Preparation method of phase change memory electrode structure

Abstract

The invention relates to a preparation method of a phase change memory electrode structure. According to the method, firstly, a first insulation layer and a second insulation layer are sequentially deposited on a silicon substrate, then, a first round hole type groove penetrating through the first insulation layer and the second insulation layer is formed through etching; tungsten material is deposited in the first groove; then, the tungsten material filled in the first groove are etched by a dry etch back method until the upper surface of the tungsten material is aligned with the upper surface of the first insulation layer, a second round hole type groove is formed, and the tungsten material at the bottom of the second groove is used as a lower electrode; then, conducting thin film layers are deposited on the upper surface of the second insulation layer and the inner surface of the second groove, next, third insulation layer material is filled in the second groove, then, the redundant third insulation layer material and the conducting thin film layers on the upper surface of the second insulation layer are removed through chemical-mechanical polishing, and the rest conducting thin film layers are used as an upper electrode. The method has the characteristics that the qualification rate of devices is greatly improved, in addition, the height uniformity of annular electrodes in silicon wafers is improved, the resistance distribution is narrowed in the phase change process, and the stability of the devices is improved.

Description

technical field [0001] The invention relates to a method for preparing an electrode structure of a phase-change memory, belonging to the field of semiconductor devices. Background technique [0002] Phase-change memory technology is based on the idea that phase-change thin films can be applied to phase-change storage media proposed by Ovshinsky in the late 1960s and early 1970s. It is a storage device with low price and stable performance. Phase-change memory can be processed on silicon wafer substrates, and its key materials are recordable phase-change films, heating electrode materials, heat insulating materials, and top electrode materials. The basic principle of phase change memory is to use electric pulse signal to act on the device unit, so that the phase change material undergoes a reversible phase transition between the amorphous state and the polycrystalline state. By measuring the high resistance in the amorphous state and the polycrystalline state The low resista...

AI Technical Summary

Problems solved by technology

In the process of removing excess insulating dielectric and ring electrode by chemical mechanical polishing, due to the thickness of the ring electrode is very explosive, the signal of the end point detection is difficult to obtain, and it is difficult to use the end point detection method to control the polishing end point, which affects chemical mechanical polishing. There are many factors, such as polishing liquid, polishing pad, mechanical parameters (pressure, rotational speed, flow rate), etc., will have an impact on the polishing process, so the process of controlling the polishing end point by polishing time often leads to over-polishing or insufficient polishing, and over-polishing As a result, the height of the ring electrode will be shortened or even absent, and insufficient polishing will lead to an open circuit of the circuit, which will cause the failure of the device

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