Self-Aligned Borderless Diffusion Contacts
Original Publication Date: 1988-Dec-01
Included in the Prior Art Database: 2005-Feb-15
A process sequence is disclosed which produces diffusion contacts which are self-aligned to the first level polysilicon features and do not require borders, resulting in a significant circuit density increase. A major feature inhibiting increased semiconductor circuit density is a requirement to surround contact windows with a border because contact windows are defined by a separate mask level. A process sequence is shown which produces diffusion contacts which are self-aligned to the first level polysilicon (poly 1). The process steps are as follows: 1) Fig. 1 shows a composite cap of silicon dioxide 10 (300-500 angstroms thick) and silicon nitride 11 (1,000 angstroms thick) on top of a base structure of oxide 12 and polysilicon 13 following a poly 1 (P1) etch, resist removal and sidewall oxidation 14.