A process method for increasing ild filling window with adjustable control grid

Abstract

A process method for increasing an ILD filling window with an adjustable control gate, which includes: providing a base with a unit storage area and a peripheral device area; depositing a first polysilicon gate layer on the surface of the base; Grow a silicon oxide barrier layer; apply photoresist and develop on the surface of the silicon oxide barrier layer to expose the peripheral device area, and only etch and remove the silicon oxide barrier layer in the peripheral device area; the silicon oxide barrier layer in the cell storage area Deposit a second polysilicon gate layer on the surface of the first polysilicon gate layer in the peripheral device area; perform photoresist coating and development on the surface of the second polysilicon gate layer to expose the cell storage area, and etch to remove only the cell The second polysilicon gate layer in the storage area; etch to remove the remaining silicon oxide barrier layer; perform photoresist coating and development on the surface of the polysilicon gate in the unit storage area and peripheral device area, and dry etch to form the final Double polysilicon gate structure.

Description

technical field [0001] The invention relates to the field of integrated circuit manufacturing, in particular to a process method for increasing an ILD filling window with an adjustable control gate. Background technique [0002] A floating gate type non-volatile memory (Non-volatile memory, referred to as NVM) is a common integrated circuit device, which includes a source, a drain, a gate and a floating gate (Floating Gate). Generally, a floating-gate nonvolatile memory structure can be formed using a classic stack-gate process. The polysilicon layer close to the tunnel oxide layer is used as a floating gate, the top polysilicon layer is used as a control gate poly, and the insulating layer between the two polysilicon layers is a silicon dioxide or ONO (Oxide-Nitride-Oxide) structure. The effect of isolating the floating gate area. [0003] Compared with volatile memory, due to the existence of floating gate, non-volatile memory can still maintain data information even whe...

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Problems solved by technology

[0011] At present, the peripheral device area and the control gate of the unit storage area of ​​the floating gate nonvolatile memory can be deposited in one step by furnace tube technology, and the thickness is generally about 2000 angstroms, while the unit storage area of ​​the floating gate nonvolatile memory device In addition to the control gate with the same thickness as the peripheral device area, there is also a floating gate structure with a thickness of about 1000 angstroms. As the size of NVM continues to decrease, the aspect ratio of the space trench in the cell storage area increases greatly. , in the ILD (interlayer Deposition) process, it is very easy to generate voids (void), and it becomes very difficult to completely fill the trenches in the cell storage area, which will seriously affect the reliability of the device

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