Method for fabricating micro-lens, and micro-lens array including the micro-lens
View Patent ↗A micro-lens array and a method for fabricating a micro-lens includes forming a first lens formation material layer on and/or over a micro-lens formation area of a semiconductor substrate, and then forming a portion of the lens formation material layer as a first micro-lens using a first mask. A second lens formation material layer is formed adjacent to the first micro-lens on and/or over the micro-lens formation area. The second lens formation material layer is also formed as a second micro-lens using a second mask which is a different type from that of the first mask.
1. A method for fabricating a micro-lens, the method comprising;
forming a first photo-resist film on a micro-lens formation area of a semiconductor substrate;
forming the first photo-resist film as a first micro-lens using a first mask;
forming a second photo-resist film adjacent to the first micro-lens on the micro-lens formation area; and then
forming the second photo-resist film as a second micro-lens using a second mask,
wherein the first mask is formed with a transmission area allowing for a transmission of light to the first photo-resist film and a blocking area for blocking light,
wherein the blocking area is a gray dummy mask having gray dots,
wherein a density of the gray dots is determined so that the transmission of the light through the gray dots to portions therebelow is substantially prevented.
2. The method of claim 1 , wherein the first micro-lens is formed using a gray-tone mask as the first mask.
3. The method of claim 2 , wherein the second micro-lens is formed through a reflow process.
4. The method of claim 1 , wherein the density of the gray dots ranges from 60% to 80%.
5. The method of claim 4 , wherein the blocking area is formed of chromium.
6. The method of claim 5 , wherein the curvature radius of the first micro-lens is different from the curvature radius of the second micro-lens.
7. The method of claim 5 , wherein the curvature radius of a horizontal cut face and the curvature radius of a diagonal cut face of the first micro-lens are equal.
8. The method of claim 7 , wherein the height from a lower layer of the horizontal cut face and the height from a lower layer of the diagonal cut face are different from each other.
9. The method of claim 5 , wherein the first and second micro-lenses are formed to be adjacent in one of a vertical direction and a horizontal direction.
10. The method of claim 5 , further comprising:
forming a color filter array before forming the first photo-resist film.
11. The method of claim 5 , further comprising:
forming an over-coat layer before forming the first photo-resist film.
12. A micro-lens array for an image sensor, the micro-lens array comprising:
a first micro-lens having a first horizontal cut face and a first diagonal cut face;
a second micro-lens having a second horizontal cut face and a second diagonal cut face, the second micro-lens being adjacent to the first micro-lens and having a curvature radius different from the curvature radius of the first micro-lens,
wherein the height from a lower layer of the first horizontal cut face and the height from a lower layer of the first diagonal cut face are different from each other,
wherein the height from a lower layer of the second horizontal cut face and the height from a lower layer of the second diagonal cut face are equal,
wherein the first micro-lens is formed using a photo-resist folm and a mask, and the mask is formed with a transmission area allowing for a transmission of light and a blocking area for blocking light,
wherein the blocking area is a gray dummy mask having gray dots, and
wherein a density of the gray dots is determined so that the transmission of the light through the gray dots to portions therebelow is substantially prevented.
13. The micro-lens array of claim 12 , wherein the first micro-lens and the second micro-lens are formed to be adjacent in one of a vertical direction and a horizontal direction.
14. The micro-lens array of claim 13 , wherein the curvature radius of the first horizontal cut face and the curvature radius of the first diagonal cut face are equal.
15. The micro-lens array of claim 14 , wherein the curvature radius of the second horizontal cut face and the curvature radius of the second diagonal cut face are different from each other.
16. The micro-lens array of claim 15 , further comprising:
a color filter array formed under the first photo-resist film.
17. The micro-lens array of claim 15 , further comprising:
an over-coat layer formed under the first photo-resist film.