Surface Layer Damage of Silicon Wafers Sliced by Wire Saw Process

Abstract

Wire saw process is widely used in the machining of hard and brittle materials with low surface damage and high efficiency. Cutting of silicon wafers in integrated circuit (IC), semiconductor and photovoltaic solar industries is also generally using wire saw process. However, the surface layer damage induced by wire saw process will seriously decrease the wafer quality and increase the process time and production costs of the post grinding and polishing. The surface layer qualities of the silicon wafers sawed by the different wire saw processes was investigated in this paper. The characteristics of surface roughness, surface topography and subsurface damage of silicon wafers sliced by the fixed abrasive and the loose abrasive wire sawing respectively were compared and the corresponding reasons were analyzed.

General Molecular Dynamics Approach to Understand the Mechanical Anisotropy of Monocrystalline Silicon under the Nanoscale Effects of Point Defect

“…In solar cell production, monocrystalline silicon is fabricated via the floating zone or Czochralski methods [ 1 ] first; then, it is sent to the cutting process to produce silicon wafers. Diamond-wire cutting techniques are used to process silicon wafers due to the advantages of low surface damage and high efficiency [ 2 , 3 ]. However, diamond-wire cutting causes edge collapse, hidden crack and surface damage in the wafer fabrication and then results in mechanical problems [ 4 ] due to the brittleness and crystal defects of silicon.…”

Recent Advances in Precision Diamond Wire Sawing Monocrystalline Silicon

“…Additionally, increasing the wire saw speed and improving the uniform distribution of grains on the wire surface led to a continuous reduction in surface roughness and subsurface damage. Kang et al [148] observed distinct differences in subsurface microcrack depth between the fixed and free abrasive cutting methods when a constant wire speed and feed rate were maintained. The fixed diamond wire exhibited , (a,c) shows the sawn surface in the crystallographic plane {100}, (b,d) location of median microcracks in the subsurface region [113].…”

The impact of saw mark direction on the fracture strength of thin (120 µm) monocrystalline silicon wafers for photovoltaic cells

“…However, material removal or chipping in the LASS process generates long microcracks inside the wafers, which degrades their mechanical strength and constitutes a major hurdle in further reducing the wafer thickness in LASS. [10][11][12][13] Blake et al 14) proposed the advantage of cutting brittle material (such as Si crystals) in the ductile mode, showing that the removal or chipping of material in this mode reduces wafer breakage and makes it possible to saw thinner wafers. 15,16) Several previous studies on Si crystals showed that applying sufficient hydrostatic pressure or scratching= indenting the surface and subsurface layers of Si allows the transition from elastic to plastic mode (ductile mode).…”