Abstract:
Method for manufacturing non volatile memory cells integrated on a semiconductor substrate (100), each one comprising a floating gate electrode (110), the method comprising the steps of: - depositing at least one protective layer (30) on the semiconductor substrate (100), - forming a first plurality of openings (40) in the protective layer (30), - etching the semiconductor substrate (100) through the first plurality of openings (40) so as to form a plurality of trenches (60), - filling in the plurality of trenches (60) and the first plurality of openings (40) by means of an insulation layer (70), - etching surface portions of the protective layer (30) to form: - surface portions (71) of the insulation layer (70) projecting from the semiconductor substrate (100) divided from each other by a second plurality of openings (72), and - lower portions (31) of the protection layer (30) confined below the second plurality of openings (72),
- etching the insulation layer (70) to reduce the cross dimensions of the surface portions (71) of the insulation layer (70), - removing the lower portions (31) of said protection layer (30) until the semiconductor substrate (100) is exposed.
Abstract:
A method for manufacturing circuit structures integrated in a semiconductor substrate (1) that includes regions (2), in particular isolation regions, the method comprising the steps of:
depositing a conductive layer (3) to be patterned onto said semiconductor substrate (1); forming a first mask (4b) of a first material on said conductive layer (3); forming a second mask (5b) made of a second material that is different from the first and provided with first openings (10,12) of a first size (A) having spacers (8,8a) formed on their sidewalls to uncover portions of said first mask (4b) having a second width (B) which is smaller than the first; partly etching away said conductive layer (3) through said first and second masks (4b,5b) such to leave grooves (13) of said second width (B); removing said second mask (5a) and said spacers (8); and etching said grooves (13) through said first mask (4b) to uncover said regions (2) provided in said substrate (1) and form conductive lines (3a).