JP2014053438A - Process of manufacturing magnetoresistive element - Google Patents
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 37
- 238000000034 method Methods 0.000 title abstract description 25
- 230000004888 barrier function Effects 0.000 claims abstract description 48
- 238000001020 plasma etching Methods 0.000 claims abstract description 6
- 230000005291 magnetic effect Effects 0.000 claims description 66
- 229910019236 CoFeB Inorganic materials 0.000 claims description 3
- 239000000696 magnetic material Substances 0.000 abstract description 7
- 230000000694 effects Effects 0.000 abstract description 5
- 230000015556 catabolic process Effects 0.000 abstract description 2
- 238000006731 degradation reaction Methods 0.000 abstract description 2
- 238000000151 deposition Methods 0.000 abstract 2
- 239000010410 layer Substances 0.000 description 58
- 229910052751 metal Inorganic materials 0.000 description 34
- 239000002184 metal Substances 0.000 description 34
- 238000005530 etching Methods 0.000 description 18
- 239000000463 material Substances 0.000 description 13
- 238000012545 processing Methods 0.000 description 13
- 239000011229 interlayer Substances 0.000 description 11
- 235000012431 wafers Nutrition 0.000 description 11
- 230000005294 ferromagnetic effect Effects 0.000 description 8
- 238000000137 annealing Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- 238000012864 cross contamination Methods 0.000 description 4
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 4
- 239000000395 magnesium oxide Substances 0.000 description 4
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 4
- 230000005415 magnetization Effects 0.000 description 4
- 238000000059 patterning Methods 0.000 description 4
- 229910052715 tantalum Inorganic materials 0.000 description 4
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 4
- 229910052581 Si3N4 Inorganic materials 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 3
- 238000001459 lithography Methods 0.000 description 3
- 238000002161 passivation Methods 0.000 description 3
- 230000007261 regionalization Effects 0.000 description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 3
- 238000004381 surface treatment Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910018936 CoPd Inorganic materials 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
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- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
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- 230000005381 magnetic domain Effects 0.000 description 1
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- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000007781 pre-processing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
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- Mram Or Spin Memory Techniques (AREA)
- Hall/Mr Elements (AREA)
Abstract
Description
本発明は、磁気抵抗素子の製造方法に関し、特に磁気抵抗メモリの製造方法に関する。 The present invention relates to a method for manufacturing a magnetoresistive element, and more particularly to a method for manufacturing a magnetoresistive memory.
次世代のメモリ素子としてスピントルク技術を利用したデバイスは、リフレッシュのための電気的なエネルギーを必要としない不揮発性、書き換えの高速動作、および書き込み寿命の点から近年注目されている。また、ロジックデバイスへの適用では、低リーク電流、配線遅延の回避が可能で、開発に拍車がかけられている。 In recent years, devices using spin torque technology as a next-generation memory element have attracted attention in terms of non-volatility that does not require electrical energy for refresh, high-speed rewrite operation, and write life. In addition, the application to logic devices can avoid low leakage current and wiring delay, which has spurred development.
磁気抵抗メモリ(Ｍａｇｎｅｔｏｒｅｓｉｓｔｉｖｅ Ｒａｎｄｏｍ Ａｃｃｅｓｓ Ｍｅｍｏｒｙ：以下、ＭＲＡＭと称する)や磁気ヘッドの製造工程では、強磁性体金属膜間に配置された障壁層の絶縁膜に流れるトンネル電流（磁気抵抗）の変化を信号として書き込んだり、読み取ったりすることによって、デバイスとしての役割を果たす。また、メモリ素子としてのオン/オフ時のトンネル磁気抵抗(Ｔｕｎｎｅｌ Ｍａｇｎｅｔｏ−Ｒｅｓｉｓｔａｎｃｅ：以下、ＴＭＲと称する)比等のデバイス特性は、強磁性体金属膜の結晶性、障壁層の絶縁膜の結晶性および酸化状態で左右されるため、強磁性体金属膜および障壁層の成膜や強磁性体金属膜および障壁層の成膜前後の取り扱い方にいろいろなノウハウがあり、特許文献１に開示されている。 In the manufacturing process of a magnetoresistive memory (hereinafter referred to as MRAM) and a magnetic head, a change in a tunnel current (magnetoresistance) flowing in an insulating film of a barrier layer disposed between ferromagnetic metal films is signaled. As a device by writing and reading as In addition, device characteristics such as a tunnel magnetoresistance (hereinafter referred to as TMR) ratio at the time of ON / OFF as a memory element include crystallinity of a ferromagnetic metal film and crystallinity of an insulating film of a barrier layer. Since it depends on the oxidation state, there are various know-hows in the formation of the ferromagnetic metal film and the barrier layer and the handling method before and after the formation of the ferromagnetic metal film and the barrier layer. Yes.
また、微細化に伴うパターンの合わせ方についても様々なノウハウがある。例えば、特許文献２に開示されたモールド材とスタンパを利用してパターンを形成する手段、特許文献３に開示された２回露光と呼ばれるリソグラフィー技術を用いた手段、特許文献４に開示された自己整合を意識した手段等がある。 There is also a variety of know-how on how to match patterns with miniaturization. For example, means for forming a pattern using a mold material and a stamper disclosed in Patent Document 2, means using a lithography technique called double exposure disclosed in Patent Document 3, and self disclosed in Patent Document 4 There are means that are conscious of consistency.
例えばＭＲＡＭの製造において、強磁性体金属膜をプラズマエッチングにより高精度にパターニングする加工は難しいが、更に障壁層の絶縁膜をプラズマエッチングにより高精度にパターニングする加工が困難である。なぜならば、この障壁層の膜厚は、1nm程度であり、ウェハ全面にわたって、同時に加工されるわけではないからである。 For example, in the manufacture of MRAM, it is difficult to pattern a ferromagnetic metal film with high precision by plasma etching, but it is also difficult to pattern the insulating film of the barrier layer with high precision by plasma etching. This is because the film thickness of this barrier layer is about 1 nm and is not processed simultaneously over the entire wafer surface.
例えば、特許文献１に記載されているような膜を、マスク材をもとに下地層まで一気にエッチングする場合、上層のウェハ内の各層の膜厚のバラツキや、エッチングの不均一性が蓄積されているため、障壁層の絶縁膜の加工のタイミングがウェハ面内で、ばらつく。つまり、障壁層の絶縁膜がエッチングされている箇所、障壁層の絶縁膜の上層の強磁性体膜までしかエッチングされていない箇所、または、障壁層の絶縁膜の下層の強磁性体膜がエッチングされている箇所がウェハ面内に発生する。 For example, when a film as described in Patent Document 1 is etched all at once to a base layer based on a mask material, variations in the thickness of each layer in the upper wafer and non-uniform etching are accumulated. Therefore, the processing timing of the insulating film of the barrier layer varies within the wafer surface. That is, a portion where the insulating film of the barrier layer is etched, a portion where only the upper ferromagnetic film of the barrier layer is etched, or a ferromagnetic film under the insulating film of the barrier layer is etched. The part where it is done occurs in the wafer surface.
このため、従来のプラズマエッチングによるパターニングにおいては、多層膜の材質の違いによるエッチング速度の比（選択性）を利用して、障壁層の手前でエッチング処理の進行合わせるようなことを実施していたが、ＭＲＡＭの高集積化に伴う高微細化のパターニングには従来技術による対応が困難になってきた。 For this reason, in the conventional patterning by plasma etching, the etching process is performed in front of the barrier layer by using the ratio (selectivity) of the etching rate depending on the material of the multilayer film. However, it has become difficult to respond to the patterning with high miniaturization accompanying the high integration of MRAM by the conventional technique.
更に、障壁層の絶縁膜側壁の加工面に、磁性体材料や電極の導伝性材料が付着すると、トンネル電流以外の電流の流路となったり、また寄生容量を生じさせたりしてデバイス特性を悪化させることがある。 In addition, if magnetic material or electrode conductive material adheres to the processed surface of the insulating film side wall of the barrier layer, it becomes a flow path for current other than tunnel current, and causes parasitic capacitance, resulting in device characteristics. May worsen.
このため、障壁層のエッチング処理前、または、障壁層のエッチング処理後に一旦エッチング処理を中断させて、エッチング形状の側壁のエッチングサイドウォールの除去工程、安定化工程、または、加工面を保護するための、例えばシリコンナイトライド膜(以下、ＳｉＮ膜と称する)によるパッシベーション膜の塗布が行われる。例えばパッシベーション膜の塗布を行った後は、更に下層までエッチング処理が継続される。しかし、このような従来技術でも有効な解決手段になり得ていない。 For this reason, the etching process is temporarily interrupted before the barrier layer etching process or after the barrier layer etching process, and the etching sidewall removal process, the stabilization process, or the processed surface is protected. For example, a passivation film is applied by a silicon nitride film (hereinafter referred to as a SiN film). For example, after the passivation film is applied, the etching process is continued to the lower layer. However, even such a conventional technique cannot be an effective solution.
また、最近この障壁層の絶縁膜として、酸化マグネシウム(ＭｇＯ)がその結晶性から注目されているが、この酸化マグネシウムは潮解性があり、一旦大気に取り出し、水分が侵入すると結晶性が損なわれる。このため、エッチング処理室と、表面改質チャンバー、もしくはパッシベーションを行う成膜チャンバーを真空中や窒素パージ雰囲気下で接続させて、その中でウェハのハンドリングを行うような処理装置のインライン化が試みられている。 Recently, magnesium oxide (MgO) has attracted attention as an insulating film for this barrier layer due to its crystallinity, but this magnesium oxide has deliquescence, and once it is taken out into the atmosphere and moisture enters, the crystallinity is impaired. . For this reason, in-line processing equipment that handles the wafer by connecting the etching chamber and the surface modification chamber or the film forming chamber for passivation in a vacuum or under a nitrogen purge atmosphere is attempted. It has been.
しかしながら、これらの強磁性体金属膜や障壁層の絶縁膜の処理を上記のように実施したとしても、ウェハ全面に良好なデバイス動作を得るには大きな問題がある。エッチング処理室では様々な反応生成物が存在してエッチング処理室の壁に付着しており、再脱離して処理前中のウェハに再入射してくる。 However, even if the processing of the ferromagnetic metal film and the insulating film of the barrier layer is performed as described above, there is a big problem in obtaining good device operation over the entire surface of the wafer. In the etching chamber, various reaction products exist and adhere to the walls of the etching chamber, re-detach and re-enter the wafer before processing.
また、量産における処理の再現性を得る上でもこの反応生成物等のデポ量の経時的な変化を回避することは容易なことではない。また、材料膜間のクロスコンタミネーションに対する加工方法への配慮が従来技術では十分であるとはいえない。更に、特にメモリ向けのデバイスでは、量産収益性の確保から、近々ウェハとして、４５０ｍｍの大口径ウェハが適用される予定であり、４５０ｍｍのウェハの処理では、磁性膜および障壁層の加工の均一性や、クロスコンタミネーションの回避が大きな課題になると想定される。 In addition, it is not easy to avoid a change in the amount of deposits of the reaction product over time in order to obtain reproducibility of processing in mass production. In addition, it cannot be said that the conventional technique is sufficient in consideration of the processing method for cross contamination between material films. Furthermore, in order to ensure mass production profitability, 450mm large-diameter wafers will soon be applied as wafers, especially for memory devices. In the processing of 450mm wafers, the processing uniformity of the magnetic film and barrier layer is expected. And avoiding cross-contamination is expected to be a major issue.
本発明は、これらの問題点に鑑みてなされたもので、ＭＲＡＭ等の磁気抵抗効果を利用した磁気抵抗素子の製造方法において、デバイス特性の劣化を許容範囲内に抑制できる磁気抵抗素子の製造方法を提供する。 The present invention has been made in view of these problems, and in a method of manufacturing a magnetoresistive element using a magnetoresistive effect such as MRAM, a method of manufacturing a magnetoresistive element that can suppress deterioration of device characteristics within an allowable range. I will provide a.
本発明は、磁気抵抗素子の製造方法において、第一の磁性体膜を成膜し、予めパターンニングされたマスクを用いて前記第一の磁性体膜をプラズマエッチングした後、前記プラズマエッチングされた第一の磁性体膜の上方に障壁層と、前記プラズマエッチングされた第一の磁性体膜との間に前記障壁層を挟む第二の磁性体膜と、を順次成膜することを特徴とする。 According to the present invention, in the method of manufacturing a magnetoresistive element, a first magnetic film is formed, the first magnetic film is plasma-etched using a pre-patterned mask, and then the plasma etching is performed. A barrier layer and a second magnetic film sandwiching the barrier layer between the plasma-etched first magnetic film are sequentially formed above the first magnetic film. To do.
本発明により、ＭＲＡＭ等の磁気抵抗効果を利用した磁気抵抗素子の製造方法において、デバイス特性の劣化を許容範囲内に抑制できる。 According to the present invention, in the method of manufacturing a magnetoresistive element using the magnetoresistive effect such as MRAM, it is possible to suppress degradation of device characteristics within an allowable range.
本発明は、ＭＲＡＭ等の磁気抵抗効果を利用した磁気抵抗素子の製造方法において、障壁層の上方に配置され障壁層と磁性体膜を含む第一の積層膜の成膜より前に、障壁層の下方に配置され磁性体膜を含む第二の積層膜にプラズマによりパターンを形成することを特徴とする磁気抵抗素子の製造方法である。 The present invention relates to a method of manufacturing a magnetoresistive element using a magnetoresistive effect such as an MRAM, and the barrier layer is disposed above the barrier layer and before the first laminated film including the barrier layer and the magnetic film is formed. A pattern is formed by plasma on a second laminated film including a magnetic film disposed below the magnetoresistive element.
さらに本発明は、前記第二の積層膜のパターン寸法より大きくなるように前記第一の積層膜のパターン寸法を形成する。 Furthermore, in the present invention, the pattern dimension of the first laminated film is formed so as to be larger than the pattern dimension of the second laminated film.
さらに本発明は、前記第二の積層膜のパターン形成後に層間絶縁膜で埋めて平坦化し、
ダメージ層の除去と回復を実施した後、前記第一の積層膜を成膜する。引き続き、前記第一の積層膜の成膜後にアニール等の表面処理を施して、表面処理を施された第一の積層膜にプラズマによりパターンを形成する。
Furthermore, the present invention is planarized by filling with an interlayer insulating film after pattern formation of the second laminated film,
After removing and recovering the damaged layer, the first laminated film is formed. Subsequently, a surface treatment such as annealing is performed after the first laminated film is formed, and a pattern is formed by plasma on the first laminated film subjected to the surface treatment.
以下、本発明の一実施例であるＭＲＡＭの製造方法について図面を用いて説明する。図１ないし図４は、ＭＲＡＭの製造方法を示した模式図であり、特に、ＤＲＡＭ(Ｄｙｎａｍｉｃ Ｒａｎｄｏｍ Ａｃｃｅｓｓ Ｍｅｍｏｒｙ)のキャパシタに相当する磁気トンネル接合(Ｍａｇｎｅｔｉｃ Ｔｕｎｎｅｌ Ｊｕｎｃｔｉｏｎ：以下、ＭＴＪと称する)の形成方法を示す。 A method for manufacturing an MRAM that is one embodiment of the present invention will be described below with reference to the drawings. 1 to 4 are schematic views showing a method of manufacturing an MRAM, and in particular, a method of forming a magnetic tunnel junction (hereinafter referred to as an MTJ) corresponding to a DRAM (Dynamic Random Access Memory) capacitor. Indicates.
先ず、図１(ａ)に示すように、予め形成されたスルーホールの配線０２を絶縁する絶縁膜０１の上に第一の金属膜１であるタンタル(Ｔａ)と、第二の金属膜２であるルテニウム(Ｒｕ)と、第三の金属膜３であるタンタル(Ｔａ)と、フリー層である第一の磁性体膜４のＣｏＦｅＢと、パターンを形成するためのマスクであるハードマスク材２１のシリコン窒化膜(ＳｉＮ)とがそれぞれ、順次積層される。 First, as shown in FIG. 1A, tantalum (Ta) as the first metal film 1 and the second metal film 2 are formed on the insulating film 01 that insulates the wirings 02 formed in advance. Ruthenium (Ru), third metal film 3 tantalum (Ta), first magnetic film 4 CoFeB as a free layer, and hard mask material 21 as a mask for forming a pattern These silicon nitride films (SiN) are sequentially stacked.
ここでの積層膜を第二の積層膜とする。また、ここで、フリー層とは、外部磁場やスピン注入により磁化の向きが反転可能な磁性層のことである。また、本実施例では、配線０２は、予め下層に形成されていることにしたが、本発明としては、必ずしも予め形成されている必要はない。 The laminated film here is a second laminated film. Here, the free layer is a magnetic layer whose magnetization direction can be reversed by an external magnetic field or spin injection. In the present embodiment, the wiring 02 is formed in the lower layer in advance. However, the present invention does not necessarily have to be formed in advance.
次に、図１(ｂ)に示すように、ハードマスク材２１の上に微細パターンを形成する工程であるＳＡＤＰ(Ｓｅｌｆ−ａｌｉｇｎｅｄ Ｄｏｕｂｌｅ Ｐａｔｔｅｒｎｉｎｇ)等のリソ技術を用いて、微細なマスク２２をパターニングする。尚、マスク２２のパターニングは、従来技術を用いて行ったため、本実施例での説明は、省略する。 Next, as shown in FIG. 1B, the fine mask 22 is patterned by using a lithography technique such as SADP (Self-aligned Double Patterning), which is a process of forming a fine pattern on the hard mask material 21. To do. Note that the patterning of the mask 22 is performed by using the conventional technique, and thus the description in this embodiment is omitted.
次に、図１(ｃ)に示すようにマスク２２のパターンを、ハードマスク材２１にエッチングにより転写する。 Next, as shown in FIG. 1C, the pattern of the mask 22 is transferred to the hard mask material 21 by etching.
続いて、図２(ｄ)に示すように、エッチングによりマスク２２のパターンが転写されたハードマスク２３をマスクとして第一の磁性体膜４から絶縁膜０１まで順次エッチングを行う。また、ハードマスク２３で第一の磁性体膜４から第三の金属膜３まで順次エッチングし、第二の金属膜２をストッパ膜としてハードマスク２３を除去した後に、ハードマスク２３と異なるマスクを形成し、第二の金属膜２や第一の金属膜１をエッチングしても良い。 Subsequently, as shown in FIG. 2D, etching is sequentially performed from the first magnetic film 4 to the insulating film 01 using the hard mask 23 to which the pattern of the mask 22 is transferred by etching as a mask. Further, the first magnetic film 4 to the third metal film 3 are sequentially etched with the hard mask 23, and after removing the hard mask 23 using the second metal film 2 as a stopper film, a mask different from the hard mask 23 is formed. Alternatively, the second metal film 2 and the first metal film 1 may be etched.
次に図２(ｅ)に示すように、層間絶縁膜２４を埋め込む。そして、図２(ｆ)に示すように層間絶縁膜２４をエッチバックまたは、ＣＭＰ(Ｃｈｅｍｉｃａｌ Ｍｅｃｈａｎｉｃａｌ Ｐｏｌｉｓｈｉｎｇ)により研磨し、さらにハードマスク２３を除去した後ＣＭＰにより研磨して第一の磁性体膜４の表面を露出させる。または、第一の磁性体膜４の表面上に層間絶縁膜２４がわずかに残るようにしてＣＭＰの研磨を終了しても良い。この場合は、次の成膜に先駆けて実施する前処理で、残りの層間絶縁膜２４を除去して第一の磁性体膜の表面を露出させる。 Next, as shown in FIG. 2E, an interlayer insulating film 24 is embedded. Then, as shown in FIG. 2F, the interlayer insulating film 24 is etched back or polished by CMP (Chemical Mechanical Polishing), the hard mask 23 is further removed, and then polished by CMP to be polished by the first magnetic film 4. To expose the surface. Alternatively, the CMP polishing may be completed so that the interlayer insulating film 24 remains slightly on the surface of the first magnetic film 4. In this case, the remaining interlayer insulating film 24 is removed and the surface of the first magnetic film is exposed by pre-processing performed prior to the next film formation.
次に必要であれば、エッチバックやＣＭＰでダメージを受けた層の除去、水素等での還元、またはアニーリング処理を行い、第一の磁性体膜４の表面の清浄化を実施する。 Next, if necessary, the surface of the first magnetic film 4 is cleaned by removing the layer damaged by etch back or CMP, reducing with hydrogen, or annealing.
次に図３(ｇ)に示すように、第一の磁性体膜４の上にトンネル電流が流れる障壁層１１のＭｇＯと、固定層である第二の磁性体膜１２のＣｏＦeＢと、第四の金属膜１３であるタンタル(Ｔａ)と、第一の積層された磁性体膜１４と、第五の金属膜１５であるＣｏＰdと、第二の積層された磁性体膜１６と、第六の金属膜１７であるＣｏＰｄと、第七の金属膜１８であるタンタル(Ｔａ)と、パターンを形成するためのマスクであるハードマスク材１９のシリコン窒化膜(ＳｉＮ)が順次積層される。 Next, as shown in FIG. 3G, MgO of the barrier layer 11 in which the tunnel current flows on the first magnetic film 4, CoFeB of the second magnetic film 12 as the fixed layer, and the fourth Tantalum (Ta), which is the metal film 13, the first laminated magnetic film 14, CoPd, which is the fifth metal film 15, the second laminated magnetic film 16, and the sixth CoPd as the metal film 17, tantalum (Ta) as the seventh metal film 18, and a silicon nitride film (SiN) as a hard mask material 19 as a mask for forming a pattern are sequentially stacked.
ここでの積層膜を第一の積層膜とする。また、ここで、固定層とは、外部磁場やスピン注入により磁化の向きが固定されたままの磁性層のことである。また、第一の積層された磁性体膜１４と第二の積層された磁性体膜１６は、第二の磁性体膜１２の磁化を安定させるために設けられたものであるため、本発明として必ずしも必要な積層膜ではない。 The laminated film here is referred to as a first laminated film. Here, the fixed layer is a magnetic layer whose magnetization direction is fixed by an external magnetic field or spin injection. In addition, the first laminated magnetic film 14 and the second laminated magnetic film 16 are provided to stabilize the magnetization of the second magnetic film 12. It is not necessarily a necessary laminated film.
次に図３(ｈ)に示すように、ＳＡＤＰ等のリソ技術を用いてマスク２５を形成する。また、マスク２５の形成方法は、マスク２２と同様なため、説明を省略する。また、マスク２５の形成の際には、エッチングされた第二の積層膜とのマスクの合せ精度が求められるため、磁場を利用してエッチングされた第一の磁性体膜４の磁化を利用した磁区観察要コロイド液、超微細トナー、および磁性流体微粒子を利用したマスクを形成しても良い。 Next, as shown in FIG. 3H, a mask 25 is formed using a lithography technique such as SADP. Further, the method of forming the mask 25 is the same as that of the mask 22, and thus the description thereof is omitted. Further, when the mask 25 is formed, since the mask alignment accuracy with the etched second laminated film is required, the magnetization of the first magnetic film 4 etched using a magnetic field is used. A mask using the magnetic domain observation colloid liquid, ultrafine toner, and magnetic fluid fine particles may be formed.
次に図３(ｉ)に示すように、マスク２５のパターンをハードマスク材１９に転写してハードマスク２６を形成し、ハードマスク２６をマスクとして第七の金属膜１８をエッチングする。この後、図４(ｊ)に示すように、第六の金属膜１７から障壁層１１まで順次エッチングする。 Next, as shown in FIG. 3I, the pattern of the mask 25 is transferred to the hard mask material 19 to form a hard mask 26, and the seventh metal film 18 is etched using the hard mask 26 as a mask. Thereafter, as shown in FIG. 4J, the sixth metal film 17 to the barrier layer 11 are sequentially etched.
本実施例では、ハードマスク２６だけで第七の金属膜１８から障壁層１１をエッチングする例であったが、ハードマスク２６をマスクとして第七の金属膜１８までエッチングし、第六の金属膜１７をストッパ膜としてハードマスク２６を除去して形成される第七の金属膜１８のメタルマスクを用いて障壁層１１までエッチングしても良い。 In the present embodiment, the barrier layer 11 is etched from the seventh metal film 18 using only the hard mask 26. However, the sixth metal film 18 is etched using the hard mask 26 as a mask to the seventh metal film 18. The barrier layer 11 may be etched using a metal mask of the seventh metal film 18 formed by removing the hard mask 26 using 17 as a stopper film.
さらに、本実施例での障壁層１１は、最後までエッチングされてマスクで覆われていない部分が完全に除去された例であったが、障壁層の一部が残っていても良いし、または、第二の積層膜の層間絶縁膜２４の一部までエッチングしても良い。 Furthermore, the barrier layer 11 in this example is an example in which the portion that has been etched to the end and is not covered with the mask is completely removed, but part of the barrier layer may remain, or Alternatively, a part of the interlayer insulating film 24 of the second laminated film may be etched.
次に図４(k)に示すように、層間絶縁膜２７を埋め込む。そして、図４(ｌ)に示すように層間絶縁膜２７をエッチバックまたは、ＣＭＰにより研磨し、さらにハードマスク１９を除去した後ＣＭＰにより研磨して第七の金属膜１８の表面を露出させる。 Next, as shown in FIG. 4K, an interlayer insulating film 27 is embedded. Then, as shown in FIG. 4L, the interlayer insulating film 27 is polished by etch back or CMP, and the hard mask 19 is removed and then polished by CMP to expose the surface of the seventh metal film 18.
障壁層１１と第一の磁性体膜４と第二の磁性体膜１２の結晶性を回復させるためのアニーリング処理については、図3(g)のように第一の積層膜の成膜が終わった段階、図４(ｌ)の第七の金属膜１８の表面を露出させた段階、または図４(ｌ)以降のＭＲＡＭの製造工程のいずれかで行われれば良い。尚、以上がＭＲＡＭのＭＴＪの形成に関する説明であったが、図４(ｌ)以降のアニーリング処理以外の製造工程は、従来技術と同じであるため、図４(ｌ)以降の製造工程の説明を省略する。 With respect to the annealing process for recovering the crystallinity of the barrier layer 11, the first magnetic film 4 and the second magnetic film 12, the first stacked film is formed as shown in FIG. This step may be performed at any one of the following steps, the step of exposing the surface of the seventh metal film 18 in FIG. 4L, or the manufacturing process of the MRAM in FIG. The above is the description regarding the formation of the MTJ of the MRAM. However, since the manufacturing process other than the annealing process after FIG. 4 (l) is the same as the prior art, the description of the manufacturing process after FIG. Is omitted.
障壁層１１に流れるトンネル電流の量は、第一の磁性体膜４と第二の磁性体膜１２のそれぞれの面積、結晶性、さらには、エッチング加工された端部の結晶性や汚染材料の侵入に大きく依存する。また、デバイスの特性、トンネル電流値は、主に第一の磁性体膜４の作る磁性流で決定されるため、例えば、垂直加工が可能なエッチングやリフトオフといった、その他の手法が可能であれば、意図的に第二の磁性体膜１２のパターン寸法が第一の磁性体膜４のパターン寸法より大きくなるように加工すると良い。 The amount of tunneling current that flows through the barrier layer 11 depends on the area and crystallinity of the first magnetic film 4 and the second magnetic film 12, as well as the crystallinity of the etched edge and contamination material. Rely heavily on intrusion. In addition, since the device characteristics and the tunnel current value are mainly determined by the magnetic current formed by the first magnetic film 4, other methods such as etching or lift-off capable of vertical processing are possible. It is preferable to intentionally process the pattern dimension of the second magnetic film 12 to be larger than the pattern dimension of the first magnetic film 4.
上述した本発明のデバイスの製造方法により、パターン形成の際に前記第一の積層膜に含まれる磁性体膜の側壁に付着した反応生成物によるデバイス特性に対する影響は回避できる。これは、トンネル電流が前記第二の積層膜に含まれる磁性体膜に接する磁気抵抗膜でほとんど決まるためである。 By the device manufacturing method of the present invention described above, it is possible to avoid the influence on the device characteristics due to the reaction product attached to the side wall of the magnetic film included in the first laminated film during pattern formation. This is because the tunnel current is almost determined by the magnetoresistive film in contact with the magnetic film included in the second laminated film.
また、本発明は、前記第一の積層膜の中で最後に障壁層１１にパターンを形成し、また、デバイス特性は、前記第一の積層膜に含まれる磁性体膜の加工精度ではなく、第二の積層膜に含まれる磁性体膜の加工精度により支配されるため、障壁層１１に至るまでのパターン形成の精度は、あまり必要としない。しかし、高精度にパターン形成できれば、障壁層１１へのパターン形成する際のマージンを確保できるので、障壁層１１に至るまでのパターン形成の精度は、高い方が望ましい。 Further, the present invention forms a pattern in the barrier layer 11 at the end of the first laminated film, and the device characteristics are not the processing accuracy of the magnetic film included in the first laminated film, Since it is governed by the processing accuracy of the magnetic film included in the second laminated film, the pattern forming accuracy up to the barrier layer 11 is not so necessary. However, if a pattern can be formed with high accuracy, a margin for forming a pattern on the barrier layer 11 can be secured. Therefore, it is desirable that the pattern formation accuracy up to the barrier layer 11 is high.
また、障壁層１１のエッチングで形成された側壁が他の材料の付着で汚染されていても、また多少結晶性が損なわれていても、本実施例のＭＲＡＭの製造方法であれば、デバイス特性に影響を与えにくい。このため、クロスコンタミネーションの影響が回避できる。 Even if the side wall formed by etching the barrier layer 11 is contaminated by the adhesion of other materials or the crystallinity is somewhat impaired, the device characteristics of the MRAM according to this embodiment can be obtained. It is hard to affect. For this reason, the influence of cross contamination can be avoided.
更に、本実施例での障壁層１１のエッチングでは、障壁層１１の下方は層間絶縁膜２４であるために、障壁層１１のオーバーエッチングを多少、過剰に行ってもデバイス特性に大きな影響を及ぼさない。 Further, in the etching of the barrier layer 11 in this embodiment, since the interlayer insulating film 24 is below the barrier layer 11, even if the barrier layer 11 is over-etched to some extent, the device characteristics are greatly affected. Absent.
本実施例の図４(ｌ)以降は、表面処理を施して、大気に取り出しても良い。厚さ1nm以下の縦方向でなく、数nmの横方向に存在するので、磁気水分等の侵入による結晶欠陥の耐性も向上する。もちろん、そのまま真空中や不活性ガス雰囲気中で運んで層間絶縁膜を成膜しても良い。 After FIG. 4 (l) of this embodiment, the surface treatment may be performed and taken out to the atmosphere. Since it exists not in the vertical direction with a thickness of 1 nm or less but in the horizontal direction of several nm, resistance to crystal defects due to penetration of magnetic moisture and the like is improved. Needless to say, the interlayer insulating film may be formed as it is in a vacuum or in an inert gas atmosphere.
このように、本実施例によれば、脆弱な膜である障壁層１１の加工の進行度合いや、端部の汚染に対するマージンも増大し、素子間のバラツキを低減できるので、磁気抵抗素子の製造に対する信頼性の確保と、歩留まり向上を図ることができる。 As described above, according to the present embodiment, the progress of processing of the barrier layer 11 which is a fragile film and the margin for contamination of the end portion can be increased, and variation between elements can be reduced. As a result, it is possible to ensure the reliability and improve the yield.
また、本実施例で説明に用いた、磁性体膜、障壁層、金属膜、ハードマスク材は一例であり、本発明はこれに限定されない。 Further, the magnetic film, the barrier layer, the metal film, and the hard mask material used for the description in this embodiment are examples, and the present invention is not limited to this.
また、本実施例では、第一の磁性体膜４をフリー層、第二の磁性体膜１２を固定層として説明したが、本発明としては、第一の磁性体膜４を固定層、第二の磁性体膜１２をフリー層としても本実施例と同等の効果を得ることができる。 In this embodiment, the first magnetic film 4 is described as a free layer and the second magnetic film 12 is defined as a fixed layer. However, in the present invention, the first magnetic film 4 is defined as a fixed layer, Even if the second magnetic film 12 is a free layer, the same effect as in this embodiment can be obtained.
さらに、本実施例では、ＭＲＡＭの製造方法について説明したが、ＴＭＲ応用デバイス、磁気ヘッド、ＳＴＴ−ＲＡＭ（Ｓｐｉｎ Ｔｏｒｑｕｅ Ｔｒａｎｓｆｅｒ−Ｒａｎｄｏｍ Ａｃｃｅｓｓ Ｍｅｍｏｒｙ）等の磁気抵抗素子の製造方法に適用できる。 Furthermore, although the manufacturing method of the MRAM has been described in the present embodiment, the present invention can be applied to a manufacturing method of a magnetoresistive element such as a TMR application device, a magnetic head, or an STT-RAM (Spin Torque Transfer-Random Access Memory).
以上、上述した通り、本発明により、ウェハ全面に渡り良品を取得することが容易となり、クロスコンタミネーションの抑制、エッチング不均一性に対する裕度が増大し、更に大気解放時の結晶欠陥回避が可能である。 As described above, according to the present invention, it is easy to obtain good products over the entire surface of the wafer, suppression of cross-contamination, an increased tolerance for etching non-uniformity, and further avoidance of crystal defects when released to the atmosphere. It is.
また、デバイス特性にクリティカルな障壁層の下方の磁性体膜の加工精度が、積層膜を少なくして加工できるため、個々の加工精度、経時的な変化に対しても変動を低く抑えことができ、生産性を低下させること無く、磁気抵抗素子の量産が可能となる。 In addition, since the processing accuracy of the magnetic film under the barrier layer critical to device characteristics can be processed with fewer stacked films, fluctuations can be suppressed even with respect to individual processing accuracy and changes over time. Thus, mass production of magnetoresistive elements can be performed without reducing productivity.
０１ 絶縁膜
０２ 配線
１ 第一の金属膜
２ 第二の金属膜
３ 第三の金属膜
４ 第一の磁性体膜
１１ 障壁層
１２ 第二の磁性体膜
１３ 第四の金属膜
１４ 第一の積層された磁性体膜
１５ 第五の金属膜
１６ 第二の積層された磁性体膜
１７ 第六の金属膜
１８ 第七の金属膜
１９、２１ ハードマスク材
２２、２５ マスク
２３、２６ ハードマスク
２４、２７ 層間絶縁膜
01 insulating film 02 wiring 1 first metal film 2 second metal film 3 third metal film 4 first magnetic film 11 barrier layer 12 second magnetic film 13 fourth metal film 14 first Laminated magnetic film 15 Fifth metal film 16 Second laminated magnetic film 17 Sixth metal film 18 Seventh metal film 19, 21 Hard mask material 22, 25 Mask 23, 26 Hard mask 24 27 Interlayer insulation film
Claims (5)
第一の磁性体膜を成膜し、
予めパターンニングされたマスクを用いて前記第一の磁性体膜をプラズマエッチングした後、前記プラズマエッチングされた第一の磁性体膜の上方に障壁層と、前記プラズマエッチングされた第一の磁性体膜との間に前記障壁層を挟む第二の磁性体膜と、を順次成膜することを特徴とする磁気抵抗素子の製造方法。 In the method of manufacturing a magnetoresistive element,
Forming a first magnetic film;
After plasma etching the first magnetic film using a pre-patterned mask, a barrier layer and the plasma-etched first magnetic body are formed above the plasma-etched first magnetic film. A method of manufacturing a magnetoresistive element, comprising: sequentially forming a second magnetic film sandwiching the barrier layer between the film and the film.
前記障壁層は、前記第二の磁性体膜の後にプラズマエッチングすることを特徴とする磁気抵抗素子の製造方法。 In the manufacturing method of the magnetoresistive element of Claim 1,
The method of manufacturing a magnetoresistive element, wherein the barrier layer is plasma-etched after the second magnetic film.
前記第二の磁性体膜の寸法は、前記第一の磁性体膜の寸法より大きくなるように加工されることを特徴とする磁気抵抗素子の製造方法。 In the manufacturing method of the magnetoresistive element of Claim 1,
The method of manufacturing a magnetoresistive element, wherein the dimension of the second magnetic film is processed to be larger than the dimension of the first magnetic film.
前記障壁層は、ＭｇＯであり、前記第一の磁性体膜および前記第二の磁性体膜は、ＣｏＦｅＢであることを特徴とする磁気抵抗素子の製造方法。 In the manufacturing method of the magnetoresistive element of Claim 1,
The method of manufacturing a magnetoresistive element, wherein the barrier layer is MgO, and the first magnetic film and the second magnetic film are CoFeB.
前記第一の磁性体膜は、フリー層であり、前記第二の磁性体膜は、固定層であることを特徴とする磁気抵抗素子の製造方法。 In the manufacturing method of the magnetoresistive element of Claim 4,
The method of manufacturing a magnetoresistive element, wherein the first magnetic film is a free layer, and the second magnetic film is a fixed layer.
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| WO2008120320A1 (en) * | 2007-03-28 | 2008-10-09 | Fujitsu Limited | Thin film magnetic head, method for fabricating the same and magnetic recorder |
| JP2009224477A (en) * | 2008-03-14 | 2009-10-01 | Fujitsu Ltd | Semiconductor storage device and method of manufacturing the same |
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| KR20160134587A (en) * | 2015-05-14 | 2016-11-23 | 삼성전자주식회사 | Multi-stage element removal using absorption layers |
| KR102557397B1 (en) * | 2015-05-14 | 2023-07-19 | 삼성전자주식회사 | Multi-stage element removal using absorption layers |
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