Photomask assembly, patterned mask and method for forming the same, and method for forming active region

Patent metadata

Field	Value
Publication number	US-12374550-B2
Application number	US-202117449458-A
Country	US
Kind code	B2
Filing date	Sep 30, 2021
Priority date	Mar 19, 2021
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

A photomask assembly includes: a first photomask for forming a first patterned structure, the first patterned structure having a first patterned opening which includes a plurality of strip-shaped patterns, a distance between the strip-shaped patterns at the two sides of a boundary between the first region and the second region being greater than a distance between other every two neighboring strip-shaped patterns when the center of the first photomask coincides with the center of the substrate; and a second photomask for forming a second patterned region which covers a first patterned opening of a second region, a distance between an opening edge of the second patterned structure and the neighboring strip-shaped pattern being greater than a first preset distance when the center of the second photomask and the center of the first photomask coincide with the center of the substrate.

First claim

What is claimed is:

1. A photomask assembly, configured to form a patterned mask on a substrate, the substrate having a first region, and a second region surrounding the first region, the photomask assembly comprising:
a first photomask, configured to form a first patterned structure on the substrate, the first patterned structure having a first patterned opening, the first patterned opening comprising a plurality of strip-shaped patterns, and a distance between the strip-shaped patterns at two sides of a boundary between the first region and the second region being greater than a distance between other every two neighboring strip-shaped patterns when a center of the first photomask coincides with a center of the substrate;
a second photomask, configured to form a second patterned region, the second patterned region being configured to cover the first patterned opening of the second region and having a second patterned opening, the second patterned opening being configured to expose the first patterned opening in the first region, and a distance between an opening edge of the second patterned structure and the neighboring strip-shaped pattern being greater than a first preset distance when a center of the second photomask and the center of the first photomask coincide with the center of the substrate; and
a third photomask, configured to form a third patterned structure, the first region comprising a first sub region and second sub regions, the second sub regions being positioned at two sides of the first sub region in an extending direction of the strip-shaped patterns, and the third patterned structure being formed in the first sub region, to cover the first patterned opening in the first sub region;
wherein the plurality of strip-shaped patterns are light shield strips extending along a second direction separated by light transmission portions;
wherein the second patterned opening is a rectangular light transmission portion surrounded by a light shielding portion;
wherein the first sub region being a rectangular light blocking region which has the same width in a first direction as the rectangular light transmission portion of the second photomask and a width in the second direction less than that of the rectangular light transmission portion of the second photomask and is surrounded by the second sub regions which are light transmission portions;
wherein the center of the first photomask, the center of the second photomask and a center of the third photomask coincide with the center of the substrate; and
wherein an open edge of the second patterned structure and an open edge of the third patterned structure are located between the strip-shaped patterns at the two sides of the boundary between the first region and the second region and the other strip-shaped patterns within the first region.

2. The photomask assembly of claim 1 , wherein when the center of the second photomask and the center of the first photomask coincide with the center of the substrate, distances between the opening edge of the second patterned structure and two neighboring strip-shaped patterns at two sides thereof are identical.

3. The photomask assembly of claim 1 , wherein when the center of the second photomask and a center of the third photomask coincide with the center of the substrate, a distance between the opening edge of the second patterned structure and the third patterned structure is smaller than a second preset distance in the extending direction of the strip-shaped patterns.

4. The photomask assembly of claim 1 , wherein the first photomask comprises a plurality of first shielding portions, the plurality of first shielding portions defining a light transmission region of the first photomask; the first photomask is configured to form a first patterned structure on the substrate through a multi-graphics forming method; and orthographic projections of the strip-shaped patterns on the substrate are positioned at two sides of orthographic projections of the first shielding portions on the substrate.

5. The photomask assembly of claim 4 , wherein each of the plurality of first shielding portions comprises first sub portions and second sub portions; when the center of the first photomask and the center of the substrate are superposed, the first sub portions are positioned in the first region, and the second sub portions are positioned in the second region; and a distance between neighboring first sub portion and second sub portion is greater than a distance between every two first sub portions, and is a greater than a distance between every two second sub portions.

6. The photomask assembly of claim 4 , wherein each of the plurality of first shielding portions comprises third sub portions and fourth sub portions, the third sub portions are positioned in the first region and the second region; in a direction perpendicular to the extending direction of the strip-shaped patterns, the fourth sub portions span between the first region and the second region, and a length of the fourth sub portions in the direction is greater than a distance between the fourth sub portions and neighboring the third sub portions.

7. The photomask assembly of claim 4 , wherein the first patterned opening has an annular shape, an orthographic projection of the first patterned opening on the substrate surrounds orthographic projections of the first shielding portions on the substrate; and the annular first patterned opening comprises two parallel and opposing strip-shaped patterns.

8. The photomask assembly of claim 1 , wherein
the first photomask includes a plurality of first shielding portions, the plurality of first shielding portions define a light transmission region of the first photomask, the portion on which the first light transmission region of the first photomask is located is the first light transmission portion;
the first photomask is matched with a positive photoresist, such that orthographic projections of the strip-shaped patterns on the substrate are positioned at two sides of orthographic projections of the first shielding portions on the substrate.

9. The photomask assembly of claim 1 , wherein
the first photomask includes a plurality of first shielding portions, the plurality of first shielding portions define a light transmission region of the first photomask, the portion on which the first light transmission region of the first photomask is located is the first light transmission portion;
the first photomask is matched with a negative photoresist, such that orthographic projections of the strip-shaped patterns on the substrate are positioned at two sides of orthographic projections of the first light transmission portion on the substrate.

10. The photomask assembly of claim 1 , wherein
the second photomask includes a plurality of second shielding portions and a plurality of second light transmission portions;
the second photomask is matched with a negative photoresist, the positions of the second light transmission portions of the second photomask are adjusted, so that the distance between an opening edge of the second patterned structure and the neighboring strip-shaped pattern being greater than a first preset distance.

11. A patterned mask forming method, comprising:
providing the photomask assembly of claim 1 ;
forming a first patterned structure on a substrate based on a first photomask, the first patterned structure having a first patterned opening, the first patterned opening comprising a plurality of strip-shaped patterns, the substrate having a first region, and a second region surrounding the first region, and a distance between the strip-shaped patterns at two sides of a boundary between the first region an

Assignees

• Changxin Memory Tech Inc

Inventors

• Chao Fufang
• Zhang Junjun
• Wu Zhimin

Classifications

• H10P76/4085 Primary

  characterised by the processes involved to create the masks · CPC title

• H10P76/4083

  characterised by their behaviours during the lithography processes, e.g. soluble masks or redeposited masks · CPC title

• H10W10/17

  formed using trench refilling with dielectric materials, e.g. shallow trench isolations · CPC title

• H10W10/014

  using trench refilling with dielectric materials, e.g. shallow trench isolations · CPC title

• H10P76/4088 Primary

  Processes for improving the resolution of the masks · CPC title