Patent ID: 7365021
Filing Date: 2008-04-29
Classification: H01L

Abstract:
1. A method of fabricating a semiconductor device comprising the steps of: sequentially forming a metal interconnection, a protecting layer, a molding layer and an etching stop layer on a semiconductor substrate; forming a contact hole directly on the protecting layer so as to expose a portion of said protecting layer, wherein said hole is substantially aligned with the metal interconnection and penetrates both the molding layer and the etching stop layer stacked on said protecting layer; forming a sacrificial layer on the etching stop layer so as substantially to fill the contact hole; forming a photoresist layer on said sacrificial layer, said photoresist layer having an opening so as to leave exposed a portion of the sacrificial layer, said opening having substantially the same center line as the contact hole; performing a first etching process on the sacrificial layer, the etching stop layer, and the molding layer using the photoresist layer as an etching mask, thereby forming a trench on the semiconductor substrate, the trench being formed in the molding layer and penetrating the sacrificial layer and the etching stop layer, while leaving a portion of the sacrificial layer inside the contact hole; and performing a second etching process by an isotropic wet etching technique using the etching stop layer as a buffered layer, thereby concurrently or sequentially etching and removing the photoresist pattern, the sacrificial layer and the portion of the sacrificial layer remaining inside the contact hole from the semiconductor substrate using a buffered etching composition that may also contact the protecting layer, molding layer and etching stop layer during the second etching process, further wherein said buffered etching composition comprises an amine-based organic component and a fluoride-based component, and also wherein during etching the buffered etching composition has an etching ratio less than 1 based on the rates at which the buffered etching composition etches the protective layer, molding layer and etching stop layer relative to the rates at which it etches the photoresist layer and the sacrificial layer.