JPH0795511B2 - X-ray exposure mask and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to X-ray lithography used in X-ray lithography and the like.
The present invention relates to a line exposure mask and a method for manufacturing the same.

[Conventional technology]

FIG. 5 is a diagram showing an example of a manufacturing process of an X-ray exposure mask.

First, a mask support 2 made of, for example, a silicon single crystal substrate is prepared ((A) in the figure), and an X-ray transparent support 4 made of, for example, boron nitride (BN) or silicon nitride (SiNx) is provided thereon. , CVD method, ion plating method, combined use of vacuum vapor deposition and ion irradiation, etc. (FIG. 2B). Then, an X-ray absorber 6 made of, for example, Au, Ta, W or the like is formed thereon by a vapor deposition method, a plating method, or the like (FIG. 7C). As a result, a mask (mask blanks) 7 before being subjected to processing such as patterning is obtained.

After that, for example, a resist 8 is applied on the X-ray absorber 6 (FIG. 7D), and after the resist 8 is patterned (FIG. 8E), the X-ray absorber 6 is ion-etched or the like. The resist 8 is removed by patterning (FIG. 6 (F)), and finally, the mask support 2 is windowed by using the X-ray transparent support 4 as an etching stop layer by wet etching or the like. The mask 10 for X-ray exposure thus obtained is obtained ((G) in the same figure).

[Problems to be solved by the invention]

The X-ray absorber 6 is generally formed by the vapor deposition method described above,
Since it is formed on the X-ray permeable support 4 by a plating method or the like, the adhesion between the two is poor, and therefore the X-ray absorber 6 may peel off as the temperature rises during X-ray irradiation. It was

That is, at the time of X-ray irradiation, the X-ray absorber 6 and the like generate heat by absorbing X-rays, which raises the temperatures of the X-ray absorber 6 and the X-ray transparent support 4 and the like. The X-ray absorber 6 is made of a metal such as Au, Ta or W, and the X-ray transparent support 4 is made of a ceramic such as boron nitride or silicon nitride. Heat stress occurs. Therefore, if the adhesion between the two is poor, the X-ray absorber 6 may peel off and fall off, causing problems such as the occurrence of patterning defects and the deterioration of pattern accuracy, making it impossible to perform accurate pattern transfer.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an X-ray exposure mask and a method for manufacturing the same, which solves such problems.

[Means for solving problems]

The mask for X-ray exposure of the present invention comprises a substance forming the X-ray absorber and a substance forming the X-ray transmissive support near the interface between the X-ray absorber and the X-ray transmissive support as described above. And the proportion of the substance constituting the X-ray transparent support is continuously reduced as the X-ray transparent support is approached, and the proportion of the substance constituting the X-ray transparent support is continuously reduced. It is characterized in that an increasing number of mixed layers are formed.

A first manufacturing method of the present invention provides a mask support having an X-ray transmissive support formed thereon and an X-ray absorber formed thereon, respectively. By injecting accelerated inert gas ions, a substance forming the X-ray absorber and a substance forming the X-ray transparent support are formed in the vicinity of the interface between the X-ray absorber and the X-ray transparent support. , And the proportion of the substance constituting the X-ray transparent support continuously decreases and the proportion of the substance constituting the X-ray transparent support continuously increases as the X-ray transparent support is approached. A mixed layer is formed.

A second manufacturing method of the present invention provides a mask support on which an X-ray transmissive support is formed, and prepares a metal for constructing an X-ray absorber with respect to the X-ray transmissive support in vacuum. Vapor deposition of
By irradiating accelerated metal ions of the same kind as the metal or an inert gas ion, an X-ray absorber is provided on the X-ray transparent support, and an X-ray absorber near the interface between the two. And a substance forming the X-ray transparent support are mixed with each other, and the proportion of the substance forming the X-ray absorber continuously decreases as the X-ray transparent support approaches, and X It is characterized by forming a mixed layer in which the ratio of substances constituting the linearly transparent support is continuously increased.

[Action]

In the X-ray exposure mask of the present invention, the mixed layer acts like a wedge, so that the adhesion of the X-ray absorber to the X-ray transparent support is improved.

According to the first manufacturing method of the present invention, the substance constituting the X-ray absorber is struck into the X-ray permeable support body by the inert gas ions, or the substance constituting the X-ray permeable support body together therewith. Is struck out into the X-ray absorber, and a mixed layer as described above is formed in the vicinity of the interface between the X-ray absorber and the X-ray transmissive support.

According to the second manufacturing method of the present invention, the X-ray absorber is formed on the X-ray transparent support by vapor deposition of the X-ray absorber constituent metal, and the X-ray absorber is formed by the irradiated ions. The constituent substance is hammered into the X-ray transparent support, or the substance constituting the X-ray transparent support is hammered out into the X-ray absorber together with the X-ray absorber and the X-ray transparent substance. In the vicinity of the interface with the support, the above-mentioned mixed layer formed by mixing both constituent materials is formed.

〔Example〕

FIG. 1 is a schematic sectional view partially showing an example of an X-ray exposure mask according to the present invention.

The X-ray exposure mask 12 of this embodiment has, for example, the X-ray absorber 6 as described above, the X-ray transmissive support 4 that supports it, and the mask support 2 that supports it. There is.
Moreover, in the vicinity of the interface between the X-ray absorber 6 and the X-ray transparent support 4, both structural materials (for example, when the X-ray absorber 6 is made of Au and the X-ray transparent support 4 is made of BN, And BN)
A mixed layer 14 is formed by being mixed with each other. Moreover, in this mixed layer 14, for example, as shown in FIG.
As the X-ray transparent support 4 is approached, the proportion of the substance forming the X-ray absorber 6 continuously decreases and the proportion of the substance forming the X-ray transparent support 4 continuously increases.
In addition, in the illustrated example, the X-ray absorber 6 or the mask support 2 is not subjected to processing such as patterning or windowing, but these are, for example, steps shown in FIGS. 5 (D) to (G). And processed appropriately.

In the X-ray exposure mask 12, the mixed layer 14 acts like a wedge, so that the adhesion of the X-ray absorber 6 to the X-ray transparent support 4 becomes very high. Moreover, X
The difference in the coefficient of thermal expansion between the X-ray absorber 6 and the X-ray transparent support 4 can be absorbed by the mixed layer 14 having a continuously changing composition, so that the X-ray absorber 6 and the X-ray transparent support 4 can be absorbed. The occurrence of heat stress during the period is also suppressed.

As a result, exfoliation of the X-ray absorber 6 due to the temperature rise during X-ray irradiation is eliminated, so that pattern defects due to the X-ray absorber falling off, which is a defect of the conventional mask, and deterioration of pattern accuracy are caused. There is no problem and accurate pattern transfer is possible.

Next, an example of a method of manufacturing the above X-ray exposure mask 12 will be described with reference to FIG. 2 or FIG.

FIG. 2 shows an example of an apparatus for carrying out the method by ion implantation. That is, as described above, the X-ray transparent support 4 is provided on the mask support 2, and the X-ray absorber 6 is further provided on the known CV.
Prepared by D method, PVD method, etc., attach them to the holder 16 and attach them to a vacuum container (not shown).
The ion source that is housed inside the X-ray absorber 6
18 are arranged.

In this example, the ion source 18 is a bucket type ion source that uses a multi-pole magnetic field for plasma confinement, and is capable of accelerating uniform and large-area ions (ion beam) 20 to irradiate / implant the X-ray absorber 6. it can. However, instead of such a bucket type ion source, another type of ion source can be used.

During processing, the vacuum vessel is evacuated to, for example, about 10 ^-5 to 10 ^-7 Torr, and then the ion source 18 is used to generate ions 20.
Extraction of inert gas ions such as Ne, Ar, Kr etc.
It is injected from the side of the line absorber 6. As a result, the substance forming the X-ray absorber 6 is struck into the inside of the X-ray permeable support 4 by the inert gas ions 20, or the substance forming the X-ray permeable support 4 together with the X-ray permeable support 4 is changed. Absorber 6
The mixed layer 14 is formed by mixing the constituent materials of the X-ray absorber 6 and the X-ray transparent support 4 near the interface between the X-ray absorber 6 and the X-ray transparent support 4 (see FIG. 1). ) Is formed. As a result, the X-ray exposure mask 12 as described above is used.
Is obtained.

In the above case, the thickness of the mixed layer 14 can be adjusted by the energy of the ions 20 and the like.

Further, regarding the relationship between the energy of the ions 20 and the film thickness of the X-ray absorber 6 which is formed in advance, the range of the ions 20 (average projected range) becomes approximately the same as the film thickness of the X-ray absorber 6. Preferably. This is because the mixed layer 14 can be effectively formed in the vicinity of the interface between the X-ray absorber 6 and the X-ray transparent support 4 by doing so.

However, if the energy of the ions 20 is too large, the sputtering action or the like on the X-ray absorber 6 cannot be neglected. Therefore, it is preferable to set the energy of the ions 20 to several KeV to several tens KeV. If the film thickness of the X-ray absorber 6 is not sufficient, first, the X-ray transparent support 4
After forming the mixed layer 14 by forming the X-ray absorber 6 to a thickness of about the range of the ions 20, the film thickness of the X-ray absorber 6 may be further increased to a desired film thickness. .

Further, the incident angle θ of the ions 20 with respect to the vertical line on the surface of the X-ray absorber 6 is preferably within the range of 0 ° to 60 ° from the viewpoint of preventing the sputtering of the X-ray absorber 6 and the like.

In addition, the amount of ions 20 injected is too small, it is difficult to form the mixed layer 14, and conversely, if the amount is too large, gas voids or the like are likely to be formed inside the mixed layer 14, etc., and therefore about 10 ¹⁵ to 10 ¹⁸ ions / cm ^2. Is preferred.

FIG. 3 shows an example of an apparatus for carrying out the method using both vacuum deposition and ion irradiation. That is, an X-ray transparent support 4 formed on the mask support 2 as described above by a known CVD method, PVD method or the like is prepared and attached to a holder 16 and a vacuum container (not shown) is provided. ), And the evaporation source 22 and the ion source 18 as described above are arranged toward the X-ray transparent support 4.

The evaporation source 22 is an electron beam evaporation source in this example, and by heating and evaporating the evaporation material 24 with an electron beam, the metal 26 for forming the X-ray absorber 6 as described above, for example, Au, Ta, W. Etc. can be deposited on the surface of the X-ray transparent support 4. However, other types of evaporation sources can be used instead of such electron beam evaporation sources.

The deposition rate of the metal 26 on the X-ray transparent support 4 or the film thickness of the film formed on the X-ray transparent support 4 can be measured by the film thickness monitor 28.

In this case, from the ion source 18, as the ions 20, the metal
Extract metal ions similar to 26 or inert gas ions as described above.

During processing, the inside of the vacuum vessel is evacuated to, for example, about 10 ⁻⁵ to 10 ⁻⁷ Torr, and then the above metal from the evaporation source 22 is discharged.
26 is deposited on the X-ray transparent support 4, and the ion source 18
The ions 20 as described above are irradiated toward the X-ray transparent support 4.

In that case, as a mode of vapor deposition of the metal 26 and irradiation of the ions 20 on the X-ray transparent support 4, a method of simultaneously performing both to obtain an X-ray absorber 6 having a desired film thickness, and after performing both simultaneously, If necessary, the metal 26 is vapor-deposited to obtain the X-ray absorber 6 having a desired film thickness, and the metal 26 is vapor-deposited in advance and the irradiation of the ions 20 is alternately performed a predetermined number of times to obtain the X-ray absorber having the desired film thickness. A method of obtaining the line absorber 6 or the like can be adopted.

By the above treatment, the mixed layer 14 (see FIG. 1) as described above is formed on the X-ray transparent support 4, and the X-ray absorber 6 as described above is formed thereon. The mixed layer 14 is formed because the metal 26 for forming the X-ray absorber 6 deposited on the X-ray transparent support 4 is applied to the inside of the X-ray transparent support 4 by the irradiated ions 20. This is due to the action of being knocked in or hammered out into the X-ray absorber 6 in which the substance forming the X-ray transparent support 4 is deposited.
As described above, the X-ray exposure mask 12 as described above is obtained.

Also in this case, when the vapor deposition of the metal 26 and the irradiation of the ions 20 are alternately performed, the X formed on the X-ray transparent support 4 first is formed.
It is preferable that the thickness of the line absorber 6 is set to a thickness of the range of the ions 20 to be irradiated / implanted later. Further, the preferable range of the energy of the ions 20, the incident angle θ, the implantation amount, etc. is the second
This is almost the same as the case of the method described in the figure. Both are due to the reasons described above.

Next, a specific experimental example by the method described in FIG. 3 will be shown.

Experimental Example 1 An X-ray transparent support 4 made of boron nitride (BN) was formed on the mask support 2 made of a silicon single crystal substrate to a thickness of 4 μm by a thermal CVD method. For the transparent support 4, Au is used as the metal 26 from the evaporation source 22.
Was evaporated and evaporated at a rate of about 10 Å / min, and Ar ions were irradiated as ions 20 from the ion source 18 at an energy of about 5 KeV to 20 KeV to form the mixed layer 14 with a thickness of about 10 Å to 1000 Å. Thereafter, the irradiation of the ions 20 was stopped, and only the vapor deposition was performed to form Au as the X-ray absorber 6 with a thickness of about 3000 Å on the mixed layer 14.

An example of the analysis data in the depth direction from the surface by Auger electron spectroscopy (AES) of the mask 12 for X-ray exposure thus obtained is shown in FIG. The absolute intensity on the vertical axis corresponds to the density of each element, and the etching time on the horizontal axis corresponds to the depth from the surface. A mixed layer 14 made of Au and BN and having a continuously changing composition is formed near the interface between Au which is the X-ray absorber 6 and BN which is the X-ray transparent support 4. I understand.

Experimental Example 2 An X-ray transparent support 4 formed on the mask support 2 and the same as in the case of the above-mentioned Example 1 was prepared.
Approximately 300 Å of Au is vapor-deposited on the linear permeable support 4, and then Ar
Ions were irradiated and implanted with 10 ¹⁶ to 10 ¹⁸ ions / cm ² at an energy of 30 KeV to form a mixed layer 14. And after that, Au
Was evaporated to form an X-ray absorber 6.

In each of the experimental examples described above, the X-ray exposure mask 12 having good adhesion to the X-ray absorber 6 was obtained due to the presence of the mixed layer 14.

〔The invention's effect〕

As described above, according to the X-ray exposure mask of the present invention, since the mixed layer acts like a wedge, the adhesion of the X-ray absorber to the X-ray transparent support is very high, and The difference in the coefficient of thermal expansion between the X-ray absorber and the X-ray transparent support can be absorbed by the mixed layer whose composition changes continuously, so that the thermal stress between the X-ray absorber and the X-ray transparent support occurs. Since the peeling of the X-ray absorber due to the temperature rise during X-ray irradiation can be suppressed as a result, the occurrence of pattern defects due to peeling-off of the X-ray absorber, which was a defect of the conventional mask, A problem such as deterioration of pattern accuracy is eliminated, and accurate pattern transfer becomes possible.

Further, according to the manufacturing method of the present invention, the mixed layer as described above can be formed without the need for heating the base material at a high temperature by the impacting and ejecting action of the X-ray absorber constituent substances and the like by the accelerated ions. Therefore, the mask for X-ray exposure having the above mixed layer can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a schematic sectional view partially showing an example of an X-ray exposure mask according to the present invention. 2 and 3 show
FIG. 3 is a schematic view showing an example of an apparatus for carrying out the manufacturing method according to the present invention. FIG. 4 is a graph showing an example of analytical data in the depth direction from the surface by Auger electron spectroscopy of the X-ray exposure mask obtained by the method of the example. FIG. 5 is a diagram showing an example of a manufacturing process of an X-ray exposure mask. 2 ... Mask support, 4 ... X-ray transparent support, 6 ...
X-ray absorber, 12 ... X-ray exposure mask according to the embodiment, 14
…… Mixed layer, 18 …… ion source, 20 …… ion, 22 …… vaporization source, 26 …… metal.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-57-59330 (JP, A) JP-A-57-160127 (JP, A) JP-A-60-176235 (JP, A)

Claims (3)

[Claims] 1. An X-ray exposure mask having an X-ray absorber, an X-ray transparent support that supports the X-ray absorber, and a mask support that supports the X-ray absorber. The substance forming the X-ray absorber and the substance forming the X-ray transparent support are mixed in the vicinity of the interface with the support, and the X-ray absorber is formed closer to the X-ray transmission support. An X-ray exposure mask, wherein a mixed layer is formed in which the ratio of the substance to be continuously reduced and the ratio of the substance to form the X-ray transparent support is continuously increased. 2. A mask support having an X-ray transparent support and an X-ray absorber formed thereon, respectively, is prepared, and the inertness is accelerated from the X-ray absorber side in vacuum. By injecting gas ions, the substance forming the X-ray absorber and the substance forming the X-ray transparent support are mixed in the vicinity of the interface between the X-ray absorber and the X-ray transparent support. In addition, the mixed layer in which the proportion of the substance forming the X-ray absorber is continuously decreased and the proportion of the substance forming the X-ray transparent support is continuously increased as the X-ray transparent support is approached. And a method for manufacturing an X-ray exposure mask. 3. A mask support having an X-ray transparent support formed thereon is prepared, and the X-ray absorber constituting metal is vapor-deposited on the X-ray transparent support in vacuum. By irradiating a metal ion of the same kind as the metal or an inert gas ion which has been accelerated, an X-ray absorber is provided on the X-ray transparent support, and an X-ray absorber near the interface between the two. And a substance forming the X-ray transparent support are mixed with each other, and the proportion of the substance forming the X-ray absorber continuously decreases as the X-ray transparent support approaches, and X A method for producing a mask for X-ray exposure, which comprises forming a mixed layer in which the ratio of substances constituting the radiation transparent support is continuously increased.