High selectivity BPSG to TEOS etchant
First Claim
1. A method of forming an opening in a semiconductor device having a first barrier layer and a second barrier layer thereover, the method comprising:
- etching the second barrier layer with a first etchant selective to the second barrier layer over the first barrier layer, the first etchant comprising a fluoride-containing solution and an organic acid selected from the group consisting of oxalic acid and formic acid to form a via in the second barrier layer having substantially vertical sidewalls and to expose the first barrier layer; and
forming an opening extending from a lowermost portion of the first barrier layer to an uppermost portion of the second barrier layer by applying a second etchant to the via.
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Accused Products
Abstract
Methods of selectively etching BPSG over TEOS are disclosed. In one embodiment, a TEOS layer may be used to prevent contamination of other components in a semiconductor device by the boron and phosphorous in a layer of BPSG deposited over the TEOS layer. An etchant of the present invention may be used to etch desired areas in the BPSG layer, wherein the high selectivity for BPSG to TEOS of etchant would result in the TEOS layer acting as an etch stop. A second etchant may be utilized to etch the TEOS layer. The second etchant may be less aggressive and, thus, not damage the components underlying the TEOS layer.
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Citations
14 Claims
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1. A method of forming an opening in a semiconductor device having a first barrier layer and a second barrier layer thereover, the method comprising:
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etching the second barrier layer with a first etchant selective to the second barrier layer over the first barrier layer, the first etchant comprising a fluoride-containing solution and an organic acid selected from the group consisting of oxalic acid and formic acid to form a via in the second barrier layer having substantially vertical sidewalls and to expose the first barrier layer; and forming an opening extending from a lowermost portion of the first barrier layer to an uppermost portion of the second barrier layer by applying a second etchant to the via. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of selectively etching a barrier layer on a semiconductor device, the method comprising:
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contacting a semiconductor device having a barrier layer overlying tetraethyl orthosilicate with a first solution comprising a fluoride-containing solution and an organic acid selected from the group consisting of oxalic acid and formic acid to form a partial opening having substantially vertical sidewalls extending from an upper portion of the tetraethyl orthosilicate to an upper portion of the barrier layer; and etching the tetraethyl orthosilicate with a second solution to form a full opening having substantially vertical sidewalls extending from a lower portion of the tetraethyl orthosilicate to the upper portion of the barrier layer. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification