Protection layer making method capable of avoiding projection generation

Abstract

The invention provides a manufacturing method of a protective layer which is capable of avoiding bump generation. The protective layer is made on a top-layer metal of a semiconductor device, the top-layer metal has a plurality of adjacent metal wires; and the protective layer comprises an oxide layer, a silicon nitride layer and a plastic protective layer. In the prior art, an enclosed space is formed among the adjacent metal wires with small spacing when the deposition of the oxide layer is completed, and part of gas is sealed, bumps are formed in the part of the gas in the subsequent steps,and the bumps affect reliability of the plastic protective layer and the semiconductor device. The manufacturing method of the protective layer comprises the following steps: firstly, depositing the oxide layer; etching the oxide layer to increase the spacing among the metal wires; then depositing the silicon nitride layer; and finally, coating and predrying the plastic protective layer. The protective layer without the bumps can be made by the manufacturing method of the protective layer which is capable of avoiding the bump generation, thus greatly improving the reliability of the semiconductor device.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for manufacturing a protective layer that can avoid protrusions. Background technique [0002] When fabricating storage devices such as dynamic random access memory (DRAM) and fast cycle random access memory (FCRAM), after the top layer of metal is fabricated, a protective layer for protecting the storage device needs to be fabricated on the top layer of metal, which includes a oxide layer, a silicon nitride layer, and a plastic protective layer (usually a polyimide film), wherein the plastic protective layer can effectively prevent the soft failure (softfailure) caused by α ions and can be used in the encapsulation of subsequent devices. play a buffer role. When making the protective layer, an oxide layer is first deposited by a low-pressure chemical vapor deposition process (LPCVD); then a silicon nitride layer is deposited by a plasma-enhanced chemical vapo...

AI Technical Summary

Problems solved by technology

[0003] There are multiple adjacent metal wires on the above-mentioned top layer metal, and the distance between the metal wires is getting smaller and smaller as the minimum feature size continues to decrease. When the oxide layer is deposited by the LPCVD process, it will be deposited on the edge of two adjacent metal wires Protruding shoulders, when the distance between two adjacent metal wires is small to a certain extent, the two opposite shoulders will be connected to form a closed space between two adjacent metal wires and a part of the air will be enclosed in the closed space , so the subsequently deposited silicon nitride and the coated plastic protective layer cannot enter the closed space. When the plastic protective layer is coated and pre-baked, the gas enclosed in the closed space will expand and move to the metal The ends of the wires (which can be observed by optical microscopy) form protrusions, which will affect the protective effect of the plastic protective layer and the reliability of the storage device

Images