A sample holder includes a base comprising a support structure and a printed circuit board (PCB) in contact with the base. The PCB has a through hole. The PCB has a cavity in at least a part of the base below the through hole. The support structure that supports a surface of a chip and is electrically connected to the base. The support structure is disposed in the cavity. At least a part of the section supporting the chip in the support structure is not parallel to the back surface of the chip.