Method for manufacturing non-volatile semiconductor memory device, and non-volatile semiconductor memory device
View Patent ↗An isolation oxide film whose upper surface is higher than a surface of a substrate is formed in the substrate. A silicon oxide film is formed on the substrate between the isolation oxide films. A self-aligned polysilicon film is formed on the silicon oxide film between the isolation oxide films. After forming a resist pattern covering the peripheral circuitry, the isolation oxide films in the memory cell are etched by a predetermined thickness. An ONO film is formed on the entire surface of the substrate, a second resist pattern covering the memory cell is formed. Then, the ONO film, the polysilicon film 8 and the silicon oxide film 7 are removed from the peripheral circuitry.
1. A method for manufacturing a non-volatile semiconductor memory device having a memory cell and a peripheral circuitry, comprising:
forming element isolation structures for isolating active regions in a substrate, wherein an upper surface of the element isolation structure is higher than a surface of the substrate;
forming a silicon oxide film on the substrate;
forming a polysilicon film on the silicon oxide film;
self-aligning the polysilicon film to the element isolation structures by planarizing the polysilicon film by a CMP method using the element isolation structures as a stopper film;
forming a first resist pattern covering the peripheral circuitry adjacent to the memory cell;
etching the element isolation structures in the memory cell by a predetermined thickness using the first resist pattern as a mask so that the element isolation structures in the memory cell are lower than the element isolation structures in the peripheral circuitry;
forming a multilayer insulation film on an entire surface of the substrate;
forming a second resist pattern covering the memory cell;
removing the multilayer insulation film from the peripheral circuitry using the second resist pattern as a mask;
forming a gate insulation film on the substrate of the peripheral circuitry;
forming a conductive film on the entire surface of the substrate;
patterning the conductive film on the peripheral circuitry and the memory cell to form a patterned conductive film; and
patterning the multilayer insulation film and the polysilicon film on the memory cell using the patterned conductive film as a mask.
2. A method for manufacturing a non-volatile semiconductor memory device having a memory cell and peripheral circuitry, comprising:
forming element isolation structures for isolating active regions in a substrate, wherein an upper surface of the element isolation structure is higher than a surface of the substrate;
forming a silicon oxide film to be a tunnel oxide film on the substrate;
forming a polysilicon film to be a floating gate electrode on the silicon oxide film;
self-aligning the polysilicon film to the element isolation structures by planarizing the polysilicon film by a CMP method using the element isolation structures as a stopper film;
forming a first resist pattern covering the peripheral circuitry adjacent to the memory cell;
etching the element isolation structures in the memory cell by a predetermined thickness using the first resist pattern as a mask, to expose upper portions of sides of the polysilicon film in the memory cell so that the element isolation structures in the memory cell are lower than the element isolation structures in the peripheral circuitry;
forming a multilayer insulation film on an entire surface of the substrate, after removing the first resist pattern;
forming a second resist pattern covering the memory cell;
removing the multilayer insulation film from the peripheral circuitry using the second resist pattern as a mask.
3. The method for manufacturing a non-volatile semiconductor memory device according to claim 1 , wherein the active regions of the memory cell include:
a plurality of rectangular first active regions arrayed in lateral direction; and
second active regions connecting ends of the first active regions to each other, the second active regions surrounding the memory cell, and
wherein the first resist pattern is formed so that the ends of the first resist pattern are situated in the second active region.
4. The method for manufacturing a non-volatile semiconductor memory device according to claim 2 , wherein the active regions of the memory cell include:
a plurality of rectangular first active regions arrayed in lateral direction; and
second active regions connecting ends of the first active regions to each other, the second active regions surrounding the memory cell, and
wherein the first resist pattern is formed so that the ends of the first resist pattern are situated in the second active region.
5. The method for manufacturing a non-volatile memory semiconductor device according to claim 1 , wherein, in removing the multilayer insulation film, the polysilicon film, and the silicon oxide film from the peripheral circuitry, the upper surface of the element isolation structure in the peripheral circuitry becomes a height equivalent to a height of the surface of the substrate, or becomes higher than the height of the surface of the substrate.
6. The method for manufacturing a non-volatile memory semiconductor device according to claim 2 , wherein, in removing the multilayer insulation film, the polysilicon film, and the silicon oxide film from the peripheral circuitry, the upper surface of the element isolation structure in the peripheral circuitry becomes a height equivalent to a height of the surface of the substrate, or becomes higher than the height of the surface of the substrate.
7. A method for manufacturing a non-volatile semiconductor memory device having a memory cell and a peripheral circuitry, comprising:
forming element isolation structures for isolating active regions in a substrate, wherein an upper surface of the element isolation structure is higher than a surface of the substrate;
forming a silicon oxide film on the substrate;
forming a polysilicon film on the silicon oxide film;
self-aligning the polysilicon film to the element isolation structures by planarizing the polysilicon film by a CMP method using the element isolation structures as a stopper film;
forming a first resist pattern covering the peripheral circuitry adjacent to the memory cell;
etching the element isolation structures in the memory cell by a predetermined thickness using the first resist pattern as a mask so that the element isolation structures in the memory cell are lower than the element isolation structures in the peripheral circuitry;
forming a multilayer insulation film on an entire surface of the substrate;
forming a conductive film on the entire surface of the substrate;
patterning the conductive film on the peripheral circuitry and the memory cell to form a patterned conductive film; and
patterning the multilayer insulation film and the polysilicon film on the memory cell using the patterned conductive film as a mask.
8. A method for manufacturing a non-volatile semiconductor memory device having a memory cell and peripheral circuitry, comprising:
forming element isolation structures for isolating active regions in a substrate, wherein an upper surface of the element isolation structure is higher than a surface of the substrate;
forming a silicon oxide film to be a tunnel oxide film on the substrate;
forming a polysilicon film to be a floating gate electrode on the silicon oxide film;
self-aligning the polysilicon film to the element isolation structures by planarizing the polysilicon film by a CMP method using the element isolation structures as a stopper film;
forming a first resist pattern covering the peripheral circuitry adjacent to the memory cell;
etching the element isolation structures in the memory cell by a predetermined thickness using the first resist pattern as a mask, to expose upper portions of sides of the polysilicon film in the memory cell so that the element isolation structures in the memory cell are lower than the element isolation structures in the peripheral circuitry;
forming a multilayer insulation film on an entire surface of the substrate, after removing the first resist pattern;
forming a conductive film to be a gate electrode or a control gate electrode on the entire surface of the substrate;
patterning the conductive film on the peripheral circuitry and the memory cell, to form a gate electrode on the gate insulation film of the peripheral circuitry, and to form a control gate electrode on the multilayer insulation film of the memory cell; and
patterning the multilayer insulation film and the polysilicon film on the memory cell using the control gate electrode as a mask, to form a floating gate electrode.
9. The method for manufacturing a non-volatile semiconductor memory device according to claim 7 , further comprising:
forming a second resist pattern covering the memory cell; and
removing the multilayer insulation film, from the peripheral circuitry using the second resist pattern as a mask.
10. The method for manufacturing a non-volatile semiconductor memory device according to claim 8 , further comprising:
forming a second resist pattern covering the memory cell; and
removing the multilayer insulation film from the peripheral circuitry using the second resist pattern as a mask.