High selectivity and low stress carbon hardmask by pulsed low frequency RF power
First Claim
1. A method of forming an ashable hard mask, comprising:
- exposing a semiconductor substrate to a process gas comprising a hydrocarbon precursor gas todeposit an ashable hard mask on the substrate by a plasma enhanced chemical vapor deposition (PECVD) process;
igniting a plasma generated by a dual radio frequency (RF) plasma source including a high frequency (HF) component and a low frequency (LF) component; and
pulsing LF power while HF power is constant during deposition,wherein the hydrocarbon precursor gas has a chemical formula of CxHy, where x is an integer between 2 and 10 and y is an integer between 2 and 24.
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Abstract
Methods of forming high etch selectivity, low stress ashable hard masks using plasma enhanced chemical vapor deposition are provided. In certain embodiments, the methods involve pulsing low frequency radio frequency power while keeping high frequency radio frequency power constant during deposition of the ashable hard mask using a dual radio frequency plasma source. According to various embodiments, the low frequency radio frequency power can be pulsed between non-zero levels or by switching the power on and off. The resulting deposited highly selective ashable hard mask may have decreased stress due to one or more factors including decreased ion and atom impinging on the ashable hard mask and lower levels of hydrogen trapped in the ashable hard mask.
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Citations
17 Claims
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1. A method of forming an ashable hard mask, comprising:
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exposing a semiconductor substrate to a process gas comprising a hydrocarbon precursor gas to deposit an ashable hard mask on the substrate by a plasma enhanced chemical vapor deposition (PECVD) process; igniting a plasma generated by a dual radio frequency (RF) plasma source including a high frequency (HF) component and a low frequency (LF) component; and pulsing LF power while HF power is constant during deposition, wherein the hydrocarbon precursor gas has a chemical formula of CxHy, where x is an integer between 2 and 10 and y is an integer between 2 and 24. - View Dependent Claims (2, 3, 4)
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5. The method of forming an amorphous carbon layer, comprising:
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exposing a semiconductor substrate to a process gas comprising a hydrocarbon precursor gas; depositing on the substrate an amorphous carbon layer by a plasms enhanced chemical vapor deposition (PECVD) process using a plasma generated by a dual radio frequency (RF) plasma source including a high frequency (HF) component and a low frequency (LF) component, wherein HF power is constant while LF power is pulsed during deposition, and wherein the hydrocarbon precursor gas has a chemical formula of CxHy, where x is an integer between 2 and 10 and y is an integer between 2 and 24. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification