JP2018004654A - Magnetostriction measuring device and magnetostriction measurement method - Google Patents
Magnetostriction measuring device and magnetostriction measurement method Download PDFInfo
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本開示は、ウエハなどの板体に形成された磁性体を適切に歪ませる磁歪計測のための応力印加機構及びそれを用いた磁歪計測装置、磁歪計測方法に関する。 The present disclosure relates to a stress application mechanism for magnetostriction measurement for appropriately distorting a magnetic body formed on a plate such as a wafer, a magnetostriction measurement apparatus using the stress application mechanism, and a magnetostriction measurement method.
磁性体には、Ni-FeやFe-Siなどの軟磁性材料と、Fe-Nd-B、Sm-Coなどの硬質磁性材料とがあり、産業の基盤材料の役割を担っている。磁性体の磁歪と材料の機械的歪みが共存すると、磁気弾性効果を通して磁気異方性の乱れが生じ、本来あるべき磁気特性に望ましくない変化を与える。機械的歪みは、材料の形態（薄膜であるか、バルクであるか）に関係なく、ほとんど全ての加工プロセスにおいて発生するものである。それゆえ、磁歪の計測は、品質管理のうえで重要である。 Magnetic materials include soft magnetic materials such as Ni-Fe and Fe-Si, and hard magnetic materials such as Fe-Nd-B and Sm-Co, and play the role of industrial base materials. When the magnetostriction of the magnetic material and the mechanical strain of the material coexist, the magnetic anisotropy is disturbed through the magnetoelastic effect, and an undesirable change is given to the magnetic characteristics that should originally exist. Mechanical strain occurs in almost all processing processes regardless of the material morphology (thin film or bulk). Therefore, the measurement of magnetostriction is important for quality control.
従来の磁歪計測法は、磁性体に磁場を印加し、磁化方向の変化に伴う磁歪、すなわち磁性体の伸び縮みを測定し、磁歪定数λを算出する方法（本明細書では、磁場印加法と表記する）が提案されている。具体的に、バルク材料であれば、その伸び縮みを電気容量の変化として検出し、磁歪定数λを算出する装置が一般的である。薄膜であれば、薄膜及び薄膜が形成された基板の複合的な反りを、表面に照射したレーザ光の反射方向の変化として検出し、磁歪定数λを算出する。 A conventional magnetostriction measurement method is a method of applying a magnetic field to a magnetic material, measuring magnetostriction accompanying a change in magnetization direction, that is, measuring the expansion and contraction of the magnetic material, and calculating a magnetostriction constant λ (in this specification, the magnetic field application method and Has been proposed). Specifically, in the case of a bulk material, an apparatus that detects the expansion / contraction as a change in electric capacity and calculates the magnetostriction constant λ is common. In the case of a thin film, the composite warp of the thin film and the substrate on which the thin film is formed is detected as a change in the reflection direction of the laser light irradiated on the surface, and the magnetostriction constant λ is calculated.
一方、材料に既知の歪みを加えて、その時の磁気特性の変化から歪みに起因する磁気異方性を推定し、磁歪定数λを求める方法（本明細書では、歪み印可法と表記する）が提案されている。この方法は、上記従来法に比べて高感度であり、強い磁場を必要としないので軟磁性、硬質磁性を問わず応用できる点で優れたアイディアである。 On the other hand, by adding a known strain to the material, estimating the magnetic anisotropy due to the strain from the change in magnetic properties at that time, and obtaining the magnetostriction constant λ (in this specification, referred to as strain application method) Proposed. This method is excellent in that it can be applied to both soft magnetism and hard magnetism because it is more sensitive than the conventional method and does not require a strong magnetic field.
しかしながら、上記歪み印加法では、歪みを均一で定量的に印加する方法が未だ提案されておらず、さらに、機械的に歪みを付与する必要があるため、歪み印加用の治具のサイズ低下が困難であり、このような治具を高感度透磁率計、試料振動型磁力計、Ｂ−Ｈトレーサー、などに装着するには、利便性に劣り、実用的ではない。 However, in the strain application method, a method for applying the strain uniformly and quantitatively has not been proposed yet, and further, since it is necessary to mechanically apply strain, the size of the strain application jig is reduced. It is difficult to mount such a jig on a high-sensitivity magnetic permeability meter, sample vibration type magnetometer, BH tracer, etc., and it is not practical.
そのためか、上記磁場印加法が採用されるのが一般的である。しかし、最近では、磁性体を使う磁気デバイスも薄膜化し、Ｓｉウエハ上に高密度に集積して作成される。このウエハ上の磁性薄膜の磁歪を測定するには、ウエハから測定用サンプルを切り出す必要があるので、破壊検査となり、また、生産ライン上での管理ができないので、生産管理が煩雑である。 For this reason, the magnetic field application method is generally adopted. However, recently, a magnetic device using a magnetic material is also made thin and integrated on a Si wafer with a high density. In order to measure the magnetostriction of the magnetic thin film on the wafer, it is necessary to cut out a measurement sample from the wafer, which is a destructive inspection and cannot be managed on the production line, so that production management is complicated.
本開示は、このような未知の課題に着目してなされたものであって、その目的は、単純な構造でコンパクトでき且つ均一な歪みを印加可能な応力印加機構を提供するとともに、非破壊且つ生産ライン上に適用できる有用な磁歪計測装置、磁歪計測方法を提供することである。 The present disclosure has been made by paying attention to such an unknown problem. The object of the present disclosure is to provide a stress application mechanism that can be compact with a simple structure and that can apply a uniform strain. It is an object of the present invention to provide a useful magnetostriction measuring apparatus and magnetostriction measuring method applicable to a production line.
本開示は、上記目的を達成するために、次のような手段を講じている。 In order to achieve the above object, the present disclosure takes the following measures.
本開示の応力印加機構は、磁性体を有する板体を保持するための本体と、前記本体と前記板体との間に気密空間を形成するための環状のシール部材と、前記板体を前記シール部材へ押圧するための押え機構と、前記気密空間に流体を出し入れするための導通路と、を有し、前記導通路を介した前記気密空間への流体の加圧又は減圧によって、前記磁性体及び前記板体に対して歪みを付与可能に構成されている。 The stress applying mechanism of the present disclosure includes a main body for holding a plate body having a magnetic body, an annular seal member for forming an airtight space between the main body and the plate body, and the plate body A presser mechanism for pressing against the seal member, and a conduction path for taking fluid into and out of the airtight space, and pressurizing or depressurizing the fluid to the airtight space via the conduction path It is comprised so that a distortion | strain can be provided with respect to a body and the said board.
このように、ウエハなどの板体と本体との間に環状のシール部材によって気密空間を形成し、この気密空間に流体の加圧又は減圧によって板体に歪みを与えるので、板体及び磁性体に均一な歪みを付与可能となる。それでいて、シール部材と流体を用いるだけなので、複雑な機械的機構を設けずにすみ、小型化が可能となる。 Thus, an airtight space is formed by an annular sealing member between a plate body such as a wafer and the main body, and the plate body and the magnetic body are distorted by pressurizing or depressurizing fluid in the airtight space. A uniform strain can be imparted to the surface. Nevertheless, since only the seal member and the fluid are used, it is not necessary to provide a complicated mechanical mechanism, and the size can be reduced.
以下、本開示の応力印加機構及び磁歪計測装置について、図面を参照して説明する。 Hereinafter, the stress application mechanism and the magnetostriction measurement device of the present disclosure will be described with reference to the drawings.
［応力印加機構］
図２に示すように、応力印加機構１は、磁性体を有する板体Ｗを保持し、磁性体の磁歪を計測するために用いられる。本実施形態では、板体Ｗは、磁性体の薄膜を形成したウエハＷを例として説明するが、磁性体自体を板状に形成したものでもよい。応力印加機構１は、偏平形状の本体１０と、本体１０とウエハＷとの間に気密空間ＳＰを形成するための環状シール部材１１と、板体Ｗをシール部材１１へ押圧するための押え機構１２と、気密空間ＳＰに流体を出し入れするための導通路１３と、を有する。
[Stress application mechanism]
As shown in FIG. 2, the stress applying mechanism 1 is used to hold a plate body W having a magnetic body and measure the magnetostriction of the magnetic body. In the present embodiment, the plate W is described as an example of the wafer W on which a thin film of magnetic material is formed, but the magnetic material itself may be formed in a plate shape. The stress applying mechanism 1 includes a flat main body 10, an annular seal member 11 for forming an airtight space SP between the main body 10 and the wafer W, and a pressing mechanism for pressing the plate body W against the seal member 11. 12 and a conduction path 13 for taking fluid into and out of the airtight space SP.
本体１０は、正面視円盤状に形成されており、正面視中央部にウエハWが配置される。本体１０の中央部には、正面視で環状シール部材１１が配置されている。本実施形態では、シール部材１１はＯリングであり、正面視で円形に配置されているが、環内側に気密空間ＳＰを形成できれば、材質、正面視の形状は限定されない。シール部材１１の正面視の配置形状は、閉ループが形成されていれば、円形の他に、矩形状、多角形状などが挙げられる。環状シール部材１１は、ウエハＷの端部に沿って配置されている。本体１０、シール部材１１及び押え機構１２によってウエハＷの端部が把持される。 The main body 10 is formed in a disc shape when viewed from the front, and the wafer W is disposed at the center when viewed from the front. An annular seal member 11 is disposed at the center of the main body 10 when viewed from the front. In the present embodiment, the seal member 11 is an O-ring and is arranged in a circle when viewed from the front. However, the material and the shape when viewed from the front are not limited as long as the airtight space SP can be formed inside the ring. As long as the closed shape is formed, the arrangement shape of the sealing member 11 in a front view includes a rectangular shape and a polygonal shape in addition to a circular shape. The annular seal member 11 is disposed along the end of the wafer W. The end of the wafer W is gripped by the main body 10, the seal member 11, and the pressing mechanism 12.
押え機構１２は、押え部材１２ａと、第２の環状シール部材１２ｂと、を有する。押え部材１２ａは、正面視でリング状に形成されており、ウエハＷの中央部を正面側に開放する開放窓１２ｈが形成されている。第２の環状シール部材１２ｂは、上記環状シール部材１１と対をなしてウエハＷを挟む。押え部材１２ａは、その周縁部の複数箇所で本体１０に固定可能に構成されている。押え部材１２ａは、周縁部の複数箇所に長穴１２ｃを有する。長穴１２ｃは、本体１０に設けられたボルトｖｏが通る大きさの挿通領域と、ボルトｖｏの軸のみが通りボルト頭に干渉する大きさの干渉領域と、を有する。このため、押え部材１２ａを周方向にスライド動作させるだけで押え部材１２ａを本体１０に着脱可能となる。 The presser mechanism 12 includes a presser member 12a and a second annular seal member 12b. The pressing member 12a is formed in a ring shape when viewed from the front, and an opening window 12h that opens the central portion of the wafer W to the front side is formed. The second annular seal member 12b is paired with the annular seal member 11 and sandwiches the wafer W therebetween. The pressing member 12a is configured to be fixable to the main body 10 at a plurality of peripheral portions. The pressing member 12a has long holes 12c at a plurality of locations on the peripheral edge. The long hole 12c has an insertion region of a size through which the bolt vo provided in the main body 10 passes, and an interference region of a size through which only the axis of the bolt vo passes and interferes with the bolt head. For this reason, the presser member 12a can be attached to and detached from the main body 10 only by sliding the presser member 12a in the circumferential direction.
本実施形態では、押え機構１２は、第２の環状シール部材１２ｂを有するが、これを設けなくてもよい。図３に示すように、押え部材１２ａにシール部材１１に対応する突起１２ｄを設けてウエハＷを直接押えるようにしてもよい。また、押え部材１２ａは、リング状に形成され、周方向に連結しているが、押え部材１２ａを複数設けて、周方向の複数箇所でウエハＷを保持するようにしてもよい。 In the present embodiment, the presser mechanism 12 includes the second annular seal member 12b, but this need not be provided. As shown in FIG. 3, a protrusion 12d corresponding to the seal member 11 may be provided on the holding member 12a to directly hold the wafer W. Further, although the pressing member 12a is formed in a ring shape and connected in the circumferential direction, a plurality of pressing members 12a may be provided to hold the wafers W at a plurality of locations in the circumferential direction.
図２に示すように、導通路１３は、チャック本体１０内を通っている。本実施形態では、正面視で本体１０の周端部から中央部にある気密空間ＳＰに向けて面方向に沿って延びている。これにより、本体１０の正面側及び裏面側を有効利用可能にしている。また、本体１０は、環状シール部材１１の内周側に凹部１０ａを有し、凹部１０ａは導通路１３に連通している。勿論、本体１０の裏面から表面側に導通路１３を板厚方向に延びるように形成してもよい。その場合、凹部１０ａは設けなくてもよいが、凹部１０ａは、気密空間ＳＰであると共にウエハＷの反り代としても機能する。 As shown in FIG. 2, the conduction path 13 passes through the chuck body 10. In this embodiment, it extends along the surface direction toward the airtight space SP in the center part from the peripheral edge part of the main body 10 by front view. Thereby, the front side and the back side of the main body 10 can be effectively used. The main body 10 has a recess 10 a on the inner peripheral side of the annular seal member 11, and the recess 10 a communicates with the conduction path 13. Of course, the conduction path 13 may be formed so as to extend in the thickness direction from the back surface of the main body 10 to the front surface side. In this case, the concave portion 10a may not be provided, but the concave portion 10a functions as a warp allowance for the wafer W as well as the airtight space SP.
図１に示すように、対をなすシール部材１１，１２ｂでウエハＷを挟み込み、本体１０及び押え機構１２によってウエハＷを把持した状態において、導通路１３を介して気密空間ＳＰへ流体を入れて加圧すると、気密空間ＳＰの圧力が外部環境の気圧よりも高くなり、その結果、ウエハＷの把持点を支点としてウエハＷが実線で示すように正面側へ凸状に反る。一方、把持状態において、導通路１３を介して気密空間ＳＰから流体を抜き減圧すると、気密空間ＳＰの圧力が外部環境の気圧よりも低くなり、その結果、ウエハＷの把持点を支点としてウエハＷが二点鎖線で示すように裏面側へ凹状に反る。したがって、導通路１３を介した気密空間ＳＰへの流体の加圧又は減圧によって、磁性体及びウエハＷに対して歪みを付与可能となる。流体を用いているので、気密空間ＳＰに接触する部位全体に均一に歪みを与えることが可能となる。 As shown in FIG. 1, in a state where the wafer W is sandwiched between the pair of seal members 11 and 12 b and is gripped by the main body 10 and the pressing mechanism 12, a fluid is introduced into the airtight space SP via the conduction path 13. When pressurized, the pressure in the hermetic space SP becomes higher than the atmospheric pressure in the external environment, and as a result, the wafer W warps in a convex shape toward the front side as indicated by the solid line with the gripping point of the wafer W as a fulcrum. On the other hand, when the fluid is extracted from the hermetic space SP through the conduction path 13 and depressurized in the gripping state, the pressure in the hermetic space SP becomes lower than the atmospheric pressure in the external environment. As a result, the wafer W is supported with the gripping point of the wafer W as a fulcrum. As shown by a two-dot chain line, it warps in a concave shape toward the back surface side. Accordingly, it is possible to apply strain to the magnetic body and the wafer W by pressurizing or depressurizing the fluid to the hermetic space SP via the conduction path 13. Since the fluid is used, it becomes possible to uniformly strain the entire portion that contacts the airtight space SP.
流体としては、気体及び液体のいずれでもよいが、ウエハＷへの付着を考慮すれば、気体の方が好ましい。気体としては、空気、窒素、アルゴンなどの不活性ガスが挙げられる。液体としては、水、油が挙げられる。 The fluid may be either a gas or a liquid, but considering the adhesion to the wafer W, a gas is preferable. Examples of the gas include inert gases such as air, nitrogen, and argon. Examples of the liquid include water and oil.
本実施形態では、本体１０は正面視で円形であるが、これに限定されない。例えば、矩形形状などでもよい。また、本実施形態では、シール部材１１が正面視円状に配置されており、ウエハＷの支点が円状になるので、ウエハWが歪む領域が円形になり、他の形状に比べて、均一な歪みを印加することができる。また、矩形形状でシールできない場合、たとえば小さな短冊状の試料は、ダミーウエハに貼付けダミーウエハごと歪みを印加することができる。 In the present embodiment, the main body 10 is circular in front view, but is not limited thereto. For example, a rectangular shape or the like may be used. Further, in the present embodiment, the seal member 11 is arranged in a circular shape when viewed from the front, and the fulcrum of the wafer W is circular, so that the region in which the wafer W is distorted is circular and uniform compared to other shapes. Can be applied. Further, when the rectangular shape cannot be sealed, for example, a small strip-shaped sample can be applied to the dummy wafer by applying a strain to the dummy wafer.
［磁歪計測装置、方法］
磁歪計測装置は、歪み印可法により磁性体の磁歪を計測する装置である。磁歪計測装置は、上記応力印加機構１と、応力印加機構１の気密空間ＳＰの圧力を制御する圧力制御機構２、板体の磁性体の磁気共鳴周波数を測定する周波数測定部３と、気密空間ＳＰの圧力に応じた磁性体の歪量と周波数測定部３で測定した磁気共鳴周波数とに基づき磁歪値を算出する磁歪値算出部４と、を有する。
[Magnetostriction measuring apparatus and method]
The magnetostriction measuring device is a device that measures the magnetostriction of a magnetic material by a strain application method. The magnetostriction measuring apparatus includes the stress applying mechanism 1, a pressure control mechanism 2 that controls the pressure of the airtight space SP of the stress applying mechanism 1, a frequency measuring unit 3 that measures the magnetic resonance frequency of the magnetic material of the plate, and an airtight space. A magnetostriction value calculation unit 4 that calculates a magnetostriction value based on the amount of strain of the magnetic material according to the pressure of SP and the magnetic resonance frequency measured by the frequency measurement unit 3;
圧力制御機構２は、応力印加機構１の導通路１３を介して気密空間ＳＰの圧力を検出する圧力センサ２０と、応力印加機構１の導通路１３に対して流体を加圧又は減圧する流体駆動部２１と、圧力センサ２０が検出した圧力値に基づき、気密空間ＳＰの圧力が所定値になるように流体駆動部２１を制御する流体駆動制御部２２と、を有する。流体駆動部２１は、減圧及び加圧するポンプ、レギュレータ、バッファタンク、電磁弁、電磁弁制御回路、及びポンプ制御回路を有する。 The pressure control mechanism 2 includes a pressure sensor 20 that detects the pressure in the airtight space SP via the conduction path 13 of the stress application mechanism 1 and a fluid drive that pressurizes or depressurizes the fluid with respect to the conduction path 13 of the stress application mechanism 1. And a fluid drive control unit 22 that controls the fluid drive unit 21 so that the pressure in the hermetic space SP becomes a predetermined value based on the pressure value detected by the pressure sensor 20. The fluid drive unit 21 includes a pump that performs decompression and pressurization, a regulator, a buffer tank, a solenoid valve, a solenoid valve control circuit, and a pump control circuit.
周波数測定部３は、プローブ３０と、ネットワークアナライザ３１と、磁気共鳴周波数特定部３２と、を有し、プローブ３０により直流磁界を印加しキャリブレーションを行い、ネットワークアナライザ３１で各周波数での透過係数（Ｓ２１）を計測し、磁気共鳴周波数特定部３２が透過係数の周波数変化のうちピークを識別して、磁気共鳴周波数を特定する。周波数測定部３は既知であるので詳細を省略する。 The frequency measuring unit 3 includes a probe 30, a network analyzer 31, and a magnetic resonance frequency specifying unit 32. The probe 30 applies a DC magnetic field to perform calibration, and the network analyzer 31 transmits a transmission coefficient at each frequency. (S21) is measured, and the magnetic resonance frequency specifying unit 32 identifies the peak of the frequency change of the transmission coefficient, and specifies the magnetic resonance frequency. Since the frequency measuring unit 3 is known, the details are omitted.
磁歪値算出部４は、歪みを印加していないときの磁気共鳴周波数（ｆｒ０）と、伸び方向に所定量の歪み（＋σｆ）を与えたときの磁気共鳴周波数（ｆｒ＋）と、縮み方向に前記所定量と同じ量の歪み（−σｆ）を与えたときの磁気共鳴周波数（ｆｒ−）と、に基づき下記式（１）を用いて磁歪値（λｓ）を算出する。
λｓ＝｛８πＭｓ２・ｒ・ｈｆ・Δｆｒ｝／｛ｆｒ０・Ｅｓ・ｈｓ２｝ …（１）
Δｆｒは磁気共鳴周波数の変化量（ｆｒ＋ − ｆｒ−）である。
は、歪みが伸びのときの磁気共鳴周波数
Ｍｓは飽和磁化（１０４／４π）である。
Ｅｓは板体（例えばＳｉウエハＷ）のヤング率である。
ｈｓは板体（例えばＳｉウエハＷ）の厚みである。
ｒは歪んだ状態の基板中心の半径である。
ｈｆは磁性体の膜厚である。
The magnetostriction value calculation unit 4 reduces the magnetic resonance frequency (fr 0 ) when no strain is applied, the magnetic resonance frequency (fr + ) when a predetermined amount of strain (+ σ f ) is applied in the extension direction, and the contraction. The magnetostriction value (λs) is calculated using the following equation (1) based on the magnetic resonance frequency (fr − ) when the same amount of strain (−σ f ) is applied in the direction.
λs = {8πMs 2 · r · hf · Δfr} / {fr 0 · Es · hs 2 } (1)
Δfr is the amount of change (fr + −fr − ) in the magnetic resonance frequency.
The magnetic resonance frequency Ms when the strain is extended is the saturation magnetization (10 4 / 4π).
Es is the Young's modulus of the plate (for example, Si wafer W).
hs is the thickness of the plate (for example, Si wafer W).
r is the radius of the substrate center in a distorted state.
hf is the film thickness of the magnetic material.
磁気共鳴周波数以外のパラメータは、図示しない操作部を介して予め記憶されていることが好ましい。歪み量（基板中心の半径ｒ）について、気密空間を所定圧力にしたときの歪み量（半径ｒ）が既知である場合には、圧力制御機構によって上記所定圧力に制御することを条件として、歪み量（半径ｒ）を予め記憶されていることが好ましい。新規のウエハＷを用いた場合など、圧力と歪み量（半径ｒ）の関係が未知の場合には、図１にて点線で示すように、ウエハＷの歪み量（半径ｒ）を計測するためにレーザ変位計などの歪量検出部５を設けることが挙げられる。歪量検出部５は任意で設けることができる。 Parameters other than the magnetic resonance frequency are preferably stored in advance via an operation unit (not shown). With regard to the strain amount (radius r at the center of the substrate), if the strain amount (radius r) when the airtight space is set to a predetermined pressure is known, the strain is controlled on the condition that the pressure control mechanism controls the predetermined pressure. The amount (radius r) is preferably stored in advance. When the relationship between pressure and strain (radius r) is unknown, such as when a new wafer W is used, the strain (radius r) of the wafer W is measured as shown by the dotted line in FIG. It is possible to provide a strain amount detector 5 such as a laser displacement meter. The distortion amount detection unit 5 can be arbitrarily provided.
上記以外に、ウエハＷに外部磁界を印加する磁界印加部、応力印加機構１をＸ軸及びＹ軸に移動させる移動機構を設けてもよい。 In addition to the above, a magnetic field application unit that applies an external magnetic field to the wafer W and a movement mechanism that moves the stress application mechanism 1 in the X axis and the Y axis may be provided.
式（１）は、下記のように導出できる。
歪みがないときの磁気共鳴周波数ｆｒ０は、式（２）で表される。
薄膜材料の磁気異方性磁界＋外部磁界（100 Oe）は、次の式（３）で表される。
歪みが伸び方向のときの磁気共鳴周波数ｆｒ＋は、式（４）で表される。
歪みが縮み方向のときの磁気共鳴周波数ｆｒ−は、式（５）で表される。
磁気共鳴周波数の変化量は、式（６）で表される。
式（６）を変形すると式（１）が導出できる。
Equation (1) can be derived as follows.
The magnetic resonance frequency fr 0 when there is no distortion is expressed by equation (2).
The magnetic anisotropic magnetic field + external magnetic field (100 Oe) of the thin film material is expressed by the following formula (3).
The magnetic resonance frequency fr + when the strain is in the extension direction is expressed by Equation (4).
The magnetic resonance frequency fr − when the strain is in the shrinking direction is expressed by the equation (5).
The amount of change in the magnetic resonance frequency is expressed by Equation (6).
By transforming equation (6), equation (1) can be derived.
［測定例］
Si（シリコン）ウエハWに、磁性体を薄膜として形成し、上記装置を用いて磁歪を測定した。
試料薄膜は、Co90Zr10 , Ms = 104/4π= 796 emu/cm3 、ｆｒ０ = 5.75x109 Hzで、膜厚（ｈｆ）は、0.4μｍである。
ウエハWの基板厚み（ｈｓ）は150μｍ、ヤング率（Es）は1012dyn/cm2である。
図４Ａのように気密空間に圧力を加えて薄膜を延ばし、半径ｒを３０ｃｍにした状態で計測した結果を図５Ａに示す。磁気共鳴周波数の変化量は約130MHzであった。
図４Ｂのように気密空間を減圧して薄膜を縮め、半径ｒを３０ｃｍにした状態で計測した結果を図５Ｂに示す。磁気共鳴周波数の変化量は約60MHzであった。
Δｆｒ＝１３０＋６０＝１９０ｘ１０６Hzとなる。
これを式（１）に代入すれば、λｓ＝２．８×１０−６ となる。
試料薄膜（Co90Zr10）の磁歪定数（光反射法により測定）３×１０−６に一致する。
[Measurement example]
A magnetic material was formed as a thin film on a Si (silicon) wafer W, and magnetostriction was measured using the above apparatus.
The sample thin film has Co 90 Zr 10 , Ms = 10 4 / 4π = 796 emu / cm 3 , fr 0 = 5.75 × 10 9 Hz, and the film thickness (hf) is 0.4 μm.
The substrate thickness (hs) of the wafer W is 150 μm, and the Young's modulus (Es) is 10 12 dyn / cm 2 .
As shown in FIG. 4A, FIG. 5A shows the measurement result obtained by applying pressure to the airtight space to extend the thin film and setting the radius r to 30 cm. The amount of change in magnetic resonance frequency was about 130 MHz.
FIG. 5B shows the results of measurement in a state where the hermetic space is reduced in pressure as shown in FIG. 4B to shrink the thin film and the radius r is 30 cm. The amount of change in magnetic resonance frequency was about 60 MHz.
Δfr = 130 + 60 = 190 × 10 6 Hz.
Substituting this into equation (1) gives λs = 2.8 × 10 −6 .
The magnetostriction constant (measured by the light reflection method) of the sample thin film (Co 90 Zr 10 ) is 3 × 10 −6 .
磁歪の評価について、使用したネットワークアナライザ（型番５２２７Ａ）のカタログによれば周波数制度（Ｆｒｅｑｕｅｎｃｙ Ａｃｃｕｒａｃｙ）は±１ｐｐｍであった。これを周波数に換算すると約６ＧＨｚで周波数精度は６ｋＨｚとなる。よって２．９×１０−６の歪みに対して１９０ＭＨｚ周波数シフトしたから、歪の測定精度（理論値）は約１０−１０と得られた。これは既存の評価方法に比較して高感度な手法である。さらに強磁性共鳴周波数の推移についてはＣｏＮｂＺｒ薄膜を用いた実験で１ｎｍ厚みまでの評価できていることから、光学的手法では評価困難な極薄膜における磁歪評価にも本手法は適用可能である。 Regarding the evaluation of magnetostriction, according to the catalog of the network analyzer used (model number 5227A), the frequency system (Frequency Accuracy) was ± 1 ppm. When this is converted into frequency, the frequency accuracy is 6 kHz at about 6 GHz. Therefore, since the frequency was shifted by 190 MHz with respect to the distortion of 2.9 × 10 −6 , the measurement accuracy (theoretical value) of the distortion was about 10 −10 . This is a highly sensitive method compared to existing evaluation methods. Further, since the transition of the ferromagnetic resonance frequency can be evaluated up to 1 nm thickness by an experiment using a CoNbZr thin film, this method can be applied to magnetostriction evaluation in an ultrathin film that is difficult to evaluate by an optical method.
以上のように、本実施形態の応力印加機構１は、磁性体を有する板体Ｗを保持するための本体１０と、本体１０と板体Ｗとの間に気密空間ＳＰを形成するための環状のシール部材１１と、板体Ｗをシール部材１１へ押圧するための押え機構１２と、気密空間ＳＰに流体を出し入れするための導通路１３と、を有し、導通路１３を介した気密空間ＳＰへの流体の加圧又は減圧によって、磁性体及び板体Ｗに対して歪みを付与可能に構成されている。 As described above, the stress application mechanism 1 according to the present embodiment includes the main body 10 for holding the plate body W having a magnetic body and the annular shape for forming the airtight space SP between the main body 10 and the plate body W. The sealing member 11, the pressing mechanism 12 for pressing the plate body W against the sealing member 11, and the conduction path 13 for taking fluid into and out of the airtight space SP, and the airtight space via the conduction path 13 It is configured to be able to impart strain to the magnetic body and the plate body W by pressurizing or depressurizing the fluid to the SP.
このように、ウエハなどの板体Ｗと本体１０との間に環状のシール部材１１によって気密空間ＳＰを形成し、この気密空間ＳＰに流体の加圧又は減圧によって板体Ｗに歪みを与えるので、板体Ｗ及び磁性体に均一な歪みを付与可能となる。それでいて、シール部材と流体を用いるだけなので、複雑な機械的機構を設けずにすみ、小型化が可能となる。 As described above, the airtight space SP is formed by the annular seal member 11 between the plate body W such as a wafer and the main body 10, and the plate body W is distorted by pressurizing or depressurizing the fluid in the airtight space SP. Further, it becomes possible to apply a uniform strain to the plate body W and the magnetic body. Nevertheless, since only the seal member and the fluid are used, it is not necessary to provide a complicated mechanical mechanism, and the size can be reduced.
本実施形態において、本体１０は、正面視偏平形状であり、導通路１３は、正面視で周縁部から正面視中央部に延びている。この構成によれば、正面側及び裏面側に、導通路１３を構成する部材を配置しなくてよいので、正面側及び裏面側を有効利用可能となる。 In the present embodiment, the main body 10 has a flat shape when viewed from the front, and the conduction path 13 extends from the peripheral portion to the center when viewed from the front when viewed from the front. According to this structure, since the member which comprises the conduction path 13 does not need to be arrange | positioned in the front side and back surface side, the front side and back surface side can be used effectively.
本実施形態において、押え機構１２は、正面視リング状の押え部材１２ａと、環状のシール部材１１と対をなして板体Ｗを挟む第２の環状シール部材１２ｂと、を有する。この構成によれば、板体Ｗを正面及び裏面の両側からシール部材１１，１２ｂで保持するので、加圧及び減圧によって正面側及び裏面側の両方に板体を変形させる場合でも、適切な保持が可能となる。 In the present embodiment, the presser mechanism 12 includes a ring-shaped presser member 12a in front view and a second annular seal member 12b that forms a pair with the annular seal member 11 and sandwiches the plate body W therebetween. According to this configuration, the plate body W is held by the sealing members 11 and 12b from both the front and back sides, so that even when the plate body is deformed to both the front side and the back side by pressurization and decompression, the plate body W is appropriately held. Is possible.
本実施形態の磁歪計測装置は、上記応力印加機構１と、気密空間ＳＰの圧力を制御する圧力制御機構２と、磁性体の磁気共鳴周波数を測定する周波数測定部３と、気密空間ＳＰの圧力に応じた磁性体の歪量と周波数測定部３で測定した磁気共鳴周波数とに基づき磁歪値を算出する磁歪値算出部４と、を備える。 The magnetostriction measurement apparatus of the present embodiment includes the stress application mechanism 1, a pressure control mechanism 2 that controls the pressure of the hermetic space SP, a frequency measurement unit 3 that measures the magnetic resonance frequency of the magnetic material, and the pressure of the hermetic space SP. And a magnetostriction value calculation unit 4 that calculates a magnetostriction value based on the amount of distortion of the magnetic material according to the frequency and the magnetic resonance frequency measured by the frequency measurement unit 3.
この構成によれば、ウエハなどの板体W上の磁性体に均一な歪みを与え、磁気共鳴周波数を測定することで磁歪値を計測することが可能となる。それでいて、従来の磁場中での試料の伸縮を計測する方法では、試料に十分な厚みが必要であり、材料から試料を切り出して測定しなければならなかったが、本装置によれば、薄くなるほど歪みが増えるといった歪みを与える試料の厚みに制限がないこと、さらに、試料を破壊せずにプローブの位置によって局所的に計測できる。よって、非破壊且つ生産ライン上に適用できる計測装置を提供できる。 According to this configuration, it is possible to measure the magnetostriction value by applying a uniform distortion to the magnetic body on the plate body W such as a wafer and measuring the magnetic resonance frequency. Nevertheless, in the conventional method for measuring the expansion and contraction of a sample in a magnetic field, the sample needs to have a sufficient thickness, and the sample had to be cut out from the material and measured. There is no limit to the thickness of the sample that gives distortion, such as an increase in strain, and it can be measured locally by the position of the probe without destroying the sample. Therefore, it is possible to provide a measuring device that can be applied nondestructively on a production line.
本実施形態では、磁歪計測装置は、応力印加機構１に保持されている磁性体の歪量を計測する歪量検出部５を備える。この構成によれば、気密空間ＳＰの圧力と歪量の関係が未知の板体であっても、歪量を計測することにより、磁歪値を測定可能となる。 In the present embodiment, the magnetostriction measurement apparatus includes a strain amount detection unit 5 that measures the strain amount of the magnetic material held by the stress application mechanism 1. According to this configuration, even if the relationship between the pressure in the hermetic space SP and the strain amount is unknown, the magnetostriction value can be measured by measuring the strain amount.
本実施形態の磁歪計測方法は、上記応力印加機構１を用い、磁性体を有する基板Ｗを保持する応力印加機構１の気密空間ＳＰへ加圧し、基板Ｗを凸状に所定量歪ませた状態で磁性体の磁気共鳴周波数を計測すること、
応力印加機構１の気密空間ＳＰを減圧し、基板Ｗを凹状に前記所定量歪ませた状態で磁性体の磁気共鳴周波数を計測すること、
２つの状態の磁気共鳴周波数の変化量及び歪量に基づき磁歪値を算出すること、を含む。
In the magnetostriction measurement method of the present embodiment, the stress applying mechanism 1 is used to pressurize the hermetic space SP of the stress applying mechanism 1 holding the substrate W having a magnetic material, and the substrate W is distorted by a predetermined amount in a convex shape. Measuring the magnetic resonance frequency of a magnetic material with
Depressurizing the hermetic space SP of the stress applying mechanism 1 and measuring the magnetic resonance frequency of the magnetic material in a state where the substrate W is distorted into the concave shape by the predetermined amount;
Calculating a magnetostriction value based on the amount of change in magnetic resonance frequency and the amount of strain in two states.
この方法によって、上記磁歪計測装置と同じ作用効果を奏することができ、有用である。 By this method, the same effect as the magnetostriction measuring apparatus can be obtained and useful.
以上、本発明の実施形態について図面に基づいて説明したが、具体的な構成は、これらの実施形態に限定されるものでないと考えられるべきである。本発明の範囲は、上記した実施形態の説明だけではなく特許請求の範囲によって示され、さらに特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれる。 As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not only by the above description of the embodiments but also by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.
上記実施形態では、流体を用いて板体に応力を印加する圧力印加機構１を用いているが、圧力を印加する他の手段として、例えば図１のｘ方向またはｙ方向（互いに直交する第１方向及び第２方向のうちいずれか一方向）にのみ一定のｒを持つ形状を有する専用治具を設け、この専用治具に板体を貼り付けることで、均一な歪を印加することができる。 In the above-described embodiment, the pressure application mechanism 1 that applies stress to the plate body using a fluid is used. However, as another means for applying pressure, for example, the x direction or the y direction in FIG. Uniform strain can be applied by providing a dedicated jig having a shape having a constant r only in any one of the direction and the second direction and attaching a plate to the dedicated jig. .
上記治具を用いる場合、磁歪計測装置は、次のように構成できる。すなわち、磁歪計測装置は、互いに直交する第１方向及び第２方向のうちいずれか一方向にのみ一定のｒをもつ形状をなす治具と、前記治具に貼り付けられた板体の磁性体の磁気共鳴周波数を測定する周波数測定部３と、前記ｒの大きさに応じた磁性体の歪量と周波数測定部３で測定した磁気共鳴周波数とに基づき磁歪値を算出する磁歪値算出部４と、を有する。 When the jig is used, the magnetostriction measuring apparatus can be configured as follows. That is, the magnetostriction measuring apparatus includes a jig having a shape having a constant r only in any one of a first direction and a second direction orthogonal to each other, and a plate-like magnetic body attached to the jig. A frequency measurement unit 3 that measures the magnetic resonance frequency of the magnetic material, and a magnetostriction value calculation unit 4 that calculates a magnetostriction value based on the amount of distortion of the magnetic material corresponding to the magnitude of r and the magnetic resonance frequency measured by the frequency measurement unit 3. And having.
さらに、磁歪計測装置は、前記治具に貼り付けられている磁性体の歪量を計測する歪量検出部５を備えてもよい。この構成によれば、一定のｒを持つ形状に加工した治具上で板体のｒに誤差が生じた場合であっても、歪量を計測することにより、磁歪値を測定可能となる。 Furthermore, the magnetostriction measurement apparatus may include a strain amount detection unit 5 that measures the strain amount of the magnetic material attached to the jig. According to this configuration, even if an error occurs in r of the plate on a jig processed into a shape having a constant r, the magnetostriction value can be measured by measuring the strain amount.
磁歪計測方法は、磁性体を有する基板を、一定のｒを有する形状の治具に貼付け、基板Ｗを凸状に所定量歪ませた状態で磁性体の磁気共鳴周波数を計測すること、
前記治具を用いて、基板Ｗを凹状に前記所定量歪ませた状態で磁性体の磁気共鳴周波数を計測すること、
２つの状態の磁気共鳴周波数の変化量及び歪量に基づき磁歪値を算出すること、を含む。ここでいう所定量は、治具のｒの大きさに応じた量である。
The magnetostriction measurement method is a method in which a substrate having a magnetic material is attached to a jig having a constant r, and the magnetic resonance frequency of the magnetic material is measured in a state where the substrate W is distorted by a predetermined amount.
Using the jig, measuring the magnetic resonance frequency of the magnetic material in a state where the substrate W is distorted into the concave shape by the predetermined amount;
Calculating a magnetostriction value based on the amount of change in magnetic resonance frequency and the amount of strain in two states. The predetermined amount here is an amount corresponding to the size of r of the jig.
上記の各実施形態で採用している構造を他の任意の実施形態に採用することは可能である。各部の具体的な構成は、上述した実施形態のみに限定されるものではなく、本発明の趣旨を逸脱しない範囲で種々変形が可能である。 The structure employed in each of the above embodiments can be employed in any other embodiment. The specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
W…板体（ウエハ）
ＳＰ…気密空間
１０…本体
１１…シール部材
１２…押え機構
１２ａ…押え部材
１２ｂ…第２の環状シール部材
１３…導通路
２…圧力制御機構
３…周波数測定部
４…磁歪値算出部
５…歪量検出部
W ... Plate (wafer)
SP ... Airtight space 10 ... Main body 11 ... Sealing member 12 ... Pressing mechanism 12a ... Pressing member 12b ... Second annular sealing member 13 ... Conducting path 2 ... Pressure control mechanism 3 ... Frequency measuring unit 4 ... Magnetic strain value calculating unit 5 ... Strain Quantity detector
Claims (3)
前記治具を用いて、基板Ｗを凹状に前記所定量歪ませた状態で磁性体の磁気共鳴周波数を計測すること、
２つの状態の磁気共鳴周波数の変化量及び歪量に基づき磁歪値を算出すること、を含む、磁歪計測方法。 Affixing a substrate having a magnetic body to a jig having a constant r, and measuring the magnetic resonance frequency of the magnetic body in a state where the substrate W is distorted by a predetermined amount in a convex shape;
Using the jig, measuring the magnetic resonance frequency of the magnetic material in a state where the substrate W is distorted into the concave shape by the predetermined amount;
A magnetostriction measurement method including calculating a magnetostriction value based on a change amount and a strain amount of a magnetic resonance frequency in two states.
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| JP2011129798A (en) * | 2009-12-21 | 2011-06-30 | Mitsumi Electric Co Ltd | Magnetic material for high frequency application, high-frequency device, and magnetic grain |
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