Novellus Systems Incorporated

Zhiyuan Fang

Jon Henri

Pramod Subramonium

Yongsik Yu

Shawn D Hancock

Elizabeth Apen

Dan Vitkavage

Mike Pierce

Keith Fox

Provided are plasma enhanced chemical vapor deposition methods of depositing smooth and conformal ashable hard mask films on substrates containing raised or recessed features. The methods involve using precursors having relatively high C:H ratios, such as acetylene (C:H ratio of 1), and plasmas having low ion energies and fluxes. According to various embodiments, the methods involve depositing smooth ashable hard mask films using high frequency radio frequency-generated plasmas with no low frequency component and/or relatively high pressures. Also provided are methods of depositing ashable hard mask films having good selectivity and improved side wall coverage and roughness. The methods involve depositing a first ashable hard mask film on a substrate having a feature using a process optimized for selectivity and/or optical properties and then depositing a smoothing layer on the first ashable hard mask film using an HF-only process.

Methods of depositing smooth and conformal ashable hard mask films

Films having high hermeticity and a low dielectric constant can be used as copper diffusion barrier films, etch stop films, CMP stop films and other hardmasks during IC fabrication. Hermetic films can protect the underlying layers, such as layers of metal and dielectric, from exposure to atmospheric moisture and oxygen, thereby preventing undesirable oxidation of metal surfaces and absorption of moisture by a dielectric. Specifically, a bi-layer film having a hermetic bottom layer composed of hydrogen doped carbon and a low dielectric constant (low-k) top layer composed of low-k silicon carbide (e.g., high carbon content hydrogen doped silicon carbide) can be employed. Such bi-layer film can be deposited by PECVD methods on a partially fabricated semiconductor substrate having exposed layers of dielectric and metal.

Diffusion barrier and etch stop films

Improved methods and apparatuses for removing residue from the interior surfaces of the deposition reactor are provided. The methods involve increasing availability of cleaning reagent radicals inside the deposition chamber by generating cleaning reagent radicals in a remote plasma generator and then further delivering in-situ plasma energy while the cleaning reagent mixture is introduced into the deposition chamber. Certain embodiments involve a multi-stage process including a stage in which the cleaning reagent mixture is introduced at a high pressure (e.g., about 0.6 Torr or more) and a stage the cleaning reagent mixture is introduced at a low pressure (e.g., about 0.6 Torr or less).

Plasma clean method for deposition chamber

Provided are plasma enhanced chemical vapor deposition methods of depositing smooth and conformal ashable hard mask films on substrates containing raised or recessed features. The methods involve using precursors having relatively high C:H ratios, such as acetylene (C:H ratio of 1), and plasmas having low ion energies and fluxes. According to various embodiments, the methods involve depositing smooth ashable hard mask films using high frequency radio frequency-generated plasmas with no low frequency component and/or relatively high pressures (e.g., 2-5 Torr). Also provided are methods of depositing ashable hard mask films having good selectivity and improved side wall coverage and roughness. The methods involve depositing a first ashable hard mask film on a substrate having a feature using a process optimized for selectivity and/or optical properties and then depositing a smoothing layer on the first ashable hard mask film using an HF-only process.

A method for forming a PECVD deposited amorphous carbon or ashable hard mask (AHM) in a trench or a via with less than 30% H content at a process temperature below 500&#xb0; C., e.g., about 400&#xb0; C. produces low H content hard masks with high selectivity and little or no hard mask on the sidewalls. The deposition method utilizes a pulsed precursor delivery with a plasma etch while the precursor flow is off.

Pulsed PECVD method for modulating hydrogen content in hard mask

The present invention addresses this need by providing a method for forming transparent PECVD deposited ashable hardmasks (AHMs) that have high plasma etch selectivity to underlying layers. Methods of the invention involve depositing the AHM using dilute hydrocarbon precursor gas flows and/or low process temperatures. The AHMs produced are transparent (having absorption coefficients of less than 0.1 in certain embodiments). The AHMs also have the property of high selectivity of the hard mask film to the underlying layers for successful integration of the film, and are suitable for use with 193 nm generation and below lithography schemes wherein high selectivity of the hard mask to the underlying layers is required. The lower temperature process also allows reduction of the overall thermal budget for a wafer.

Methods of depositing highly selective transparent ashable hardmask films

The present invention provides PECVD methods for forming stable and hermetic ashable hard masks (AHMs). The methods involve depositing AHMs using dilute hydrocarbon precursor gas flows and/or high LFRF/HFRF ratios. In certain embodiments, the AHMs are transparent and have high etch selectivities. Single and dual layer hermetic AHM stacks are also provided. According to various embodiments, the dual layer stack includes an underlying AHM layer having tunable optical properties and a hermetic cap layer.

Methods of depositing stable and hermetic ashable hardmask films

A method for forming a PECVD deposited ashable hardmask (AHM) with less than 30% H content at a process temperature below 500&#xb0; C., e.g., about 400&#xb0; C. produces low H content hard masks having the property of high selectivity of the hard mask film to the underlying layers for successful integration of the film, and are suitable for use with 193 nm generation and below lithography schemes wherein high selectivity of the hard mask to the underlying layers is required. The low temperature, low H films are produced by use of a pulsed film hydrocarbon precursor plasma treatment that reduces the amount of hydrogen incorporated in the film and therefore drives down the etch rate of the hard mask thus increasing the selectivity. The lower temperature process also allows reduction of the overall thermal budget for a wafer.

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West Linn, OR, United States of America

Zhiyuan Fang