Two-level lithographic mask for producing tapered depth
First Claim
1. A method of forming a sloping surface, comprising the steps ofdepositing on a principle surface of a substrate material a first layer of a first material of a first composition;
- depositing on an outer surface of said first layer a second layer of a second material of a second composition;
patterning said second layer so as to expose a portion of said first layer; and
applying an etching medium to said principle surface deposited with said first layer and with said patterned second layer for etching said substrate material and said first layer, said etching medium having a first etching rate for said substrate material and a second etching rate for said first material greater than said first etching rate, said etching medium etching said second material, if at all, at an etching rate less than said first etching rate.
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Accused Products
Abstract
A method of producing a sloped surface in a semiconductor material. In the area where the slope is desired a dynamic mask is applied to the surface of the semiconductor. A standard mask is applied over the dynamic mask and patterned so that its edge laterally defines the bottom of the desired slope. The sample is then immersed in an etchant that etches the dynamic mask faster than the semiconductor material. The standard mask is not appreciably etched. The dynamic mask is progressively etched laterally, thereby dynamically exposing more of the semiconductor material to etchant and producing a sloped surface therein.
50 Citations
15 Claims
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1. A method of forming a sloping surface, comprising the steps of
depositing on a principle surface of a substrate material a first layer of a first material of a first composition; -
depositing on an outer surface of said first layer a second layer of a second material of a second composition; patterning said second layer so as to expose a portion of said first layer; and applying an etching medium to said principle surface deposited with said first layer and with said patterned second layer for etching said substrate material and said first layer, said etching medium having a first etching rate for said substrate material and a second etching rate for said first material greater than said first etching rate, said etching medium etching said second material, if at all, at an etching rate less than said first etching rate. - View Dependent Claims (2, 3, 4, 5)
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6. A method of forming a sloping surface in a semiconductor material, comprising the steps of
depositing on a principle surface of the semiconductor material a first layer of a first material of a first composition; -
depositing on an outer surface of said first layer a second layer of a second material of a second composition; patterning said second layer so as to expose a portion of said first layer; and applying an etching medium to said principle surface deposited with said first layer and with said patterned second layer for etching said semiconductor material and said first layer, said etching medium having a first etching rate for said semiconductor material and a second etching rate for said first material greater than said first etching rate, said etching medium etching said second material, if at all, at an etching rate less than said first etching rate. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification