Methods for etching doped oxides in the manufacture of microfeature devices
First Claim
1. A method for forming capacitors on a microfeature workpiece, the workpiece including a plurality of conductive plugs, a first nitride layer over the conductive plugs, a dielectric layer over the first nitride layer, and a second nitride layer over the dielectric layer, the method comprising:
- patterning and etching the second nitride layer to form a mask over the dielectric layer;
forming a plurality of first openings in the dielectric layer with a first etching process, wherein the dielectric layer includes a doped oxide material;
forming a plurality of second openings in the first nitride layer with a second etching process, the individual second openings exposing at least a portion of the individual conductive plugs;
depositing a first conductive layer in at least a portion of the individual openings and in electrical contact with corresponding conductive plugs, wherein the first conductive layer includes TiN;
depositing a second conductive layer over at least a portion of the first conductive layer in the individual openings, wherein the second conductive layer includes polysilicon; and
removing at least substantially all the dielectric layer from the workpiece with a third etching process, wherein the third etching process includes an etchant comprising DI;
HF and an acid to provide a pH of the etchant such that the etchant includes (a) a selectivity of phosphosilicate glass (PSG) to nitride of greater than 250;
1, and (b) an etch rate through PSG of greater than 9,000 Å
/minute.
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Abstract
Methods for selectively etching doped oxides in the manufacture of microfeature devices are disclosed herein. An embodiment of one such method for etching material on a microfeature workpiece includes providing a microfeature workpiece including a doped oxide layer and a nitride layer adjacent to the doped oxide layer. The method include selectively etching the doped oxide layer with an etchant comprising DI:HF and an acid to provide a pH of the etchant such that the etchant includes (a) a selectivity of phosphosilicate glass (PSG) to nitride of greater than 250:1, and (b) an etch rate through PSG of greater than 9,000 Å/minute.
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Citations
12 Claims
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1. A method for forming capacitors on a microfeature workpiece, the workpiece including a plurality of conductive plugs, a first nitride layer over the conductive plugs, a dielectric layer over the first nitride layer, and a second nitride layer over the dielectric layer, the method comprising:
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patterning and etching the second nitride layer to form a mask over the dielectric layer; forming a plurality of first openings in the dielectric layer with a first etching process, wherein the dielectric layer includes a doped oxide material; forming a plurality of second openings in the first nitride layer with a second etching process, the individual second openings exposing at least a portion of the individual conductive plugs; depositing a first conductive layer in at least a portion of the individual openings and in electrical contact with corresponding conductive plugs, wherein the first conductive layer includes TiN; depositing a second conductive layer over at least a portion of the first conductive layer in the individual openings, wherein the second conductive layer includes polysilicon; and removing at least substantially all the dielectric layer from the workpiece with a third etching process, wherein the third etching process includes an etchant comprising DI;
HF and an acid to provide a pH of the etchant such that the etchant includes (a) a selectivity of phosphosilicate glass (PSG) to nitride of greater than 250;
1, and (b) an etch rate through PSG of greater than 9,000 Å
/minute. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification