{
  "patent_number": "US 20250172879",
  "country": "US",
  "title": "How to Clean Metal Off Wafers After EUV Chipmaking",
  "original_title": "Metal-compound-removing solvent and method in lithography",
  "summary": "This patent describes a specialized system and cleaning fluid used to precisely remove tiny metal bits from silicon wafers after they've been patterned using extreme ultraviolet light for making advanced computer chips.",
  "what_it_does": "This patent describes a system and method for cleaning semiconductor wafers after they've been processed using Extreme Ultraviolet (EUV) lithography. The system includes a chamber to coat a wafer with a \"metal-containing photoresist material\" (Claim 1). After patterning, \"first nozzles\" apply a \"cleaning fluid\" specifically designed to remove \"metal contaminants\" that come from this photoresist (Claim 1). The cleaning fluid contains a solvent with specific \"Hansen solubility parameters\" (delta D between 13-25, delta P between 3-25, delta H between 4-30) and an acid or base with a defined \"acid dissociation constant\" (Claim 2). \"Second nozzles\" then apply a \"purging fluid\" to further help remove these contaminants (Claim 1). The system can also spin the wafer (Claim 3) and spray fluids onto its backside or edges (Claims 6-9). For example, after an EUV exposure step, a wafer might have trace amounts of tin (Sn) from the photoresist, which this system's specialized cleaning fluid and process would remove to ensure the chip's quality.",
  "what_it_does_not_cover": [
    "Cleaning processes that do not use a metal-containing photoresist material in the EUV lithography step.",
    "Cleaning fluids that do not meet the specified Hansen solubility parameters (delta D, P, H ranges).",
    "Cleaning fluids that do not contain an acid with a pKa between -11 and 4, or a base with a pKa between 9 and 40.",
    "Systems that do not include both distinct cleaning fluid nozzles and distinct purging fluid nozzles.",
    "The use of non-EUV lithography processes for patterning the photoresist."
  ],
  "filed": "2025-01-17",
  "granted": null,
  "expires": "2045-01-17",
  "status": "active",
  "holder": "Taiwan Semiconductor Manufacturing Co TSMC",
  "holder_url": "https://patentbrief.org/company/taiwan-semiconductor-manufacturing-co-tsmc",
  "inventors": [
    {
      "name": "Joy Cheng",
      "url": "https://patentbrief.org/inventor/joy-cheng"
    },
    {
      "name": "Ching-Yu Chang",
      "url": "https://patentbrief.org/inventor/ching-yu-chang"
    },
    {
      "name": "An-Ren Zi",
      "url": "https://patentbrief.org/inventor/an-ren-zi"
    }
  ],
  "times_cited": 0,
  "tags": [
    "semiconductors",
    "consumer_electronics",
    "telecommunications",
    "software"
  ],
  "abstract": "A photoresist layer is coated over a wafer. The photoresist layer includes a metal-containing material. An extreme ultraviolet (EUV) lithography process is performed to the photoresist layer to form a patterned photoresist. The wafer is cleaned with a cleaning fluid to remove the metal-containing material. The cleaning fluid includes a solvent having Hansen solubility parameters of delta D in a range between 13 and 25, delta P in a range between 3 and 25, and delta H in a range between 4 and 30. The solvent contains an acid with an acid dissociation constant less than 4 or a base with an acid dissociation constant greater than 9.",
  "url": "https://patentbrief.org/patent/us/20250172879/metal-compound-removing-solvent-and-method-in-lithography",
  "markdown_url": "https://patentbrief.org/patent/us/20250172879/metal-compound-removing-solvent-and-method-in-lithography/md",
  "google_patents_url": "https://patents.google.com/patent/US20250172879",
  "relatedPatents": []
}