Abstract A method of making a semiconductor memory device wherein a storage node having a plurality of pillars, capable of increasing the storage node surface area and thus the cell capacitance. The storage node is formed by depositing a storage node polysilicon film to have a thickness of 5,000 Å to 6,000 Å over a semiconductor substrate, forming a photoresist pattern over the polysilicon film in a direct electron beam writing manner, and etching the polysilicon film up to a depth of 1,000 Å from the upper surfaces of a gate and a bit line by using the photoresist pattern. The formed storage node has a plurality of uniformly spaced pillars. Alternatively, the storage node is formed by forming a smoothing insulating film over the semiconductor substrate depositing a storage node polysilicon film over the smoothing insulating film, primarily photo exposing the semiconductor substrate using a glass mask having phase shifters, secondarily photo exposing the semiconductor substrate under the condition of rotating 90° the semiconductor substrate, to form a check-board photoresist pattern, and patterning the polysilicon film using the photoresist pattern as a mask. The formed storage node has a plurality of pillars arranged independently or intersectionally.
A method of making a semiconductor memory device comprising the steps of: forming a transistor on a semiconductor substrate; forming a polysilicon film over exposed surfaces of the semiconductor substrate; preparing a glass mask having a plurality of phase shifters; coating a photoresist over the polysilicon film; primarily photo exposing the semiconductor substrate under the condition of fixing the glass mask at a position spaced a distance from the semiconductor substrate; secondarily photo exposing the semiconductor substrate under the condition of rotating 90° the semiconductor substrate at the same position as in the step of primarily photo exposing the semiconductor substrate; developing the photoresist to form a photoresist pattern; etching the polysilicon film using the photoresist pattern as a mask, to form a storage node having a plurality of pillars; p1 removing the photoresist;
Claim 2
Independent Claim
134 words
A method of making a semiconductor memory device comprising the steps of: forming a transistor on a semiconductor substrate; forming a polysilicon film over exposed surfaces of the semiconductor substrate; preparing a glass mask having a plurality of phase shifters; coating a photoresist over the polysilicon film; primarily photo exposing the semiconductor substrate under the condition of fixing the glass mask at a position spaced a distance from the semiconductor substrate; secondarily photo exposing the semiconductor substrate under the condition of rotating 90° the semiconductor substrate at the same position as in the step of primarily photo exposing the semiconductor substrate; developing the photoresist to form a photoresist pattern; etching the polysilicon film using the photoresist pattern as a mask, to form a storage node having a plurality of pillars; p1 removing the photoresist;
Claim 3
Dependent Claim
31 words
A method in accordance with claim 1, wherein the phase shifters have a rectangular shape and are arranged on the glass mask in one direction and uniformly spaced from one another.
Claim 4
Dependent Claim
46 words
A method in accordance with claim 1, wherein the step of secondarily photo exposing the semiconductor substrate is carried out under the condition of rotating the glass mask ninety degrees (90° ), in place of the condition of rotating the semiconductor substrate ninety degrees (90° ).
Claim 5
Dependent Claim
20 words
A method in accordance with claim 1, wherein the photoresist comprises one of a positive photoresist or a negative photoresist.
Claim 6
Dependent Claim
31 words
A method in accordance with claim 1, wherein the photoresist comprises a positive photoresist and further the pillars of the storage node are arranged independently and uniformly spaced from one another.
Claim 7
Dependent Claim
25 words
A method in accordance with claim 1, wherein the photoresist comprises a negative photoresist and further the pillars of the storage node are intersectionally arranged.
Claim 8
Dependent Claim
31 words
A method in accordance with claim 4, wherein the photoresist comprises a positive photoresist and further the pillars of the storage node are arranged independently and uniformly spaced from one another.
Claim 9
Dependent Claim
25 words
A method in accordance with claim 4, wherein the photoresist comprises a negative photoresist and further the pillars of the storage node are intersectionally arranged.