JPS5891446A - Manufacture of film for soft x-ray lithography - Google Patents

Abstract

PURPOSE:To improve the strippability of a polyimide film formed on a glass substrate by applicating and hardening under heating by irradiating the film with ultraviolet rays. CONSTITUTION:A mask for soft X-ray lithography has an image pattern of Au, Pt or the like absorbing soft X-rays formed on a support film, and this invention relates to a method for using a polyimide film as the support film. A soln. prepared by dissolving polyamic acid as a precursor of polyimide in a solvent is applied to a glass substrate 1 and treated under heating to cause dehydration and ring closure. The resulting polyimide resin film 2 is uniformly irradiated with ultraviolet rays from the glass side or the film side. A support frame 5 of silicon or the like is stuck to the irradiated film 3 with an adhesive 6, and the film 3 is physically stripped. Thus, a uniform polyimide resin film is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides L81. The present invention relates to a method for manufacturing a mask film used in one step of soft X-ray lithography in manufacturing high-density integrated circuits such as VLSIs.

Conventionally, as a mask for soft X-ray phosphorography, a mask in which a soft xIl-absorbing image pattern of KAu, P-, etc. is formed on a soft X-ray transparent support film fixed to a support frame has been used. It's here. A silicon or glass substrate with a smooth surface is generally used as the support frame. Soft xma-permeable support film materials include inorganic materials such as silicon nitride and boronitride.
Support films made of thin films of materials or organic-like materials such as polyethylene terephthalate, polyimide, and polyvaraxyly V have advantages such as thermal stability and chemical resistance. It is thin at a few μm (it has the disadvantage of being extremely brittle and easily damaged).

On the other hand, polymer films such as polyethylene terephthalate and polyimide° have the advantage of being relatively strong and self-transparent to visible light; However, it is difficult to obtain a uniform thin film with a thickness of several μm, and these films often have fine racks on their surfaces. It is unsuitable as a film for soft X-ray lithography that forms fine **.

As an alternative method, the following method has conventionally been used. One is to deposit a polymer resin solution such as polyimide on a thin glass substrate with good flatness and a thickness of around 201) μm.
Co., Ltd.] After fabrication, heat curing to form a polymer film,
In this FF, since the polymer film is tightly adhered to the glass substrate, the glass substrate is first removed by etching with hydrofluoric acid to obtain a separated polymer film.

This method has the advantage of producing a film with a smooth surface, but since the glass substrate is thick (about JOOμm), it takes time to remove the etching, and the etching removal tends to be uneven, resulting in deformation of the film. This method has disadvantages such as easy occurrence of problems and the need for special manufacturing equipment.

Another method is to apply a release agent to the surface of a glass substrate and then form a polymer film.

Next, there is a method of physically peeling off the polymer film from the glass substrate. However, this method also uses a mold release agent, so #c
However, it has the disadvantage that the properties of the support film are deteriorated due to the am agent being included in the polymer film or the shape of the release agent being transferred to the polymer film.

Furthermore, another method is to form a thin film of metal such as aluminum or silver on a glass substrate, then form a polymer film thereon, and then remove the thin metal film by dissolving it with a chemical to form a polymer film. However, this method also requires an additional step of forming a thin metal film using specialized equipment such as vapor deposition or snobbing, and because the thin metal film is sandwiched between a glass substrate and a polymer film, The present invention eliminates the drawbacks of the above-mentioned conventional methods and provides a method for obtaining high-quality soft X-ray lithography films by an extremely easy method. The present invention focuses on the fact that a polyimide film, which is a polymer film coated on a glass substrate and cured by heating, sometimes tends to peel off after sputtering in an Ar gas atmosphere.
The reason for the improvement in peelability is (a) sputtering effect of argon ions (b) thermal movement in a braze atmosphere.
K. From the point of view of the ultraviolet light effect caused by the generation of lasma, as a result of extensive research into how the effect affects polyimide and the interface between polyimide and glass, we found that the effect of ultraviolet light affects the peelability of polyimide films. After seeing this, we investigated the conditions in detail and completed the present invention.

Hereinafter, the present invention will be explained in detail with reference to the drawings. Figure 1 is a T diagram showing the method of manufacturing a film for soft X-ray lithography according to the present invention, and the surface as shown in Figure 1 iml is smooth. on the glass substrate 111 [, polyimide resin 1!11
is applied and heated to cure to form a cured polyimide resin film (2) as shown in Figure 1 (bl).

In the above, as the polyimide resin, for example, polyimide constituted by imide bonds, polyamideimide constituted by amide bonds and imide bonds, and polyesterimide constituted by ester bonds and imide bonds, etc. are used.

The above-mentioned polyimide-based resin has an imide bond and is generally insoluble in solvents. Therefore, in order to provide a polyimide-based resin film on a substrate in the present invention, boric acid is dissolved in the solvent described below. After ICIJI cloth on the board 1,
Regarding heating, it is preferable to dehydrate and close the ring to form an i2 do bond.

Bo 17 of the precursor of polyamideimide 0 above
is synthesized by condensation of ogodiane obtained from excess diamine and dicarboxylic acid anhydride.

The polyamic acid, which is a precursor of the polyesterimide, is synthesized by the condensation of dicarboxylic anhydride having an ester group and sheagin. obtained from

Further, the polyamic acid, which is a precursor of the polyimide, is synthesized by condensation of a dicarboxylic acid and a diamine. These combination reactions were carried out under normal conditions.

-f, that is, carried out under anhydrous conditions at a temperature of 5 oct or lower.

The diamine mentioned above is, for example, m-phenylenedia t''*P-'enylene diamine.

Otori - xylene diamine, p-1 silene diamine, Tei -
Monodiaminodiphenyl ethers ”%”-diaminodiphenylmethane, 3.3”-dimethyl-tei, 411
-Cyaronodiphenylmethane, 3゜j', j, j''-
Tetramethyl-1,4E1-diaminodiphenylmethane, Co, Copis (4I-A2)ienyl)furopane, 411-Methylene dianiline, Benzidine @,
4+1-cyanodi7-denyl sulfide, tri-1-diaminodiphenylsulfone, t,z-cya-2-nonaphthalene, 31,71-dimethylbesizidine%3,31-dimethoxybenzidine, co-cubis(β-amino -t@r
t-butyl)toluene, bis(terβ-amino-t@r
t-”j tylphenyl) ether%/% Cubis (J
-methyl-tei-aminopentyl)benzene, etc. are used.

In the above diols, hydroquinone, bisphenol A, diquarbisphenol A, tetrachlorbisphenol A, tetrabromobisphenol A, bisphenol F, bisphenol ACP, bisphenol L, bisphenol V, bisphenol g, l, 41'-dihydrophenyl ether, etc. are used.

Moreover, as the dicarboxylic acid anhydride mentioned above, pimellitic anhydride, 2. J, &, Khunaphthalenetetracarboxylic anhydride, Js J', Reference s l'-diphenyltetracarboxylic anhydride, I% Co.

! , 1-naphthalenetetracarboxylic anhydride, J, J'
, J, J'-diphenyltetracarboxylic anhydride,
Thiophene, J, 41, j-tetracarboxylic anhydride% co, Corbis (3, derpicarboxyphene'
) 10271m hydrate s s % 41- dicarboxyphenylsulfone anhydride, perylene-J, 41. De, 10
-Tetracarboxylic acid I hydrate, bis('s, dicarpoxyf, enyl)ether anhydride, J, j', 1% 11
-benzophenone tetracarboxylic anhydride, etc. are used.

The above diamino, diol and dicarboxylic acid anhydride are all preferably aromatic compounds from the viewpoint of heat resistance.

To apply boriaelectric acid on a substrate, use dimethyl 7-olumamide, dimethylacetate, and 0.
．． Dimethylsulfonate.

Dissolved in a solvent such as N-methylpyrrolidone to form an aO/~30% solution, the S* can be self-applied by a brush coating method, a dipping method, a spinner coating method such as spinner coating, a spray @, etc. .

The coating film thickness is 1~! μm is tight. Heat curing conditions include pre-drying at 70 to 10 DC for 30 minutes as necessary, distilling off the solvent, and then heat-curing the polyimide resin film for 0 minutes at JOO~soC. . Next, the glass substrate (11) requires some flexibility during peeling, so the glass thickness is 1ooNjOO
As shown in Fig. 7, 1cl Vc, the heat-cured polyimide resin film (21) is irradiated with ultraviolet rays (4), for which μm is suitable. Light with a wavelength of 17 nm can be applied, and it is preferable to irradiate the entire surface from the glass side, but irradiation from the film side is also possible.The irradiation time depends on the wavelength used, intensity, and Although it varies slightly depending on the heat curing conditions, for example, when using ultraviolet rays with a continuous wavelength of 310 to 41 kOtsm and an irradiance of l!- (measured at *01v*m), an appropriate irradiation time of coo-41θ minutes is used. be.

Next, the polyimide resin was irradiated with ultraviolet rays. - By physically peeling off the film (31), a polyimide resin film for soft XLS masks with a smooth surface and sufficient tension without pinholes, cracks, or ridges can be obtained. Physically peeling the polyimide resin film For the purpose of peeling off, as shown in Figure A Il+, a supporting frame (51) made of silicone, etc., excluding the soft
It is desirable to obtain a uniform polyimide resin film as shown in Figure 1BL by physically peeling off the WC after bonding.

Furthermore, according to the present invention, after forming a soft XII-absorbing image pattern such as MuU on a film of a polyelectrode resin on a glass substrate, ultraviolet rays are irradiated and the first physical treatment is carried out. By peeling off the paper, the image pattern as shown in Figure 3 (7) is created.
It is also possible to obtain films with .

The present invention will be explained below with reference to Examples.

Example 1 N-/ on a glass substrate with a smooth surface and a thickness of 00 μm
Chirukobirolidone and Nd-dimethylacetamide! A solution of 3 polyimide resin precursors in a mixed solvent of 1:1 was applied using a spinner.

The mixture was dried at 90C and 30 molecules to obtain a uniform polyimide film with a thickness of 3 μm. Next 11c2! After curing the polyelectrode film by heating for rOc%Jo minutes, the film was exposed to irradiance/jp#M (41
t) jqm) irradiated with ultraviolet rays for 30 minutes,
A silicon support frame with a thickness of 300 μm with the soft X-ray transmitting portion removed in a circular shape is bonded to a Bolii Electron 0 film that has been irradiated with ultraviolet rays via an epoxy adhesive, and the film and silicone frame are firmly bonded with K11. urge

Next, physically peel off the polyimide from the edge of the glass.
A polyimide film with a uniform surface and a constant tension was obtained on the silicon frame.

Example In the same manner as in Example 1, a polyimide resin precursor solvent was applied on a glass substrate using a spinner and dried for 30 minutes to obtain a uniform polyimide film with a thickness of 8 μm. After curing the heated sheet metal film, A is applied onto the polyester film by vacuum deposition.
n was provided at a thickness of 8 of 3oooX. Photoresist AZ-IS on the next KAtt-! After applying rO with a spinner to the thickness of the present ooo Fine turns of the photoresist were obtained. Next, the film was sputter etched for 70 minutes using the photoresist as a mask using a pressure crab X/f'Torr, output 10 (N), and Ar gas. The photoresist was removed using a liquid to obtain a glass plate having a fine pattern of AI on the Boli2 film.Next, this film was exposed to a radiant intensity coating using an ultra-high pressure mercury lamp.
UV rays were irradiated for 10 minutes at Wld, c*01 mm). Next, the silicone support frame from which the effective pattern portion had been removed in a circular manner was bonded to the polyimide 0 film using a cyanoacrylate adhesive, thereby firmly adhering the film and the silicone support frame. Next, by physically peeling off the polyimide film from the glass end surface, a polyimide film having a fine pattern of KAu on a silicon frame, a smooth surface, and a constant tension was obtained.

[Brief explanation of drawings]

Figure 1 +11, lbl, Ic) shows the soft X according to the invention.
@ Figure 1 is a cross-sectional view schematically showing each step of the manufacturing method of a film for Lingraphie. FIG. 3 is a schematic cross-sectional view showing an example of a mask for soft XJI lithography obtained by the present invention. (11...Glass substrate (2)...00 Bolioid Z-based resin film (3) 0
...--Polyimide resin film irradiated with ultraviolet rays +41. @...Ultraviolet light (51.1...Support frame (6)...--Adhesive (7)...Mul Patent applicant Dai Nippon Printing Co., Ltd. Company agent Patent attorney Atsumi Konishi

Claims (1)

[Claims] A film for soft X-ray lithography is formed by forming a film of a polyelectrode resin on a glass substrate with a smooth surface, then irradiating the film with ultraviolet rays, and then separating the film from the substrate. Manufacturing method.