Method for Manufacturing Photomask and Photomask

Abstract

The application discloses a method for manufacturing a photomask, firstly determining a main pattern area of a photomask substrate and an auxiliary pattern area around the main pattern area; performing optical intensity simulation on patterns of the main pattern area and the auxiliary pattern area by means of an optical proximity correction (OPC) model, so as to ensure that the pattern of the auxiliary pattern area is not exposed on a photoresist on a wafer and the pattern of the main pattern area is exposed on the photoresist on the wafer during the integrated circuit manufacturing process; screening out a set of auxiliary pattern parameters; and forming the pattern of the main pattern area on the photomask substrate by means of a photomask manufacturing etching process, and forming the pattern of the auxiliary pattern area on the photomask substrate according to the auxiliary pattern parameters. The application also discloses a photomask.

Claims

1. A method for manufacturing a photomask, comprising the following steps: step 1, determining a main pattern area of a photomask substrate, and determining an auxiliary pattern area on the photomask substrate around the main pattern area; step 2, performing optical intensity simulation on patterns of the main pattern area and the auxiliary pattern area by means of an optical proximity correction (OPC) model, so as to ensure that the pattern of the auxiliary pattern area is not exposed on a photoresist on a wafer during an integrated circuit manufacturing process and ensure that the pattern of the main pattern area is exposed on the photoresist on the wafer during the integrated circuit manufacturing process; step 3, screening out a set of parameters of auxiliary pattern dimensions; and step 4, forming the pattern of the main pattern area on the photomask substrate by means of a photomask manufacturing etching process, and forming the pattern of the auxiliary pattern area on the photomask substrate according to the auxiliary pattern parameters.

2. The method for manufacturing the photomask according to claim 1, wherein: in step 3, according to a principle of ensuring that the main pattern formed in the main pattern area of the photomask substrate is safest, the set of auxiliary pattern parameters are screened out.

3. The method for manufacturing the photomask according to claim 2, wherein: in step 3, for a case where a pattern area has a dark tone in a negative tone develop process, when an intensity of light causes formation of the main pattern in the main pattern area of the photomask substrate and makes Lh−Ls Largest, the main pattern formed in the main pattern area of the photomask substrate is safest, wherein Lh is a critical threshold of optical intensity required to form exactly target critical dimensions of main pattern during exposure, and Ls is the intensity of light irradiating the auxiliary pattern area of the photomask substrate.

4. The method for manufacturing the photomask according to claim 1, wherein: in step 4, an OPC recipe is optimized, then the pattern of the main pattern area is formed on the photomask substrate by means of the photomask manufacturing etching process, and the pattern of the auxiliary pattern area is formed on the photomask substrate according to the auxiliary pattern parameters.

5. The method for manufacturing the photomask according to claim 1, wherein: the set of auxiliary pattern parameters comprise a length of a line pattern of the auxiliary pattern area, a width of the line pattern, an interval between the line patterns in a length direction, and an interval between the line patterns in a width direction.

6. The method for manufacturing the photomask according to claim 1, wherein: a direction of a line pattern of the auxiliary pattern area is perpendicular to the direction of a line pattern of the main pattern area.

7. The method for manufacturing the photomask according to claim 1, wherein: a critical dimension of the auxiliary pattern area is less than ⅓ of a critical dimension of the main pattern area.

8. The method for manufacturing the photomask according to claim 1, wherein: the auxiliary pattern area is rectangular, and a length and width thereof both exceed 20 times a critical dimension X of the pattern of the main pattern area.

9. The method for manufacturing the photomask according to claim 1, wherein: an interval between the auxiliary pattern area and the main pattern area is 5-10 times a critical dimension X of the pattern of the main pattern area.

10. The method for manufacturing the photomask according to claim 1, wherein: a critical dimension of the main pattern area is 35 nm-80 nm; a critical dimension of the auxiliary pattern area is 10 nm-20 nm; and an interval between the auxiliary pattern area and the main pattern area is 180 nm-300 nm.

11. The method for manufacturing the photomask according to claim 1, wherein: a length*width of a line pattern of the auxiliary pattern area is 10 nm*150 nm, 15 nm*300 nm, or 20 nm*150 nm.

12. A photomask manufactured by the method for manufacturing according to claim 1, wherein: the photomask comprises a main pattern area and an auxiliary pattern area; the auxiliary pattern area is located around the main pattern area; a critical dimension of a pattern of the auxiliary pattern area is less than a critical dimension of a pattern of the main pattern area; the pattern of the main pattern area can be transferred to a photoresist on a wafer during an integrated circuit manufacturing process; and the pattern of the auxiliary pattern area cannot be transferred to the photoresist on the wafer during the integrated circuit manufacturing process.

13. The photomask according to claim 12, wherein: the critical dimension of the auxiliary pattern area is less than ⅓ of the critical dimension of the main pattern area.

14. The photomask according to claim 12, wherein: a direction of a line pattern of the auxiliary pattern area is perpendicular to a direction of a line pattern of the main pattern area.

15. The photomask according to claim 12, wherein: the auxiliary pattern area is rectangular, and a length and width thereof both exceed 20 times the critical dimension X of the pattern of the main pattern area.

16. The photomask according to claim 12, wherein: an interval between the auxiliary pattern area and the main pattern area is 5-10 times the critical dimension X of the pattern of the main pattern area.

17. The photomask according to claim 12, wherein: the critical dimension of the main pattern area is 35 nm-80 nm; the critical dimension of the auxiliary pattern area is 10 nm-20 nm; an interval between the auxiliary pattern area and the main pattern area is 180 nm-300 nm; and a line pattern of the auxiliary pattern area is 10 nm*150 nm, 15 nm*300 nm, or 20 nm*150 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly explain the technical solutions of the present application, the drawings required by present application are briefly described below. It is obvious that the drawings described below are merely some embodiments of the present application, and those skilled in the art could also obtain other drawings on the basis of these drawings, without involving any inventive skill.

[0041] FIG. 1 is a schematic diagram of microloading.

[0042] FIG. 2 is a flowchart of a method for manufacturing a photomask according to an embodiment of the present application.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0043] The technical solutions of the present application will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of them. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without involving any inventive skill shall fall into the protection scope of the present application.

Embodiment 1

[0044] Referring to FIG. 2, a method for manufacturing a photomask includes the following steps:

[0045] Step 1. A main pattern area of a photomask substrate is determined, and an auxiliary pattern area on the photomask substrate is determined around the main pattern area.

[0046] Step 2. Optical intensity simulation is performed on patterns of the main pattern area and the auxiliary pattern area by means of an OPC (optical proximity correction) model, so as to ensure that the pattern of the auxiliary pattern area is not exposed on a photoresist on a wafer during an integrated circuit manufacturing process and ensure that the pattern of the main pattern area is exposed on the photoresist on the wafer during the integrated circuit manufacturing process.

[0047] Step 3. A set of parameters of auxiliary pattern dimensions are screened out.

[0048] Step 4. The pattern of the main pattern area is formed on the photomask substrate by means of a photomask manufacturing etching process, and the pattern of the auxiliary pattern area is formed on the photomask substrate according to the auxiliary pattern parameters.

[0049] In some examples, in step 3, according to a principle of ensuring that the main pattern formed in the main pattern area of the photomask substrate is safest (for a case where a pattern area has a dark tone in a negative tone develop (NTD) process, when the intensity of light causes the formation of the main pattern in the main pattern area of the photomask substrate and makes Lh-Ls Largest, the main pattern in the main pattern area of the photomask substrate is safest, wherein Lh is a critical threshold of optical intensity required to form exactly target critical dimensions of main pattern during exposure, and Ls is the intensity of light irradiating the auxiliary pattern area of the photomask substrate), the set of auxiliary pattern parameters are screened out.

[0050] In some examples, in step 4, an OPC recipe is optimized, then the pattern of the main pattern area is formed on the photomask substrate by means of the photomask manufacturing etching process, and the pattern of the auxiliary pattern area is formed on the photomask substrate according to the auxiliary pattern parameters.

[0051] In the method for manufacturing a photomask of embodiment 1, the auxiliary pattern area is designed in a large area around the main pattern area of the photomask substrate that does not require pattern transfer. A series of micro-dimension patterns are designed in the auxiliary pattern area to alleviate the loading effect of photomask manufacturing etching process, so as to achieve the critical dimension uniformity (CD uniformity) of patterns at different positions of the main pattern area on the photomask. Compared with a method of relying solely on photomask manufacturers adjusting the manufacturing etching process in the development stage, the method for manufacturing a photomask of embodiment 1 can more efficiently improve the critical dimension uniformity of patterns at different positions of the main pattern area on the photomask.

Embodiment 2

[0052] Based on the method for manufacturing a photomask of embodiment 1, the set of auxiliary pattern parameters include the length of a line pattern of the auxiliary pattern area, the width of the line pattern, an interval between the line patterns in the length direction, and an interval between the line patterns in the width direction, etc.

Embodiment 3

[0053] Based on the method for manufacturing a photomask of embodiment 1, the direction of a line pattern of the auxiliary pattern area is perpendicular to the direction of a line pattern of the main pattern area.

[0054] As the direction of the line pattern of the auxiliary pattern area is perpendicular to the direction of the line pattern of the main pattern area, so as to more effectively avoid an increase in the dimension of the pattern of the main pattern area adjacent to the auxiliary pattern area (non-pattern area) during exposure with laser beams (electron beams) and etching for forming a pattern on the photomask, thereby better improving the critical dimension uniformity of patterns at different positions of the main pattern area on the photomask.

Embodiment 4

[0055] Based on the method for manufacturing a photomask of embodiment 1, the critical dimension of the auxiliary pattern area is less than ⅓ of the critical dimension of the main pattern area.

Embodiment 5

[0056] Based on the method for manufacturing a photomask of embodiment 1, the auxiliary pattern area is rectangular, and the length and width thereof both exceed 20 times the critical dimension X of the pattern of the main pattern area.

[0057] In some examples, an interval between the auxiliary pattern area and the main pattern area is 5-10 times the critical dimension X of the pattern of the main pattern area.

[0058] In some examples, the critical dimension of the main pattern area is 35 nm-80 nm;

[0059] the critical dimension of the auxiliary pattern area is 10 nm-20 nm; and

[0060] an interval between the auxiliary pattern area and the main pattern area is 180 nm-300 nm.

[0061] In some examples, the length*width of a line pattern of the auxiliary pattern area is 10 nm*150 nm, 15 nm*300 nm, or 20 nm*150 nm.

Embodiment 6

[0062] A photomask manufactured by the manufacturing method of embodiment 1 or 2 includes a main pattern area and an auxiliary pattern area.

[0063] The auxiliary pattern area is located around the main pattern area.

[0064] The critical dimension of a pattern of the auxiliary pattern area is less than the critical dimension of a pattern of the main pattern area.

[0065] The pattern of the main pattern area can be transferred to a photoresist on a wafer during an integrated circuit manufacturing process.

[0066] The pattern of the auxiliary pattern area cannot be transferred to the photoresist on the wafer during the integrated circuit manufacturing process.

[0067] In the photomask of embodiment 6, not only the main pattern area with the pattern that can be transferred to the photoresist on the wafer during the integrated circuit manufacturing process is designed, the auxiliary pattern area with the pattern that cannot be transferred to the photoresist on the wafer during the integrated circuit manufacturing process is also designed on the side of the main pattern area, so that micro patterns are formed in the area with relatively low pattern density on the photomask, increasing the pattern density of the area on the periphery of the main pattern area. Therefore, during the photomask manufacturing etching process for manufacturing the photomask, the loading effect of the photomask manufacturing etching process can be alleviated. Under the premise of ensuring that the auxiliary pattern area will not be exposed on the photoresist on the wafer, the uniformity of patterns at different positions of the main pattern area on the photomask is improved, achieving the critical dimension uniformity (CD uniformity) of the main pattern area of the photomask, and thereby solving the problem of a difficult photomask manufacturing process under the small node (small critical dimension).

Embodiment 7

[0068] Based on the photomask of embodiment 6, the direction of a line pattern of the auxiliary pattern area is perpendicular to the direction of a line pattern of the main pattern area.

[0069] In some examples, the critical dimension of the auxiliary pattern area is less than ⅓ of the critical dimension of the main pattern area.

[0070] In some examples, the auxiliary pattern area is rectangular, and the length and width thereof both exceed 20 times the critical dimension X of the pattern of the main pattern area.

[0071] In some examples, an interval between the auxiliary pattern area and the main pattern area is 5-10 times the critical dimension X of the pattern of the main pattern area.

[0072] In some examples, the critical dimension of the main pattern area is 35 nm-80 nm.

[0073] The critical dimension of the auxiliary pattern area is 10 nm-20 nm.

[0074] An interval between the auxiliary pattern area and the main pattern area is 180 nm-300 nm.

[0075] A line pattern of the auxiliary pattern area is 10 nm*150 nm, 15 nm*300 nm, or 20 nm*150 nm.

[0076] Only some embodiments of the present application are described above, and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.