JP3194822B2 - Manufacturing method of composite substrate material - Google Patents
Manufacturing method of composite substrate materialInfo
- Publication number
- JP3194822B2 JP3194822B2 JP22765093A JP22765093A JP3194822B2 JP 3194822 B2 JP3194822 B2 JP 3194822B2 JP 22765093 A JP22765093 A JP 22765093A JP 22765093 A JP22765093 A JP 22765093A JP 3194822 B2 JP3194822 B2 JP 3194822B2
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- silicon
- thermal expansion
- bonding
- mirror
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Description
【０００１】[0001]
【産業上の利用分野】本発明は複合基板材料の製造方
法、特に反りのない複合基板材料の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite substrate material, and more particularly to a method for producing a composite substrate material having no warp.
【０００２】[0002]
【従来の技術】一般に異なる性質をもった材料の積層構
造を有する基板は、現在様々な分野で利用されており、
このような基板を得る際には、化学的あるいは物理的方
法を利用した様々な薄膜形成法が用いられている。しか
し、それに代わる方法として、近年、ウエハボンディン
グと呼ばれる技術が注目を集めている。この技術は、単
結晶あるいは多結晶のウエハ表面を鏡面仕上げし、鏡面
同士をその界面にゴミや有機物などが存在しないように
清浄にした後、清浄な雰囲気中で接触させた状態で、か
つ加熱することで、先に述べた薄膜形成法と同等な接合
強度をもった接合ウエハをえられるというものである。
清浄な表面同士であれば、室温でも接着がみられるが、
加熱処理を経ることで様々な後処理に耐えうる、より強
力な接合がえられる。（以後、この方法を直接接合法と
呼ぶ。）2. Description of the Related Art In general, a substrate having a laminated structure of materials having different properties is currently used in various fields.
In obtaining such a substrate, various thin film forming methods utilizing a chemical or physical method are used. However, in recent years, a technique called wafer bonding has attracted attention as an alternative method. This technology mirror-finishes the surface of a single-crystal or polycrystalline wafer, cleans the mirrors so that no dirt or organic matter is present at the interface, and then heats the wafers while keeping them in a clean atmosphere. By doing so, it is possible to obtain a bonded wafer having a bonding strength equivalent to that of the thin film forming method described above.
If the surfaces are clean, adhesion can be seen even at room temperature,
Through the heat treatment, a stronger bond that can withstand various post-treatments can be obtained. (Hereinafter, this method is called a direct joining method.)
【０００３】[0003]
【発明が解決しようとする課題】しかしながら上記の技
術は、性質の異なる、特に熱膨張率の異なる基板同士を
直接接合する際、先に述べた加熱の過程を経ることによ
り、接合した基板間の熱膨張率差に起因した反りが生ず
るという問題を有していた。さらに、この反りのため
に、直接接合ウエハ上に電極パターン形成したり、微細
加工を行う際に、広範囲にわたって精度のよい加工を行
うことができず、フォトリソグラフィーに代表されるよ
うな微細パターン形成技術を用いる際の妨げになってい
た。However, when the above techniques are directly joined to substrates having different properties, especially different thermal expansion coefficients, the above-mentioned heating process is performed to thereby achieve the bonding between the joined substrates. There is a problem that warpage due to a difference in thermal expansion coefficient occurs. Further, due to this warpage, when forming an electrode pattern directly on a bonded wafer or performing fine processing, accurate processing cannot be performed over a wide range. It hindered the use of technology.
【０００４】さらに、一方の基板あるいは両方の基板を
機械的に研磨し単結晶の薄膜層を得る際には、この反り
のために均一な薄板化が困難となり、膜質は劣るが一様
な膜厚がえられる従来の薄膜形成技術に対しての優位性
を生かしきれないでいた。Further, when one or both substrates are mechanically polished to obtain a single-crystal thin film layer, it is difficult to make a uniform thin film due to the warpage. The advantage over the conventional thin film forming technology that can increase the thickness cannot be fully utilized.
【０００５】本発明は、上記従来の問題点を解決するも
のであり、熱膨張率の異なる基板同士を直接接合した際
にも、反りのない接合ウエハをえるための製造方法を提
供することを目的とするものである。An object of the present invention is to solve the above-mentioned conventional problems and to provide a manufacturing method for obtaining a bonded wafer without warping even when substrates having different coefficients of thermal expansion are directly bonded to each other. It is the purpose.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に、本発明は、両面が鏡面研磨された第１の基板の一方
の面に、前記第１の基板と異なる熱膨張率を有し、少な
くとも一方の面が鏡面研磨された第２の基板が鏡面同士
が向かい合うように密着され、前記第１の基板のもう一
方の面に、前記第２の基板とほぼ同じ熱膨張率を有する
材料からなり、少なくとも一方の面が鏡面研磨された第
３の基板が同じく鏡面同士が向かい合うように密着され
た後、加熱し、互いを強固に直接接合するものである。In order to achieve the above object, the present invention provides a first substrate having mirror-polished surfaces on both sides, wherein one surface of the first substrate has a different coefficient of thermal expansion from that of the first substrate. A second substrate having at least one surface mirror-polished is adhered so that the mirror surfaces face each other, and has a thermal expansion coefficient substantially equal to that of the second substrate on the other surface of the first substrate. After the third substrate, whose at least one surface is mirror-polished, is closely adhered so that the mirror surfaces face each other, the third substrate is heated and strongly directly joined to each other.
【０００７】[0007]
【作用】上記手段のように、熱膨張率の異なる基板同士
を接合する際に、熱膨張率の違いにより生じる基板の反
りを、一つの基板をほぼ同じ熱膨張率を有する２枚の基
板でサンドイッチして密着し、熱処理をすることで相殺
し、中間にはさまれた基板がいかなる熱膨張率を有して
いても反りのない接合基板がえられることとなる。When the substrates having different coefficients of thermal expansion are joined to each other as described above, the warpage of the substrates caused by the difference in the coefficient of thermal expansion is reduced by using two substrates having substantially the same coefficient of thermal expansion. The heat treatment is canceled out by sandwiching and adhering to each other, so that a bonded substrate free from warping can be obtained regardless of the coefficient of thermal expansion of the substrate sandwiched in the middle.
【０００８】[0008]
（実施例１）図１（ａ）〜（ｂ）は本実施例の工程を示
す側面図である。本実施例においては、接合する基板と
して図１（ａ）に示すように、１枚の１０ｍｍ角、３０
ＭＨｚ振動子用ＡＴｃｕｔ水晶板１１と、２枚の１０ｍ
ｍ角、０．２５ｍｍ厚の基板用ソーダ石灰ガラス板１２
を用いた。なお、これらの基板、すなわち水晶板１１、
ガラス板１２の密着されるべき面は鏡面研磨されてい
る。(Embodiment 1) FIGS. 1A and 1B are side views showing the steps of this embodiment. In the present embodiment, as shown in FIG.
ATcut quartz plate 11 for MHz oscillator and two 10m
Soda-lime glass plate 12 for m square, 0.25 mm thick substrate
Was used. In addition, these substrates, that is, the quartz plate 11,
The surface of the glass plate 12 to be adhered is mirror-polished.
【０００９】これらの基板の鏡面に研磨された接合面
を、半導体分野で用いられている精密洗浄技術を用い
て、粒子や有機物が存在しないように清浄化し、クリー
ンルーム内の清浄な雰囲気中で、接合面の間に塵や埃が
はいらないように接触させて密着することで図１（ｂ）
に示すように一体化する。The mirror-polished bonding surfaces of these substrates are cleaned using a precision cleaning technique used in the field of semiconductors so that no particles or organic substances are present, and are cleaned in a clean atmosphere in a clean room. By contacting and adhering so that dust and dust do not enter between the joining surfaces, FIG. 1 (b)
Integrated as shown in FIG.
【００１０】このままでもこれらの基板間の接合強度
は、引っ張り強度にして２０〜３０kg/cm2程度の接着強
度を示すが、この段階での接着力は、接着界面に存在す
るＯＨ基同士の水素結合によるものであり、水分がその
界面に浸透すると簡単に剥がれてしまう。しかし、この
基板に熱処理を加えることにより、接着界面に脱水反応
が生じ、水素結合が酸素を介した共有結合に置き変わ
り、化学的、物理的に安定で強固な直接接合が接着剤を
用いることなく達成される。この段階での接着強度は、
引っ張り強度にして１００kg/cm2以上の値を示し、水分
や酸に浸しても剥がれることのない安定な接合となる。The bonding strength between these substrates shows a bonding strength of about 20 to 30 kg / cm 2 in tensile strength as it is, but the bonding strength at this stage is due to the hydrogen of OH groups existing at the bonding interface. This is due to bonding, and is easily peeled off when moisture permeates the interface. However, when heat treatment is applied to this substrate, a dehydration reaction occurs at the bonding interface, hydrogen bonds are replaced by covalent bonds via oxygen, and chemically and physically stable and strong direct bonding uses an adhesive. Achieved without. The adhesive strength at this stage is
It shows a value of 100 kg / cm 2 or more in terms of tensile strength, and is a stable joint that does not peel off even when immersed in moisture or acid.
【００１１】そこで、上に述べたような安定な接合をえ
るために、図１（ｂ）に示したような基板に電気炉中で
４００℃、１時間の熱処理を加えることで、図１（ｃ）
に示すような水晶板１１をガラス板１２ではさみこんだ
サンドイッチ構造をもち、強固で安定な接合をもつ反り
のない複合基板材料がえられる。両接合界面の接合強度
は、どちらも１００kg／cm2以上で強度上の問題はな
く、また、基板の反りを表面粗さ計で測定した結果、反
りの量は基板の加工精度による基板そのものの反りの範
囲内で、熱処理による新たな反りは観察されなかった。Therefore, in order to obtain the above-mentioned stable bonding, the substrate as shown in FIG. c)
As shown in (1), a composite substrate material having a sandwich structure in which a quartz plate 11 is sandwiched between glass plates 12 and having strong and stable bonding and having no warpage can be obtained. The bonding strength at both bonding interfaces is 100 kg / cm 2 or more, and there is no problem in strength. Also, as a result of measuring the warpage of the substrate with a surface roughness meter, the amount of warpage is determined by the processing accuracy of the substrate itself. No new warping due to the heat treatment was observed within the range of the warping.
【００１２】ところで水晶は、二軸性の結晶であり、そ
の結晶軸によりその熱膨張係数が異なる。たとえば、こ
の組合せにおいて典型的な熱処理温度である４００℃に
おいて、ａ軸と呼ばれる軸に平行な方向には、１８５×
１０-7／℃、ｃ軸と呼ばれる軸に平行な方向には、１０
７×１０-7／℃という値をもつ。なお、ａ軸とｃ軸は互
いに直行している。ＡＴｃｕｔとは、水晶単結晶のｃ軸
に対してある角度をもってカットされている水晶板であ
り、本実施例で用いた１０ｍｍ角の水晶板１１において
その熱膨張率は、４００℃において、水晶板１１の互い
に平行な辺に水平の方向にそれぞれ１８６×１０-7／
℃、１３２×１０-7／℃の値をもつ。Quartz is a biaxial crystal, and its thermal expansion coefficient differs depending on its crystal axis. For example, at 400 ° C., which is a typical heat treatment temperature in this combination, 185 × in a direction parallel to an axis called an a-axis.
10 −7 / ° C., in the direction parallel to the axis called the c-axis, 10
It has a value of 7 × 10 −7 / ° C. The a-axis and the c-axis are perpendicular to each other. ATcut is a quartz plate cut at a certain angle with respect to the c-axis of the quartz single crystal. The 10 mm square quartz plate 11 used in this embodiment has a coefficient of thermal expansion at 400 ° C. 186 × 10 −7 /
° C, 132 × 10 -7 / ° C.
【００１３】一方、本実施例で用いたソーダ石灰ガラス
板１２は、等方的な熱膨張率を持ち、その値は、８７×
１０-7／℃である。この熱膨張率の違いから、サンドイ
ッチ構造を用いることなく前記水晶板１１と前記ガラス
板１２のみを直接接合したものでは、熱処理後の接合基
板平面上で互いに垂直方向に異なる反りを生じてしま
う。これは、ガラスと水晶の熱膨張率が異なるためであ
り、特に水晶のような二軸性の結晶の場合、両基板の熱
膨張率をあわせるのは難しく、本方法を用いない限り、
反りのない基板をえることは困難である。On the other hand, the soda-lime glass plate 12 used in this embodiment has an isotropic coefficient of thermal expansion, and its value is 87 ×
10 −7 / ° C. Due to this difference in the coefficient of thermal expansion, if the quartz plate 11 and the glass plate 12 alone are directly joined without using a sandwich structure, different warpages occur in the vertical direction on the joint substrate plane after the heat treatment. This is because the thermal expansion coefficients of glass and quartz are different, especially in the case of a biaxial crystal such as quartz, it is difficult to match the thermal expansion coefficients of both substrates, and unless this method is used,
It is difficult to obtain a substrate without warpage.
【００１４】上記の水晶板がガラス板によってサンドイ
ッチされた構造をもつ直接接合基板をもちいて水晶振動
子を作製する際の、一実施例を図面を参照して説明す
る。図２（ａ）〜（ｅ）は水晶振動子の製造工程の断面
図を示している。An embodiment of manufacturing a crystal unit using a direct bonding substrate having a structure in which the above-mentioned quartz plate is sandwiched by glass plates will be described with reference to the drawings. 2 (a) to 2 (e) are cross-sectional views showing the steps of manufacturing a crystal resonator.
【００１５】図２（ａ）に示すように、水晶板２１がガ
ラス板２２によってサンドイッチされた構造をもつ反り
のない直接接合基板に、図２（ｂ）に示すように、開口
部を設けるための部分を除いてマスク２３で覆う。その
後、両面から弗酸を含むエッチング液でエッチングし、
図２（ｃ）に示すように、水晶板２１の両側に開口部２
４を形成する。この工程で残るガラス部分は水晶板２１
の保持の役割を果たす。なお、エッチング液に対する水
晶のエッチング速度は、ガラスに比べて遅いため、水晶
部分がエッチストップとして働き、有機溶剤を用いてマ
スク２３を取り去り図２（ｄ）に示すような構造がえら
れる。そして最後に、水晶板２１をはさんで一対の励振
電極２５を形成することで図２（ｅ）に示すような水晶
振動子の基本的構造がえられる。As shown in FIG. 2A, a direct bonding substrate having a structure in which a quartz plate 21 is sandwiched between glass plates 22 and having no warp is provided with an opening as shown in FIG. 2B. Is covered with the mask 23 except for the portion of After that, it is etched from both sides with an etching solution containing hydrofluoric acid,
As shown in FIG. 2C, openings 2 are provided on both sides of the quartz plate 21.
4 is formed. The glass part remaining in this step is a quartz plate 21
Plays the role of retention. Since the etching rate of the quartz with respect to the etchant is lower than that of the glass, the quartz portion functions as an etch stop, and the mask 23 is removed by using an organic solvent to obtain a structure as shown in FIG. 2D. Finally, by forming a pair of excitation electrodes 25 with the crystal plate 21 interposed therebetween, a basic structure of the crystal resonator as shown in FIG. 2E is obtained.
【００１６】また、この基板には反りがないため、マス
ク２３の形成が半導体分野で用いられているような微細
パターン形成技術を用いて行えるので、超小型の水晶振
動子が精密に作製できる。Further, since the substrate has no warp, the mask 23 can be formed using a fine pattern forming technique used in the field of semiconductors, so that a very small crystal resonator can be manufactured accurately.
【００１７】なお、本実施例では、効果をわかりやすく
するために、水晶と熱膨張率の異なるガラス板を用いた
が、熱膨張率が水晶と近いガラスを選択することで、接
合面に生ずる歪が非常に少ない上、反りの無い水晶−ガ
ラス接合基板がえられることは当然である。In this embodiment, a glass plate having a different coefficient of thermal expansion from that of quartz is used in order to make the effect easy to understand. Naturally, a quartz-glass bonded substrate having very little distortion and no warpage can be obtained.
【００１８】（実施例２）本実施例では、実施例１と同
様に１０ｍｍ角の３０ＭＨｚ振動子用ＡＴｃｕｔ水晶板
と１０ｍｍ角、０．２５ｍｍ厚の基板用ソーダ石灰ガラ
ス板を用いた。図３（ａ）〜（ｄ）は、本実施例の工程
を示す側面図である。なお、洗浄方法、接合条件も実施
例１と同じである。異なるのは図１（ａ）に示すよう
に、ガラス板３１を水晶板３２と、少なくともガラス板
３１に接合される側の面にシリコン膜３４を形成した水
晶板３３ではさみこむ構造を有する点である。なお、こ
れらの基板の接合面は鏡面研磨されている。Example 2 In this example, a 10 mm square ATcut quartz plate for a 30 MHz vibrator and a 10 mm square, 0.25 mm thick soda-lime glass plate for a substrate were used as in the first embodiment. 3A to 3D are side views showing the steps of this embodiment. The cleaning method and the bonding conditions are the same as in the first embodiment. The difference is that, as shown in FIG. 1A, the glass plate 31 has a structure in which the glass plate 31 is sandwiched between a quartz plate 32 and a quartz plate 33 having a silicon film 34 formed on at least a surface joined to the glass plate 31. is there. The bonding surfaces of these substrates are mirror-polished.
【００１９】これらの基板３枚の接合面を、精密洗浄し
た後、鏡面同士が向かい合うようにして密着し、さらに
接合を強固にするために、電気炉で４００℃、１時間の
熱処理を行った。その結果、図３（ｂ）に示すような、
反りのない直接接合複合基板材料がえられた。この場
合、シリコン膜３４は数千Ａと、非常に薄く、単結晶の
ものほど緻密でないため、熱膨張率が異なってもバッフ
ァ層的な役割を果たし、基板に反りを生じさせるような
ことはない。After precision cleaning of the bonding surfaces of these three substrates, they were closely adhered so that the mirror surfaces faced each other, and heat treatment was performed at 400 ° C. for 1 hour in an electric furnace to further strengthen the bonding. . As a result, as shown in FIG.
A directly bonded composite substrate material without warpage was obtained. In this case, the silicon film 34 is very thin, several thousand A, and is not as dense as that of a single crystal. Therefore, the silicon film 34 functions as a buffer layer even if the coefficient of thermal expansion is different, and it is difficult for the substrate to warp. Absent.
【００２０】この基板を、図３（ｃ）に示すように両面
研磨し、水晶板３２が所期の厚さになるように研磨す
る。このとき研磨中に接合面から分離してしまうような
ことはなく、充分研磨工程に耐え得るだけの接着強度が
えられている。また、この基板には、反りがないため水
晶部分は一様に研磨され、５μｍ以下まで薄くできる。
その後、図３（ｄ）に示すように、シリコン膜３４の部
分を選択的にエッチングするようなエッチャント、たと
えばヒドラジンを用いて、一方の水晶板３３をリフトオ
フする。This substrate is polished on both sides as shown in FIG. 3C so that the quartz plate 32 has the desired thickness. At this time, there is no separation from the bonding surface during polishing, and an adhesive strength enough to withstand the polishing step is obtained. In addition, since the substrate has no warp, the crystal portion is uniformly polished and can be thinned to 5 μm or less.
Thereafter, as shown in FIG. 3D, one of the quartz plates 33 is lifted off using an etchant for selectively etching the silicon film 34, for example, hydrazine.
【００２１】このようにして５μｍ以下の水晶板３２が
ガラス板３１に強固に直接接合された複合基板材料がえ
られる。また、この基板には反りがなく、半導体技術で
用いられる微細パターン形成技術を用いて、精密に加工
することができる。In this way, a composite substrate material in which the quartz plate 32 having a size of 5 μm or less is firmly and directly bonded to the glass plate 31 is obtained. Also, this substrate has no warpage and can be precisely processed by using a fine pattern forming technique used in semiconductor technology.
【００２２】上記の構造をもつ直接接合基板をもちいて
水晶振動子を作製する際の、一実施例を図面を参照して
説明する。図４（ａ）〜（ｅ）は水晶振動子の製造工程
の断面図を示している。An example of manufacturing a crystal unit using the direct bonding substrate having the above structure will be described with reference to the drawings. 4 (a) to 4 (e) are cross-sectional views showing the steps of manufacturing the crystal resonator.
【００２３】図４（ａ）に示すような、５μｍ以下と非
常に薄い水晶板４１がガラス板４２に強固に直接接合さ
れた複合基板材表面に、図４（ｂ）に示すようなガラス
板４２の一部分に開口部を設けるためのマスク４３を形
成する。この基板をガラス側から弗酸を含むエッチング
液でエッチングすることで図４（ｃ）に示すような開口
部４４を形成する。この工程で残るガラス部分は水晶板
４１の保持の役割を果たす。なお、エッチング液に対す
る水晶のエッチング速度は、ガラスに比べて遅いため、
水晶部分がエッチストップとして働き、有機溶剤でマス
ク４３を取り去ることで図４（ｄ）に示すような構造が
容易にえられる。そして最後に、水晶板４１をはさんで
一対の励振電極４５を形成することで図４（ｅ）に示す
ような水晶振動子の基本的構成が完成する。As shown in FIG. 4 (a), a crystal plate 41 as shown in FIG. 4 (b) is provided on the surface of a composite substrate material in which a very thin quartz plate 41 having a thickness of 5 μm or less is firmly bonded directly to a glass plate 42. A mask 43 for forming an opening in a part of 42 is formed. This substrate is etched from the glass side with an etching solution containing hydrofluoric acid to form an opening 44 as shown in FIG. The glass portion remaining in this step plays a role of holding the quartz plate 41. Since the etching rate of quartz with respect to the etchant is slower than that of glass,
The crystal portion functions as an etch stop, and the structure shown in FIG. 4D can be easily obtained by removing the mask 43 with an organic solvent. Finally, by forming a pair of excitation electrodes 45 with the crystal plate 41 interposed therebetween, the basic configuration of the crystal resonator as shown in FIG. 4E is completed.
【００２４】このような水晶振動子は、水晶板４１の厚
さが本実施例の工程を経ることで非常に薄くできるので
水晶振動子の超高周波化が可能になる。さらに、水晶板
４１の保持が直接接合で実現され、接着剤を用いる必要
がないので特性が安定する。In such a crystal resonator, the thickness of the crystal plate 41 can be made extremely thin through the steps of the present embodiment, so that a very high frequency of the crystal resonator can be achieved. Further, the holding of the quartz plate 41 is realized by direct bonding, and there is no need to use an adhesive, so that the characteristics are stabilized.
【００２５】なお、本実施例では、このような基板をえ
るための方法として水晶板３３の接合面にシリコン膜３
４を形成したが、ガラス板側の接合面あるいは両方にシ
リコン膜を形成しても同様の効果がえられることは言う
までもない。 （実施例３）実施例２で述べたように、接合面に薄膜層
を形成することで、基板材料のリフトオフが可能にな
り、さらに直接接合できないもの同士の接合が可能にな
る。In this embodiment, as a method for obtaining such a substrate, the silicon film 3
4 was formed, but it goes without saying that the same effect can be obtained by forming a silicon film on the bonding surface on the glass plate side or on both sides. (Embodiment 3) As described in the embodiment 2, by forming the thin film layer on the bonding surface, the lift-off of the substrate material becomes possible, and further, the bonding between those which cannot be directly bonded becomes possible.
【００２６】また、直接接合では、接合される面の平坦
度が非常に重要であるが、この平坦度を得るためにも前
記薄膜層を利用することができる。次に、その実施例を
示す。図５（ａ）〜（ｃ）は、本実施例の工程を示す側
面図である。In the case of direct bonding, the flatness of the surfaces to be bonded is very important. In order to obtain this flatness, the thin film layer can be used. Next, an embodiment thereof will be described. FIGS. 5A to 5C are side views showing the steps of this embodiment.
【００２７】図５（ａ）に示すように、シリコン基板５
１を２枚の砒化ガリウム基板５２ではさみこむ構造を形
成する。なお、はさみこまれるシリコン基板５１の両面
は鏡面研磨されているが、砒化ガリウム基板５２の両面
は必ずしも研磨されている必要はない。As shown in FIG. 5A, the silicon substrate 5
1 is sandwiched between two gallium arsenide substrates 52 to form a structure. Although both surfaces of the silicon substrate 51 to be sandwiched are mirror-polished, both surfaces of the gallium arsenide substrate 52 need not necessarily be polished.
【００２８】次に、図５（ｂ）に示すように砒化ガリウ
ム基板５２の接合面側に酸化珪素膜５３を形成する。そ
の後、酸化珪素膜５３表面を鏡面研磨し、表面粗さが５
００ｎｍ以下になるように平坦化する。Next, as shown in FIG. 5B, a silicon oxide film 53 is formed on the bonding surface side of the gallium arsenide substrate 52. Thereafter, the surface of the silicon oxide film 53 is mirror-polished to a surface roughness of 5
It is flattened to have a thickness of not more than 00 nm.
【００２９】さらに、鏡面に研磨された酸化珪素膜５３
とシリコン基板５１表面を上に述べてきた方法と同様の
方法で洗浄し、密着する。そして最後に電気炉中で３０
０℃、１時間の熱処理を加えることにより、図５（ｃ）
に示すような反りの無いシリコン砒化ガリウム複合基板
材料がえられる。酸化珪素膜５３は、数千Ａ以下と薄
く、単結晶のものほど緻密でないため、バッファ層とし
て働き、砒化ガリウム基板５２およびシリコン基板５１
に歪を生じないため、単結晶の特性に影響を与えること
が少ない。また、酸化珪素膜５３は、広い波長範囲にお
いて透明であるため、この基板を光素子用基板として用
いるときにも光の通過を妨げることが無い。そのため、
この基板は、光素子用複合基板として実用化することが
できる。Further, a mirror-polished silicon oxide film 53
Then, the surface of the silicon substrate 51 is cleaned and adhered by the same method as described above. And finally 30 in the electric furnace
By applying a heat treatment at 0 ° C. for one hour, FIG.
As a result, a silicon gallium arsenide composite substrate material having no warp as shown in FIG. Since the silicon oxide film 53 is as thin as several thousand A or less and not as dense as a single crystal film, it functions as a buffer layer, and serves as a gallium arsenide substrate 52 and a silicon substrate 51.
Since no distortion is caused in the single crystal, the characteristics of the single crystal are hardly affected. Further, since the silicon oxide film 53 is transparent in a wide wavelength range, it does not hinder the passage of light even when this substrate is used as a substrate for an optical element. for that reason,
This substrate can be put to practical use as a composite substrate for optical devices.
【００３０】さらに、酸化珪素膜５３を形成した後に、
酸化珪素膜５３のみを研磨することで研磨の際に生ずる
機械的な歪が基板の特性に影響を及ぼさないため、特性
のよい複合基板材料がえられる。Further, after forming the silicon oxide film 53,
By polishing only the silicon oxide film 53, the mechanical distortion generated during the polishing does not affect the characteristics of the substrate, so that a composite substrate material having good characteristics can be obtained.
【００３１】（実施例４）実施例４は実施例３とほぼ同
様であり、異なるのは接合の際の一方の中間層として酸
化珪素膜でなく、窒化珪素膜を用いる点である。次に、
その実施例を示す。図６は、本実施例の工程を示す側面
図である。Embodiment 4 Embodiment 4 is almost the same as Embodiment 3, except that a silicon nitride film is used instead of a silicon oxide film as one intermediate layer at the time of bonding. next,
An example will be described. FIG. 6 is a side view showing the steps of this embodiment.
【００３２】図６（ａ）に示すように、シリコン基板６
１を砒化ガリウム基板６２および６３ではさみこむ構造
を形成する。なお、はさみこまれるシリコン基板６１の
両面は鏡面研磨されているが、砒化ガリウム基板６２お
よび６３の両面は必ずしも研磨されている必要はない。
次に、図６（ｂ）に示すように砒化ガリウム基板６２
の接合面側に酸化珪素膜６４を形成し、もう一方の砒化
ガリウム基板６３の接合面側には窒化珪素膜６５を形成
する。As shown in FIG. 6A, the silicon substrate 6
1 is formed between the gallium arsenide substrates 62 and 63. Although both surfaces of the silicon substrate 61 to be sandwiched are mirror-polished, both surfaces of the gallium arsenide substrates 62 and 63 are not necessarily polished.
Next, as shown in FIG.
A silicon oxide film 64 is formed on the bonding surface side of the substrate, and a silicon nitride film 65 is formed on the bonding surface side of the other gallium arsenide substrate 63.
【００３３】その上で、酸化珪素膜６４および窒化珪素
膜６５の表面を鏡面に研磨し、接合面を清浄にして、鏡
面同士を接触させて密着する。そして最後に電気炉中で
３００℃、１時間の熱処理を加えることにより、図６
（ｃ）に示すような反りの無いシリコン砒化ガリウム複
合基板材料がえられる。酸化珪素膜６４および窒化珪素
膜６５は、数千Ａ以下と薄く、単結晶のものほど緻密で
ないためバッファ層として働き、砒化ガリウム基板６
２、６３およびシリコン基板６１に歪を生じないため、
単結晶の特性に影響を与えることが少ない。また、酸化
珪素膜６４は、広い波長範囲において透明であるため、
この基板を光素子用基板として用いるときにも光の通過
を妨げることが無い。そのため、この基板は、光素子用
複合基板として実用化することができる。After that, the surfaces of the silicon oxide film 64 and the silicon nitride film 65 are polished to a mirror surface, the bonding surface is cleaned, and the mirror surfaces are brought into close contact with each other. Finally, a heat treatment at 300 ° C. for one hour is performed in an electric furnace to obtain the heat treatment shown in FIG.
A warp-free silicon gallium arsenide composite substrate material as shown in (c) is obtained. The silicon oxide film 64 and the silicon nitride film 65 are as thin as several thousand A or less, and are not as dense as a single crystal film, so that they function as buffer layers, and the gallium arsenide substrate 6
2, 63 and the silicon substrate 61 do not cause distortion.
It hardly affects the characteristics of the single crystal. Further, since the silicon oxide film 64 is transparent in a wide wavelength range,
Even when this substrate is used as an optical element substrate, it does not hinder the passage of light. Therefore, this substrate can be put to practical use as a composite substrate for optical elements.
【００３４】さらに、酸化珪素膜６４および窒化珪素膜
６５を形成した後に、薄膜層のみを研磨することで研磨
の際に生ずる機械的な歪が基板の特性に影響を及ぼさな
いため、特性のよい複合基板材料がえられる。また、接
合のためのバッファ層に酸化珪素と窒化珪素という異な
る性質の材料を用いているため、エッチング液を適当に
選ぶことで、いずれかの基板を選択的にリフトオフでき
るため、２種の異種材料による反りのない複合基板材料
が容易にえられる。Further, after the silicon oxide film 64 and the silicon nitride film 65 are formed, only the thin film layer is polished, so that the mechanical strain generated at the time of polishing does not affect the characteristics of the substrate. A composite substrate material is obtained. In addition, since different materials such as silicon oxide and silicon nitride are used for the buffer layer for bonding, one of the substrates can be selectively lifted off by appropriately selecting an etching solution. A composite substrate material without warpage due to the material can be easily obtained.
【００３５】なお、接合できる材料は上記のものに限る
わけではなく、接合表面が鏡面であれば材料を問わな
い。また、接合できない材料同士であっても、薄膜状の
バッファ層を介することで接合が可能になる。そのた
め、自由な組合せの複合基板材料が本方法を用いてえら
れる。The materials that can be joined are not limited to those described above, and any material can be used as long as the joining surface is a mirror surface. Further, even materials that cannot be joined can be joined via the thin-film buffer layer. Thus, any combination of composite substrate materials can be obtained using the present method.
【００３６】（実施例５）実施例４で、バッファ層を介
して接合することで、サンドイッチ構造をもった複合基
板材料から容易に異種材料からなる二層複合基板材料が
えられることを述べた。本実施例では、接合の際にバッ
ファ層を用いることなく実施例４と同様の二層複合基板
材料をえる方法について図を用いて説明する。図７は本
実施例の工程を示す側面図である。Example 5 In Example 4, it was described that a two-layer composite substrate material composed of different materials can be easily obtained from a composite substrate material having a sandwich structure by bonding via a buffer layer. . In the present embodiment, a method for obtaining the same two-layer composite substrate material as in Embodiment 4 without using a buffer layer at the time of bonding will be described with reference to the drawings. FIG. 7 is a side view showing the steps of this embodiment.
【００３７】図７（ａ）に示すように、インジウムリン
基板７１をガラス基板７３とシリコン基板７２ではさみ
こむ構造を形成する。ガラス基板７３には、熱膨張率が
３２×１０-7／℃のほう珪酸ガラスを用いた。シリコン
の熱膨張率は３５×１０-7／℃であり、インジウムリン
の熱膨張率は、４５×１０-7／℃である。シリコンとほ
う珪酸ガラスの熱膨張率差は、インジウムリンとの熱膨
張率差に比べて非常に小さい。なお、これらの基板の接
合面は鏡面研磨されている。As shown in FIG. 7A, a structure is formed in which an indium phosphorus substrate 71 is sandwiched between a glass substrate 73 and a silicon substrate 72. As the glass substrate 73, borosilicate glass having a coefficient of thermal expansion of 32 × 10 −7 / ° C. was used. The coefficient of thermal expansion of silicon is 35 × 10 −7 / ° C., and the coefficient of thermal expansion of indium phosphorus is 45 × 10 −7 / ° C. The difference in thermal expansion coefficient between silicon and borosilicate glass is much smaller than the difference in thermal expansion coefficient between indium phosphide and silicon. The bonding surfaces of these substrates are mirror-polished.
【００３８】次に、図７（ｂ）に示すように、インジウ
ムリン基板７１とガラス基板７３およびシリコン基板７
２の接合面を清浄にし、サンドイッチ構造を形成して一
体化した後、電気炉中で３００℃、１時間の熱処理を加
えることにより、図７（ｃ）に示すような反りの無い複
合基板材料がえられる。このとき、はさみこむ側の両基
板間に大きな熱膨張率差が存在すると、接合基板は全体
として反りを生じてしまう。しかし、本実施例では、シ
リコン基板７２とほう珪酸ガラス基板７３の熱膨張率が
近いために、基板に反りは生じなかった。Next, as shown in FIG. 7B, the indium phosphide substrate 71, the glass substrate 73, and the silicon substrate 7
After cleaning the joint surface of No. 2 to form a sandwich structure and integrating them, a heat treatment at 300 ° C. for 1 hour was applied in an electric furnace to obtain a composite substrate material without warpage as shown in FIG. 7C. Can be obtained. At this time, if there is a large difference in the coefficient of thermal expansion between the two substrates on the sandwiching side, the bonded substrate will be warped as a whole. However, in this example, the silicon substrate 72 and the borosilicate glass substrate 73 had similar coefficients of thermal expansion, so that the substrates did not warp.
【００３９】さらに、図７（ｃ）に示すように、ガラス
部分をエッチングで取り去ることにより、シリコンとイ
ンジウムリンからなる反りのない複合基板材料が容易に
えられる。Further, as shown in FIG. 7C, by removing the glass portion by etching, a warped composite substrate material composed of silicon and indium phosphide can be easily obtained.
【００４０】また、本実施例では、インジウムリン基板
７１をはさみこむのにシリコン基板７２とシリコンに熱
膨張率の近いガラス基板７３を用いたが、これに限るも
のではなく、その他の材料においても、熱膨張率が近い
材料間に特定の材料をはさむことにより、様々な複合基
板材料がえられることは容易に考えられる。しかし、ガ
ラスはその組成により、その熱膨張率を自由に変えうる
ため熱膨張率をあわせやすく、加工も容易であるためこ
のような構造をえるためには都合がよい。In this embodiment, the silicon substrate 72 and the glass substrate 73 having a coefficient of thermal expansion close to that of silicon are used to sandwich the indium phosphide substrate 71. However, the present invention is not limited to this. It is easily conceivable that various composite substrate materials can be obtained by inserting a specific material between materials having similar thermal expansion coefficients. However, glass can be freely changed in its coefficient of thermal expansion depending on its composition, so that it is easy to adjust the coefficient of thermal expansion, and it is easy to process, so it is convenient to obtain such a structure.
【００４１】また、各実施例においての熱処理の温度
は、本実施例に挙げたものに限るわけではなく、各々の
材料特性を変化させない温度であればよいことはいうま
でもない。Further, the temperature of the heat treatment in each embodiment is not limited to the temperature described in this embodiment, and it goes without saying that the temperature may be any temperature that does not change the material properties of each material.
【００４２】[0042]
【発明の効果】以上述べたように、本発明によれば、熱
膨張率の異なるウエハを密着し、加熱して直接接合する
際の基板の反りを防止でき、接合ウエハの加工精度を大
幅に向上させることができる。また、接着に接着剤を用
いていないため様々な後工程にも充分耐え得る基板がえ
られる。さらに、接合する材料は単結晶材料であるた
め、個々の材料の結晶性がよい複合基板材料となる。As described above, according to the present invention, the wafers having different thermal expansion coefficients can be closely adhered to each other, and the substrate can be prevented from being warped when directly bonded by heating. Can be improved. Further, since no adhesive is used for bonding, a substrate which can sufficiently withstand various post-processes can be obtained. Further, since the material to be joined is a single crystal material, a composite substrate material having good crystallinity of each material is obtained.
【００４３】したがって、本発明の方法を製品に応用す
ることで、小型化が可能になり、特性が向上し、大幅な
コストダウンが図れ、実用化に大きく寄与する。Therefore, by applying the method of the present invention to products, miniaturization becomes possible, characteristics are improved, cost can be significantly reduced, and it greatly contributes to practical use.
【図１】本発明の実施例１の工程を示す側面図FIG. 1 is a side view showing the steps of Embodiment 1 of the present invention.
【図２】同実施例１でえられる接合基板より水晶振動子
を作製する際の製造工程を示す断面図FIG. 2 is a cross-sectional view showing a manufacturing process when manufacturing a crystal unit from the bonded substrate obtained in Example 1;
【図３】本発明の実施例２の工程を示す側面図FIG. 3 is a side view showing the steps of Embodiment 2 of the present invention.
【図４】同実施例２でえられる接合基板より水晶振動子
を作製する際の製造工程を示す断面図FIG. 4 is a cross-sectional view showing a manufacturing process when manufacturing a crystal resonator from the bonded substrate obtained in Example 2;
【図５】本発明の実施例３の工程を示す側面図FIG. 5 is a side view showing the steps of Embodiment 3 of the present invention.
【図６】本発明の実施例４の工程を示す側面図FIG. 6 is a side view showing the steps of Embodiment 4 of the present invention.
【図７】本発明の実施例５の工程を示す側面図FIG. 7 is a side view showing the steps of Embodiment 5 of the present invention.
１１ 水晶板 １２ ガラス板 ２１ 水晶基板 ２２ ガラス基板 ２３ マスク ２４ 開口部 ２５ 励振電極 ３１ ガラス基板 ３２ 水晶基板 ３３ シリコン膜を形成した水晶基板 ３４ シリコン膜 ４１ 水晶基板 ４２ ガラス基板 ４３ マスク ４４ 開口部 ４５ 励振電極 ５１ シリコン基板 ５２ 砒化ガリウム基板 ５３ 酸化珪素膜 ６１ シリコン基板 ６２ 砒化ガリウム基板１ ６３ 砒化ガリウム基板２ ６４ 酸化珪素膜 ６５ 窒化珪素膜 ７１ インジウムリン基板 DESCRIPTION OF SYMBOLS 11 Quartz plate 12 Glass plate 21 Quartz substrate 22 Glass substrate 23 Mask 24 Opening 25 Excitation electrode 31 Glass substrate 32 Quartz substrate 33 Quartz substrate with silicon film formed 34 Silicon film 41 Quartz substrate 42 Glass substrate 43 Mask 44 Opening 45 Excitation Electrode 51 Silicon substrate 52 Gallium arsenide substrate 53 Silicon oxide film 61 Silicon substrate 62 Gallium arsenide substrate 1 63 Gallium arsenide substrate 2 64 Silicon oxide film 65 Silicon nitride film 71 Indium phosphorus substrate
───────────────────────────────────────────────────── フロントページの続き (72)発明者 田口 豊 大阪府門真市大字門真1006番地 松下電 器産業株式会社内 (72)発明者 江田 和生 大阪府門真市大字門真1006番地 松下電 器産業株式会社内 (56)参考文献 特開 平３−78732（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01L 21/02 B32B 18/00 C04B 37/04 H01L 41/22 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yutaka Taguchi 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-house (56) References JP-A-3-78732 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) H01L 21/02 B32B 18/00 C04B 37/04 H01L 41/22
Claims (6)
の面に、前記第１の基板と異なる熱膨張率を有し、少な
くとも一方の面が鏡面研磨された第２の基板を鏡面同士
が向かい合うように密着し、前記第１の基板のもう一方
の面に、前記第２の基板とほぼ同じ熱膨張率を有する材
料からなり、少なくとも一方の面が鏡面研磨された第３
の基板を同じく鏡面同士が向かい合うように密着した
後、加熱し、互いに強固に直接接合することを特徴とす
る複合基板材料の製造方法。1. A second substrate having a coefficient of thermal expansion different from that of the first substrate on one surface of a first substrate mirror-polished on both surfaces, and a second substrate mirror-polished on at least one surface. A third substrate, which is made of a material having substantially the same coefficient of thermal expansion as the second substrate on the other surface of the first substrate and at least one surface of which is mirror-polished,
A method for producing a composite substrate material, wherein the substrates are similarly adhered so that mirror surfaces thereof face each other, and then heated and directly bonded to each other.
らなる基板であることを特徴とする請求項１記載の複合
基板材料の製造方法。2. The method according to claim 1, wherein the third substrate is a substrate made of the same material as the second substrate.
特徴とする請求項１または２記載の複合基板材料の製造
方法。3. The method according to claim 1, wherein the third substrate is a glass substrate.
なくとも一方が、第１の基板材料に、珪素もしくは珪素
化合物を介して直接接合されることを特徴とする請求項
１または２記載の複合基板材料の製造方法。4. The method according to claim 1, wherein at least one of the second substrate and the third substrate is directly bonded to the first substrate material via silicon or a silicon compound. A method for manufacturing a composite substrate material.
とする請求項４記載の複合基板材料の製造方法。5. The method according to claim 4, wherein the silicon compound is silicon oxide.
とする請求項４記載の複合基板材料の製造方法。6. The method according to claim 4, wherein the silicon compound is silicon nitride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22765093A JP3194822B2 (en) | 1993-09-14 | 1993-09-14 | Manufacturing method of composite substrate material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22765093A JP3194822B2 (en) | 1993-09-14 | 1993-09-14 | Manufacturing method of composite substrate material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0786106A JPH0786106A (en) | 1995-03-31 |
| JP3194822B2 true JP3194822B2 (en) | 2001-08-06 |
Family
ID=16864198
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22765093A Expired - Fee Related JP3194822B2 (en) | 1993-09-14 | 1993-09-14 | Manufacturing method of composite substrate material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3194822B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6320206B1 (en) * | 1999-02-05 | 2001-11-20 | Lumileds Lighting, U.S., Llc | Light emitting devices having wafer bonded aluminum gallium indium nitride structures and mirror stacks |
| JP2001080974A (en) * | 1999-09-08 | 2001-03-27 | Fuji Photo Film Co Ltd | Composite base plate material and method for producing the same |
| FR2856192B1 (en) * | 2003-06-11 | 2005-07-29 | Soitec Silicon On Insulator | METHOD FOR PRODUCING HETEROGENEOUS STRUCTURE AND STRUCTURE OBTAINED BY SUCH A METHOD |
| JP5132534B2 (en) | 2008-12-01 | 2013-01-30 | 日本電波工業株式会社 | Manufacturing method of optical components |
| JP5234780B2 (en) * | 2008-12-24 | 2013-07-10 | 日本碍子株式会社 | Composite substrate manufacturing method and composite substrate |
| FR3068508B1 (en) * | 2017-06-30 | 2019-07-26 | Soitec | METHOD OF TRANSFERRING A THIN LAYER TO A SUPPORT SUBSTRATE HAVING DIFFERENT THERMAL EXPANSION COEFFICIENTS |
-
1993
- 1993-09-14 JP JP22765093A patent/JP3194822B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0786106A (en) | 1995-03-31 |
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