis 10a of the measurement standard of the alignment optical system 10. If they do not match, the gap between the X-ray mask 6 and the semiconductor wafer 8 is G,
Optical axis 1a of X-ray irradiation beam 1 and alignment optical system 10
Assuming that the angle difference from the optical axis 10a of the measurement reference is Δθ, δ
= G × Δθ.

Since the X-ray irradiation beam 1 is reflected from the SOR by the X-ray reflecting mirror and enters the exposure apparatus main body 4 as described above, the floor on which the exposure apparatus main body 4 is installed is usually used. 13 (usually a horizontal plane) is not parallel, and has an inclination of several degrees with respect to the horizontal plane. On the other hand, since the exposure apparatus main body 6 is normally assembled and adjusted with reference to a horizontal plane, the optical axis 10a of the alignment optical system 10 as a measurement reference is substantially horizontal.

Therefore, as means for making the optical axis 1a of the X-ray irradiation beam 1 coincide with the optical axis 10a of the measurement reference of the alignment optical system 10, two parallel images are provided between the SOR and the exposure apparatus main body 4. X-ray reflecting mirrors are arranged at predetermined intervals, and the X-ray irradiation beam 1 is reflected twice by the two X-ray reflecting mirrors to make horizontal light, or the exposure apparatus body 4 is installed. Generally, the angle of the X-ray reflection mirror is adjusted according to the position and the inclination.

However, in the former of the above-mentioned conventional example, since two X-ray reflecting mirrors are used to reflect the light twice, the attenuation of the X-ray irradiation beam becomes large,
Further, in the latter case, the tilt angle of the X-ray reflection mirror is deviated from the optimum reflection angle depending on the installation position and the tilt of the exposure apparatus main body, so that the X-ray irradiation beam cannot be sufficiently used together,
There has been a problem that the function as an X-ray exposure apparatus using SOR cannot be sufficiently exhibited.

[0014]

As described above, the conventional X
The X-ray exposure apparatus has a problem that the X-ray irradiation beam cannot be sufficiently used, and the function as the X-ray exposure apparatus using SOR cannot be sufficiently exhibited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an exposure apparatus main body is fixed by easily aligning an optical axis of an X-ray irradiation beam with a measurement reference optical axis of an alignment optical system. Accordingly, an object of the present invention is to provide an X-ray exposure apparatus capable of sufficiently exhibiting the function as an X-ray exposure apparatus and a method of installing the same.

[0016]

In order to achieve the above object, an X-ray exposure apparatus according to the present invention comprises an X-ray source for generating X-rays, and an X-ray source provided separately from the X-ray source to form an exposure space. An apparatus main body having a casing, an alignment optical system housed in an exposure space, support means provided on a base for swingably supporting the apparatus main body, and the alignment means provided on the support means. Floating means for adjusting the height and tilt of the device body so that the optical axis of the optical system coincides with the axis of the X-ray; and fixing the device body after adjusting the height and tilt. And fixing means for performing the operation.

Further, according to the installation method of the present invention, an X-ray source which is separated from an X-ray source for generating X-rays, is supported on a base by a support means, and has an apparatus main body containing an alignment optical system.
In the installation method of the line exposure apparatus, a lifting step of the apparatus body with respect to the supporting means by a floating means on a supporting means, and adjusting the height and inclination of the apparatus body by controlling the floating means, An adjusting step of aligning an X-ray axis with an optical axis of the alignment optical system; and a fixing step of fixing the apparatus main body on the support means after adjusting the height and the inclination in this manner. And

[0018]

According to the X-ray exposure apparatus and the installation method thereof, when the exposure apparatus main body is installed, after the apparatus main body is stably swingably mounted on the base via the elastic body, The apparatus main body is levitated by levitation means, and its height and inclination are adjusted so that the optical axis of the X-ray irradiation beam and the optical axis of the measurement standard of the alignment optical system of the apparatus main body coincide with high accuracy. In this state, it can be fixed on the support means by the fixing means. Therefore, since the optical axis of the X-ray irradiation beam and the optical axis of the alignment optical system can be easily and accurately aligned and installed, the function as an X-ray exposure apparatus can be sufficiently exhibited.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 or FIG. 2 schematically shows an actual system, and its positional relationship, dimensions, and the like are expressed so that the actual system can be easily described.

FIG. 1 shows the overall configuration of the present invention. The SOR 30, the X-ray reflection mirror 31, the air supply device 24 to the air cushion 15, the regulating valve 23, the air pipe 22, the control device 21, and the like. Although the example of the dimensions of the main part is entered, in FIG. 2 the illustration of the above-described components and dimensions is omitted because of the explanatory view of the fixed apparatus main body after the adjustment. The conventional X shown in FIG. 4 or FIG.
The same parts as those of the line exposure apparatus are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, X radiated from SOR 30
The X-ray irradiation beam 1 is reflected by the X-ray reflection mirror 31, passes through the ultra-high vacuum port 2, and enters the chamber 5 of the exposure apparatus main body 4 from the X-ray extraction window 3 mounted on the front end face. However, the X-ray irradiation beam 1 is emitted horizontally from the SOR 30 and is reflected by the X-ray reflection mirror 31 at an optimum reflection angle. That is, the light is incident on the exposure apparatus main body 4 with an inclination of several degrees with respect to the horizontal plane.

Therefore, as shown in FIG. 5, the exposure apparatus main body 4 must also be tilted so that the optical axis 1a of the X-ray irradiation beam 1 and the optical axis 10a of the measurement standard of the alignment optical system 10 coincide with each other. There is.

As shown in FIG. 1, the distance from the SOR 30 to the X-ray reflecting mirror 31 is L ₁ , the distance from the X-ray reflecting mirror 13 to the semiconductor wafer 8 is L ₂ , and the SOR 30
Let D be the major axis of an actual X-ray exposure apparatus, for example, L
₁ = 2 to 10 m, L ₂ = 5 to 15 m, and the incident angle α of the beam 1 to the exposure apparatus main body 4 is 40 to 50 mrad. In FIG. 1, for example, L ₂ = 10 m, α50 mra
When d and D = 20 m, the height difference ΔH between the X-ray reflection mirror 31 and the semiconductor wafer 8 is 500 mm, and the inclination of the exposure apparatus body 4 (the difference between the front and rear heights) is Δh = h ₁ -h _Two
= 50 mm.

On the other hand, the irradiation area of the semiconductor wafer 8 has a side of about 20 to 30 mm, and the adjustment amount of the beam 1 is usually 1 mm or less. As described above, since the adjustment of the beam 1 is extremely small compared to the length from the SOR 30 to the exposure apparatus main body 4, the operation of adjusting the beam 1 is extremely difficult.

For this reason, in the X-ray exposure apparatus of the present invention, the upper surface of the vibration isolation table 12 held horizontally via the air spring 11 as an elastic body and the lower surface of the exposure apparatus main body 4 installed here. An air cushion 1 serving as a floating means for adjusting the position and angle of the exposure apparatus main body 4 by lifting and supporting the lower peripheral edge of the exposure apparatus main body 4 so as to be adjustable in height.
5 and the exposure apparatus main body 4 whose position and angle have been adjusted by the floating means
There is provided a fixing means including an adjuster bolt 16 and a tightening bolt 17 for fixing the fixing bolt 17 on the upper surface of the fixing device.

That is, the air cushion 15 as the levitation means expands in the vertical direction in the figure when air is introduced into the interior thereof and extends its length. The four air cushions 15 are arranged at four corners on the lower surface, and the position and angle of the exposure apparatus main body 4 can be adjusted by individually adjusting the heights of these four air cushions 15. The air cushion 15 is shown in FIG.
As shown in FIG. 3, the upper plate 25 and the lower plate 26 have a rubber side portion 27 connecting the upper plate 25 and the lower plate 26. The lower plate 26 is connected to the air pipe 22.

As shown in FIG. 1, each air pipe 22 connected to the air cushion 15 is provided with an adjusting valve 23 so that the amount of air from the air supply device 24 is adjusted. On the other hand, on the vibration isolation table 12, a front height meter 20a and a rear height meter 20b for measuring front and rear heights of the exposure apparatus main body 4 are provided. These front height meters 20
a and the rear height meter 20b are connected to a control device 21 that independently controls the regulating valve 23.

On the other hand, the adjust bolt 16 is
The head can be moved spherically, and for example, one at each of the vertices of an equilateral triangle, two at each of the four points, for a total of four Are located. In short, three or more points on the lower surface of the exposure apparatus main body 4 are supported, and this vertical movement is regulated. The tightening bolt 17 is screwed to a bracket 18 erected on the periphery of the exposure apparatus main body 4 so as to freely project in the lateral direction. Is restricted in the lateral direction.

Next, a method of positioning the exposure apparatus main body 4 will be described. First, the X-ray irradiation beam 1 is actually irradiated from the SOR 30. Next, from the X-ray reflection mirror 31 to the semiconductor wafer 8
At any two points, the heights H ₁ and H ₂ from the vibration isolation table 12 to the beam 1 are adjusted to a known value such as a fluorescent plate (a part of which emits light when irradiated with X-rays) or an X-ray monitor. Measure using the method. Next, the values of the heights H ₁ and H ₂ are input to the controller 21, and the controller 21
From 2 to exposure point of the semiconductor wafer 8 the height H _3, determined based on the value of the height H ₁ and H _2, at the same time alignment optical front height h ₁ and rear height h ₂ of the exposure apparatus main body 4 The axis of the system 10 and the axis of the X-ray irradiation beam are set to coincide.

During this time, the actual values of the front height h ₁ and the rear height h ₂ are input to the control device 21 from the front height meter 20a and the rear height meter 20b, and the front height h ₁ and the rear height based on the set value of h ₂ and the measured value, and controls the respective adjusting valve 23 by the controller 21. Next, as shown in FIG.
Then, the floating mechanism is released, that is, the air in the air cushion 15 is released.

In this state, the function of the X-ray exposure apparatus is operated, and as shown in FIG.
It is possible to check whether a and the optical axis 10a of the measurement standard of the alignment optical system 10 are adjusted to the required range. Therefore, if it is determined by this check that the adjustment is not within the required range, the levitation means, that is, the air cushion 15 is operated again to perform the adjustment again. Can be done.

Thus, the exposure apparatus main body 4 which is installed separately from the SOR 30 and whose horizontal plane and vertical plane with respect to the X-ray irradiation beam 1 need to be adjusted to required accuracy is used as an X-ray exposure apparatus. X-ray irradiation beam 1 from SOR 30 at the installation location without impairing the function of
And the optical axis of the exposure apparatus main body 4 can be adjusted so as to coincide with the optical axis of the alignment optical system.

In the above embodiment, the air cushion is described as an example of the floating means. However, the present invention is not limited to this, and a known floating means such as a hydraulic jack can be applied.

Further, instead of an adjuster bolt having a spherical seat, a tapered fixing metal can be used as a fixing means, and an adjuster bolt can be used instead of the tightening bolt. In addition, although the embodiment has been described in which the height and inclination of the apparatus main body are automatically adjusted and controlled by the control device 21, such adjustment may be performed manually.

While one embodiment of the present invention has been described above, the present invention can be variously modified and implemented in addition to the above-described embodiment without departing from the scope of the invention.

[0036]

As described above in detail, according to the present invention, X
X-ray exposure that can fully demonstrate the function of an X-ray exposure device by fixing the exposure device body by easily aligning the optical axis of the X-ray irradiation beam with the measurement reference optical axis of the alignment optical system. An apparatus and an installation method thereof can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of an X-ray exposure apparatus according to the present invention, showing a state in which the apparatus main body is floated by a levitation means to perform positioning.

FIG. 2 is a schematic view showing an embodiment of the X-ray exposure apparatus according to the present invention, showing a state in which the apparatus main body is fixed.

FIG. 3 is a schematic diagram showing an example of a levitation means applicable to the X-ray exposure apparatus of the present invention.

FIG. 4 is a schematic view showing a conventional X-ray exposure apparatus.

FIG. 5 is an enlarged view of an exposure unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray irradiation beam 1a X-ray irradiation beam optical axis 2 port 4 exposure apparatus main body 5 chamber 6 X-ray mask 8 semiconductor wafer 10 alignment optical system 10a alignment optical system optical axis 11 air spring (elastic body) 12 anti-vibration table (Supporting means) 13 Floor (fixed part) 15 Air cushion (floating means) 16 Adjuster bolt (fixing means) 17 Tightening bolt (fixing means) 20a, 20b Height gauge 21 Controller 23 Adjustment valve 30 SOR (X-ray source) 31 X-ray reflection mirror

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 7/20

Claims (4)

(57) [Claims] 1. An X-ray source for generating X-rays, an apparatus main body having a casing separately provided from the X-ray source and forming an exposure space, an alignment optical system housed in the exposure space, and a fixed body. support means disposed on parts supporting swingably said apparatus main body, is disposed on the support means, such that the axis of the alignment optical system of the optical axis and the X-ray is coincident, the device An X-ray exposure apparatus comprising: a levitation means for adjusting a height and a tilt by floating a main body; and a fixing means for fixing the apparatus main body after the height and the tilt are adjusted. Wherein said supporting means comprises a anti-vibration table, and disposed an elastic member between the fixing portion and the anti-vibration table,
2. The X-ray exposure apparatus according to claim 1, wherein the levitation means includes an expansion / contraction means fixed to the vibration isolation table and capable of expanding and contracting in the direction of gravity to lift the apparatus main body. 3. A method of installing an X-ray exposure apparatus having an apparatus main body which houses an alignment optical system and is supported on a base by being separated from an X-ray source for generating X-rays, wherein a step of causing floating the apparatus body relative to the support means by means the optical axis of this by controlling the flying means to adjust the height and tilt of the apparatus main body, said alignment optical system and the axis of the X-ray And a fixing step of fixing the apparatus main body on the support means after adjusting the height and the inclination in this manner. Wherein said adjusting step, the front height of the apparatus main body as on the basis of the height of at least two points of the X-ray, and the axis of the alignment optical system of the optical axis and the X-ray coincides and a calculation step of calculating a posterior height, and a measurement step of measuring the actual forward height and posterior height of the device body, on the basis of the respective calculated values and measured values of the calculating step and the measuring step 4. The method according to claim 3, wherein the levitation means is controlled.