Manufacture method of floating gates

Abstract

The invention provides a manufacture method of floating gates. The manufacture method comprises the following steps that: a tunnel oxide layer and shallow trench isolation structures are formed on a semiconductor substrate, wherein each shallow trench isolation structure comprises a top structure and a main structure, and the side walls of the top structure are recessed towards the interior of the top structure, so that recessed parts can be formed; a floating gate polysilicon layer is formed on the tunnel oxide layer, wherein the floating gate polysilicon layer is provided with protruding parts which fill the recessed parts; at least a part of the top structure is removed through etching; ion injection is performed on the exposed protruding parts, so that a first ion injection layer can be formed on the protruding parts; oxidation treatment is performed on the first ion injection layer, so that a first oxide layer can be formed; and the first oxide layer is removed through etching, so that the floating gates can be formed. According to the manufacture method, the first ion injection layer is formed on the protruding parts, and the first oxide layer is formed on the first ion injection layer, and the structure of the first oxide layer is greatly different from the structure of the floating gate polysilicon layer, and the first oxide layer is removed through etching based on the structural difference of the first oxide layer and the floating gate polysilicon layer, and therefore, the irregular protruding parts can be modified, so that the regularly-shaped floating gates can be obtained.

Description

technical field [0001] The present application relates to the technical field of semiconductor manufacturing, and in particular, to a method for manufacturing a floating gate. Background technique [0002] Flash memory components have become a widely used device for personal computers and electronic devices due to their advantages of being able to store, read, and erase data multiple times, and the stored data will not disappear after power failure. non-volatile memory element. [0003] A typical flash memory device includes doped polysilicon to manufacture a floating gate (FloatingGate, FG) and a control gate (ControlGate, CG). like figure 2 As shown, the floating gate 104 is separated from the control gate by a stacked gate dielectric layer, and the floating gate 104 is separated from the semiconductor substrate 100 by a tunnel oxide layer 101 (TunnelOxide, TO), and the adjacent floating gate 104 The isolation is through a shallow trench isolation (STI) 102 provided in ...

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Problems solved by technology

Therefore, the existence of the protruding portion 131 in the floating gate 104 causes the floating gate 104 to be irregular in shape and the distance between adjacent floating gates 104 to become smaller, and the upper and lower distances of the irregularly shaped adjacent floating gates 104 are different, so that the floating gate 104 It is easy to generate mutual interference during use, so that the storage device has a potential risk of data loss

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