Dual glass contact process

摘要

A method for forming contact openings in semiconductor devices. In borosilicate glass layers deposited over the gate and drain area of a device, followed by a borophosphosilicate glass layer. After masking with photoresist and defining openings, the borophosphosilicate glass is isotropically etched to undercut the resist layer. A plasma etch is utilized to anisotropically etch the borosilicate glass layer and expose the surface of the drain area. After the photoresist is stripped away, a reflow step is employed to reduce the sharp edges of the glass layer and result in a sloped contact opening profile. Good metal coverage is achieved while maintaining isolation of the gate.