Photomask, manufacture of photomask, formation of pattern, manufacture of semiconductor device, and mask pattern design system

A method of forming a pattern comprising the steps of:

• (a) preparing a photomask, said photomask including a semitransparent area and a transparent area for at least exposure light, in which the phase angle of a light beam passing through said semitransparent area is different from the phase angle of a light beam passing through said transparent area substantially by 180.degree.,
• wherein a transparent auxiliary pattern having the same phase angle of a light beam passing therethrough as that of a light beam passing through said transparent area is disposed around a main pattern formed of said transparent area, and a distance D between the center or a desired center line of said main pattern and that of said auxiliary pattern satisfies the relationship of D =b.lambda./NAm , where NAm is a mask-side numerical aperture of a projection lens, .lambda. is a wavelength of exposure light, and <b>
• is a coefficient in the range of 1.35 <b.ltoreq.1.9;
• (b) exposing a thin film made of a photoresist formed on a substrate using said photomask by projection optics;
• and
• (c) forming a pattern by development.

A method of forming a pattern comprising the steps of:

• (a) preparing a photomask, said photomask including a semitransparent area and a transparent area for at least exposure light, in which the phase angle of a light beam passing through said semitransparent area is different from the phase angle of a light beam passing through said transparent area substantially by 180.degree.,
• wherein a transparent auxiliary pattern having the same phase angle of a light beam passing therethrough as that of a light beam passing through said transparent area is disposed around a main pattern formed of said transparent area, and said auxiliary pattern is provided on an area of said photomask corresponding to an area of the projected main pattern which is located outwardly from an intermediate point between a first sub-peak and a second sub-peak generated around said projected main pattern and inwardly from said second sub-peak;
• (b) exposing a thin film made of a photoresist formed on a substrate using said photomask by projection optics;
• and
• (c) forming a pattern by development.

A method of forming a pattern comprising the steps of:

• (a) preparing a photomask, said photomask including a semitransparent area and a transparent area for at least exposure light, in which the phase angle of a light beam passing through said semitransparent area is different from the phase angle of a light beam passing through said transparent area substantially by 180.degree.,
• wherein a transparent auxiliary pattern having the same phase angle of light as that of a main pattern is disposed at an area where an angle formed by intersections of desired two sides or extension lines thereof of said main pattern formed of said transparent area is less than 180.degree. in said semitransparent area;
• (b) exposing a photoresist formed on a substrate by projection optics using said photomask;
• and
• (c) forming a pattern by development.

A method of forming a pattern comprising the steps of:

• (a) preparing a photomask, said photomask including a semitransparent area and a transparent area for at least exposure light, in which the phase angle of a light beam passing through said semitransparent area is different from the phase angle of a light beam passing through said transparent area substantially by 180.degree.,
• wherein a transparent auxiliary pattern having the same phase angle of light as that of a main pattern and having a dimension being a resolution limit of projection optics or less is disposed at an area of said photomask corresponding to a position where interference light beams from different two sides of said main pattern formed of said transparent area overlap each other;
• (b) exposing a photoresist formed on a substrate by projection optics using said photomask;
• and
• (c) forming a pattern by development.

A method of forming a pattern comprising the steps of:

• (a) preparing a photomask, said photomask including a semitransparent area and a transparent area for at least exposure light, in which the phase angle of a light beam passing through said semitransparent area is different from the phase angle of a light beam passing through said transparent area substantially by 180.degree.,
• wherein at least two main patterns each being formed of said transparent area are disposed, and
• a transparent auxiliary pattern having the same phase angle of light as that of said main pattern and having a dimension being a resolution limit of projection optics or less is disposed at a position in which a distance S from the centers of said two main patterns satisfies the relationship of S=s.lambda./NAm, where NAm is a mask-side numerical aperture of a projection lens, .lambda. is a wavelength of exposure light, and <s>
• is a coefficient in the range of 0.8.ltoreq.s.ltoreq.1.1;
• (b) exposing a photoresist formed on a substrate by projection optics using said photomask;
• and
• (c) forming a pattern by development.

A method of forming a pattern comprising the steps of:

• (a) preparing a photomask, said photomask including a semitransparent area and a transparent area for at least exposure light, in which the phase angle of a light beam passing through said semitransparent area is different from the phase angle of a light beam passing through said transparent area substantially by 180.degree.,
• wherein at least two main patterns each being formed of said transparent area are disposed, and
• a transparent auxiliary pattern having the same phase angle of light as that of said main pattern and having a dimension being a resolution limit of projection optics or less is disposed at a position of said photomask corresponding to a position where first sub-peaks around main peaks of the projected main patterns are overlapped to each other;
• (b) exposing a photoresist formed on a substrate by projection optics using said photomask;
• and
• (c) forming a pattern by development.

A method of forming a pattern comprising the steps of:

• (a) preparing a photomask, said photomask including a semitransparent area and a transparent area for at least exposure light, in which the phase angle of a light beam passing through said semitransparent area is different from the phase angle of a light beam passing through said transparent area substantially by 180.degree.,
• wherein at least two main patterns each being formed of said transparent area are disposed, and
• a transparent auxiliary pattern having the same phase angle of light as that of said main pattern and having a dimension being a resolution limit of projection optics or less is disposed at a position of said photomask corresponding to a position where diffraction light beams from said main patterns are overlapped to each other at the same phase angle;
• (b) exposing a photoresist formed on a substrate by projection optics using said photomask;
• and
• (c) forming a pattern by development.

A method of forming a pattern of a photomask comprising a semitransparent area and a transparent area for at least exposure light, in which a phase angle of a light beam passing through said semitransparent area is different from a phase angle of a light beam passing through said transparent area substantially by 180.degree.,

• wherein a transparent auxiliary pattern having a same phase angle of a light beam passing therethrough as that of a light beam passing through said transparent area is disposed around a main pattern formed of said transparent area, comprising the steps of:
• (a) determining said auxiliary pattern of the photomask used for pattern printing by projection optics using a mask pattern design system, said process of determining said auxiliary pattern comprising the steps of:
• (1) calculating, on the basis of data of at least two of the main patterns formed in said photomask and parameters representing an optical condition of said projection optics, a light intensity distribution of a projected image of said main pattern obtained by said projection optics,
• (2) determining an area where a light intensity is more than a specified value, excluding an area corresponding to said main pattern, on the basis of said light intensity distribution of the projected image and said main patterns, and
• (3) determining one or a plurality of auxiliary patterns on an area of said photomask corresponding to said area where the light intensity is more than said specified value when said area is determined, and
• (b) forming said main pattern and said determined auxiliary patterns on said photomask;
• and
• (c) projecting and exposing a pattern by projection optics using said photomask formed with said main pattern and said determined auxiliary patterns.

A method of forming a pattern of a photomask comprising a semitransparent area and a transparent area for at least exposure light, in which the phase angle of a light beam passing through said semitransparent area is different from the phase angle of a light beam passing through said transparent area substantially by 180.degree.,

• wherein a transparent auxiliary pattern having the same phase angle of a light beam passing therethrough as that of a light beam passing through said transparent area is disposed around a main pattern formed of said transparent area, comprising the steps of:
• (a) determining said auxiliary pattern of the photomask used for pattern printing by projection optics using a mask pattern design system, said process of determining said auxiliary pattern comprising the steps of:
• (1) moving, on the basis of data of at least two of the main pattern forming said photomask, an contour line of each of said main patterns outwardly by a specified distance L, thereby determining the enlarged contour line of each of said main patterns,
• (2) detecting a position where said enlarged contour lines are close to each other at a specified distance M or less, and
• (3) determining one or a plurality of auxiliary patterns of a specified shape on said position where said enlarged contour lines are close to each other when said position is determined;
• and
• (b) forming said main pattern and said determined auxiliary pattern on said photomask;
• and
• (c) projecting and exposing a pattern by projection optics using said photomask formed with said main pattern and said determined auxiliary patterns.