JP2008121062A - Plating device and plating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating device and a plating method capable of enhancing the uniformity of a plated film thickness and the uniformity of a plated film surface by controlling the current density distribution in a plating tank uniformly and regulating the flow of a plating solution. <P>SOLUTION: The plating device is equipped with: a resistor holder 60 for holding a resistor R installed so as to shield the plating solution Q held in a plating unit 30 to the anode 10 side and the substrate W side; a shield 170 for shielding an electrical path not passing through the resistor R; plating solution jetting ports 183A, B for jetting the plating solution to a gap S1 between the substrate W and the resistor R to flow the solution through the gap S1; and plating solution circulation systems 250, 260 for circulating the plating solution through the anode area A2 partitioned by the resistor R and the resistor holder 60 and a substrate area A1, respectively. A partition member is provided in an overflow tank 40 to shield between the plating solutions overflowing from each of the substrate area A1 and the anode area A2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is, for example, a plating apparatus that performs plating on the surface (surface to be plated) of a substrate, in particular, forming a plating film in fine trenches, via holes, resist openings provided on the surface of a semiconductor wafer or the like, The present invention relates to a plating apparatus and a plating method suitable for use in forming bumps (projection-like connection electrodes) that are electrically connected to a power source of a package on the surface.

  Conventionally, for example, in TAB (Tape Automated Bonding) and FC (flip chip), gold, copper, solder, lead-free solder, nickel, and the like are provided at predetermined positions (electrodes) on the surface of a semiconductor chip on which wiring is formed. It is widely practiced to form projecting connection electrodes (bumps) that are laminated in multiple layers and to be electrically connected to package electrodes and TAB electrodes via the bumps. There are various bump forming methods, such as plating, vapor deposition, printing, and ball bump. However, as the number of I / Os in semiconductor chips increases and the pitch decreases, miniaturization is possible and performance is improved. A plating method that is relatively stable is increasingly used. In particular, the metal film obtained by electroplating is characterized by high purity, high film formation speed, and simple film thickness control method.

  FIG. 16 is a schematic configuration diagram showing an example of a conventional electroplating apparatus 300 using a so-called dip method. As shown in the figure, this electroplating apparatus 300 has a plating tank 301 that holds a plating solution Q therein, and the substrate W and the peripheral edge and the back surface of the substrate W are sealed in a watertight manner (surface to be plated). A substrate holder 310 that exposes and detachably holds, an anode 340, an anode holder 350 that holds the anode 340 and faces the substrate W, and a central hole 330 that is installed between the anode 340 and the substrate W and that has a central hole 330 in the center. An adjustment plate (regulation plate) 320 made of a dielectric material is dipped. Then, the anode 340 is connected to the anode of the plating power source 360 via the lead wire 370a, and the substrate W is connected to the cathode of the plating power source 360 via the lead wire 370b, so that the potential difference between the substrate W and the anode 340 causes a difference in the plating solution Q. The metal ions receive electrons from the surface of the substrate W, and the metal is deposited on the substrate W to form a metal film.

  According to this plating apparatus 300, since the adjusting plate 320 having the central hole 330 is disposed between the anode 340 and the substrate W, the potential distribution in the plating tank 301 can be adjusted by the adjusting plate 320. The film thickness distribution of the metal film formed on the surface of the substrate W can be adjusted to some extent.

On the other hand, semiconductor substrates (wafers) tend to have a large area year by year, and there have been problems associated therewith. In other words, in the case of a large-area substrate, the electrical resistance of the conductive layer from the cathode connected to the vicinity of the outer periphery of the substrate to the center of the substrate increases, causing a potential difference in the plane of the substrate, and there is a difference in the plating speed of each part of the substrate. It will occur. FIG. 17 shows a typical equivalent circuit of electrolytic plating, and the following resistance components exist in the circuit.
R1: Power line resistance and various contact resistances between the power supply 360 and the anode 340 R2: Polarization resistance at the anode 340 R3: Resistance of the plating solution Q R4: Polarization resistance at the cathode 400 R5: Resistance of the conductive layer R6: With the cathode 400 Power line resistance and various contact resistances with the power source 360

  As is clear from FIG. 17, when the resistance R5 of the conductive layer is larger than the other electric resistances R1 to R4 and R6, the potential difference generated at both ends of the resistance R5 increases, and accordingly, the plating currents at various parts of the substrate are increased. There will be a difference. For this reason, the growth rate of the plating film decreases at a position far from the cathode 400. This means that the current density is different in the plane of the substrate W, and the characteristics of the plating film itself (the resistivity, purity, embedding characteristics, etc. of the plating film) are not uniform in the plane.

  In order to prevent this drawback, a high resistance structure 430 having an electric conductivity smaller than the electric conductivity of the plating solution Q is disposed between the anode 340 and the substrate W as shown in FIG. Yes. With this configuration, the resistance Rp due to the high resistance structure 430 is added as compared with the equivalent circuit shown in FIG. 17, and therefore when the resistance Rp due to the high resistance structure 430 becomes a large value, (R2 + R3 + Rp + R4) / ( R2 + R3 + Rp + R4 + R5) approaches 1 and is less affected by the resistance component R5, that is, the resistance component due to the conductive layer, so that there is little difference in the plating current at each part of the substrate.

By the way, in recent high-density mounting technologies such as SOC and WL-CSP, there is an increasing demand for high-precision uniformity of the surface shape and film thickness of the metal film formed over the entire surface of the substrate. However, with the conventional plating method, it has been very difficult to form a metal film that responds to high-precision uniformity. Further, for example, while preventing a defect such as a void from being generated inside a via hole having a high aspect ratio and a depth of about 10 to 20 μm and a depth of about 70 to 150 μm provided inside the substrate. In addition, it is not only difficult to reliably embed a metal film by plating, but it takes a lot of time.
JP 2004-225129 A JP 2003-258591 A

  The present invention has been made in view of the above points, and its purpose is to more uniformly adjust the current density distribution in the plating tank, and further adjust the flow of the plating solution, thereby achieving uniform plating film thickness and plating surface. An object of the present invention is to provide a plating apparatus and a plating method that can further improve the uniformity of the film.

  The invention according to claim 1 of the present application holds the plating solution, stores the substrate, the resistor, and the anode in this plating solution in this order, and energizes between the substrate and the anode so that the surface to be plated is provided. A plating tank having a plating unit for performing plating, an overflow tank for accommodating the plating unit therein, a substrate holder for holding the substrate and bringing the surface to be plated into contact with the plating solution, and in the plating unit A resistor holder having an opening for holding the resistor, and the resistor out of the electrical path between the anode and the substrate. And a plurality of plating solution injection holes for injecting the plating solution into the gap between the substrate and the resistor and flowing the plating solution into the gap. A plating solution circulation mechanism, and a plating solution circulation system for circulating the plating solution in each of the anode region and the substrate region defined by the resistor and resistor holder in the plating unit, and further in the overflow tank In the plating apparatus, a partition member is provided to block the plating solution overflowing from the anode region and the plating solution overflowing from the substrate region.

  In the invention according to claim 2 of the present application, the plating solution circulation mechanism is configured such that the plating solution is injected into the gap between the substrate and the resistor by the plating solution injection port, and the plating solution filled in the gap. The plating apparatus according to claim 1, wherein the plating solution is circulated through the gap by discharging.

  The invention according to claim 3 of the present application is characterized in that the plurality of plating solution injection holes are arranged around the opening of the resistor holder or along the outer periphery of the substrate. 2 in the plating apparatus.

  In the invention according to claim 4 of the present application, the plating solution injection port is formed such that the plating solution injected from the plating solution injection port is linear or toward the center of the surface to be plated of the substrate held by the substrate holder. The plating apparatus according to any one of claims 1 to 3, wherein the plating apparatus is configured to flow in a fan shape.

  The invention according to claim 5 of the present application is characterized in that the plating solution circulation mechanism has a switching mechanism for switching the plurality of plating solution injection ports and injecting the plating solution from all or a part of the plurality of plating solution injection ports. The plating apparatus according to any one of claims 1 to 4, wherein:

  The invention according to claim 6 of the present application is the plating apparatus according to any one of claims 1 to 5, wherein the substrate holder is attached in close contact with the resistor holder by a clamper. is there.

  According to the seventh aspect of the present invention, the surface of the substrate held by the substrate holder is disposed in contact with the plating solution in the plating unit, and the anode is opposed to the surface of the substrate to be plated. A resistor holder that is immersed in the plating solution and has an opening and holds the resistor in the opening is shielded between the substrate and the anode from the plating solution in the plating unit. And a plurality of plating solution injection ports for injecting and circulating the plating solution into the gap between the substrate and the resistor, and from the plating solution injection port to the center of the surface to be plated of the substrate While the plating solution is sprayed toward the surface, the plating solution filled in the gap is discharged to the outside of the gap, and a plating current is passed between the anode and the substrate to perform plating on the surface to be plated. In the plating method comprising.

  The invention according to claim 8 of the present application is characterized in that the plurality of plating solution injection holes are arranged around the opening of the resistor holder or along the outer periphery of the substrate. In the plating method.

  The invention according to claim 9 of the present application is characterized in that the plating solution injected from the plating solution injection port flows in a straight line shape or a fan shape toward the center of the surface to be plated of the substrate held by the substrate holder. The plating method according to claim 7 or 8.

  The invention described in claim 10 is characterized in that the plating solution is ejected from all or a part of the plurality of plating solution ejection ports by switching the plurality of plating solution ejection ports from which the plating solution is ejected. It exists in the plating method in any one of Claim 7 thru | or 9.

  The invention according to claim 11 of the present application is the plating method according to any one of claims 7 to 10, wherein the substrate holder is attached in close contact with the resistor holder by a clamper. is there.

According to the first aspect of the present invention, since the resistor having a high current rectifying function is used, the current density on the surface to be plated of the substrate can be made uniform, and the plating film thickness can be made uniform.
In addition, since the plating solution is sprayed from the plating solution injection port into the gap between the substrate and the resistor, and the plating solution in this gap is stirred and distributed, the plating solution can be easily used even if the gap between the substrate and the resistor is narrow. Can be stirred and distributed, and the uniformity of the plating surface can be achieved. This is particularly effective when the distance between the substrate and the resistor is less than 6 mm.
In addition, the plating solution held in the plating unit by the resistor holder is shut off to the anode side and the substrate side, and the electrical path that does not pass through the resistor is shut off by a seal, and further in the anode region and the substrate region in the plating unit. Since the plating solution circulation system that circulates the plating solution and the partition member in the overflow tank are provided to insulate the anode side plating solution from the cathode side plating solution, current leaks to the current path other than the resistor. From this point, the current density on the surface to be plated of the substrate can be made uniform, and the plating film thickness can be made uniform.

  According to the second aspect of the present invention, the plating solution injected from the plating solution injection port into the gap between the substrate and the resistor can be smoothly discharged to the outside. Distribution is good.

  According to the invention described in claims 3 and 4 of the present application, since the plating solution sprayed from the plating solution spray port is directed from the periphery of the surface to be plated of the substrate toward the center, the substrate is not circulated around the resistor. The plating solution can be surely poured into the gap between the resistor and the resistor, and the plating solution can be distributed without stagnation over the entire surface to be plated of the substrate.

  According to the fifth aspect of the present invention, a random flow can be given to the plating solution, and the uniformity of the plating surface can be further improved.

  According to the sixth aspect of the present invention, the substrate holder can be easily attached to and detached from the resistor holder, and the substrate can be easily positioned with respect to the resistor. Also, by tightly bonding and integrating them, the gap formed between the substrate holder and resistor holder can be easily configured in a sealed structure or a structure close to a sealed state, preventing the plating solution from wrapping around the resistor It is possible to reliably pass the plating solution between the substrate and the resistor.

According to the seventh aspect of the present invention, since the resistor having a high current rectifying function is used, the current density on the surface to be plated of the substrate can be made uniform, and the plating film thickness can be made uniform.
In addition, since the plating solution is sprayed from the plating solution injection port into the gap between the substrate and the resistor, and the plating solution in this gap is stirred and distributed, the plating solution can be easily used even if the gap between the substrate and the resistor is narrow. Can be stirred and distributed, and the uniformity of the plating surface can be achieved.

  According to the invention described in claims 8 and 9 of the present application, since the plating solution sprayed from the plating solution spray port is directed from the periphery of the surface to be plated of the substrate toward the center, the substrate is not circulated around the resistor. The plating solution can be surely poured into the gap between the resistor and the resistor, and the plating solution can be distributed without stagnation over the entire surface to be plated of the substrate.

  According to the invention described in claim 10 of the present application, a random flow can be given to the plating solution, and the uniformity of the plating surface can be further improved.

  According to the invention of claim 11 of the present application, the substrate holder can be easily attached to and detached from the resistor holder, and the substrate can be easily positioned with respect to the resistor. In addition, by closely adhering and integrating the two, the gap formed between the substrate holder and resistor holder can be configured to have a sealed structure or a structure close to the sealed state, preventing the plating solution from wrapping around the resistor. It is possible to reliably pass the plating solution between the substrate and the resistor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overall schematic configuration diagram of a plating apparatus 1-1 according to an embodiment of the present invention, and FIG. 2 is an anode 10, a plating unit 30 and an overflow tank 40 among components constituting the plating apparatus 1-1. It is the schematic plan view which looked at the substrate holder 50 and the resistor holder 60 from the upper direction. In this embodiment, the present invention is applied to a dip bump plating apparatus. As shown in FIG. 1, the plating apparatus 1-1 includes a plating unit 30 that holds a plating solution Q and stores the substrate W and the anode 10 in the plating solution Q with a resistor R interposed therebetween, and between the substrate W and the anode 10. A power source 20 connected to the substrate, a substrate holder 50 for holding the substrate W and bringing the plating surface W1 of the substrate W into contact with the plating solution Q, and a plating solution Q held in the plating unit 30 for the anode 10 A resistor holder 60 having an opening 61 for holding the resistor R at the center, and the resistor in the electric path between the anode 10 and the substrate W. Plating that circulates the plating solution Q in a substrate region A1 defined by a seal (insulation seal) 170 that blocks an electrical path that does not pass through R, and the resistor R and the resistor holder 60 in the plating unit 30 The plating solution circulation system 260 that circulates the plating solution Q in the circulation system 250 and the anode region A2, and the plating solution Q is injected into the gap S1 between the substrate W and the resistor R, and the plating solution Q is injected into the gap S1. A plating solution distribution mechanism 180 having a plurality of plating solution injection ports 183 to be distributed; a plating solution Q that houses the plating unit 30 and overflows from the anode region A2; and a plating solution Q that overflows from the substrate region A1 An overflow tank 40 including a partition member 220 (see FIG. 2), a clamper 240 for attaching the substrate holder 50 to the resistor holder 60, a plating solution Q in the substrate region A1, and an anode region A2. Temperature control means 270 and 280 for maintaining the plating solution Q at a predetermined temperature are provided. The plating unit 30 and the entire overflow tank 40 are referred to as a plating tank 5. Hereinafter, each component will be described in detail.

  The substrate holder 50 exposes and holds the plated surface W1 of the substrate W in a state where the outer peripheral portion and the back surface (the surface opposite to the plated surface W1) of the substrate W are hermetically sealed, and this plated surface W1. Only a contact is made with the plating solution Q in the plating unit 30. A peripheral portion of the substrate holder 50 that holds the substrate W is a contact portion 51 that protrudes toward the resistor holder 60 side.

  In this embodiment, the resistor R is a substantially disk-shaped ceramic porous body. Specifically, the resistor R is a porous structure having a porosity of 30% or less. It is composed of one of silicon, alumina, or plastic, or a combination thereof.

  FIG. 3 is a schematic view of the resistor holder 60 as viewed from the substrate W side. As shown in FIG. 1 and FIG. 1, the resistor holder 60 is made of an insulating member, and is provided with a circular opening 61 having an outer shape and shape that accommodates and holds the resistor R just at the center. As shown in FIG. 2, the resistor holder 60 is installed so as to block the plating solution Q held in the plating unit 30 from the anode 10 side and the substrate W side. Are divided into a substrate region A1 and an anode region A2. A gap between the outer circumference of the resistor R and the inner circumference of the opening 61 of the resistor holder 60 is sealed by a seal 170 made of an insulating material so that current does not leak from the gap. Around the opening 61 of the resistor holder 60, a plurality of plating solution injection pipes 181 are attached, and their tips are plating solution injection ports 183 (183A, 183B). A plating solution circulation mechanism 180 is constituted by the plating solution injection pipe 181, the plating solution injection port 183, and the switching mechanism 190 described below. Each plating solution injection port 183 (183A, 183B) is opened around the opening 61 of the resistor holder 60 at substantially equal intervals. Each of these plating solution injection ports 183 is formed on the surface W1 to be plated of the substrate W on which the plating solution Q injected from each of the plating solution injection ports 183 is held by the substrate holder 50, as indicated by solid and dotted arrows in FIG. It is configured to flow toward the center. Further, the respective branch pipes 251A and 251B branched by the switching mechanism 190 shown in FIG. 1 are connected to the respective right plating liquid injection holes 183A and the left plating liquid injection holes 183B shown in FIG. As shown in FIG. 3, the peripheral surface of the resistor R facing the substrate W side of the resistor holder 60 is formed from the substrate holder 50 and the resistor holder 60 by contacting the contact portion 51 of the substrate holder 50. The contact surface 63 that makes the gap (space) S <b> 1 to be in a sealed state (closed space) or a state close thereto is provided, and the contact surface 63 extends from the inner periphery of the opening 61 to the outer periphery of the resistor holder 60. Four grooved plating solution discharge parts 210 are provided in the upper, lower, left and right directions.

  FIG. 4 is a schematic front view of the clamper 240. As shown in the figure, the clamper 240 is pivotally attached to both the left and right sides of the lower surface of the resistor holder 60 facing the substrate W side by pivot support portions 243, and the surface of the resistor holder 60 facing the substrate W side. A pair of clamper holding portions 245 are provided on the left and right sides of the upper portion of the upper portion. When the upper portion of the clamper 240 is held by the clamper holding portion 245, the back surface of the substrate holder 50 is pressed and supported as shown in FIG. 1, and the contact surface 63 of the resistor holder 60 is made to contact the contact portion of the substrate holder 50. The substrate holder 50 is integrally attached to the resistor holder 60 by abutting (pressure contact) 51. When the substrate holder 50 is attached to or detached from the resistor holder 60, the clamper 240 is rotated left and right to the position indicated by the dotted line in FIG. In the lower center of the resistor holder 60, when the substrate holder 50 is attached to the resistor holder 60, the lower side portion of the substrate holder 50 is brought into contact with the resistor holder 60 so as to align the substrate holder 50 in the vertical direction. A stopper 247 is installed.

  The plating solution circulation system 250 is pumped into a plating solution circulation pipe 251 connecting the bottom of the overflow tank 40 on the overflow side from the plating unit 30 on the substrate area A1 side and each plating solution injection pipe 181 of the resistor holder 60. 110, a filter 130, and a flow meter 150 are attached, and a switching mechanism 190 is further attached. The switching mechanism 190 branches the plating solution circulation pipe 251 into two branch pipes 251A and 251B. One branch pipe 251A is connected to each of the plating solution injection ports 183A, and the other branch pipe 251B is connected to each of the plating pipes. Each is connected to the liquid injection port 183B.

  The plating solution circulation system 260 includes a pump 120 in a plating solution circulation pipe 261 that connects between the bottom of the overflow tank 40 overflowing from the plating unit 30 on the anode region A2 side and the bottom of the plating layer 30 on the anode region A2 side. The filter 140 and the flow meter 160 are attached.

  The temperature control means 270 draws the pipe 271 from the overflow tank 40 on the overflow side from the plating unit 30 on the substrate area A1 side, connects the pump 90 and the temperature adjustment unit 70 into the pipe 271, and returns to the overflow tank 40 again. Configured to connect.

  The temperature control means 280 draws the pipe 281 from the overflow tank 40 on the overflow side from the plating unit 30 on the anode region A2 side, connects the pump 100 and the temperature adjustment unit 80 into this pipe 281, and again enters the overflow tank 40. Configured to connect.

  Next, a method for plating the substrate W by the plating apparatus 1-1 will be described. First, the substrate holder 50 holding the substrate W and the resistor holder 60 holding the resistor R are integrated by the clamper 240. At this time, as described above, the contact portion 51 of the substrate holder 50 contacts the contact surface 63 of the resistor holder 60, so that the periphery of the gap S1 formed between the substrate holder 50 and the resistor holder 60 is covered. This gap S1 is in a sealed state or a state close thereto. The gap S1 communicates with the outside through the plating solution discharge part 210 (see FIG. 3).

  Then, the integrated substrate holder 50 and resistor holder 60 and the anode 10 are immersed in the plating solution Q in the plating unit 30. Then, by driving the pump 110 of the plating solution circulation system 250, the plating solution injection port 183A connected to the plating solution Q in the overflow tank 40 on the substrate region A1 side via the branch pipe 251A or the branch pipe 251B, or The plating solution injection port 183B is injected into the gap S1 close to the sealed state between the substrate W and the resistor R, and the plating solution Q in the gap S1 is uniformly distributed and stirred uniformly, and then provided in the resistor holder 60. The plating solution discharge unit 210 (see FIG. 3) discharges the plating unit 30 to overflow the plating unit 30, and the overflowed plating solution Q is circulated by the pump 110 again. Similarly, by driving the pump 120 of the plating solution circulation system 260, the plating solution Q in the overflow tank 40 on the anode region A2 side is introduced into the anode region A2 of the plating unit 30 to overflow the plating unit 30 and overflow. The plating solution Q is circulated by the pump 120 again. At the same time, by driving the pump 90 of the temperature control means 270 and the pump 100 of the temperature control means 280, the temperature of the plating solution Q on the substrate region A1 side and the plating solution Q on the anode region A2 side is set to a predetermined temperature (management temperature). (Within range). In this embodiment, both temperatures are the same. In this state, when a current is passed through the plating solution Q between the substrate W and the anode 10 by the power supply 20, a desired plating film is formed on the surface W1 to be plated of the substrate W.

  By the way, in this embodiment, the switching mechanism 190 is first switched to the branch pipe 251A as a method of uniformly circulating and stirring the plating solution Q in the gap S1 close to the sealed state between the substrate holder 50 and the resistor holder 60. As shown by the solid line arrows in FIG. 3, the plating solution Q is ejected from the plating solution ejection port 183A on the right half and is ejected from the plating solution ejection unit 210, and the switching mechanism 190 is switched to the branch pipe 251B after a predetermined time has elapsed. Then, as indicated by the dotted arrow, the plating solution Q is ejected from the plating solution ejection port 183B on the left half, and is ejected from the plating solution ejection part 210, and this operation is repeated.

  Various methods can be considered as a method of spraying / discharging the plating solution Q ejected from the plating solution ejection port 183. For example, as shown by a solid arrow in FIG. 5A, when the plating solution Q is ejected from one plating solution ejection port 183A, the plating solution Q is discharged from the other plating solution ejection port 183B and is represented by a dotted arrow. When the plating solution Q is jetted from the other plating solution jet port 183B, the plating solution Q may be discharged from the one plating solution jet port 183A. In this case, the plating solution discharge part 210 is unnecessary. Further, as shown in FIG. 5B, one or a plurality of plating solution injection holes 183A and 183B may be alternately arranged. Similarly to the case described with reference to FIG. 3, when the plating solution Q is injected from one plating solution injection port 183A, as shown by the solid line arrow in FIG. 6A, the other plating solution injection port 183B. When the plating solution Q is ejected from the other plating solution injection port 183B as shown by the dotted line arrow, the injection of the plating solution Q from the plating solution discharge unit 210 is stopped and discharged from the one plating solution injection port 183A. The injection of the plating solution Q may be stopped and discharged from the plating solution discharge unit 210. Also in this case, as shown in FIG. 6B, one or a plurality of plating solution injection ports 183A and 183B may be alternately arranged. Further, as shown in FIG. 7A, the plating solution injection port 183 is divided into three or more sets (four sets in this example) (183A, 183B, 183C, 183D), and each of these plating solution injection ports 183A, B, C, and D may be switched in order and the plating solution Q may be sprayed in order.

And if the said this embodiment is used, the uniformity of the film thickness of the plating film formed in the to-be-plated surface W1 and the uniformity of the plating surface will improve more compared with the past. The reason is described below.
[Resistor R and stirring]
That is, first, in the plating apparatus 1-1, the resistor R is arranged between the anode 10 and the substrate W. As described with reference to FIGS. The current rectifying effect is higher than that of the adjustment plate 320 made of a dielectric shown in FIG. For this reason, in the method using the adjusting plate 320, the plating film thickness can be made uniform as compared with the case where the plating film thickness near the contact point between the substrate and the cathode (near the outer periphery of the substrate) is increased. In addition, in order to improve the effect (current density uniformity on the substrate W) due to the resistor R, it is necessary to narrow the distance between the resistor R and the surface W1 to be plated of the substrate W (less than 6 mm).

  On the other hand, for example, in bump plating, in order to improve the in-plane uniformity of the bump height and the uniformity of the bump surface, the plating solution Q in contact with the surface to be plated W1 of the substrate W must be stirred. However, when the resistor R is used, the distance between the resistor R and the substrate W becomes as narrow as less than about 6 mm as described above. Therefore, the adjustment plate 320 and the substrate as in the conventional dip plating apparatus 300 shown in FIG. It becomes difficult to install a paddle for stirring the plating solution Q between W. Therefore, in the present embodiment, a plurality of plating solution injection ports 183 for injecting the plating solution Q from the outer peripheral side into the gap S1 between the substrate W and the resistor R to flow the plating solution Q in the gap S1 are provided. A plating solution distribution mechanism 180 was installed. This makes it possible to distribute the plating solution Q in a uniform and random flow between the resistor R and the substrate W, and even with the plating solution Q in the narrow gap S1, it can be reliably stirred. The uniformity of the plating film thickness and the uniformity of the plating surface can be achieved.

  For example, when the plating solution Q is caused to flow through a narrow gap of about 300 mm in diameter and less than 6 mm in width, a place where the plating solution Q is easy to flow and a place where it is difficult to flow are likely to be generated due to flow path resistance. Stagnation and difficult to distribute uniformly. Therefore, in the present embodiment, by spraying the plating solution Q in the direction from the outer periphery of the surface W1 of the substrate W held by the substrate holder 50 toward the center, the substrate W The plating solution Q is surely poured into the narrow gap S1 between the resistors R, and the plating solution Q is circulated over the entire surface of the substrate W.

  Further, the shape of the bump surface is easily affected by the flow of the plating solution Q. If the flow of the plating solution Q is in a certain direction, the shape of the bump surface may be non-uniform. Need to give flow. Therefore, in the above embodiment, the plating solution injection port 183 for injecting the plating solution Q is changed and changed at a predetermined timing in order to give a random flow, thereby causing the plating solution Q to flow at random, and thereby the bump height. In-plane uniformity and bump surface uniformity are improved. In order to ensure that the plating solution Q supplied from the plating solution injection port 183 does not go around the resistor R and passes through the gap S1 between the substrate W and the resistor R, the substrate holder 50 and the resistor holder The gap formed from 60 is in a sealed state or a state close thereto.

[Interruption of electrical paths other than resistor R]
In order to make the current density of the surface W1 to be plated of the substrate W uniform, current leakage to the current path other than the resistor R must be blocked. For this purpose, the plating solution Q on the anode 10 side (anode region A2) and the plating solution Q on the cathode side (substrate region A1) must be insulated. Therefore, in this embodiment, the plating unit 30 is divided into the substrate region A1 and the anode region A2 by the resistor holder 60, and the partition member 220 is installed in the overflow tank 40 so that the overflowed plating solutions Q do not touch each other. . In order to prevent current leakage from the gap between the resistor R and the resistor holder 60, a seal 170 is provided on the outer periphery of the resistor R.

[Attaching the substrate holder 50 by the clamper 240]
In order to obtain a good plating film thickness uniformity, it is necessary that the center of the resistor R and the center of the surface W1 of the substrate W coincide with each other. Accordingly, when the substrate holder 50 is attached to the resistor holder 60, it is necessary to always attach the substrate holders 50 so that their centers do not deviate from each other, and the substrate holder 50 needs to be easily attached and detached. Therefore, in the above-described embodiment, by attaching the clamper 240 to the resistor holder 60 and securely fixing the substrate holder 50 to the resistor holder 60 using the clamper 240, the substrate holder 50 can be easily attached and detached and the resistor R And the alignment of the substrate W. The positional relationship between the resistor R and the substrate W can be always adjusted to the same position by placing the lower end of the substrate holder 50 on the stopper 247 as described above. Can be always adjusted to the same position. Thus, the center of the resistor R and the substrate W can be easily aligned by aligning the vertical and horizontal positions.

  Further, in order to surely flow the plating solution Q into the gap S1 between the resistor R and the substrate W and uniformly stir the plating solution Q in the gap S1 uniformly, the gap S1 between the resistor R and the substrate W is sealed. Alternatively, it is necessary to be in a state close to sealing, but by pressing the substrate holder 50 with the clamper 240 attached to the resistor holder 60, the resistor holder 60 and the substrate holder 50 can be easily brought into close contact with each other. The gap S1 between the resistor R and the substrate W can be easily sealed or nearly sealed.

  In addition, the plating apparatus 1-1 concerning this invention can respond to the board | substrate diameter increase in the future. That is, when the diameter of the substrate W becomes 400 mm or the like in the future, the distance from the center to the outer periphery of the substrate W becomes longer, thereby further increasing the influence of the terminal effect, and the adjustment plate made of the current dielectric. Then, it becomes increasingly difficult to prevent the outer peripheral portion of the substrate from becoming thicker. By using the resistor R instead of the conventional adjusting plate, the current density on the substrate W is made uniform, and the in-plane uniformity of the bumps is also improved. Thus, by applying the resistor R to the bump plating apparatus 1-1 of the dip method and adding various devices as in the above embodiment, it is possible to cope with future increase in the substrate diameter.

  In the plating apparatus 1-1 shown in FIG. 1, a ceramic porous body (pore diameter 10 to 20 μm, porosity 30%) is used for the resistor R, and the plating solution Q is copper sulfate, sulfuric acid, chlorine and additives. It adjusted using. The substrate W used was a semiconductor wafer having a diameter of 200 mm, a Cu seed layer thickness of 600 nm, and a resist pattern hole diameter and depth of 150 μm and 120 μm, respectively. As shown in FIG. 1, each member such as the anode 10, the resistor R, and the substrate W was set. The distance between the substrate W and the resistor R was 5.5 mm. Then, as described with reference to FIG. 3, the plating solution Q is alternately sprayed from the two sets of plating solution injection ports 183A and 183B between the substrate W and the resistor R, and the plating solution Q overflowed from the plating unit 30 is pumped 110. And it was made to circulate through the filter 130 again to the plating solution injection ports 183A and 183B. The plating solution Q on the anode 10 side was also circulated through the pump 120 and the filter 140. Further, the temperature of the plating solution Q on the substrate W side was maintained at 23 ° C. by the temperature adjustment unit 70, and the temperature of the plating solution Q on the anode side was maintained at 23 ° C. by the temperature adjustment unit 80. In this state, when plating was performed by supplying a current so that the height of copper (bump) to be plated in the hole on the substrate surface was 100 μm, the height in the substrate surface as shown in FIG. A uniform bump was obtained.

(Comparative Example 1)
FIG. 9 shows an overall schematic configuration diagram of a plating apparatus 500 according to a comparative example. The plating apparatus 500 is different from the plating apparatus 1-1 only in that a porous plate 230 is installed instead of the resistor R. Other configurations are the same as those of the plating apparatus 1-1. FIG. 10 is a view showing the perforated plate 230, FIG. 10 (a) is a plan view, and FIG. 10 (b) is a side view. As shown in the figure, the perforated plate 230 has a disc shape, is installed between the anode 10 and the substrate W, and has a plurality of circular through holes 231 (inner diameter 2 mm) distributed evenly in a circular region. Yes. The configuration of the plating solution Q and the substrate W and the separation distance between the substrate W and the porous plate 230 are the same as those in the first embodiment. Then, when plating was performed by supplying the current so that the height of the copper (bump) to be plated in the hole on the surface of the substrate was 100 μm by the same method as in Example 1, FIG. ), The height of the bump was higher in the outer peripheral portion than in the central portion of the substrate.

  Using the plating apparatus 1-1 having the same configuration as that of Example 1, the spraying state of the liquid Q from the plating solution injection port 183 was varied. That is, as in Example 1, a ceramic porous body (pore diameter 10 to 20 μm, porosity 30%) was used as the resistor R, and the plating solution Q was adjusted using copper sulfate, sulfuric acid, chlorine and additives. did. The substrate W used was a semiconductor wafer having a diameter of 200 mm, a Cu seed layer thickness of 600 nm, and a resist pattern hole diameter and depth of 150 μm and 120 μm, respectively. As shown in FIG. 1, each member such as the anode 10, the resistor R, and the substrate W was set. The distance between the substrate W and the resistor R was 5.5 mm. As shown in FIGS. 5 to 7 and 11, the plating solution Q is injected between the substrate W and the resistor R from the plating solution injection port 183 at a flow rate of 3 L / min, and overflows from the plating unit 30. Was circulated to the plating solution injection port 183 through the pump 110 and the filter 130. The plating solution Q on the anode 10 side was also circulated through the pump 120 and the filter 140. Further, the temperature of the plating solution Q on the substrate W side was kept at 23 ° C. by the temperature adjustment unit 70, and the temperature of the plating solution Q on the anode 10 side was kept at 23 ° C.

  Then, the plating solution Q is agitated by the following injection / discharge methods (1) to (4), and the current is applied so that the height of the copper (bump) plated in the hole on the substrate surface in each case becomes 100 μm. The plating was carried out and the results were examined.

[Injection / Discharge Method 1] Using the above-described injection / discharge method of the plating solution Q shown in FIGS. 5A and 5B, the plating solution Q is injected from the plating solution injection port 183A and simultaneously from the plating solution injection port B. The plating solution Q was discharged, and after 5 seconds, the plating solution injection ports 183A and 183B were switched in reverse to reverse the injection and discharge, thereby reversing the flow of the plating solution Q. This was repeated to give a random flow to the plating solution Q and stirred.

[Injection / Discharge Method 2] Using the above-described injection / discharge method of the plating solution Q shown in FIGS. 6A and 6B, the plating solution Q is injected from the plating solution injection port 183A for 5 seconds, and then the plating solution is injected. Switching to the port 183B, the plating solution Q was sprayed for 5 seconds, and the flow of the plating solution Q was reversed. This was repeated to give a random flow to the plating solution Q and stirred.

[Injection / Discharge Method 3] Using the plating solution Q injection / discharge method shown in FIG. 7, the plating solution injection ports 183A to 183D were switched every 2 seconds to change the flow of the plating solution Q. This was repeated to give a random flow to the plating solution Q and stirred.

[Injection / Discharge Method 4] Using the injection / discharge method shown in FIG. 11, during the plating, the plating solution Q was continuously injected only from the plating solution injection port 183A, and the flow of the plating solution Q was set to one direction. The sprayed plating solution Q was discharged from the discharge port 210.

  The state of the copper (bump) in the hole on the surface of the substrate plated by the above jetting / discharging methods 1 to 4 is as shown in FIG. Although uniform, the injection / discharge method 4 was non-uniform under the influence of the flow of the plating solution as shown in FIG.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. Note that any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited. For example, in the above embodiment, the plating solution injection port 183 is disposed around the opening 61 of the resistor holder 60. However, for example, like the plating apparatus 1-2 illustrated in FIG. You may arrange. FIG. 14 is a schematic view of the substrate holder 50 of the plating apparatus 1-2 as viewed from the resistor R side. In the plating apparatus 1-2 shown in FIG. 13, the same or equivalent parts as those in the plating apparatus 1-1 shown in FIG. Note that matters other than those described below are the same as those of the plating apparatus 1-1. That is, in this plating apparatus 1-2, a plurality of plating solution injections are performed so that the plating solution injection ports 183 (183A, 183B) are positioned around the substrate W on the side of the substrate holder 50 that holds the substrate W. A tube 181 is attached. Also in this embodiment, the plating solution distribution mechanism 180 is configured by the plating solution injection pipe 181, the plating solution injection port 183, and the switching mechanism 190. In addition, also when arrange | positioning the plating solution distribution | circulation mechanism 180 at the board | substrate holder 50 side like this embodiment, the various injection | emission / discharge methods as shown to the said FIGS. 5-7 are applicable.

  Various spraying states can be considered as the spraying state of the plating solution Q sprayed from the plating solution spraying port 183. For example, as shown in FIG. 15A, the plating solution Q sprayed from the plating solution spraying port 183. May be configured to flow linearly toward the center of the surface to be plated W1 of the substrate W, or fan-shaped toward the center of the surface to be plated W1 of the substrate W as shown in FIG. You may comprise so that it may spread and flow. The difference in the flow of the plating solution Q can be realized by the shape of the concave groove 185 formed around the plating solution injection port 183. Moreover, in the said embodiment, although the clamper 240 was attached to the resistor holder 60, you may attach to the board | substrate holder 50 side instead.

It is the whole schematic block diagram of the plating apparatus 1-1. It is the schematic plan view which looked at the anode 10, the plating unit 30, the overflow tank 40, the board | substrate holder 50, and the resistor holder 60 of the plating apparatus 1-1 from the upper direction. It is the schematic which looked at the resistor R and the resistor holder 60 from the board | substrate W side. 3 is a schematic front view of a clamper 240. FIG. FIG. 5A and FIG. 5B are schematic views showing the resistor holder 60, and FIG. 5C is a view of each of the plating solution injection ports 183A and 183B. It is a figure which shows injection timing. FIG. 6A and FIG. 6B are schematic views showing a resistor holder 60, and FIG. 6C is a view of each of the plating solution injection ports 183A and 183B. It is a figure which shows injection timing. FIGS. 7A and 7B are diagrams illustrating a method of spraying and discharging the plating solution Q, FIG. 7A is a schematic diagram illustrating the resistor holder 60, and FIG. 7B is a diagram illustrating spray timings of the plating solution spray ports 183A and 183B. is there. FIG. 4 is a diagram illustrating a bump height distribution on a substrate W. 1 is an overall schematic configuration diagram of a plating apparatus 500. FIG. FIG. 7A is a plan view and FIG. 7B is a side view showing a porous plate 230. It is a figure which shows the injection / discharge method of the plating solution Q. It is a figure which shows bump cross section. It is a whole schematic block diagram of the plating apparatus 1-2. It is the schematic of the substrate holder 50 of the plating apparatus 1-2. It is a figure which shows the injection state of the plating solution injected from the plating solution injection port. 1 is a schematic configuration diagram showing an electroplating apparatus 300. FIG. It is a figure which shows the equivalent circuit of typical electrolytic plating. It is a figure which shows the equivalent circuit of the electroplating which inserted the high resistance structure.

Explanation of symbols

1-1 Plating apparatus Q Plating solution W Substrate W1 Surface to be plated R Resistor A1 Substrate region A2 Anode region S1 Gap 5 Plating tank 10 Anode 20 Power supply 30 Plating unit 40 Overflow tank 50 Substrate holder 60 Resistor holder 61 Opening 70 Temperature Adjustment unit 80 Temperature adjustment unit 170 Seal 180 Plating solution distribution mechanism 181 Plating solution injection pipe 183 (183A, 183B, 183C, 183D) Plating solution injection port 190 Switching mechanism 210 Plating solution discharge part (plating solution discharge port)
220 Partition member (partition plate)
240 Clamper 247 Stopper 250 Plating solution circulation system 260 Plating solution circulation system 270 Temperature control means 280 Temperature control means

Claims (11)

A plating unit for holding a plating solution, storing a substrate, a resistor, and an anode in this order in this order and energizing between the substrate and the anode to plate the surface to be plated, and this plating unit A plating tank having an overflow tank for storing the inside,
A substrate holder for holding the substrate and bringing the plating surface of the substrate into contact with the plating solution;
A resistor holder that is installed to block the plating solution held in the plating unit on the anode side and the substrate side, and has an opening for holding the resistor;
A seal that blocks an electrical path that does not pass through the resistor among electrical paths between the anode and the substrate;
A plating solution distribution mechanism having a plurality of plating solution injection ports for injecting a plating solution into a gap between the substrate and the resistor and distributing the plating solution in the gap;
A plating solution circulation system for circulating a plating solution in each of an anode region and a substrate region defined by a resistor and a resistor holder in the plating unit, and
Furthermore, the plating apparatus characterized by providing the said overflow tank with the partition member which interrupts | blocks the plating solution which overflows from the said anode area | region, and the plating solution which overflows from a board | substrate area | region.   The plating solution distribution mechanism distributes the plating solution into the gap by spraying the plating solution into the gap between the substrate and the resistor through the plating solution injection port and discharging the plating solution filled in the gap. The plating apparatus according to claim 1, wherein the plating apparatus is configured to perform the above-described configuration.   3. The plating apparatus according to claim 1, wherein the plurality of plating solution ejection ports are arranged around an opening of the resistor holder or along an outer peripheral portion of the substrate.   The plating solution spray port is configured such that the plating solution sprayed from the plating solution spray port flows linearly or in a fan shape toward the center of the plated surface of the substrate held by the substrate holder. The plating apparatus according to any one of claims 1 to 3, wherein:   5. The plating solution distribution mechanism according to claim 1, further comprising a switching mechanism for switching the plurality of plating solution injection ports to inject the plating solution from all or a part of the plurality of plating solution injection ports. The plating apparatus in any one of.   6. The plating apparatus according to claim 1, wherein the substrate holder is attached in close contact with the resistor holder by a clamper. While placing the plating surface of the substrate held in the substrate holder in contact with the plating solution in the plating unit,
The anode is immersed in a plating solution in the plating unit so as to face the surface to be plated of the substrate, and is arranged.
A resistor holder having an opening and holding a resistor in the opening is arranged between the substrate and the anode so as to block the plating solution in the plating unit,
Further, a plurality of plating solution injection ports for injecting and distributing the plating solution into the gap between the substrate and the resistor are arranged,
A plating current is injected between the anode and the substrate while discharging the plating solution filled in the gap from the plating solution injection port toward the center of the surface to be plated of the substrate. The plating method is characterized in that the surface to be plated is plated by energizing the substrate.   The plating method according to claim 7, wherein the plurality of plating solution injection ports are arranged around an opening of the resistor holder or along an outer peripheral portion of the substrate.   The plating solution according to claim 7 or 8, wherein the plating solution injected from the plating solution injection port is caused to flow linearly or in a fan shape toward the center of the surface to be plated of the substrate held by the substrate holder. Method.   The plating solution is sprayed from all or a part of the plurality of plating solution injection ports by switching the plurality of plating solution injection ports for injecting the plating solution. The plating method described in 1.   The plating method according to claim 7, wherein the substrate holder is attached to the resistor holder in close contact with a clamper.

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