JP3877910B2 - Plating equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plating apparatus suitable for use in plating a substrate to be plated such as a semiconductor wafer.
[0002]
[Prior art]
In recent years, a metal plating apparatus such as copper plating is used to fill the groove or hole of a substrate to be plated in which fine grooves or holes for wiring are formed on the surface of a semiconductor wafer or the like. A technique to fill holes is used. Conventionally, as this type of plating apparatus, there is a face-down type jet plating apparatus. In this plating apparatus, as shown in FIG. 10, a substrate W such as a semiconductor wafer is placed on an upper part of a plating tank 200 with a surface to be plated facing downward (the substrate W to be plated is held by a substrate holding unit 220. The plating solution in the plating solution storage tank 203 is ejected from the bottom of the plating tank 200 through the plating solution supply pipe 207 by the pump 205, and through the holes or meshes provided in the anode plate 211, Plating is performed by bringing a jet of plating solution into contact with the center of the surface perpendicularly.
[0003]
The plating solution overflowed from the plating tank 200 is collected by the plating solution receiver 209 disposed outside the plating tank 200 and returned to the plating solution storage tank 203. Then, by applying a predetermined voltage E between the anode plate 211 and the substrate to be plated W, a plating current flows between the anode electrode 211 and the substrate to be plated W, and a plating film is formed on the surface to be plated of the substrate to be plated W. The
[0004]
However, in the above conventional jet type plating apparatus, the jet flows through one or a plurality of holes or meshes provided in the anode plate 211 to the surface to be plated of the substrate W to be plated. When the film is used, there is a problem in that the peeled piece of the black film attached to the surface of the anode plate 211 is transported to the surface to be plated together with the plating solution, and the plating quality is deteriorated.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and the object thereof is a plating apparatus capable of preventing a decrease in plating quality due to particles caused by a black film or the like even if it is a plating apparatus using a soluble anode electrode. Is to provide.
[0006]
[Means for Solving the Problems]
  In order to solve the above problems, the present invention provides an anode electrode in a plating tank, and flows a plating solution into the plating tank.At the same time as overflowing from the upper edge of the plating tank and installed at the position of the plating solution surface in the plating tankOn the plating surface of the substrate to be platedAboveContact the jet of plating solutionAndIn a plating apparatus for performing plating by energizing between the anode electrode and the substrate to be plated,The anode electrode is composed of a soluble electrode plate, and is installed below the plating solution outlet into the plating tank,A part of the plating solution that has flowed into the plating tank, a through hole provided in the anode electrode or the periphery of the anode electrodeThrough the outlet located below the anode electrodeIt flows out of the plating tank.
  Further, the invention is characterized in that the plating solution outlet is in the upper center of the anode electrode.
  Further, the present invention provides a plating solution supply unit on the inner peripheral side surface of the plating tank, and installs a partition plate having a hole smaller than the diameter of the substrate to be plated at the upper part of the plating solution supply unit. A part of the plating solution that has flowed into the plating tank from the hole flows toward the substrate to be plated from the hole, and the other part flows out from the outlet to the outside of the plating tank.
  Moreover, the present invention is characterized in that particles are removed by a filter from the plating solution that has flowed out of the plating tank from the outlet.
[0007]
By providing such an outlet, the black film formed on the surface of the anode electrode peels off, and the fine particles can flow out of the plating tank together with the plating solution, and the fine particles are mixed with the plating solution. Thus, it can be prevented from being transported and adhered to the surface to be plated of the substrate to be plated. It is also possible to prevent the deposits on the anode electrode other than the black film and the deposits from adhering to the plated surface of the substrate to be plated.
[0008]
  The present invention also allows the plating solution to flow into the plating tank.At the same time as overflowing from the upper edge of the plating tank and installed at the position of the plating solution surface in the plating tankOn the plating surface of the substrate to be platedAboveContact the jet of plating solutionAndIn the plating method for performing plating by energizing between the anode electrode disposed in the plating tank and the substrate to be plated, a part of the plating solution that has flowed into the plating tank,It is composed of a soluble electrode plate and installed below the plating solution outlet into the plating tank.Around the through-hole or anode electrode provided in the anode electrodeThrough the outlet located below the anode electrodeIt flows out of the plating tank.
[0009]
  In addition, the plating apparatus according to the present invention includes a plating solution injection pipe disposed at a plurality of positions symmetrical to the central axis of the plating tank at positions away from the center of the side wall or bottom surface of the plating tank, and these plating solutions. From the spray tube toward the center of the plating solutionThe plating solution is sprayed so that the central portion of the plating solution rises, while the anode electrode is placed at the bottom of the plating tank,While overflowing the plating solution from the upper part of the plating tank, contact the plating surface of the substrate to be plated with the plating solution surface or immerse it in the plating solution.By energizing between the anode electrode and the substrate to be platedPlating is performed.
[0010]
Thus, it is possible to easily prevent the jet of the plating solution from directly contacting the anode electrode installed in the plating solution. Moreover, the central part of the plating solution surface rises. Raising the central portion of the plating solution surface means that even when the substrate to be plated is immersed in the plating solution and plating, the substrate to be plated is brought into contact with the plating solution before starting plating. It is effective for removing bubbles from between the surface to be plated and the plating solution.
[0011]
  Further, the present invention is arranged at a position away from the center of the side wall or the bottom surface of the plating tank, and the plating solution injection pipes are disposed at a plurality of positions symmetrical with respect to the central axis of the plating tank,On the other hand, the anode electrode is placed at the bottom of the plating tank,While spraying the plating solution from these plating solution injection pipes and overflowing the plating solution from the upper part of the plating tank, the surface to be plated of the substrate to be plated is in contact with the plating solution surface or immersed in the plating solution.By energizing between the anode electrode and the substrate to be platedA plating apparatus for performing plating, wherein the plating solution spraying direction by the plating solution spraying tube intersects with the liquid surface where the plating solution overflows on the side closer to the plating solution spraying tube than the central axis of the plating tank, In the part, it passes through a position separated from the central axis by a distance smaller than ½ of the radius of the substrate to be plated, and the spraying direction of the plating solution by all the plating solution injection pipes is substantially the same angle on the same side toward the central axis. It is characterized by being inclined.
[0012]
This not only makes it easy to prevent the plating solution jet from directly touching the anode electrode installed in the plating solution, but also creates a gentle vortex flow in the plating tank to stabilize the flow. The flow velocity is given to the outer peripheral portion where the flow velocity is reduced, and the flow velocity distribution of the entire surface to be plated is improved. In order to give rotation to the plating solution in a state where the central portion of the plating solution level is raised, the direction of the jet may pass through a position away from the central axis by a distance smaller than 1/2 of the radius of the substrate to be plated. good.
[0013]
Further, the present invention provides a plating apparatus having a structure in which a plating solution injection pipe is attached to the side wall or bottom surface of the plating tank, and a part of the plating solution flowing into the plating tank is disposed in the plating solution inside the plating tank. It has a structure in which it flows out to the outside of the plating tank through a through hole provided in the formed anode electrode or from the periphery of the anode electrode.
[0014]
As a result, the black film formed on the surface of the anode electrode peels off, and the fine particles can flow out to the outside of the plating tank together with the plating solution. It can be prevented from being transported and adhered. It is also possible to prevent the deposits on the anode electrode other than the black film and the deposits from adhering to the plated surface of the substrate to be plated.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overall schematic configuration diagram showing a plating apparatus according to an embodiment of the present invention. As shown in the figure, this plating apparatus is provided with an anode plate (anode electrode) 30 in the center of the lower part of the plating solution in the plating tank 10, and provided with a plating solution injection pipe 35 penetrating in the center of the anode plate 30. In addition, the semiconductor wafer W is held by the substrate holding part 63 so that the semiconductor wafer (substrate to be plated) W is positioned at the position of the plating solution surface of the plating tank 10. Each component will be described below.
[0016]
The plating tank 10 is a substantially cylindrical container having an open upper surface, and the bottom has a tapered shape (conical shape) with a low center. The plating solution injection pipe 35 protrudes from the lowest central portion of the plating tank 10, and an outflow hole 11 through which the plating solution flows out of the plating tank 10 is located around the plating solution injection pipe 35. Is provided. The plating solution flowing out from the outflow hole 11 is returned to the plating solution storage tank 39 through the filter (or separator) 37, and is ejected from the plating solution injection pipe 35 through the pump 41 and the filter 43.
[0017]
On the other hand, a plating solution receiver 13 is provided on the outer periphery of the upper edge portion of the plating tank 10 so as to surround it, and the plating solution in the plating solution receiver 13 is also returned to the plating solution storage tank 39.
[0018]
The anode plate 30 is disposed at the center in the lower part of the plating tank 10 so that the surface thereof is perpendicular to the central axis of the plating tank 10. As the anode plate 30, a soluble electrode plate is used, and in the case of copper plating, phosphorous copper is used. The anode plate 30 of this embodiment is disk-shaped and has an opening 31 through which the plating solution spray pipe 35 passes.
[0019]
On the other hand, a substrate holding unit vertical drive mechanism 57 for raising and lowering the substrate holding unit 63 and a substrate pressing plate vertical driving mechanism 61 for raising and lowering the substrate pressing plate 67 described below are provided above the substrate holding unit 63. The substrate pressing plate vertical drive mechanism 61 is composed of a cylinder driven by spring force in the downward direction and air in the upward direction, and is housed in a frame 61a supported by a motor (rotary drive mechanism) 59, and the air piping is a motor. It passes through the center of the shaft and is connected to the outside by a rotary joint above the motor 59. The motor 59 and the substrate pressing plate vertical drive mechanism 61 are moved up and down by the substrate holding unit vertical drive mechanism 57. Reference numeral 51 denotes a support arm.
[0020]
2 is a cross-sectional view showing a portion of the substrate holding part 63, FIG. 3 is an enlarged cross-sectional view of the main part when the substrate holding part 63 is viewed from a direction orthogonal to FIG. 2, and FIG. It is a principal part expanded sectional view of the 71 part. As shown in these drawings, the substrate holding part 63 has a cylindrical shape with a diameter slightly larger than the diameter of the wafer that can accommodate the semiconductor wafer W therein, and the lower surface has an opening slightly smaller than the wafer diameter, and the upper part is A substrate holding case 65 made of an insulating material that is closed and has a substrate holding portion rotating shaft 68 that supports the substrate holding portion 63 in the center of the upper surface and has a slit-like opening 69 when the semiconductor wafer W is taken in and out of the side wall. And a disc-shaped substrate pressing plate 67 which is disposed in the substrate holding case 65 and has substantially the same diameter as the wafer diameter. The substrate pressing plate 67 is made of an insulating material, and has a pressing shaft 69 for moving the substrate pressing plate 67 up and down. The pressing shaft 69 extends upward through the substrate holding portion rotating shaft 68. A ring-shaped seal member 71 is provided around the opening on the lower surface of the substrate holding case 65, and the seal member 71 is in close contact with the surface of the semiconductor wafer W to prevent the plating solution from entering. Plural or ring-shaped cathode pins 73 are provided on the inner side of the lower surface of the substrate holding case 65 on the larger diameter side than the seal member 71 so that the cathode pins 73 are in contact with the outer peripheral portion of the surface of the semiconductor wafer W. In order to make the potential of the plating surface of the semiconductor wafer W uniform, the cathode pins 73 are arranged so that the cathode pins 73 are in close contact with the entire outer periphery of the surface of the semiconductor wafer W or in line contact with the semiconductor wafer W. The cathode pins 73 may be formed of a ring-shaped plate, and the inner peripheral portion may be bent toward the semiconductor wafer W to have elasticity. As shown in FIG. 4, an air passage 65b is provided so as to connect the inner side and the outer side of the peripheral edge portion 65a holding the semiconductor wafer W under the substrate holding case 65.
[0021]
On the other hand, the substrate holding part 63 is moved up and down by the substrate holding part vertical drive mechanism 57 as shown in FIG. 1, but at the raised position, the substrate holding part 63 and the semiconductor wafer W held therein are plated liquid in the plating tank 10. In this position, the plated semiconductor wafer W is taken out and an unprocessed semiconductor wafer W is mounted. On the other hand, at the lowered position, the surface to be plated of the semiconductor wafer W is immersed in the plating solution.
[0022]
Then, the removal of the semiconductor wafer W from the substrate holding part 63 raises the substrate holding part 63 to a position where it does not come into contact with the plating solution, and raises the substrate pressing plate 67 to the position shown by the dotted line in FIG. Then, as shown in FIG. 3, the robot hand 75 is inserted from the opening 69 of the substrate holding case 65, the back surface of the semiconductor wafer W is vacuum-sucked and lifted, and the semiconductor wafer W is taken out from the opening 69. On the other hand, the insertion / holding of the semiconductor wafer W to the substrate holding part 63 is performed by conversely vacuum-adsorbing the back surface of the unprocessed semiconductor wafer W with the robot hand 75 and opening the substrate holding case 65 from the opening 69. The semiconductor wafer W is inserted inside, the vacuum suction of the robot hand 75 is released and placed on the seal member 71 and the cathode pin 73, the robot hand 75 is pulled out from the opening 69, and the substrate pressing plate 67 is lowered. This is performed by pushing down the upper part of the semiconductor wafer W and bringing it into contact with the seal member 71 and the cathode pin 73 securely. The vertical movement of the substrate pressing plate 67 is performed by the substrate pressing shaft vertical driving mechanism 61 shown in FIG. The central portion of the opening 69 is greatly opened to allow the robot hand 75 to pass therethrough.
[0023]
Here, when copper is electroplated on the surface of the semiconductor wafer W, since copper easily diffuses into silicon, a metal such as Ti, Ta, TiN, TaN or a compound thereof is used as a barrier layer on the surface to be plated of the wafer. The film is formed, and electrolytic plating is performed using the barrier layer or a thin copper layer formed thereon as a cathode and the anode plate 30 as an anode.
[0024]
The cathode pin 73 for supplying power to the semiconductor wafer W has a risk of damaging the plating layer near the cathode pin 73 when the semiconductor wafer W is taken out when the plating solution comes into contact with the plating solution. Therefore, when the semiconductor wafer W is held by the substrate holding portion 63, the outer peripheral portion of the surface of the semiconductor wafer W is sealed with the sealing member 71 so that the plating solution does not enter, and the cathode pin 73 is connected to the substrate holding case 65 and the semiconductor. The surface of the semiconductor wafer W is brought into contact with a space not touching the plating solution formed by the wafer W and the seal member 71.
[0025]
Conventionally, in the jet plating method in which a plating solution is ejected from the lower side of a plating tank, the semiconductor wafer W is positioned above the plating solution surface of the plating tank with the surface to be plated of the semiconductor wafer W down, and the plating swelled by the jet flow A method of bringing the surface to be plated into contact with the liquid surface has been common. However, in the present embodiment, since the substrate holding part 63 that does not contact the plating solution except for the surface to be plated by the seal member 71 is used, the substrate holding part 63 and the semiconductor wafer W held by the substrate holding part 63 are used as the plating solution. It can be immersed in the plating. Thereby, the distance of a to-be-plated surface and the anode plate 30 can be adjusted freely. It is also possible to move the semiconductor wafer W and the substrate holding part 63 with water by moving the semiconductor wafer W to the outside of the plating tank 10 while being held by the substrate holding part 63.
[0026]
By the way, since the plating solution flow in the plating tank 10 and the electric field between the anode plate 30 and the surface to be plated are not necessarily uniform in the circumferential direction, in order to improve the uniformity of plating, It is effective to rotate the semiconductor wafer W in the plating tank 10 during the electrolytic plating. Therefore, the substrate holder 63 is rotated in the horizontal plane by the motor (rotary drive mechanism) 59 shown in FIG. Another purpose of rotating the semiconductor wafer W is to reduce the concentration diffusion layer near the surface of the semiconductor wafer W by increasing the relative speed of the surface of the semiconductor wafer W and the plating solution, thereby making the plating rate-controlled. This is for the purpose of preventing, forming a uniform plating film on the entire surface, and further increasing the current density to enable high-speed plating.
[0027]
The rotation of the substrate holding part 63 is not limited to the above-described plating, but also removes bubbles when the semiconductor wafer W is attached to the substrate holding part 63 and then comes into contact with the plating solution. After the electrolytic plating is finished, the substrate holding part 63 and the semiconductor wafer W are plated. It is also effective for draining liquid by rotation after raising the liquid level.
[0028]
The rotation of the substrate holding unit 60 during plating is a low-speed rotation of 10 to 300 rpm. After the completion of plating, the substrate holding unit 63 and the semiconductor wafer W are raised to a position where they do not come into contact with the plating solution to perform liquid draining. A rotation of 500 rpm or more (preferably a rotation of 1000 rpm or more) is required.
[0029]
Next, a method for performing plating in the plating tank 10 using the plating apparatus shown in FIG. 1 will be described.
[0030]
First, an unprocessed semiconductor wafer W is mounted on the substrate holder 63 and then the pump 41 is driven to spray the plating solution in the plating solution storage tank 39 from the plating solution injection pipe 35 into the plating tank 10. While rotating the substrate holding part 63 at about 50 to 300 rpm, the semiconductor wafer W is lowered until the semiconductor wafer W comes into contact with the raised plating liquid surface at the center, and the substrate is held more slowly from the state in which the center of the plating liquid contacted the semiconductor wafer W. The part 63 is lowered and electrolytic plating is performed. The descending speed at this time is preferably 30 mm / second or less. Raising the central portion of the plating solution surface means that even when the semiconductor wafer W is immersed in the plating solution for plating, the coating of the semiconductor wafer W is performed at the stage where the semiconductor wafer W is brought into contact with the plating solution before starting the plating. This is effective for removing bubbles from between the plating surface and the plating solution. By doing so, the lower surface of the semiconductor wafer W is filled with the plating solution, and air is discharged from the space between the semiconductor wafer W and the lower part of the substrate holding case 65. In order to discharge this air more efficiently, an air passage 65b shown in FIG. 4 is provided. The air passage 65b is also effective as a liquid discharge passage when the rotating liquid is drained after plating.
[0031]
The sprayed plating solution overflows from the upper edge of the plating tank 10, is collected in the plating solution receiver 13, and flows into the plating solution storage tank 39 through the pipe 15. Further, a part of the plating solution sprayed from the plating solution spray pipe 35 flows out from the outflow hole 11 to the outside of the plating tank 10 through the outer periphery of the anode plate 30, and the black film is formed by the filter (or separator) 37. After removing the exfoliation pieces and the deposits, deposits, etc. on the anode plate 30, they flow into the plating solution storage tank 39. In the embodiment shown in FIG. 1, gravity flows down from the outflow hole 11 to the plating solution storage tank 39, but a pump may be provided between the outflow hole 11 and the filter (or separator) 37.
[0032]
Since the outflow hole 11 is provided in the vicinity of the anode plate 30 as described above, the black film formed on the surface of the anode plate 30 is peeled off, and the fine particles are discharged out of the plating layer 10 together with the plating solution. It is possible to prevent the particles from being mixed with the plating solution and transported to the surface to be plated of the semiconductor wafer W to adhere to the surface to be plated. In addition to the black film, deposits and deposits on the anode plate 30 are also prevented from being transported to the surface to be plated by being jetted and adhering to the surface to be plated.
[0033]
Phosphorus-containing copper anode plate used in copper sulfate electrolytic plating prevents the anode from being passivated by the function of the black film formed on the surface, and suppresses the disproportionation reaction of copper, creating a healthy plating film It plays an important role. However, since this black film peels off from the anode surface and becomes particles, which also affects the abnormal deposition of the plating film, the positional relationship between the anode plate 30 to which the black film adheres and the semiconductor wafer W and the flow of the plating solution therebetween Attention is required. In particular, it is important not to position the surface to be plated downstream of the plating solution that has flowed on the surface of the anode plate 30. The black film is heavier than the plating solution, and most of the debris peeled off from the black film sinks to the bottom of the plating layer 10, and the deposits and deposits on the anode plate 30 other than the black film are also heavier than the plating solution. The hole 11 is desirably provided at a position below the anode plate 30 in the vicinity of the anode plate 30 as in this embodiment, and when the bottom portion of the plating layer 10 has a conical shape as in this embodiment. It is desirable to provide near the lowest point. The plating solution flowing out from the outflow hole 11 is a gentle flow along the surface of the anode plate 30 as much as possible, and the stripped pieces, deposits, deposits, etc. of the black film on the surface of the anode plate 30 together with the flow outflow hole 11. Spill from. Applying a strong flow to the surface of the anode plate 30 is not desirable for promoting the peeling of the black film and keeping the state of the black film stable, and should be avoided.
[0034]
In the above embodiment, the plating solution injection pipe 35 is passed through the center of the anode plate 30, and part of the plating solution flows out of the plating tank 10 from the periphery of the anode plate 30 through the outflow hole 11 below the anode plate 30. However, as shown in FIG. 5, a plurality of through holes 33 are provided in the anode plate 30 itself, and the plating solution that has passed through these through holes 33 flows out of the plating tank 10 from the outflow holes 11. You may do it. Even if comprised in this way, it prevents that the black film peeled off from the surface of the anode plate 30, the deposit | attachment to the anode plate 30, and a deposit get carried to a to-be-plated surface on a jet, and adhere to a to-be-plated surface. it can.
[0035]
If the anode plate 30 is approximately the same size as the surface to be plated of the semiconductor wafer W, the anode plate 30 is a flat surface facing the semiconductor wafer W as shown in FIG. When the distance between the surface to be plated of the semiconductor wafer W and the anode plate 30 is small, it is desirable to make it spherical as shown in FIG.
[0036]
In the embodiment shown in FIGS. 5 and 6, the plating solution injection pipe 35 is disposed near the outer periphery of the bottom surface (which may be a side wall) of the plating tank 10 so that the jet does not directly touch the anode plate 30 ( A plurality (four in the figure) are installed at equal intervals along the circumference at the same height at positions apart from the central axis. The injection direction of the plating solution injection pipe 35 is such that the upper end portion of the plating tank 10 and the direction line of the jet intersect at a side closer to the plating solution injection pipe 35 than the center of the plating tank 10 and slightly lateral from the central axis of the plating tank 10. The direction is shifted in the direction, and the central axis portion of the plating tank 10 passes through a position separated from the central axis by a distance smaller than ½ of the radius of the semiconductor wafer W. Note that the central axis of the semiconductor wafer W coincides with the central axis of the plating tank 10. For all the plating solution injection pipes 35 disposed in the same plating tank 10, the distance between the intersection of the plane in which the plating solution overflows and the injection direction line and the central axis of the plating tank 10 is all the plating solution injection pipes 35. About the direction of the plating solution injection pipe 35 so that the injection direction is shifted by substantially the same angle toward the central axis of the plating tank 10 with respect to all the plating solution injection pipes 35. Adjust. The flow rates of all the plating solution injection pipes 35 are adjusted by a flow rate adjusting valve (not shown) provided in each plating solution injection pipe 35 so as to be substantially equal to each other.
[0037]
By using the plurality of plating solution injection pipes 35, the anode plate 30 can be arranged in the center of the plating tank 10, and the liquid surface center can be raised by the jet flow from the plating solution injection pipe 35, as described above. When the semiconductor wafer W is lowered, the contact of the surface to be plated with the plating solution is gradually expanded, and the bubbles on the lower surface of the semiconductor wafer W can be easily removed.
[0038]
In addition, since the spraying direction of the plating solution by the plating solution spraying pipe 35 is set as described above, a gentle vortex flow is generated in the substantially cylindrical plating tank 10, the flow is stabilized, and the flow rate is reduced only by the jet flow. A flow rate is given to the outer peripheral part of the tank 10, and the flow rate distribution of the whole to-be-plated surface can be improved. If only the plating solution in the plating tank 10 is rotated, it is effective to direct the direction of the jet to the direction along the outer periphery of the plating tank 10 (horizontal plane direction). It becomes high and it is difficult to remove bubbles on the lower surface of the semiconductor wafer W. Therefore, in order to rotate the plating solution in a state where the central portion of the liquid level is raised, the direction of the jet should pass through a position away from the central axis by a distance smaller than ½ of the radius of the semiconductor wafer W as described above. good.
[0039]
Further, as shown in FIG. 7, the plating solution penetrating the anode plate 30 may be allowed to flow out of the plating tank 10 from the outflow hole 11 made of a pipe. In the case of this embodiment, the plating solution injection pipe 35 is installed at the center of the upper portion of the anode plate 30 so that its injection port faces directly above.
[0040]
Even in such a configuration, the black film peeled off from the surface of the anode plate 30 and the deposits and deposits on the anode plate 30 are transported to the plated surface of the semiconductor wafer W and adhered to the plated surface. Can be prevented. Needless to say, the center of the plating solution can be raised.
[0041]
In the embodiment shown in FIG. 8, the plating tank 10 is formed in a substantially cylindrical shape, the peripheral portion of the bottom is tapered so that the center is lowered, the center is substantially flat, and the lower part in the plating tank 10 is centered. A plurality of outflow holes 11 for discharging the plating solution to the outside of the plating tank 10 are provided substantially below the outer periphery of the provided anode plate 30.
[0042]
A plating solution supply unit 45 is provided on the inner peripheral side surface of the plating tank 10, and the inside thereof is partitioned by a porous plate 47, and a plating solution supply pipe 49 is connected to a chamber below the porous plate 47. In the upper chamber partitioned by the perforated plate 47, a second perforated plate 48 facing the inside of the plating tank 10 is provided at the same height along the circumference. Accordingly, the plating solution introduced from the plating solution supply pipe 49 into the plating solution supply unit 45 passes through the perforated plates 47 and 48, is substantially horizontal inside the plating tank 10, and faces the central axis direction of the plating tank 10. Leaked.
[0043]
A partition plate 80 is provided above the second porous plate 48 in the plating tank 10, and one hole 81 having a diameter smaller than the wafer diameter is provided in the center of the partition plate 80. Accordingly, since only the hole 81 provided in the partition plate 80 and the outflow hole 11 on the bottom surface are opened below the partition plate 80, most of the flow rate of the plating solution supplied from the plating solution supply pipe 49 is from the hole 81. It flows toward the semiconductor wafer W. The plating solution rising from the hole 81 of the partition plate 80 supplies a new plating solution to the surface of the semiconductor wafer W and overflows from the upper end of the plating tank 10. The overflowed plating solution is collected by the plating solution receiver 13 as in the above embodiment.
[0044]
On the other hand, a part of the plating solution flows toward the lower anode plate 30 and flows out from the outflow hole 11 on the bottom surface together with the black film peeling pieces and deposits on the surface of the anode plate 30.
[0045]
The means for filtering the overflowed plating solution and the plating solution flowing out from the outflow hole 11 and supplying it to the plating solution supply pipe 49 are the same as the means described in FIG. Further, as the means for holding the semiconductor wafer W, the mechanism described in FIG. 1 (or the mechanism described in FIG. 9 described below) can be used.
[0046]
By the way, the flow from the center to the outer periphery of the surface to be plated of the semiconductor wafer W caused by the jet brings about nonuniformity of the flow velocity in the radial direction, and makes the plating solution vortex around the center of the plating tank or rotates the semiconductor wafer W. Although it has the effect of reducing non-uniformity, it is difficult to completely eliminate it. As a method of making the relative velocity of the surface to be plated and the flow uniform over the entire surface to be plated, there is a method of using a parallel flow along the surface to be plated. Because of the gradient, it is often difficult to achieve parallel flow.
[0047]
On the other hand, it is possible to improve the relative velocity distribution with the plating solution on the entire surface to be plated by causing the semiconductor wafer W to translate and rotate. The translational rotary motion is also called scroll motion, and is a motion that moves the entire semiconductor wafer W in a small circular motion without changing the direction of the semiconductor wafer W itself, and is the same relative to the surroundings at all points on the semiconductor wafer W. It is characterized by having speed. Even in this case, in order to reduce the influence of the flow in the plating tank 10 and the unevenness of the electric field, the substrate holder is rotated slowly around the rotation axis of the substrate holder.
[0048]
An example of a mechanism for this purpose is shown in FIG. This mechanism is configured by attaching a substrate holding unit 110 under the driving unit 100. The substrate holding part 110 is fixed to a rotating plate 113 fixed to a lower part of a rotating shaft 111 provided with L1 as a rotation center so as to be rotatable by a plurality of crankshafts 115. A scroll shaft 117 having a center at a scroll center L2 that is eccentric from the rotation center L1 by the scroll radius is rotatably fixed to the rotation shaft 111. The lower portion of the scroll shaft 117 is centered at a position eccentric from the scroll shaft 117 by the scroll radius, is processed into a cylindrical shape having a larger radius than the scroll shaft 117, and is rotatably fixed to the upper surface of the substrate holder 110. The relative positions of the center of each crankshaft 115 and the center of the scroll shaft 117 are the same relative positions on the upper surface of the rotating plate 113 and the substrate holding case 119. Thus, by rotating the scroll shaft 117 while fixing the rotation shaft 111, the substrate holding case 119 performs a translational rotation motion (scroll motion) around the scroll center. Since the position of the scroll shaft 117 moves when the rotation shaft 111 rotates, the scroll motor 121 that rotates the scroll shaft 117 is fixed to the upper end of the rotation shaft 111 inside the drive unit 100. The substrate pressing shaft 125 for moving the substrate pressing plate 123 up and down passes through the scroll center L2 of the scroll shaft 117, the lower portion is bent in a crank shape within the substrate holding case 119 by a distance equal to the scroll radius, and the lower end is the substrate pressing plate 123. It is fixed so that it can rotate and transmit axial force to the center. The upper part of the substrate presser shaft 125 passes through the scroll shaft 117, transmits axial force and bending moment, but uses two freely rotatable joints and a crankshaft. The upper and lower sides of the presser plate such as an air cylinder arranged on the rotation center L1 Connected to the drive mechanism 127. Accordingly, the pressing force of the presser plate vertical drive mechanism 127 can be transmitted to the substrate presser plate 123 also by scrolling motion. The rotation shaft 111 is driven by a rotation motor 129 in the drive unit 100.
[0049]
In order to bring the center of gravity of the rotating part closer to the center of rotation when the rotating liquid is removed after plating, the stop position of the scroll shaft 117 is controlled so that the center of the substrate holding case 119 overlaps the center of rotation when the scroll is stopped. As this means, an optical sensor or a magnetic sensor may be used to monitor the position of the drive gear of the scroll shaft 117 and control the stop position of the scroll motor 121.
[0050]
The substrate holding unit 110 is moved up and down by moving up and down a moving frame 133 that holds each drive mechanism and bearing in the drive unit 100 by the vertical drive mechanism 131. In FIG. 9, the vertical movement amount is shown with a small amount, but in actuality, a movement prevention amount of about 100 mm is necessary to provide a splash prevention cover at the upper part of the plating tank. The movement by the vertical drive mechanism 131 needs to stop at three positions, ie, the immersion position of the semiconductor wafer W, the position of rotating the liquid on the plating liquid surface, and the position of taking out the wafer, and slowly descend while rotating at the time of liquid contact before the start of plating. Therefore, the vertical drive mechanism 131 is a controllable mechanism corresponding to these.
[0051]
The mechanism for holding the semiconductor wafer W using the substrate holding case 119, the substrate pressing plate 123, the seal member, and the cathode pins is substantially the same as that in FIG. Reference numeral 135 denotes a substrate outlet. The wiring for connecting the cathode pin and the power source passes through the wall of the substrate holding case 119 and is transmitted to the substrate presser shaft 125 by a slidable slip ring, and the same slidable slip provided on the presser plate vertical drive mechanism 127. It is taken out by a ring and connected to a power source cathode (not shown).
[0052]
In each of the above embodiments, a semiconductor wafer is used as a substrate to be plated. However, it goes without saying that it may be used for plating of other various substrates.
[0053]
【The invention's effect】
  As described above in detail, the present invention has the following excellent effects.
  (1)Claim 1,5As described in the above, since a part of the plating solution that has flowed into the plating tank is allowed to flow out of the plating tank from the periphery of the through-hole or anode electrode provided in the anode electrode, As a result, the plating quality is improved and the yield is improved. Moreover, the uniformity of the plating film thickness can be improved.
[0054]
  (2)Claim6Since the plating solution injection tube is installed as described in 1., the central portion of the plating solution surface can be raised to effectively remove bubbles from between the plating surface of the substrate and the plating solution, and the anode installed in the plating solution It is easy to prevent the jet of plating solution from directly touching the electrode.
[0055]
  (3)Claim7The plating solution injection tube is installed as described in 1. As a result, the flow can be stabilized, and the flow velocity can be given to the outer peripheral portion where the flow velocity is lowered only by the jet flow, thereby improving the flow velocity distribution of the entire surface to be plated.
[Brief description of the drawings]
FIG. 1 is an overall schematic configuration diagram showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a portion of a substrate holder 63. FIG.
3 is an enlarged cross-sectional view of a main part when a substrate holding part 63 is viewed from a direction orthogonal to FIG.
4 is an enlarged cross-sectional view of a main part of a seal member 71. FIG.
FIG. 5 is a diagram showing another embodiment.
FIG. 6 is a diagram showing another embodiment.
FIG. 7 is a diagram showing another embodiment.
FIG. 8 is a diagram showing another embodiment.
FIG. 9 is a diagram illustrating an example of a mechanism that translates and rotates a semiconductor wafer W;
FIG. 10 is a view showing a conventional plating apparatus.
[Explanation of symbols]
10 Plating tank
11 Outlet
30 Anode plate (anode electrode)
33 Through hole
35 Plating solution injection pipe
63 Substrate holder
W Semiconductor wafer (substrate to be plated)

Claims (8)

An anode electrode is disposed in the plating tank, and the plating solution is allowed to flow into the plating tank and overflow from the upper edge of the plating tank. At the same time, the substrate to be plated placed at the position of the plating liquid surface in the plating tank is covered. abut the jet of the plating solution to the plating surface in the plating apparatus for performing plating by energizing between the anode electrode and the object to be plated substrate,
The anode electrode is composed of a soluble electrode plate, and is installed below the plating solution outlet into the plating tank,
A part of the plating solution that has flowed into the plating tank flows out of the plating tank from a through hole provided in the anode electrode or an outlet provided at a position below the anode electrode through the periphery of the anode electrode. Plating equipment. 2. The plating apparatus according to claim 1, wherein the plating solution outlet is located in the upper center of the anode electrode. A plating solution supply unit is provided on the inner peripheral side surface of the plating tank, and a partition plate having a hole smaller than the diameter of the substrate to be plated is installed on the upper part of the plating solution supply unit. 2. The plating apparatus according to claim 1, wherein a part of the plating solution that has flowed out flows from the hole toward the substrate to be plated, and another part flows out from the outlet to the outside of the plating tank. The plating apparatus according to claim 1, wherein particles are removed from the plating solution that has flowed out of the plating tank from the outlet through a filter. Abutting a jet of said plating solution to be plated surface of the plated substrate placed in the position of the plating liquid surface of the plating solution at the same time the plating tank when the overflow from the upper edge of the inlet to the plating tank into the plating tank In the plating method of plating by energizing between the anode electrode and the substrate to be plated disposed in the plating tank,
A part of the plating solution that has flowed into the plating tank is a through-hole or anode electrode that is made of a soluble electrode plate and provided in an anode electrode that is disposed below the plating solution outlet into the plating tank. A plating method, characterized by causing the outside to flow out of the plating tank from an outlet provided at a position below the anode electrode through the periphery. The plating solution injection pipes are disposed at a plurality of positions symmetrical to the central axis of the plating tank at positions away from the center of the side wall or bottom surface of the plating tank, and from the plating solution injection pipes to the center of the plating solution surface. The plating solution is sprayed so that the central portion of the plating solution surface rises toward the surface. On the other hand, the anode electrode is placed at the bottom of the plating tank, and the plating solution overflows from the top of the plating tank. A plating apparatus for performing plating by contacting a plating surface with a plating solution surface or dipping in a plating solution and energizing between an anode electrode and a substrate to be plated . The plating solution injection pipes are disposed at a plurality of positions symmetrical to the central axis of the plating tank at positions away from the center of the side wall or bottom surface of the plating tank, while the anode electrode is disposed at the lower part of the plating tank. While injecting the plating solution from the plating solution injection pipe and overflowing the plating solution from the upper part of the plating tank, the surface to be plated is in contact with the surface of the plating solution or immersed in the plating solution and the anode electrode and the substrate to be plated It is a plating apparatus that performs plating by energizing in between ,
The spraying direction of the plating solution by the plating solution spraying tube intersects the surface of the plating solution overflowing on the side closer to the plating solution spraying tube than the central axis of the plating tank, and the central axis part is 1 / of the radius of the substrate to be plated. It passes through a position separated from the central axis by a distance less than 2, and the plating solution injection directions of all the plating solution injection pipes are inclined at substantially the same angle toward the same side toward the central axis. Plating equipment. Part of the plating solution that has flowed into the plating tank has a structure that flows out through the through hole provided in the anode electrode disposed in the plating solution inside the plating tank or from the periphery of the anode electrode to the outside of the plating tank. The plating apparatus according to claim 6 or 7, wherein:

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