The present disclosure discloses a semiconductor device structure with an air gap for reducing capacitive coupling and a method for forming the semiconductor device structure. The semiconductor device structure includes a first conductive pad over a first semiconductor substrate, and a first conductive structure over the first conductive pad. The semiconductor device structure also includes a second conductive structure over the first conductive structure, and a second conductive pad over the second conductive structure. The second conductive pad is electrically connected to the first conductive pad through the first and the second conductive structures. The semiconductor device structure further includes a second semiconductor substrate over the second conductive pad, a first passivation layer between the first and the second semiconductor substrates and covering the first conductive structure, and a second passivation layer between the first passivation layer and the second semiconductor substrate. The first and the second passivation layers surround the second conductive structure, and a first air gap is enclosed by the first and the second passivation layers.