Manufacturing method of phase change random access memory

Abstract

The invention provides a manufacturing method of a phase change random access memory. The manufacturing method comprises the following steps of: providing a semiconductor substrate, wherein a second insulating layer is formed on the semiconductor substrate, and is filled with a GST (Germanium-Stibium-Tellurium) phase change material; depositing a low-temperature oxide layer on the second insulating layer and the GST phase change material; patterning the low-temperature oxide layer to form a patterned low-temperature oxide layer covering the GST phase change material; depositing a silicon nitride layer and a third insulating layer in sequence on the second insulating layer and the patterned low-temperature oxide layer; etching the third insulating layer and the silicon nitride layer in sequence to fully expose the patterned low-temperature oxide layer and form an etching hole; removing the patterned low-temperature oxide layer in the etching hole; and forming a top electrode in the etching hole. In the invention, the low-temperature oxide layer and the silicon nitride layer serving as barrier layers are deposited in sequence, and an etching selection ratio between the low-temperature oxide layer and the GST phase change material is greater than 15 during wet etching, so that GST loss is avoided.

Description

technical field [0001] The invention relates to the technical field of semiconductor memory, in particular to a manufacturing method of a phase-change random access memory. Background technique [0002] Phase change random access memory (PCRAM) is a kind of memory that uses phase change thin film material as a storage medium to realize data storage. It is recognized as the most promising memory that can successfully break through the 22nm size node. [0003] Chalcogenide compound Ge composed of germanium (Ge)-antimony (Sb)-tellurium (Te) 2 Sb 2 Te 5 (GST), which can quickly achieve a reversible phase transition between crystalline and amorphous states, has become the most commonly used phase change material in PCRAM. GST is a low-resistance state in the crystalline state and a high-resistance state in the amorphous state, and the phase change memory uses the resistance difference when GST transitions between the crystalline state and the amorphous state to realize data st...

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Problems solved by technology

[0008] The purpose of the present invention is to provide a method for manufacturing phase-change random access memory to solve the extremely low etching between LTN and GST when the low-temperature nitride (LTN) barrier layer is removed by dry etching in the current upper electrode preparation process. The problem of loss of GST phase change material caused by selection ratio

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