JPS63169026A - Mask structure for lithography - Google Patents

Abstract

PURPOSE:To perform an optical alignment by providing a thin film which mainly contains aluminum and nitrogen or a thin film made of a laminate containing mainly at least aluminum and nitrogen, and a patterned opening formed on the film as a high energy beam transmission section, thereby eliminating an intensity drop. CONSTITUTION:In a mask structure for a lithography made of a thin film in which a patterned opening is used as a high energy transmission section, the thin film is formed of a film containing mainly aluminum and nitrogen or a laminate containing a film mainly contains at least aluminum and nitrogen. The film in which the aluminum and the nitrogen are mainly contained includes a compound represented by AlN:O, AlN:H, AlN:O:H, AlN:C, AlN:C:O, etc. An inorganic material which forms a laminated layer film is exemplified by boron nitride, silicon oxide, etc. The organic material which forms the laminated layer film is, for example, polyimide, polyamide, etc. Thus, an optical alignment is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mask structure for lithography. More specifically, the present invention relates to a mask for high-energy beam lithography, and more particularly to a mask structure for lithography that uses patterned openings to allow high-energy beams to pass through and perform pattern transfer.

Note that usable high-energy beams include fixed targets (e.g., Pd, St, Mo, Rh, AU, W, Cu).
) etc. Wavelengths 4 to 13 Characteristic lines of people, plasma X-rays, SO
Examples include R-rays (X-rays to vacuum ultraviolet rays), deep ultraviolet rays, ultraviolet rays, ion beams, or electron beams.

[Prior Art] Lithography is a method of applying irradiation energy to a photosensitive material through a mask to project a pattern previously formed on the mask onto the photosensitive material.

Conventionally, masks for high-energy beam lithography have been obtained by patterning a high-energy beam absorber on a high-energy beam-transparent thin film.

[Problems to be Solved by the Invention] However, in the high-energy ray-transparent thin film, the absorption of high-energy rays is low, resulting in a decrease in the intensity of the high-energy rays.

On the other hand, the mask generates heat when irradiated with high-energy rays, causing distortion within the mask. Therefore, titanium (Ti), which has good thermal conductivity, has traditionally been used as the material for the film that makes up the mask.
, aluminum (AΩ), silicon nitride (SiN), silicon carbide (SiC), etc. have been proposed. but,
Since these are opaque, optical alignment is difficult.

The purpose of the present invention is to solve the above-mentioned problems in the conventional type.
It is an object of the present invention to provide a mask structure for lithography which is sufficiently good without any decrease in intensity even when high-energy rays are used as irradiation energy, and which also enables optical alignment.

[Means and Effects for Solving the Problems The purpose of the above is to provide a lithography mask structure consisting of a thin film in which patterned openings are high-energy ray transmitting portions, the thin film being mainly made of aluminum and nitrogen. This is achieved by a lithography mask structure characterized in that it is composed of a film containing a film containing aluminum or a laminate containing a film mainly containing at least aluminum and nitrogen.

Note that the film mainly composed of aluminum and nitrogen is AΩN:O
, AuN:H, AΩN:O:H, AUN:C, AdanN:
Compounds represented by C:0 etc. are also included.

The thin film in the mask structure of the present invention may be a single layer of a film mainly composed of aluminum and nitrogen, or a laminate of a film mainly composed of aluminum and nitrogen and other inorganic and/or organic materials. It could be something like that.

As the inorganic substance constituting the laminated film, one having at least film-forming properties can be used.

Examples of such inorganic substances include boron nitride, silicon oxide, silicon nitride, and silicon carbide.

As the organic substance constituting the laminated film, it is possible to use at least one having film-forming properties.

Examples of such organic materials include polyimide, polyamide, polyester, and Parylene (trade name, manufactured by Union Carbide).

The laminated film may consist of two or three layers of a film mainly composed of aluminum and nitrogen and an inorganic film and/or an organic film, or a film mainly composed of aluminum and nitrogen and an inorganic film and/or an organic film. Alternatively, it may be made up of three or more layers as a whole by using two or more layers of at least one of the organic material film and the organic material film.

The thickness of the thin film in the present invention is not particularly limited and can be set to an appropriate thickness, for example from 1 to 10 μm.
It is advantageous to set it to about m.

The mask structure of the present invention can be obtained by holding the peripheral portion of the above thin film with a suitable annular holding substrate. Examples of such a holding substrate include, but are not limited to, glass, silicon, quartz, phosphor bronze, brass, iron, nickel, and stainless steel.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

As shown in FIG. 1(a), PIQ liquid (polyimide precursor, manufactured by Hitachi Chemical) was spin-coded on one side of a circular silicon wafer 1 with a diameter of 50 to 350 cm.
Cure was carried out for 4 hours to form a polyimide film 2 with a thickness of 1.5 μm. Furthermore, P is applied on this polyimide film 2.
MMA (polymethyl methacrylate) film 3 with a thickness of 2.5μ
It was formed to a thickness of m and pre-baked.

Next, as shown in FIG. 1(b), the PMMA film 3
Electron beam lithography was performed on the material and patterning was performed.

Next, as shown in FIG. 1(C), the patterned silicon wafer 1 is set in a plasma CVD apparatus (manufactured by Nikkei Anelva Co., Ltd.), and the temperature of the silicon wafer is set to 2.
Keep it at 40℃ and add triethylaluminum (8Ω((:H)
aL) in ammonia (NH3) gas and hydrogen gas (gas flow rate 1 each) while bubbling hydrogen (H2) gas.
15CCM), a high frequency power of 13.56 MHz 4W, and an internal pressure of about ITorr, an aluminum nitride film with a thickness of about 2 μm was deposited on the polyimide film 2 by the plasma CVD method.
4 was formed. The film formation rate at this time was approximately 200 people/
The time required was approximately 1.5 hours.

Next, as shown in FIG. 1(d), the PMMA was removed using a PMMA removal solution to obtain an aluminum nitride pattern 4 on the polyimide film 2.

Next, as shown in Fig. 1(e), a ring frame (manufactured by Virex, inner diameter 7.5 cm
, outer diameter 9CI111 thickness 5mm) 5 was coated with an epoxy adhesive, and the surface of the aluminum nitride In14 was adhered to the adhesive coated surface.

Next, as shown in FIG. 1(f), cuts were made in the aluminum nitride film 4 and the polyimide film 2 along the outer periphery of the ring frame 5.

Next, as shown in FIG. 1(g), the silicon wafer 1 was separated and removed by applying ultrasonic waves in an aqueous solution containing a surfactant (sodium alkylbenzenesulfonate).

Next, as shown in FIG. 1(h), the polyimide film 2 was removed using a hydrazine solvent. During this solvent treatment, a tar-based paint was applied on the aluminum nitride film 4 to protect it, and after the polyimide film 2 was removed, the tar-based paint layer was removed with acetone.

In this way, a lithography mask structure was obtained, which consisted of a mask thin film made of aluminum nitride film 4 having patterned openings, and whose peripheral portion was held by a ring frame 5 serving as an annular holding substrate.

No pinholes were observed in the aluminum nitride film 4 of the mask structure obtained in this example, and it was confirmed that the internal stress was small.

Example 2 A polyimide film 7 is formed on a silicon wafer 6 in the same way as in Example 1.
was formed (Fig. 2(a)).

Next, as shown in FIG. 2(b), the silicon wafer 6 on which the polyimide film 7 was formed was set in a plasma CVD apparatus (manufactured by Nichiden Anelva), and the temperature of the silicon wafer was maintained at 250°C. , aluminum trichloride (AΩC
1,) in ammonia (NHa) gas and nitrogen gas (gas flow rate 1 each) while bubbling with nitrogen (N2) gas.
1511:CM), plasma CVD at a high frequency power of 13.56 MHz 20W and an internal pressure of approximately ITorr.
An aluminum nitride film 8 having a thickness of approximately 2 μm was formed on the polyimide film 7 by a method. Note that the film formation rate at this time was approximately 30
00 people/min, and the required time was about 7 minutes.

Next, as shown in FIG. 2(C), a layer 9 of EB resist CMS-EX (manufactured by Toyo Entatsu) is formed on the aluminum nitride film 8 to a thickness of about 1 μm, and a butter pattern is formed by electron beam drawing. I performed the ning.

Next, as shown in FIG. 2(d), the aluminum nitride film 8 is patterned using CCL gas or by active ion etching (RIE), and then the aluminum nitride film 8 is patterned using 0. R
CMS-EX was removed by IE.

Next, as shown in Fig. 2(e), a ring frame (manufactured by Pyrex, inner diameter 7.5 cm
An epoxy adhesive was applied to one side of the aluminum nitride film 8 (outer diameter 9 cm, thickness 5 mm) 10, and the surface of the aluminum nitride film 8 was adhered to the adhesive coated surface.

Next, as shown in FIG. 2(f), cuts were made in the aluminum nitride film 8 and the polyimide film 7 along the outer periphery of the ring frame 10.

Next, as shown in FIG. 2(g), the silicon wafer 6 was separated and removed by applying ultrasonic waves in an aqueous solution containing a surfactant (sodium alkylbenzenesulfonate).

Next, as shown in FIG. 2(h), the polyimide film 7 was removed using a hydrazine solvent. During this solvent treatment, a tar-based paint was applied on the aluminum nitride film 8 to protect it, and after the polyimide film 7 was removed, the tar-based paint layer was removed with acetone.

In this way, a lithography mask structure was obtained, which consisted of a mask thin film made of aluminum nitride film 8 having patterned openings, and whose peripheral portion was held by a ring frame 10 serving as an annular holding substrate.

[Effects of the Invention] According to the present invention as described above, the film mainly composed of aluminum and nitrogen used as the constituent elements of the mask has high visible light transmittance (optical density of about 0.1 μm thick).
), the coefficient of thermal expansion is low (3 to 4 x 10-'/l),
Since it has characteristics such as high thermal conductivity and good film formability, the following effects can be obtained.

(1) Since a film mainly composed of aluminum and nitrogen has a high transmittance of visible light, optical alignment can be easily performed.

(2) The thermal expansion coefficient of the film mainly composed of aluminum and nitrogen is the thermal expansion coefficient of the silicon wafer baked substrate (2 to 3
Since the value is almost the same as x 10-6/t), extremely high precision printing is possible.

(3) Due to the high thermal conductivity of the film mainly composed of aluminum and nitrogen, XIa is particularly suitable for high-energy rays such as SOR rays, high-energy rays such as ion beams for which transmission masks cannot be used, and high-energy rays such as plasma rays. It can prevent the temperature of the mask from rising due to energy ray irradiation, and is particularly effective when baking in a vacuum.

(4) X-ray exposure, especially X-ray exposure using long wavelength (λ = 20 to 200) X-rays, EB (electron beam) exposure and I
In B (ion beam) exposure, it is very difficult to obtain a material with high transmittance as a membrane, so the mask according to the present invention, which does not require a membrane, is effective.

[Brief explanation of the drawings] Figure 1 (a) to (h) and Figure 2 (a) to (h)
2A and 2B are diagrams illustrating the manufacturing process of a lithography mask structure according to the present invention. 1.6=silicon wafer, 2,7: polyimide film, 3
: PMMA film, 4.8 = aluminum nitride film, 5.1
0: Ring frame. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Tetsuya Ito (h) 4-layer Rororororo 411 Figure 1 (h) 4 Hearts Rorororo Monthly 28 Figure 2

Claims (1)

[Claims] 1. A thin film consisting of a thin film mainly composed of aluminum and nitrogen, or a laminate containing at least a film mainly composed of aluminum and nitrogen, and a pattern provided on the thin film as a high-energy ray transmitting part 1. A lithography mask structure having an opening. 2. The lithography mask structure according to claim 1, wherein the high-energy beam is an X-ray, an electron beam, a vacuum ultraviolet ray, or an ion beam.