Non-volatile memory production, e.g. EEPROM

摘要

Non-volatile memory production comprises: (a) forming spaced parallel second conductivity lines (42) below the surface of a first conductivity type substrate (41); (b) forming and selectively removing an insulation layer (44) and an overlying first conductive layer on the structure surface to obtain spaced first conductive lines (45) at right angles to the bit lines (42); (c) forming a gate insulation layer (46) on the substrate and simultaneously forming a tunnelling insulation layer (47) on the surfaces of the first conductive lines; (d) forming a second conductive layer and selectively removing the second conductive layer, the tunnelling insulation layer (47) and the first conductive lines (45) to form second conductive lines (48) for floating gates and programming gates (49) between the bit lines (42); (e) forming a dielectric film (50) on the second conductive lines (48); (f) forming a third conductive layer and an overlying insulating layer (52) on the entire surface including the dielectric layer (50) and selectively removing the insulating layer (52), the third conductive layer, the dielectric layer (50) and the second conductive lines (48) to form word lines (51) and floating gates (53) between the first conductive lines (45) and at right angles to the bit lines (42); (g) forming insulating sidewall pieces (54) on both sides of the structured insulating layer (52), the word lines (51), the dielectric layer (52) and the floating gates (53); (h) selectively structuring the programming tunnelling insulation layer (47) using the sidewall pieces (54) as masks to produce contact openings; and (i) forming programming lines on the insulating layer (52) and between the bit lines (42), the programming lines (55) being electrically connected to the programming gates (49) via the contact openings. Also claimed is a similar process in which the bit lines are formed in the above step (a).