Ion beam etching
Pattern-multiplication via a multiple step ion beam etching process utilizing multiple etching steps. The ion beam is stationary, unidirectional or non-rotational in relation to the surface being etched during the etching steps, but sequential etching steps can utilize an opposite etching direction. Masking elements are used to create additional masking elements, resulting in decreased spacing between adjacent structures and increased structure density.
1. A method comprising:
providing a substrate having a first masking element and a second masking element thereon, the first masking element separated from the second masking element along a surface of the substrate;
forming a first etched region by unidirectional ion beam etching the substrate from a first projection direction using the first masking element as a shading structure;
forming a second etched region and a third etched region by unidirectional ion beam etching from a second projection direction with an angle of projection about 180 degrees from the first projection direction using the second masking element as a shading structure;
forming a fourth etched region by unidirectional ion beam etching using the first masking element and the first etched region as shading structures;
forming a fifth etched region by unidirectional ion beam etching from the second projection direction with an angle of projection about 180 degrees from the projection direction used for forming the fourth etched region, using the second masking element and the second etched region as shading structures;
resulting in a third masking element and a fourth masking element between the first masking element and the second masking element.
2. The method of claim 1 , wherein forming a first etched region and forming a second etched region are at a first incidence angle, and forming a fourth etched region and forming a fifth etched region are at a second incidence angle different than the first incidence angle.
3. The method of claim 2 , wherein the second incidence angle is about twice the first incidence angle.
4. The method of claim 1 , wherein forming a fourth etched region is from the first projection direction, and forming a fifth etched region is from the second projection direction.
5. The method of claim 1 , wherein forming a fourth etched region is from the second projection direction, and forming a fifth etched region is from the first projection direction.
6. The method of claim 1 , wherein the density of the first masking element, the second masking element, the third masking element and the fourth masking element is 3 times the density of the first masking element and a second masking element.
7. A method comprising:
providing a substrate having a first masking element and a second masking element thereon, the first masking element separated from the second masking element along a surface of the substrate;
unidirectionally etching the substrate from a first projection direction at a first incidence angle;
unidirectionally etching the substrate from a second projection direction with an angle of projection about 180 degrees from the first projection direction at the first incidence angle;
unidirectionally etching the substrate at a second incidence angle to form a third masking element on the substrate between the first masking element and the second masking element; and then
unidirectionally etching the substrate with an angle of projection about 180 degrees from the projection direction of the previous etching at the second incidence angle to form a fourth masking element on the substrate between the first masking element and the second masking element.
8. The method of claim 7 , wherein a density of the first masking element, the second masking element, the third masking element and the fourth masking element is 3 times the density of the first masking element and a second masking element.
9. The method of claim 7 , wherein the second incidence angle is about twice the first incidence angle.
10. The method of claim 7 , wherein unidirectionally etching the substrate at a second incidence angle to form a third masking element is from the first projection direction, and unidirectionally etching the substrate at the second incidence angle to form a fourth masking element is from the second projection direction.
11. The method of claim 7 , wherein unidirectionally etching the substrate at a second incidence angle to form a third masking element is from the second projection direction, and unidirectionally etching the substrate at the second incidence angle to form a fourth masking element is from the first projection direction.