Manufacturing method of magnetic radom access memory unit array and peripheral circuit connecting wires

Abstract

The invention provides a manufacturing method of a magnetic radom access memory unit array and peripheral circuit connecting wires. The manufacturing method adopts a manner of manufacturing a bottom electrode contact layer on through holes of copper metal for covering copper through holes, and comprises the steps of: (1) providing a surface-polished CMOS substrate with the metal copper through holes, and making bottom electrode contact in the substrate; (2) manufacturing a magnetic tunnel junction structural unit on the bottom electrode contact; (3) and forming top electrode vias in the magnetic tunnel junction structural unit, and manufacturing metal connecting wires realizing connection with a logic / memory unit. since the bottom electrode contact material adopts non-copper metal, a magnetic tunnel junction can be manufactured on and its bottom electrodes can be formed in the surface-polished bottom electrode contact layer, thereby effectively preventing copper contamination and copper diffusion caused by directly manufacturing the MTJ on the copper Vx(x>=1) and the direct growth of an MTJ multilayer film on the coarse copper surface, and being very conductive to the optimizationand improvement of electrical performance of an MRAM loop and the miniaturization of the device.

Description

technical field [0001] The invention relates to a manufacturing method of a magnetic random access memory (MRAM) unit array and peripheral circuit wiring, and belongs to the technical field of magnetic random access memory (MRAM, Magnetic Radom Access Memory) manufacturing. Background technique [0002] In recent years, MRAM using magnetic tunnel junction (MTJ) has been considered as the future solid-state non-volatile memory, which has the characteristics of high-speed reading and writing, large capacity and low energy consumption. Ferromagnetic MTJ is usually a sandwich structure, which has a magnetic memory layer, which can change the magnetization direction to record different data; an insulating tunnel barrier layer in the middle; a magnetic reference layer, located on the other side of the tunnel barrier layer, which The direction of magnetization remains unchanged. [0003] In order to record information in this magnetoresistive element, it is suggested to use a writ...

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Problems solved by technology

However, since the size of the MTJ structural unit is smaller than that of the VIA x (x>=1) The size of the top opening is small. When etching the magnetic tunnel junction and its bottom electrode, in order to completely isolate the MTJ units, over-etching must be carried out. In the over-etching, the magnetic tunnel junction is not blocked. and its bottom electrode covered copper VIA x (x>=1) area will be partially etched and also damage its diffusion barrier layer (Ta / TaN), which will form copper VIA x (x>=1) to the diffusion channel of the low-k dielectric outside it, Cu atom will be diffused in the low-k dielectric, and this is bound to affect the electrical performance of MRAM, such as: time-dependent dielectric breakdown (TDDB , TimeDependent Dielectric Breakdown) and electron mobility (EM, Electron Mobility), etc., causing damage

[0006] In addition, during the over-etching process of the magnetic tunnel junction and its bottom electrode, due to ion bombardment (IonBombardment), copper atoms and their forming compounds will be sputtered to the sidewall of the magnetic tunnel junction and the etched low-k material surface, causing contamination and electrical shorts to the entire MRAM device

[0007] Another point is very critical. Since the copper surface is usually relatively rough, if the magnetic tunnel junction is directly grown on the copper, it will definitely affect the magnetoelectric properties of the MTJ multilayer film, resulting in a decrease in the magnetoresistance value.

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