Manufacturing method of floating gate and split gate flash memory

Abstract

The invention provides a method for manufacturing a floating gate and a split gate flash memory. The method includes establishing a sample: using a low-pressure chemical vapor deposition process to grow polysilicon on a wafer in a furnace tube, and performing ion implantation of the same dose on the polysilicon as a floating gate , collect the channel current values ​​at high level after the wafers at each position in the furnace tube form flash memory devices, and establish the sample channel current values ​​corresponding to each position of the wafer in the furnace tube; ion implantation dose allocation: in the furnace tube When the low-pressure chemical vapor deposition process is used to grow polysilicon floating gates on subsequent batches of wafers, the ion implantation doses of subsequent batches of wafers at each position in the furnace tube are adjusted according to the sample channel current values ​​at each position in the furnace tube, so that The floating gates grown at various positions in the furnace tube by subsequent batches of wafers have consistent and stable channel current values ​​when flash memory devices are formed. The invention can stabilize channel current and improve programming performance and erasing performance of split gate flash memory.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for manufacturing a floating gate and a split gate flash memory. Background technique [0002] In the manufacturing process of semiconductor devices, it is generally necessary to perform a thermal growth process on a wafer through a furnace tube to form a corresponding thin film layer. For non-volatile memories such as split-gate flash memory, floating gates (Floating Gate, FG) are often grown using polysilicon (Poly) in a furnace tube using a low-pressure chemical vapor deposition (LPCVD) process. Its furnace tube is a quartz tube, and multiple batches of wafers are processed simultaneously at multiple locations with the same dose of polysilicon. Due to the difference in the position of the furnace tube, the thermal budget (Thermo Budget) of different positions will be different, especially at the end of the furnace tube away from the gas source, due to the d...

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