Fixed Abrasives Diamond Wire for SiliconIn recent years, solar power generation has received more and more attention from people and has been popularized. Due to the high photoelectric conversion efficiency, monocrystalline silicon has been used as substrate material for solar panels. Using the multi-wire cutting technology, Monocrystalline silicon rod can be directly cut into more than 3,000 wafers one-time. In the past, mono-crystal silicon was cut by using free-abrasive wire cutting technique. The principle of cutting was driven by a slurry containing SiC abrasive grains (5 to 10 μm) for cutting with a fine steel wire (approximately 0.12 mm). With the development of society, monocrystalline silicon is cut using a fixed diamond wire, and it basically replaces the free abrasive cutting method. Fixed diamond wires are mostly made by electroplating method, and the cutting efficiency is 3 to 5 times that of the free abrasive wire cutting method. Moreover, since the diamond particles are fixed, the cutting seam loss is smaller, and the wafer cutting thickness is also more thinner.
In order to obtain thinner silicon wafers and reduce the weight of solar panels, high-precision processing and reduction of the silicon wafer crushing rate are critical; Ensoll loop diamond wire, such as 0.6 mm OD, greatly reduce the surface roughness.
Under the different conditions, high-speed monocrystalline silicon cutting tests have been performed:
(1) The use of better quality diamond helps to improve the surface finish;
(2) The increase of the number of processing makes the surface of the diamond round, and reduces the depth of surface damage layer and wire mark;
(3) Raman spectra show that the processed surface coexists with several forms of silicon (c-Si, a-Si, Si-XII), and the pit shows a crystalline state, while the metastable Si-XII and a-Si are generated at the wire mark, but there are three forms in the smoother place;
(4) The amorphous state mainly depends on the cutting wire speed and is also related to the diamond grain size. At low speed, the main performance is amorphous and poly-crystalline.