Analytical biochip and forming method thereof

A method of forming an analytical biochip, comprising:

• forming a lower cladding layer over a substrate;
• forming a waveguide over the lower cladding layer, wherein the waveguide comprises a grating coupler and a guiding portion coupled to the grating coupler, wherein the grating coupler is configured to receive excitation energy from an excitation source, and the guiding portion is configured to guide the excitation energy;
• forming an upper cladding layer over the waveguide;
• patterning the upper cladding layer to form upper protrusion structures at an upper surface of the upper cladding layer;
• forming an emission light collection element covering the upper protrusion structures, wherein portions of the emission light collection element extends into the upper cladding layer, and the emission light collection element is made of metal;
• and
• forming a plurality of nanowells penetrating the emission light collection element and in the upper cladding layer, wherein the plurality of nanowells are configured to receive samples tagged with fluorescent tags, and at least a portion of the guiding portion of the waveguide is directly below the plurality of nanowells;
• wherein each of the plurality of nanowells is spaced apart from the grating coupler, and the excitation energy is guided by the guiding portion of the waveguide toward the plurality of nanowells to thereby enable the fluorescent tags of the samples in the plurality of nanowells to absorb the excitation energy and emit light.