JP4633874B2 - Bonding SOI wafer bonding equipment - Google Patents

Description

【００３０】
また、前記不良率は、いずれも、接合ウェーハの総数に対する不良ウェーハの割合であり、超音波検出法によって接合後のウェーハ１，２の接合面を観察し、１つでもボイドが発生したものは不良として求めた。この結果が図３に示されている。なお、比較例Ｅの方法により接合したウェーハ１，２における不良率は図３に示していないが、比較例Ｅの方法により接合したウェーハ１，２における不良率は、比較例Ｂの方法により接合したウェーハ１，２における不良率と同等の値となった。
【００３１】
同図から明らかなように、本参考例の装置を用い、前記接合方法を用いてウェーハ１，２の接合を行なうと、前記不良率をほぼ零（５％以下）に近づけることができ、各比較例に比べて不良率を格段に小さくすることができることが確認された。
【００３２】
なお、図３に示す結果は、ウェーハ１，２の厚みや大きさを様々に変えて実験を行なった結果を示している。また、表１と図３を参照すると、ウェーハ１，２の中央部から接合を開始する場合に比べればウェーハ１，２の周辺部から接合を開始した方がボイドを抑制でき、押圧部材８を弾性力のあるものにより形成した場合に比べると押圧部材８を弾性力の無いものにより形成した方がボイドを抑制できることが分かる。
【００３３】
本参考例によれば、オリエンテーションフラット３，４形成領域の１ヶ所を、先端９が点接触押圧部と成した押圧部材８によって略点接触で押圧し、オリエンテーションフラット３，４形成領域の１ヶ所から発生させる押圧力の波をオリエンテーションフラット３，４形成領域の反対側に伝達させていってウェーハ１，２を接合することにより、上記結果から明らかなように、ウェーハ１，２にボイドが発生することを確実に抑制できる。
【００３４】
また、本参考例によれば、対のウェーハ１，２の被接合面１Ａ，２Ａ同士を対向させた状態で、先ずウェーハ１，２のオリエンテーションフラット３，４同士のみを位置合わせして接触させた後、ウェーハ１，２のオリエンテーションフラット３，４形成領域側から残りの領域を他端側に向けて順に接触させてウェーハ１，２の対向面同士を接合するために、図５の（ｃ）に示した方法のように、斜めの支持台３０にウェーハ１，２を重ねて支持する場合のようにウェーハ１，２の被接合面１Ａ，２Ａを傷つけることもない。
【００３５】
さらに、本参考例によれば、押圧部材挿入通路７に挿入する押圧部材８を押圧部材挿入通路７に沿って移動させるといった容易な動作によって、ウェーハ１，２のオリエンテーションフラット３，４形成領域の１ヶ所をウェーハ１，２の対向面を挟む両側から押圧してウェーハ１，２の接合を行なうものであるため、作業に熟練を要することなく、非常に容易にウェーハ１，２の接合を行なうことができる。
【００３６】
図４の（ａ）には、本発明に係る貼り合せＳＯＩウェーハの接合装置の実施形態例が、この装置によって接合される第１のウェーハ１の配置状態でブロック図により示されており、同図の（ｂ）〜（ｄ）には、この装置を用いて行われる貼り合せＳＯＩウェーハの接合工程図が示されている。
【００３７】
同図の（ａ）に示されるように、本実施形態例の接合装置は、ウェーハ配置部１７と、錐体部材配置手段１３と、錐体部材移動手段１４と、ウェーハ配置手段１５と、ウェーハ押圧手段１２を有しており、ウェーハ押圧手段１２にはウェーハ１，２のオリエンテーションフラット３，４形成領域の１ヶ所を押圧する押圧手段８が接続されている。
【００３８】
ウェーハ配置部１７は、接合されるウェーハ１，２を配置する領域であり、本実施形態例では、ウェーハ配置部１７のウェーハ配置面は平坦面と成している。また、ウェーハ配置部１７には、ウェーハ１，２のオリエンテーションフラット３，４を位置決めするための位置決め部（図示せず）が形成されている。
【００３９】
錐体部材配置手段１３は、ウェーハ配置部１７に被接合面１Ａを上側にして配置される第１のウェーハ１のウェーハ外周部上に、錐体部材１６の先端側を第１のウェーハ１の中央部側に向けて、少なくともオリエンテーションフラット３形成領域を含む３ヶ所に配置するものであり、本実施形態例では、錐体部材配置手段１３は、ウェーハ１のベベル部（ウェーハ外周部であり、半導体素子の実装などが行われない部分）のＡ，Ｂ，Ｃの３ヶ所位置に三角錐の錐体部材１６を配置するように構成されている。なお、錐体部材配置手段１３は、錐体部材１６を介してウェーハ１の上側にウェーハ２を配置したときに、ウェーハ１の被接合面１Ａとウェーハ２の被接合面２Ａとが略平行になるように、各錐体部材１６を配置する。
【００４０】
ウェーハ配置手段１５は、図４の（ｂ）に示すように、第２のウェーハ２を配置するものである。すなわち、ウェーハ配置手段１５は、第１のウェーハ１の上側に錐体部材１６を介し、被接合面２Ａを下側にし、かつ、第１のウェーハ１とオリエンテーションフラット３，４同士を位置合わせした状態で第２のウェーハ２を配置する。なお、ウェーハ配置手段１５は、第２のウェーハ２の被接合面２Ａと反対側の面を真空吸着した状態で、第１のウェーハ１の上側に搬送し、第１のウェーハ１の上側に配置した後に前記真空吸着を解除する。
【００４１】
錐体部材移動手段１４は、同図の（ｃ）に示すように、オリエンテーションフラット３，４形成領域に設けられた錐体部材１６（同図の（ａ）のＡの位置に設けられた錐体部材１６）をウェーハ１，２の外部に移動させることにより、第１のウェーハ１と第２のウェーハ２のオリエンテーションフラット３，４を接触させた後に、同図の（ｄ）に示すように、残りの錐体部材１６（同図の（ａ）のＢ，Ｃの位置に設けられた錐体部材１６）をウェーハ１，２の外部に移動させることにより第１のウェーハ１と第２のウェーハ２とを重ね合わせ接触させる。
【００４２】
ウェーハ押圧手段１２は、重ね合わされた第１と第２のウェーハ１，２のオリエンテーションフラット３，４形成領域の１ヶ所を押圧するものであり、同図の（ｄ）に示すように、第２のウェーハ２の上側から、押圧部材８によって、ウェーハ１，２のオリエンテーションフラット３，４形成領域の１ヶ所を押圧する。なお、本実施形態例でも、押圧部材８は、上記参考例に設けられる押圧部材８と同様の構成と成しており、押圧部材８の先端９は点接触押圧部と成している。
【００４３】
本実施形態例は以上のように構成されており、次に、本実施形態例の装置を用いた貼り合せＳＯＩウェーハの接合方法について説明する。まず、図４の（ａ）に示すように、適宜の手段によって、被接合面１Ａを上側にしてウェーハ１をウェーハ配置部１７に配置する。このとき、ウェーハ配置部１７に形成されている前記位置決め部（図示せず）に基づいてウェーハ１のオリエンテーションフラット３の位置決めをする。その後、錐体部材配置手段１３によって、ウェーハ１のベベル部のＡ，Ｂ，Ｃの位置に錐体部材１６を、その先端側がウェーハ１の中央部側に向くようにして配置する。
【００４４】
次に、同図の（ｂ）に示すように、ウェーハ配置手段１５によって、第１のウェーハ１の上側に、錐体部材１６を介し被接合面２Ａを下側にして第２のウェーハ２を配置する。このとき、ウェーハ配置部１７に形成されている前記位置決め部（図示せず）に基づいてウェーハ２のオリエンテーションフラット４の位置決めをすることにより、第１と第２のウェーハ１，２のオリエンテーションフラット３，４同士を位置合わせする。
【００４５】
次に、同図の（ｃ）に示すように、オリエンテーションフラット３，４形成領域に設けられた錐体部材１６をウェーハ１，２の外部に移動させることによりウェーハ１とウェーハ２のオリエンテーションフラット３，４を接触させた後に、同図の（ｄ）に示すように、残りの錐体部材１６をウェーハ１，２の外部に移動させることによりウェーハ１，２を重ね合わせ、ウェーハ押圧手段１２により、ウェーハ１，２のオリエンテーションフラット３，４形成領域の１ヶ所を押圧部材８の先端９によって略点接触で押圧する。
【００４６】
本実施形態例によれば、上記参考例と同様に、オリエンテーションフラット３，４形成領域の１ヶ所を、先端９が点接触押圧部と成した押圧部材８によって略点接触で押圧し、オリエンテーションフラット３，４形成領域の１ヶ所から発生させる押圧力の波をオリエンテーションフラット３，４形成領域の反対側に伝達させていってウェーハ１，２を接合することにより、上記参考例と同様に、容易な操作によって、ウェーハ１，２にボイドが発生することを確実に抑制できる。
【００４７】
また、本実施形態例では、上記参考例と異なり、ウェーハ１，２を重ね合わせてから接合するが、ウェーハ１，２をウェーハ配置部１７に水平に配置するために、図５の（ｃ）に示したように、斜めの支持台３０にウェーハ１，２を重ね合わせて支持する場合と異なり、ウェーハ１，２の被接合面１Ａ，２Ａを傷つけることもなく、上記参考例と同様の効果を奏することができる。
【００４８】
なお、本発明は上記実施形態例に限定されることはなく、様々な実施の態様を採り得る。また、上記参考例に関しても上記以外の様々な実施の態様を採り得る。例えば、上記参考例では、押圧部材８を手動によってウェーハ挿入凹部５側に移動するようにしたが、貼り合せＳＯＩウェーハの接合装置は、図１の（ｃ）の鎖線に示すように、押圧部材挿入通路７に沿って押圧部材８をウェーハ挿入凹部５側へ移動させることによって対のウェーハ１，２の対向面を挟む両側からウェーハ１，２を押圧するウェーハ押圧手段１２を設け、このウェーハ押圧手段によって、自動的に押圧部材８を移動させてウェーハ１，２の接合を行なうようにしてもよい。なお、ウェーハ押圧手段１２は、例えばエアシリンダーなどを設けて構成される。
【００４９】
また、上記実施形態例では、ウェーハ配置部１７は平坦面を有していたが、図４の（ｄ）に示すように、ウェーハ配置部１７に先端が点接触押圧部と成した突起部１８を設けてもよい。この突起部１８を、押圧部材８によって押圧する位置の反対側に設けておけば、上記実施形態例の装置を用いて、ウェーハ１，２のオリエンテーションフラット３，４形成領域の１ヶ所をウェーハ１，２の対向面を挟む両側から略点接触で押圧してウェーハ１，２を接合することができる。
【００５０】
さらに、上記実施形態例では、錐体部材１６を三角錐の部材としたが、錐体部材１６は必ずしも三角錐の部材とするとは限らず、他の多角錐部材としてもよいし、円錐の部材としてもよい。
【００５１】
さらに、上記実施形態例では、錐体部材１６をウェーハ１の外周部の３ヶ所に設けたが、錐体部材１６をウェーハ１の外周部の４ヶ所以上に設けてもよい。この場合も、錐体部材１６をオリエンテーションフラット形成領域とそれ以外の領域とに設け、錐体部材１６を介してウェーハ１の上側にウェーハ２を設けたときに、ウェーハ１の被接合面１Ａとウェーハ２の被接合面２Ａとが略平行になるように配置する。
【００５２】
さらに、上記実施形態例では、図２の（ｂ）に示したように、対のウェーハ１，２のオリエンテーションフラット３，４形成領域の中央部を押圧するようにしたが、オリエンテーションフラット３，４の形成領域の１ヶ所であれば、同図の（ｃ）のＡで示す領域（オリエンテーションフラット３，４から１０ｍｍ程度内側までの領域）のいずれの部位を押圧するようにしてもよい。
【００５３】
なお、本発明はオリエンテーションフラットを形成しているウェーハに関して開示しているものではあるが、オリエンテーションフラットに代わるたとえばノッチ等が形成されたウェーハに関しても、ノッチ形成領域の１ケ所を点接触押圧で開始することにより同様の効果は期待できる。すなわち、ウェーハ中心に対して非対称形状を形成している部位は、貼合わせの際の押圧力の波が伝播に伴い干渉作用を起こしやすく、そこでのボイドの発生が充分予測されるからである。
【００５４】
【発明の効果】
本発明の貼り合せＳＯＩウェーハの接合装置によれば、オリエンテーションフラット形成領域の１ヶ所を先端が点接触押圧部と成した押圧部材によって略点接触で押圧し、オリエンテーションフラット形成領域の１ヶ所から発生させる押圧力の波をオリエンテーションフラット形成領域の反対側に伝達させていってウェーハを接合するため、非常に容易に、ボイドの発生を抑制することができるし、接合によってウェーハの被接合面を傷つけることもない。
【００５５】
さらに、対のウェーハの被接合面同士を対向させた状態で先ずウェーハのオリエンテーションフラット同士のみを位置合わせして接触させた後、この位置合わせされたオリエンテーションフラット形成領域の１ヶ所を押圧する押圧部材の押圧力によって前記対のウェーハのオリエンテーションフラット形成領域側から残りの領域を他端側に向けて順に接触させてウェーハの対向面同士を接合する構成であるので、より一層ボイド発生抑制効果を発揮することができる。
【００５６】
また、本発明の貼り合せＳＯＩウェーハの接合装置によれば、非常に簡単な装置構成で、上記効果を奏することができる優れた装置とすることができる。
【図面の簡単な説明】
【図１】 貼り合せＳＯＩウェーハの接合装置の参考例を断面図により示す要部構成図である。
【図２】 参考例および本実施形態例に適用される押圧部材先端形状例（ａ）とウェーハの押圧部位（ｂ）、（ｃ）をそれぞれ示す説明図である。
【図３】 参考例に係る貼り合せＳＯＩウェーハの接合方法によりウェーハを接合したときの不良率を従来の貼り合せＳＯＩウェーハの接合方法（比較例）によりウェーハを接合したときの不良率と比較して示すグラフである。
【図４】 本発明に係る貼り合せＳＯＩウェーハの接合装置の実施形態例の要部構成と、この装置を用いた貼り合せＳＯＩウェーハの接合工程図である。
【図５】 従来の貼り合せＳＯＩウェーハの接合方法を示す説明図である。
【図６】 従来の貼り合せＳＯＩウェーハの接合方法を用いた場合のウェーハの接合態様と、接合態様によってボイドが発生し易い部位を模式的に示した説明図である。
【符号の説明】
１，２ ウェーハ
１Ａ，２Ａ 被接合面
３，４ オリエンテーションフラット
５ ウェーハ挿入凹部
６ 側壁
７ 押圧部材挿入通路
８ 押圧部材
９ 先端
１１ 保持台
１２ ウェーハ押圧手段
１３ 錐体部材配置手段
１４ 錐体部材移動手段
１５ ウェーハ配置手段
１６ 錐体部材[0001]
BACKGROUND OF THE INVENTION
In the present invention, for example, a bonded SOI wafer that bonds and bonds a pair of wafers such as a base wafer and an active wafer is bonded. Combination Is related to the device
[0002]
[Prior art]
Conventionally, bonding of a bonded SOI (Silicon On Insulation) wafer in which semiconductor wafers formed of silicon are bonded together or bonded via an insulator is performed, and the bonded bonded SOI wafer is It is applied to semiconductor substrates.
[0003]
A bonded SOI wafer is generally formed by bonding a base wafer and an active wafer. If voids (unbonded portions) due to bubbles remain at the bonded portion of the bonded SOI wafer, the bonded SOI wafer is Since it cannot be applied to uses such as a semiconductor substrate, it is desired to bond bonded SOI wafers without generating voids.
[0004]
Thus, various methods have been proposed as bonding SOI wafer bonding methods that suppress the generation of voids, for example, as shown in FIGS. The one shown in (a) of the figure is described in Japanese Patent Application Laid-Open No. 8-51050, where the bonded surfaces 1A and 2A of the two wafers 1 and 2 to be bonded are opposed to each other, and at least one of them is shown. The wafer (wafer 1 in the figure) is bent into a convex shape by, for example, vacuum suction, and the central portions of the wafers 1 and 2 are brought into contact with each other. In this method, the wafers 1 and 2 are sequentially brought into contact with each other and bonded together.
[0005]
The one shown in (b) of the figure is described in Japanese Patent Publication No. 2846994, and the bonded surfaces of the two wafers 1 and 2 to be bonded are opposed to each other, and at least one wafer (in the figure, Wafer 1) is curved and deformed into a convex shape, a part of the peripheral part of wafers 1 and 2 is brought into contact, and wafers 1 and 2 are brought into contact in this order from the joining start part toward the other end. It is the method of joining the opposing surfaces of each other.
[0006]
The one shown in (c) of the figure is described in Japanese Patent Application Laid-Open No. 9-97755, and the surface to be joined 1A is placed on the support base 30 fixed at an angle of 70 to 90 °. Then, the wafer 1 is placed on the wafer 2 so that the bonded surfaces 2A face each other, and then the peripheral portion of the wafer 2 is pressed by the convex pressing portion 31 made of an elastic body. It is the method of joining the opposing surfaces of each other.
[0007]
(D) in FIG. 6 is described in Japanese Patent Application Laid-Open No. 8-69952, in which the wafer 1 is fixed to the support table 30 and the orientation flat (OF) 4 vicinity of the wafer 2 is formed. Is adsorbed by the adsorbing portion 32 at the tip of the vacuum tweezers 33 and placed on the upper side of the wafer 1, and only the orientation flats 3 and 4 are brought into contact with each other and lightly pressed by the adsorbing portion 32 while releasing the adsorption of the vacuum tweezers 33. This is a method in which the opposite surfaces of the wafers 1 and 2 are bonded to each other by superimposing the wafers 1 and 2 by their own weight.
[0008]
[Problems to be solved by the invention]
However, when the present inventors actually joined the wafers 1 and 2 using the bonded SOI wafer joining method as shown in FIGS. 5A to 5D, FIG. In the method of bonding from the center part of the wafers 1 and 2 to the peripheral part as in the method shown in FIG.
[0009]
Further, in the method of bonding from one end side to the other end side of the wafers 1 and 2 as in the method shown in FIGS. 5B to 5D, the method shown in FIG. Although it is easy to suppress the generation of voids, as shown in FIG. 6A, when bonding is performed from the opposite side to the orientation flat 3 or 4 side to the orientation flat 3 or 4 side, It turned out that the void 5 tends to generate | occur | produce in the places (especially orientation flats 3 and 4 part) as shown in (b).
[0010]
Furthermore, even when joining is performed from the formation region side of the orientation flats 3 and 4 toward the opposite side of the orientation flats 3 and 4, as in the method shown in FIG. It can be seen that when the wafers 1 and 2 are pressed, voids are likely to occur. Further, as shown in FIG. As shown in (d), the void 5a is likely to be generated in the pressing portion, and when the suction portion 32 of the vacuum tweezers 33 moves away from the formation portion of the orientation flats 3 and 4, the voids 5b are formed in the orientation flats 3 and 4 portions. It was found that is likely to occur.
[0011]
As described above, in the conventional bonded SOI wafer bonding method, it is not possible to suppress the occurrence of voids particularly in the orientation flats 3 and 4 using any of them, and (a) in FIG. In the method shown in (b), there is a problem that the wafers 1 and 2 to be bent are easily distorted. In the method shown in (c) of FIG. In such a case, there is a problem that the opposing surfaces of the wafers 1 and 2 are likely to be damaged due to a slight displacement of the wafers 1 and 2. In the method shown in FIG. There was a problem that adjustment and pressing timing had to be performed manually by skilled workers.
[0012]
The present invention has been made to solve the above-described conventional problems, and the purpose thereof is to prevent the occurrence of scratches on the bonded surfaces of the wafers to be bonded, and to easily bond the voids without fail. Of bonded SOI wafer that can suppress Combination Is to provide a place.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration as means for solving the problems. That is, Book The invention A wafer placement portion, and a plurality of locations on the wafer outer peripheral portion of the first wafer placed on the wafer placement portion with the surface to be bonded facing upward, with the tip side of the cone member facing the center portion side of the first wafer Cone member arrangement means arranged at three locations including at least an orientation flat forming region, a surface to be joined with the cone member on the upper side of the first wafer, and the first wafer and the orientation flat The wafer placement means for placing the second wafer in a state in which they are aligned with each other, the cone member, and first the cone member arranged in the orientation flat forming region is first moved to the outside to move the first and second After the first wafer and the orientation flat are brought into contact with each other, the remaining cone members are moved to the outside of the wafer to move the first wafer and the first flat. Of the first and second wafers in which all the pyramid members are moved to the outside and the surfaces to be joined are overlapped with each other. There is a wafer pressing means that presses from one side of the orientation flat forming area from the orientation flat to the inner side of the 10 mm from the outside of the wafer by a substantially point contact with a pressing member whose pressing tip forms a point contact pressing part. This is a means to solve the problem.
[0014]
As described above, the inventor of the present invention pays attention to the fact that voids are likely to be generated in the orientation flat portion of the wafer when the conventional bonding SOI wafer bonding method is used. It was thought that the occurrence of voids in the orientation flat part could be suppressed by using these locations.
[0015]
That is, when at least one part of the wafer is brought into contact with the bonded surfaces of the pair of wafers facing each other and the wafer is pressed by the pressing member, the pressing force by the pressing member is transmitted and bonding proceeds. Compared to the case where the wave of pressure transmission hits the edge of the arc-shaped wafer, when it hits the linear orientation flat part almost perpendicularly, it is difficult for air to escape, so it seems that voids are likely to occur. The inventors thought that it would be easier to suppress the generation of voids in the orientation flat portion by pressing one location in the orientation flat formation region and transmitting the pressing force from the orientation flat formation region.
[0016]
In addition, as in the conventional method, when the pressing member is formed of an elastic body, or when the tip of the pressing member is formed in a wide area, the pressing member presses the wafer in surface contact, For example, as shown in FIG. 6C, the wave of the pressure transmission is transmitted from a plurality of locations, and the wave of the wave of the transmission of the pressure is collided. By considering that interference may occur and voids are generated, it is possible to suppress voids by pressing one point of the orientation flat forming region with approximately point contact by a pressing member whose tip is a point contact pressing part. I thought.
[0017]
Based on such an idea, the present inventor made approximately one point contact of the orientation flat forming region of the wafer aligned with the bonded surfaces facing each other by a pressing member whose tip is a point contact pressing portion. Considering a method of bonding bonded SOI wafers by pressing, and examining the defect rate when wafers were bonded by this method, the defect rate was able to approach nearly zero (5% or less).
[0018]
The defect rate is the ratio of defective wafers to the total number of bonded wafers, and any one of the bonded wafers with voids was determined as defective. This defect rate is affected by particles being bonded (such as dust adhering to the bonded surface of the wafer). If the present invention is applied under the condition that the particles are completely removed, the defect rate is reduced to zero. The inventor believes that this can be achieved.
[0019]
Bonding SOI wafers of the present invention apparatus Based on the above-mentioned experimental study by the inventors, one of the orientation flat forming regions is pressed at a substantially point contact by a pressing member whose tip is a point contact pressing portion, and a pressing generated from one of the orientation flat forming regions is performed. Since this is a method of joining the wafer by transmitting the pressure wave to the opposite side of the orientation flat forming region, it is possible to suppress the generation of voids.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, For convenience of explanation, a reference example is first described before the description of the embodiment. Reference examples and In the description of the present embodiment, the same reference numerals are assigned to the same name portions as those in the conventional example, and the duplicate description is omitted. FIG. 1 shows an example of a bonding SOI wafer bonding apparatus according to the present invention. reference The main configuration and operation of the example are shown by a bonding process diagram of a bonded SOI wafer performed using this apparatus.
[0021]
Book reference As shown in the figure, the apparatus of the example has a holding table 11 having a wafer insertion recess 5 having a substantially V-shaped cross section, and both side walls 6 of the wafer insertion recess 5 are formed as wafer insertion recesses. The wafer 1 and the wafer 2 inserted into the wafer 5 are formed as a wafer leaning slope that leans with the orientation flats 3 and 4 on the lower side so that the wafer surface is inclined. Book reference In the example, the angle X shown in the figure of the side wall 6 is formed at about 80 °. The bottom surface 10 of the wafer insertion recess 5 is provided with a positioning portion (not shown) for aligning the orientation flats 3 and 4 of the wafers 1 and 2.
[0022]
The holding table 11 is formed with a pair of pressing member insertion passages 7. reference In the example, the pressing member insertion passage 7 is formed by a hole penetrating from the wafer insertion recess 5 to the outside of the holding table 11. The pressing member insertion passage 7 is pressed into one of the orientation flat 3 and 4 forming regions from both sides of the opposing surfaces of the pair of wafers 1 and 2 that are inserted into the wafer insertion recess 5 and oppose the bonded surfaces 1A and 2A. This is an insertion passage for the pair of pressing members 8.
[0023]
The pressing member 8 has a hemispherical shape as shown in FIG. 2A on the front end 9 side, and the front end 9 forms a point contact pressing portion, whereby the orientation flats 3 and 4 of the wafers 1 and 2 are formed. One place of the forming region can be pressed by substantially point contact. In addition, although the magnitude | size and shape of the press member 8 are not specifically limited, It is desirable that the diameter of the hemispherical shape by the side of the front-end | tip 9 shall be 15 mm or less. The hardness of the tip 9 of the pressing member 8 is preferably smaller than that of silicon and larger than that of a registered trademark product member known as Teflon. By setting it to an appropriate value, the orientation flats 3 and 4 forming area of the wafers 1 and 2 can be pressed without damaging the wafers 1 and 2 and by optimizing the pressing force.
[0024]
Book reference In the apparatus of the example, the pressing member 8 inserted into the pressing member insertion passage 7 causes one position (for example, the pressing portion shown in FIG. 2B) of the orientation flats 3 and 4 to face the wafers 1 and 2. By pressing from both sides of the surface, the opposing surfaces of the pair of wafers 1 and 2 are joined together. reference A bonded SOI wafer bonding method using the example apparatus will be described.
[0025]
First, as shown in FIG. 1 (a), the wafers 1 and 2 are inserted into the wafer insertion recess 5 of the holding table 11, the orientation flats 3 and 4 of the wafers 1 and 2 are placed on the lower side, 2A are opposed to each other, and the wafer surface is inclined so as to be inclined. At this time, the orientation flats 3 and 4 of the wafers 1 and 2 are aligned based on the positioning part (not shown) formed in the wafer insertion recess 5.
[0026]
Next, in this state, as shown in FIG. 5B, the pressing members 8 are respectively inserted into the pair of pressing member insertion passages 7, and the distal end 9 side of each pressing member 8 is extended along the pressing member insertion passage 7. Then, the wafer is moved to the wafer insertion recess 5 side, the lower side of the wafers 1 and 2 is pushed by the pressing member 8, and only the orientation flats 3 and 4 are brought into contact with each other.
[0027]
Then, by further moving the tip 9 side of each pressing member 8 to the wafer insertion recess 5 side along the pressing member insertion passage 7, as shown in FIG. 4 is pressed at one point in the formation region from both sides of the opposing surfaces of the wafers 1 and 2 by a pressing member 8 in a substantially point contact, and the orientation flats 3 and 4 of the pair of wafers 1 and 2 are pressed by the pressing force of the pressing member 8. The remaining areas are sequentially contacted from the formation area side toward the other end side to bond the opposing surfaces of the wafers 1 and 2 together.
[0028]
The present inventor found that the bonded wafer was bonded and bonded by the bonded SOI wafer bonding method shown in Table 1 with respect to the void generation state and the defect rate when the bonded SOI wafer was bonded by the above method. It was examined in comparison with the occurrence of voids and the defect rate. In addition, the bonding method of the bonded SOI wafer of each comparative example shown in Table 1 is a method determined based on the conventional bonding method of bonded SOI wafer, and Table 1 shows each bonded SOI wafer bonding method. And the occurrence of voids.
[0029]
[Table 1]

[0030]
In addition, the defect rate is the ratio of the defective wafer to the total number of bonded wafers, and the bonded surfaces of the wafers 1 and 2 after bonding are observed by an ultrasonic detection method. Sought as bad. The result is shown in FIG. The defect rate in wafers 1 and 2 bonded by the method of Comparative Example E is not shown in FIG. 3, but the defect rate in wafers 1 and 2 bonded by the method of Comparative Example E is bonded by the method of Comparative Example B. It became a value equivalent to the defective rate in the wafers 1 and 2.
[0031]
As is clear from the figure, the book reference When the wafers 1 and 2 are bonded using the above-described bonding method using the apparatus of the example, the defective rate can be brought close to zero (5% or less), and the defective rate is markedly higher than each comparative example. It was confirmed that it can be made smaller.
[0032]
The results shown in FIG. 3 show the results of experiments performed by changing the thicknesses and sizes of the wafers 1 and 2 in various ways. Further, referring to Table 1 and FIG. 3, compared to the case where the bonding is started from the central portion of the wafers 1, 2, the void can be suppressed when the bonding is started from the peripheral portion of the wafers 1, 2. It can be seen that voids can be suppressed when the pressing member 8 is formed of a member having no elastic force as compared with a case of forming the member with an elastic force.
[0033]
Book reference According to the example, one portion of the orientation flats 3 and 4 forming region is pressed by a point member by the pressing member 8 having the tip 9 formed as a point contact pressing portion, and is generated from one point of the orientation flats 3 and 4 forming region. As shown in the above results, voids are generated in the wafers 1 and 2 when the wave of the pressing force is transmitted to the opposite side of the orientation flats 3 and 4 and the wafers 1 and 2 are joined. Can be reliably suppressed.
[0034]
Also book reference According to the example, with the bonded surfaces 1A and 2A of the pair of wafers 1 and 2 facing each other, the orientation flats 3 and 4 of the wafers 1 and 2 are first aligned and brought into contact with each other, and then the wafers are contacted. In order to join the remaining areas in order from the formation flat side of the 1 and 2 orientation flats 3 and 4 toward the other end side, the opposing surfaces of the wafers 1 and 2 are bonded to each other as shown in FIG. Unlike the method, the bonded surfaces 1A and 2A of the wafers 1 and 2 are not damaged as in the case where the wafers 1 and 2 are supported on the inclined support table 30 in an overlapping manner.
[0035]
In addition, book reference According to the example, one portion of the orientation flats 3 and 4 forming region of the wafers 1 and 2 is moved to the wafer by an easy operation of moving the pressing member 8 inserted into the pressing member insertion passage 7 along the pressing member insertion passage 7. Since the wafers 1 and 2 are joined by pressing from both sides of the opposing surfaces 1 and 2, the wafers 1 and 2 can be joined very easily without requiring skill in the work.
[0036]
FIG. 4A shows a bonded SOI wafer bonding apparatus according to the present invention. The fruit An example of the embodiment is shown by a block diagram in the arrangement state of the first wafer 1 bonded by this apparatus, and (b) to (d) in FIG. A bonding process diagram of an SOI wafer is shown.
[0037]
As shown in (a) of the figure, Real The bonding apparatus according to the embodiment includes a wafer placement unit 17, a cone member placement unit 13, a cone member moving unit 14, a wafer placement unit 15, and a wafer pressing unit 12. Is connected to a pressing means 8 for pressing one of the orientation flats 3 and 4 forming regions of the wafers 1 and 2.
[0038]
The wafer placement unit 17 is a region in which the wafers 1 and 2 to be bonded are placed, and in this embodiment, the wafer placement surface of the wafer placement unit 17 is a flat surface. The wafer placement portion 17 is formed with a positioning portion (not shown) for positioning the orientation flats 3 and 4 of the wafers 1 and 2.
[0039]
The cone member placement means 13 is arranged on the wafer outer peripheral portion of the first wafer 1 placed on the wafer placement portion 17 with the bonded surface 1A facing upward, and the tip end side of the cone member 16 is placed on the first wafer 1. It is arranged at three locations including at least the orientation flat 3 formation region toward the center side, and in this embodiment, the cone member arrangement means 13 is a bevel portion of the wafer 1 (wafer outer peripheral portion, The triangular pyramid member 16 is arranged at three positions A, B, and C of the portion where the semiconductor element is not mounted). Note that when the wafer 2 is placed on the upper side of the wafer 1 via the cone member 16, the cone member arranging means 13 has the bonded surface 1 </ b> A of the wafer 1 and the bonded surface 2 </ b> A of the wafer 2 substantially parallel to each other. Each cone member 16 is arranged so as to be.
[0040]
The wafer placement means 15 places the second wafer 2 as shown in FIG. That is, the wafer placement means 15 has the bonded surface 2A on the lower side via the cone member 16 on the upper side of the first wafer 1, and the first wafer 1 and the orientation flats 3 and 4 are aligned with each other. The second wafer 2 is placed in the state. The wafer placement means 15 conveys the surface of the second wafer 2 opposite to the bonded surface 2 </ b> A to the upper side of the first wafer 1 while being vacuum-sucked, and places the second wafer 2 on the upper side of the first wafer 1. After that, the vacuum suction is released.
[0041]
As shown in (c) of the figure, the cone member moving means 14 is provided with a cone member 16 provided in the orientation flat 3 and 4 formation region (the cone provided at the position A in (a) of the figure). After the body member 16) is moved to the outside of the wafers 1 and 2, the orientation flats 3 and 4 of the first wafer 1 and the second wafer 2 are brought into contact with each other, as shown in FIG. By moving the remaining cone members 16 (the cone members 16 provided at positions B and C in FIG. 5A) to the outside of the wafers 1 and 2, the first and second wafers 1 and 2 are moved. The wafer 2 is overlapped and brought into contact.
[0042]
The wafer pressing means 12 presses one of the orientation flats 3 and 4 forming regions of the superimposed first and second wafers 1 and 2, and as shown in FIG. From the upper side of the wafer 2, one portion of the orientation flat 3, 4 forming region of the wafer 1, 2 is pressed by the pressing member 8. In the present embodiment, the pressing member 8 is reference The configuration is the same as that of the pressing member 8 provided in the example, and the tip 9 of the pressing member 8 is a point contact pressing portion.
[0043]
Real The embodiment is configured as described above. Next, a bonding SOI wafer bonding method using the apparatus of this embodiment will be described. First, as shown in FIG. 4A, the wafer 1 is placed on the wafer placement portion 17 with the surface to be joined 1 </ b> A facing upward by appropriate means. At this time, the orientation flat 3 of the wafer 1 is positioned based on the positioning portion (not shown) formed in the wafer placement portion 17. Thereafter, the cone member 16 is arranged at the positions A, B, and C of the bevel portion of the wafer 1 by the cone member arrangement means 13 so that the front end side thereof faces the center portion side of the wafer 1.
[0044]
Next, as shown in (b) of the figure, the second wafer 2 is placed on the upper side of the first wafer 1 with the surface to be joined 2A on the lower side via the cone member 16 by the wafer placement means 15. Deploy. At this time, the orientation flat 4 of the first and second wafers 1 and 2 is positioned by positioning the orientation flat 4 of the wafer 2 based on the positioning portion (not shown) formed in the wafer placement portion 17. , 4 are aligned.
[0045]
Next, as shown in FIG. 2C, the orientation flats 3 of the wafers 1 and 2 are moved by moving the cone members 16 provided in the orientation flats 3 and 4 formation area to the outside of the wafers 1 and 2. , 4 are brought into contact with each other, and the remaining cone members 16 are moved outside the wafers 1, 2 as shown in FIG. Then, one of the orientation flats 3 and 4 forming regions of the wafers 1 and 2 is pressed by the tip 9 of the pressing member 8 in a substantially point contact.
[0046]
According to this embodiment, the above reference As in the example, one point in the orientation flats 3 and 4 formation region is pressed by a point member 8 having a tip 9 formed as a point contact pressing part, and is generated from one point in the orientation flats 3 and 4 formation region. By transmitting the wave of the pressing force to be transmitted to the opposite side of the orientation flats 3 and 4 formation region, reference Similarly to the example, it is possible to reliably suppress the generation of voids in the wafers 1 and 2 by an easy operation.
[0047]
Also, Real In the embodiment example, the above reference Unlike the example, the wafers 1 and 2 are joined after being overlapped. In order to place the wafers 1 and 2 horizontally on the wafer placement portion 17, as shown in FIG. Unlike the case where the wafers 1 and 2 are overlapped and supported on the wafer 30, the bonded surfaces 1A and 2A of the wafers 1 and 2 are not damaged, reference The same effect as the example can be achieved.
[0048]
In addition, this invention is not limited to the said embodiment example, Various aspects can be taken. In addition, various embodiments other than the above can be adopted with respect to the reference example. For example, the above reference In the example, the pressing member 8 is manually moved to the wafer insertion concave portion 5 side. However, the bonding SOI wafer bonding apparatus is arranged in the pressing member insertion passage 7 as shown by a chain line in FIG. A wafer pressing means 12 for pressing the wafers 1 and 2 from both sides sandwiching the opposing surfaces of the pair of wafers 1 and 2 by moving the pressing member 8 toward the wafer insertion recess 5 side is provided. Alternatively, the pressing member 8 may be moved to bond the wafers 1 and 2 together. The wafer pressing means 12 is configured by providing an air cylinder, for example.
[0049]
Also on Real In the embodiment, the wafer placement portion 17 has a flat surface. However, as shown in FIG. 4D, the wafer placement portion 17 is provided with a protrusion 18 whose tip is a point contact pressing portion. Also good. If this protrusion 18 is provided on the opposite side of the position pressed by the pressing member 8, one of the orientation flats 3, 4 formation region of the wafers 1, 2 is formed on the wafer 1 using the apparatus of the above embodiment. The wafers 1 and 2 can be bonded by pressing at substantially point contact from both sides of the two opposing surfaces.
[0050]
Furthermore, in the above embodiment, the pyramid member 16 is a triangular pyramid member. However, the pyramid member 16 is not necessarily a triangular pyramid member, and may be another polygonal pyramid member or a conical member. It is good.
[0051]
Furthermore, on Real In the embodiment, the cone member 16 is provided at three locations on the outer peripheral portion of the wafer 1, but the cone member 16 may be provided at four or more locations on the outer peripheral portion of the wafer 1. Also in this case, when the cone member 16 is provided in the orientation flat forming region and the other region, and the wafer 2 is provided on the upper side of the wafer 1 via the cone member 16, the bonded surface 1A of the wafer 1 and It arrange | positions so that to-be-joined surface 2A of the wafer 2 may become substantially parallel.
[0052]
Furthermore, on Real In the embodiment, as shown in FIG. 2B, the central portion of the orientation flats 3 and 4 forming regions of the pair of wafers 1 and 2 is pressed. If it is one place, you may make it press any part of the area | region (area | region from the orientation flats 3 and 4 to about 10 mm inside) shown by A of (c) of the figure.
[0053]
In addition, although this invention is disclosed regarding the wafer which forms orientation flat, also about the wafer in which notch etc. were formed instead of orientation flat, one place of a notch formation area is started by point contact press. By doing so, the same effect can be expected. That is, the portion where the asymmetric shape is formed with respect to the center of the wafer is likely to cause an interference action with the propagation of the wave of the pressing force at the time of bonding, and the occurrence of voids therein is sufficiently predicted.
[0054]
【The invention's effect】
Bonding SOI wafers of the present invention apparatus According to the present invention, one point of the orientation flat forming region is pressed by a pressing member whose tip is a point contact pressing part in a substantially point contact, and a wave of pressing force generated from one point of the orientation flat forming region is generated. Therefore, the generation of voids can be suppressed very easily, and the bonded surface of the wafer is not damaged by the bonding.
[0055]
Further, in a state in which the bonded surfaces of the pair of wafers face each other, first, only the orientation flats of the wafers are aligned and brought into contact with each other, and then a pressing member that presses one position of the aligned orientation flat forming region A structure in which the facing surfaces of the pair of wafers are brought into contact with each other in order from the orientation flat forming region side of the pair of wafers toward the other end side by the pressing force of the pair of wafers. So A void generation suppressing effect can be further exhibited.
[0056]
Also, Of the present invention According to the bonded SOI wafer bonding device, the top configuration is very simple. Effect It can be set as the outstanding apparatus which can show a fruit.
[Brief description of the drawings]
[Figure 1] Pasted Of bonded SOI wafer bonding equipment reference It is a principal part block diagram which shows an example with sectional drawing.
[Figure 2] Reference example and this embodiment It is explanatory drawing which shows the press member front-end | tip shape example (a) applied to 1 and the press part (b) of a wafer, and (c), respectively.
[Fig. 3] Reference example 6 is a graph showing a defect rate when a wafer is bonded by a bonding method for bonded SOI wafers according to the present invention and a defect rate when a wafer is bonded by a bonding method (comparative example) of a conventional bonded SOI wafer.
FIG. 4 shows a bonding SOI wafer bonding apparatus according to the present invention. The fruit It is a principal part structure of the example of an embodiment, and a bonding process figure of a bonded SOI wafer using this device.
FIG. 5 is an explanatory view showing a conventional bonding method for a bonded SOI wafer.
FIG. 6 is an explanatory view schematically showing a wafer bonding mode and a portion where voids are likely to be generated depending on the bonding mode when a conventional bonded SOI wafer bonding method is used.
[Explanation of symbols]
1, 2 wafers
1A, 2A surface to be joined
3,4 Orientation flat
5 Wafer insertion recess
6 Side walls
7 Press member insertion passage
8 Pressing member
9 Tip
11 Holding stand
12 Wafer pressing means
13 Cone member arrangement means
14 Cone member moving means
15 Wafer placement means
16 Cone member

Claims (1)

A wafer placement portion, and a plurality of locations on the wafer outer peripheral portion of the first wafer placed on the wafer placement portion with the surface to be bonded facing upward, with the tip side of the cone member facing the center portion side of the first wafer Cone member arrangement means arranged at three locations including at least an orientation flat forming region, a surface to be joined with the cone member on the upper side of the first wafer, and the first wafer and the orientation flat The wafer placement means for placing the second wafer in a state in which they are aligned with each other, the cone member, and first the cone member placed in the orientation flat forming region is first moved to the outside to move the first and second the wafer and the orientation flat together after contacted first, the first wafer by moving the remaining cone member to the wafer outside the A cone member moving means for superimposing by overall contacting the surface to be bonded with the wafer, all the cone member of the first and second wafer is moved to the outside to be bonded faces superimposed There is provided a wafer pressing means for pressing from one side of the orientation flat forming region from the orientation flat to the inner side of the 10 mm from the outside of the wafer by a substantially point contact by a pressing member having a pressing tip formed as a point contact pressing portion. Bonding SOI wafer bonding equipment.

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