| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent excess etching owing to an etching quantity difference at the time of forming contact holes differing in depths by forming a buffer layer with a substance with a large etching selection ratio, compared to a first insulating film and a second insulating film and preventing a conductive layer from being etched at the time of forming the first and second contact holes. SOLUTION: A first insulating layer 52 and a conductive layer 54 are formed on a semiconductor substrate 50. A buffer layer 56 is formed by a substance with a larger etching selection ratio against high temperature oxide and BPSG. The conductive layer 54 is patterned, the conductive layer 54 is insulated, and a second insulating layer 58 is formed. At the time of forming the first contact hole h1 and the second contact hole h2 , the buffer layer 56 prevents the lower conductive layer 54 from being etched. Thus, insufficiency in etching a margin owing to the difference of etching quantity at the time of simultaneously forming the contact holes different in depth can be solved.</p> |
