Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Patent
1989-03-17
1991-09-24
Robinson, Ellis P.
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
428 76, 428913, 428520, 428704, 428695, 4284111, 428901, 428 65, 428201, 428203, 428204, 428209, 430 4, 430 5, 430 6, 430 7, 430 3, 430320, 430321, B32B 904, H01L 2100
Patent
active
050512951
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to novel durable pattern forming materials. More particularly, it relates to a photo mask or a lith film provided with a protective film which has excellent mechanical, optical and chemical properties and which can be suitably used for exposure to form a pattern in making IC, printed circuits, hybrid IC, etc.
BACKGROUND OF THE INVENTION
Recently, remarkable progress has been made in the semiconductor industry, such as of LSI, and ultra LSI, and integration in semiconductor elements has been rushed into an era of megabit. Thus, fine processing of the order of submicron is being demanded.
In production of such semiconductor elements, so-called lithographic techniques are generally used, which comprise providing a photoresist layer on a substrate, such as a silicon wafer, then irradiating the photo resist layer, with an actinic ray, through a photo mask or lith film provided thereon with a pattern of the desired shape, and thereafter subjecting the layer to development treatment and etching treatment to form the pattern on the silicon wafer substrate or printed circuit.
Photo resists include two types; the negative type in which only the portion exposed to actinic ray is cured and the unexposed portion is dissolved out upon development; and the positive type in which only the portion exposed to actinic ray is dissolved out upon development, which is directly opposite to the negative type.
Generally, a protective film, for prevention of damage to the pattern and to impart durability, is used over the materials used for forming the pattern, such as a photo mask and lith film.
As a lith film provided with a protective film, there is known one which comprises a material such as a polyester film, provided with a pattern of the desired shape, on which is laminated an organic film, such as a polyester, through an adhesive.
However, such lith films having a protective film are inferior in durability because the protective film per se is readily marred. Besides, since the thickness of the film is about 10-20 .mu.m, when actinic rays are irradiated onto the photoresist layer through this lith film, deflection and scattering of the actinic ray can cause changes in the line width of the pattern and reduction in resolution. There are also photo masks and lith films free from lamination, but in this case, the pattern is uncovered and is readily subject to damage due to wear in operation.
The object of the present invention is to provide a pattern forming material having superior durability which is free from the defects of the conventional pattern forming material, such as photo mask and lith film provided with protective film, and which is provided with a protective film, which is excellent in mechanical, chemical and optical properties, by simple means without causing a reduction in resolution.
SUMMARY OF THE INVENTION
The inventors have made intensive research in an attempt to develop pattern forming materials, such as photo masks and lith films provided with a protective film, having the above mentioned excellent properties. As a result, it has been found that by using a curable compound as the material for the protective film, a protective film comprising the curable compound can be formed on a photo mask or lith film by a very simple means without deterioration of resolution; and the resulting protective film is excellent in mechanical, optical and chemical properties, and thus a pattern forming material of excellent durability can be produced. The present invention has been accomplished based on these findings.
DETAILED DESCRIPTION OF THE INVENTION
That is, according to the present invention, there is provided a durable pattern forming material, comprising a photo mask or lith film, provided with a pattern of desired shape, and a cured protective overlay film of a curable compound formed thereover.
The photo mask used in the pattern forming materials of the present invention is not critical and those which are ordinarily used for conventional photo masks, for example, glass or
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patent: 4145218 (1979-03-01), Habu et al.
patent: 4242491 (1980-12-01), Hergenrother et al.
patent: 4264531 (1951-04-01), Li et al.
patent: 4543319 (1985-09-01), Chao et al.
patent: 4735890 (1988-04-01), Nakane
Mori Shigeo
Yaguchi Atsunori
Idemitsu Petrochemical Company Limited
Robinson Ellis P.
Watkins III William P.
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