US5418093A — Projection exposure method and an optical mask fo…

Claim 1

Independent Claim 134 words

A projection exposure method comprising the steps of: (a) irradiating a light from a light source on an optical mask, said optical mask including a main space which transmits light and has a desired exposure pattern, and a subspace which transmits light and is provided adjacent to the main space, wherein said step (a) irradiates the optical mask by the light from the light source with a predetermined oblique angle to a projection optical axis which is perpendicular to the optical mask; and (b) exposing a photoresist layer by the light which is transmitted through the optical mask and a lens so as to project an optical image of the main space, said subspace having a narrow width such that the light transmitted through the subspace by itself does not expose the photosensitive layer.

Claim 2

Dependent Claim 134 words

A projection exposure method comprising the steps of: (a) irradiating a light from a light source on an optical mask, said optical mask including a main space which transmits light and has a desired exposure pattern, and a subspace which transmits light and is provided adjacent to the main space, wherein said step (a) irradiates the optical mask by the light from the light source with a predetermined oblique angle to a projection optical axis which is perpendicular to the optical mask; and (b) exposing a photoresist layer by the light which is transmitted through the optical mask and a lens so as to project an optical image of the main space, said subspace having a narrow width such that the light transmitted through the subspace by itself does not expose the photosensitive layer.

Claim 3

Dependent Claim 52 words

The projection exposure method as claimed in claim 1, wherein said step (a) uses the light source selected from a group consisting of a light source which has a ring shape about the projection optical axis, and a light source which is arranged only on both sides of the projection optical axis.

Claim 4

Dependent Claim 68 words

The projection exposure method as claimed in claim 1, wherein said step (a) uses the optical mask in which a distance between center positions of the main space and the subspace is given by (λ/NA)×m×L, where λ denotes the wavelength of the light emitted from the light source, NA denotes the numerical aperture of the lens, 1/m denotes the reduced projection magnification, and L is 0.7 to 0.8.

Claim 5

Dependent Claim 34 words

The projection exposure method as claimed in claim 1, wherein said step (a) uses the optical mask in which the subspace is made up of at least a first subspace and a second subspace.

Claim 6

Dependent Claim 166 words

The projection exposure method as claimed in claim 4, wherein said step (a) uses the optical mask in which a distance d 1 between center positions of the main space and the first subspace is given by d 1 =D 1 ×m×(λ/NA), a distance d 2 between center positions of the main space and the second subspace is given by d 2 =D 2 ×m×(λ/NA), a width s of the main space is given by s=W×m×(λ/NA), a width s 1 of the first subspace is given by s 1 =W 1 ×m×(λ/NA), and a width s 2 of the second subspace is given by s 2 =W 2 ×m×(λ/NA), where λ denotes the wavelength of the light emitted from the light source, NA denotes the numerical aperture of the lens, 1/m denotes the reduced projection magnification, D 1 is 0.7 to 0.8, D 2 is 1.2 to 1.3, W is 0.3 to 0.4, W 1 is 0.2 to 0.3, and W 2 is 0.2 to 0.3.

Claim 7

Dependent Claim 48 words

The projection exposure method as claimed in claim 5, wherein said step (a) uses the light source which irradiates the optical mask with a predetermined angle δ to a projection optical axis which is perpendicular to the optical mask, and σ' is 0.6 to 0.7 when σ'=sinδ/(NA/m) .

Claim 8

Dependent Claim 116 words

A projection optical mask for an exposure system in which a light from a light source irradiates the projection optical mask adapted to receive the light from the light source at a predetermined oblique angle to a projection optical axis and in which an optical image transmitted through the projection optical mask is projected on a photoresist layer via a lens, said projection optical mask comprising: a main space which transmits light and has a desired exposure pattern; and at least one subspace which transmits light and is provided adjacent to the main space, said subspace having a narrow width such that the light transmitted through the subspace by itself does not expose the photosensitive layer.

Claim 9

Dependent Claim 116 words

A projection optical mask for an exposure system in which a light from a light source irradiates the projection optical mask adapted to receive the light from the light source at a predetermined oblique angle to a projection optical axis and in which an optical image transmitted through the projection optical mask is projected on a photoresist layer via a lens, said projection optical mask comprising: a main space which transmits light and has a desired exposure pattern; and at least one subspace which transmits light and is provided adjacent to the main space, said subspace having a narrow width such that the light transmitted through the subspace by itself does not expose the photosensitive layer.

Claim 10

Dependent Claim 60 words

The projection optical mask as claimed in claim 7, wherein a distance between center positions of the main space and the subspace is given by (λ/NA)×m ×L, where λ denotes the wavelength of the light emitted from the light source, NA denotes the numerical aperture of the lens, 1/m denotes the reduced projection magnification, and L is 0.7 to 0.8.

Claim 11

Dependent Claim 24 words

The projection optical mask as claimed in claim 7, wherein said projection optical mask comprises at least a first subspace and a second subspace.

Claim 12

Dependent Claim 157 words

The projection optical mask as claimed in claim 9, wherein a distance d 1 between center positions of the main space and the first subspace is given by d 1 =D 1 ×m×(λ/NA), a distance d 2 between center positions of the main space and the second subspace is given by d 2 =D 2 ×m×(λ/NA), a width s of the main space is given by s=W×m×(λ/NA), a width s 1 of the first subspace is given by s 1 =W 1 ×m×(λ/NA), and a width s 2 of the second subspace is given by s 2 =W 2 ×m×(λ/NA), where λ denotes the wavelength of the light emitted from the light source, NA denotes the numerical aperture of the lens, 1/m denotes the reduced projection magnification, D 1 is 0.7 to 0.8, D 2 is 1.2 to 1.3, W is 0.3 to 0.4, W 1 is 0.2 to 0.3, and W 2 is 0.2 to 0.3.

Claim 13

Dependent Claim 21 words

The projection optical mask as claimed in claim 7, wherein said subspace is provided on both sides .of said main space.

Claim 14

Dependent Claim 22 words

The projection optical mask as claimed in claim 7, wherein said subspace is provided on only one side of said main space.

Claim 15

Dependent Claim 51 words

The projection optical mask as claimed in claim 7, wherein said main space is a part of a line-and-space pattern and is provided at an end of the line-and-space pattern, and said subspace is provided on one side of the main space opposite to the side provided with the line-and-space pattern.

Claim 16

Dependent Claim 167 words

A projection exposure method comprising the steps of: (a) irradiating a light from a light source on an optical mask, said optical mask including a main space which transmits light and has a desired exposure pattern, and a subspace which transmits light and is provided adjacent to the main space, wherein said step (a) irradiates the optical mask by the light from the light source with a predetermined oblique angle to a projection optical axis which is perpendicular to the optical mask; and (b) exposing a photoresist layer by the light which is transmitted through the optical mask and a lens so as to project an optical image of the main space, said subspace having a narrow width such that the light transmitted through the subspace by itself does not expose the photosensitive layer, and said subspace being arranged adjacent to the main space so that the light transmitted through the subspace increases the peak intensity of the light transmitted through the main space on the photoresist.

Claim 17

Dependent Claim 167 words

A projection exposure method comprising the steps of: (a) irradiating a light from a light source on an optical mask, said optical mask including a main space which transmits light and has a desired exposure pattern, and a subspace which transmits light and is provided adjacent to the main space, wherein said step (a) irradiates the optical mask by the light from the light source with a predetermined oblique angle to a projection optical axis which is perpendicular to the optical mask; and (b) exposing a photoresist layer by the light which is transmitted through the optical mask and a lens so as to project an optical image of the main space, said subspace having a narrow width such that the light transmitted through the subspace by itself does not expose the photosensitive layer, and said subspace being arranged adjacent to the main space so that the light transmitted through the subspace increases the peak intensity of the light transmitted through the main space on the photoresist.

Claim 18

Dependent Claim 149 words

A projection optical mask for an exposure system in which a light from a light source irradiates the projection optical mask adapted to receive the light from the light source at a predetermined oblique angle to a projection optical axis and in which an optical image transmitted through the projection optical mask is projected on a photoresist layer via a lens, said projection optical mask comprising: a main space which transmits light and has a desired exposure pattern; and at least one subspace which transmits light and is provided adjacent to the main space, said subspace having a narrow width such that the light transmitted through the subspace by itself does not expose the photosensitive layer, and said subspace being arranged adjacent to the main space so that the light transmitted through the subspace increases the peak intensity of the light transmitted through the main space on the photoresist.

Claim 19

Dependent Claim 149 words

A projection optical mask for an exposure system in which a light from a light source irradiates the projection optical mask adapted to receive the light from the light source at a predetermined oblique angle to a projection optical axis and in which an optical image transmitted through the projection optical mask is projected on a photoresist layer via a lens, said projection optical mask comprising: a main space which transmits light and has a desired exposure pattern; and at least one subspace which transmits light and is provided adjacent to the main space, said subspace having a narrow width such that the light transmitted through the subspace by itself does not expose the photosensitive layer, and said subspace being arranged adjacent to the main space so that the light transmitted through the subspace increases the peak intensity of the light transmitted through the main space on the photoresist.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1998-05-22	1998-11-21	1999-05-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2002-05-22	2002-11-21	2003-05-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2006-05-22	2006-11-21	2007-05-23	$7700.00	Window Closed / Lapsed

Projection exposure method and an optical mask for use in projection exposure

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