Abstract: Present disclosure provides a method for multi-level etch. The method includes providing a substrate, forming a first reference feature over a control region of the substrate, forming an etchable layer over the first reference feature and a target region over the substrate, patterning a masking layer over the etchable layer, the masking layer having a first opening projecting over the control region and a second opening projecting over the target region, and removing a portion of the etchable layer through the first opening and the second opening until the first reference feature is reached. A semiconductor sensing device manufactured by the multi-level etch is also disclosed.

Abstract: A biosensors and a method of forming a probe on a solid surface of a biosensor are disclosed and the method includes the following steps. A unit (a nucleotide or an amino acid) capped with a protecting group is covalently bonded on the solid surface of one of a plurality of sensor cells of the biosensor. At least one cycle of the following steps is performed until a desired number of units is formed: irradiating the one of the plurality of sensor cells, so as to remove the protecting group of the unit; and binding a unit capped with the protecting group to the de-protected unit. The one of the plurality of sensor cells is irradiated to remove the protecting group.