A semiconductor structure includes an optical component and a thermal control mechanism adjacent to the optical component and configured to control a temperature of the optical component. The thermal control mechanism includes a conductive structure, a first thermoelectric member and a second thermoelectric member opposite to the first thermoelectric member. The first thermoelectric member and the second thermoelectric member are electrically connected to the conductive structure. The first thermoelectric member and the second thermoelectric member have opposite conductive types. The semiconductor structure further includes a first dielectric layer surrounding the optical component and a portion of the thermal control mechanism, wherein the conductive structure is over the first dielectric layer, and the first thermoelectric member and the second thermoelectric member are surrounded by the first dielectric layer. The semiconductor structure further includes a first via extending through the first dielectric layer and electrically connected to the conductive structure.