Patent Application
20250116024
The present invention relates to plating apparatuses.
For formation of an external electrode of an electronic component, what is called a jet flow-type plating apparatus is widely used. Japanese Patent Laid-Open No. 2021-138999 discloses a jet flow-type plating apparatus.
The plating apparatus disclosed in Japanese Patent Laid-Open No. 2021-138999 includes a plating bath. A metal pipe (a cathode) defining and functioning as the first electrode, a partition wall pipe made of an insulating material, and the second electrode (an anode) are accommodated in the plating bath. The partition wall pipe is provided with a plurality of small holes through which a plating solution passes but through which plating targets, media and the like do not pass.
A metal pipe is disposed inside the partition wall pipe, and a plating forming portion is formed between the inside of the partition wall pipe and the outside of the metal pipe. The plating forming portion is a region (a space) in which plating is performed on a plating target which is an object to be plated. The second electrode is disposed outside the partition wall pipe.
An injection unit having an injection port for injecting the plating solution is provided below the metal pipe. The injection unit serves to generate an upward flow of the plating solution inside the metal pipe. Although not disclosed in the plating apparatus of Japanese Patent Laid-Open No. 2021-138999, a mesh member is typically provided at the injection port of the injection unit to prevent the plating targets and the media from falling into the injection unit when the injection is stopped.
In the plating apparatus disclosed in Japanese Patent Laid-Open No. 2021-138999, a plating solution is accommodated in the plating bath. Then, plating targets, electrically conductive media, and, if required, insulating balls are introduced into the plating bath accommodating the plating solution. Note that the plating solution may be accommodated in the plating bath after the plating targets, the media, and the insulating balls have been introduced into the plating bath. While the plating targets each are plated in the plating forming portion, the media serve to establish an electrical connection between the metal pipe defining and functioning as the first electrode and a plated area (a region in which a base electrode and the like are formed) on the surface of each plating target. The insulating balls serve to enhance the fluidity of each plating target circulating through the plating apparatus.
The plating targets, the media, and the insulating balls are moved upward through the metal pipe with the upward flow of the plating solution inside the metal pipe, the upward flow being generated by the injection from the injection unit, then jetted to the outside from an upper end of the metal pipe, and stirred in the plating solution.
The plating targets, the media, and the insulating balls that have been stirred are then deposited on the upper side of the plating forming portion. At this time, other plating targets, media, and insulating balls have already been deposited in the plating forming portion. The plating targets, the media, and the insulating balls deposited on the upper side of the plating forming portion gradually fall downward through the plating forming portion. At this time, a current is applied between the metal pipe defining and functioning as the first electrode and the second electrode to form a plated film on the plated area on the surface of each plating target.
The plating targets each having the plated film formed thereon, the media, and the insulating balls are extruded from a lower end of the plating forming portion, and again moved upward through the metal pipe with the upward flow of the plating solution, the upward flow being generated inside the metal pipe, then jetted to the outside from the upper end of the metal pipe, and stirred. As before, the plating targets, the media, and the insulating balls that have been stirred are then deposited on the upper side of the plating forming portion, then gradually fall downward through the plating forming portion, and a plated film is formed on each plating target during the falling.
The plating targets may circulate several times to several thousand times through the plating apparatus until the plated films each have a predetermined thickness and the plating step ends.
Plating on plating targets should satisfy the following (a) and (b):
When the amount of time from the start of plating to the end of plating in one plating step (one lot) is defined as a “total plating time,” and given that the total plating time is constant, the thicknesses of a plated film formed on each plating target is substantially the same even when the time required for a single pass of each plating target through the plating forming portion and the number of times each plating target passes through the plating forming portion are varied. This is because the thickness of the plated film formed on each plating target depends on the total time in which each plating target passes through the plating forming portion (the time required for a single pass through the plating forming portion×the number of passes). Naturally, when the total plating time is constant, increasing the time required for a single pass of each plating target through the plating forming portion results in a reduced number of times each plating target passes through the plating forming portion, and reducing the time required for a single pass of each plating target through the plating forming portion results in an increased number of times each plating target passes through the plating forming portion.
On the other hand, when the total plating time is constant, the thickness variation in the formed plated film is smaller among a plurality of plating targets when the time required for a single pass of each plating target through the plating forming portion is reduced and the number of times each plating target circulates through the plating apparatus is increased, than when the time required for a single pass of each plating target through the plating forming portion is increased and the number of times each plating target circulates through the plating apparatus is reduced. In other words, since the thickness of the plated film formed (grown) on each plating target with each pass of the plating target through the plating forming portion depends on such conditions as whether the plating target passes close to the metal pipe, passes close to the partition wall pipe, or passes close to halfway between the metal pipe and the partition wall pipe, the thickness variation in the formed plated film can be reduced by increasing and leveling out the number of passes.
Considering the productivity of the plating step, it is preferable that the total plating time is short. In the limited total plating time, a flow rate of the plating solution injected from the injector may be increased in order to increase the number of times each plating target passes through the plating forming portion, and an output of a pump connected to the injector may be increased, for example, in order to increase the flow rate of the plating solution injected from the injector.
However, when the flow rate of the plating solution injected from the injector is increased, defects may occur in the plating targets, such as “cracking” or “chipping” of the plating targets, or “peeling” of the plated films formed on the plating targets. This may be because, when the flow rate of the plating solution injected from the injector is increased, the plating targets are moved upward with too much speed through the metal pipe defining and functioning as the first electrode, and the plating targets jetted to the outside from the upper end of the metal pipe are moved upward to a high position in the plating solution stored in the plating bath and collide with a reflection plate which is called a deflector, or collide with an inner wall of the plating bath or other plating targets when falling downward (settling) from the high position in the plating solution. In other words, the plating targets are discharged along with the media and the insulating balls to the outside from the upper end of the metal pipe in order to stir them. At this time, however, if the plating targets are moved upward with too much momentum to a high position in the stored plating solution, defects may occur in the plating targets.
Therefore, example embodiments of the present invention provide a plating apparatus by which plating targets are not moved upward excessively to a high position in a stored plating solution, and the occurrence of defects in the plating targets is reduced or prevented, even when a flow rate of the plating solution injected from an injector is increased.
Plating apparatuses according to example embodiments of the present invention are each able to solve the above-described conventional problems.
A plating apparatus according to an example embodiment of the present invention includes a plating bath in which a plating solution including plating targets is stored, and an injector provided in the plating bath, the injector including a first injection port to inject the plating solution. The plating targets included in the plating solution are stirred by the plating solution injected from the injector. A mesh portion is provided at the first injection port of the injector. The mesh portion is made by stacking at least two meshes. The mesh portion includes a central portion and a circumferential portion provided outside the central portion when viewed in a planar direction. The circumferential portion is defined by one layer of the mesh or a plurality of layers of the mesh. The central portion is made of a plurality of layers of the mesh. A number of layers of the mesh in the central portion is greater than a number of layers of the mesh in the circumferential portion.
In the above-described plating apparatus according to an example embodiment of the present invention, the plating targets are not moved upward excessively to a high position in the stored plating solution, and the occurrence of defects in the plating targets is reduced or prevented, even when a flow rate of the plating solution injected from the injector is increased. A supplemental explanation is provided below.
The speed of the plating solution that passes (that is moved upward) through the metal pipe defining and functioning as the first electrode is not uniform across the cross section of the metal pipe, but increases toward a central portion of the metal pipe and decreases toward a circumferential portion close to an inner wall of the metal pipe. This is because resistance is generated to a flow of the plating solution in the circumferential portion close to the inner wall of the metal pipe, which reduces or prevents the speed of the plating solution.
In addition, when the: injector having an inner cylindrical shape is provided on a bottom surface of the plating bath of the plating apparatus, the first injection port is provided on the upper side of the injector, a second injection port that injects the plating solution into the injector is provided in the bottom surface of the injector, and the diameter of the second injection port is smaller than the inner diameter of the metal pipe, the speed of the plating solution may also increase toward the central portion of the metal pipe and decrease toward the circumferential portion close to the inner wall of the metal pipe.
On the other hand, when the flow rate of the plating solution injected from the injector is increased, not all of the plating targets jetted to the outside from the upper end of the metal pipe are moved upward to a high position in the plating solution stored in the plating bath. The plating targets that are moved upward to a high position in the plating solution stored in the plating bath are considered to be mainly plating targets that have passed (that have been moved upward) all at once through the central portion of the metal pipe where the speed of the plating solution is high.
In plating apparatuses according to example embodiments of the present invention, the speed of the plating solution that passes (that is moved upward) through the metal pipe is reduced or prevented in the central portion of the metal pipe. Thus, the plating targets are not moved upward excessively to a high position in the stored plating solution, and the occurrence of defects in the plating targets is reduced or prevented, even when the flow rate of the plating solution injected from the injector is increased.
The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.
Hereinafter, example embodiments of the present invention will be described with reference to the accompanying drawings.
Each example embodiment of the present invention is not limited to contents of the specifically depicted example embodiment. Contents described in different example embodiments can also be implemented in combination, and the contents implemented in that case are also encompassed in the present invention. The accompanying drawings serve to help understanding of the specification and may schematically be drawn. A ratio of the dimensions of a drawn component or components may not be equal to a ratio of the dimensions described in the specification. Components described in the specification may be omitted in the drawings or may be drawn in reduced number.
Plating apparatus 100 includes a plating bath 1. An upper side of plating bath 1 is open. Plating bath 1 serves to accommodate a mixture 16 of a plating solution, plating targets, media, and insulating balls, which will be described later. Note that the insulating balls can be omitted if not required.
Plating apparatus 100 includes a cylindrical metal pipe 2 provided inside plating bath 1. Metal pipe 2 includes a hollow portion 2a. Metal pipe 2 defining and functioning as the first electrode is a cathode electrode in the present example embodiment. In the present example embodiment, metal pipe 2 has a cylindrical shape. Metal pipe 2 may alternatively have a polygonal cylindrical shape. Metal pipe 2 may be made of any material and can be made using various metals.
In the present example embodiment, two rod-shaped electrically-conductive support portions 2b are preferably integrally provided with metal pipe 2 at an upper portion of metal pipe 2. The number of support portions 2b is not limited to two and may be any number.
Plating apparatus 100 includes a partition wall pipe 3 made of an insulating material and provided inside plating bath 1. Partition wall pipe 3 includes a hollow portion 3a. In the present example embodiment, partition wall pipe 3 has a cylindrical shape. Partition wall pipe 3 may have a polygonal cylindrical shape. Partition wall pipe 3 is provided with a plurality of small holes 3b through which the plating solution passes but through which the plating targets, the media, and the insulating balls do not pass. When a current is applied between metal pipe 2 defining and functioning as the first electrode and a second electrode 5, holes 3b allow the current to pass through the plating solution. Partition wall pipe 3 may be made of any material and can be made, for example, using various resins.
The inner diameter of partition wall pipe 3 is larger than the outer diameter of metal pipe 2. Metal pipe 2 is located inside hollow portion 3a of partition wall pipe 3. A plating forming portion 4 is provided between the inside of partition wall pipe 3 and the outside of metal pipe 2. Plating forming portion 4 is a region (a space) in which the plating targets each are plated. In
The plating targets, the media, and the insulating balls are deposited inside plating forming portion 4 and gradually fall downward. At some point during this falling, the surface of each plating target is plated.
Plating apparatus 100 preferably includes second electrode 5 provided inside plating bath 1. In the present example embodiment, second electrode 5 is an anode electrode. In the present example embodiment, second electrode 5 is made of metal having a cylindrical shape. Second electrode 5 is disposed outside partition wall pipe 3. Second electrode 5 may be made of any material and can be made using various metals.
As shown in
Plating apparatus 100 includes an injector 6 below metal pipe 2. Injector 6 defines and functions to generate an upward flow of the plating solution inside metal pipe 2. In the present example embodiment, injector 6 has an inner cylindrical shape including a bottom surface and an inner wall. In the present example embodiment, the inner cylindrical shape of injector 6 is an inner circular cylindrical shape. The inner cylindrical shape of injector 6 is not limited to the inner circular cylindrical shape and may be other shapes.
A first injection port 6a is preferably provided in an upper end of injector 6. A second injection port 6b is preferably provided in the bottom surface of injector 6. The plating solution is injected into injector 6 from second injection port 6b. The plating solution is injected into plating bath 1 from first injection port 6a. In the present example embodiment, the opening area of second injection port 6b is smaller than the opening area of first injection port 6a.
When comparing the inner diameter of metal pipe 2 with the diameter of second injection port 6b, the diameter of second injection port 6b is smaller than the inner diameter of metal pipe 2. This also causes an increase in the speed of the plating solution in a central portion of metal pipe 2. Thus, measures have been taken to reduce or prevent the speed of the plating solution in the central portion of metal pipe 2.
A mesh portion 7 is provided at first injection port 6a of injector 6. Mesh portion 7 is provided to prevent the plating targets, the media, and the insulating balls from falling into injector 6 when the injection from injector 6 is stopped. In the present example embodiment, since first injection port 6a of injector 6 has a circular shape, mesh portion 7 also has a circular shape when viewed in the planar direction.
In the present example embodiment, mesh portion 7 is formed by stacking two meshes (e.g., network members). Mesh portion 7 may be formed by, for example, stacking at least two meshes, and may be formed by stacking three or more meshes. In the present example embodiment, mesh portion 7 is defined by a first mesh layer 7a and a second mesh layer 7b, as shown in
First mesh layer 7a and second mesh layer 7b are each made of mesh. It is preferable that first mesh layer 7a and second mesh layer 7b are electrically insulating. First mesh layer 7a and second mesh layer 7b may be made of any material and can be made, for example, using nylon. First mesh layer 7a and second mesh layer 7b can be joined together by an adhesive, for example, or can simply be overlaid on each other and secured at their edges.
As shown in
In the present example embodiment, second mesh layer 7b of central portion 7c has a circular shape, as shown in
A mesh opening of first mesh layer 7a may be the same as or different from a mesh opening of second mesh layer 7b. In the present example embodiment, a mesh having a mesh opening of, for example, about 900 μm is used for each of first mesh layer 7a and second mesh layer 7b. The “mesh opening” of a mesh means a dimension between adjacent lines (excluding the line size) in a mesh formed by vertical lines and horizontal lines intersecting each other. The mesh opening may be referred to as an opening (OP) or an opening dimension.
The mesh opening generally refers to a mesh opening of one layer of mesh, but may refer, when a plurality of meshes are stacked, to an overall mesh opening of the plurality of meshes in the application document of the present invention. When comparing the mesh opening of one layer of mesh with the mesh opening of two stacked layers of that mesh (or the mesh opening of that mesh and another mesh that are stacked on each other), the latter is smaller (finer) than the former.
In the present example embodiment, in mesh portion 7, a mesh opening of central portion 7c defined by two layers of mesh is smaller than a mesh opening of circumferential portion 7d defined by one layer of mesh when viewed in the planar direction. If the vertical lines and horizontal lines of first mesh layer 7a completely overlap the vertical lines and horizontal lines of second mesh layer 7b in central portion 7c, the mesh opening of central portion 7c will be the same as the mesh opening of circumferential portion 7d. However, that is rarely the case.
Central portion 7c of mesh portion 7 is not limited to have a double mesh structure defined by two layers of mesh. For example, central portion 7c may have a triple mesh structure defined by three layers of mesh, and circumferential portion 7d may have a single mesh structure defined by one layer of mesh. Alternatively, an intermediate portion (not shown) may be provided between central portion 7c and circumferential portion 7d, where central portion 7c has a triple mesh structure, the intermediate portion has a double mesh structure, and circumferential portion 7d has a single mesh structure. In other words, in mesh portion 7, the number of layers of mesh may be increased, particularly in a portion where the passage of the plating solution should be reduced or prevented. While a single mesh structure defined by one layer of mesh is basically sufficient for circumferential portion 7d, circumferential portion 7d may have a multiple mesh structure defined by a plurality of layers of mesh. In this manner, different variations can be adopted for the structure of mesh portion 7.
In the present example embodiment, mesh portion 7 is preferably formed by stacking first mesh layer 7a occupying the entire or substantially the entire area of mesh portion 7 and defining and functioning as the upper layer, and second mesh layer 7b occupying a portion of mesh portion 7 and defining and functioning as the lower layer, as shown in
In plating apparatus 100, the momentum of the plating solution passing through mesh portion 7 is reduced or prevented in central portion 7c having a double mesh structure. Additionally, in plating apparatus 100, the momentum of the plating solution injected from second injection port 6b is reduced or prevented by central portion 7c having a double mesh structure.
Plating apparatus 100 preferably includes a circulation line 8 defined by a pipe. Circulation line 8 preferably includes one end connected to a liquid suction port 9 provided in plating bath 1, and another end connected to second injection port 6b of injector 6. A pump 10 and a filter 11 are provided at points in circulation line 8. When pump 10 is driven, circulation line 8 suctions the plating solution from liquid suction port 9 and injects the plating solution from second injection port 6b.
Plating apparatus 100 includes a mixer 12 below metal pipe 2 and partition wall pipe 3 and above injector 6. Mixer 12 is a region in which the plating solution injected from first injection port 6a of injector 6 is mixed with the plating targets, the media, and the insulating balls that have fallen downward through plating forming portion 4. In the present example embodiment, mixer 12 is preferably made of an electrically insulating material and includes an upper surface including a recess formed in the shape of an inverted truncated cone. The inverted truncated cone means a truncated cone shaped such that an upper bottom surface is larger than a lower bottom surface. Note that the recess may have any shape and may have a bowl shape or the like in place of the shape of an inverted truncated cone.
First injection port 6a of injector 6 is located in a bottom surface of mixer 12. As described above, mesh portion 7 is provided at first injection port 6a of injector 6. By the provision of mesh portion 7 at first injection port 6a, the plating targets, the media, and the insulating balls do not fall into injector 6 when the injection from injector 6 is stopped.
Plating apparatus 100 preferably includes a guide portion 13 above metal pipe 2 and partition wall pipe 3. In guide portion 13, the plating targets, the media, and the insulating balls that have been moved upward with the upward flow of the plating solution and jetted (e.g., discharged) from an upper opening of hollow portion 2a of metal pipe 2 are stirred and subsequently guided to plating forming portion 4. In this case, the upward flow of the plating solution has been provided inside hollow portion 2a of metal pipe 2 by the injection from first injection port 6a of injector 6. Guide portion 13 is made of an insulating material and has a shape of an inverted truncated cone in the present example embodiment. Guide portion 13 includes a bottom surface through which an upper end of metal pipe 2 protrudes. An upper end of hollow portion 2a of metal pipe 2 is opened in the bottom surface of guide portion 13. The bottom surface of guide portion 13 is connected to partition wall pipe 3.
Plating apparatus 100 includes an insulative reflection plate 14 above the opening of plating bath 1. Reflection plate 14 may be referred to as a deflector. Reflection plate 14 acts to reduce or prevent scattering of the plating solution. Further, reflection plate 14 preferably includes a lower surface to which support portion 2b of metal pipe 2 is attached. A cylindrical reduce or prevention plate 14a is provided on the lower surface of reflection plate 14. Reduce or prevention plate 14a is located inside guide portion 13. While the plating solution may overflow to the outside beyond an upper edge of guide portion 13, reduce or prevention plate 14a allows only the plating solution to overflow from guide portion 13 but prevents overflowing of the plating targets, the media, and the insulating balls.
Plating apparatus 100 includes a power supply 15. Power supply 15 preferably includes one line connected to support portion 2b of metal pipe 2 defining and functioning as the first electrode, and another line connected to second electrode 5. Power supply 15 applies a current between metal pipe 2 defining and functioning as the first electrode and second electrode 5.
In plating apparatus 100 having the above-described structure according to the first example embodiment, the momentum of the plating solution injected from first injection port 6a of injector 6 is controlled (e.g., adjusted) by mesh portion 7. Specifically, the momentum of the plating solution injected from first injection port 6a of injector 6 and passing through mesh portion 7 is reduced or prevented in central portion 7c defined by first mesh layer 7a and second mesh layer 7b stacked on each other, as compared to in circumferential portion 7d defined by only first mesh layer 7a.
As described above, the speed of the plating solution that is moved upward through metal pipe 2 defining and functioning as the first electrode increases toward the central portion of metal pipe 2 and decreases toward the circumferential portion close to the inner wall of metal pipe 2. In addition, when the flow rate of the plating solution injected from injector 6 is increased, the plating targets that are moved upward to a high position in the plating solution stored in the plating bath among the plating targets jetted to the outside from the upper end of metal pipe 2 are considered to be mainly plating targets that have been moved upward all at once through the central portion of metal pipe 2 where the speed of the plating solution is high.
In plating apparatus 100, the momentum of the plating solution injected from first injection port 6a of injector 6 is reduced or prevented in central portion 7c defined by first mesh layer 7a and second mesh layer 7b stacked on each other, as compared to in circumferential portion 7d defined by only first mesh layer 7a, so that the momentum of the plating solution that is moved upward through the central portion of metal pipe 2 can be reduced or prevented. More specifically, in plating apparatus 100, when the amount of the plating solution injected from injector 6 is constant, the speed of the plating solution that is moved upward through the central portion of metal pipe 2 can be reduced, as compared to when a mesh portion defined by one layer of mesh is provided at first injection port 6a of injector 6 as in a conventional manner.
In plating apparatus 100, therefore, the plating targets are not moved upward excessively to a high position in the stored plating solution, even when the amount of the plating solution injected from injector 6 is increased, the time required for a single pass of each plating target through plating forming portion is reduced, and the number of f times each plating target circulates through the plating apparatus is increased. Thus, in plating apparatus 100, the occurrence of defects in the plating targets such as cracking, chipping, or peeling of the plated films due to the upward movement of the plating targets to a high position in the stored plating solution is reduced or prevented.
In plating apparatus 100, defects are unlikely to occur in the plating targets, even when the amount of the plating solution injected from injector 6 is increased, the time required for a single pass of each plating target through plating forming portion 4 is reduced, and the number of times each plating target circulates through the plating apparatus is increased, for the purpose of reduce or preventing the thickness variation in the plated film.
The following describes an example of a plating step performed using plating apparatus 100.
First, a desired plating solution is introduced into plating bath 1.
Then, the prescribed number of plating targets, media, and insulating balls are introduced into guide portion 13 inside plating bath 1. In this case, each of the plating targets, the media, and the insulating balls has a desired shape and desired dimensions. The introduction of the plating solution may be exchanged in order with the introduction of the plating targets, the media, and the insulating balls. The introduced plating targets, media, and insulating balls are deposited inside plating forming portion 4.
Then, pump 10 is driven to inject the plating solution from first injection port 6a of injector 6. As a result, an upward flow of the plating solution is generated inside metal pipe 2. Then, the plating targets, the media, and the insulating balls deposited inside plating forming portion 4 are partially removed from the lower end of plating forming portion 4, introduced into mixer 12, mixed with the injected plating solution, and then moved upward with the upward flow through metal pipe 2.
The plating targets, the media, and the insulating balls that have been moved upward through metal pipe 2 are jetted to the outside from the upper end of metal pipe 2 and then stirred.
The plating targets, the media, and the insulating balls that have been stirred are deposited on upper sides of other plating targets, media, and insulating balls that have already been deposited in plating forming portion 4.
As the plating targets, the media, and the insulating balls that have been deposited in plating forming portion 4 are partially removed from the lower end of plating forming portion 4 and introduced into mixer 12, the plating targets, the media, and the insulating balls that have been newly deposited gradually fall downward. In this way, the plating targets, the media, and the insulating balls circulate through plating apparatus 100.
Then, power supply 15 is driven to apply a current between metal pipe 2 defining and functioning as the first electrode and second electrode 5. As a result, plating on each plating target is started in plating forming portion 4.
When a prescribed time period has elapsed and a plated film having a desired thickness is formed on each plating target, power supply 15 is stopped to stop plating on each plating target. Then, pump 10 is stopped to stop circulation of the plating targets, the media, and the insulating balls through plating apparatus 100.
Then, the plating targets, the media, and the insulating balls are taken out from plating bath 1, the plating targets are then sorted out, and the plating step ends.
In order to check the effectiveness of the present invention, the following experiment was performed. Specifically, Example 1 was performed using the plating apparatus of an example embodiment of the present invention, and Comparative Example 1 and Comparative Example 2 were performed using plating apparatuses other than the plating apparatus of the present invention.
First, Example 1 was performed. In Example 1, plating apparatus 100 of the above-described example embodiment was used. In plating apparatus 100 of Example 1, first injection port 6a of injector 6 had a circular shape with a diameter of, for example, about 28 mm. In plating apparatus 100 of Example 1, plating forming portion 4 had a length of, for example, about 220 mm.
Mesh portion 7 shown in
A plating solution was accommodated in plating bath 1 of plating apparatus 100. A Ni plating solution, for example, was used as the plating solution.
Plating targets, media, and insulating balls were introduced into guide portion 13 inside plating bath 1 of plating apparatus 100. The total amount of blending of the plating targets, the media, and the insulating balls was, for example, about 1720 cc. The blending ratios were set at, for example, about 1376 cc (about 80% by volume) for the plating targets, about 86 cc (about 5% by volume) for the media, and about 258 cc (about 15% by volume) for the insulating balls.
Pump 10 was driven at low output to inject the plating solution from first injection port 6a of injector 6, to cause the plating targets, the media, and the insulating balls to circulate through mixer 12, hollow portion 2a of metal pipe 2, guide portion 13, plating forming portion 4, and mixer 12 in this order. The output of pump 10 was gradually increased to increase a speed of circulation of the plating targets, the media, and the insulating balls. Then, when the plating targets that were moved upward to a relatively high position (e.g., jetted upward) in the stored plating solution among the plating targets that were discharged from the upper end of hollow portion 2a of metal pipe 2 reached a prescribed height, the increasing of the output of pump 10 was stopped to keep the output of pump 10 constant. Specifically, when the plating targets that were moved upward to a relatively high position in the stored plating solution among the plating targets that were discharged from the upper end of hollow portion 2a of metal pipe 2 reached a position corresponding to about half the height between the upper end of metal pipe 2 and a fluid level of the plating solution accommodated in plating bath 1, the output of pump 10 was kept constant.
Then, power supply 15 was driven to apply a current between metal pipe 2 defining and functioning as the first electrode and second electrode 5, and plating on each plating target was started in plating forming portion 4.
In this state, the amount of the plating solution injected from first injection port 6a of injector 6 (the flow rate of the plating solution) was measured. Additionally, in this state, the time required for a single pass of each plating target through plating forming portion 4 was measured.
In Example 1, the amount of the plating solution injected from first injection port 6a of injector 6 was, for example, about 39 L/min. The time required for a single pass of each plating target through plating forming portion 4 was, for example, about 10.8 seconds.
Next, Comparative Example 1 was performed. In Comparative Example 1, a plating apparatus 1100 (not shown) that was obtained by partially modifying plating apparatus 100 of Example 1 was used.
Plating apparatus 1100 included a mesh portion 17 (not shown) that was obtained by modifying mesh portion 7 of Example 1. Specifically, mesh portion 17 of Comparative Example 1 had a single mesh structure defined by one layer of mesh having a mesh opening of, for example, about 900 μm over the entire surface.
In Comparative Example 1 as well, under the same conditions as those of Example 1, a plating solution was accommodated in plating bath 1, and plating targets, media, and insulating balls were introduced into guide portion 13 inside plating bath 1.
In Comparative Example 1 as well, under the same or substantially the same conditions as those of Example 1, pump 10 was driven at low output, and the output of pump 10 was gradually increased. Then, when the plating targets that were moved upward to a relatively high position in the stored plating solution among the plating targets that were discharged from the upper end of hollow portion 2a of metal pipe 2 reached the position corresponding to half the height between the upper end of metal pipe 2 and the fluid level of the plating solution accommodated in plating bath 1, the output of pump 10 was kept constant. Then, power supply 15 was driven to apply a current between metal pipe 2 defining and functioning as the first electrode and second electrode 5, and plating on each plating target was started in plating forming portion 4.
In Comparative Example 1 as well, in this state, the amount of the plating solution injected from first injection port 6a of injector 6, and the time required for a single pass of each plating target through plating forming portion 4 were measured.
In Comparative Example 1, the amount of the plating solution injected from first injection port 6a of injector 6 was, for example, about 35 L/min. In Comparative Example 1, the time required for a single pass of each plating target through plating forming portion 4 was, for example, about 18.4 seconds.
Next, Comparative performed. In Comparative Example 2, a plating apparatus 1200 (not shown) that was obtained by partially modifying plating apparatus 100 of Example 1 was used.
Plating apparatus 1200 included a mesh portion 27 (not shown) that was obtained by modifying mesh portion 7 of Example 1. Specifically, mesh portion 27 of Comparative Example 2 had a double mesh structure defined by two stacked layers of mesh having a mesh opening of, for example, about 900 μm over the entire or substantially the entire surface.
In Comparative Example 2 as well, under the same or substantially the same conditions as those of Example 1 and Comparative Example 1, a plating solution was accommodated in plating bath 1, and plating targets, media, and insulating balls were introduced into guide portion 13 inside plating bath 1.
In Comparative Example 2 as well, under the same conditions as those of Example 1 and Comparative Example 1, pump 10 was driven at low output, and the output of pump 10 was gradually increased. Then, when the plating targets that were moved upward to a relatively high position in the stored plating solution among the plating targets that were discharged from the upper end of hollow portion 2a of metal pipe 2 reached the position corresponding to half the height between the upper end of metal pipe 2 and the fluid level of the plating solution accommodated in plating bath 1, the output of pump 10 was kept constant. Then, power supply 15 was driven to apply a current between metal pipe 2 defining and functioning as the first electrode and second electrode 5, and plating on each plating target was started in plating forming portion 4.
In Comparative Example 2 as well, in this state, the amount of the plating solution injected from first injection port 6a of injector 6, and the time required for a single pass of each plating target through plating forming portion 4 were measured.
In Comparative Example 2, the amount of the plating solution injected from first injection port 6a of injector 6 was, for example, about 32 L/min. In Comparative Example 2, the time required for a single pass of each plating target through plating forming portion 4 was, for example, about 11.2 seconds.
Table 1 shows details and experimental results of Example 1, Comparative Example 1, and Comparative Example 2.
As can be seen from Table 1, under the condition that the output of pump 10 was kept constant (e.g., maintained) when the plating targets that were moved upward to a relatively high position in the stored plating solution among the plating targets that were discharged from the upper end of hollow portion 2a of metal pipe 2 reached the position corresponding to half the height between the upper end of metal pipe 2 and the fluid level of the plating solution accommodated in plating bath 1, the flow rate of the plating solution was higher and the time required for a single pass of each plating target through plating forming portion 4 was shorter in Example 1 than in Comparative Example 1 and Comparative Example 2.
In view of the foregoing, according to example embodiments of the present invention, it was discovered that the flow rate of the plating solution could be increased, and the time required for a single pass of each plating target through plating forming portion 4 could be reduced, as compared to the structure in which the mesh portion is a single mesh over the entire surface (Comparative Example 1) and the structure in which the mesh portion is a double mesh over the entire surface (Comparative Example 2), while the occurrence of defects in the plating targets such as cracking, chipping, or peeling of the plated films is reduced or prevented.
According to example embodiments of 41 the present invention, it was possible to increase the flow rate of the plating solution, increase the number of times each plating target circulates through the plating apparatus, and reduce or prevent the thickness variation in the formed plated film, while reduce or preventing the occurrence of defects in the plating targets.
As above, the plating apparatus according to an example embodiment has been described. However, the present invention of the subject application is not limited to the above-described details, but can be variously modified in accordance with the gist of the present invention.
For example, while central portion 7c of mesh portion 7 preferably includes a double mesh structure and circumferential portion 7d of mesh portion 7 preferably includes a single mesh structure in the above-described example embodiment, the present invention is not limited to this structure. For example, if the amount of the passing plating solution should be further reduced or prevented in central portion 7c of mesh portion 7, central portion 7c may have a triple mesh structure, a quadruple mesh structure, or a more multiple mesh structure.
Mesh portion 7 is not required to be defined by only central portion 7c and circumferential portion 7d when viewed in the planar direction. For example, an intermediate portion may be provided between central portion 7c and circumferential portion 7d. For example, central portion 7c may have a tripe mesh structure, the intermediate portion may have a double mesh structure, and circumferential portion 7d may have a single mesh structure.
The plating apparatus according to one example embodiment of the present invention is as described above.
In this plating apparatus, it is also preferable that a metal pipe having a cylindrical shape and having a hollow portion is provided directly above the injector. In this case, the high speed of the plating solution flow that is moved upward through a central portion inside the metal pipe can be reduced or prevented (e.g., reduced).
It is also preferable that the number of layers of the mesh in the circumferential portion is one, and the number of layers of the mesh in the central portion is two. In this case, the mesh portion can be easily fabricated.
It is also preferable that in the mesh portion, a mesh opening of the central portion is smaller than a mesh opening of the circumferential portion when viewed in the planar direction. In this case, the mesh portion can reduce or prevent the amount of the plating solution passing through the central portion to be lower than the amount of the plating solution passing through the circumferential portion.
It is also preferable that the central portion has a circular shape when viewed in the planar direction. In this case, the mesh portion can allow the plating solution to uniformly pass through the mesh portion in all radial directions from the center of the mesh portion.
It is also preferable that the central portion has a polygonal shape when viewed in the planar direction. In particular, it is also preferable that the central portion has a quadrangular shape when viewed in the planar direction. In this case, the mesh portion can be easily fabricated.
It is also preferable that the injector has an inner cylindrical shape having a bottom surface and an inner wall, with the first injection port provided in an upper end thereof. A second injection port is provided in the bottom surface. An opening area of the second injection port is smaller than an opening area of the first injection port. The plating solution is injected into the injector from the second injection port. In this case, the diameter of the first injection port that injects the plating solution to the plating bath from the injector can be made larger than the diameter of the pipe connected to the second injection port, so that the speed of the plating solution injected from the first injection port can be made uniform (e.g., the difference between fast and slow portions can be reduced) while the plating solution passes through the injector.
It is also preferable that the plating apparatus includes a metal pipe having a cylindrical shape and including a hollow portion, the metal pipe defining and functioning as a first electrode, a partition wall pipe made of an electrically insulating material, the partition wall pipe having a cylindrical shape and including a hollow portion, the partition wall pipe being provided with a plurality of holes through which the plating solution passes but through which the plating targets do not pass, and a second electrode. The metal pipe, the partition wall pipe, and the second electrode are each accommodated in the plating bath. The metal pipe is located inside the hollow portion of the partition wall pipe, and a plating forming portion is formed between an inside of the partition wall pipe and an outside of the metal pipe. The second electrode is disposed outside the partition wall pipe. The injector is provided below the metal pipe. The plating targets are moved upward through the hollow portion of the metal pipe with an upward flow of the plating solution injected from the injector. The plating targets are discharged to an outside from an upper end of the hollow portion of the metal pipe and stirred in the plating solution. The plating targets subsequently fall downward through the plating forming portion. While the plating targets fall downward, the plating targets each are plated by application of a current between the metal pipe defining and functioning as the first electrode and the second electrode. In this case, the speed of the plating solution that is moved upward through the metal pipe can be controlled, and in particular, the high speed of the plating solution flow that is moved upward through a central portion inside the metal pipe can be reduced or prevented (e.g., reduced). The first electrode is a cathode electrode, for example, and the second electrode is an anode electrode, for example.
While example embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-154283 | Sep 2022 | JP | national |
This application is a Continuation Application of PCT Application No. PCT/JP2023/028659, filed on Aug. 5, 2023, and claims the benefit of priority to Japanese Patent Application No. 2022-154283, filed on Sep. 27, 2022. The entire contents of each application are hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2023/028659 | Aug 2023 | WO |
| Child | 18984870 | US |
