Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Radiation mask
Reexamination Certificate
2000-05-24
2001-12-25
Rosasco, S. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
Radiation mask
Reexamination Certificate
active
06333130
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for correcting defects in a photomask, and more particularly to a method and an apparatus for correcting so-called clear defects in a photomask, which are defects formed by the loss of the light-shielding film of the photomask used in the manufacture of semiconductors or of liquid crystal displays.
2. Description of the Related Art
Conventional methods to correct clear defects in a photomask include a method to form a light-shielding film over clear defective parts of the photomask, which is disclosed in the Japanese Patent Laid-open No. 1989-124236. According to this conventional correcting method, a photomask is placed in an input gas atmosphere, and the input gas is locally decomposed on the photomask by irradiating the clear defective parts of the photomask with a laser beam to form a light-shielding film over the clear defective parts. In order to satisfy the requirements of tight adhesion to the substrate and light-shielding, both essential for a photomask, a metallic film of Cr or the like is deposited by laser chemical vapor deposition (CVD). This conventional correcting process uses as input gas a mixture of chrome carbonyl gas (Cr(CO)
6
) and argon gas, resulting in the formation of a film excelling in light-shielding and adhesion to the substrate.
Since this conventional clear defect correcting method for photomasks involves deposition of only a metallic light-shielding film over the substrate to correct clear defects, the reflectance of the light-shielding film deposited over the defective area is as high as about 40%. As a result, when the photomask is to be checked for any defect on the basis of the intensities of scatterred and reflected light from the substrate, the effect of light reflected from this light-shielding film having a high reflectance causes the previously defective parts already corrected by the deposition of the light-shielding film to be mistaken for uncorrected defects. At every step of inspection, these parts mistaken for defects have to be confirmed not to be defective, leading to a serious problem in the management of photomask manufacturing.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method and an apparatus for correcting defects in a photomask, capable of preventing defects which have been corrected by the deposition of a light-shielding film from being erroneously detected as uncorrected defects.
Another object of the invention is to provide a method and an apparatus for correcting defects in a photomask, capable of readily reducing the reflectance of previously defective parts corrected by the deposition of a light-shielding film.
In order to achieve the above-stated objects, a photomask defect correcting method according to the invention includes the deposition of a metallic first film so as to cover defective parts on a substrate where a light-shielding film has been lost, and then the deposition of a second film, whose reflectance is smaller than that of said first film, so as to cover the first film.
Another photomask defect correcting method according to the invention includes the deposition of a new metallic light-shielding film so as to cover defective parts on a substrate where a previous light-shielding film has been lost, and then the oxidation of the surface of said metallic light-shielding film to reduce the reflectance of its surface.
Furthermore, in order to achieve the above-stated objects, a photomask defect correcting apparatus is provided with a first gas feeding section for feeding organometallic input gas into a vessel in which a substrate is arranged; a second gas feeding section for feeding tetrakis dimethylamino titanium gas into the vessel in which said substrate is arranged; and a laser beam source for irradiating with a laser beam any desired position of the substrate arranged in said vessel when the atmosphere in said vessel consists of said input gas or said tetrakis dimethylamino titanium gas. Said second gas feeding section feeds tetrakis dimethylamino titanium gas into said vessel after the inside of said vessel is filled with said input gas atmosphere by the feeding of said input gas from said first gas feeding section and a metallic film is formed over said substrate by the irradiation of said substrate in said input gas atmosphere with a laser beam supplied from said laser beam source.
Another photomask defect correcting apparatus is provided with a first gas feeding section for feeding organometallic input gas into a vessel in which a substrate is arranged; a second gas feeding section for feeding ozone gas into the vessel in which said substrate is arranged; and a laser beam source for irradiating with a laser beam any desired position of the substrate arranged in said vessel when the atmosphere in said vessel consists of said input gas or said ozone gas. Said second gas feeding section feeds ozone gas into said vessel after the inside of said vessel is filled with said input gas atmosphere by the feeding of said input gas from said first gas feeding section and a metallic film is formed by the irradiation of said substrate in said input gas atmosphere with a laser beam supplied from said laser beam source.
REFERENCES:
patent: 4368230 (1983-01-01), Mizukami et al.
patent: 4440841 (1984-04-01), Tabuchi
patent: 4463073 (1984-07-01), Miyauchi et al.
patent: 4609566 (1986-09-01), Hongo et al.
patent: 4727234 (1988-02-01), Oprysko et al.
patent: 4778693 (1988-10-01), Drozdowizcz et al.
patent: 4806321 (1989-02-01), Nishizawa et al.
patent: 4975252 (1990-12-01), Nishizawa et al.
patent: 5014646 (1991-05-01), Ito et al.
patent: 5077100 (1991-12-01), Miracky
patent: 5130172 (1992-07-01), Hicks et al.
patent: 5276012 (1994-01-01), Ushida et al.
patent: 5292418 (1994-03-01), Morita et al.
patent: 5322988 (1994-06-01), Russell et al.
patent: 5472507 (1995-12-01), Yamaguchi et al.
patent: 5705235 (1998-01-01), Lehmann et al.
patent: 5780187 (1998-07-01), Pierrat
patent: 5885735 (1999-03-01), Imai et al.
patent: 5928817 (1999-07-01), Yan et al.
patent: 1-24236 (1989-05-01), None
NEC Corporation
Rosasco S.
Sughrue & Mion, PLLC
LandOfFree
Method and apparatus for correcting defects in photomask does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for correcting defects in photomask, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for correcting defects in photomask will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2571891