Study On The Subsurface Microcrack Detection Of Single Crystal Silicon Wafer By Grinding

Monocrystalline silicon wafer is the most widely used substrate material in the manufacturing process of integrated circuits.The surface integrity of the silicon wafer material directly affects the performance,yield and service life of the device.However,the single crystal silicon wafer inevitably produces a subsurface damage layer of a few microns to tens of microns during the grinding process,which will directly affect its subsequent processing efficiency and removal amount.The subsurface damage layer must be removed in the subsequent processing,which undoubtedly increases the manufacturing cost of the silicon wafer and reduces the manufacturing efficiency.Therefore,in order to remove the sub-surface damage layer produced by grinding and improve efficiency,it is of great guiding significance for the subsequent processing to quickly and accurately obtain the micro-crack information in the sub-surface damage layer produced by the grinding process.In this paper,#400 and #600 cup-shaped diamond wheels are used to grind single-crystal silicon wafers.Combined with the advantages of destructive detection and non-destructive detection,a variety of detection methods are used to detect the subsurface microcracks of the silicon wafer.The main research contents of this article are as follows:(1)Based on the quasi-static indentation fracture model,considering the superposition of the elastic stress field and the residual stress field,a mathematical model between the surface roughness of the silicon wafer grinding and the depth of the subsurface microcrack was established.By detecting the PV value of the surface roughness at different positions to determine the degree of damage to the silicon wafer at the corresponding location.(2)The cross-sectional microscopic detection method and the stepped etching method were used to detect the subsurface microcracks of the silicon wafer from different directions.The distribution of the subsurface microcrack inclination angle,the distribution of the subsurface microcrack depth along the grinding marks and the subsurface microcrack density were analyzed.Thus,the three-dimensional distribution information of subsurface microcracks is obtained.(3)The non-destructive detection of the subsurface microcracks of the single crystal silicon wafer is carried out by the polarized laser scattering detection method,and the corresponding detection signal strength is obtained,and then the subsurface damage information is quantitatively determined by the destructive detection method,thereby establishing the relationship between the detection signal strength and the subsurface microcrack volume,and finally carry out verification tests to prove its reliability.