JPH04113299A - X-ray irradiation device and x-ray intensity distribution correcting filter - Google Patents

Abstract

PURPOSE:To improve pattern width accuracy within an exposure zone by inserting, between an X-ray generating part and a part to be irradiated, an X-ray intensity distribution correcting filter, constituted of membranes of which thickness or X-ray permeability is different from each other so as to make the distribution of X-ray strength at the part to be irradiated be uniform. CONSTITUTION:An X-ray intensity distribution adjustment filter 3 constituted of membranes of which X-ray permeability or thickness is different from each other so as to make the distribution of X-ray strength be uniform, is arranged between an X-ray generating part and a part to be irradiated. The distribution adjustment filter 3 of X-ray strength is constituted of an inorganic membrane (SiN, SiC, BN and so on), an organic membrane (a polyimide, a polypropyrene, a polyester, etc.) and a metallic membrane (Be, Ti, Al, etc.), all of which have different thickness distribution, or otherwise is constituted of inorganic, organic, metallic metallic membranes, etc., having different thickness distribution on a thin membrane base plate 13 which consists of the inorganic, the organic, the metallic membranes, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an X-ray irradiation device and an X-ray intensity distribution correction filter used for manufacturing high-density integrated circuits and analyzing materials.

[Prior Art] X-ray irradiation equipment includes SOR exposure beam lines used when synchrotron radiation is used, analysis beam lines, etc., and among these X-ray irradiation equipment, typical Here, we will describe an SOR exposure beamline that has a storage ring in the X-ray generating section and an exposure aligner in the irradiated device.

Recently, attempts have been made to use X-rays for fine batten transfer, and it has been reported that xig light is effective for fine batten transfer. In addition, synchrotron radiation has attracted attention as a high-power X-ray generator, and is being widely used in the manufacture of integrated circuits and the analysis of materials.

FIG. 8 is a schematic perspective view illustrating an example of a conventionally used X-ray exposure device, in which 1 is a storage ring, 2 is a condensing mirror, 4 is synchrotron radiation, 6 is a mask/wafer, and 7 is an X-ray extraction It's a window. In FIG. 8, the storage ring 1 and the beam line that transports the synchrotron radiation 4 are in an ultra-high vacuum on the order of 10-''' Torr. The synchrotron radiation 4 is extracted into the atmosphere through the X-ray extraction window 7.

In order to transfer the pattern onto the wafer, exposure is performed by moving the mask and the wafer at the same time.

The synchrotron radiation 4 is emitted at a wide angle in the horizontal direction, and in order to use the synchrotron radiation efficiently, it is condensed by a condenser mirror 2 for use. To collect the synchrotron radiation 4, a toroidal mirror in which a quartz substrate or a SiC substrate is coated with Au or Pt is currently used.

When a large convergence angle is used, the X-ray intensity of the synchrotron radiation collected by a toroidal mirror tends to become non-uniform, and as shown in FIG. 6(a), intensity non-uniformity of several tens of percent often occurs.

[Problems to be Solved by the Invention] On the other hand, in an exposure device used in LSI manufacturing, in order to accurately control the pattern width of a transferred pattern, exposure unevenness is reduced to 1.
It is kept at 2%. Since X-ray exposure is less affected by diffraction and interference, it may be less affected by exposure unevenness than photoexposure, but it is necessary to keep exposure unevenness to 5 to 10% or less.

Currently, there is no effective method. Either sacrifice exposure time and expose without condensing the light with a plane mirror, or improve the mask contrast and expose to match the intensity of the weakest part of the X-ray. is the current situation.

An object of the present invention is to make the xmn light intensity distribution uniform and to improve the accuracy of the batten width within the exposure area.

[Means to solve the problem]

In order to achieve the above object, the X-ray irradiation device of the present invention has an X-ray generation section and an irradiated section, in which the xIIA generation section and the irradiated section are provided with a The present invention is characterized in that an X-ray intensity distribution correction filter made of films having different distributions of X-ray transmittance or film thickness is arranged so that the X-ray intensity distribution of the irradiation part is uniform.

Further, the X-ray intensity distribution correction filter of the present invention is a filter for X-ray intensity distribution correction that is disposed between an X-ray generating section and an irradiated section of an X-ray irradiation device. It is characterized by being composed of films having different distributions of X-ray transmittance or film thickness so that the X-ray intensity distribution is uniform.

Furthermore, in the X-ray intensity distribution correction filter of the present invention, the film may include at least one inorganic film (for example, SiN, SiC, BN, etc.) or an organic film (for example, , polyimide, polypropylene, polyester, etc.), a metal film (e.g., Be, Ti%A1, etc.), or a thin film substrate consisting of an inorganic film, an organic film, or a metal film, with at least one film having a different thickness distribution. It is characterized by being composed of a single layer of inorganic film, organic film, and metal film.

[Effect]

In the present invention, between the X-ray generating part and the irradiated part, films having different distributions of X-ray transmittance or film thickness are formed so that the X-ray intensity distribution of the irradiated part is uniform. By arranging the X-ray intensity distribution correction filter, it is possible to make the xsaa light intensity distribution on the wafer, which is the irradiated part, uniform, and it is possible to improve the accuracy of the batten width in the exposure area.

Embodiment] FIG. 1 is a diagram showing an example of a beam line configuration in which an X-ray intensity distribution correction filter is inserted, showing a first embodiment of the present invention, where 1 is a storage ring and 2 is a condensing mirror. 3 is an X-ray intensity distribution correction filter, 4 is synchrotron radiation, 6 is a mask/wafer, 7 is an X-ray extraction window, and 8 is a positioning lever. The intensity distribution of the XIJA emitted from the condenser mirror 2 has a lot of intensity unevenness, as shown in FIG. 1(a). In particular, this tendency increases as the condensing angle φ increases. By passing it through the X-ray intensity distribution correction filter 3, the intensity distribution is made uniform as shown in (b).

Figure 2 is a diagram showing the details of the main parts of Figure 1, where 3 is the X-ray intensity distribution correction filter, 4 is the synchrotron radiation, and (A) is the synchrotron radiation when looking from downstream to upstream of the synchrotron radiation. 4 shows the intensity distribution, and (b) shows the intensity distribution after passing through the X-ray intensity distribution correction filter 3. The X-ray intensity distribution correction filter 3 has a thickness distribution in the width direction of the synchrotron radiation (direction of arrow d), and is configured to have the same thickness in the width direction of the synchrotron radiation and the direction perpendicular to the direction of the radiation (arrow e). It becomes. Therefore, the positioning of the filter for X-ray intensity distribution correction is done using the positioning lever 8 (Note:
The position of the positioning lever 8 in this figure and in FIG. 2 are reversed. ), it can be easily moved in the horizontal direction (direction of arrow d).

The X-ray intensity distribution before passing through the X-ray intensity distribution correction filter 3 has different X-ray intensities at the synchrotron radiation positions a, b, and c, as shown in (a). X with different film thickness depending on the X-ray intensity
By inserting the line intensity distribution correction filter 3, the X-ray intensity becomes uniform as shown in FIG. 2 (b) (the intensity at positions a'b'C' is uniform). The insertion position of the X-ray intensity distribution correction filter is basically to be inserted in a part where the intensity distribution is poor, and it may be placed at any position on the beam line. It is also possible to provide a film thickness distribution directly to the X-ray extraction window.

The X-ray intensity distribution correction filter 3 needs to have a film thickness that corresponds to the X-ray intensity distribution, that is, it is necessary to make the film thicker in areas where the X-ray intensity is strong and thinner in areas where it is weaker. Therefore, it is necessary to measure the intensity distribution of X-rays by some method and manufacture a filter having an X-ray transmittance distribution corresponding to the intensity distribution.

FIG. 3 is a diagram showing the manufacturing flow of the X-ray intensity distribution correction filter, in which the intensity distribution is measured at the position where the X-ray intensity distribution correction filter 3 of FIG. 1 is to be inserted. In method (2), a wafer coated with resist is placed at the filter insertion position and exposed. After development, the remaining film thickness of the resist is measured and the γ of the resist is determined.
Determine the X-ray intensity distribution from the characteristics. Next, an organic film, an inorganic film, or a metal film is selected for the filter, and the intensity distribution is converted into a film thickness distribution of the material from the X-ray wavelength distribution and the material's X-ray transmittance.

FIG. 4 is a diagram showing a method of manufacturing a correction filter by a vapor deposition method, in which 10 is a vapor deposition source, 11 is a slit, and 12 is a drive unit that moves the slit in the direction of arrow f. The slit driving unit 12 moves the slit 11 to deposit the filter material onto the filter 3 so as to obtain a prescribed film thickness distribution. Of course, it can be manufactured in the same manner by sputtering instead of vapor deposition. Further, in method (2) of FIG. 3, a negative type resist is used, and the base material is directly etched by exposure and development in the same manner as in (2), thereby making it possible to manufacture an X-ray intensity distribution correction filter in a self-aligning manner. Furthermore, method ■
In this case, it is also possible to measure the X-ray intensity distribution with a semiconductor X-ray detector and use the method (2) as a filter for correcting the X-ray intensity distribution.

X-ray intensity distribution correction filter 3 manufactured using these methods
are shown in FIGS. 5(a) and (b). In Figure 5, 13
9 is a filter substrate made of 5iN1SiC, Be, etc., and 9 is a filter material having a different film thickness.

In addition, (a) is an X-ray intensity distribution correction filter in which the film thickness of a material with relatively high X-ray transmittance, such as polyimide or A1, is used to correct the X-ray intensity distribution, and (b) is an X-ray intensity distribution correction filter using This is an X-ray intensity distribution correction filter that uses a thin film such as sjN, SiC, Be, etc. having a high ratio as a substrate, and has a film thickness configured to match the X-ray intensity distribution and correct X-ray intensity unevenness thereon. So far, we have talked about X-ray intensity distribution correction filters made of the same material but with different film thicknesses, but of course, Au,
Similar results can be obtained with an X-ray intensity distribution correction filter that combines a plurality of heavy metals such as Ta and light metals such as A1%Be.

Figure 6 shows the X-ray intensity distribution obtained by measuring the X-ray intensity distribution and correcting the intensity unevenness. Ta film thickness distribution (formed on a SiN substrate) tailored to (c) is (b)
) shows an X-ray intensity distribution corrected by inserting an X-ray intensity distribution correction filter having a film thickness distribution.

So far, we have described a beamline that uses a method of swinging the mask/wafer 6, but we have also described a method of swinging a mirror in the direction of arrow g to expand the exposure area as shown in Figure 7. By inserting the intensity distribution correction filter 3, the X-ray intensity can be corrected. At this time, since the X-ray intensity unevenness spreads in two dimensions, the positioning of the filter is
It is necessary to position both.

Although the present invention has been specifically described above based on the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various changes can be made without departing from the gist thereof. For example, in the above embodiment, the X-ray intensity distribution of the irradiated area was made uniform by adjusting the film thickness distribution, but by adjusting the material or both the material and the film thickness, the X-ray transmittance could be The distribution may be controlled to make the X-ray intensity distribution of the irradiated area uniform.

〔Effect of the invention〕

As explained above, in the present invention, films having different X-ray transmittances or film thicknesses are formed between the X-ray generating part and the irradiated part so that the X-ray intensity distribution of the irradiated part is uniform. By inserting an X-ray intensity distribution correction filter, exposure unevenness can be reduced, and pattern width control of a transferred pattern during X-ray exposure becomes easier.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing an embodiment of the present invention.
An enlarged view of the line intensity distribution correction filter section, FIG. 3 is a diagram showing the manufacturing flow of the X-ray intensity distribution correction filter of the present invention, and FIG. 4 is a diagram showing the manufacturing method of the X-ray intensity distribution correction filter of the present invention. , FIGS. 5(a) and 5(b) are diagrams showing the configuration of the X-ray intensity distribution correction filter of the present invention, FIGS. 6(a) and (b),
(c) is a diagram showing the X-ray intensity unevenness before and after inserting the filter of the present invention, FIG. 7 is a diagram showing a beam line configuration using a mirror rocking method, and FIG. 8 is a diagram showing a conventional technique. 1... Storage ring 2... Focusing mirror 3... Filter for X-ray intensity distribution correction 4... Synchrotron radiation 6... Mask/wafer 7... X-ray extraction window 8... Positioning Lever 9...Filter material 0...Vapor deposition source L...Slit 2...Slit drive unit 3...Filter board Patent applicant Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. In an X-ray irradiation device having an X-ray generating section and an irradiated section, an X-ray intensity distribution of the irradiated section is uniform between the X-ray generating section and the irradiated section. An X-ray irradiation device characterized in that an X-ray intensity distribution correction filter is arranged which is composed of films having different distributions of X-ray transmittance or film thickness. 2. In the X-ray intensity distribution correction filter used by being placed between the X-ray generating part and the irradiated part of the X-ray irradiation device, so that the X-ray intensity distribution of the irradiated part becomes uniform, X
An X-ray intensity distribution correction filter comprising films having different distributions of radiation transmittance or film thickness. 3. The above film is composed of at least one inorganic film, organic film, or metal film with a different distribution of film thickness, or is formed on a thin film substrate consisting of an inorganic film, an organic film, or a metal film with different film thicknesses. An X-ray intensity distribution correction filter comprising at least one layer of an inorganic film, an organic film, and a metal film having a distribution.