Using hydrogen gas in a post-etch radio frequency-plasma contact cleaning process
First Claim
1. A method of cleaning byproducts from a semiconductor structure, said semiconductor structure comprising:
- a first layer consisting essentially of borophosphosilicate glass (BPSG) formed on top of a second layer consisting essentially of silicon, and a contact hole formed by etching through said first layer to said second layer, said byproducts being formed by said etching and being located in said contact hole, said byproducts comprising silicon-containing residues and damaged silicon;
said method comprising;
providing a reaction chamber, said reaction chamber comprising a platen;
placing said structure on said platen;
creating a plasma, said plasma comprising a gas mixture, said gas mixture comprising hydrogen gas and a fluorine gas; and
causing said plasma to contact said byproducts.
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Accused Products
Abstract
Provided is a method for removing etch byproducts inside a contact hole while minimizing lateral etching of the contact hole. After an etching process, a wafer having a contact hole is placed inside a plasma reaction chamber. The contact hole contains etch byproducts that may degrade the quality of electrical connections. A radio frequency (RF) source creates a RF field inside the reaction chamber. A gas mixture containing chemicals that are reactive with the etch byproducts is introduced into the reaction chamber. The gas mixture becomes ionized by the RF field and reacts with the etch byproducts in the contact hole, removing the etch byproducts. The gas mixture may include approximately 10-60 vol. % hydrogen gas, a gas that reacts with the etch byproducts (e.g., NF3), and nitrogen. The hydrogen gas at least significantly reduces lateral etching of the contact hole by the reactive gas.
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Citations
16 Claims
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1. A method of cleaning byproducts from a semiconductor structure, said semiconductor structure comprising:
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a first layer consisting essentially of borophosphosilicate glass (BPSG) formed on top of a second layer consisting essentially of silicon, and a contact hole formed by etching through said first layer to said second layer, said byproducts being formed by said etching and being located in said contact hole, said byproducts comprising silicon-containing residues and damaged silicon;
said method comprising;
providing a reaction chamber, said reaction chamber comprising a platen;
placing said structure on said platen;
creating a plasma, said plasma comprising a gas mixture, said gas mixture comprising hydrogen gas and a fluorine gas; and
causing said plasma to contact said byproducts. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
a platen coupled to a radio frequency source that creates a radio frequency field inside said reaction chamber;
a gas distribution plate through which gases are introduced into said reaction chamber to become ionized by said radio frequency field; and
a vacuum pump for controlling the pressure inside said reaction chamber.
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13. The method of claim 12, wherein said reaction chamber further comprises a means for controlling the temperature of said platen.
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14. The method of claim 1, wherein said creating a plasma comprises introducing said hydrogen gas at a flowrate of about 200-500 sccm, introducing NF3 at a flowrate of about 30 sccm, and introducing N2 at a flowrate of about 200-500 sccm.
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15. A method of cleaning byproducts from a semiconductor structure, said semiconductor structure comprising:
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a first layer formed on top of a second layer, said first layer consisting essentially of a material selected from the group consisting of phosphosilicate glass (PSG), borosilicate glass (BSG), borophosphosilicate glass (BPSG), and spin-on-glass, said second layer consisting essentially of silicon, and a contact hole formed by etching through said first layer to said second layer, said byproducts being formed by said etching and being located in said contact hole, said by products comprising silicon-containing residues and damaged silicon;
said method comprising;
providing a reaction chamber, said reaction chamber comprising a platen;
placing said structure on said platen;
creating a plasma, said plasma comprising a gas mixture, said gas mixture comprising hydrogen gas and a fluorine gas; and
causing said plasma to contact said byproducts.
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16. A method of cleaning byproducts from a semiconductor structure, said semiconductor structure comprising:
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a first layer consisting essentially of silicon nitride formed on top of a second layer consisting essentially of silicon, a third layer consisting essentially of borophosphosilicate glass (BPSG) formed on top of said first layer, and a contact hole formed by etching through said first and third layers to said second layer, said byproducts being formed by said etching and being located in said contact hole, said by products comprising silicon-containing residues and damaged silicon;
said method comprising; providing a reaction chamber, said reaction chamber comprising a platen;
placing said structure on said platen;
creating a plasma, said plasma comprising a gas mixture, said gas mixture comprising hydrogen gas and a fluorine gas; and
causing said plasma to contact said byproducts.
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Specification