Method and apparatus for detecting endpoint during plasma etching of thin films
First Claim
1. A method for controlling a plasma etch process in a plasma processing chamber, comprising:
- introducing a substrate having thereon a layer stack into said plasma processing chamber, said layer stack including a first layer disposed above an end-point generating layer;
etching through said first layer and at least partially through said end-point generating layer while monitoring an absorption rate of a light beam traversing an interior portion of said plasma processing chamber, wherein said endpoint generating layer is selected from a material that produces a detectable change in said absorption rate when etched, said end-point generating layer being characterized by at least one of a first characteristic and a second characteristic, said first characteristic being an insufficient thickness to function as an etch stop layer for said etching, said second characteristic being an insufficient selectivity to etchants employed to etch through said first layer to function as said etch stop layer; and
generating an end-point signal upon detecting said detectable change.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for controlling a plasma etch process while etching a layer stack having a first layer disposed above an end-point generating layer is disclosed. The method includes etching through the first layer and at least partially through the end-point generating layer while monitoring an absorption rate of a light beam traversing an interior portion of the plasma processing chamber, wherein the end-point generating layer is selected from a material that produces a detectable change in the absorption rate when etched. The end-point generating layer is characterized by at least one of a first characteristic and a second characteristic. The first characteristic is an insufficient thickness to function as an etch stop layer, and the second characteristic is an insufficient selectivity to etchants employed to etch through the first layer to function as the etch stop layer. The method additionally includes generating an end-point signal upon detecting the detectable change.
-
Citations
90 Claims
-
1. A method for controlling a plasma etch process in a plasma processing chamber, comprising:
-
introducing a substrate having thereon a layer stack into said plasma processing chamber, said layer stack including a first layer disposed above an end-point generating layer;
etching through said first layer and at least partially through said end-point generating layer while monitoring an absorption rate of a light beam traversing an interior portion of said plasma processing chamber, wherein said endpoint generating layer is selected from a material that produces a detectable change in said absorption rate when etched, said end-point generating layer being characterized by at least one of a first characteristic and a second characteristic, said first characteristic being an insufficient thickness to function as an etch stop layer for said etching, said second characteristic being an insufficient selectivity to etchants employed to etch through said first layer to function as said etch stop layer; and
generating an end-point signal upon detecting said detectable change. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
-
-
35. A substrate configured to be etched in a plasma processing chamber, comprising:
-
a first layer, and an end-point generating layer disposed below said first layer, said end-point generating layer being selected from a material that produces a detectable change in an absorption rate of a light beam traversing an interior portion of said plasma processing chamber when said end-point generating layer is etched, said end-point generating layer being characterized by an insufficient thickness/selectivity combination to function as an etch stop layer for a plasma etch that also etches through said first layer. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
-
-
49. In a plasma processing chamber, a method for etching through a low-κ
- layer of a layer stack, said low-κ
layer being disposed above an end-point generating layer, said method comprising;introducing a substrate having thereon said layer stack into said plasma processing chamber;
generating a light beam that traverses an interior portion of said plasma processing chamber;
etching through said layer stack, including said low-κ
layer, while monitoring an absorption rate of said light beam by a direct absorption measurement technique, wherein said end-point generating layer is selected from a material that produces a detectable change in said absorption rate when etched, said end-point generating layer being characterized by an insufficient thickness/selectivity combination to function as an etch stop layer for said etching; and
generating an end-point signal upon detecting said detectable change. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71)
- layer of a layer stack, said low-κ
-
72. A method for controlling a plasma etch process in a plasma processing chamber, comprising:
-
introducing a substrate having thereon a layer stack into said plasma processing chamber, said layer stack including a first layer disposed above a second layer;
etching through said first layer while monitoring an absorption rate of a light beam traversing an interior portion of said plasma processing chamber, wherein said second layer is formed of a second layer material that is sufficiently different from a first layer material of said first layer so as to result in a detectable change in said absorption rate when said first layer is etched through; and
generating an end-point signal upon detecting said detectable change. - View Dependent Claims (73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90)
-
Specification