JPS61194724A - Mask pattern adjustment and mask to be used therefor - Google Patents

Abstract

PURPOSE:To attempt the enhancement of precision in adjusting the coordinates of a pattern position and in lithographical overlapping by adjusting the stress appearing in the periphery of the mask pattern forming section made of thin film by a physical means. CONSTITUTION:A thin film 2 composed of boron nitride is adhered on the upper surface of a circular silicon frame 1. A central, square section of the film 2 constitutes the pattern forming section 2a on the surface of which a prescribed gold pattern is found, and the peripheral section surrounding the pattern forming section 2a constitutes a stress adjusting region 4 thinner than the most outside circumference. Fluid jackets 5 are installed at eight points, four corners of the pattern forming section 2a and four points close to the mid-points of each sides. In the jackets 5, fluid at a prescribed temperature is flown from the inlet opening 5a to the exit opening 5b to maintain the stress adjusting section 4 partially at a desired temperature, allowing the adjustment of expansion or shrinkage of constituent members. By this, strain occurring in the pattern forming section 2a is removed to enable exact adjustment of the coordinates of a pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to lithography technology, and in particular to X-ray masks.
This invention relates to pattern adjustment techniques for line lithography masks.

[Background technology]

With the miniaturization of circuit elements of pellets and the miniaturization of wiring applied to the circuit elements, the wavelength of resist exposure energy such as electromagnetic waves used in lithography technology also tends to become shorter.

One of these energies is so-called X-rays.

Since X-rays have extremely short wavelengths, they are suitable for fine exposure of resist films.

Incidentally, in order to expose the resist film in a predetermined pattern, a mask corresponding to the pattern is used.

When using the X-rays as an energy source, the pattern forming part of the mask applied thereto requires various conditions such as transparency to X-rays, flatness, and dimensional stability, so appropriate materials must be used. Must be formed with proper structure.

As the X-ray mask, for example, The 5ocie
ty of photo-optical In
As described in detail in Strumentation Engineers magazine, 1982, Vol. 333, P118-PI23, gold, which is an X-ray absorbing material, is deposited on the upper surface of a thin film made of an inorganic material, such as silicon, on the upper surface of a frame. There are some products in which a predetermined pattern is formed.

This X-ray mask has an extremely thin pattern (for example, several μm thick) formed on the top surface of a film made of boron nitride (BN), etc.; The mask pattern is formed by depositing gold by sputtering or the like, depositing gold on top of it in a predetermined pattern, and then etching away the silicon substrate from the back surface, which poses a problem in that the mask pattern is likely to be distorted.

In addition to the above-mentioned structural and manufacturing method reasons, distortions in actual mask patterns may also be caused by the temperature rise of the mask itself during X-ray exposure.

Therefore, with a mask in which the pattern forming part is formed of a thin film as described above, the positional coordinates of the pattern may be distorted during exposure, resulting in errors in lithography overlay, which may affect precision in microfabrication. The inventor has discovered that there is a problem.

[Purpose of the invention]

The object of the invention is to provide a mask especially XIl! i! The present invention relates to a pattern adjustment technique for a lithography mask, and an object of the present invention is to provide a technique effective for improving the accuracy of lithography techniques.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, for a mask in which the pattern forming part is formed of a thin film, by adjusting the stress around the pattern forming part by physical means, the strain in the pattern forming part can be adjusted and the pattern can be adjusted. ,
The above object is achieved because the accuracy of the positional coordinates of the pattern can be improved and the overlay accuracy of lithography can be improved.

[Example 1] FIG. 1 shows a cross-sectional view of an X-ray lithography mask according to Example 1 of the present invention taken along the I-■ section in FIG. FIG.

In the mask of Example 1, a thin film 2 made of boron nitride (BN) is deposited on the upper surface of a circular frame 1 made of silicon and has an almost inverted cross section, and a square nitride film 2 is formed in the center of the circular frame 1. A pattern forming part 2a consisting only of a thin film 2 of boron is formed by being held by the frame 1, and a predetermined pattern is formed with gold 3 on the upper surface of the pattern forming part 2a.

In the mask, a stress adjustment region 4 having a shape thinner than the outermost periphery is formed around the pattern forming part 2a, and a fluid jacket 5 made of copper, for example, is attached to the back surface of the region as a member having a temperature adjustment function with an adhesive (not shown). .) is attached.

As shown in FIG. 2, the fluid jackets 5 are independently attached at eight locations close to each corner and the center of each side of the pattern forming section 2a, and each jacket is capable of injecting fluid at a desired temperature. By guiding the pressure from the inlet 5a to the outlet 5b, a predetermined portion of the stress adjustment region can be maintained at a desired temperature.

In the mask of Example 1, by partially bringing the stress adjustment region 4 to a desired temperature, the degree of expansion or contraction of the members constituting the region 4 can be adjusted. The resulting distortion can be removed, and as a result, the position coordinates of the pattern can be adjusted accurately.

In adjusting the pattern, it is preferable to use the fluid jacket 5, which can easily adjust the temperature of each independent part to a desired temperature.

Moreover, by providing the jacket at the position shown in FIG. 2, pattern adjustment can be achieved rationally. That is, by setting each of the eight jackets 5 to a desired temperature, the strain can be adjusted in any direction of XY.

[Embodiment 2] Embodiment 2 relates to a method for adjusting a mask pattern, which is an embodiment of the present invention.

For example, in the mask shown in FIG.
A method in which a thin film portion on the back or top surface of the stress adjustment region 4 is coated with a desired amount of a desired amount of a low boiling point substance is then exposed to X-rays.

That is, when performing X-ray exposure using the mask, the temperature of the mask member increases with exposure, and the mask pattern may become distorted due to the temperature change.

In that case, by applying a low boiling point substance selected in consideration of the boiling point, latent heat of vaporization, etc. to the stress adjustment region of the mask, the stress adjustment region, which has a large influence on the mask member during exposure, especially on the pattern forming portion, can be reduced. It can also adjust the temperature of any place. Therefore, the adjustment of the mask pattern can be achieved in the same way as in the case of using the temperature adjustment member as in the first embodiment.

In addition, as the low boiling point substance, ascent and methanol, which have high volatility, as well as water, which has low volatility, can be used.

〔effect〕

(1) For a mask in which the pattern forming part is formed of a thin film, by adjusting the stress around the pattern forming part by physical means, it is possible to adjust the pattern by adjusting the strain in the pattern forming part. Therefore, the accuracy of the position coordinates of the pattern can be improved.

(2) The above-mentioned +11 can improve the overlay accuracy of lithography, so that it is possible to improve the degree of pellet integration.

(3) The above fi+ can prevent the generation of defective pellets for the same reason as in the above (2), so that an improvement in yield can be achieved.

(4) By adjusting the stress around the pattern forming portion by adjusting the temperature around the pattern, the pattern adjustment described in +11 above can be easily achieved.

(5) The temperature adjustment described in (4) above can be easily achieved by applying a low boiling point substance to the stress 1M node region around the pattern forming part and utilizing the cooling effect of the low boiling point substance during evaporation. .

(6) The temperature adjustment described in (4) above can be achieved by attaching a member having a temperature adjustment function around the pattern forming part.
easily achieved.

(7) By using a fluid jacket as the member in (6) above, a predetermined portion of the stress adjustment region can be maintained at a desired temperature, so that accurate pattern adjustment can be easily achieved.

(8) Forming eight of the members of (6) above, each provided close to each corner and the center of each side of the rectangular pattern forming section, and adjusting each member to a desired temperature. Accordingly, the distortion of the pattern forming portion can be rationally adjusted, and thus accurate pattern adjustment can be easily achieved.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

In the above embodiment, an example was shown in which a fluid jacket was used as a member having a temperature regulating function, but the present invention is not limited to this, and any member having a similar function may be used.

Further, although the fluid jacket has been described as having eight separate members, it is not limited thereto, and may be of an integral structure in which a fluid cavity is formed in a predetermined part, and the number of jackets or cavities is eight. It is not limited to individuals.

Furthermore, although the pattern forming portion of the mask is made of boron nitride, silicon nitride (Sf3N4), silicon carbide (S i C), silicon dioxide (SiO□), mylar, polyimide, or silicon (Si) may also be used. Alternatively, it may be formed into a multilayer structure of these and a resin such as polyimide.

It goes without saying that the structure of the mask is not limited to that shown in the above embodiments.

[Field of Application] In the above explanation, the invention made by the present inventor has mainly been explained in the field of application in which it is applied, which is to use X-rays or to masks for lithography, but the present invention is not limited thereto. For example, this technique is effective when applied to any mask that uses an ion beam or has a pattern forming portion formed of a thin film, such as a lithography mask.

[Brief explanation of the drawing]

FIG. 1 is a sectional view taken along section 1-1 in FIG. 2 showing an X-ray lithography mask according to Example 1 of the present invention. FIG. 2 is a back view showing the mask of Example 1. . DESCRIPTION OF SYMBOLS 1... Frame, 2... Thin film, 2a... Pattern forming part, 3... Gold, 4... Stress steel flff area, 5...
Fluid jacket, 5a...inlet, 5b...outlet.

Claims (1)

[Claims] 1. A stress adjusting region is provided around the pattern forming portion of a mask in which the pattern forming portion is formed of a thin film, and by adjusting the stress in the region, distortion occurring in the pattern forming portion is removed. How to adjust the mask pattern. 2. The method for adjusting a mask pattern according to claim 1, which comprises attaching a member having a temperature adjustment function to the stress adjustment region. 3. By applying an arbitrary low-boiling point substance to a desired part of the stress adjustment area and utilizing its latent heat of vaporization, the stress accompanying the temperature rise of the stress adjustment area is adjusted. The mask pattern adjustment method described in item 1. 4. The method for adjusting a mask pattern according to claim 2, wherein the member having a temperature regulating function is a fluid jacket. 5. The method for adjusting a mask pattern according to claim 1, wherein the thin film is formed of boron nitride, silicon nitride, silicon carbide, silicon dioxide, mylar, polyimide, or silicon. 6. A mask in which a stress adjusting section is provided at a predetermined portion around a pattern forming section formed of a thin film. 7. The mask according to claim 6, wherein the stress adjustment section is a temperature adjustment section. 8. The mask according to claim 7, wherein the temperature adjustment section is a fluid jacket. 9. The mask according to claim 7, wherein the temperature adjustment section is a plurality of independent members provided close to each corner and the center of each side of the rectangular pattern forming section. . 10. The mask according to claim 6, wherein the thin film is made of boron nitride, silicon nitride, silicon carbide, silicon dioxide, mylar, polyimide, or silicon.