Semiconductor device structure with composite hard mask and method for preparing the same

A semiconductor device structure, comprising:

• a first dielectric layer disposed on a top surface of a semiconductor substrate, wherein the first dielectric layer is made of a material adapted to be removed during an etching process;
• a second dielectric layer disposed on and in contact with a top surface of the first dielectric layer, wherein the second dielectric layer is made of a material adapted to be removed during the etching process;
• a first semiconductor structure disposed over the second dielectric layer, wherein the first semiconductor structure has a first portion, a second portion separated from the first portion, and a third portion separated from the second portion by a first opening;
• and
• a second semiconductor structure disposed over the second dielectric layer, wherein the second semiconductor structure has a first portion, a second portion separated from the first portion by a second opening, and a third portion separated from the second portion, and
• wherein the first portion of the second semiconductor structure is in direct contact with the first portion of the first semiconductor structure, the second portion of the second semiconductor structure is in direct contact with the second portion of the first semiconductor structure, and the third portion of the second semiconductor structure is in direct contact with the third portion of the first semiconductor structure;
• wherein the first portion and the second portion of the second semiconductor structure are located between the first portion and the second portion of the first semiconductor structure;
• wherein the second portion and the third portion of the first semiconductor structure are located between the second portion and the third portion of the second semiconductor structure;
• wherein the first semiconductor structure and the second semiconductor structure are made of different materials and collectively form a composite hard mask for being utilized in the etching process for the first dielectric layer and the second dielectric layer.