Image sensor light shield
A structure and method of reducing optical cross talk in an image sensor by using a light shield having light shield portions comprising a plurality of separated blocks of opaque material above each pixel cell's photosensor. The light shield portions have an aperture allowing light to pass through to the photosensor associated with the pixel cell. The blocks are separated from each other by a distance shorter than the wavelength of visible light; as such, the space created between the blocks mitigates the passing of wavelengths of incident light therethrough to undesired areas.
1 . An image sensor, comprising:
a photosensor supported on a substrate; and
a light shield comprising a plurality of opaque material blocks associated with and formed above the photosensor, a portion of the plurality of material blocks being arranged to define a light blocking area, the material blocks being separated in the light blocking area by a distance, the distance being less than or equal to the wavelengths of incident light.
2 . The image sensor according to claim 1 , wherein the distance is less than or equal to about 0.4 um.
3 . The image sensor according to claim 1 , wherein the distance prevents at least a portion of wavelengths of incident light from passing therethrough.
4 . The image sensor according to claim 1 , wherein the material blocks comprise a metal material.
5 . The image sensor according to claim 1 , wherein the material blocks are of a thickness and material so as to allow less than 1% of incident light to pass therethrough.
6 . An image sensor, comprising:
a photosensor supported on a substrate; and
a light shield comprising a plurality of metal material blocks associated with and formed above the photosensor, the material blocks being arranged to define a light blocking area, the material blocks being arranged in the light blocking area to be separated by a first distance, the first distance which prevents at least a portion of wavelengths of incident light from passing therethrough, and a light transmission area over the photosensor, the material blocks being arranged in the light transmission area to be separated by a second distance, the second distance allowing light to pass through to the photosensor.
7 . The image sensor according to claim 6 , wherein the first distance is less than or equal to the wavelengths of incident light.
8 . The image sensor according to claim 6 , wherein the first distance is less than or equal to about 0.4 um.
9 . The image sensor according to claim 6 , wherein the material block is of a thickness and material so as to allow less than 1% of incident light to pass therethrough.
10 . An image sensor, comprising:
a photosensor supported on a substrate; and
a light shield comprising a plurality of opaque material blocks associated with and formed above the photosensor, the material blocks being arranged to define a light transmission area over the photosensor to allow light to pass through to the photosensor, and a light blocking area, the material blocks being arranged in the light blocking area to be separated by a first distance, the first distance being less than or equal to the wavelengths of incident light.
11 . The image sensor according to claim 10 , wherein the first distance is less than or equal to about 0.4 um.
12 . The image sensor according to claim 10 , wherein the first distance prevents at least a portion of wavelengths of incident light from passing therethrough.
13 . The image sensor according to claim 10 , wherein a portion of the material blocks is separated by a second distance, the second distance providing the light transmission area.
14 . The image sensor according to claim 10 , wherein the material blocks are isolated from and provide no electrical contact to a conductive interconnect layer of the image sensor.
15 . The image sensor according to claim 10 , wherein at least one of the plurality of material blocks has electrical contact with a conductive interconnect layer of the image sensor.
16 . The image sensor according to claim 10 , wherein the material blocks comprise a metal material.
17 . The image sensor according to claim 10 , wherein the material blocks comprise a material selected from the group consisting of tungsten, tungsten silicide, titanium, titanium nitride, cobalt, chromium, polysilicon-tungsten silicide, aluminum, titanium silicide, molybdenum, tantalum and combinations thereof.
18 . The image sensor according to claim 10 , wherein the material blocks are about 100 Å to about 3,000 Å thick.
19 . The image sensor according to claim 10 , wherein the material blocks are of a thickness and material so as to allow less than 1% of incident light to pass therethrough.
20 . An image sensor, comprising:
an array contacting a plurality of pixel cells, each pixel cell having a photosensor; and
a plurality of separated opaque material blocks arranged above the pixel cells of the array,
wherein the material blocks are arranged to define an aperture over the photosensor to allow light to pass through to the photosensors of the pixel cells, and to define a light blocking area, the material blocks being arranged in the light blocking area to be separated by a first distance, the first distance being less than or equal to the wavelengths of incident light.
21 . The image sensor according to claim 20 , wherein the first distance is less than or equal to about 0.4 um.
22 . The image sensor according to claim 20 , wherein the first distance prevents at least a portion of wavelengths of incident light from passing therethrough.
23 . The image sensor according to claim 20 , wherein the material blocks comprise a metal material.
24 . The image sensor according to claim 20 , wherein the material blocks are of a thickness and material so as to allow less than 1% of incident light to pass therethrough.
25 . An image sensor system, comprising:
a processor;
an image sensor communicating with the processor, the image sensor comprising:
a pixel cell array having a plurality of pixel cells, each of the pixel cells comprising a photosensor supported on a substrate;
a conductive interconnect layer formed above the photosensor; and
a light shield comprising a plurality of opaque material blocks associated with and formed above the photosensor, the material blocks being arranged to define a light transmission area over the photosensor to allow light to pass through to the photosensor, and to define a light blocking area, the material blocks being arranged in the light blocking area to be separated by a first distance to prevent at least a portion of wavelengths of incident light from passing therethrough.
26 . The image sensor system according to claim 25 , wherein the first distance is less than or equal to about 0.4 um.
27 . The image sensor system according to claim 25 , wherein the first distance being less than or equal to the wavelengths of incident light.
28 . The image sensor system according to claim 25 , wherein the material blocks are arranged in the light transmission area separated by a second distance.
29 . The image sensor system according to claim 25 , wherein the material blocks comprise a metal material.
30 . The image sensor system according to claim 25 , wherein the material blocks are of a thickness and material so as to allow less than 1% of incident light to pass therethrough.
31 . A method of forming an image sensor comprising the acts of:
forming an array contacting a plurality of pixel cells, each pixel cell having a photosensor; and
forming a plurality of metal material blocks associated with and formed above the photosensor, the material blocks being arranged to define a light blocking area, the material blocks being arranged in the light blocking area to be separated by a first distance to prevent at least a portion of wavelengths of incident light from passing therethrough, and to define a light transmission area over the photosensor, the material blocks being arranged in the light transmission area to be separated by a second distance to allow light to pass through to the photosensor.
32 . The method according to claim 31 , wherein the first distance is less than or equal to about 0.4 um.
33 . The method according to claim 31 , wherein the first distance is less than or equal to the wavelengths of incident light.
34 . The method according to claim 31 , wherein the material blocks are of a thickness and material so as to allow less than 1% of incident light to pass therethrough and can be conductive or insulative material.
35 . A method of forming an image sensor comprising the acts of:
forming an array of pixel cells, each pixel cell having a photosensor;
forming a light shield comprising an opaque material above the photosensors; and
patterning the light shield to form a plurality of opaque material blocks per pixel cell associated with and formed above the photosensor, the plurality of material blocks being arranged to define a light blocking area, the material blocks being separated in the light blocking area by a first distance, the first distance being less than or equal to the wavelengths of incident light.
36 . The method according to claim 35 , further comprising the act of forming a conductive interconnect layer above the photosensor.
37 . The method according to claim 35 , further comprising of the material blocks being arranged to define a light transmission area, the material blocks being separated in the light transmission area by a second distance to allow light to pass through to the photosensor.
38 . The method according to claim 35 , wherein the first distance is less than or equal to about 0.4 um.
39 . The method according to claim 35 , wherein the step of forming the light shield comprises depositing a metal material.
40 . The method according to claim 35 , wherein the step of forming the light shield comprises depositing a material selected from the group consisting of tungsten, tungsten silicide, titanium, titanium nitride, cobalt, chromium, polysilicon-tungsten silicide, aluminum, titanium silicide, molybdenum, tantalum, and combinations thereof.
41 . The method according to claim 35 , wherein the step of patterning the light shield forms material blocks about 100 Å to about 3,000 Å thick.
42 . The method according to claim 35 , wherein the material blocks are of a thickness and material so as to allow less than 1% of incident light to pass therethrough and can be conductive or insulative material.