A method for etching a magnetic tunnel junction double-layer conductive hard mask
A magnetic tunnel junction and hard mask technology, applied in the field of integrated circuit manufacturing, can solve problems such as low selection ratio, excessive consumption, and size change
Active Publication Date: 2020-07-07
SHANGHAI CIYU INFORMATION TECH CO LTD
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Problems solved by technology
[0007] The invention provides a magnetic tunnel junction (MTJ) double-layer conductive hard mask and an etching method thereof, which is particularly suitable for preparing MRAM circuits of 65nm and below, in order to solve the problem of Ta on SiN (or SiO 2 ) selection ratio is too low; the MTJ pattern changes in size when the double-layer mask is transferred; SiN (or SiO 2 ) film is thinner, the Ta film layer is excessively consumed in advance; in CH 3 Preparation of MTJ units under OH / Ar dry etching conditions, SiN (or SiO 2 ) film is thicker, as the sacrificial layer of SiN (or SiO 2 ) The selection ratio of MTJ is not high; it reduces the risk of MRAM circuit bit line and MTJ cell short circuit
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[0030] In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be noted that all the drawings of the present invention are in simplified form and use inaccurate scales, and are only used to facilitate and clearly assist the purpose of illustrating the embodiments of the present invention.
[0031] Such as image 3 As shown, a kind of magnetic tunnel junction (MTJ) double-layer conductive hard mask and etching method thereof provided by the present invention, specifically comprise the following steps:
[0032] Step S1: providing a substrate 100 including an MTJ multilayer film, wherein the thickness of the MTJ is 15 nm˜40 nm.
[0033] Step S2: On the substrate, sequentially deposit and form a Ta film layer 101 and a TiN film layer 102, wherein the thickness of the Ta film layer 101 is 50nm...
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Abstract
The invention provides a method for etching a magnetic tunnel junction double-layer conductive hard mask, comprising the following steps: S1. providing a substrate comprising a magnetic tunnel junction multilayer film; S2. sequentially forming a tantalum film layer and a tantalum film layer on the substrate Titanium nitride film layer; S3. Graphically transfer the magnetic tunnel junction pattern to the titanium nitride film layer, and use photoresist and organic anti-reflection layer to complete the pattern definition; S4. Use Cl 2 / CH 4 The mixed gas dry-etches the titanium nitride film layer to transfer the pattern to the Ta film layer; S5. Use HCl / He / O 2 Selective etching is performed on the titanium nitride film layer and the tantalum film layer to complete the patterning of the double-layer conductive hard mask; S6. Using an oxygen ashing process to remove excess photoresist and organic anti-reflection layer. It effectively solves the problems that the size of the magnetic tunnel junction pattern becomes larger when the double-layer mask is transferred, and the tantalum film layer is excessively consumed in advance, and reduces the risk of short circuit of the bit line of the MRAM circuit and the MTJ unit.
Description
technical field [0001] The invention relates to a magnetic tunnel junction (MTJ, Magnetic Tunnel Junction) hard mask, in particular to an etching method for a magnetic tunnel junction conductive double-layer hard mask, and belongs to the technical field of integrated circuit manufacturing. Background technique [0002] In recent years, Magnetic Random Access Memory (MRAM, Magnetic Radom Access Memory) using the magnetoresistance effect of Magnetic Tunnel Junction (MTJ) is considered to be the future solid-state non-volatile memory, which has high-speed reading and writing, large capacity and low energy consumption. specialty. 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...
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IPC IPC(8): H01L43/12H10N50/01
CPCH10N50/01
Inventor 张云森
Owner SHANGHAI CIYU INFORMATION TECH CO LTD