Electrostatic particle removal and characterization

{
  "publication_number": "US5584938A",
  "country": "US",
  "kind": "A",
  "title": "Electrostatic particle removal and characterization",
  "abstract": "An electrostatic decontamination method and decontamination device (10) is disclosed for decontaminating the surface of a semiconductor substrate. The decontamination device (10) includes particle ionizing device (24) that charges contaminating particles (26) on the surface of semiconductor substrate (16) thereby creating ionized particles. Decontamination device (10) also includes substrate biasing device (12) for creating a charge accumulation layer (14) at the top of semiconductor substrate (16) so that the charge accumulation layer (14) has the same charge sign as the ionized particles. In addition, the invention analytically characterizes particles using contaminating particle isolator (44) which contains a particle ionizing device (24) that charges contaminating particles (26) on the surface of semiconductor substrate (16) thereby creating ionized particles. Contaminating particle isolator (44) includes substrate biasing device (12) operable to create charge accumulation layer (14) at the top of semiconductor substrate (16) so that the charge accumulation layer (14) has the same charge sign as the ionized particles. Contaminating particle isolator (44) also includes particle collector (46) that collects the ionized particles. This permits characterizing the particles to determine their chemical composition.",
  "claims": [
    "1. A method for electrostatically decontaminating the surface of a semiconductor substrate having contaminating particles thereon the method comprising the steps of: ionizing the contaminating particles on the surface of the substrate to form ionized particles; producing a charge accumulation layer at the top of the semiconductor substrate to electrostatically separate the ionized particles from the surface of said semiconductor substrate, the charge accumulation layer having the same charge sign as the ionized particles:, wherein said step of producing a charge accumulation laver at the top of a semiconductor substrate comprises the step of charfling an insulated wafer chuck and resting the substrate on top of the insulated wafer chuck.",
    "2. The method of claim 1 wherein said step of ionizing the contaminating particles comprises the step of ionizing the contaminating particles using deep ultraviolet photons.",
    "3. The method of claim 1 wherein said step of ionizing the contaminating particles comprises the step of ionizing the contaminating particles using a low energy, broad area flux of electrons.",
    "4. A method for electrostatically decontaminating the surface of a semiconductor substrate having contaminating particles thereon the method comprising the steps of: passing an inert gas over said surface; ionizing the contaminating particles on the surface of the substrate to form ionized particles; producing a charge accumulation layer at the top of the semiconductor substrate to electrostatically Separate the ionized particles from the surface of said semiconductor substrate, the charge accumulation layer having the same charge sign as the ionized particles; wherein said step of producing a charge accumulation layer at the top of a semiconductor substrate comprises the step of positively charging an insulated wafer chuck and resting the substrate on top of the insulated wafer chuck.",
    "5. A method for electrostatically decontaminating the surface of a semiconductor substrate having contaminating particles thereon the method comprising the steps of: ionizing the contaminating particles on the surface of the substrate to form ionized particles; producing a charge accumulation layer at the top of the semiconductor substrate to electrostatically separate the ionized particles from the surface of said semiconductor substrate, the charge accumulation layer having the same charge sign as the ionized particles; wherein said step of producing a charge accumulation layer at the top of the semiconductor substrate comprises negatively charging an insulated wafer chuck and resting the substrate on top of the insulated wafer chuck.",
    "6. A method for analytically characterizing particles contaminating a semiconductor substrate comprising the steps of: ionizing the contaminating particles on the surface of said substrate to form ionized particles; producing a charge accumulation layer at the top of the semiconductor substrate to electrostatically separate the ionized particles from the surface of said semiconductor substrate, the charge accumulation layer having the same charge sign as the ionized particles; collecting the ionized particles that were separated from the semiconductor surface using a particle collector for collecting the ionized particles separated from the surface of said semiconductor substrate; and determining the chemical composition of the collected ionized particles wherein said step of producing a charge accumulation layer at the semiconductor substrate comprises charging an insulated wafer chuck and resting the substrate on top of the insulated wafer chuck.",
    "7. The method of claim 6 wherein said step of ionizing the contaminating particles further comprises the step of ionizing the contaminating particles using deep ultraviolet photons.",
    "8. The method of claim 6 wherein said step of producing a charge accumulation layer at the semiconductor substrate comprises positively charging an insulated wafer chuck and resting the substrate on top of the insulated wafer chuck.",
    "9. The method of claim 6 and further comprising the step of: removing the ionized particles from the proximity of the semiconductor substrate using a flowing gas inert to the semiconductor substrate.",
    "10. The method of claim 6 wherein said step of ionizing the contaminating particles further comprising the step of ionizing the contaminating particles using deep ultraviolet photons; and said step of producing a charge accumulation layer at the top of said semiconductor substrate further comprises positively charging an insulated wafer chuck and resting the substrate on top of the wafer chuck.",
    "11. The method of claim 6 wherein said step of ionizing the contaminating particles further comprises the step of ionizing the contaminating particles using a low energy, broad area flux of electrons.",
    "12. The method of claim 6 wherein said step of producing a charge accumulation layer at the top of the semiconductor substrate further comprises the step of negatively charging an insulated wafer chuck and resting the substrate on top of the wafer chuck.",
    "13. The method of claim 6 wherein said step of ionizing the contaminating particles further comprises the step of ionizing the contaminating particles using a low energy, broad area flux of electrons; and said step of producing a charge accumulation layer at the top of the substrate comprises negatively charging an insulated wafer chuck and resting the substrate on top of the wafer chuck."
  ],
  "cpc": [
    "H10P 72/0406",
    "B08B 6/00",
    "Y10S 422/906",
    "Y10T 436/25375"
  ],
  "assignees": [
    "TEXAS INSTRUMENTS INC"
  ],
  "filing_date": "1993-12-10",
  "publication_date": "1996-12-17",
  "grant_date": "1996-12-17",
  "priority_date": "1993-12-10",
  "application_number": "US-16632193-A",
  "family_id": "22602763",
  "citations": [
    "DE3904969A1",
    "US4812662A",
    "US5024968A",
    "US5099557A",
    "US5125124A",
    "US5187635A"
  ]
}