JP2007270313A - Electroplating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroplating apparatus in which a good quality uniform metallic film is simply formed on a semiconductor wafer with high productivity. <P>SOLUTION: The electroplating apparatus 1 in which electroplating is applied to the wafers 14a-14c by circulating a plating solution in one plating bath and applying power between wafers 14a-14c of the cathodes and electrodes of anodes 13a-13c is provided with a paddle 18 for stirring the plating solution in the vicinity of the surfaces of the wafers 14a-14c to cause turbulent flow and a stirrer 19 for stirring the whole of the plating solution in the plating bath. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electroplating apparatus for forming a metal film on the surface of a semiconductor wafer or the like.

  Conventionally, in the bump formation process and wiring formation process of semiconductor element manufacturing, a metal film such as gold or copper is formed over a thickness of several μm on a semiconductor wafer, and this metal film is formed by electroplating. It is done. Since this metal film plays a role of introducing a current into the semiconductor element, it needs to have good conductive properties. Therefore, in electroplating, it is required to form a metal film having a high purity film quality and a uniform film thickness.

  In electroplating, a semiconductor wafer is used as a cathode, immersed in a plating solution together with an anode, a voltage is applied between the electrodes, and metal ions in the plating solution are deposited on the semiconductor wafer to form a metal film. At this time, since metal ions receive electrons from the surface of the semiconductor wafer, a current flows between the electrodes. Therefore, the deposition amount of the metal film is roughly determined by the time integration of the current flowing during plating. However, in order to form a metal film having a desired film quality and film thickness uniformly within a semiconductor wafer surface and stably between semiconductor wafers, not only the plating time and the amount of input current are determined, but also the surface of the semiconductor wafer. It is necessary to strictly control the temperature field, flow field, concentration field, electric field, and purity of the plating solution.

  In order to satisfy such requirements, various devices have been devised in the electroplating apparatus, and as a means for controlling the temperature field, flow field, and concentration field, the plating solution is jetted as a jet and agitated against the surface to be plated ( Patent Document 1), those in which the flow is a steady laminar flow on the surface of the semiconductor wafer (see Patent Document 2), and those in which the flow near the surface of the semiconductor wafer is intermittently turbulent (see Patent Document 3) are disclosed. Has been.

  Moreover, as a device for controlling the electric field, a device in which a shielding plate is provided between the anode and the wafer (see Patent Documents 4 and 5) and a device in which the vicinity of the wafer surface is scanned with a rod-shaped anode (see Patent Document 6) are disclosed. Has been.

  Furthermore, as a means for controlling the purity, a plating solution circulation pump, an impurity removal filter, and a temperature control mechanism are provided outside the plating bath so that the plating solution is always circulated during plating (Patent Documents 1 to 3). 6). Such a circulation system is used because during the plating, hydroxide is generated in the plating solution as a reaction accompanying the deposition of metal on the wafer surface, and fine dust and dirt from the outside of the plating solution. Floating substances are generated by taking in, etc., and these floating substances are easy to take in metal ions in the plating solution and are attracted and deposited on the wafer by Coulomb force, increasing the specific resistance as impurities in the metal film. This is because it becomes a factor.

Japanese Patent Publication No. 60-58799 JP-A-7-54189 JP-A-9-273000 Japanese Patent Publication No. 61-48590 JP 2003-34893 A Japanese Patent No. 2935647 Japanese Patent Laid-Open No. 6-20098 Japanese Patent No. 2598877

  However, if the above-mentioned circulation system is provided, the entire electroplating apparatus becomes complicated, resulting in an increase in cost and deterioration in maintainability, as well as variations in the flow rate of the plating solution circulation pump and the control temperature of the temperature control mechanism. As a result, there is a problem that a uniform metal film cannot be formed.

  In addition, when using a sulfite-based plating solution, sulfite ions in the plating solution are easily oxidized by oxygen in the air, and this oxide may also be incorporated as impurities into the metal film. It is necessary to avoid as much as possible. Here, the electroplating apparatus provided with the circulation system has a problem that the life of the plating solution is shortened because the chance of contact with air increases when the plating solution overflows outside the bath. On the other hand, what prevents the oxidation of the plating solution by using a plating bath and a circulation system as an inert gas atmosphere is disclosed (see Patent Document 7), but the use of this inert gas atmosphere further increases the cost of the apparatus. There is a problem of generating.

  On the other hand, in an actual semiconductor element manufacturing process, high productivity is required in addition to obtaining a uniform and high-quality metal film by the above-described management of the plating solution. In other words, the time for plating on one wafer is generally determined by the optimum current density for plating and the required film thickness. Therefore, in order to improve the productivity of metal film formation by electroplating, a plurality of wafers are required. It is important that the two can be plated simultaneously.

  However, if a plurality of wafers and anodes are immersed in one plating bath and plating is performed simultaneously, stray current using a plating solution as a medium is generated between the electrodes, and an unstable electric field is formed as a result. There was a problem that a high-quality and uniform metal film could not be formed.

  Therefore, as shown in FIG. 18, a method of immersing the wafer in an independent plating solution system and supplying power can be considered. However, in this method, it is necessary to manage the ion concentration and the like for each plating solution system. The film quality and film thickness vary between wafers. In addition, in this method, a plurality of apparatuses for a single wafer itself are prepared, and plating apparatuses corresponding to the number of wafers to be simultaneously processed must be prepared. For this reason, it is common to provide a common storage tank for a plurality of independent plating baths and circulation systems and supply the same plating solution (see Patent Document 8).

  However, since a common plating solution is used, the stray current mediated by the plating solution cannot be avoided as described above. Furthermore, since the circulatory system is independent, a pump and a temperature control mechanism may become a factor which varies with each circulatory system. Compared to the apparatus for preparing a plurality of electroplating apparatuses per se shown in FIG. 18, only a liquid storage tank is used, and plating baths and circulation systems must be prepared for the number of wafers to be simultaneously processed. It remains the same, and the device configuration is complicated and large.

  On the other hand, as shown in FIGS. 19 and 20, it is conceivable to perform plating on a plurality of wafers in one plating bath. In any case, stray currents between wafers can be effectively reduced. There is a problem in that the amount of precipitation cannot be suppressed and the amount of precipitation varies between wafers.

  The present invention has been made in view of the above, and an object thereof is to provide an electroplating apparatus capable of forming a high-quality and uniform metal film on a semiconductor wafer easily and with high productivity.

  In order to solve the above-described problems and achieve the object, an electroplating apparatus according to the present invention circulates a plating solution in one plating bath to provide a gap between an object to be plated which is a cathode and an electrode which is an anode. An electroplating apparatus for applying electroplating to the object to be plated by energization, wherein the plating solution in the vicinity of the surface of the object to be plated is stirred locally to turbulently flow, and the plating solution in the plating bath And a whole stirring means for stirring the whole.

  Further, in the electroplating apparatus according to the present invention, in the above invention, the overall stirring means slows the flow rate at the bottom of the plating bath as compared to the flow rate in the vicinity of the object to be plated, and at the bottom of the plating bath. It is characterized by forming a stagnation region in which suspended matter in the plating bath is precipitated.

  An electroplating apparatus according to the present invention is an electroplating apparatus for simultaneously plating a plurality of objects to be plated in a state where a plurality of objects to be plated are arranged in the same plating bath. A plurality of variable power supplies that are connected in common and supply current to each object to be plated, and control means for controlling the current value supplied from each variable power supply to equalize the potentials of the electrodes that are anodes; It is provided with.

  The electroplating apparatus according to the present invention is the above-described invention, wherein in the above invention, the local agitating means for agitating the plating solution in the vicinity of the surface of the object to be plated and turbulently agitates the entire plating solution in the plating bath. And a whole stirring means.

  Further, in the electroplating apparatus according to the present invention, in the above invention, the overall stirring means slows the flow rate at the bottom of the plating bath as compared to the flow rate in the vicinity of the object to be plated, and at the bottom of the plating bath. It is characterized by forming a stagnation region in which suspended matter in the plating bath is precipitated.

  The electroplating apparatus according to the present invention is characterized in that, in the above invention, the electrode as the anode and the semiconductor wafer as the object to be plated are arranged substantially in parallel.

  Moreover, the electroplating apparatus according to the present invention is characterized in that, in the above-mentioned invention, the semiconductor wafer as the object to be plated is installed substantially horizontally upward or substantially horizontally downward.

  The electroplating apparatus according to the present invention is characterized in that, in the above-described invention, the semiconductor wafer as the object to be plated is arranged on the same horizontal plane.

  The electroplating apparatus according to the present invention is characterized in that, in the above invention, a dielectric member corresponding to the shape of the object to be plated is installed between the object to be plated and the anode.

  The electroplating apparatus according to the present invention is characterized in that, in the above-mentioned invention, the surface of the plating solution is covered with an inert gas atmosphere.

  In the electroplating apparatus according to the present invention, the local stirring means stirs the plating solution in the vicinity of the surface of the object to be turbulent, and the whole stirring means stirs the entire plating solution in the plating bath. Therefore, the temperature field, flow field, concentration field, electric field, and purity of the plating solution can be effectively and uniformly managed, and even when a plurality of platings are performed simultaneously in one plating bath, The film quality and film thickness do not vary between plated objects and batches, and a stable metal film can be formed. With a simple structure, a high-quality and uniform metal film can be formed with high productivity. Play.

  The electroplating apparatus according to the present invention is commonly connected to an electrode serving as an anode when a plurality of objects to be plated are plated simultaneously in a state where a plurality of objects are disposed in the same plating bath, and serves as a cathode. A plurality of variable power supplies for supplying current for each object to be plated, and a control means for controlling the current value supplied from each variable power supply to equalize the potential of the electrode serving as the anode, Since the current value for each workpiece can be controlled with the electrode potentials of the electrodes being equalized, stray currents can be eliminated, so that the film quality and film thickness between the workpieces and between batches can be reduced. There is an effect that a stable metal film can be formed without variation.

  Hereinafter, an electroplating apparatus which is the best mode for carrying out the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a schematic configuration of an electroplating apparatus according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing a schematic configuration of the electroplating apparatus shown in FIG. Further, FIG. 3 is a schematic diagram showing the flow of the plating solution in the vicinity of the wafer as the object to be plated in the electroplating apparatus shown in FIG. 1 to 3, the electroplating apparatus 1 does not have a plating solution circulation system outside and performs electroplating on one or more wafers in one plating bath.

  The electroplating apparatus 1 forms a plating bath filled with a sulfite-based (non-cyanide) plating solution 11 in a plating container 10 and arranges three wafers 14a to 14c as objects to be plated as cathodes in the plating bath. And three fixing jigs 12a to 12c for supporting the three anodes 13a to 13c in the plating bath. Each of the wafers 14a to 14c is disposed on the fixing jigs 12a to 12c with the plating surface facing substantially horizontally upward, and each of the anodes 13a to 13c is provided substantially parallel to each of the wafers 14a to 14c.

  At the bottom of the plating bath, a stirrer 19 is provided for constantly stirring the entire plating solution. The stirrer 19 is rotated by a rotating magnetic field generated by a stirrer rotating unit 20 provided at the bottom of the plating container 10, and the entire plating solution in the plating bath is stirred by this rotation. Further, a paddle 18 is attached to the shaft tip of the motor 17 provided at the upper center of the wafer container 10. The paddle 18 is disposed so as to rotate between the wafers 14a to 14c and the anodes 13a to 13c, and in particular, intermittently agitate the vicinity of the wafer surface.

  The respective variable power sources 15a to 15c are connected to the respective wafers 14a to 14c, and ammeters 16a to 16c are connected in series to the variable power sources 15a to 15c, respectively, so that the amount of current flowing through the respective wafers 14a to 14c. Is controlled. Further, since the anodes 13a to 13c are commonly connected to the positive side of the variable power sources 15a to 15c, the electrode potentials of the anodes 13a to 13c are equal.

  A heater 21 is further provided at the bottom of the plating container 10, and a thermocouple 22 as a temperature detecting means in the plating bath is provided in the plating bath. The heater 21 and the thermocouple 22 are used to adjust the temperature of the plating bath. Used for.

  The controller C controls local stirring in the vicinity of the wafer by the paddle 18 by controlling the number of rotations of the motor 17. Moreover, the controller C controls the rotation by the stirring bar 19 by controlling the stirring bar rotating unit 20, and thereby controls the stirring of the entire plating solution in the plating bath. Further, the controller C controls the energization amount of the heater 21 based on the temperature information input from the thermocouple 22 to control the temperature of the plating bath. Further, the controller C controls the variable power sources 15a to 15c based on the current values input from the ammeters 16a to 16c, and thereby the amount of current flowing through the wafers 14a to 14c, that is, the deposition amount of plating. To control.

  As shown in FIG. 3, when the paddle 18 moves intermittently between the wafer 14b and the anode 13b, a turbulent region E1 is generated between the wafer 14b and the anode 13b, and the flow of the plating solution Is turbulent.

  By the way, in a general electroplating apparatus, the plating solution is stirred only by the stirrer 19, but in this case, the plating surface forms a highly uneven film. For example, in the bump and wiring formation process in the semiconductor manufacturing process, the wafer is electroplated. In this case, the wafer surface is formed with a barrier metal on the entire surface by sputtering, and the outermost surface is patterned with a resist or the like. The metal film formed by plating is selectively formed only on the barrier metal having no resist. For this reason, at the time of electroplating, there are irregularities with a height of several μm due to the resist near the surface of the wafer, and the flow field of the plating solution is completely different from the uniform flow direction in a certain direction by the whole stirring, Entrainment vortex flow and stagnation are formed between the resists on which the metal film is formed. On the metal surface, the plating reaction proceeds as needed and the metal ions are consumed. Therefore, a steady and non-uniform flow field such as entrainment vortex and stagnation forms a non-uniform concentration distribution. As shown in FIG. 5, non-uniform film formation occurs between resists or upstream and downstream, resulting in increased surface irregularities. When the metal film having the surface shape formed as described above is used for a wiring or the like, a spark or the like is generated due to charge concentration on the convex portion, which has a fatal effect on the device performance.

  On the other hand, in the first embodiment, the paddle 18 stirs the vicinity of the surface of the wafer 14b to positively generate turbulent flow so as to eliminate non-uniform flow fields and concentration fields. In particular, a metal ion deficient layer generated near the wafer surface where metal ions are consumed on the wafer surface can be eliminated, and the flow field and concentration field near the wafer surface can be made uniform. For this reason, for example, as shown in FIG. 4, the rise of the metal film on the downstream side of the resist is smaller than in FIG. 5, and a metal film having a flat surface shape is formed. Although the paddle 18 has been described as being intermittently stirred, it may be constantly performed.

  In the first embodiment, the entire plating solution is stirred by the stirrer 19 described above to uniformly form the temperature field, the flow field, and the concentration field in the plating bath. The child 19 forms a stagnation region E2 having a low flow velocity at the bottom of the plating bath.

  Usually, the bottom of the plating bath is not affected by the stirring by the paddle 18, and a flow field of the plating solution is formed only by the stirring bar 19 and natural convection. Here, the stirrer 19 forcibly generates a slow flow field in which the suspended matter in the plating bath precipitates at the bottom of the plating bath where the influence of the stirring by the paddle 18 does not reach. The flow field at the bottom of the plating bath has a flow rate that is at least slower than the flow field near the wafer. Here, the plating solution in the vicinity of the wafer and the bottom of the plating bath circulates between the upper portion of the wafer and the bottom of the plating bath through the right and left of the fixing jigs 12a to 12c. Objects gradually accumulate on the bottom of the plating bath. This is because suspended matters in the plating solution perform Brownian motion as particles and float and sink while colliding with each other. Therefore, if the kinetic energy of the plating solution is small, the particles gradually precipitate as large particles. Thereby, a clean plating solution is always supplied near the wafer surface. However, after plating is completed, the plating solution is transferred to a sealed tank outside the bath and stored. At that time, suspended matters in the plating solution are removed by filtering, and the plating bath is washed with pure or the like.

  In the first embodiment, a plurality of wafers to be plated are simultaneously electroplated. In this case, the electric circuit system has common cathodes 13a to 13c as shown in FIG. The power supply potentials of the cathodes are made equal to each other, and the variable power supplies 15a to 15c are provided for the wafers 14a to 14c, which are cathodes, to control the current values.

  In this case, no stray current is generated between the anodes 13a to 13c, and the electrode potentials are equalized by controlling the currents flowing through the wafers 14a to 14c to be the same. The amount of precipitation becomes equal. Actually, a stray current flows from the anodes 13a to 13c to other than the paired wafers 14a to 14c, but the electrode potentials of the anodes 13a to 13c, the electrode potentials of the wafers 14a to 14c, and between the electrodes Since the potential difference is equal, the stray current flows uniformly from all the anodes 13a to 13c and flows equally to all the wafers 14a to 14c. As a result, the stray currents cancel each other out and can be substantially ignored. Therefore, it is not necessary to provide plating baths and circulation systems for the number of wafers to be processed simultaneously, and the temperature field, flow field, and concentration field on the surfaces of the wafers 14a to 14c can be made uniform without special control. Can do.

  In the configuration shown in FIG. 6, the stray current is theoretically canceled out, and there should be no difference in the deposition amount between the wafers 14 a to 14 c. However, in reality, if the resistance value in the wiring or connection portion from the branch portion of the wiring to the anodes 13a to 13c is different, the electrode potential of each anode 13a to 13c is different due to potential loss in that portion. Will cause a stray current. In general, in an electroplating apparatus, an electrode is often supplied with an alligator clip or the like, but such a method has low contact reliability and not only high contact resistance but also reproducibility. In addition, if the connecting portion is in a portion exposed to water vapor evaporated from the plating solution, an electrolytic corrosion reaction is likely to occur, and contact reliability is further reduced. Here, the potential difference between the anodes 13a to 13c can be eliminated by controlling the potential loss from the branch portion of the wiring to the anodes 13a to 13c. For example, in the circuit configuration shown in FIG. 19, it is difficult in principle to make the electrode potentials of the anodes the same. In addition, in the circuit configuration shown in FIG. 20, the potential loss from the cathode side branch must also be controlled. However, it is necessary to supply power to the wafer that is the cathode by pressing the electrode metal against the wafer surface. In this case, it is difficult to stably control the contact resistance between batches. That is, in order to strictly align the electrode potentials of the anodes 13a to 13c, the resistances of the wiring and the connection portion are made equal, and as a result, stray current can be eliminated and the variation in film thickness between the wafers is reduced. I was able to.

  By the way, in the first embodiment described above, local stirring using the paddle 18 and overall stirring using the stirrer 19 are performed, but FIG. 8 shows the case where the paddle 18 is not used. It is a figure which shows the metal surface result after plating in. During the plating, if suspended matter or bubbles adhere to the metal surface, if the deposit is not electrically conductive, the deposition of the metal stops at that part, and if the deposit is conductive, metal is deposited on it. It will precipitate. As a result, the unevenness of the metal surface after plating becomes large, resulting in a surface as shown in FIG.

  On the other hand, in the first embodiment, the paddle 18 does not attach or remove the suspended matter or bubbles in the plating solution even if it adheres to the wafer surface. In the region E1, floating substances that adhere to the wafer surface are removed and trapped, so that a clean and flat surface can be obtained as shown in FIG. 7 as compared to FIG.

  The wafers 14a to 14c arranged on the fixing jigs 12a to 12c are held by the plating jigs shown in FIGS. This plating jig has a base member 42 and a conductive component 43. The base member 42 is formed with a circular recess 42a in plan view, and the wafer 14a is accommodated in the recess 42a. The base member 42 may be an insulating member. For example, a fluorine resin such as vinyl chloride or Teflon (registered trademark) or a metal coated with a fluorine resin.

  As shown in FIG. 10, the conductive component 43 has a base 43a of a plate-like body having a narrow width in plan view, and a contact portion 43b fixed to one end thereof and in contact with the wafer 14a. The conductive component 43 is fixed to the screw hole of the peripheral edge portion 42b of the base member 42 by a screw 50 through an attachment hole 43c formed at the other end of the base portion 43a of the plate-like body.

  In the case of this conductive part 43, the base 43a, which is a plate-like body, is made of an elastic material, and the plate-like body functions like a leaf spring by narrowing the width of the plate-like body. Can be made. In addition to the conductive component 43, for example, as shown in FIG. 11, a tapered elastic plate-like body 46b having a mounting hole 46c and a small area contact portion 46a is bent at two locations as a conductive component 46. Also good.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. In the second embodiment, a dielectric member is further provided between the wafer and the anode with respect to the electroplating apparatus of the first embodiment, and the shape of the dielectric member is adjusted in accordance with the shape of the wafer. The electric field on the surface is controlled to form a uniform plating film.

  FIG. 12 is a schematic diagram showing a partial configuration of an electroplating apparatus according to Embodiment 2 of the present invention. As shown in FIG. 12, in this electroplating apparatus, a dielectric member 60 is provided on the anode 14b side between the wafer 14b and the anode 13b. When the shape of the wafer 14b is circular, the opening shape formed by the dielectric member 60 is a circle having a slightly smaller diameter than the circle of the wafer 14b. The dielectric member 60 controls the electric field on the surface of the wafer 14b by the electric field shielding effect of the dielectric, and the shape of the dielectric member 60 is optimized by experiment or simulation.

  In the second embodiment, it is assumed that a plurality of wafers are plated simultaneously in the same plating bath. However, by providing this dielectric member 60, stray current is suppressed, and plating efficiency is improved. The variation between them is further reduced, and the effect of keeping stable can be obtained. This is because, in the second embodiment, the stray current is almost negligible because it is canceled out between the electrodes. However, the stray current flowing from the anode is a current that does not contribute to the plating on the opposite wafer, thus reducing the plating efficiency. If the balance that is offset by any cause is lost, the plating results will vary, and should be suppressed as much as possible. Most of the stray current flows from the surface of the portion of the anode that is not restrained by the electric field with the wafer, and such a portion does not need to be exposed. For this reason, by covering a portion where the anode is not required to be exposed with a dielectric member, an optimized electric field toward the opposite wafer is formed intensively, and stray current is suppressed.

  The material of the dielectric member 60 that functions as a shielding plate is a fluororesin sheet having a thickness of 0.1 mm, but has chemical durability and heat resistance to plating solutions such as vinyl chloride, polypropylene, polyethylene, polystyrene, etc. If available, it can be used. In the second embodiment, an opening concentric with the wafer 14b is provided at the center of the dielectric member 60 and is optimized by an experiment in which the size is changed. It is also possible to use one that has been optimized with a shape such as changing or opening an infinite number of holes and continuously changing the aperture ratio concentrically.

  Here, the result of optimization of the dielectric member 60 will be described with reference to FIG. The wafer 14b is 4 inches, the anode 13b is a substantially disc-shaped punching metal having a diameter of about 160 mm, and the distance between the anode 13b and the wafer 14b is about 20 mm in consideration of the passage of the paddle 18. The uniformity is a percentage obtained by dividing the standard deviation 3σ of the film thickness variation by the average film thickness T.

  FIG. 13 shows the in-plane uniformity of the 4-inch wafer 14b with the opening diameter of the dielectric member 60 changed and the approximate distribution shape of the plating film at that time. As shown in FIG. 13, when the opening diameter of the dielectric member 60 was about 3 inches, the in-plane uniformity was the lowest at about 15%, and the distribution shape was almost flat, although the peripheral edge was slightly thicker. From this result, it is determined that the dielectric member 60 having an opening with a diameter of 3 inches at the center is optimal for a 4-inch wafer substrate.

  In the second embodiment, a 4-inch wafer is used as an object to be plated. However, by reducing the opening diameter of the dielectric member 60, for example, a 3-inch, 2-inch, or rectangular wafer can be handled. Is also possible. As described above, if the wafer has a size equal to or smaller than that of the anode, it is possible to cope with wafers having various shapes only by changing the shape of the dielectric member 60.

(Embodiment 3)
Next, a third embodiment of the present invention will be described. In the first and second embodiments described above, the anode is installed independently for each wafer. However, in this third embodiment, the anode potential is equal so that each wafer has one common anode. It is trying to become.

  FIG. 14 is a plan view showing an outline of an electroplating apparatus according to Embodiment 3 of the present invention. FIG. 15 is a perspective view of the electroplating apparatus shown in FIG. 14 and 15, in this electroplating apparatus, a plurality of wafers 74a to 74f are immersed in a plating bath, and a mesh-like anode 73 is disposed on the outer periphery thereof. Since the anode 73 is integrated, the electrode potential is uniform. Each of the wafers 74a to 74f is individually connected to the cathode 73, and the current value flowing through the anode 73 is controlled by the controller C. As a result, the same circuit as the electric circuit system shown in FIG. 6 is easily formed.

  In the third embodiment, since the plating surfaces of the wafers 74a to 74f are vertically oriented, the influence of floating substances during plating can be reduced, and the precipitation effect of the floating substances can be further increased.

  Moreover, as long as the electrode potential of the anode is constant, it may be provided independently in the plating bath. For example, as shown in FIG. 16, the anode 73 may be provided independently as anodes 73a to 73f corresponding to the wafers 74a to 74f. Note that the paddle corresponding to the paddle 18 stirs between each wafer and the anode.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described. In the fourth embodiment of the present invention, a configuration in which the surface of the plating solution is further covered with an inert gas atmosphere is added to the configurations of the first to third embodiments of the present invention described above.

  FIG. 17 is a schematic diagram showing a configuration of an electroplating apparatus according to Embodiment 4 of the present invention. In FIG. 17, a gas source 81 and a lid 80 that covers the plating bath are further provided in the configuration of the first embodiment. Nitrogen gas as an inert gas is sent from the gas source 81 to the space defined by the lid 80, and this space is used as a slight positive pressure to prevent air from entering from the atmosphere. As a result, the plating solution surface is covered with an inert gas atmosphere, so that oxidation of the plating solution is prevented. In addition, it may be sealed using an O-ring or the like and completely isolated from the atmosphere.

  When the surface of the plating solution is covered with nitrogen gas in this manner, the oxidation of the plating solution is prevented. For example, when plating on three 4-inch wafers using a sulfurous acid-based plating solution was continued and exposed to the atmosphere, abnormalities such as rough metal surfaces were observed after about 15 times. When the plating solution surface was covered with nitrogen gas, the metal surface could be used up to about 30 meetings without being roughened.

  In the first to third embodiments described above, it is assumed that plating is performed on a plurality of wafers in one plating bath without circulating the plating solution outside the plating bath during plating. Not limited to this, one wafer may be plated in one plating bath.

It is a schematic diagram which shows schematic structure of the electroplating apparatus which is embodiment of this invention. It is a perspective view which shows schematic structure of the electroplating apparatus shown in FIG. It is a schematic diagram which shows the structure of the anode and cathode vicinity of the electroplating apparatus shown in FIG. It is a schematic diagram which shows the plating state of the wafer surface vicinity by turbulent flow. It is a schematic diagram which shows the plating state of the wafer surface vicinity in the case of not performing turbulent flow. It is a circuit diagram which shows the electric circuit system of the electroplating apparatus shown in FIG. It is a figure which shows the wafer surface at the time of plating using the electroplating apparatus shown in FIG. It is a figure which shows the wafer surface at the time of plating using the conventional electroplating apparatus. It is a top view which shows the structure of the jig | tool for plating holding a wafer. It is a perspective view which shows the structure of the electroconductive component of the jig | tool for plating. It is a perspective view which shows the structure of another electroconductive component. It is a schematic diagram which shows the structure of the anode and cathode vicinity of the electroplating apparatus which is Embodiment 2 of this invention. It is a figure which shows the uniformity of a plating film in case the opening diameter of a dielectric material is changed, and the outline distribution shape of a plating film. It is a top view which shows schematic structure of the electroplating apparatus which is Embodiment 3 of this invention. It is a perspective view which shows schematic structure of the electroplating apparatus shown in FIG. It is a top view which shows schematic structure of the electroplating apparatus which is a modification of Embodiment 3 of this invention. It is a schematic diagram which shows schematic structure of the electroplating apparatus which is Embodiment 4 of this invention. It is a circuit diagram which shows the electric circuit system of the conventional electroplating apparatus. It is a circuit diagram which shows the other example of the electric circuit type | system | group of the conventional electroplating apparatus. It is a circuit diagram which shows the other example of the electric circuit type | system | group of the conventional electroplating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electroplating apparatus 10 Plating container 11 Plating solution 12a-12c Fixing jig 13a-13c, 73, 73a-73f Anode 14a-14c, 74a-74f Wafer 15a-15c Variable power supply 16a-16c Ammeter 17 Motor 18 Paddle 19 Stirring Element 20 Stirrer rotating part 21 Heater 22 Thermocouple 42 Jig for plating 43, 46 Conductive part 60 Dielectric member 80 Lid 81 Gas source C Controller

Claims (10)

An electroplating apparatus that circulates a plating solution in one plating bath and energizes between an object to be plated as a cathode and an electrode as an anode to perform electroplating on the object to be plated,
Local stirring means for stirring the plating solution in the vicinity of the surface of the object to be turbulent and making it turbulent;
An overall stirring means for stirring the entire plating solution in the plating bath;
An electroplating apparatus comprising:   The overall stirring means slows down the flow rate at the bottom of the plating bath as compared to the flow rate in the vicinity of the object to be plated, and forms a stagnation region in which the suspended matter in the plating bath is precipitated at the bottom of the plating bath. The electroplating apparatus according to claim 1. An electroplating apparatus for simultaneously plating each object to be plated in a state where a plurality of objects to be plated are arranged in the same plating bath,
A plurality of variable power supplies connected in common to the electrode serving as the anode and supplying current to each object to be plated serving as the cathode;
Control means for controlling the current value supplied from each variable power source to equalize the potential of the anode electrode;
An electroplating apparatus comprising: Local stirring means for stirring and turbulent plating solution in the vicinity of the surface of the object to be plated;
An overall stirring means for stirring the entire plating solution in the plating bath;
The electroplating apparatus according to claim 3, further comprising:   The overall stirring means slows down the flow rate at the bottom of the plating bath as compared to the flow rate in the vicinity of the object to be plated, and forms a stagnation region in which the suspended matter in the plating bath is precipitated at the bottom of the plating bath. The electroplating apparatus according to claim 4, wherein the electroplating apparatus is characterized.   The electroplating apparatus according to claim 1, wherein the electrode serving as the anode and the semiconductor wafer serving as the object to be plated are disposed substantially in parallel.   The electroplating apparatus according to claim 6, wherein the semiconductor wafer as the object to be plated is installed substantially horizontally upward or substantially horizontally downward.   The electroplating apparatus according to claim 1, wherein the semiconductor wafer as the object to be plated is disposed on the same horizontal plane.   The electroplating apparatus according to claim 1, wherein a dielectric member corresponding to a shape of the object to be plated is installed between the object to be plated and the anode.   The electroplating apparatus according to any one of claims 1 to 9, wherein a surface of the plating solution is covered with an inert gas atmosphere.