Method for improving flatness of silicon wafer after epitaxy

The invention relates to a method for improving the flatness of a silicon wafer after epitaxy, which belongs to the technical field of silicon wafer processing technology, and comprises the following operation steps of: 1, drawing a low-pollution and high-quality single crystal rod by selecting a high-purity polycrystalline material and a high-purity quartz crucible in a clean crystal drawing environment; and step 2, obtaining a crystal segment with a proper size through cutting and barreling, and then obtaining a linear cutting sheet with excellent flatness parameters such as Warp, Bow and TTV and no serious edge deformation by controlling the process stability of a linear cutting process, such as the stability of cutting out and cutting in. And thirdly, the cutting piece is polished to obtain a mirror polished piece, and the mirror polished piece comprises the steps of piece grinding, chamfering, corrosion, double-face polishing, single-face polishing, flatness measurement and final cleaning. The method has