JP2019140410A - Single crystal member formed with internal processed layer and method for manufacturing the same - Google Patents
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Abstract
Description
本発明は、シリコンの単結晶部材の被照射側の表面から単結晶部材内部にレーザ光を集光することで、単結晶部材内部に加工層を形成した内部加工層形成単結晶部材およびその製造方法に関する。 The present invention relates to an internally processed layer-forming single crystal member in which a processed layer is formed inside a single crystal member by condensing laser light from the surface on the irradiated side of the single crystal member of silicon into the single crystal member, and its manufacture Regarding the method.
従来、単結晶のシリコン（Ｓｉ）ウエハに代表される半導体ウエハを製造する場合には、石英るつぼ内に溶融されたシリコン融液から凝固した円柱形のインゴットを適切な長さのブロックに切断して、その周縁部を目標の直径になるよう研削し、その後、ブロック化されたインゴットをワイヤソーによりウエハ形にスライスして半導体ウエハを製造するようにしている。 Conventionally, when manufacturing a semiconductor wafer typified by a single crystal silicon (Si) wafer, a cylindrical ingot solidified from a silicon melt melted in a quartz crucible is cut into blocks of an appropriate length. Then, the peripheral edge is ground to a target diameter, and then the block-shaped ingot is sliced into a wafer shape with a wire saw to manufacture a semiconductor wafer.
このようにして製造された半導体ウエハは、前工程で回路パターンの形成等、各種の処理が順次施されて後工程に供され、この後工程で裏面がバックグラインド処理されて薄片化が図られることにより、厚さが約７５０μｍから１００μｍ以下、例えば７５μｍや５０μｍ程度に調整される。 The semiconductor wafer thus manufactured is subjected to various processes such as formation of a circuit pattern in the previous process in order and used for the subsequent process, and the back surface is back-ground processed in the subsequent process to achieve thinning. Accordingly, the thickness is adjusted to about 750 μm to 100 μm or less, for example, about 75 μm or 50 μm.
従来における半導体ウエハは、以上のように製造され、インゴットがワイヤソーにより切断され、しかも、切断の際にワイヤソーの太さ以上の切り代が必要となるので、厚さ０．１ｍｍ以下の薄い半導体ウエハを製造することが非常に困難であり、製品率も向上しないという問題がある。 A conventional semiconductor wafer is manufactured as described above, and an ingot is cut by a wire saw, and a cutting allowance larger than the thickness of the wire saw is required for cutting, so a thin semiconductor wafer having a thickness of 0.1 mm or less It is very difficult to manufacture the product, and the product rate is not improved.
一方、集光レンズでレーザ光の集光点をインゴット（ウエハ）の内部に合わせ、そのレーザ光でインゴットを相対的に走査することにより、インゴットの内部に多光子吸収による面状の加工層（改質層）を形成し、この加工層を剥離面としてインゴットの一部を基板として剥離することが開示されている（例えば、特許文献１参照）。 On the other hand, the focusing point of the laser beam is aligned with the inside of the ingot (wafer) by the condensing lens, and the ingot is relatively scanned with the laser beam. It is disclosed that a modified layer is formed and a part of the ingot is peeled off using the processed layer as a peeled surface (see, for example, Patent Document 1).
なお、この明細書中においては、別記する場合を除いてウエハのことを適宜に基板と称する。 In this specification, a wafer is appropriately referred to as a substrate unless otherwise specified.
しかし、単結晶部材内部に加工層を形成する場合、１つのレーザパルスで１点（１つ）の加工痕を形成している。このため、その加工間隔である加工ピッチは、加工進行方向へのステージ移動速度とパルス周波数で決まる。また、この加工ピッチと、オフセット方向（加工進行方向に直交する方向）の間隔である加工オフセットと、によって、単結晶部材内部に形成される加工痕の数（加工数）が決まる。 However, when forming a processed layer inside a single crystal member, one laser pulse forms one (one) processing mark. Therefore, the processing pitch, which is the processing interval, is determined by the stage moving speed and the pulse frequency in the processing progress direction. Further, the number of processing marks (the number of processing) formed inside the single crystal member is determined by the processing pitch and the processing offset that is an interval in the offset direction (direction orthogonal to the processing progress direction).
仮に、加工ピッチを１μｍ、加工オフセットを２μｍとすると、１００ｍｍ角（一辺が１００ｍｍの正方形）の領域を加工するには５０億パルスのレーザ光を照射する必要がある。この場合、パルス周波数を１００ｋＨｚとするとステージ移動速度は１００ｍｍ／ｓとなり、５０００秒、すなわち１４時間という長大な加工時間が必要となる。そこで、加工時間の短縮方法として、分岐ビームにより一度に複数のビームを照射すること方法が提案されている。また、仮に、加工ピッチと加工オフセットとを広げて剥離可能な条件を見い出したとしても、隣り合う加工痕の間の領域ではレーザ光による加工（改質）がなされていない。このため、例えば単結晶部材の厚み方向の位置によって剥離する高さ位置が異なり、剥離することが困難であったり、剥離できても剥離面の平坦性が低下することが考えられる。 Assuming that the processing pitch is 1 μm and the processing offset is 2 μm, it is necessary to irradiate 5 billion pulses of laser light to process a 100 mm square (100 mm square). In this case, if the pulse frequency is 100 kHz, the stage moving speed is 100 mm / s, and a long machining time of 5000 seconds, that is, 14 hours is required. Therefore, as a method for shortening the processing time, a method of irradiating a plurality of beams at once with a branched beam has been proposed. Even if the processing pitch and the processing offset are widened and a condition capable of peeling is found, processing (modification) by laser light is not performed in the region between adjacent processing marks. For this reason, for example, the height position at which the single crystal member is peeled differs depending on the position in the thickness direction, and it is difficult to peel off.
一方、単結晶部材を形成した内部加工層から分断させて新たな単結晶部材を創成することができる。この分断方法としては、内部加工層を形成した単結晶部材を、接着剤を用いて金属板で挟持して固定した後、金属板を互いに離れる方向の力を加えることにより剥離する方法、単結晶基板の側面から応力を印加してクラックを伝搬させて剥離する方法などが例示されている。しかしながら、こうした従来の方法により加工層から単結晶部材を分断させる方法においては、単結晶部材に応力が負荷あるいは印加されることによって単結晶部材の非加工層領域に衝撃や変形などが生じ、欠陥や転移などを発生させる可能性が高い。その結果、分断され創成された単結晶部材の品質劣化につながり、実使用上の不具合が生じる。さらに、これらの分断方法が求められる内部加工層結晶部材は、内部加工層が応力を負荷あるいは印加させないと分離できない状態であることを示唆している。従って、応力を負荷あるいは印加させなくても、形成した内部加工層から単結晶部材を分断および分離可能な加工層の形成方法が求められる。 On the other hand, it is possible to create a new single crystal member by dividing the inner processed layer on which the single crystal member is formed. As this dividing method, a method in which a single crystal member in which an internal processing layer is formed is sandwiched and fixed by a metal plate using an adhesive, and then peeled by applying a force in a direction away from each other, a single crystal Examples include a method in which stress is applied from the side surface of a substrate to propagate a crack and peel off. However, in the method of dividing the single crystal member from the processed layer by such a conventional method, a stress or deformation is caused in the non-processed layer region of the single crystal member due to stress being applied to or applied to the single crystal member. And is likely to cause metastasis. As a result, the quality of the divided and created single crystal member is deteriorated, resulting in problems in actual use. Furthermore, it is suggested that the internally processed layer crystal member that requires these cutting methods cannot be separated unless the internal processed layer is loaded or applied with stress. Therefore, there is a need for a method for forming a processed layer that can divide and separate the single crystal member from the formed internal processed layer without applying or applying stress.
本発明は、上記課題に鑑み、シリコンの単結晶部材に形成した加工層から剥離させることで比較的大きくて薄いシリコンの単結晶基板を形成するにあたり、応力を負荷せずに剥離可能であり、剥離面の平坦性を確保しつつ加工時間の短縮化を図ることができる内部加工層形成単結晶部材およびその製造方法を提供することを課題とする。 In view of the above problems, the present invention is capable of peeling without applying stress when forming a relatively large and thin silicon single crystal substrate by peeling from a processed layer formed on a silicon single crystal member. It is an object of the present invention to provide an internally processed layer-forming single crystal member capable of shortening the processing time while ensuring the flatness of the release surface, and a method for manufacturing the same.
上記課題を解決するための本発明の一態様によれば、レーザ光を集光するレーザ集光手段を介してレーザ光をシリコンの単結晶部材の被照射面から照射しつつ、前記単結晶部材と前記レーザ集光手段とを相対的に移動させることで、前記単結晶部材内部に形成された加工層と、前記加工層の両面側にそれぞれ隣接する非加工部と、を備え、前記加工層には、複数のレーザ光の集光によってそれぞれ形成された複数の加工痕が一方向に連なってなる変質部が、レーザ光の走査方向およびオフセット方向にそれぞれ複数個配列され、かつ、レーザ光の走査方向に隣り合う変質部同士に跨るクラック、および、レーザ光のオフセット方向に隣り合う変質部同士に跨るクラックの少なくとも一方が形成されているとともに、前記クラックの前記被照射面からの深さ位置が略同一深さ位置である内部加工層形成単結晶部材が提供される。 According to one aspect of the present invention for solving the above-described problem, the single crystal member is irradiated with laser light from the irradiated surface of the single crystal member of silicon via a laser condensing unit that condenses the laser light. And the laser condensing means are relatively moved to provide a processed layer formed inside the single crystal member, and a non-processed portion adjacent to both sides of the processed layer, and the processed layer The plurality of altered portions in which a plurality of processing marks respectively formed by condensing a plurality of laser beams are arranged in one direction are arranged in each of the scanning direction and the offset direction of the laser beams, and At least one of a crack straddling the deteriorated portions adjacent in the scanning direction and a crack straddling the deteriorated portions adjacent in the offset direction of the laser beam is formed, and the irradiation of the crack Depth position from are substantially the same depth position inside the working layer formed single crystal member.
本発明の別の態様によれば、レーザ光を集光するレーザ集光手段を介してレーザ光をシリコンの単結晶部材の被照射面から照射しつつ、前記単結晶部材と前記レーザ集光手段とを相対的に移動させることで、前記単結晶部材内部に加工層を形成して前記単結晶部材を内部加工層形成単結晶部材とする内部加工層形成単結晶部材の製造方法であって、前記加工層を形成する際、複数のレーザ光による複数の加工痕が一方向に連なってなる変質部を、レーザ光の走査方向に隣り合う変質部同士に跨るクラック、および、レーザ光のオフセット方向に隣り合う変質部同士に跨るクラックの少なくとも一方が生じるとともに前記クラックの前記被照射面からの深さ位置が略同一深さ位置にとなるように形成していく内部加工層形成単結晶部材の製造方法が提供される。 According to another aspect of the present invention, the single crystal member and the laser condensing means are irradiated while irradiating the laser light from the irradiated surface of the single crystal member of silicon through the laser condensing means for condensing the laser light. And the relative movement of the single crystal member, forming a processed layer inside the single crystal member, and using the single crystal member as an internal processed layer forming single crystal member, When forming the processed layer, a crack that spans the deteriorated portions adjacent to each other in the scanning direction of the laser light, and the offset direction of the laser light, the deteriorated portion in which a plurality of processing marks by a plurality of laser beams are continuous in one direction Of the internally processed layer forming single crystal member formed such that at least one of the cracks straddling the deteriorated portions adjacent to each other occurs and the depth position of the crack from the irradiated surface is substantially the same depth position. Manufacturing method There is provided.
本発明によれば、シリコンの単結晶部材に形成した加工層から剥離させることで比較的大きくて薄いシリコンの単結晶基板を形成するにあたり、応力を負荷せずに剥離可能であり、剥離面の平坦性を確保しつつ加工時間の短縮化を図ることができる内部加工層形成単結晶部材およびその製造方法を提供することができる。 According to the present invention, when a relatively large and thin silicon single crystal substrate is formed by peeling from a processed layer formed on a silicon single crystal member, it can be peeled without applying stress. It is possible to provide an internally processed layer-forming single crystal member capable of reducing the processing time while ensuring flatness, and a method for manufacturing the same.
以下、添付図面を参照して、本発明の実施の形態について説明する。以下の説明では、すでに説明したものと同一または類似の構成要素には同一または類似の符号を付し、その詳細な説明を適宜省略している。 Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description, the same or similar components as those already described are denoted by the same or similar reference numerals, and detailed description thereof is omitted as appropriate.
また、図面は模式的なものであり、寸法比などは現実のものとは異なることに留意すべきである。従って、具体的な寸法比などは以下の説明を参酌して判断すべきものである。
又、図面相互間においても互いの寸法の関係や比率が異なる部分が含まれていることはもちろんである。
In addition, it should be noted that the drawings are schematic and the dimensional ratios and the like are different from actual ones. Therefore, specific dimensional ratios and the like should be determined in consideration of the following description.
Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.
また、以下に示す実施の形態は、この発明の技術的思想を具体化するための例示であって、この発明の実施の形態は、構成部品の材質、形状、構造、配置等を下記のものに特定するものではない。この発明の実施の形態は、要旨を逸脱しない範囲内で種々変更して実施できる。 The following embodiments are exemplifications for embodying the technical idea of the present invention, and the embodiments of the present invention are described below in terms of the material, shape, structure, arrangement, etc. of the components. It is not something specific. The embodiments of the present invention can be implemented with various modifications without departing from the scope of the invention.
図１は、本発明の一実施形態（以下、本実施形態という）で、レーザ集光手段により単結晶部材１０の被照射面（被照射側の表面）からレーザ光を集光して内部に加工層２１を形成していくことを説明する模式的な鳥瞰図である。図２は、レーザ光の照射により単結晶部材１０の内部に加工層２１を形成して内部加工層形成単結晶部材を形成することを説明する模式的な断面図である。図３は、本実施形態で製造された内部加工層形成単結晶部材２０の断面構造を説明する模式的な側面断面図である。図４は、本実施形態で、内部加工層形成単結晶部材を製造することを説明する側面図であり、本実施形態におけるレーザ加工装置の一例の全体図も示している。図５（ａ）および（ｂ）は、それぞれ、本発明の一実施形態で、集光器から出射したレーザ光によって単結晶部材に加工層を形成することを説明する模式的な平面図および模式的な側面断面図である。 FIG. 1 shows an embodiment of the present invention (hereinafter referred to as the present embodiment), in which laser light is condensed from an irradiated surface (surface on the irradiated side) of a single crystal member 10 by laser focusing means. It is a typical bird's-eye view explaining explaining that the processing layer 21 is formed. FIG. 2 is a schematic cross-sectional view for explaining that the processed layer 21 is formed inside the single crystal member 10 by irradiation with laser light to form the internal processed layer forming single crystal member. FIG. 3 is a schematic side cross-sectional view for explaining the cross-sectional structure of the internally processed layer-forming single crystal member 20 manufactured in the present embodiment. FIG. 4 is a side view for explaining the production of the internally processed layer-forming single crystal member in the present embodiment, and also shows an overall view of an example of the laser processing apparatus in the present embodiment. FIGS. 5A and 5B are a schematic plan view and a schematic view for explaining that a processed layer is formed on a single crystal member by laser light emitted from a condenser, respectively, in one embodiment of the present invention. FIG.
図６（ａ）および（ｂ）は、それぞれ、本発明の一実施形態で、内部加工層形成単結晶部材の構成を説明する模式的な側面部分断面図、および、（ａ）の部分拡大図である。図７（ａ）および（ｂ）は、それぞれ、本発明の一実施形態で、内部加工層形成単結晶部材の構成を説明する模式的な側面部分断面図、および、（ａ）の部分拡大図である。なお、図６で示す側面断面と図７で示す側面断面とは互いに直交する平面である。また、図６（ａ）および図７（ａ）では、簡明化のため後述のクラックＣＳ、ＣＦを省略して描いている。図８は、本発明の一実施形態で、内部加工層形成単結晶部材を説明する模式的な側面断面図である。 6 (a) and 6 (b) are a schematic side sectional view for explaining the structure of the internally processed layer-forming single crystal member and a partially enlarged view of (a), respectively, in one embodiment of the present invention. It is. 7 (a) and 7 (b) are a schematic side partial sectional view for explaining the configuration of an internally processed layer-forming single crystal member, and a partially enlarged view of (a), respectively, according to an embodiment of the present invention. It is. 6 and the side cross section shown in FIG. 7 are planes orthogonal to each other. Further, in FIGS. 6A and 7A, cracks CS and CF, which will be described later, are omitted for simplicity. FIG. 8 is a schematic side cross-sectional view for explaining an internally processed layer-forming single crystal member according to an embodiment of the present invention.
（概要説明）
本実施形態で製造する内部加工層形成単結晶部材２０は、パルス状のレーザ光Ｂをシリコンの単結晶部材１０の被照射面２０ｔから集光することで、この被照射面２０ｔと離間しかつこの被照射面２０ｔと平行に延在する加工層２１と、その加工層２１の両面側にそれぞれ隣接する非加工層２２とを有する。
(Overview)
The internally processed layer-forming single crystal member 20 manufactured in this embodiment is separated from the irradiated surface 20t by condensing the pulsed laser beam B from the irradiated surface 20t of the silicon single crystal member 10, and It has a processed layer 21 extending in parallel with the irradiated surface 20t, and a non-processed layer 22 adjacent to each side of the processed layer 21.
加工層２１には、レーザ光Ｂの集光によって形成された変質部２１ｃ（図５参照）が規則的に配列されている。各変質部２１ｃは、ビームスプリッタの機能を有する回折光学素子（ＤＯＥ、Diffractive Optics Element）７２で分割されてなる複数のレーザ光ＢＤが
それぞれ集光したことによる複数の加工痕２１ｓ（図５参照）からなる。ここで、ビームスプリッタの機能を有する回折光学素子７２で分割されてなる複数のレーザ光ＢＤでは、各ビームのパワーが均一であるが、少なくとも、各ビームパワーの平均値に対してのばらつきが±０．５％以内であることが好ましい。
Altered portions 21c (see FIG. 5) formed by condensing the laser beam B are regularly arranged in the processed layer 21. Each altered portion 21c has a plurality of processing marks 21s (see FIG. 5) formed by condensing a plurality of laser beams BD divided by a diffractive optical element (DOE, Diffractive Optics Element) 72 having a beam splitter function. Consists of. Here, in the plurality of laser beams BD divided by the diffractive optical element 72 having the function of a beam splitter, the power of each beam is uniform, but at least the variation with respect to the average value of each beam power is ± It is preferably within 0.5%.
また、加工層２１には、レーザ光Ｂの集光によって形成された変質部２１ｃが、レーザ光の走査方向Ｓおよびオフセット方向Ｆにそれぞれ規則的に配列されている。そして、本実施形態では、レーザ光の走査方向Ｓに隣り合う変質部同士に跨るクラックＣＳ（図５、６参照）、および、レーザ光のオフセット方向Ｆに隣り合う変質部同士に跨るクラックＣＦ（図５、６参照）が形成されている。これらクラックＣＳおよびＣＦはレーザ光Ｂにより形成された変質部２１ｃから面状に拡がって形成されており、断面方向においては変質部２１ｃのレーザ照射面側に形成されていて、変質部同士に跨っている。 In the processed layer 21, altered portions 21c formed by condensing the laser beam B are regularly arranged in the scanning direction S and the offset direction F of the laser beam. In this embodiment, the crack CS (see FIGS. 5 and 6) straddling the deteriorated portions adjacent to each other in the scanning direction S of the laser light and the crack CF (see FIG. 5) straddling the deteriorated portions adjacent to each other in the offset direction F of the laser light. (See FIGS. 5 and 6). These cracks CS and CF are formed so as to extend in a planar shape from the altered portion 21c formed by the laser beam B, and are formed on the laser irradiation surface side of the altered portion 21c in the cross-sectional direction and straddle the altered portions. ing.
図６〜図８に示すように、クラックＣＳ、クラックＣＦの何れであっても、各クラックは単結晶部材１０の被照射面２０ｔから略同一深さ位置に形成されている。ここで、略同一深さとは、加工層２１の寸法にもよるが、深さ位置の差が３μｍ以下（加工層２１の寸法が小さい場合には２μｍ以下）のことをいう。この深さ位置が３μｍを超えると、剥離時応力負荷あるいは印加が必要となり、さらに剥離応力がおおきくなることで単結晶部材の品質劣化や、剥離面の平坦性低下をもたらす。また、変質部２１ｃは、複数の加工痕２１ｓが一方向に連なったものであり、この一方向はレーザ光の走査方向Ｓである。従って、剥離面がより平坦面になりやすい。ここで、平坦面とは、ＪＩＳ Ｂ０６０１における算術平均粗さＲａで示され、このＲａが５．０μｍ以下、より好ましくは３．０μｍ以下であることが、単結晶部材の後加工を容易にする点で好ましい。 As shown in FIGS. 6 to 8, each crack is formed at substantially the same depth position from the irradiated surface 20 t of the single crystal member 10, whether it is a crack CS or a crack CF. Here, “substantially the same depth” refers to a difference in depth position of 3 μm or less (or 2 μm or less when the dimension of the processing layer 21 is small), although it depends on the size of the processing layer 21. When this depth position exceeds 3 μm, it is necessary to apply a stress load or application at the time of peeling, and the peeling stress increases, resulting in deterioration of the quality of the single crystal member and a reduction in flatness of the peeling surface. The altered portion 21c has a plurality of machining marks 21s connected in one direction, and this one direction is the scanning direction S of the laser beam. Therefore, the peeling surface tends to be a flat surface. Here, the flat surface is represented by an arithmetic average roughness Ra in JIS B0601, and the Ra is 5.0 μm or less, more preferably 3.0 μm or less to facilitate post-processing of the single crystal member. This is preferable.
内部加工層形成単結晶部材２０を製造して単結晶基板を得るには、レーザ集光手段として例えば集光器（組レンズ）７８により、単結晶部材１０の被照射面２０ｔに、調整したレーザ光Ｂを照射して単結晶部材１０内部にレーザ光Ｂを集光しつつ、集光器７８と単結晶部材１０とを相対的に移動させて、単結晶部材１０内部に、被照射面２０ｔと平行に延在する加工層２１を形成した内部加工層形成単結晶部材２０を製造する。 In order to manufacture the single crystal member 20 with the inner processed layer formation and obtain a single crystal substrate, a laser adjusted to the irradiated surface 20t of the single crystal member 10 by, for example, a condenser (assembled lens) 78 as a laser condensing unit. While condensing the laser beam B inside the single crystal member 10 by irradiating the light B, the concentrator 78 and the single crystal member 10 are moved relative to each other so that the irradiated surface 20 t The internal processing layer forming single crystal member 20 in which the processing layer 21 extending in parallel with the base material is formed.
その際、本実施形態では、レーザ集光手段に回折光学素子７２を設け、回折光学素子７２で分割された複数のレーザ光ＢＤを、集光器７８を介して単結晶部材１０の被照射面２０ｔから照射し、複数の集光点Ｄを同時に形成することで変質部２１ｃを形成していくことで加工層２１を形成する。単結晶部材１０としては、レーザ光Ｂを照射する被照射面２０ｔ（第１面）と、被照射面２０ｔに平行であって被照射面２０ｔに照射したレーザ光Ｂが通過する光出射面２０ｓ（第２面）と、を有する部材を用いる。 At this time, in the present embodiment, the diffractive optical element 72 is provided in the laser condensing unit, and a plurality of laser beams BD divided by the diffractive optical element 72 are irradiated onto the surface of the single crystal member 10 via the condenser 78. The processed layer 21 is formed by forming the altered portion 21 c by irradiating from 20 t and simultaneously forming a plurality of condensing points D. The single crystal member 10 includes an irradiated surface 20t (first surface) that irradiates laser light B, and a light emitting surface 20s that is parallel to the irradiated surface 20t and through which the laser light B irradiated to the irradiated surface 20t passes. (Second surface) is used.
また、変質部２１ｃを形成する際、クラックＣＳおよびクラックＣＦが形成されるように変質部２１ｃを形成していく。単結晶部材１０としては、レーザ光Ｂを照射する被照射面２０ｔ（第１面）と、被照射面２０ｔに平行であって被照射面２０ｔに照射したレーザ光Ｂが通過する光出射面２０ｓ（第２面）と、を有する部材を用いる。 Further, when forming the altered portion 21c, the altered portion 21c is formed so that the crack CS and the crack CF are formed. The single crystal member 10 includes an irradiated surface 20t (first surface) that irradiates laser light B, and a light emitting surface 20s that is parallel to the irradiated surface 20t and through which the laser light B irradiated to the irradiated surface 20t passes. (Second surface) is used.
（詳細説明）
以下、本実施形態をより詳細に説明する。本実施形態では、図４に示すように、レーザ加工装置は、レーザ発振器７１、回折光学素子７２、凸レンズ（対物レンズ）７４、集光器７８を順次備え、また、ＸＹステージ８０を備えている。集光器７８は複数のレンズが組み合わされた組レンズとなっており、集光性能が高くされている。
(Detailed explanation)
Hereinafter, this embodiment will be described in more detail. In the present embodiment, as shown in FIG. 4, the laser processing apparatus includes a laser oscillator 71, a diffractive optical element 72, a convex lens (objective lens) 74, a condenser 78, and an XY stage 80. . The concentrator 78 is a combined lens in which a plurality of lenses are combined, and has high condensing performance.
本実施形態では、レーザ発振器７１からのレーザ光Ｂは、回折光学素子７２を通過することによって複数のレーザ光ＢＤに分割される。そして、この複数のレーザ光ＢＤは凸レンズ７４、集光器７８を順次通過し、単結晶部材１０内部でレーザ光が集光されるようになっている。この構成により回折光学素子７２で分割された複数のレーザ光ＢＤを集光する集光レンズ群８２が、凸レンズ７４および集光器７８によって形成されている。 In the present embodiment, the laser beam B from the laser oscillator 71 is split into a plurality of laser beams BD by passing through the diffractive optical element 72. Then, the plurality of laser beams BD sequentially pass through the convex lens 74 and the condenser 78, and the laser beams are condensed inside the single crystal member 10. With this configuration, a condensing lens group 82 that condenses the plurality of laser beams BD divided by the diffractive optical element 72 is formed by a convex lens 74 and a concentrator 78.
本実施形態では、回折光学素子７２は、１本のレーザ光が入射すると、同一平面内を進み、かつ、隣り合うレーザ光同士のなす角度が均等となるような複数のレーザ光に分割して出射するようになっている。本実施形態では、この同一平面は、レーザ光の走査方向Ｓに直交する平面となっているが、直交しなくてもよい。 In the present embodiment, the diffractive optical element 72 is divided into a plurality of laser beams that travel in the same plane when one laser beam is incident and the angles formed by adjacent laser beams are equal. It comes out. In the present embodiment, the same plane is a plane orthogonal to the scanning direction S of the laser beam, but it does not have to be orthogonal.
レーザ光を照射する単結晶部材１０のサイズは、例えばφ３００ｍｍの厚いシリコンウエハＥからなり、レーザ光Ｂが照射される被照射面Ｅｔが予め平坦化されていることが好ましい。 The size of the single crystal member 10 to be irradiated with the laser light is preferably made of, for example, a thick silicon wafer E having a diameter of 300 mm, and the irradiated surface Et irradiated with the laser light B is preferably planarized in advance.
レーザ光Ｂは、単結晶部材１０の周面ではなく、上記の被照射面２０ｔに集光器７８を介して照射される。このレーザ光Ｂは、例えばパルス幅が１μｓ以下のパルスレーザ光からなり、９００ｎｍ以上の波長、好ましくは１０００ｎｍ以上の波長が選択され、ＹＡＧレーザ等が好適に使用される。 The laser beam B is applied to the irradiated surface 20t, not the peripheral surface of the single crystal member 10, via the condenser 78. This laser beam B is composed of, for example, a pulse laser beam having a pulse width of 1 μs or less, and a wavelength of 900 nm or more, preferably 1000 nm or more is selected, and a YAG laser or the like is preferably used.
（作用、効果）
以下、本実施形態で内部加工層形成単結晶部材１０を製造することについて説明する。本実施形態では、単結晶部材１０をＸＹステージ上に載置し、真空チャック、静電チャックなどでこの単結晶部材１０を保持する。そして、ＸＹステージで単結晶部材１０をＸ方向やＹ方向に移動させることで、レーザ集光手段（回折光学素子７２、凸レンズ７４、および、集光器７８）と単結晶部材１０とを、単結晶部材１０の被照射面２０ｔに平行に相対的に移動させながらレーザ光Ｂを照射することで、単結晶部材１０の内部に集光したレーザ光Ｂによって加工層２１を形成する。
(Function, effect)
Hereinafter, manufacturing the internally processed layer-forming single crystal member 10 in this embodiment will be described. In this embodiment, the single crystal member 10 is placed on an XY stage, and the single crystal member 10 is held by a vacuum chuck, an electrostatic chuck, or the like. Then, by moving the single crystal member 10 in the X direction or the Y direction on the XY stage, the laser condensing means (the diffractive optical element 72, the convex lens 74, and the concentrator 78) and the single crystal member 10 are made single. By irradiating the laser beam B while relatively moving in parallel with the irradiated surface 20t of the crystal member 10, the processed layer 21 is formed by the laser beam B condensed inside the single crystal member 10.
その際、ビームスプリッタ７２に入射したレーザ光Ｂは複数のレーザ光ＢＤ（分岐レーザ光）となって凸レンズ７４を通過し、更に、集光器７８を通過する。集光器７８から出射した複数のレーザ光は、被照射面２０ｔでは集光せずに単結晶部材１０の内部で集光して複数の集光点を形成する。この結果、図５に示すように、変質部２１ｃがレーザ走査方向に一列に規則的に形成されていく。 At that time, the laser beam B incident on the beam splitter 72 becomes a plurality of laser beams BD (branched laser beams), passes through the convex lens 74, and further passes through the condenser 78. The plurality of laser beams emitted from the condenser 78 are not condensed on the irradiated surface 20t, but are condensed inside the single crystal member 10 to form a plurality of condensing points. As a result, as shown in FIG. 5, the altered portions 21c are regularly formed in a line in the laser scanning direction.
本実施形態では、この変質部２１ｃは、複数の加工痕２１ｓが一方向に連なった擬似ライン状のものであり、この一方向は、レーザ光の走査方向Ｓ（加工進行方向）に直交する方向となる。複数のレーザ光ＢＤは、例えば、２０本のレーザ光であり、この場合、複数の加工痕２１ｓの個数は２０個となる。 In the present embodiment, the altered portion 21c has a pseudo-line shape in which a plurality of processing marks 21s are connected in one direction, and this one direction is a direction orthogonal to the scanning direction S (processing progress direction) of the laser beam. It becomes. The plurality of laser beams BD are, for example, 20 laser beams, and in this case, the number of processing marks 21s is 20.
また、オフセット方向Ｆに隣り合う変質部２１ｃ同士の距離Ｌは、加工痕２１ｓのオフセット方向Ｆの幅ｅ（図５（ｂ）参照）よりも長い。ここで、上記の距離Ｌは、オフセット方向Ｆに隣り合う一方の変質部２１ｃの加工痕２１ｓと他方の変質部２１ｃの加工痕２１ｓとの距離のうち、最も近い加工痕同士の中心間距離のことである。 Further, the distance L between the altered portions 21c adjacent to each other in the offset direction F is longer than the width e (see FIG. 5B) of the machining trace 21s in the offset direction F. Here, the distance L is the distance between the centers of the nearest processing marks among the distances between the processing marks 21s of the one altered portion 21c adjacent to the offset direction F and the processing marks 21s of the other altered portion 21c. That is.
また、本実施形態では、加工痕２１ｓのピッチｋ（隣り合うレーザ光ＢＤの照射中心同士の間隔）は、加工痕２１ｓが連なるように３μｍ以下（例えば１μｍあるいは２μｍ）にされている。ピッチｋは、分割された複数の各レーザ光のパワーなどに応じて決定することが好ましい。 In this embodiment, the pitch k of the processing marks 21s (the interval between the irradiation centers of the adjacent laser beams BD) is 3 μm or less (for example, 1 μm or 2 μm) so that the processing marks 21s are continuous. The pitch k is preferably determined according to the power of each of the divided laser beams.
変質部２１ｃを一列に形成した後、単結晶部材１０とレーザ集光手段とを、レーザ走査方向に直交するオフセット方向Ｆに相対的に移動させ、同様に変質部２１ｃを一列に形成していく。オフセット間隔ｗは、例えば、１４μｍであり、加工層２１の両側の非加工層２２が剥離可能である限り自由に変更することが可能である。 After the altered portions 21c are formed in a row, the single crystal member 10 and the laser condensing means are moved relatively in the offset direction F perpendicular to the laser scanning direction, and the altered portions 21c are similarly formed in a row. . The offset interval w is, for example, 14 μm, and can be freely changed as long as the non-processed layer 22 on both sides of the processed layer 21 can be peeled off.
そして本実施形態では、この変質部２１ｃを形成する際、レーザ光の走査方向Ｓに隣り合う変質部２１ｃの間隔である加工ピッチｐを１〜１０μｍの範囲とする。 And in this embodiment, when forming this quality change part 21c, the process pitch p which is the space | interval of the quality change part 21c adjacent to the scanning direction S of a laser beam is made into the range of 1-10 micrometers.
また、レーザ光のオフセット方向Ｆに隣り合う変質部２１ｃの間隔である加工オフセットｗを１〜１０μｍの範囲（更に好ましくは１．５〜３．５μｍの範囲）とする。 Further, the processing offset w that is the interval between the altered portions 21c adjacent to each other in the offset direction F of the laser light is set to a range of 1 to 10 μm (more preferably, a range of 1.5 to 3.5 μm).
この結果、変質部２１ｃを形成していく際、図５、図６に示すように、レーザ光の走査方向Ｓに隣り合う変質部２１ｃ同士を跨るクラックＣＳが生じ、また、レーザ光のオフセット方向Ｆに隣り合う変質部２１ｃ同士を跨るクラックＣＦが生じる。変質部２１ｃはレーザ光Ｂの照射方向（例えば、レーザ光Ｂが上方から下方へ向けて照射される場合には上下方向）に沿って細長く形成されおり、クラックＣＳ、ＣＦは、変質部２１ｃの照射側に発生する。従って、クラックＣＳ、ＣＦは、被照射面２０ｔから略同一深さ位置に形成される。 As a result, when the altered portion 21c is formed, as shown in FIGS. 5 and 6, a crack CS straddling the altered portions 21c adjacent to each other in the scanning direction S of the laser beam occurs, and the offset direction of the laser beam Cracks CF straddling the altered portions 21c adjacent to F occur. The altered portion 21c is formed to be elongated along the irradiation direction of the laser beam B (for example, the vertical direction when the laser beam B is irradiated from above to below), and the cracks CS and CF are formed on the altered portion 21c. Occurs on the irradiation side. Accordingly, the cracks CS and CF are formed at substantially the same depth position from the irradiated surface 20t.
クラックＣＳ、ＣＦを更に均一に安定して生じさせる観点では、加工ピッチｐを１．５〜３．５μｍの範囲とすることが更に好ましく、また、加工オフセットｗも１．５〜３．５μｍの範囲とすることが更に好ましい。クラックＣＳ、ＣＦの形成にかかる時間を短縮するには、加工ピッチｐ、加工オフセットｗを大きくする。 From the viewpoint of generating the cracks CS and CF more uniformly and stably, it is more preferable that the processing pitch p is in the range of 1.5 to 3.5 μm, and the processing offset w is also 1.5 to 3.5 μm. More preferably, it is within the range. In order to shorten the time required for forming the cracks CS and CF, the processing pitch p and the processing offset w are increased.
加工層２１が形成された結果、加工層２１を挟んでレーザ光Ｂの照射方向とその反対側にそれぞれ非加工層２２が加工層２１に隣接して存在する。形成する加工層２１の寸法、密度などは、剥離し易くする観点で設定することが好ましい。 As a result of forming the processed layer 21, the non-processed layer 22 exists adjacent to the processed layer 21 on the opposite side to the irradiation direction of the laser beam B across the processed layer 21. The dimensions, density, and the like of the processed layer 21 to be formed are preferably set from the viewpoint of facilitating peeling.
上記したようにレーザ光Ｂが均一パワーを有するものであると、加工層深さ位置が略均一となるように深さ位置の差が３μｍ以下（加工層２１の寸法が小さい場合には２μｍ以下）で形成され、加工層２１と非加工層２２との間には、連続する境界２３が形成されるため、加工層２１と非加工層２２とで応力を負荷あるいは印加させないで剥離が可能となる。一方、この状態で加工されない場合、加工層２１の形成状態にクラックや加工状態の異なる加工層が作り出されて、連続した境界が形成されにくい。その結果、加工層２１の全面での剥離ができなかったり、単結晶部材の結晶方位に沿って劈開したりすることが生じ易い。 As described above, when the laser beam B has a uniform power, the difference in depth position is 3 μm or less so that the depth position of the processing layer is substantially uniform (2 μm or less when the dimension of the processing layer 21 is small). ), And a continuous boundary 23 is formed between the processed layer 21 and the non-processed layer 22, so that the processed layer 21 and the non-processed layer 22 can be separated without applying or applying stress. Become. On the other hand, if not processed in this state, a processed layer having a crack or a processed state is created in the formed state of the processed layer 21, and it is difficult to form a continuous boundary. As a result, it is easy to occur that the processed layer 21 cannot be peeled over the entire surface or cleaved along the crystal orientation of the single crystal member.
本発明において、応力を負荷あるいは印加しないで単結晶部材を分断あるいは分離できるということは、内部加工層形成後に自ら分断あるいは剥離できる状態であり、剥離荷重は１０Ｎ/ｃｍ2以下である。 In the present invention, the fact that a single crystal member can be divided or separated without applying or applying stress is a state in which it can be divided or separated by itself after the formation of the internal working layer, and the peeling load is 10 N / cm 2 or less.
剥離後、この剥離面（加工層露出面）は平坦であり、その表面粗さはＲａ＝５．０μｍ以下である。さらに、ラッピング加工およびポリシング加工により研磨加工してもよい。
研磨加工は例えばラッピング・ポリシング装置を利用して行うことができる。ラッピングでは研磨剤として粒径が１μｍから数１０μｍの遊離砥粒を潤滑剤に混ぜたスラリーをラップ定盤と上記の加工層露出面との間に入れ加工する。このときの遊離砥粒としてはコロイダルシリカ、アルミナ、微粒ダイヤモンド、酸化セリウムなどが利用できる。ポリシング加工では粒径１μｍ以下の微細な研磨剤が使用され、研磨パッドを定盤に貼りつけて加工層露出面を研磨加工する。
After peeling, the peeled surface (processed layer exposed surface) is flat, and the surface roughness is Ra = 5.0 μm or less. Furthermore, polishing may be performed by lapping and polishing.
The polishing process can be performed using, for example, a lapping / polishing apparatus. In lapping, a slurry obtained by mixing free abrasive grains having a particle size of 1 μm to several tens of μm as a polishing agent with a lubricant is placed between a lapping plate and the exposed surface of the processed layer. As the free abrasive grains at this time, colloidal silica, alumina, fine diamond, cerium oxide, or the like can be used. In the polishing process, a fine abrasive having a particle size of 1 μm or less is used, and the exposed surface of the processed layer is polished by attaching a polishing pad to a surface plate.
以上説明したように、本実施形態では、加工層２１を形成する際、１本のレーザ光Ｂを回折光学素子７２で分割して複数のレーザ光ＢＤにし、単結晶部材１０内部でこの複数のレーザ光ＢＤを集光させることで、複数の加工痕２１ｓが連なってなる変質部２１ｃを順次形成している。従って、１本のレーザ光Ｂを単結晶部材１０に入射させて１つの集光点を形成する従来例に比べ、加工層２１の形成速度を格段に速くすることができる。例えば、本実施形態で加工痕２１ｃのピッチｋを０．５μｍにすると、回折光学素子７２でレーザ光Ｂを２０本に分割する場合には、変質部２１ｃの長さｄが約１０μｍとなり、この加工幅で走査方向Ｓに変質部２１ｃを規則的に順次形成していくことができる。なお、変質部２１ｃの長さｄとは、図５に示すように、変質部２１ｃの両端部に位置する加工痕２１ｓ同士の中心線間の距離のことである。 As described above, in the present embodiment, when the processed layer 21 is formed, one laser beam B is divided by the diffractive optical element 72 into a plurality of laser beams BD, and the plurality of laser beams BD are formed inside the single crystal member 10. By condensing the laser beam BD, an altered portion 21c in which a plurality of machining marks 21s are connected is sequentially formed. Therefore, the formation speed of the processed layer 21 can be remarkably increased as compared with the conventional example in which one laser beam B is incident on the single crystal member 10 to form one condensing point. For example, when the pitch k of the machining mark 21c is 0.5 μm in this embodiment, when the laser beam B is divided into 20 by the diffractive optical element 72, the length d of the altered portion 21c is about 10 μm. The altered portions 21c can be regularly and sequentially formed in the scanning direction S with the processing width. The length d of the altered portion 21c is the distance between the center lines of the processing marks 21s located at both ends of the altered portion 21c, as shown in FIG.
また、距離Ｌは、加工痕２１ｓのオフセット方向Ｆの幅ｅよりも大きくされており、加工オフセットｗを効率的に広げることができ、従って、内部加工層形成単結晶部材２０の製造時間を効率的に短縮させることができる。 Further, the distance L is larger than the width e of the machining trace 21s in the offset direction F, so that the machining offset w can be efficiently widened. Therefore, the manufacturing time of the internally processed layer forming single crystal member 20 is efficiently increased. Can be shortened.
また、回折光学素子７２で１本のレーザ光Ｂを複数のレーザ光ＢＤに分割しているので、複数の集光点を単結晶部材１０内部に形成するにあたってレーザ発振器７１を複数台設ける必要がないので、装置構成を簡素にできる。 In addition, since one laser beam B is divided into a plurality of laser beams BD by the diffractive optical element 72, it is necessary to provide a plurality of laser oscillators 71 when forming a plurality of condensing points inside the single crystal member 10. Since there is no device configuration, the device configuration can be simplified.
また、回折光学素子７２により、簡単な構造で複数のレーザ光（例えば３〜１００本のレーザ光）に容易に分割することができ、しかも、各レーザ光の強度分布を均一にすることができる。その上、変質部２１ｃを構成する複数の加工痕２１ｓは同時に形成される。
従って、加工痕が形成された後に更に加工痕が形成されてレーザ光の散乱などが生じることは回避されており、加工痕２１ｓのサイズが安定する。よって、非加工層２２の剥離面（加工層２１からの剥離面）の平坦性が向上する。なお、レーザ光の出力、回折光学素子７２の構造などに応じてレーザ光の分岐本数を適宜変更することが好ましい。
Further, the diffractive optical element 72 can be easily divided into a plurality of laser beams (for example, 3 to 100 laser beams) with a simple structure, and the intensity distribution of each laser beam can be made uniform. . In addition, a plurality of machining marks 21s constituting the altered portion 21c are formed at the same time.
Therefore, it is avoided that the processing trace is further formed after the processing trace is formed and the laser beam is scattered, and the size of the processing trace 21s is stabilized. Therefore, the flatness of the peeled surface of the non-processed layer 22 (the peeled surface from the processed layer 21) is improved. Note that it is preferable to appropriately change the number of branches of the laser light according to the output of the laser light, the structure of the diffractive optical element 72, and the like.
また、集光器７８は組レンズで構成されており、高い集光性能で単結晶部材１０の内部で集光する。従って、加工精度が大きく向上する。 The concentrator 78 is composed of a combination lens and condenses inside the single crystal member 10 with high condensing performance. Accordingly, the processing accuracy is greatly improved.
また、本実施形態では、加工層２１を形成していく際、レーザ光の走査方向Ｓに隣り合う変質部２１ｃ同士を跨るクラックＣＳを生じさせ、また、レーザ光のオフセット方向Ｆに隣り合う変質部２１ｃ同士を跨るクラックＣＦを生じさせている。従って、加工層２１と非加工層２２とを剥離させる際、クラックＣＳ、ＣＦから剥離させることができるので、従来に比べて大幅に剥離させやすくなっている。よって、レーザ光の走査方向Ｓに隣り合う変質部２１ｃの加工ピッチｐ、および、レーザ光のオフセット方向Ｆに隣り合う変質部２１ｃの加工オフセットｗを従来に比べて大幅に広くすることができるので、変質部２１ｃの加工密度、すなわち変質部２１ｃの形成数を大幅に低減させることができる。従って、変質部２１ｃの加工時間が更に大幅に短縮され、内部加工層形成単結晶部材２０の製造効率が大きく向上する。また、剥離に必要な力も低減させることができる。 Further, in the present embodiment, when the processed layer 21 is formed, the crack CS straddling the altered portions 21c adjacent to each other in the scanning direction S of the laser beam is generated, and the altered alteration adjacent to the offset direction F of the laser beam is generated. A crack CF straddling the portions 21c is generated. Therefore, when the processed layer 21 and the non-processed layer 22 are peeled off, they can be peeled off from the cracks CS and CF. Therefore, the machining pitch p of the altered portion 21c adjacent in the laser beam scanning direction S and the machining offset w of the altered portion 21c adjacent in the laser beam offset direction F can be greatly increased compared to the conventional case. In addition, the processing density of the altered portion 21c, that is, the number of formed altered portions 21c can be significantly reduced. Therefore, the processing time of the altered portion 21c is further greatly shortened, and the manufacturing efficiency of the internal processed layer forming single crystal member 20 is greatly improved. Moreover, the force required for peeling can also be reduced.
また、被照射面２０ｔからのクラックＣＳ、ＣＦの深さ位置が、各クラックで略同一となっている。従って、非加工層２２の剥離面が従来に比べて大幅に平坦となっている。 Further, the depth positions of the cracks CS and CF from the irradiated surface 20t are substantially the same for each crack. Therefore, the peeling surface of the non-processed layer 22 is significantly flat compared to the conventional case.
なお、本実施形態では、クラックＣＳおよびクラックＣＦの両者を形成する例で説明したが、加工ピッチｐおよび加工オフセットｗの一方を広くしてクラックＣＳおよびクラックＣＦの一方のみを形成した場合であっても、そのクラックから剥離させることができ、これにより、変質部２１ｃの加工時間を更に短縮させることができる。 In this embodiment, the example in which both the crack CS and the crack CF are formed has been described. However, only one of the crack CS and the crack CF is formed by widening one of the processing pitch p and the processing offset w. However, it can be made to peel from the crack, and this can further shorten the processing time of the altered portion 21c.
また、本実施形態では、単結晶部材１０としてシリコンウエハＥを例に挙げて説明したが、単結晶部材１０がインゴット状であって、加工層２１を形成してレーザ光照射側の非加工層２２を剥がすことを順次繰り返してもよく、単結晶部材１０の寸法は特に限定しない。 In the present embodiment, the silicon wafer E is described as an example of the single crystal member 10. However, the single crystal member 10 has an ingot shape, and a processed layer 21 is formed to form a non-processed layer on the laser light irradiation side. Stripping 22 may be sequentially repeated, and the dimensions of the single crystal member 10 are not particularly limited.
また、本実施形態では、ビームスプリッタの機能を有する回折光学素子７２で１本のレーザ光Ｂを複数のＢＤに分割する例で説明したが、他の機能を有する回折光学素子を用いてもよく、更には回折光学素子以外の手段でレーザ光Ｂを分割することも可能である。 In this embodiment, the example in which one laser beam B is divided into a plurality of BDs by the diffractive optical element 72 having the beam splitter function has been described. However, a diffractive optical element having another function may be used. Further, the laser beam B can be divided by means other than the diffractive optical element.
＜実験例＞
本発明者は、以下の条件で実験を行い、得られた内部加工層形成単結晶部材の評価を行った。
<Experimental example>
The inventor conducted an experiment under the following conditions and evaluated the obtained internally processed layer-forming single crystal member.
加工試料 ： 単結晶Ｐ型シリコンウエハ
１）厚さ： ６２５μｍ
２）大きさ ： φ１５０ｍｍ
３）結晶方位 ：（１００）
レーザ発振器 ： ＹＡＧパルスレーザ発振器
１）波長：１０６４ｎｍ
２）モード ： シングルモード
３）パルス幅 ： １２０ｎｍ
ビームスプリッタ
１）分岐ビーム数 ： ５
加工条件 １）加工ピッチ ｐ： ２．０μｍ
ｋ： ２．０μｍ
２）加工オフセット ｗ： ７．０μｍ
３）分岐ビームパワー : 表１に示すパワー
1) Thickness: 625 μm
2) Size: φ150mm
3) Crystal orientation: (100)
Laser oscillator: YAG pulse laser oscillator
1) Wavelength: 1064 nm
2) Mode: Single mode
3) Pulse width: 120 nm
Beam splitter
1) Number of branch beams: 5
Processing conditions 1) Processing pitch p: 2.0 μm
k: 2.0 μm
2) Processing offset w: 7.0 μm
3) Branch beam power: Power shown in Table 1
加工手順および評価 ：
１）分岐ビームの焦点を試料ウエハ表面となるように集光器の高さ位置を調整する。
２）次に、その位置から集光器高さを試料ウエハ方向に８０μｍ加工させ、分岐ビーム焦点を試料ウエハ内部に移動する。
３）上記加工条件で、φ１５０ｍｍウエハ内部の１００ｍｍ×１００ｍｍの部分にレーザを照射した。
４）この試料を２個作成した。
５）１個の試料を使用して、レーザ照射部分の１辺をダイシングにより切り出し、加工層を露出させ、５０箇所の加工層の位置の差を共焦点レーザ顕微鏡（機種名：ＯＬＳ−４０００ オリンパス（株）製）により測定したところ、３μｍ以下であった。
なお、加工層位置の測定結果を表２に示す。表２では、ウエハのレーザ照射面側の表面を基準にした測定結果を示している。
６）残りの１試料からレーザ照射領域部分を、ダイシングにより切り出した。その切り出したウエハは、切り出した状態で応力を負荷させることなく加工層で２枚に分断、剥離することができた。
７）剥離したウエハ（単結晶部材部分）の表面粗さを非接触三次元測定装置（ＰＦ−６０：三鷹光器（株）製）で測定した結果、表面粗さＲａ＝２．７μｍであった。
８）剥離したウエハ（単結晶部材部分）の剥離面を走査型電子顕微鏡にて観察したところ、分岐ビームによる加工痕とクラックの伝播と推察される状態が見られた。
1) Adjust the height position of the condenser so that the focus of the branched beam is on the sample wafer surface.
2) Next, the height of the collector is processed from the position toward the sample wafer by 80 μm, and the branch beam focus is moved into the sample wafer.
3) A laser was irradiated on a 100 mm × 100 mm portion inside a φ150 mm wafer under the above processing conditions.
4) Two samples were prepared.
5) Using one sample, cut out one side of the laser irradiated part by dicing, expose the processed layer, and determine the difference in position of the 50 processed layers using a confocal laser microscope (model name: OLS-4000 Olympus) (Measurement by Co., Ltd.) and found to be 3 μm or less.
The measurement results of the processed layer position are shown in Table 2. Table 2 shows the measurement results based on the laser irradiation surface side of the wafer.
6) The laser irradiation area portion was cut out from the remaining one sample by dicing. The cut-out wafer could be cut into two pieces and separated by the processed layer without applying stress in the cut-out state.
7) As a result of measuring the surface roughness of the peeled wafer (single crystal member portion) with a non-contact three-dimensional measuring device (PF-60: manufactured by Mitaka Kogyo Co., Ltd.), the surface roughness Ra = 2.7 μm. It was.
8) When the peeled surface of the peeled wafer (single crystal member portion) was observed with a scanning electron microscope, a state inferred from propagation of processing marks and cracks due to the branched beam was observed.
同じ実験条件で単結晶部材１０に加工層２１を形成し、加工進行方向（レーザ走査方向Ｓ）に沿って一列に並んだ各変質部２１ｃを切断した光学顕微鏡写真図を図９に示す。図９に示すように、上記のクラックＣＳが略同一深さ位置に形成されていることが確認された。なお、レーザ光照射面側の単結晶部材部分の剥離面を図１０に示す。 FIG. 9 shows an optical micrograph of the processed layer 21 formed on the single crystal member 10 under the same experimental conditions, and the altered portions 21c arranged in a line along the processing progress direction (laser scanning direction S). As shown in FIG. 9, it was confirmed that the crack CS was formed at substantially the same depth. Note that a peeling surface of the single crystal member portion on the laser beam irradiation surface side is shown in FIG.
本発明により薄い単結晶基板を効率良く形成することができることから、薄く切り出された単結晶基板は、Ｓｉ基板（シリコン基板）であれば、太陽電池に応用可能であり、また、ＳｉＣなどであれば、ＳｉＣ系パワーデバイスなどに応用可能であり、透明エレクトロニクス分野、照明分野、ハイブリッド／電気自動車分野など幅広い分野において適用可能である。 Since a thin single crystal substrate can be efficiently formed according to the present invention, the thinly cut single crystal substrate can be applied to a solar cell as long as it is a Si substrate (silicon substrate). For example, the present invention can be applied to SiC power devices and the like, and can be applied in a wide range of fields such as transparent electronics field, lighting field, and hybrid / electric vehicle field.
１０ 単結晶部材
２０ 内部加工層形成単結晶部材
２０ｔ 被照射面
２１ 加工層
２１ｃ 変質部
２１ｓ 加工痕
２２ 非加工層（非加工部）
７２ 回折光学素子（回折光学素子、レーザ集光手段）
７３ アパーチャ（レーザ集光手段）
７４ 凸レンズ（凸レンズ、レーザ集光手段）
７８ 集光器（集光器、レーザ集光手段）
８２ 集光レンズ群
Ｂ レーザ光
ＢＤ レーザ光
ＣＦ クラック
ＣＳ クラック
Ｆ オフセット方向
Ｌ 距離（中心間距離）
Ｓ 走査方向
ｐ 加工ピッチ
ｗ 加工オフセット
10 Single crystal member 20 Internally processed layer forming single crystal member 20t Irradiated surface 21 Processed layer 21c Altered part 21s Processed mark 22 Non-processed layer (non-processed part)
72 Diffractive optical element (diffractive optical element, laser focusing means)
73 Aperture (Laser focusing means)
74 Convex lens (convex lens, laser focusing means)
78 Condenser (condenser, laser condensing means)
82 Condensing lens group B Laser light BD Laser light CF Crack CS Crack F Offset direction L Distance (distance between centers)
S Scanning direction p Processing pitch w Processing offset
Claims (6)
前記加工層の両面側にそれぞれ隣接する非加工部と、
を備え、
前記加工層には、１本のレーザ光が分割されてなる複数のレーザ光の集光によって形成され、隣接する加工痕同士が互いに一部重なって繋がることで一方向に連なってなる変質部が、レーザ光の走査方向およびオフセット方向にそれぞれ複数個配列され、
かつ、レーザ光の走査方向に隣り合う変質部同士に跨るクラック、および、レーザ光のオフセット方向に隣り合う変質部同士に跨るクラックの両方が形成されているとともに、
クラックの前記被照射面からの深さ位置が略同一深さ位置であり、
前記加工層と前記非加工層との間に連続する境界が形成されていて前記境界の全面から剥離可能になっていることを特徴とする内部加工層形成単結晶部材。 By relatively moving the single crystal member and the laser condensing means while irradiating the laser light from the irradiated surface of the single crystal member of silicon through the laser condensing means for condensing the laser light, A processed layer formed inside the single crystal member;
A non-processed part adjacent to each side of the processed layer;
With
The processed layer is formed by condensing a plurality of laser beams obtained by dividing one laser beam, and has an altered portion that is continuous in one direction by connecting adjacent processing traces partially overlapping each other. A plurality of laser beams are arranged in the scanning direction and the offset direction,
And both the cracks straddling the altered parts adjacent in the scanning direction of the laser light and the cracks straddling the altered parts adjacent in the offset direction of the laser light are formed,
The depth position from the irradiated surface of the crack is substantially the same depth position,
An internal processed layer-forming single crystal member, wherein a continuous boundary is formed between the processed layer and the non-processed layer and can be peeled from the entire surface of the boundary.
１本のレーザ光が入射すると、同一平面内を進み、かつ、隣り合うレーザ光同士のなす角度が均等となるような複数のレーザ光に分割して出射する、ビームスプリッタ手段を前記レーザ集光手段に設け、
該ビームスプリッタ手段で分割された複数のレーザ光を前記単結晶部材に照射してそれぞれ前記単結晶部材内部に集光することで、複数のレーザ光により、隣接する加工痕同士が互いに一部重なって繋がることで一方向に連なってなる変質部を配列するように形成していくとともに、前記変質部を、レーザ光の走査方向に隣り合う変質部同士に跨るクラック、および、レーザ光のオフセット方向に隣り合う変質部同士に跨るクラックの両方が生じるとともにクラックの前記被照射面からの深さ位置が略同一深さ位置となるように形成していくことで、
前記加工層と前記非加工層との間に連続する境界が形成されて前記境界の全面から剥離可能にしたことを特徴とする内部加工層形成単結晶部材の製造方法。 By relatively moving the single crystal member and the laser condensing means while irradiating the laser light from the irradiated surface of the single crystal member of silicon through the laser condensing means for condensing the laser light, A method for producing an internally processed layer forming single crystal member, wherein a processed layer is formed inside the single crystal member and the single crystal member is used as an internally processed layer forming single crystal member,
When one laser beam is incident, the beam condensing unit emits the laser beam by dividing the laser beam into a plurality of laser beams that travel in the same plane and have equal angles between adjacent laser beams. Provided in the means,
By irradiating the single crystal member with a plurality of laser beams divided by the beam splitter means and condensing each inside the single crystal member, adjacent processing traces partially overlap each other by the plurality of laser beams. In this way, the altered portions that are connected in one direction by being connected are formed so as to be arranged, and the altered portion is divided into cracks straddling the altered portions adjacent to each other in the scanning direction of the laser beam, and the offset direction of the laser beam. By forming so that both the cracks straddling the deteriorated parts adjacent to each other occur and the depth position of the crack from the irradiated surface is substantially the same depth position,
A method for producing an internally processed layer-forming single crystal member, wherein a continuous boundary is formed between the processed layer and the non-processed layer so as to be peelable from the entire surface of the boundary.
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