Method to optimize substrate thickness for image sensor device

An image sensor device, comprising:

• a substrate having a front side, a backside, and a thickness;
• a doped isolation feature formed in the substrate, the doped isolation feature having a first width and a depth, the depth being substantially equal to the thickness of the substrate;
• and
• a light sensing feature formed adjacent to the doped isolation feature in the substrate, the light sensing feature having a second width;
• wherein the first and second widths are determined by a pixel size and an optimization ratio, wherein the pixel size is a sum of the first and second widths and the optimization ratio specifies a correlation between the first and second widths.

A semiconductor device, comprising:

• a substrate having a front side and a back side and a thickness measured in a first direction;
• a radiation-detection device formed in the substrate, the radiation-detection device being operable to detect a radiation wave that enters the substrate through the back side, the radiation-detection device having a first dimension measured in a second direction substantially perpendicular to the first direction;
• and
• an isolation device formed in the substrate, the isolation device having a second dimension measured in the second direction and a third dimension measured in the first direction;
• wherein:
• the second dimension is correlated to the first dimension in a manner such that a predetermined ratio exists between the first and second dimensions;
• and
• the third dimension is approximately equal to the thickness of the substrate.

A semiconductor device, comprising:

• a substrate having a front side and a back side;
• a doped radiation-sensing structure formed in the substrate, the radiation-sensing structure extending from the front side toward the back side, the radiation-sensing structure being operable to sense radiation projected toward the substrate from the back side;
• and
• an isolation structure formed in the substrate and adjacent to the radiation-sensing structure, the isolation structure including first and second isolation elements that are doped differently from the radiation-sensing element and that extend toward each other from opposite sides of the substrate;
• wherein the radiation-sensing structure and the isolation structure have respective first and second lateral dimensions that are measured in a horizontal direction and mathematically correlated with each other in a manner such that a predefined ratio exists between them.