Invention Grant
US08835802B2 Cleaving wafers from silicon crystals 有权
从硅晶体切割晶片

  • Patent Title: Cleaving wafers from silicon crystals
  • Patent Title (中): 从硅晶体切割晶片
  • Application No.: US12162033
    Application Date: 2007-01-24
  • Publication No.: US08835802B2
    Publication Date: 2014-09-16
  • Inventor: Stephen C. Baer
  • Applicant: Stephen C. Baer
  • International Application: PCT/US2007/001911 WO 20070124
  • International Announcement: WO2007/087354 WO 20070802
  • Main IPC: B23K26/00
  • IPC: B23K26/00 B23K26/40 B28D5/00 B28D1/22
Cleaving wafers from silicon crystals
Abstract:
A method of creating thin wafers of single crystal silicon wherein an ingot of single-crystal silicon with a (111) axis is flattened and polished at one end normal to the axis, and a notch with a vertex in the (111) plane is produced on a side or edge of the ingot, such that the distance between this vertex and said end is the desired thickness of a wafer to be cleaved from the ingot and such this vertex is in the desired plane of cleavage. Light of a wavelength able to penetrate into the silicon crystal without significant absorption, when the intensity of the beam is low, but is efficiently absorbed and converted to heat when the intensity of the beam is high, is focused to an elongated volume with an axis of elongation in the desired cleavage plane, parallel to and a short distance from said notch edge. Heating and the resulting transient local expansion of the silicon in this illuminated volume causes tensile stress at the vertex of said notch, substantially normal to the desired cleavage plane, thereby causing fracture of the crystal in the chosen cleavage plane. Movement of the illuminated volume relative to the ingot allows the fracture to propagate across the desired cleavage plane, thereby completely severing the wafer from the rest of the ingot.
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