Wide and narrow trench formation in high aspect ratio MEMS
First Claim
1. A method of forming a high-aspect ratio microelectromechanical (MEM) device on a substrate including a substrate layer, an active layer, and a first sacrificial layer disposed at least partially therebetween, the method comprising the steps of:
- forming a first trench, a second trench, and a third trench in the active layer, each trench having an opening and sidewalls defining substantially equal first trench widths;
forming a second sacrificial layer over a surface of the active layer and the sidewalls of each of the trenches;
forming a third sacrificial layer over the second sacrificial layer and sealing the openings of each of the trenches with the third sacrificial layer;
forming an etch hole in the second sacrificial layer and the third sacrificial layer between the first trench and the second trench to expose a portion of the active layer;
removing material from the active layer between the first trench and the second trench to form a cavity having sidewalls and an opening;
forming a fourth sacrificial layer over the third sacrificial layer and the sidewalls of the cavity and sealing the cavity and its opening with the fourth sacrificial layer; and
removing the second sacrificial layer, the third sacrificial layer, and the fourth sacrificial layer to expose the third trench and form a fourth trench in the active layer from the first and the second trench, the fourth trench having sidewalls defining a second trench width that is greater than the first trench width.
20 Assignments
0 Petitions
Accused Products
Abstract
Methods have been provided for forming both wide and narrow trenches on a high-aspect ratio microelectromechanical (MEM) device on a substrate including a substrate layer (126), an active layer (128), and a first sacrificial layer (130) disposed at least partially therebetween. The method includes the steps of forming a first trench (154), a second trench (156), and a third trench (152) in the active layer (128), each trench (154, 156, 152) having an opening and sidewalls defining substantially equal first trench widths, depositing oxide and sacrificial layers thereover and removing the oxide and sacrificial layers to expose the third trench (152) and form a fourth trench (190) in the active layer (128) from the first and the second trench (154, 156), the fourth trench (190) having sidewalls defining a second trench width that is greater than the first trench width.
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Citations
19 Claims
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1. A method of forming a high-aspect ratio microelectromechanical (MEM) device on a substrate including a substrate layer, an active layer, and a first sacrificial layer disposed at least partially therebetween, the method comprising the steps of:
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forming a first trench, a second trench, and a third trench in the active layer, each trench having an opening and sidewalls defining substantially equal first trench widths; forming a second sacrificial layer over a surface of the active layer and the sidewalls of each of the trenches; forming a third sacrificial layer over the second sacrificial layer and sealing the openings of each of the trenches with the third sacrificial layer; forming an etch hole in the second sacrificial layer and the third sacrificial layer between the first trench and the second trench to expose a portion of the active layer; removing material from the active layer between the first trench and the second trench to form a cavity having sidewalls and an opening; forming a fourth sacrificial layer over the third sacrificial layer and the sidewalls of the cavity and sealing the cavity and its opening with the fourth sacrificial layer; and removing the second sacrificial layer, the third sacrificial layer, and the fourth sacrificial layer to expose the third trench and form a fourth trench in the active layer from the first and the second trench, the fourth trench having sidewalls defining a second trench width that is greater than the first trench width. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of forming a wide trench and a narrow trench on a substrate including an active layer disposed over a first sacrificial layer, the active layer having a surface, the method comprising the steps of:
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etching a first trench and a second trench through the active layer to expose a surface of the first sacrificial layer, each trench having an opening, sidewalls defining a first trench width, and substantially equal and uniform first trench widths; oxidizing the surface of the active layer and the sidewalls of the first trench and second trench; depositing a sacrificial material over the oxidized surfaces to form a second sacrificial layer; sealing the openings of the trenches with at least a portion of the second sacrificial layer; etching a hole through a portion of the second sacrificial layer and the oxidized surface to expose a portion of the active layer; removing material from the active layer between the first trench and the second trench to form a cavity having sidewalls; depositing another sacrificial material over the second sacrificial layer and the sidewalls of the cavity to form a third sacrificial layer; sealing the cavity with at least a portion of the third sacrificial layer; and removing the second sacrificial layer, the third sacrificial layer, and material from the oxidized surface of the active layer to form a third trench in the active layer from the first and the second trenches, the third trench having sidewalls defining a second trench width that is greater than the first trench width. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method of forming a wide trench and a narrow trench on a substrate including an active layer disposed over a first sacrificial layer, the active layer having a surface, the method comprising the steps of:
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forming a first trench, a second trench, and a third trench in the active layer, each trench having an opening and sidewalls defining substantially equal first trench widths; oxidizing the surface of the active layer and the sidewalls of the first trench, the second trench, and the third trench to form a second sacrificial layer; depositing a sacrificial material over the second sacrificial layer to form a third sacrificial layer; sealing the openings of the trenches with at least a portion of the third sacrificial layer; etching a hole through a portion of the second sacrificial layer and the third sacrificial layer to expose a portion of the active layer; removing material from the active layer between the first trench and the second trench to form a cavity having sidewalls; depositing another sacrificial material over the third sacrificial layer and the sidewalls of the cavity to form a fourth sacrificial layer; sealing the cavity with at least a portion of the fourth sacrificial layer; and removing the second sacrificial layer, the third sacrificial layer, and fourth sacrificial layer to expose the third trench and form a fourth trench in the active layer from the first and the second trenches, the fourth trench having sidewalls defining a second trench width that is greater than the first trench width.
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Specification