Method of Etching a High Aspect Ratio Contact
First Claim
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1. A method of etching an opening in a dielectric layer, comprising:
- forming a plasma etching gas from C4F6, C4F8 or a mixture of C4F6 and C4F8, an oxygen source gas, an inert gas, and C2F4; and
etching the opening through the dielectric layer to an underlying substrate with said plasma etching gas, wherein a conformal polymer layer is maintained along sidewalls of the opening during said etching.
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Abstract
Methods and an etch gas composition for etching a contact opening in a dielectric layer are provided. Embodiments of the method use a plasma generated from an etch gas composed of C4F8 and/or C4F6, an oxygen source, and a carrier gas in combination with tetrafluoroethane (C2F4) or a halofluorocarbon analogue of C2F4.
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Citations
23 Claims
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1. A method of etching an opening in a dielectric layer, comprising:
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forming a plasma etching gas from C4F6, C4F8 or a mixture of C4F6 and C4F8, an oxygen source gas, an inert gas, and C2F4; and etching the opening through the dielectric layer to an underlying substrate with said plasma etching gas, wherein a conformal polymer layer is maintained along sidewalls of the opening during said etching. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of etching an opening in a dielectric layer, comprising:
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forming plasma etching gas from C4F6, C4F8 or a mixture thereof at a flow rate of about 50-70 sccm, an oxygen source gas at a flow rate of about 20-40 sccm, an inert diluent gas at a flow rate of about 900-1300 sccm, and C2F4 at a flow rate of about 80-100 sccm; and etching the opening through the dielectric layer to an underlying substrate with said plasma etching gas, wherein a conformal polymer layer is maintained along sidewalls of the opening during said etching.
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12. A method of etching an opening in a dielectric layer comprising:
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applying a plasma etching gas to etch the dielectric layer to an underlying substrate, the plasma etching gas formed from C4F6, C4F8 or mixture thereof, an oxygen source gas, an inert diluent gas, and a halofluorocarbon selected from the group consisting of C2F4Br2, C2F4I2 and CF2I2; wherein a conformal polymer layer is maintained along sidewalls of the opening during etching. - View Dependent Claims (13, 14, 15, 16, 17)
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- 18. An etch gas for etching a dielectric material comprising at least one of C4F6 and C4F8, and an oxygen source gas, an inert diluent gas, and C2F4 in amounts effective to form a plasma etching gas to etch an opening through the dielectric layer while maintaining a conformal polymer layer on sidewalls of the opening during said etching.
- 21. An etch gas for plasma etching a dielectric layer, comprising at least one of C4F6 and C4F8, an oxygen source gas, an inert carrier gas, and a halofluorocarbon selected from the group consisting of C2F4Br2, C2F4I2 and CF2I2 in amounts effective to form a plasma etching gas to etch an opening through a dielectric layer while maintaining a conformal polymer layer on sidewalls of the opening during said etching.
Specification