Low-pressure removal of photoresist and etch residue
First Claim
1. A method of in-situ ashing, comprising:
- introducing a process gas containing an oxygen-containing gas;
generating a plasma in a plasma processing chamber;
exposing a substrate to the plasma, the substrate residing on top of a substrate holder;
performing a first ashing step by applying a first bias to the substrate holder; and
performing a second ashing step by applying a second bias to the substrate holder, wherein the second bias is greater than the first bias and the chamber pressure in the second ashing step is less than 20 mTorr.
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Abstract
A method is provided for low-pressure plasma ashing to remove photoresist remnants and etch residues that are formed during preceding plasma etching of dielectric layers. The ashing method uses a two-step plasma process involving an oxygen-containing gas, where low or zero bias is applied to the substrate in the first cleaning step to remove significant amount of photoresist remnants and etch residues from the substrate, in addition to etching and removing detrimental fluoro-carbon residues from the chamber surfaces. An increased bias is applied to the substrate in the second cleaning step to remove the remains of the photoresist and etch residues from the substrate. A chamber pressure less than 20 mTorr is utilized in the second cleaning step. The two-step process reduces the memory effect commonly observed in conventional one-step ashing processes. A method of endpoint detection can be used to monitor the ashing process.
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Citations
43 Claims
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1. A method of in-situ ashing, comprising:
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introducing a process gas containing an oxygen-containing gas;
generating a plasma in a plasma processing chamber;
exposing a substrate to the plasma, the substrate residing on top of a substrate holder;
performing a first ashing step by applying a first bias to the substrate holder; and
performing a second ashing step by applying a second bias to the substrate holder, wherein the second bias is greater than the first bias and the chamber pressure in the second ashing step is less than 20 mTorr. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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21. The method according to claim 21, wherein the fluorine-containing species is fluorine.
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41. A method of in-situ ashing, comprising:
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introducing a process gas containing O2 gas;
generating a plasma in a plasma processing chamber by applying RF power throug an impedance match network to an upper plate of a plasma source;
exposing a substrate to the plasma, the substrate containing a low-k material, photoresist, or etch residues, or a combination thereof, and residing on top of a substrate holder;
performing a first ashing step by applying a first bias between about 0 W and about 100 W to the substrate holder; and
performing a second ashing step by applying a second bias between about 50 W and about 1000 W to the substrate holder, wherein the second bias being greater than the first bias and the chamber pressure in the second ashing step being less than 20 mTorr. - View Dependent Claims (42, 43)
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Specification
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- Resources
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Current AssigneeTokyo Electron Limited
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Original AssigneeTokyo Electron Limited
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InventorsNishimura, Eiichi, Balasubramaniam, Vaidyanathan, Inazawa, Koichiro, Inazawa, Rie, Hagihara, Masaaki
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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current216/59
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CPC Class CodesG03F 7/427 using plasma means onlyH01L 21/02063 the processing being the fo...H01L 21/31138 by dry-etching
