JP2006111938A

JP2006111938A - Electroless plating apparatus

Info

Publication number: JP2006111938A
Application number: JP2004301908A
Authority: JP
Inventors: Miho Jomen; 美保定免; Kenichi Hara; 謙一原
Original assignee: Tokyo Electron Ltd
Current assignee: Tokyo Electron Ltd
Priority date: 2004-10-15
Filing date: 2004-10-15
Publication date: 2006-04-27
Also published as: CN1769520A; KR100751102B1; KR20060052152A; US20060081461A1

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize a condition of an electroless plating solution and to stably plate the surface of a substrate with the plating solution, by avoiding a problem that an electroless plating solution used in an electroless plating step carried out in a process of manufacturing a semiconductor device deposits a metal in the solution and becomes an unstable state, particularly when used in a heated condition, because of containing a reducing agent which is a supply source of electrons. <P>SOLUTION: This electroless plating apparatus comprises: chemical-solution-feeding channels for independently passing a first chemical solution containing a metal salt and a second chemical solution including a reducing agent, both of which constitute the electroless plating solution; opening/closing means installed in the vicinity of the confluence and in each of the chemical-solution-feeding channel; and an opening/closing means for the plating solution installed in the vicinity of a discharge opening in the channel for feeding the electroless plating solution after the two channels are joined. By this configuration, the electroless plating apparatus stores the plating solution in an approximately necessary amount to be spouted during one plating step, in the feeding channel sandwiched between both of the opening/closing means, and keeps both of the chemical solutions mixed only in a period after plating treatment for one substrate has been started and before the treatment for the next substrate begins. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、基板上に無電解めっき液を供給して基板表面、例えば半導体基板の配線金属の表面をめっきするための無電解めっき装置に関するものである。 The present invention relates to an electroless plating apparatus for supplying an electroless plating solution onto a substrate and plating a substrate surface, for example, a surface of a wiring metal of a semiconductor substrate.

半導体デバイスの多層化構造は、層間絶縁膜に配線を埋め込んだ層を多段に積層して構成される。エレクトロマイグレーションに強い好ましい配線材料としては例えば銅が用いられており、その配線を形成する手法としては、層間絶縁膜に溝を含む凹部を形成し、この凹部に銅を埋め込んだ後、余剰の銅をＣＭＰと呼ばれる研磨法により研磨するダマシンプロセスが採用されている。 A multilayered structure of a semiconductor device is configured by stacking layers in which wiring is embedded in an interlayer insulating film in multiple stages. For example, copper is used as a preferable wiring material resistant to electromigration. As a method of forming the wiring, a recess including a groove is formed in an interlayer insulating film, and after copper is embedded in the recess, an excess of copper is formed. A damascene process is employed in which the substrate is polished by a polishing method called CMP.

そして最近においてこのような銅配線技術を実施する上で、無電解めっき法を取り込むことが検討されている。無電解めっきは外部からの電解を使用せず、めっき液中に添加されている還元剤から電子を得て金属膜を形成する手法であり、凹部内に銅の埋め込みを行う前に凹部内に銅のシード層を形成する技術や、銅配線の上にバリア膜（例えば窒化シリコン、炭化シリコン、炭化窒化シリコンなどの膜）を形成する前にバリア膜と銅との密着層であるＣｏＷＰ（コバルトタングステンリン）などからなるめっき膜を形成する技術などに適用される。 Recently, it has been considered to incorporate an electroless plating method in implementing such copper wiring technology. Electroless plating is a technique in which electrons are obtained from the reducing agent added to the plating solution without forming electrolysis from the outside, and a metal film is formed. A technique for forming a copper seed layer, or CoWP (cobalt) which is an adhesion layer between a barrier film and copper before forming a barrier film (for example, a film of silicon nitride, silicon carbide, silicon carbonitride, etc.) on a copper wiring. The present invention is applied to a technique for forming a plating film made of tungsten phosphorus.

無電解めっきに関しては例えば周縁がチャックに保持された半導体ウエハ（以下ウエハという）を上下両面から温調用プレートにより加熱すると共に、所定温度例えば室温から６０℃までの間の設定温度に加熱された無電解めっき液を上部側プレートを介してウエハの表面に供給する手法が開示されている（特許文献１）。 With respect to electroless plating, for example, a semiconductor wafer (hereinafter referred to as a wafer) having a peripheral edge held by a chuck is heated from both the upper and lower surfaces by a temperature control plate and is heated to a predetermined temperature, for example, a set temperature between room temperature and 60 ° C. A method of supplying an electrolytic plating solution to the surface of a wafer via an upper plate is disclosed (Patent Document 1).

ところで無電解めっき液には電子の供給源である還元剤が含まれるため、特に加熱して使用する場合には、液中にて金属が析出するいわゆる液中析出が起こりやすくなる。液中析出が起こると、無電解めっき液の状態が変わってしまうため、ウエハ間において無電解めっき処理がばらついてしまい、例えばめっき膜の膜厚がばらついてしまうし、また析出粒子がパーティクル汚染の要因になる上、無電解めっき装置の配管の目詰まりを引き起こすおそれもある。特許文献１にはこのような無電解めっき液の不安定性には着眼されていない。 By the way, since the electroless plating solution contains a reducing agent which is an electron supply source, particularly when heated and used, so-called deposition in the solution in which a metal is deposited in the solution tends to occur. When the deposition in the liquid occurs, the state of the electroless plating solution changes, so that the electroless plating process varies between wafers, for example, the film thickness of the plating film varies, and the deposited particles are contaminated with particles. In addition to being a factor, it may cause clogging of the piping of the electroless plating apparatus. Patent Document 1 does not focus on the instability of such an electroless plating solution.

特開２００４−１０７７４７（図１及び段落００２６）JP 2004-107747 (FIG. 1 and paragraph 0026)

本発明はこのような事情の下になされたものであり、その目的は、無電解めっき液の状態の安定化を図り、基板の表面に対して安定しためっき処理をすることのできる無電解めっき装置を提供することにある。 The present invention has been made under such circumstances, and its purpose is to stabilize the state of the electroless plating solution and to perform stable plating treatment on the surface of the substrate. To provide an apparatus.

本発明は、基板を横向きの姿勢で保持する基板保持部と、
互いに混合されて無電解めっき液を形成する第１の薬液及び第２の薬液が夫々通流する第１の薬液供給路及び第２の薬液供給路と、
これら第１の薬液供給路及び第２の薬液供給路がその上流端にて合流し、その下流端に吐出口が形成された無電解めっき液の供給路と、
この無電解めっき液の供給路内の無電解めっき液の温度を調整する供給路温調手段と、
前記第１の薬液供給路及び第２の薬液供給路の各々における合流点の近傍に設けられた薬液用開閉手段と、
前記無電解めっき液の供給路における前記吐出口の近傍に設けられためっき液用開閉手段と、
前記基板に対して無電解めっきが行われている間に無電解めっき液の供給路内を満たしていた無電解めっき液を次の基板の表面に供給するために前記薬液用開閉手段及びめっき液用開閉手段を制御する制御手段と、を備え、
前記薬液用開閉手段とめっき液用開閉手段との間の供給路内の容積は、１枚の基板を無電解めっき処理するために必要な吐出量に相当することを特徴とする。この無電解めっき装置は、例えば第１の薬液及び第２の薬液の夫々の流量を調整するための手段を備えている
本発明は、第１の薬液と第２の薬液とをできるだけ無電解めっき処理の直前に混合しかつ薬液の使用量を極力抑える狙いがあり、一の基板の処理が開始されてから次の基板の処理に移る間に両薬液を混合し、そしてその混合液（無電解めっき液）は次の基板の処理において使い切ってしまうという発想に基づいている。従って薬液用開閉手段が第１の薬液供給路及び第２の薬液供給路の各々における合流点の近傍に設けられるという意味は、部品の構造上許容される範囲内で両薬液供給路の合流点にできるだけ近づけた構成をいう。合流点と各薬液用開閉手段との間の距離が大きいと、その間に満たされている液は薬液の拡散により両薬液の混じり合ったものになるが、その混合作用は薬液用開閉手段が閉じた後の静止状態に起こるので、十分混合されないまま基板上に供給されてめっきの均一性が低下してしまう。従って別の言い方をすれば、部品の構造やレイアウトの制限などから、各薬液用開閉手段が前記合流点から若干離れていたとしても、不十分な混合によるめっきの不均一性が起こらない範囲内であれば、「合流点の近傍」になる。 The present invention includes a substrate holding unit that holds the substrate in a lateral orientation;
A first chemical solution supply path and a second chemical solution supply path through which a first chemical solution and a second chemical solution, which are mixed with each other to form an electroless plating solution, respectively flow;
An electroless plating solution supply path in which the first chemical solution supply path and the second chemical liquid supply path merge at the upstream end thereof, and a discharge port is formed at the downstream end thereof;
Supply path temperature adjusting means for adjusting the temperature of the electroless plating solution in the supply path of the electroless plating solution;
Chemical liquid opening / closing means provided in the vicinity of the junction in each of the first chemical liquid supply path and the second chemical liquid supply path;
Opening / closing means for plating solution provided in the vicinity of the discharge port in the supply path of the electroless plating solution,
In order to supply the electroless plating solution that has filled the inside of the supply path of the electroless plating solution to the surface of the next substrate while the electroless plating is being performed on the substrate, the opening / closing means for chemical solution and the plating solution Control means for controlling the open / close means for use,
The volume in the supply path between the chemical solution opening / closing means and the plating solution opening / closing means corresponds to a discharge amount necessary for electroless plating of one substrate. The electroless plating apparatus includes, for example, means for adjusting the flow rates of the first chemical solution and the second chemical solution. The present invention is directed to electroless plating of the first chemical solution and the second chemical solution as much as possible. The aim is to mix just before processing and to reduce the amount of chemicals used as much as possible. Both chemicals are mixed between the start of the processing of one substrate and the processing of the next substrate. The plating solution is based on the idea that it will be used up in the next substrate processing. Therefore, the meaning that the opening / closing means for chemical liquid is provided in the vicinity of the merging point in each of the first chemical liquid supply path and the second chemical liquid supply path means that the merging point of both the chemical liquid supply paths is within the allowable range in the structure of the parts. A configuration that is as close as possible. If the distance between the junction and each chemical solution opening / closing means is large, the liquid filled between them will be a mixture of both chemical solutions due to the diffusion of the chemical solution, but the mixing action will close the chemical solution opening / closing means. Since this occurs in a resting state after that, it is supplied onto the substrate without being sufficiently mixed, and the uniformity of plating is lowered. Therefore, in other words, due to restrictions on the structure and layout of parts, even if each chemical switching means is slightly separated from the junction point, it is within a range where uneven plating due to insufficient mixing does not occur. If so, it becomes “near the confluence”.

また「薬液用開閉手段とめっき液用開閉手段との間の供給路内の容積（Ｖ１）は、１枚の基板を無電解めっき処理するために必要な吐出量（Ｖ２）に相当する」とはＶ１とＶ２とが揃っているという意味である。またＶ２とは、例えば基板表面が無電解めっきされるために当該表面に盛られる液量とめっき液用開閉手段から前記吐出口に至るまでの容積（液の体積）との合計量である。Ｖ１とＶ２との関係について述べると、Ｖ１がＶ２よりも大きい場合、１回の吐出量をＶ２にすると、めっき液供給路内にめっき液が残ってしまうし、また１回の吐出量をＶ１にすると、必要以上の量が吐出されるので、薬液が無駄になる。逆にＶ１がＶ２よりも小さい場合には、１回の吐出量をＶ２にすると、両薬液供給路の夫々に位置している第１の薬液及び第２の薬液がめっき液供給路に滞留せずに吐出されてしまうので、基板上のめっき液の均一性が低下する。このためＶ１とＶ２とが等しいことが理想であるが、設計上多少差が生じる場合も起こりうる。この場合でもめっき処理の均一性が確保され、またできるだけ薬液の無駄をなくす設計思想であれば、Ｖ１とＶ２とが「揃っている」ことになる。 “The volume (V1) in the supply path between the chemical solution opening / closing means and the plating solution opening / closing means corresponds to the discharge amount (V2) necessary for electroless plating of one substrate”. Means that V1 and V2 are aligned. V2 is the total amount of the amount of liquid accumulated on the surface of the substrate for electroless plating, for example, and the volume from the plating solution opening / closing means to the discharge port (volume of the solution). Describing the relationship between V1 and V2, when V1 is larger than V2, if the discharge amount of one time is V2, the plating solution remains in the plating solution supply path, and the discharge amount of one time is V1. In this case, since the amount more than necessary is discharged, the chemical solution is wasted. On the contrary, when V1 is smaller than V2, when the discharge amount per time is set to V2, the first chemical solution and the second chemical solution located in each of the two chemical solution supply paths stay in the plating solution supply path. Therefore, the uniformity of the plating solution on the substrate is lowered. For this reason, it is ideal that V1 and V2 are equal, but there may be a case where a difference occurs in design. Even in this case, V1 and V2 are “equal” if the design philosophy is to ensure the uniformity of the plating process and to eliminate as much chemical waste as possible.

この発明の好ましい態様の一つとしては、基板保持部に保持された基板の表面に対向すると共に、基板の有効領域よりも大きく形成され、下面に前記吐出口が形成された上部温調体と、この上部温調体を基板の表面との間に無電解めっき液を満たすための処理位置と、この処理位置から離れた待機位置との間で相対的に移動させる移動機構とを備えた構成を挙げることができる。この場合には、無電解めっき液の供給路の一部あるいは全部を上部温調体内に配置することができ、供給路温調手段の一部あるいは全部が上部温調体により兼用されることになる。 As one of preferred embodiments of the present invention, there is provided an upper temperature adjustment body that is opposed to the surface of the substrate held by the substrate holding portion, is formed larger than the effective area of the substrate, and has the discharge port formed on the lower surface. A structure including a moving mechanism for relatively moving the upper temperature adjusting body between the processing position for filling the electroless plating solution with the surface of the substrate and a standby position away from the processing position Can be mentioned. In this case, a part or all of the supply path for the electroless plating solution can be disposed in the upper temperature adjusting body, and a part or all of the supply path temperature adjusting means is shared by the upper temperature adjusting body. Become.

そして前記上部温調体はその内部が温調用流体の通流室として構成され、無電解めっき液と温調用流体との間で熱交換するために無電解めっき液の供給路の全部がこの通流室内に配置されることにより前記供給路温調手段を兼用するようにしてもよい。 The upper temperature adjusting body is configured as a flow chamber for the temperature adjusting fluid, and the entire supply path for the electroless plating solution is used for heat exchange between the electroless plating solution and the temperature adjusting fluid. The supply path temperature adjusting means may also be used by being arranged in the flow chamber.

更に本発明は、第１の薬液供給路及び第２の薬液供給路において、次に薬液用開閉手段を通って１枚の基板に使用される薬液が満たされている部位を温度調整する手段を設けるようにしてもよい。上部温調体の内部が温調用流体の通流室として構成される場合には、前記薬液が満たされている部位を温度調整する手段として、通流室を利用することができる。薬液の具体例を挙げておくと、第１の薬液は例えばめっき金属の金属塩を含む液であり、第２の薬液は例えば電子の供給源である還元剤を含む液である。 Furthermore, the present invention provides means for adjusting the temperature of a portion filled with a chemical solution used for one substrate through the chemical solution opening / closing means in the first chemical solution supply channel and the second chemical solution supply channel. You may make it provide. When the inside of the upper temperature control body is configured as a temperature control fluid flow chamber, the flow chamber can be used as means for adjusting the temperature of the portion filled with the chemical solution. For example, the first chemical liquid is a liquid containing a metal salt of a plating metal, and the second chemical liquid is a liquid containing a reducing agent that is an electron supply source.

本発明によれば、第１の薬液供給路及び第２の薬液供給路の各々における合流点の近傍に薬液用開閉手段を設けると共に、無電解めっき液の供給路における吐出口の近傍にめっき液用開閉手段を設け、これら開閉手段により挟まれる供給路の容積を、概ね１回のめっき処理に必要な吐出量に対応させている。従って基板のめっき処理が開始され、当該基板の次の基板の無電解めっき処理が開始されるまでの間だけ両薬液が混合されるので、言い換えれば無電解めっき処理が行われる直前に薬液が混合されるので、無電解めっき液が不安定な状態で保持されることが極力避けられ、例えば液中析出を防ぐことができる。この結果、常に同等の状態の無電解めっき液を基板表面に供給することができるので安定した無電解めっき処理を行うことができ、基板間における膜厚及び膜質の均一性が向上する。 According to the present invention, the chemical solution opening / closing means is provided in the vicinity of the junction in each of the first chemical solution supply channel and the second chemical solution supply channel, and the plating solution is provided in the vicinity of the discharge port in the electroless plating solution supply channel. The opening / closing means is provided, and the volume of the supply path sandwiched between these opening / closing means is made to correspond to the discharge amount necessary for one plating process. Therefore, both chemical solutions are mixed only until the plating process of the substrate is started and the electroless plating process of the next substrate is started. In other words, the chemical solution is mixed immediately before the electroless plating process is performed. Therefore, it is avoided as much as possible that the electroless plating solution is held in an unstable state, and for example, precipitation in the solution can be prevented. As a result, since an electroless plating solution in an equivalent state can always be supplied to the substrate surface, a stable electroless plating process can be performed, and the film thickness and film quality uniformity between the substrates can be improved.

図１は、本発明の無電解めっき装置の実施の形態の全体構成図を示す図である。図１中１１は、上部が開口している扁平な円筒状の基板保持部をなすウエハチャックであり、このウエハチャック１１の上端の周縁部には基板であるウエハＷの周縁部を保持する段部１２が全周に亘って形成されている。このウエハチャック１１の中央部には筒状の回転軸１３が設けられており、この回転軸１３は回転駆動部例えば中空モータ１４に接続されている。この中空モータ１４によりウエハチャック１１はウエハＷを支持した状態で鉛直軸周りに回転可能なように構成されている。中空モータ１４はベース１５に固定され、このベース１５は、傾斜機構１６に取り付けられていて傾斜できるようになっている。 FIG. 1 is a diagram showing an overall configuration diagram of an embodiment of an electroless plating apparatus of the present invention. In FIG. 1, reference numeral 11 denotes a wafer chuck that forms a flat cylindrical substrate holding portion having an open top, and a step of holding the peripheral portion of the wafer W as a substrate at the peripheral portion of the upper end of the wafer chuck 11. The part 12 is formed over the entire circumference. A cylindrical rotary shaft 13 is provided at the center of the wafer chuck 11, and the rotary shaft 13 is connected to a rotary drive unit such as a hollow motor 14. The wafer chuck 11 is configured to be rotatable about the vertical axis while the wafer W is supported by the hollow motor 14. The hollow motor 14 is fixed to a base 15, and this base 15 is attached to a tilt mechanism 16 so that it can tilt.

ウエハチャック１１の外側には、当該ウエハチャック１１を囲むように液受け用のカップ体２１が設けられており、カップ体２１は図示しない昇降機構によりベース１５に対して昇降できるように構成されている。前記カップ体２１の側周面の上端部は内方側に屈曲して、ウエハＷを回転させたときに振り切られる液を跳ね返すようになっている。またカップ体２１の底面中央部には開口部２２が形成されていて、この開口部２２内に前記回転軸１３が貫通していると共に、前記底面の周縁に近い部位にはウエハＷからこぼれ落ちた液をドレインとして排出するためのドレイン排出部２３が設けられている。またウエハチャック１１における中央から外れた底面においても図では見えない孔部が形成されていて、ウエハチャック１１内にこぼれ落ちた液がカップ体２１内に流れ落ちるようになっている。 A liquid receiving cup body 21 is provided outside the wafer chuck 11 so as to surround the wafer chuck 11, and the cup body 21 is configured to be moved up and down with respect to the base 15 by a lifting mechanism (not shown). Yes. The upper end portion of the side peripheral surface of the cup body 21 is bent inward so that the liquid sprinkled off when the wafer W is rotated rebounds. An opening 22 is formed at the center of the bottom surface of the cup body 21, and the rotating shaft 13 passes through the opening 22, and the portion near the periphery of the bottom surface spills from the wafer W. A drain discharge portion 23 is provided for discharging the liquid as a drain. Further, a hole portion that is not visible in the drawing is formed on the bottom surface of the wafer chuck 11 that is off the center, so that the liquid spilled into the wafer chuck 11 flows into the cup body 21.

前記ウエハチャック１１の上方側には、このウエハチャック１１に保持されるウエハＷの表面に対向するように上部温調体３が設けられている。この上部温調体３は、外形が扁平な円柱状でウエハＷよりも少し大きいサイズに作られていると共に、移動機構である昇降機構３０により、ウエハＷに対して無電解めっき液を供給する処理位置とこの処理位置から上方に離れた待機位置との間で昇降できるように構成されている。上部温調体４はウエハＷの有効領域（集積回路の形成領域）より大きければよいが、近年ではウエハＷの周縁に可成り近いところまで集積回路を形成することから、ウエハＷのサイズと同じかあるいはそれよりも大きいことが好ましい。またウエハチャック１１内には下部温調体２４が配置されており、この下部温調体２４はウエハチャック１１に保持されるウエハＷの裏面に対向して、前記回転軸１３内を貫通している支持軸２５を介して図示しない昇降機構により昇降できるように構成されている。上部温調体３及び下部温調体２４は例えば抵抗加熱体からなるヒータを備えた例えばセラミックスからなるプレートにより構成されるが、内部に熱媒体が通流するプレートであってもよい。 An upper temperature adjusting body 3 is provided above the wafer chuck 11 so as to face the surface of the wafer W held by the wafer chuck 11. The upper temperature adjusting body 3 is a cylindrical shape having a flat outer shape and is made slightly larger than the wafer W, and supplies an electroless plating solution to the wafer W by an elevating mechanism 30 that is a moving mechanism. It is configured to be able to move up and down between the processing position and a standby position away from the processing position. The upper temperature control body 4 only needs to be larger than the effective area (integrated circuit formation area) of the wafer W. However, in recent years, the integrated circuit is formed as close as possible to the periphery of the wafer W. Or larger than that. A lower temperature adjusting body 24 is disposed in the wafer chuck 11, and the lower temperature adjusting body 24 passes through the rotating shaft 13 so as to face the back surface of the wafer W held by the wafer chuck 11. It can be moved up and down by a lifting mechanism (not shown) via a supporting shaft 25. The upper temperature adjusting body 3 and the lower temperature adjusting body 24 are constituted by, for example, a plate made of ceramics provided with a heater made of a resistance heating body, for example, but may be a plate through which a heat medium flows.

下部温調体２４の下面の中央部には、温調水例えば純水の供給路である純水供給管２６の一端側が挿入されており、この純水供給管２６は支持軸２５内に配管されていて、その他端側は、バルブ２７及びポンプ２８を介して純水タンク２９に接続されている。なおこの純水は裏面側リンス液としての役割も有している。 One end side of a pure water supply pipe 26 that is a supply path of temperature-controlled water, for example, pure water, is inserted in the central portion of the lower surface of the lower temperature adjusting body 24, and the pure water supply pipe 26 is piped inside the support shaft 25. The other end is connected to a pure water tank 29 through a valve 27 and a pump 28. This pure water also has a role as a back surface rinsing liquid.

上部温調体３の昇降機構３０及び下部温調体２４の図示しない昇降機構は、ベース１５に固定されており、従って傾斜機構１６により上部温調体３、ウエハＷ及び下部温調体２４が一体的に傾くこととなる。これらを傾斜させる目的は、後述のように上部温調体３とウエハＷとの間に無電解めっき液などの処理液を満たしたときにその中に混入する気泡を上部側に移動させて取り除くことにあるが、この実施の形態では気泡が入りにくい構造になっているため、傾斜機構１６は設けなくてもよい。 The raising / lowering mechanism 30 of the upper temperature adjusting body 3 and the raising / lowering mechanism (not shown) of the lower temperature adjusting body 24 are fixed to the base 15, so that the upper temperature adjusting body 3, the wafer W and the lower temperature adjusting body 24 are moved by the tilt mechanism 16. It will be tilted together. The purpose of inclining them is to remove the bubbles mixed in the upper temperature adjusting body 3 and the wafer W when the processing liquid such as the electroless plating solution is filled between them as described later. In particular, in this embodiment, since the air bubbles are difficult to enter, the tilting mechanism 16 need not be provided.

次に図２を参照しながら無電解めっき液の供給系に関して説明する。上部温調体３の中央部には、例えば管体からなる無電解めっき液の供給路４１の一端側が配置されており、その下端は上部温調体３の下面と面一である無電解めっき液の吐出口４２を形成している。無電解めっき液供給路４１における上部温調体３の上部側には、当該供給路４１内の液を給断するためのめっき液用開閉バルブに相当するバルブ４３が設けられていると共に、無電解めっき液供給路４１の上流側は第１の薬液供給路５と第２の薬液供給路６とに分岐されている。つまり無電解めっき液供給路４１の上流端において第１の薬液供給路５と第２の薬液供給路６とが合流している。無電解めっき液供給路４１は、供給路温調手段４４により囲まれていて当該供給管４１内の無電解めっき液が所定の温度例えば室温から６０℃の範囲で選択された温度に設定されるように構成されている。供給路温調手段４４はこの例では筒状のケース体４５内に熱媒体供給路４６及び熱媒体排出路４７を介して熱媒体例えば純水が通流するように構成されている。バルブ４３についても前記供給路温調手段４４の一部をなすヒータ４８が周囲に設けられていてバルブ４３内の無電解めっき液の温調を行うようになっている。 Next, an electroless plating solution supply system will be described with reference to FIG. One end side of an electroless plating solution supply path 41 made of, for example, a tube is disposed at the center of the upper temperature adjustment body 3, and the lower end of the upper temperature adjustment body 3 is flush with the lower surface of the upper temperature adjustment body 3. A liquid discharge port 42 is formed. On the upper side of the upper temperature adjusting body 3 in the electroless plating solution supply path 41, there is provided a valve 43 corresponding to a plating solution on-off valve for supplying and disconnecting the solution in the supply path 41, and no The upstream side of the electrolytic plating solution supply path 41 is branched into a first chemical solution supply path 5 and a second chemical solution supply path 6. That is, the first chemical solution supply path 5 and the second chemical solution supply path 6 merge at the upstream end of the electroless plating solution supply path 41. The electroless plating solution supply path 41 is surrounded by the supply path temperature adjusting means 44, and the electroless plating solution in the supply pipe 41 is set to a predetermined temperature, for example, a temperature selected in the range of room temperature to 60 ° C. It is configured as follows. In this example, the supply path temperature adjusting means 44 is configured such that a heat medium such as pure water flows through a cylindrical case body 45 via a heat medium supply path 46 and a heat medium discharge path 47. The valve 43 is also provided with a heater 48 that forms a part of the supply path temperature adjusting means 44 to adjust the temperature of the electroless plating solution in the valve 43.

第１の薬液供給路５と第２の薬液供給路６とは、互いに混合されて無電解めっき液を形成する第１の薬液及び第２の薬液が夫々通流するための供給路であり、合流点（無電解めっき液供給路４１の上端）の近傍には、薬液用開閉手段であるバルブ５１及び６１が設けられている。これらバルブ５１、６１は部品のレイアウト上許容できる範囲でできるだけ合流点に接近させて配置されている。その理由は、薬液が次のウエハＷの処理に対して待機している静止状態の間にできるだけ均一に拡散混合されるようにするためである。 The first chemical liquid supply path 5 and the second chemical liquid supply path 6 are supply paths through which the first chemical liquid and the second chemical liquid, which are mixed with each other to form an electroless plating solution, respectively flow. In the vicinity of the junction (the upper end of the electroless plating solution supply path 41), valves 51 and 61 serving as chemical solution opening / closing means are provided. These valves 51 and 61 are arranged as close to the junction as possible within the allowable range of the parts layout. The reason is that the chemical solution is diffused and mixed as uniformly as possible during the stationary state in which the chemical solution is waiting for processing of the next wafer W.

第１の薬液供給路５は上流側から薬液供給源５２、ポンプ５３及び流量調整部５４がこの順に設けられており、第２の薬液供給路６は上流側から薬液供給源６２、ポンプ６３及び流量調整部６４がこの順に設けられている。第１の薬液は、無電解めっき膜を形成する成分を含む金属塩と、強アルカリ性下において金属イオンが水酸化物として沈殿しないように金属を錯体化するための錯化剤と、液のｐＨを調整するためのｐＨ調整剤とを含んでいる。 The first chemical solution supply path 5 is provided with a chemical solution supply source 52, a pump 53, and a flow rate adjusting unit 54 in this order from the upstream side, and the second chemical solution supply path 6 is provided with a chemical solution supply source 62, a pump 63, and A flow rate adjusting unit 64 is provided in this order. The first chemical solution includes a metal salt containing a component that forms an electroless plating film, a complexing agent for complexing the metal so that metal ions do not precipitate as hydroxide under strong alkalinity, and the pH of the solution And a pH adjuster for adjusting the pH.

金属塩は、膜の成分が合金の場合にはその合金の成分を含む第１の金属塩及び第２の金属塩からなる。第１の薬液の成分に関して具体例を挙げると、第１の金属塩として例えば硫酸コバルト,塩化コバルト,硫酸ニッケル,塩化ニッケル、第２の金属塩としては例えばタングステン酸，タングステン酸アンモニウムを選択することができ、また錯化剤としては例えばクエン酸、クエン酸ナトリウム，ｐＨ調整剤として水酸化ナトリウム，ＴＭＡＨ（テトラメチルアンモニウムハイドロオキサイド）を選択することができる。 When the component of the film is an alloy, the metal salt includes a first metal salt and a second metal salt containing the alloy component. As specific examples of the components of the first chemical solution, for example, cobalt sulfate, cobalt chloride, nickel sulfate, nickel chloride are selected as the first metal salt, and for example, tungstic acid and ammonium tungstate are selected as the second metal salt. As the complexing agent, for example, citric acid, sodium citrate, and sodium hydroxide and TMAH (tetramethylammonium hydroxide) can be selected as the pH adjusting agent.

第２の薬液は、金属イオンを触媒的に還元析出させるための還元剤、液のｐＨを調整するためのｐＨ調整剤を含んでいる。還元剤としては例えばＤＭＡＢ（ジメチルアミンボラン）などを挙げることができる。第１の薬液及び第２の薬液は例えば室温で貯留されており、ｐＨ１０に維持されている。なお、列記した成分は一例であり、必ずしもこれらの成分を用いなくてもよい。 The second chemical liquid contains a reducing agent for catalytically reducing and depositing metal ions and a pH adjusting agent for adjusting the pH of the liquid. Examples of the reducing agent include DMAB (dimethylamine borane). The first chemical solution and the second chemical solution are stored at room temperature, for example, and are maintained at pH 10. Note that the listed components are examples, and these components are not necessarily used.

これら第１の薬液及び第２の薬液は夫々流量調整部５４及び６４により所定の混合比になるように、例えば第１の薬液：第２の薬液が９：１の割合になるように、また１枚のウエハＷを処理するための無電解めっき液の吐出量が例えば５０ｃｃとなるように流量が調整される。 The first chemical solution and the second chemical solution are adjusted to have a predetermined mixing ratio by the flow rate adjusting units 54 and 64, respectively, for example, the ratio of the first chemical solution: the second chemical solution is 9: 1, and The flow rate is adjusted so that the discharge amount of the electroless plating solution for processing one wafer W is, for example, 50 cc.

ここで前記薬液用開閉手段であるバルブ５１及び６１とめっき液用開閉手段であるバルブ４３との間の無電解めっき液供給路４１内の容積Ｖ１は、１枚のウエハＷを無電解めっき処理するために必要な吐出量Ｖ２（この例では５０ｃｃ）に相当するように設計されている。Ｖ１とＶ２との関係については、課題を解決するための手段の項目にて詳述したように、例えば上記の吐出量Ｖ２は、バルブ４３の下流側に液体が存在しない状態で、ウエハＷと上部温調体３との間に無電解めっき液を満たしたときにバルブ４３を通過する液量（１枚のウエハＷの処理に必要な液量）である。言い換えればウエハＷと上部温調体３との間の容積とバルブ４３から吐出口４２までの容積との合計量に相当する。この場合バルブ４３から吐出口４２までの間の無電解めっき液は無駄になるので、バルブ４３はできるだけ吐出口４２に近づけることが好ましく、例えば上部温調体３内に圧電素子を用いて流路を開閉するタイプのバルブを設けるようにしてもよい。 Here, the volume V1 in the electroless plating solution supply path 41 between the valves 51 and 61 serving as the chemical solution opening and closing means and the valve 43 serving as the plating solution opening and closing means is the electroless plating treatment of one wafer W. It is designed to correspond to the discharge amount V2 (50 cc in this example) necessary for this. Regarding the relationship between V1 and V2, as described in detail in the section of means for solving the problem, for example, the discharge amount V2 is the same as that of the wafer W in the state where no liquid exists on the downstream side of the valve 43. This is the amount of liquid that passes through the valve 43 when the electroless plating solution is filled with the upper temperature adjusting body 3 (the amount of liquid necessary for processing one wafer W). In other words, this corresponds to the total amount of the volume between the wafer W and the upper temperature adjusting body 3 and the volume from the valve 43 to the discharge port 42. In this case, since the electroless plating solution between the valve 43 and the discharge port 42 is wasted, the valve 43 is preferably as close to the discharge port 42 as possible. For example, a flow path using a piezoelectric element in the upper temperature control body 3 is used. A valve that opens and closes may be provided.

上部温調体３における無電解めっき液供給路４１の近傍には、洗浄液である純水の供給路７１が配置され、この純水供給路７１の下流端は上部温調体３の下面に開口する吐出口７２として形成されると共に上流端には純水タンク７３が設けられている。純水供給路７１の下流端は無電解めっき液供給路４１におけるバルブ４３と吐出口４２との間に開口するようにしてもよい。７４はポンプであり、７５は純水供給路７１における純水の給断を行うバルブである。またこの無電解めっき装置は、例えばコンピュータからなる制御部１００を備えており、この制御部１００は、ポンプ５３、６３、７３及び各バルブ４３、５１、６１、７５等の動作を制御するためのシーケンスプログラムを備えている。 A supply path 71 of pure water, which is a cleaning liquid, is disposed in the vicinity of the electroless plating solution supply path 41 in the upper temperature adjustment body 3, and a downstream end of the pure water supply path 71 is open to the lower surface of the upper temperature adjustment body 3. A pure water tank 73 is provided at the upstream end. The downstream end of the pure water supply path 71 may be opened between the valve 43 and the discharge port 42 in the electroless plating solution supply path 41. 74 is a pump, and 75 is a valve for supplying and disconnecting pure water in the pure water supply passage 71. In addition, the electroless plating apparatus includes a control unit 100 including, for example, a computer. The control unit 100 controls operations of the pumps 53, 63, 73, the valves 43, 51, 61, 75, and the like. A sequence program is provided.

ここで図１に戻って、この無電解めっき装置は、ウエハチャック１１に保持されたウエハＷの上方における流体の供給位置と待機位置との間で移動自在な複数のノズルを備えている。図１では便宜上２つのノズル１７、１８を示してある。例えばノズル１７は、無電解めっき液の前に置換めっき液をウエハＷの表面に供給するためのものであり、図示していない配管を通じて置換めっき液の供給源に接続されている。またノズル１８は乾燥用ガス例えば不活性ガスを供給するためのものであり、図示していない配管を通じて乾燥用ガスの供給源に接続されている。これらノズル１７、１８は、例えばウエハＷの半径以上の長さの例えばスリット状の吐出口を備え、図示しない駆動機構により昇降自在かつ横方向に移動自在例えば旋回自在に構成されている。 Here, referring back to FIG. 1, the electroless plating apparatus includes a plurality of nozzles movable between a fluid supply position and a standby position above the wafer W held by the wafer chuck 11. In FIG. 1, two nozzles 17 and 18 are shown for convenience. For example, the nozzle 17 is for supplying a replacement plating solution to the surface of the wafer W before the electroless plating solution, and is connected to a supply source of the replacement plating solution through a pipe (not shown). The nozzle 18 is for supplying a drying gas such as an inert gas, and is connected to a drying gas supply source through a pipe (not shown). These nozzles 17 and 18 are provided with, for example, slit-shaped ejection openings having a length equal to or larger than the radius of the wafer W, and are configured to be movable up and down and laterally movable by a driving mechanism (not shown).

次に上述実施の形態の作用について説明する。先ず上部温調体３を待機位置にて待機させると共にウエハチャック１１を下降させ、図示しない搬送手段によりウエハＷの表面を吸着してウエハチャック１１の上方まで搬送し、ウエハチャック１１を上昇させて搬送手段のウエハＷをウエハチャック１１に受け渡す（図１の状態）。またウエハＷの表面は図３（ａ）に示すように例えば層間絶縁膜３０１の凹部に銅配線３０２が埋め込まれている状態である。３０３は凹部内の銅が絶縁膜３０１に拡散しないようにするためのバリア膜である。 Next, the operation of the above embodiment will be described. First, the upper temperature control body 3 is made to stand by at the standby position, and the wafer chuck 11 is lowered, the surface of the wafer W is sucked by the transfer means (not shown) and transferred to the upper side of the wafer chuck 11, and the wafer chuck 11 is raised. The wafer W of the transfer means is transferred to the wafer chuck 11 (state shown in FIG. 1). Further, as shown in FIG. 3A, the surface of the wafer W is in a state in which, for example, a copper wiring 302 is embedded in a recess of the interlayer insulating film 301. Reference numeral 303 denotes a barrier film for preventing copper in the recess from diffusing into the insulating film 301.

続いて図４（ａ）に示すように例えばノズル１７がウエハＷ上に移動し、ウエハチャック１１を介してウエハＷを回転させながら前処理液をウエハＷ上に供給して前処理液のパドルを形成する。この前処理液は例えばパラジウム置換めっきを行うための置換めっき液であり、この置換めっき液は、硫酸パラジウムあるいは塩化パラジウムなどからなるパラジウム塩を硫酸や塩酸などの酸溶液に溶解させたものを用いることができる。この置換めっき液は例えば室温から６０℃の範囲内で選択された温度に温調されてウエハＷ表面に供給され、これにより図３（ｂ）に示すように銅配線３０２と置換めっき液との界面においてパラジウムよりも酸化還元電位が卑な銅がパラジウムに電子を受け渡して溶解し、電子を受け取ったパラジウムからなる触媒層３０４が銅配線３０２の表面に選択的に析出する。この触媒層３０４は、後工程における無電解めっき処理の触媒として作用するものであるが、無電解めっき液によっては触媒を必要としないものもあり、その場合ノズル１７から有機酸溶液をウエハＷに供給して前処理が行われる場合もある。その後、図４（ｂ）に示すようにウエハＷを回転させながらノズル１８から洗浄液例えば純水をウエハＷ上に供給し、上記の前処理液を除去する。 Subsequently, as shown in FIG. 4A, for example, the nozzle 17 moves onto the wafer W, and the pretreatment liquid is supplied onto the wafer W while rotating the wafer W via the wafer chuck 11 to paddle the pretreatment liquid. Form. This pretreatment liquid is, for example, a displacement plating liquid for performing palladium displacement plating, and this displacement plating solution uses a palladium salt made of palladium sulfate or palladium chloride dissolved in an acid solution such as sulfuric acid or hydrochloric acid. be able to. This replacement plating solution is temperature-controlled at a temperature selected within a range of room temperature to 60 ° C., for example, and supplied to the surface of the wafer W, whereby the copper wiring 302 and the replacement plating solution are connected as shown in FIG. Copper having a lower oxidation-reduction potential than palladium at the interface delivers electrons to palladium and dissolves, and a catalyst layer 304 made of palladium that has received the electrons is selectively deposited on the surface of the copper wiring 302. This catalyst layer 304 acts as a catalyst for electroless plating treatment in a later step, but some electroless plating solutions do not require a catalyst. In this case, the organic acid solution is transferred from the nozzle 17 to the wafer W. In some cases, pre-processing is performed after the supply. Thereafter, as shown in FIG. 4B, a cleaning liquid such as pure water is supplied onto the wafer W from the nozzle 18 while rotating the wafer W, and the pretreatment liquid is removed.

しかる後、ノズル１８をウエハＷの上方から退避させ、上部温調体３を下降させてその下面とウエハＷの表面との距離が例えば０．１ｍｍ〜２ｍｍとなる位置に設定する。このとき下部温調体４も上昇させてウエハＷの裏面との距離が例えば０．１ｍｍ〜２ｍｍとなる位置に設定する。そして温調液である純水はポンプ２８により送水されると、純水供給管２６を介して下部温調体２４内を通って予め設定された設定温度に加熱される。 Thereafter, the nozzle 18 is retracted from above the wafer W, the upper temperature adjusting body 3 is lowered, and the distance between its lower surface and the surface of the wafer W is set to a position where it is, for example, 0.1 mm to 2 mm. At this time, the lower temperature adjustment body 4 is also raised and set to a position where the distance from the back surface of the wafer W is, for example, 0.1 mm to 2 mm. Then, when the pure water as the temperature adjusting liquid is fed by the pump 28, it is heated to a preset temperature through the lower temperature adjusting body 24 through the pure water supply pipe 26.

加熱された純水は下部温調体２４とウエハＷの裏面との間の隙間に満たされながらウエハチャック１１内に流れ落ち、図では見えない孔部を介してカップ２１内に流れ落ちる。また下部温調体２４の上面も設定温度に維持されようとするので、ウエハＷが裏面側から加熱されてめっき処理温度に維持されようとする。このようにしてウエハＷを所定時間例えば１０秒加熱した後、図２に示すポンプ５３、６３を駆動すると共に、バルブ４３、５１及び６１を同時に開き、設定時間を経過後にポンプ５３、６３を停止すると共に、バルブ４３、５１及び６１を同時に閉じる。このようにバルブの開閉動作を同時に行うことで薬液が逆流することを防止できる。そしてこの設定時間は、無電解めっき液供給路４１におけるバルブ４３、５１及び６１の間の液が全部吐出されるに必要な時間であり、これにより図５（ａ）に示すように、無電解めっき液供給路４１内の無電解めっき液がウエハＷと上部温調体３との間に例えば３０〜１００ｍｌ／分の流量で供給されて満たされる。 The heated pure water flows down into the wafer chuck 11 while being filled in a gap between the lower temperature adjusting body 24 and the back surface of the wafer W, and then flows into the cup 21 through a hole that is not visible in the drawing. Further, since the upper surface of the lower temperature adjusting body 24 is also maintained at the set temperature, the wafer W is heated from the back surface side and is maintained at the plating processing temperature. In this way, after heating the wafer W for a predetermined time, for example, 10 seconds, the pumps 53 and 63 shown in FIG. 2 are driven and the valves 43, 51 and 61 are simultaneously opened, and the pumps 53 and 63 are stopped after the set time has elapsed. At the same time, the valves 43, 51 and 61 are closed simultaneously. Thus, it can prevent that a chemical | medical solution flows backward by performing the opening / closing operation | movement of a valve | bulb simultaneously. The set time is a time required for discharging all of the liquid between the valves 43, 51 and 61 in the electroless plating solution supply path 41. As a result, as shown in FIG. The electroless plating solution in the plating solution supply path 41 is supplied and filled between the wafer W and the upper temperature adjusting body 3 at a flow rate of, for example, 30 to 100 ml / min.

この無電解めっき液は当該ウエハＷよりも一つ前のウエハＷに対して無電解めっき液を供給するときに第１の薬液供給路５及び第２の薬液供給路６から夫々第１の薬液及び第２の薬液がバルブ５１、６１を介して合流して無電解めっき液供給路４１内に流入し、当該ウエハＷに対して供給されるまでの間に拡散により混合されて無電解めっき液とされかつ供給路温調手段４４により温調され活性な状態にされたものである。また上部温調体３も例えば無電解めっき液の設定温度と同じ温度に加熱されており、このためウエハＷは表裏両面から温度調整されながら、無電解めっき処理が行われることになる。即ち前工程にてウエハＷの表面に析出したパラジウムが触媒として作用して無電解めっき液と銅との間で反応が起こり、図３（ｃ）に示すように銅配線３０２の表面に選択的にリン（Ｐ）を含む合金からなる例えばＮｉＰ,ＣｏＷＰ,ＮｉＰ,ＣｏＰなどの例えば膜厚１００〜２００Åの密着層をなす無電解めっき膜３０５が形成される。 The electroless plating solution is supplied from the first chemical solution supply path 5 and the second chemical solution supply path 6 when the electroless plating solution is supplied to the wafer W preceding the wafer W, respectively. And the second chemical solution merges through the valves 51 and 61 and flows into the electroless plating solution supply path 41 and is mixed by diffusion before being supplied to the wafer W. The temperature is adjusted by the supply path temperature adjusting means 44 and is activated. The upper temperature adjusting body 3 is also heated to, for example, the same temperature as the set temperature of the electroless plating solution. Therefore, the electroless plating process is performed while the temperature of the wafer W is adjusted from both the front and back surfaces. That is, the palladium deposited on the surface of the wafer W in the previous step acts as a catalyst to cause a reaction between the electroless plating solution and copper, and selectively occurs on the surface of the copper wiring 302 as shown in FIG. Then, an electroless plating film 305 is formed which forms an adhesion layer having a thickness of, for example, 100 to 200 mm, such as NiP, CoWP, NiP, or CoP, which is made of an alloy containing phosphorus (P).

そして今回の無電解めっき液の吐出により無電解めっき液供給路４１におけるバルブ５１、６１、４３により挟まれる領域の無電解めっき液が押し出されたが、同時にバルブ５１、６１を介して夫々新たな第１の薬液及び第２の薬液が既述のように流量調整部５４、６４にて９：１の流量比に調整されて当該領域内にその領域を満たす液量（Ｖ１）だけ流入する。 Then, the electroless plating solution in the region sandwiched by the valves 51, 61, 43 in the electroless plating solution supply path 41 is pushed out by the discharge of the electroless plating solution this time. As described above, the first chemical solution and the second chemical solution are adjusted to a flow rate ratio of 9: 1 by the flow rate adjusting units 54 and 64 and flow into the region by a liquid amount (V1) that satisfies the region.

このときウエハＷの裏面側には洗浄水を兼ねた純水が供給されているので、この純水によりいわゆるバックリンスがなされ、無電解めっき液がウエハＷの裏面側に回り込むことを防止ししている。なお処理中にウエハチャック１１を介してウエハＷを回転させ、ウエハＷの面内温度均一性をより高めるようにしてもよい。この工程においては、傾斜機構１６を用いてウエハＷ、上部温調体３及び下部温調体２４を傾斜させて前記隙間に入り込んだ気泡を無電解めっき液から取り除くようにしてもよい。こうした処理は、無電解めっき液と銅との反応によりガスが発生する場合などにおいて有効である。 At this time, pure water that also serves as cleaning water is supplied to the back surface side of the wafer W, so that this pure water causes so-called back rinse, and prevents the electroless plating solution from entering the back surface side of the wafer W. ing. Note that the wafer W may be rotated through the wafer chuck 11 during processing to further improve the in-plane temperature uniformity of the wafer W. In this step, the wafer W, the upper temperature adjustment body 3 and the lower temperature adjustment body 24 may be inclined using the inclination mechanism 16 to remove bubbles that have entered the gap from the electroless plating solution. Such treatment is effective when gas is generated by the reaction between the electroless plating solution and copper.

次いで図２に示す純水供給路７１のバルブ７５を開いて、図５（ｂ）に示すように吐出口７２から純水をウエハＷと上部温調体３との間に供給し、ウエハＷの表面の無電解めっき液を純水により置換する。しかる後、上部温調体３を上昇させ、ノズル１７、１８により代表して示されるノズル群の中のノズル（便宜上１８を付してある）を用いて、図６（ａ）に示すように後洗浄液を回転しているウエハＷ上に供給し、ウエハＷの表面を後洗浄する。このときにおいてもウエハＷの裏面側には純水がバックリンスとして供給されている。後洗浄は線間リーク電流減少のために行われ、後洗浄液としては例えば有機酸およびフッ酸系水溶液が用いられる。なお無電解めっき処理の後に行われる純水の供給は、上部温調体３を上昇させてノズル１８により行ってもよい。 Next, the valve 75 of the pure water supply passage 71 shown in FIG. 2 is opened, and pure water is supplied from the discharge port 72 between the wafer W and the upper temperature regulator 3 as shown in FIG. The electroless plating solution on the surface of is replaced with pure water. Thereafter, the upper temperature adjustment body 3 is raised, and nozzles (indicated by 18 for convenience) in the nozzle group represented by the nozzles 17 and 18 are used as shown in FIG. A post-cleaning liquid is supplied onto the rotating wafer W, and the surface of the wafer W is post-cleaned. Also at this time, pure water is supplied to the back side of the wafer W as a back rinse. Post-cleaning is performed to reduce the leakage current between lines, and organic acid and hydrofluoric acid aqueous solution are used as the post-cleaning liquid. The supply of pure water performed after the electroless plating process may be performed by the nozzle 18 with the upper temperature adjusting body 3 raised.

続いて既述のノズル群のノズル（便宜上１８を付してある）から洗浄液である純水を回転しているウエハＷの表面に供給し、その後、洗浄液の吐出を止めて図６（ｂ）に示すようにウエハＷを高速回転させて乾燥させる。このとき既述のノズル群のノズルからウエハＷの表面に不活性ガスなどの乾燥ガスを吹き付けて乾燥を促進するようにしてもよい。こうして一連の工程が終了した後、図示しない搬送手段によりウエハＷの表面を吸着してウエハチャック１１から当該ウエハＷを搬出する。 Subsequently, pure water, which is a cleaning liquid, is supplied from the nozzles of the nozzle group described above (for the sake of convenience) to the surface of the rotating wafer W, and then the discharge of the cleaning liquid is stopped and FIG. As shown in FIG. 2, the wafer W is rotated at a high speed and dried. At this time, drying may be accelerated by spraying a dry gas such as an inert gas from the nozzles of the nozzle group described above onto the surface of the wafer W. After the series of steps is completed in this way, the surface of the wafer W is sucked by a transfer means (not shown), and the wafer W is unloaded from the wafer chuck 11.

上述の実施の形態によれば、第１の薬液供給路５及び第２の薬液供給路６の各々における合流点の近傍に薬液用開閉手段であるバルブ５１、６１を設けると共に、無電解めっき液供給路４１における吐出口４２の近傍にめっき液用開閉手段であるバルブ４３を設け、これらバルブ４３、５１、６１により挟まれる供給路４１の容積を、ウエハＷの１枚のめっき処理に必要な吐出量に対応させている。従ってウエハＷのめっき処理が開始され、当該ウエハＷの次のウエハＷの無電解めっき処理が開始されるまでの間だけ両薬液が混合されるので、両薬液が混合されている状態に置かれている時間が短く、いわば無電解めっき処理が行われる直前に両薬液が混合されるといえる。このため無電解めっき液が不安定な状態で保持されることが極力避けられ、液中析出を防ぐことができる。この結果、無電解めっき液が安定している状態でウエハＷ表面に対して無電解めっき処理を行うことができ、ウエハＷ間における膜厚及び膜質の均一性が向上する。また粒子の析出のおそれがないのでパーティクル汚染や配管の目詰まりを引き起こすこともない。 According to the above-described embodiment, the valves 51 and 61 serving as the chemical solution opening / closing means are provided in the vicinity of the junction in each of the first chemical solution supply path 5 and the second chemical solution supply path 6 and the electroless plating solution. A valve 43 serving as a plating solution opening / closing means is provided in the supply path 41 in the vicinity of the discharge port 42, and the volume of the supply path 41 sandwiched between the valves 43, 51, 61 is necessary for one plating process of the wafer W. It corresponds to the discharge amount. Therefore, since both the chemicals are mixed until the plating process of the wafer W is started and the electroless plating process of the next wafer W of the wafer W is started, both chemicals are mixed. It can be said that the two chemicals are mixed immediately before the electroless plating process is performed. For this reason, it is avoided as much as possible that the electroless plating solution is held in an unstable state, and precipitation in the solution can be prevented. As a result, the electroless plating process can be performed on the surface of the wafer W while the electroless plating solution is stable, and the uniformity of film thickness and film quality between the wafers W is improved. Moreover, since there is no possibility of precipitation of particles, particle contamination and clogging of piping are not caused.

更に待機している無電解めっき液がほぼ全部ウエハＷに対する無電解めっき処理に使用されるため、無電解めっき液の消費量を抑えることができ、無電解めっき液のコストが可成り高いことから、処理コストを抑えることに寄与する。また第１の薬液供給路５及び第２の薬液供給路６において仮に合流点から離れたところにバルブが位置すると、薬液同士が十分に混ざらないが、本例のように合流点の近傍にバルブ５１、６１を設けることにより２液が十分に混合され、無電解めっき液の濃度が均一になり、結果として面内あるいは面間の均一性の高い処理を行うことができる。なお第１の薬液供給路５及び第２の薬液供給路６を縦方向にＶ字状に合流させる構造にすれば、液溜まりがなく、また気泡が入り込むおそれがない。 Furthermore, since almost all of the waiting electroless plating solution is used for the electroless plating process on the wafer W, the consumption of the electroless plating solution can be suppressed, and the cost of the electroless plating solution is considerably high. Contributes to reducing processing costs. Further, if the valve is located in the first chemical liquid supply path 5 and the second chemical liquid supply path 6 at a position away from the confluence, the chemical liquids are not sufficiently mixed together, but the valve is located near the confluence as in this example. By providing 51 and 61, two liquids are fully mixed and the density | concentration of an electroless-plating liquid becomes uniform, As a result, a process with high uniformity in a surface or between surfaces can be performed. If the first chemical liquid supply path 5 and the second chemical liquid supply path 6 are structured to merge in a V shape in the vertical direction, there is no liquid pool and there is no possibility of bubbles entering.

ここで前記薬液供給路５及び６に関しては、図７（ａ）に示すように第１の薬液供給路５に比べて第２の薬液供給路６を細くし、鉛直に起立した第１の薬液供給路５に対して第２の薬液供給路６を斜めに合流させた構造であってもよいし、あるいはまた図７（ｂ）に示すように両薬液供給路５、６をＶ字状に合流させ、その合流点に三方バルブ４０を設け、両薬液供給路５、６が同時に無電解めっき液供給路４１に連通する状態と、同時に遮断される状態との一方の状態を選択できるように三方バルブ４０を構成するようにしてもよい。 Here, with respect to the chemical liquid supply paths 5 and 6, as shown in FIG. 7A, the second chemical liquid supply path 6 is made narrower than the first chemical liquid supply path 5, and the first chemical liquid stands upright. The second chemical solution supply path 6 may be obliquely merged with the supply path 5, or the two chemical solution supply paths 5, 6 may be V-shaped as shown in FIG. 7B. The three-way valve 40 is provided at the junction point so that one of a state where both the chemical solution supply paths 5 and 6 are simultaneously connected to the electroless plating solution supply path 41 and a state where they are simultaneously shut off can be selected. The three-way valve 40 may be configured.

更に第１の薬液及び第２の薬液の流量を調整する手段としては、流量調整部を設けずに吐出量を制御できるポンプ例えばベローズポンプを用いて、各薬液の吐出量を調整して混合比を設定するようにしてもよい。 Further, as a means for adjusting the flow rates of the first chemical solution and the second chemical solution, a pump that can control the discharge amount without providing a flow rate adjusting unit, for example, a bellows pump, is used to adjust the discharge amount of each chemical solution to adjust the mixing ratio. May be set.

また図８及び図９は、本発明の他の実施の形態の要部を示す図である。この例においては、上部温調体３は、外形が円柱状でウエハＷよりも少し大きいサイズに作られており、その内部が温調用流体例えば純水などの熱媒が通流する通流室３１として構成されている。上部温調体３の上面における外縁部付近には熱媒供給管３２が接続され、また例えば上部温調体３の中心部について前記熱媒供給管３２と対称な位置には、熱媒排出管３３が接続されている。 8 and 9 are diagrams showing the main part of another embodiment of the present invention. In this example, the upper temperature adjusting body 3 has a cylindrical outer shape and is made slightly larger than the wafer W, and the inside of the upper temperature adjusting body 3 is a flow chamber through which a temperature control fluid such as pure water flows. It is comprised as 31. A heat medium supply pipe 32 is connected to the vicinity of the outer edge of the upper surface of the upper temperature control body 3, and the heat medium discharge pipe is located at a position symmetrical to the heat medium supply pipe 32, for example, at the center of the upper temperature control body 3. 33 is connected.

この通流室３１内には、管状の第１の薬液供給路５及び第２の薬液供給路６が上面側から配管され、各薬液供給路５、６は例えば螺旋状に形成され、途中で合流し、その合流管である無電解めっき液供給路４１の下端が吐出口４２として上部温調体３の下面に形成されている。この例においては、各薬液供給路５、６及び無電解めっき液供給路４１が上部温調体３の熱媒の通流室３１内に配置されている点を除けば上述の実施の形態と同様の考え方であり、第１の薬液供給路５及び第２の薬液供給路６における合流点の近傍にバルブ５１、６１が設けられると共に、無電解めっき液供給路４１における吐出口４２の近傍にバルブ４３が設けられている。またバルブ４３、５１、６１により挟まれる供給路４１の容積を、ウエハＷの１枚のめっき処理に必要な吐出量に対応させている。このような構成においては、無電解めっき液の温度変化が緩やかになり、無電解めっき液の温度を高い温度に設定する場合においても過加熱されない利点がある。 In the flow chamber 31, tubular first chemical liquid supply paths 5 and second chemical liquid supply paths 6 are piped from the upper surface side, and the respective chemical liquid supply paths 5 and 6 are formed in a spiral shape, for example. The lower end of the electroless plating solution supply path 41 which is a merged pipe is formed as a discharge port 42 on the lower surface of the upper temperature adjusting body 3. In this example, the chemical solution supply paths 5 and 6 and the electroless plating solution supply path 41 are the same as those in the above-described embodiment except that the chemical solution supply paths 5 and 6 and the electroless plating solution supply path 41 are arranged in the heat medium flow chamber 31 of the upper temperature adjusting body 3. In the same way, valves 51 and 61 are provided in the vicinity of the merge point in the first chemical solution supply path 5 and the second chemical solution supply path 6, and in the vicinity of the discharge port 42 in the electroless plating solution supply path 41. A valve 43 is provided. Further, the volume of the supply path 41 sandwiched between the valves 43, 51, 61 is made to correspond to the discharge amount necessary for the plating process for one wafer W. In such a configuration, the temperature change of the electroless plating solution becomes gradual, and there is an advantage that it is not overheated even when the temperature of the electroless plating solution is set to a high temperature.

更にまた第１の薬液供給路５及び第２の薬液供給路６において、次に薬液用開閉手段であるバルブ５１、６１を通って１枚の基板に使用される薬液が満たされている部位、即ち第１の薬液供給路５及び第２の薬液供給路６において夫々バルブ５１、６１からウエハＷの１枚を処理するのに必要な薬液が満たされている部位について、通流室３１内に位置させている。このようにすれば、薬液が既に無電解めっき液の処理温度まで加熱されているので、第１の薬液及び第２の薬液を混合した後、無電解めっきを開始するまでの時間を短くできる。 Furthermore, in the 1st chemical | medical solution supply path 5 and the 2nd chemical | medical solution supply path 6, the site | part where the chemical | medical solution used for one board | substrate is filled through the valves 51 and 61 which are the opening / closing means for chemical | medical solutions next, In other words, in the first chemical liquid supply path 5 and the second chemical liquid supply path 6, the portions filled with the chemical liquid necessary for processing one wafer W from the valves 51 and 61 are placed in the flow chamber 31. It is located. In this way, since the chemical solution has already been heated to the processing temperature of the electroless plating solution, the time until the electroless plating is started after mixing the first chemical solution and the second chemical solution can be shortened.

この点は無電解めっき処理の温度にも関係してくるが、例えば無電解めっき処理の温度が６０℃と高く設定した場合、１枚のウエハＷの表面に無電解めっき液を供給してから、次のウエハＷの表面に対して無電解めっき処理の準備ができるまでの時間が短いとすると、図１の実施の形態においては、無電解めっき液供給路４１にて無電解めっき液が処理温度まで昇温するために待ち時間を入れる必要が生じるかもしれない。これに対してこの例のように第１の薬液及び第２の薬液の温度を予め加熱しておけば（予熱しておけば）、両薬液を混合したときに処理温度まで昇温する時間が短くなり、結果としてスループットが高くすることができる。なお図１の実施の形態においても、第１の薬液及び第２の薬液の温度を予め加熱するための構造、例えば第１の薬液供給路５及び第２の薬液供給路６に夫々温調手段を設ける構造としてもよい。 This point also relates to the temperature of the electroless plating process. For example, when the temperature of the electroless plating process is set to be as high as 60 ° C., the electroless plating solution is supplied to the surface of one wafer W. Assuming that the time until the next surface of the wafer W is ready for the electroless plating process is short, the electroless plating solution is processed in the electroless plating solution supply path 41 in the embodiment of FIG. It may be necessary to wait for the temperature to rise. On the other hand, if the temperature of the 1st chemical | medical solution and the 2nd chemical | medical solution is heated beforehand like this example (if it preheats), time will be heated up to processing temperature when both chemical | medical solutions are mixed. As a result, the throughput can be increased. In the embodiment of FIG. 1 as well, a temperature control means is provided in the structure for preliminarily heating the temperature of the first chemical solution and the second chemical solution, for example, the first chemical solution supply path 5 and the second chemical solution supply path 6. It is good also as a structure which provides.

本発明は、第１の薬液及び第２の薬液が上述の例に限られるものではなく、混合されて時間が経つと液中析出あるいはその他の不具合を生じる薬液である場合に適用できる。 The present invention is not limited to the above-described example, and the first chemical solution and the second chemical solution can be applied to cases where the chemical solution causes precipitation in the liquid or other problems over time after mixing.

本発明に係る無電解めっき装置の実施の形態の全体構成を示す縦断側面図である。It is a vertical side view which shows the whole structure of embodiment of the electroless-plating apparatus which concerns on this invention. 上記の無電解めっき装置の要部を示す概略構成図である。It is a schematic block diagram which shows the principal part of said electroless-plating apparatus. 無電解めっき処理に用いられるウエハの表面構造を示す説明図である。It is explanatory drawing which shows the surface structure of the wafer used for an electroless-plating process. 上記の無電解めっき装置によりウエハに対して処理を行うときの様子を段階的に示す説明図である。It is explanatory drawing which shows a mode when processing with respect to a wafer by said electroless-plating apparatus in steps. 上記の無電解めっき装置によりウエハに対して処理を行うときの様子を段階的に示す説明図である。It is explanatory drawing which shows a mode when processing with respect to a wafer by said electroless-plating apparatus in steps. 上記の無電解めっき装置によりウエハに対して処理を行うときの様子を段階的に示す説明図である。It is explanatory drawing which shows a mode when processing with respect to a wafer by said electroless-plating apparatus in steps. 上記の実施の形態において、第１の薬液供給路及び第２の薬液供給路の合流点付近の構造の変形例を示す概略側面図である。In said embodiment, it is a schematic side view which shows the modification of the structure of the vicinity of the confluence | merging point of a 1st chemical | medical solution supply path and a 2nd chemical | medical solution supply path. 本発明の他の実施の形態に係る要部の概略を示す斜視図である。It is a perspective view which shows the outline of the principal part which concerns on other embodiment of this invention. 図８に示す上部温調体の内部を略解的に示す縦断側面図である。It is a vertical side view which shows roughly the inside of the upper temperature control body shown in FIG.

符号の説明Explanation of symbols

１１ウエハチャック
１２段部
１６傾斜機構
１７、１８ノズル
２１カップ体
３上部温調体
３０移動機構
３１通流室
４１無電解めっき液供給路
４２吐出口
４３バルブ
５第１の薬液用供給路
５１バルブ
６第２の薬液用供給路
６１バルブ
７１純水供給路
７３バルブ
３０２銅配線
３０４パラジウムからなる触媒層
３０５無電解めっき膜
DESCRIPTION OF SYMBOLS 11 Wafer chuck 12 Step part 16 Inclination mechanism 17, 18 Nozzle 21 Cup body 3 Upper temperature control body 30 Movement mechanism 31 Flow chamber 41 Electroless plating solution supply path 42 Discharge port 43 Valve 5 1st chemical | medical solution supply path 51 Valve 6 Second chemical liquid supply path 61 Valve 71 Pure water supply path 73 Valve 302 Copper wiring 304 Catalyst layer 305 made of palladium Electroless plating film

Claims

基板を横向きの姿勢で保持する基板保持部と、
互いに混合されて無電解めっき液を形成する第１の薬液及び第２の薬液が夫々通流する第１の薬液供給路及び第２の薬液供給路と、
これら第１の薬液供給路及び第２の薬液供給路がその上流端にて合流し、その下流端に吐出口が形成された無電解めっき液の供給路と、
この無電解めっき液の供給路内の無電解めっき液の温度を調整する供給路温調手段と、
前記第１の薬液供給路及び第２の薬液供給路の各々における合流点の近傍に設けられた薬液用開閉手段と、
前記無電解めっき液の供給路における前記吐出口の近傍に設けられためっき液用開閉手段と、
前記基板に対して無電解めっきが行われている間に無電解めっき液の供給路内を満たしていた無電解めっき液を次の基板の表面に供給するために前記薬液用開閉手段及びめっき液用開閉手段を制御する制御手段と、を備え、
前記薬液用開閉手段とめっき液用開閉手段との間の供給路内の容積は、１枚の基板を無電解めっき処理するために必要な吐出量に相当することを特徴とする無電解めっき装置。 A substrate holder for holding the substrate in a horizontal orientation;
A first chemical solution supply path and a second chemical solution supply path through which a first chemical solution and a second chemical solution, which are mixed with each other to form an electroless plating solution, respectively flow;
An electroless plating solution supply path in which the first chemical solution supply path and the second chemical liquid supply path merge at the upstream end thereof, and a discharge port is formed at the downstream end thereof;
Supply path temperature adjusting means for adjusting the temperature of the electroless plating solution in the supply path of the electroless plating solution;
Chemical liquid opening / closing means provided in the vicinity of the junction in each of the first chemical liquid supply path and the second chemical liquid supply path;
Plating solution opening / closing means provided in the vicinity of the discharge port in the electroless plating solution supply path;
In order to supply the electroless plating solution that has filled the inside of the supply path of the electroless plating solution to the surface of the next substrate while the electroless plating is being performed on the substrate, the opening / closing means for chemical solution and the plating solution Control means for controlling the open / close means for use,
An electroless plating apparatus characterized in that the volume in the supply path between the chemical solution opening / closing means and the plating solution opening / closing means corresponds to a discharge amount required for electroless plating of one substrate. .

第１の薬液はめっき金属の金属塩を含む液であり、第２の薬液は電子の供給源である還元剤を含む液であることを特徴とする請求項１に記載の無電解めっき装置。 The electroless plating apparatus according to claim 1, wherein the first chemical solution is a solution containing a metal salt of a plating metal, and the second chemical solution is a solution containing a reducing agent that is an electron supply source.

第１の薬液及び第２の薬液の夫々の流量を調整するための手段を備えていることを特徴とする請求項１または２に記載の無電解めっき装置。 The electroless plating apparatus according to claim 1 or 2, further comprising means for adjusting the flow rates of the first chemical liquid and the second chemical liquid.

基板保持部に保持された基板の表面に対向すると共に、基板の有効領域よりも大きく形成され、下面に前記吐出口が形成された上部温調体と、この上部温調体を基板の表面との間に無電解めっき液を満たすための処理位置と、この処理位置から離れた待機位置との間で相対的に移動させる移動機構とを備えたことを特徴とする請求項１ないし３のいずれか一に記載の無電解めっき装置。 An upper temperature adjustment body facing the surface of the substrate held by the substrate holding portion and larger than the effective area of the substrate and having the discharge port formed on the lower surface, and the upper temperature adjustment body as the surface of the substrate 4. A moving mechanism for relatively moving between a processing position for filling the electroless plating solution between the processing position and a standby position away from the processing position. An electroless plating apparatus according to claim 1.

第１の薬液供給路及び第２の薬液供給路において、次に薬液用開閉手段を通って１枚の基板に使用される薬液が満たされている部位を温度調整する手段を設けたことを特徴とする請求項１ないし４のいずれか一に記載の無電解めっき装置。 In the first chemical liquid supply path and the second chemical liquid supply path, there is provided means for adjusting the temperature of the portion filled with the chemical liquid used for one substrate through the chemical liquid opening / closing means. The electroless plating apparatus according to any one of claims 1 to 4.

前記上部温調体はその内部が温調用流体の通流室として構成され、無電解めっき液とこの温調用流体との間で熱交換するために前記無電解めっき液の供給路の全部がこの通流室内に配置されることにより前記供給路温調手段を兼用することを特徴とする請求項１ないし４のいずれか一に記載の無電解めっき装置。 The inside of the upper temperature adjusting body is configured as a flow chamber for the temperature adjusting fluid, and all of the supply path for the electroless plating solution is used for heat exchange between the electroless plating solution and the temperature adjusting fluid. The electroless plating apparatus according to any one of claims 1 to 4, wherein the electroless plating apparatus is also used as the supply path temperature adjusting means by being disposed in a flow passage chamber.

第１の薬液供給路及び第２の薬液供給路において、次に薬液用開閉手段を通って１枚の基板に使用される薬液が満たされている部位が上部温調体の通流室内に位置していることを特徴とする請求項６記載の無電解めっき装置。
In the first chemical liquid supply path and the second chemical liquid supply path, the portion filled with the chemical liquid used for one substrate through the chemical liquid opening / closing means is located in the flow chamber of the upper temperature regulator. The electroless plating apparatus according to claim 6, wherein: