Method for improving yield of semiconductor device

Abstract

The invention provides a method for improving the yield of a semiconductor device, which comprises the following steps: providing a substrate, and sequentially forming a dielectric layer, a floating gate layer and an interlayer dielectric layer on the substrate; forming a mask layer on the surface of the interlayer dielectric layer and the surface of a shallow trench isolation, wherein the substrate comprises a central area and an edge area, and the thickness of the mask layer in the edge area is larger than that of the mask layer in the center of the substrate and the central area; and sequentially etching the mask layer and part of the shallow trench isolation until the shallow trench isolation reaches a standard height. The method for improving the yield of the semiconductor device finally enables the height of the residual shallow trench isolation in the edge area of the substrate and the height of the residual shallow trench isolation in the central area of the substrate to reachthe standard, avoids the failure of the semiconductor device and improves the yield of the semiconductor device.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for improving the yield of semiconductor devices. Background technique [0002] In the current semiconductor industry, memory devices account for a considerable proportion of integrated circuit products. The development of flash memory in memory is particularly rapid. Its memory cell is based on the traditional MOS transistor structure, adding a floating gate (Floating Gate, FG) and a layer of tunnel oxide layer (Tunnel Oxide), and using the floating gate to store charges to achieve non-volatile storage. However, a Shallow Trench Isolation (STI, Shallow Trench Isolation) structure is required between memory cells for electrical isolation. [0003] The flash memory is divided into two types: a stackgate device and a splitgate device. The stackgate device has a floating gate and a control gate, and the control gate is located above the floating gate. In the sp...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for improving the yield rate of semiconductor devices, to solve the semiconductor problem caused by the height of the shallow trench isolation in the prior art being too high or too low when adjusting the height of the shallow trench isolation in the flash memory. The problem of device yield decline

Images