Flash memory device and method of manufacturing the same
View Patent ↗Disclosed herein are flash memory devices and methods of making the same. According to one embodiment, a flash memory device includes first trenches formed in a semiconductor substrate and arranged in parallel, second trenches discontinuously formed in the semiconductor substrate and arranged between the first trenches, first isolation structures respectively formed within the first trenches, second isolation structures respectively formed within the second trenches, and active regions defined by the first isolation structures and the second isolation structures.
1. A method of manufacturing a flash memory device, the method comprising:
forming first auxiliary patterns arranged in a matrix form over a semiconductor substrate, wherein the matrix is defined by the first auxiliary patterns that are spaced apart from each other at a first interval and are arranged in a same column, and the first auxiliary patterns are spaced apart from each other at a second interval and are arranged in a same row;
forming a second auxiliary pattern on sidewalls of each of the first auxiliary patterns;
removing the first auxiliary patterns;
etching the semiconductor substrate through an etch process using the second auxiliary patterns as an etch mask to form the first and second trenches in the semiconductor substrate, wherein the first trenches are arranged in parallel, and the second trenches are discontinuously arranged between the first trenches;
removing the second auxiliary patterns; and
forming first isolation structures within the respective first trenches and second isolation structures within the respective second trenches, thereby defining active regions by the first isolation structures and the second isolation structures.
2. The method of claim 1 , wherein the first interval is at least 1.5 times a width of the first auxiliary pattern and no more than 2 times a width of the second auxiliary pattern.
3. The method of claim 2 , wherein the second interval is wider than the first interval.
4. The method of claim 1 , wherein the second trenches are arranged between the first trenches one by one.
5. The method of claim 1 , wherein the second auxiliary patterns are coupled together between the first auxiliary patterns arranged in the same column.
6. A method of manufacturing a flash memory device, the method comprising:
forming first auxiliary patterns arranged in a matrix form over a semiconductor substrate, wherein the matrix is defined by the first auxiliary patterns that are spaced apart from each other at a first interval and are arranged in a same column, and the first auxiliary patterns are spaced apart from each other at a second interval and are arranged in a same row;
forming a second auxiliary pattern on sidewalls of each of the first auxiliary patterns, wherein the second auxiliary patterns are coupled together between the first auxiliary patterns arranged in the same column;
removing the first auxiliary patterns;
forming third auxiliary patterns over one or more of portions where the second auxiliary patterns are coupled together;
etching the semiconductor substrate through an etch process using the second auxiliary patterns and the third auxiliary patterns as an etch mask to form first and second trenches in the semiconductor substrate, wherein the first trenches are arranged in parallel, and the second trenches are discontinuously arranged between the first trenches;
removing the second and third auxiliary patterns; and
forming first isolation structures within the respective first trenches and second isolation structures within the respective second trenches, thereby defining active regions by the first isolation structures and the second isolation structures.
7. The method of claim 6 , wherein the first interval is at least 1.5 times a width of the first auxiliary pattern and no more than 2 times a width of the second auxiliary pattern.
8. The method of claim 7 , wherein the second interval is wider than the first interval.
9. The method of claim 6 , wherein two or more second trenches are arranged between the first trenches.
10. The method of claim 6 , further comprising, after the step of forming the first and second isolation structures, injecting an impurity ion into the active region between the second trench to form a source region or a well pickup region.
11. A method of manufacturing a flash memory device, the method comprising:
forming a number of first auxiliary patterns arranged in a matrix form over a semiconductor substrate;
forming second auxiliary patterns separated from each other in a space between the first auxiliary patterns arranged in a same column, wherein each of the second auxiliary patterns is formed on sidewalls of each of the first auxiliary patterns such that the second auxiliary patterns are separated from each other in a space between the first auxiliary patterns arranged in a same row;
removing the first auxiliary patterns;
forming a third auxiliary pattern blocking a space between the second auxiliary patterns arranged in a same column;
etching the semiconductor substrate through an etch process using the second and third auxiliary patterns as an etch mask to form trenches arranged in a matrix; and
forming isolation structures within the respective trenches.
12. The method of claim 11 , wherein the third auxiliary pattern is formed in a line fashion to intersect the second auxiliary patterns arranged in the same column.
13. The method of claim 11 , further comprising, after the step of forming the isolation structures, injecting impurity ion into a space between the isolation structures to form a source region or a well pickup region.