JPH06218321A - Removal of unnecessary part of film formed by rotary application - Google Patents

Abstract

PURPOSE:To provide a method of removing an unnecessary part, of a film formed by rotary application, which affects a high-accuracy thin film adversely in a following step using a simple device, in a short time and without giving any adverse effect to the part of the film other than the unnecessary part, regarding the high-accuracy thin film such as SOG to be used in a phase shift mask blank or a phase shift mask. CONSTITUTION:A decompression line end part (suction aperture) 3a where a solvent supply line end part 4a extends into the space of a decompression line 3 is allowed to get close to the film thickening part 2b. Next, the solvent is allowed to act on the solvent supply line 4 by decompressing the decompression line 3 to dissolve the film thickening part 2b. Further, the dissolved film thickening part 2b is sucked from the decompression line 3, and the unnecessary part of the film formed by rotary application is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing an unnecessary portion of a film formed by spin coating, and
Photomasks used for manufacturing high-density integrated circuits such as VLSI, coating films for LCD substrates, etc. Particularly, phase shift mask blanks and SOG coatings for phase shift masks used when forming fine patterns with high density. Effective for membranes.

[0002]

2. Description of the Related Art Photomasks used in the manufacture of high-density integrated circuits such as LSIs and VLSIs, coating films for LCD substrates, and phase shift mask blanks and phase shift masks used particularly when forming fine patterns with high density. The coating film of is formed by spin-coating a resist or SOG coating liquid on various substrates. The thin film formed by spin-coating is, for example, the outer periphery of the four corners or four sides of the rectangular substrate. A region where the film thickness is thicker than the film thickness in the central portion of the substrate is generated in a portion or the like.

These thickened regions are destroyed by the film stress of the thick film itself, cracks in the film progress from the outer peripheral portion of the substrate to the central portion, and film fragments are defective in the subsequent process. Can be a source of. Especially, SO
In the case of G, the cracks on the outer peripheral portion of the substrate easily spread to the central portion, and the film thickness control condition is, for example, 0.4 μm ± 10 nm.
The tolerance differs from the photoresist by ± 100 nm by about one digit, and the thick film region that has occurred must be immediately removed. Conventionally, in order to remove the unnecessary part of the film, the unnecessary part is removed by dipping it in a solvent, and a repellent material is previously formed on the lower part of the unnecessary part, and the unnecessary part of the film formed by spin coating is removed. A method of removing the unnecessary portion of the film formed by spin coating by applying a heat-melting material in advance below the unnecessary portion and removing it by heating is proposed, but further improvement is required. ing.

[0004]

SUMMARY OF THE INVENTION The present invention is a SOG used in a phase shift mask blank or a phase shift mask.
For high precision thin film such as, the unnecessary part of the film formed by spin coating, which has a bad effect in the subsequent process, is not affected at all in a short time by a simple device. Provide a way to effectively remove.

[0005]

The method of the present invention is a method for removing an unnecessary portion of a film formed by spin coating.
The step of bringing the depressurization line end (suction port) 3a provided with the solvent supply line end 4a in the space of the depressurization line 3 close to the thick film forming portion 2b of the substrate 1, and depressurizing the depressurization line 3 Removal of unnecessary portions of the film formed by spin coating, including a step of causing a solvent to act from the solvent supply line 4 to dissolve the thickened film thickening portion 2b and sucking the melted thickened film thickened portion 2b from the decompression line 3. Is the law. Further, in addition to the above steps, it is a method of removing an unnecessary portion of a film formed by spin coating, which includes a step of interrupting the supply of the solvent and removing the solvent on the surface of the substrate 1 through the decompression line 3. The present invention is particularly effective when the film formed by each spin coating is an SOG film applied to a phase shift mask or a phase shift mask blank.

The present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram for explaining the principle of the present invention, and shows an end portion of a substrate 1 formed by spin coating and provided with a thickened portion 2b continuous with a thin film portion 2a. The solvent supply line 4 extends from the solvent container into the space of the decompression line 3,
The decompression line 3 has a decompression line end (suction part) 3a. The decompression line 3 is connected to a vacuum pump via a trap.

FIG. 2 is a schematic diagram for explaining an example of the process of the present invention, which is an enlarged view of a portion surrounded by a dotted line in FIG. Figure 2
(a) shows a step of extending the solvent supply line end 4a into the space of the decompression line 4 and bringing the decompression line end (suction port) 3a closer to the thick film forming portion 2b. The inner diameter and material of the decompression line 3 and the solvent supply line 4 are changed depending on the region to be removed and the film quality. Also, the solvent used is
Starting with the solvent of the spin coating liquid, the optimum one is selected and used among the ones for dissolving the thick film forming portion 2b. Figure 2 (b) shows
The decompression start state in the decompression line 3 is shown.

FIG. 2 (c) shows that, as a result of decompression, air is sucked in between the substrate 1 and the decompression line end 3a, and at the same time, the solvent is jetted from the solvent supply line 4 to dissolve the thick film forming portion 2b. A state in which the melted thickened film portion 2b is sucked through the decompression line 3 is shown, and the space inside the decompression line 3 is depressurized below atmospheric pressure. Due to the decompression effect of the decompression line 3, the solvent and the like can be dissolved and sucked without leaking to the outside of the decompression line 3. The recovery is performed by providing a trap between the vacuum pump and the vacuum pump as shown in FIG. Then, the decompression line end (suction port) 3a is moved along the thickened film portion 2b to be removed. By moving the substrate 1 on the stage, processing can be performed more smoothly. FIG. 2 (d) shows a state in which the supply of the solvent is shut off by a valve, and the surface of the substrate 1 from which the thickened film portion 2b has been removed sucks in air due to the continuous depressurization effect of the depressurization line 3 and remains. The solvent can be dried.

[0009]

The following is an example of applying the method of the present invention to a method of removing an unnecessary portion of a film formed by spin coating of SOG in the manufacture of a halftone type phase shift photomask. An alumina film to be an etching stopper layer was formed on a quartz substrate. Next, Ac on the alumina film
cuglass-211S (made by Allied Signal Co., Ltd.)
The coated glass was spin coated.

Next, a method for removing unnecessary portions of the film formed by spin coating according to the present invention was performed. The solvent supply line end 4a with an inner diameter of 1.5 mm is extended into the space of the decompression line 3, and the decompression line end (suction port) 3a with an inner diameter of 5 mm is brought close to the space and slightly floated below 1 mm. Pressed against. The space inside the decompression line 3 has an atmospheric pressure of -600.
The pressure was reduced to about mmHg, and the solvent (acetone) was injected by the pressure reducing effect to dissolve the thickened portion 2b of SOG. The dissolved components, the solvent, and the like were sucked through the end (suction port) 3a of the depressurization line without leaking to the outside of the depressurization line 3, and were collected in a trap provided between the vacuum pump and the vacuum pump. While moving the depressurization line end (suction port) 3a along the thickened portion 2b around the quartz substrate, the above-mentioned work was continuously performed to completely remove the thickened portion. Then, the solvent supply on the solvent supply line 4 is shut off by a valve, and the solvent on the surface of the quartz substrate after removing the thickened portion 2b is removed by the decompression line 3
Breaked in more and dried. Then, it was baked at 200 ° C. to 500 ° C. to form a uniform transparent film for phase shifter only in the pattern region.

Next, the light transmittance on this film is 1% to 50%.
A chromium film was formed as a light-shielding layer by a sputtering method so that Next, SAL603 (Shipley Co., Ltd.) resist was spin-coated to a film thickness of about 500 nm. Next, alignment was performed according to a conventional method, and SAL603 was drawn by an electron beam exposure apparatus, developed, and rinsed to form a SAL603 resist pattern. Next, the chrome film exposed from the opening of the SAL603 resist pattern was removed with CCl ₄ + O ₂ ,
It was removed by reactive plasma etching using CH ₂ Cl ₂ + O ₂ or the like.

Further, the transparent film for the phase shifter in the pattern region exposed from the opening of the SAL603 resist pattern is removed by dry etching using CF ₄ , C ₂ F ₆ , CHF ₃ , CHF ₃ + O ₂ and a mixed gas thereof. Then, the remaining resist pattern was removed by ashing with oxygen plasma to complete a halftone phase shift photomask. The obtained phase shift photomask is SOG
There was no adverse effect due to cracks or the like in the thick film thickened portion.

[0013]

According to the present invention, in removing the unnecessary portion of the film formed by spin coating, compared to the conventional method of immersing the unnecessary portion of the film in a solvent or the method of removing the unnecessary portion with a solvent. The unnecessary thick film portion can be removed accurately and promptly without affecting the thin film portion. In particular, in the manufacturing process of the phase shift mask blank and the phase shift mask, it is possible to prevent frequent occurrence of defects due to chipping or cracking of the SOG thick film, and it is possible to shorten the manufacturing period and reduce the cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating the principle of the present invention.

FIG. 2 is a partially enlarged schematic view illustrating a process example of the present invention.

[Explanation of symbols]

 1 Substrate 2 Coating layer 2a Thin film part 2b Thickening part 3 Decompression line 3a Decompression line end (suction port) 4 Solvent supply line 4a Solvent supply line end

Claims (3)

[Claims] 1. A method of removing an unnecessary portion of a film formed by spin coating, wherein a solvent supply line end (4a) is provided in the space of a depressurization line (3) and a depressurization line end (suction port) ( 3a) is a thickened portion (2b) of the substrate (1)
And the pressure reducing line (3) is decompressed and the solvent is made to act from the solvent supply line (4) to dissolve the thickened portion (2b) and decompress the dissolved thickened portion (2b). A method of removing an unnecessary portion of a film formed by spin coating, including a step of sucking from a line (3). 2. Removal of an unnecessary portion of a film formed by spin coating according to claim 1, further comprising a step of interrupting the supply of the solvent to remove the solvent on the surface of the substrate (1) through a decompression line (3). Law. 3. The method for removing an unnecessary portion of a film formed by spin coating according to claim 1, wherein the material of the film formed by spin coating is SOG.