Summary of the invention
A kind of equipment for by metal or metal alloy electro-deposition on the semiconductor wafer is provided.The equipment includes platingSlot, the electroplating bath have the anode being arranged in it.Cathode including semiconductor wafer is arranged to the surface face to be platedIt is spaced apart to anode and with anode.Power supply provides the electrical contact between anode and cathode.Electrical contact with chip passes through conducting ring(conducting ring is formed to provide and continuously contact with the edge of chip) or the conducting ring by being electrically insulated are implemented, the electricityThe conducting ring of insulation has on-insulated conductive fingers, which extends internally to contact the edge of chip, which existsDiametrically it is slightly smaller than conducting ring.
The equipment includes solution injection apparatus, which is used to convey electroplating solution partly leads to what is be platedThe surface of body chip.The solution injection apparatus is arranged between the anode and cathode.The solution injection apparatus includes at least oneHollow cross bar, but it may include 2,3,4,5 or more hollow cross bars.Cross bar or multiple cross bars are formed with arrangement and embark on journeyA series of holes spaced apart, which extends about from an end of cross bar or an endTo near the other end or the other end of cross bar.The solution injection apparatus also includes hollow support rod, the hollow supportBar is attached to the centre of the hollow cross bar at one of its end to form " T-bar ", and wherein the support rod is the perpendicular of T-barStraight part and the hollow cross bar be disposed at the top of the support rod or on top so that in the cross bar rows of oneIt is directed toward the cathode in series hole spaced apart.Alternatively, cross bar can be attached to support at one of its end in an identical mannerBar is formed " L shape bar ", and cathode is directed toward in a series of rows of holes spaced apart in cross bar.If there is more than two crossBar, then support rod is attached so that inside of the cross bar from the support rod being centrally arranged towards electroplating bath is with right angle radiation and extends.
In this embodiment, which includes the device for pushing solution conveying assembly around its axis.Preferred realIt applies in example, the device for pushing includes at least contralateral exposure in hollow cross bar, and one of side opening pair is formed and arrangesNear the end of the side of cross bar and another of side opening pair is formed and is arranged near the end of the opposite side of cross bar.In alternative embodiments, the device for pushing solution conveying assembly around its axis includes isolated motor, the motor of the separationSupport rod is functionally connect and rotated about the axis thereof with support rod, therefore cross bar is caused to rotate, and is wanted with electroplating solution injectionThe surface for the semiconductive wafer being plated.
The equipment also may include that electroplating solution keeps case, which keeps case to be used to keep electroplating solution and makeElectroplating solution is recycled into and leaves electroplating bath, and solution injection apparatus also may include pump, which is used to electroplating solutionCase is kept to be pumped into solution injection apparatus from electroplating solution.
In a preferred embodiment, which rotates around central axis, to be used in a manner of repeating and is continuousThe surface of electroplating solution injection this to be plated semiconductive wafer.In alternative embodiments, this to be plated semiconductive is brilliantPiece is rotated around central axis so that the electroplating solution is injected in this in a manner of repeating and is continuous by static solution injection apparatusOn chip.Electrical contact with chip with the conducting ring or conductive fingers of afer rotates by being implemented.In another embodimentIn, chip and solution injection apparatus can be rotated around central axis.
Specific embodiment
The present invention is to be used to form uniform multiple layer metal or metal alloy in semiconductor wafer substrate by electro-depositionDevice and method.Uniform layer as defined here have less than 10% and preferably less than 5% thickness change coefficientCV。
In one embodiment of the invention, the electroplating bath 6 being formed of an electrically insulating material is provided.Electroplating bath is cylindrical shapeShape, the bottom that there is the top opened and have central opening 9.Anode 4 is disposed in the bottom of electroplating bath.Anode is circularAnd the diameter with the interior diameter for being slightly smaller than electroplating bath.The anode can be to be made of platinum plating niobium, platinized titanium or yttrium oxideDimensionally stable insoluble electrode or it can be soluble electrode, such as copper.It is suitable for the plating selection of semiconductive waferWhen anode is in the limit of power of those skilled in the art.Anode 4 is formed with hole in its center.As shown in fig. 1, it is by leadingLine 18, the anode conducting ring 40 of insulation and titanium screw 42 are electrically connected to the plus end of power supply 14.
In embodiment shown here, electroplating bath is vertically arranged.As it will appreciated by a person of ordinary skill, platingSlot can also be arranged horizontally or even be inverted, but this will complicate loading and the unloading of electroplating bath.
Electroplating bath should have the diameter for the diameter for being slightly smaller than semiconductive wafer.Flange 8 is installed to the top of electroplating bath.It provides peripheral ledge, and chip is disposed on the peripheral ledge.Cathode conducting ring 10 is electrically connected to the negative terminal of power supply.One systemColumn power spring finger 7 is installed to cathode conducting ring 10 by screw 9, and is in electrical contact the edge removal region of chip 2.SoAnd any amount of conductive fingers 7 can be used, 4-8 finger is typical.Alternatively, continuously contacting with ring can useRegion is removed in the edge of contact chip.Advantageously, conducting ring 10 is electrical isolation other than it is contacted in place of conductive fingers's.
It is as shown herein, cathode 2 (that is, the semiconductive wafer to be plated) be arranged to face that it to be plated towardsAnode.In one embodiment, cathode can be maintained in resting position by cathode anchor 8, which is arrangedOn the edge of electroplating bath 6.Cathode anchor also may be mounted on the side close to the electroplating bath at top or in any other positionIn setting, as long as cathode can be maintained in its resting position appropriate at the top of electroplating bath by it.Cathode anchor is in Fig. 3It is shown in detail.It includes bracket itself 8, which itself is made from a material that be electrically non-conductive, and is made of polymer to most typically.BranchFrame 8 is fixed to the top edge of plating groove sidewall and accommodates cathode conducting ring 10, which is manufactured by metal, typicalGround is made of stainless steel, and power spring finger 7 by screw 9 be attached to the cathode conducting ring (can be most in such as Fig. 4 AIt sees goodly).Rubber sheet gasket 11 seals off the interior section of electroplating bath and cathode conducting ring 10, and prevents solution from connecingTouch cathode conducting ring.Chip 2 is held in place by disk 34, the disk by keep clip 36 in a detachable fashion byFixed to bracket 8, which is rotated to keep or discharge disk 34 to allow the loading of the chip relative to electroplating bathAnd unloading.
Power supply can be DC power supply or the pulse power or recurrent pulses inverter.It is connected to by conducting wire 18Anode and cathode is connected to by conducting wire 12.
The equipment further includes solution injection apparatus, which includes solution conveying group in one embodimentPart, the solution conveying assembly form (as shown in fig. 1) by hollow tubular supporting bar 20 and hollow tubulose cross bar 22.TubuloseCross bar is installed to one of the end of support rod and perpendicular therebetween.In this embodiment, the component therefore shapeAt T-shaped structure.The other end (end for being not attached to cross bar) of support rod forms the hole for being used to be cooperated in anode and platingIn the hole in opening in the bottom of slot and extend through the hole in the opening in the hole in anode and the bottom of electroplating bath simultaneouslyAnd enter electroplating bath manifold 26, which is medially installed to the outer bottom of electroplating bath.It is cooperated to bearing assembly 25In, which enables it to rotate around its vertical axis.Bearing assembly 25 includes two ball races, the ball bearing housingCircle is arranged in around support rod and in manifold (as shown in fig. 1).
Support rod is hollow and is referred to as and is shown as tubulose, but it needs not be circular cross section.It is anyHollow shape will work, and maintain cross bar in its appropriate location for the horizontal relationship opened at interval with cathode as long as it is executedFunction.
Cross bar 22 is hollow and is formed with a series of solution spray-holes 24 spaced apart, the solution spray-hole or it is more orFew the other end that cross bar is extended to from an end of cross bar.Solution spray-hole along the cross bar towards chip side and withStraight row is positioned (as shown in Figure 5).Cross bar is also formed with closing end.It is at least one near each of closing endTo cross bar side opening 28.Every a pair of cross bar side opening, which is disposed on cross bar, makes this straddle apical pore to cross bar side opening, that is, a pair of of cross barA cross bar side opening in side opening is located on the side of cross bar and this is located at cross bar to another cross bar side opening in cross bar side openingThe other side on.See Fig. 5.
Such as support rod, cross bar 22 needs not be (that is, circle) of circular cross section.It can be it is rectangle, square,Triangle the, oval (function on the surface for the semiconductor wafer that its execution injection will be still allowed for be plated with electroplating solutionAny shape of energy).The height of solution conveying assembly makes cross bar be positioned to be closely spaced with cathode.Between cross bar and cathodeDistance should be in about 5 to 50mm range.As shown, cross bar is centrally mounted on support rod, therefore works as the groupWhen part rotates, chip is contacted with the fluid of the two half-unit from cross bar.
Solution conveying assembly shown here is exemplary.Unwanted to be, support rod is mounted to the centre of cross barTo form T-shaped structure (as shown in Figure 5 A).It may be mounted at end to form L-shaped structure (as shown in Figure 5 C).SubstitutionGround, the component may include support rod and three cross bars, which is installed to support rod (such as Fig. 5 B in their one of endShown in) or the component may include support rod and right angle or " X " construction four cross bars (as shown in fig. 5d).
As shown in Figure 2, electroplating bath 6 is removably mounting in electroplating solution holding case 1.Ladder on manifold 26Shape screw thread 27 penetrates receiving port 17, which is fixed to the bottom that solution keeps case 1.Electroplating bath manifold 26 will be electroplatedSlot is fixed on the flowing for keeping in case and also serving as conduit so as to electroplating solution.Manifold 26 is connected to the outlet 33 of pump 32.Pump32 entrance 31 is connected to electroplating solution and keeps case.Electroplating solution keeps case 1 to be pumped into this by entrance 31 from electroplating solutionPump.It leaves the pump by outlet 33 and enters electroplating bath by manifold 26.Near top, which is opened, at it is formed in electroplating bath 6Wall in solution leave hole 30 electroplating solution allowed to leave electroplating bath and rework solution and keep case 1.Therefore, when in operationWhen, electroplating solution continuously flows through the component.
Electroplating solution keeps case to be assigned to electroplating bath by manifold 26 and solution conveying assembly 16 from electroplating solution.SolutionThe support rod 20 for entering solution conveying assembly 16 from conduit, flow upwardly into cross bar 22 and flow out a series of solution spaced apart fromIt aperture 24 and flows on cathode.Solution leaves hole 30 and needs to be oriented as close to wafer surface to prevent gas to be capturedObtain on a surface of a wafer or at least minimize the amount for the gas being captured.Fluid also flows out the end hole 28 in the end of cross bar 22And this forces solution conveying assembly 16 to rotate around its vertical axis.This leads to continuously rotating for during plating electroplating solutionJet impact cathode surface.
In operation, electroplating solution keeps support of the electroplating solution in case 1 by manifold 26 and solution conveying assembly 16Bar is pumped into electroplating bath 6 by pump 32.Solution flows upwardly into cross bar 22 from the bottom of support rod and passes through 24 He of solution spray-holeEnd hole 28 flows out solution conveying assembly and enters electroplating bath.When electroplating bath 6 be filled with fluid when, fluid by electroplating bath solution fromAperture 30, which flows out electroplating bath and flow back into electroplating solution, to keep in case 1.It flows through cross bar and flows out the fluid of cross bar side opening 28Power causes solution conveying assembly to rotate around its vertical axis, and when fluid leaves a series of holes in cross bar, this provides contact quiltThe injection of the electroplating solution of the static semiconductor wafer of plating continuously rotated.Alternatively, solution conveying assembly can be with shapeAs no cross bar side opening and external mechanical devices can be used for rotation solutions conveying assembly.
Optionally, as shown in Figure 4 A, which includes auxiliary shield 37 and/or rotating shroud 36.The purpose of the shieldIt is to improve plating performance in terms of minimizing thickness CV.Auxiliary shield 37 is made of circular disc ring, which can be in crossIt is mounted in electroplating bath above or below bar.By the different width of test and selection leads to the width of minimum change coefficient,The width of shield can be determined with sample plot.Our experiment is it has been shown that the width of auxiliary shield should be about 1 to about2cm.Triangle shield 36 is flat cheese slice or triangular structure, it is attached to cross bar 22 in the end of its most acute angle.?In the embodiment that wherein chip is static and solution injection apparatus rotates, triangle shield is rotated with cross bar 22.
In alternative embodiments, semiconductive wafer is maintained in the fixation device of rotation and solution injection apparatus is quietOnly.Electrical contact with chip with the conducting ring or finger of afer rotates by being implemented.In this embodiment, solutionInjection apparatus, which can be arranged, to be spaced apart with the chip of rotation and is supplied with fluid from pump discharge, which can be byIt is arranged in outside the case.
In another alternate embodiment, electroplating chamber can be located at outside plating solution reservoir.In this embodiment, it is openingThe solution that mouth 30 leaves electroplating chamber are collected by slot, which is fixed to outside and the upper periphery of electroplating chamber.It is collected by this slotSolution is connected to plating solution reservoir by pipeline and flows to the reservoir from the slot by gravity.Solution from the reservoir canThe entrance of electroplating chamber is supplied to pipeline by pumping.The present invention may be implemented such that electroplating chamber is located at the interior of solution reservoirs casePortion or outside.