Method of manufacturing phase-change memory

Abstract

The invention relates to a method of manufacturing a phase-change memory. The method includes the following steps that: a structure is formed, wherein the structure comprises bottom electrodes, a dielectric layer on the bottom electrode, an isolation layer which is arranged on the dielectric layer and has openings passing through the isolation layer, and a polysilicon layer which is arranged in the openings; first holes and second holes are formed, wherein the first holes and second holes respectively pass through the polysilicon layer and the dielectric layer, and the second holes are locatedbelow the first holes; a protective layer is formed in the first holes and the second holes and above the polysilicon layer; a chemical mechanical polishing process, or a dry etching process and a chemical mechanical polishing process are performed, so as to remove part of the protective layer, the isolation layer and the polysilicon layer, expose the dielectric layer, and preserve the protectivelayer in the second holes; the protective layer in the second holes is removed so as to expose the second holes; and a heating material is deposited into the second holes. With the method adopted, danger caused by using a tetramethylammonium hydroxide solution can be avoided, and hole damage in the dielectric layer can be avoided, and therefore, the holes have good dimensional stability.

Description

technical field [0001] The present disclosure is related to a method of fabricating a phase change memory. Background technique [0002] Electronic products such as cell phones, tablet computers, and digital cameras often have memory elements that store data. Conventional memory devices can store information through storage nodes on memory cells. Among them, the phase change memory utilizes the resistance state (eg high resistance value and low resistance value) of the memory element to store information. A memory device may have a material that is switchable between different phases (eg, crystalline and amorphous). The different phase states cause the memory cells to have resistance states of different resistance values ​​for representing different values ​​of stored data. [0003] The current process for fabricating phase change memory devices includes a typical keyhole transfer method. In detail, this method firstly forms a polysilicon layer with a keyhole structure (...

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Problems solved by technology

[0004] However, in the step of removing the remaining polysilicon layer, a solution with a very high selectivity to the polysilicon layer and surrounding materials, such as tetramethylammonium hydroxide (TMAH) solution, is usually used for wet etching to avoid Damage the hole, which will lead to a change in the size of the hole and affect the performance of the phase change memory

However, tetramethylammonium hydroxide solution is highly toxic and highly lethal, causing great danger to operators

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