Conversion structure, image sensor assembly and method for fabricating conversion structure

An image sensor assembly, comprising:

• a conversion structure, comprising:
• a first substrate, having a first surface and a second surface opposite to the first surface, wherein the second surface of the substrate has a plurality of trenches penetrating the substrate;
• a plurality of electromagnetic wave conversion elements, respectively disposed in each of the trenches, wherein each of the electromagnetic wave conversion elements is used to absorb a first electromagnetic wave having a first electromagnetic wave wavelength and to emit a second electromagnetic wave having a second electromagnetic wave wavelength, and the first electromagnetic wave wavelength is shorter than the second electromagnetic wave wavelength;
• a reflective film, covering on the first surface of the substrate, wherein the first electromagnetic wave penetrates the reflective film, and the reflective film is used to reflect the second electromagnetic wave;
• and
• a plurality of reflective layers, respectively disposed between a sidewall of each of the trenches and each of the electromagnetic wave conversion elements, wherein the reflective layers are used to reflect the second electromagnetic waves;
• and
• a light sensor assembly, disposed opposite to the second surface of the first substrate and comprising a plurality of sensing regions, the light sensor assembly comprising:
• a second substrate;
• and
• a plurality of light sensor devices, respectively disposed within each of the sensing regions on the second substrate.

A method of fabrication a conversion structure, comprising:

• providing a substrate having a first surface and a second surface opposite to the first surface;
• forming a plurality of trenches penetrating the substrate on the second surface;
• depositing a reflective film on the first surface of the substrate;
• forming a reflective layer on a sidewall of each of the trenches;
• and
• filling an electromagnetic wave conversion element into each of the trenches, wherein each of the electromagnetic wave conversion elements is used to absorb a first electromagnetic wave having a first electromagnetic wave wavelength and to emit a second electromagnetic wave having a second electromagnetic wave wavelength, and the first electromagnetic wave wavelength is shorter than the second electromagnetic wave wavelength.