Shadow mask and manufacturing method thereof

1. A shadow mask, comprising:

a mask substrate;

a slit region formed by a first etching through the mask substrate using an etching mask, the slit region including etched side walls having a plurality of undercut portions, each undercut portion having a predetermined unit thickness so that the undercut portions have substantially the same thickness with each other; and

a shadow region provided in the mask substrate, the shadow region corresponding to a region other than the slit region,

wherein the slit region is further etched by a second etching performed after only regions under the etching mask are filled with photoresist, and

wherein the predetermined unit thickness of each of the undercut portions is about 2 to 15 micrometers.

2. The shadow mask according to claim 1 , wherein the mask substrate is made of iron or iron-nickel alloy.

3. The shadow mask according to claim 1 , wherein the mask substrate is about 30 to 300 micrometers thick.

4. A method of manufacturing a shadow mask, comprising:

forming a predetermined metal pattern on a mask substrate;

partially etching the mask substrate by a predetermined unit thickness using the predetermined metal pattern as an etching mask;

filling undercut portions formed during the step of partially etching the mask substrate with photoresist;

partially etching the partially etched portion of the mask substrate using the predetermined metal pattern as an etching mask after only regions under the etching mask are filled with the photoresist; and

repeating the steps of filling undercut portions formed during the step of partially etching the mask substrate with photoresist and partially etching the partially etched portion of the mask substrate using the predetermined metal pattern as an etching mask by a predetermined number of times until a slit region is completely formed so that the undercut portions have substantially the same thickness with each other,

wherein the predetermined unit thickness of the undercut portion is 2 to 15 micrometers.

5. The method according to claim 4 , further comprising removing the predetermined metal pattern by etching.

6. The method according to claim 4 , wherein the step of forming a predetermined metal pattern comprises:

depositing a metal material on the entire surface of the mask substrate;

coating the surface of the metal material with photoresist;

exposing and developing the photoresist, thereby forming a photoresist pattern corresponding to the metal pattern on the metal material; and

etching the metal material using the photoresist pattern as an etching mask, thereby forming the metal pattern.

7. The method according to claim 4 , wherein the slit region is made through a wet etching process.

8. The method according to claim 4 , wherein the predetermined number of times is determined according to desired precision of the metal pattern.

9. The method according to claim 4 , wherein the mask substrate is made of iron or iron-nickel alloy.

10. The method according to claim 4 , wherein the metal pattern is made of chrome.

11. The method according to claim 4 , wherein the mask substrate is about 30 to 300 micrometers in thickness.

12. The method according to claim 4 , wherein the undercut portion is formed because the mask substrate is etched isotropically in vertical direction and lateral direction.

13. A method of manufacturing a shadow mask, comprising:

forming a metal pattern in a shadow region on a metal mask including the shadow region and a slit region;

etching the metal mask in the slit region by a predetermined unit thickness using the metal pattern as an etching mask so that undercut portion are defined in the metal mask under edge portions of the metal pattern;

coating the entire surface of the metal mask with the metal pattern thereon with photoresist such that photoresist is deposited in the undercut portions;

exposing the photoresist such that the photoresist in the undercut portions is shielded by the metal pattern;

developing the photoresist on the metal mask, thereby maintaining the photoresist in the undercut portions;

forming a slit penetrating through the metal mask in the slit region by repeating the steps of etching the metal mask in the slit region by the predetermined unit thickness, coating the surface of the metal mask with photoresist, and filling undercut portions at respective sides of the slit region with the photoresist by a predetermined number of times so that the undercut portions have substantially the same thickness with each other; and

removing the metal pattern by etching,

wherein the size of the undercut portion is about 2 to 15 micrometers.

14. The method according to claim 13 , wherein the step of forming the metal pattern comprises:

depositing a metal material on the entire surface of the metal mask;

coating the surface of the metal material with photoresist;

exposing and developing the photoresist, thereby forming a photoresist pattern corresponding to the metal pattern on the metal material;

etching the metal material using the photoresist pattern as an etching mask, thereby forming the metal pattern.

15. The method according to claim 13 , wherein the slit region is formed through a wet etching process.

16. The method according to claim 13 , wherein the predetermined number of times is determined according to desired precision of the metal pattern.

17. The method according to claim 13 , wherein the metal mask is made of iron or iron-nickel alloy, and the metal pattern is made of chrome.

18. The method according to claim 13 , wherein the metal mask is about 30 to 300 micrometers in thickness, and the undercut portion is made by isotropically etching the metal mask in vertical direction and in lateral direction.