FORMATION OF A HIGH ASPECT RATIO CONTACT HOLE

摘要

A small contact hole having a large aspect ratio is formed by employing a stop layer with a trench formed therein. A relatively large contact hole is formed above the trench, and the small contact hole is formed below the trench, using properties of the trench and the stop layer to limit the size of the small contact hole.

主权项

1. A method, comprising:
providing a semiconductor film stack having a first plurality of layers including a contact layer; disposing a stop layer over the first plurality of layers; introducing a trench into the stop layer, thereby forming a shaped stop layer, the trench having an upper width and a lower width, the lower width being less than the upper width; placing a second plurality of layers into the trench and above the shaped stop layer; forming a relatively large contact hole through the second plurality of layers; and forming a relatively small contact hole extending downward from a lower extent of the trench to the contact layer, the small contact hole having a cross-section substantially the same as the lower width of the trench.