Light shield for pixel of image sensor

A method of manufacturing an image sensor, said method comprising:

• forming a photosensitive region for a pixel of the image sensor in a semiconductor substrate, said photosensitive region generating a photo-induced charge in response to illumination by light;
• forming a storage node for the pixel in the semiconductor substrate, said storage node selectively receiving the generated photo-induced charge from the photosensitive region created for the pixel;
• forming a transfer gate structure between the photosensitive region and the storage node to regulate a transfer of the photo-induced charge therebetween, the transfer gate structure having an upper end surface and a lower end surface covering at least a portion of the photosensitive region and the storage node;
• forming an inter-layer dielectric (ILD) over the transfer gate structure;
• and
• forming a substantially trapezoidal shaped light-shielding structure contained within the ILD and completely covering the upper end surface of the transfer gate structure, the light-shielding structure including a first end surface having a first width, a second end surface having a second width less than the first width, a first side wall extending from the upper end surface to the lower end surface, and a second side wall extending from the upper end surface to the lower end surface, and the light-shielding structure formed to include an indentation on the first end surface of the light-shielding structure, which first end surface is proximate to the upper end surface of said transfer gate structure, wherein the upper end surface of said transfer gate structure at least partially extends into said indentation such that the upper end surface of said transfer gate structure is at least partially surrounded by the indentation of the light-shield structure.

A method of manufacturing an image sensor, said method comprising:

• forming an array of active pixels, each active pixel having an associated photosensitive region and storage node disposed in a substrate;
• for each active pixel, forming a respective transfer gate structure disposed between the photosensitive region and the storage node, the respective transfer gate structure having an upper end surface and a lower end surface covering at least a portion of the photosensitive region and the storage node for each active pixel;
• forming an inter-layer dielectric (ILD) disposed over the respective transfer gate structures;
• and
• for each active pixel, forming a substantially trapezoidal shaped light-shielding structure contained within the ILD and completely covering the upper end surface of the respective transfer gate structure, the light-shielding structure formed to include a first end surface having a first width, a second end surface having a second width less than the first width, a first side wall extending from the upper end surface to the lower end surface, and a second side wall extending from the upper end surface to the lower end surface, and the light-shielding structure formed to include an indentation on the first end surface of the light-shielding structure, which first end surface is proximate to the upper end surface of said respective transfer gate structure, wherein the upper end surface of said respective transfer gate structure at least partially extends into said indentation such that the upper end surface of said respective transfer gate structure extending into said indentation is at least partially surrounded by the indentation of the light-shield structure.