Poly/OX selection ratio acquisition method based on semiconductor manufacturing

The invention discloses a Poly/OX selection ratio obtaining method based on semiconductor manufacturing. The Poly/OX selection ratio obtaining method comprises the steps that a wafer is arranged in a polycrystalline silicon etching machine table; etching gas containing fluorine type gas is introduced into the polycrystalline silicon etching machine table; performing ionization on the etching gas to obtain plasma required by etching; etching the polycrystalline silicon layer and the gate oxide layer on the wafer based on the plasma required by etching; plasma on the surface of the wafer is extracted, and etching of the polycrystalline silicon layer and the gate oxide layer is completed; and comparing the etching rates of the plasma on the polycrystalline silicon layer and the gate oxide layer under different gas flows to obtain different Poly/OX selection ratios. According to the method, the effect of improving the loss amount of the gate oxide layer under the polycrystalline silicon on the basis of ensuring t