Method for selectively etching magnetic tunnel junction double-layer hard mask by means of reactive ion beam
A magnetic tunnel junction and selective technology, applied in the field of reactive ion beam selective etching of magnetic tunnel junction double-layer hard masks, and hard mask etching, which can solve the problem of low SiN selectivity ratio, excessive consumption of Ta film, MTJ The pattern size becomes larger and other problems, so as to reduce the risk of short circuit and improve the effect of larger size
Active Publication Date: 2017-11-07
SHANGHAI CIYU INFORMATION TECH
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Problems solved by technology
[0007] In order to solve the above-mentioned technical problems, the present invention provides a method for selective etching of a magnetic tunnel junction (MTJ) double-layer hard mask by a reactive ion beam, which is especially 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 size of the MTJ pattern becomes larger when the double-layer mask is transferred, and the Ta film layer is excessively consumed in advance, which reduces the risk of MRAM circuit bit line and MTJ cell short circuit
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[0036] 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.
[0037] Such as image 3 Shown, a kind of reactive ion beam of the present invention selectively etches the method for magnetic tunnel junction (MTJ) double-layer hard mask, specifically comprises the following steps:
[0038]Step S1: providing a substrate 100 including an MTJ multilayer film, wherein the thickness of the MTJ is 15 nm˜40 nm.
[0039] Step S2: On the substrate, sequentially deposit and form a Ta film layer 101 and a SiN film layer (or SiO 2 film layer) 102, wherein the thickness of the ...
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The invention provides a method for selectively etching a magnetic tunnel junction double-layer hard mask by means of a reactive ion beam. The method comprises the steps of S1, supplying a substrate which comprises a magnetic tunnel junction multi-layer film; S2, successively forming a Ta film layer and an SiN film layer on the substrate; S3, performing patterned transferring of the magnetic tunnel junction pattern to the SiN film layer, and finishing patterned definition of the magnetic tunnel junction pattern by means of photoresist and an organic anti-reflection layer; S4, performing dry etching on the SiN film layer by means of CF4 for transferring the magnetic tunnel junction pattern to the Ta film layer; S5, eliminating the residual photoresist and the residual organic anti-reflection layer by means of oxygen dry etching, and S6, through using the SiN film as the mask, performing selective etching on the SiN film layer and the Ta film layer by means of CHF3 / N2. The SiN film layer can be replaced by the SiO2 film layer, and the step S6 can be replaced by performing selective etching on the SiO2 film layer and the Ta film layer by means of CHF3 / O2.
Description
technical field [0001] The invention relates to a method for etching a hard mask, in particular to a method for selectively etching a magnetic tunnel junction (MTJ, Magnetic Tunnel Junction) double-layer hard mask with a reactive ion beam, 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. consumption characteristics. 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 ma...
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Login to View More IPC IPC(8): H01L43/12C23F4/00
CPCC23F4/00H10N50/01
Inventor 张云森
Owner SHANGHAI CIYU INFORMATION TECH