A gate structure is formed over a substrate. The gate structure includes a gate electrode and a hard mask located over the gate electrode. The hard mask comprises a first dielectric material. A first interlayer dielectric (ILD) is formed over the gate structure. The first ILD comprises a second dielectric material different from the first dielectric material. A first via is formed in the first ILD. Sidewalls of the first via are surrounded by spacers that comprise the first dielectric material. A second ILD is formed over the first ILD. A via hole is formed in the second ILD. The via hole exposes the first via. A protective layer is formed in the via hole. A bottom segment of the protective layer is removed. Thereafter, an etching process is performed. A remaining segment of the protective layer prevents an etching of the spacers during the etching process.