Semiconductor device manufacturing: process – Making device or circuit responsive to nonelectrical signal – Physical stress responsive
Reexamination Certificate
2008-07-29
2008-07-29
Toledo, Fernando L. (Department: 2823)
Semiconductor device manufacturing: process
Making device or circuit responsive to nonelectrical signal
Physical stress responsive
C438S051000, C438S052000, C438S053000, C257S414000, C257S415000, C257S417000
Reexamination Certificate
active
11192198
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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Freescale Semiconductor Inc.
Ingrassia Fisher & Lorenz P.C.
Lee Jae
Toledo Fernando L.
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