Flowable low-k dielectric gapfill treatment

{
  "publication_number": "US9362107B2",
  "country": "US",
  "kind": "B2",
  "title": "Flowable low-k dielectric gapfill treatment",
  "abstract": "Methods are described for forming a flowable low-k dielectric film on a patterned substrate. The film may be a silicon-carbon-oxygen (Si - C - O) layer in which the silicon and carbon constituents come from a silicon and carbon containing precursor while the oxygen may come from an oxygen-containing precursor activated in a remote plasma region. Shortly after deposition, the silicon-carbon-oxygen layer is treated by exposure to a hydrogen-and-nitrogen-containing precursor such as ammonia prior to curing. The treatment may remove residual moisture from the silicon-carbon-oxygen layer and may make the lattice more resilient during curing and subsequent processing. The treatment may reduce shrinkage of the silicon-carbon-oxygen layer during subsequent processing.",
  "claims": [
    "1. A method of processing a low-k dielectric film, the method comprising: forming a silicon-carbon-oxygen film on a substrate, wherein the silicon-carbon-oxygen film comprises silicon, carbon and oxygen; exposing the silicon-carbon-oxygen film to an atmosphere comprising a hydrogen-and-nitrogen-containing precursor; exposing the silicon-carbon-oxygen film to at least one of UV-light or an electron beam after exposing the silicon-carbon-oxygen film to the atmosphere comprising the hydrogen-and-nitrogen-containing precursor, wherein the atmosphere comprising the hydrogen-and-nitrogen-containing precursor is devoid of oxygen.",
    "2. The method of claim 1 wherein the hydrogen-and-nitrogen-containing precursor consists only of hydrogen and nitrogen.",
    "3. The method of claim 1 wherein the silicon-carbon-oxygen film contains no elements other than silicon, carbon, hydrogen and oxygen prior to the operation of exposing the silicon-carbon-oxygen film to an atmosphere comprising a hydrogen-and-nitrogen-containing precursor.",
    "4. The method of claim 1 wherein the silicon-carbon-oxygen film contains no elements other than silicon, carbon, nitrogen, hydrogen and oxygen following the operation of exposing the silicon-carbon-oxygen film to an atmosphere comprising a hydrogen-and-nitrogen-containing precursor.",
    "5. The method of claim 1 wherein a temperature of the substrate while exposing the silicon-carbon-oxygen film to the atmosphere comprising the hydrogen-and-nitrogen-containing precursor is less than 150° C.",
    "6. A method of filling a trench, the method comprising: transferring a patterned substrate comprising the trench into a substrate processing region of a substrate processing chamber; flowing an oxygen-containing precursor into a remote plasma region while igniting a remote plasma to form a radical-oxygen precursor; flowing a silicon-and-carbon-containing precursor into the substrate processing region without first passing the silicon-and-carbon-containing precursor through any plasma; flowing the radical-oxygen precursor into the substrate processing region; combining the silicon-and-carbon-containing precursor and the radical-oxygen precursor in the substrate processing region to form a low-k dielectric film on the patterned substrate, wherein a portion of the low-k dielectric film deposits on the patterned substrate and flows along a surface of the patterned substrate during formation of the low-k dielectric film to fill the trench; and flowing a hydrogen-and-nitrogen-containing precursor into the substrate processing region to treat the patterned substrate and form a treated low-k dielectric film.",
    "7. The method of claim 6 wherein the low-k dielectric film has a dielectric constant of between 2.2 and 3.0 in the trench of a completed device.",
    "8. The method of claim 6 wherein the silicon-and-carbon-containing precursor possesses a Si - O to Si ratio of less than 3.",
    "9. The method of claim 6, wherein the silicon-and-carbon-containing precursor possesses a Si - O to Si ratio of 1.",
    "10. The method of claim 6 further comprising an operation of curing the treated low-k dielectric film by exposing the treated low-k dielectric film to one or both of UV light and e-beam radiation.",
    "11. The method of claim 6 wherein the silicon-and-carbon-containing precursor is octamethylcyclotetrasiloxane or tetramethylcyclotetrasiloxane.",
    "12. A method of filling a trench, the method comprising: transferring a patterned substrate comprising the trench into a substrate processing region of a substrate processing chamber; flowing molecular oxygen into a remote plasma region while igniting a remote plasma to form plasma effluents; flowing the plasma effluents into the substrate processing region through through-holes in a showerhead disposed and forming a border between the remote plasma region and the substrate processing region; flowing a silicon-and-carbon-containing precursor into the substrate processing region without first passing the silicon-and-carbon-containing precursor through a plasma, wherein the silicon-and-carbon-containing precursor has a Si - O:Si ratio of less than 3; combining the silicon-and-carbon-containing precursor and the plasma effluents in the substrate processing region to form a low-k dielectric film on the patterned substrate; flowing ammonia into the substrate processing region to treat the patterned substrate and form a treated low-k dielectric film, wherein the substrate processing region is devoid of plasma; and curing the treated low-k dielectric film by exposure to ultraviolet light.",
    "13. The method of claim 12 wherein the silicon-and-carbon-containing precursor has a Si - O:Si ratio of 1.",
    "14. The method of claim 12 wherein the patterned substrate is not exposed to external atmosphere from transferring the patterned substrate to flowing ammonia into the substrate processing region to treat the patterned substrate."
  ],
  "description_excerpt": "Embodiments of the invention relate to flowably depositing low-k dielectric into substrate gaps.\n\nThe miniaturization of semiconductor circuit elements has reached a point where feature sizes of 28 nm, 22 nm, and even 14 nm are fabricated on a commercial scale. As the dimensions continue to get smaller, new challenges arise for process steps like filling a gap between circuit elements with a dielectric material that avoids electrical cross-talk. As the width between the elements continues to shrink, the gap between them often gets taller and narrower, making the gap difficult to fill without the dielectric material getting stuck to create voids or weak seams. Conventional chemical vapor deposition (CVD) techniques often experience an overgrowth of material at the top of the gap before it has been completely filled. This can create a void or seam in the gap where the depositing dielectric material has been prematurely cut off by the overgrowth; a problem sometimes referred to as breadloafing.\n\nOne solution to the breadloafing problem has been to use liquid precursors for the dielectric starting materials that more easily flow into the gaps. A technique currently in commercial use for doing this is called spin-on-glass (SOG). More recently, techniques have been developed that impart flowable characteristics to dielectric materials deposited by CVD. These techniques can deposit flowable precursors to fill a tall, narrow gap while reducing an incidence of creating voids or weak seams.",
  "cpc": [
    "H10P 14/6922",
    "C23C 16/30",
    "C23C 16/56",
    "H01L 21/02126",
    "H01L 21/02216",
    "H01L 21/02274",
    "H01L 21/02348",
    "H01L 21/02351",
    "H01L 21/76224",
    "H01L 21/76837",
    "H10P 14/6336",
    "H10P 14/6529",
    "H10P 14/6538",
    "H10P 14/6539",
    "H10W 10/014",
    "H10W 10/17",
    "H10W 20/098"
  ],
  "ipc": [
    "H01L 21/02",
    "H01L 21/762",
    "H01L 21/768"
  ],
  "assignees": [
    "Applied Materials Inc"
  ],
  "inventors": [
    "Kiran V. Thadani",
    "Abhijit Basu Mallick",
    "Sanjay Kamath"
  ],
  "filing_date": "2014-09-30",
  "publication_date": "2016-06-07",
  "grant_date": "2016-06-07",
  "priority_date": "2014-09-30",
  "application_number": "US-201414502492-A",
  "family_id": "55585237",
  "cited_by_count": 433,
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}