Patent Application
20200270760
The present invention relates to a regulation plate, a plating apparatus equipped with the regulation plate, and a plating method.
Conventionally, wiring is formed in minute wiring grooves, holes, or resist openings provided on surfaces of substrates such as semiconductor wafers or bumps (bumpy electrodes) used to electrically connect to electrodes of a package which are formed on the surfaces of the substrates. As a method for forming the wiring and bumps, an electrolytic plating process, vacuum deposition process, printing process, ball bumping process, and the like are known, for example. With increases in I/O counts and pitch refinement on semiconductor chips, the electrolytic plating process which allows refinement and shows comparatively stable performance has come to be used frequently.
When wiring or bumps are formed by the electrolytic plating process, a seed layer (feeder layer) with low electrical resistance is formed on surfaces of barrier metal provided in the wiring grooves, holes, or resist openings in the substrates. A plating film grows on a surface of the seed layer. In recent years, seed layers with thinner film thickness have come to be used along with refinement of wiring and bumps. With decreases in the film thickness of the seed layer, the electrical resistance (sheet resistance) of the seed layer increases.
Generally, a substrate to be plated has an electrical contact on its periphery. Consequently, an electric current corresponding to combined resistance of an electrical resistance value of the plating solution and electrical resistance value of the seed layer between a central portion of the substrate and the electrical contact flows through the central portion of the substrate. On the other hand, an electric current almost corresponding to the electrical resistance value of the plating solution flows through the periphery (near the electrical contact) of the substrate. That is, the flow of the electric current to the central portion of the substrate is resisted to an extent corresponding to the electrical resistance value of the seed layer between the central portion of the substrate and the electrical contact. The phenomenon in which electric current concentrates on the periphery of a substrate is referred to as a terminal effect.
In the case of a substrate which has a seed layer comparatively thin in film thickness, the electrical resistance value of the seed layer between the central portion of the substrate and the electrical contact is comparatively high. Therefore, in plating a substrate whose seed layer is comparatively thin in film thickness, the terminal effect is prominent. Consequently, the plating rate in the central portion of the substrate falls, making the plating film in the central portion of the substrate thinner in film thickness than the plating film in the periphery of the substrate and resulting in reduced in-plane uniformity of film thickness.
In order to curb the reduction in the in-plane uniformity of film thickness due to the terminal effect, it is necessary to adjust an electric field applied to the substrate. For example, a plating apparatus is known, in which a regulation plate is installed between an anode and substrate to regulate a potential distribution between the anode and substrate (see PTL 1).
PTL 1: Japanese Patent Laid-Open No. 2005-029863
Now, the influence of the terminal effect varies with the degree of film thickness of the seed layer on the substrate. Specifically, as described above, when the seed layer is comparatively thin in film thickness, since the sheet resistance is comparatively high, the influence of the terminal effect appears prominently. On the other hand, when the seed layer is comparatively thick in film thickness, since the sheet resistance is comparatively low, the influence of the terminal effect is comparatively small.
Also, the influence of the terminal effect can vary not only with the degree of film thickness of the seed layer, but also with the other factors. For example, when a resist aperture ratio of the substrate is comparatively high, the plating film formed on the substrate has a comparatively large area, where the resist aperture ratio is the area ratio of a portion not covered with resist (open portion of the resist) to a region bordered by an outer edge of the resist. Therefore, as the plating film is formed on the substrate, the formed plating film causes electric current to flow readily in the central portion of the substrate as well. In other words, as the plating film is formed on the substrate, the electrical resistance value between the central portion of the substrate and the electrical contact decreases, gradually reducing the influence of the terminal effect. On the other hand, when the resist aperture ratio of the substrate is comparatively low, the area of the plating film formed on the substrate is relatively small. Consequently, when the resist aperture ratio of the substrate is comparatively low, even if a plating film is formed on the substrate, variation in the electrical resistance value between the central portion of the substrate and the electrical contact is smaller than when the resist aperture ratio of the substrate is comparatively high, and thus the influence of the terminal effect remains large.
Also, when the electrical resistance value of a plating solution used to process the substrate is comparatively high, the influence of the terminal effect is smaller than when the electrical resistance value of the plating solution used to process the substrate is comparatively low. Specifically, if the electrical resistance value of the plating solution is R1 and the electrical resistance value of the seed layer between the central portion of the substrate and the electrical contact is R2, an electric current corresponding to combined resistance value (R1 +R2) flows through the central portion of the substrate. On the other hand, an electric current almost corresponding to the electrical resistance value R1 of the plating solution flows through the periphery (near the electrical contact) of the substrate. Thus, as the electrical resistance value R1 increases, the influence of the electrical resistance value R2 to the electric current flowing through the central portion of the substrate decreases, reducing the influence of the terminal effect.
In this way, the influence of the terminal effect varies with characteristics of the substrate, conditions for processing the substrate, and the like. Therefore, when plural substrates differing in the influence of the terminal effect are plated one after another using a single plating apparatus, in order to curb the reduction in the in-plane uniformity of film thickness due to the terminal effect, it is necessary to adjust the electric fields applied to the substrates, according to the characteristics of the respective substrates, conditions for processing the substrates, and the like. However, in order to adjust the electric fields according to the characteristics of the substrates, conditions for processing the substrates, and the like using a regulation plate such as described in PTL 1, it is necessary to prepare plural regulation plates which suit the characteristics of the substrates, conditions for processing the substrates, and the like.
Besides, even if plural regulation plates are prepared, each time substrates differing in characteristics and processing conditions are processed, it is necessary to take the regulation plate out of the plating bath and install another regulation plate, involving time and effort.
The present invention has been made in view of the above problems and has an object to provide a regulation plate, a plating apparatus equipped with the regulation plate, and a plating method which can curb reduction in in-plane uniformity due to influence of a terminal effect in plating plural substrates differing in characteristics and processing conditions.
A first form provides a regulation plate used to adjust an electric current between an anode and a substrate to be plated. The regulation plate comprises: a plate main body provided with a rim forming a first opening adapted to allow passage of an electric current; plural first blades used to narrow a diameter of the first opening; and a first moving mechanism adapted to translate the plural first blades in a radial direction of the first opening.
The first form allows the diameter of the opening to be adjusted by narrowing a diameter of an opening in the regulation plate using the first blades. This makes it possible to curb reduction in in-plane uniformity due to influence of a terminal effect when a first substrate and second substrate differ from each other in characteristics or processing conditions. Specifically, in plating the substrate under conditions in which the influence of the terminal effect appears prominently, by reducing the diameter of the opening in the regulation plate, the film deposition rate on the periphery of the substrate can be slowed down, making it possible to improve the in-plane uniformity on the substrate. Also, since the first blades are configured to perform translational movement, the plural first blades can move in the radial direction while maintaining an angular relationship among the first blades. Therefore, a perfectly circular shape of the opening formed by the first blades can be maintained better than when plural aperture blades rotate around a predetermined axis, reducing the diameter of the opening as with an aperture mechanism of a camera.
According to a second form, in the first form, the first moving mechanism includes a ring member placed along the rim; either of the ring member and the plural first blades includes a slide slot inclined in the radial direction of the first opening; and another of the ring member and the plural first blades includes a slide pin adapted to slide along the slide slot.
According to the second form, the slide pin provided on the other of the ring member and the plural first blades slide along the slide slot provided in either of the ring member and the plural first blades. Therefore, as the ring member is rotated in a circumferential direction, the slide pin slide along the slide slot, allowing the first blades to move in the radial direction of the first opening.
According to a third form, in the second form, the first moving mechanism includes a blade presser member fixed on a side opposite the ring member of the plural first blades; either of the blade presser member and the plural first blades includes a guide slot formed in parallel to a translation direction of the first blades; and another of the blade presser member and the plural first blades includes a guide pin adapted to slide along the guide slot.
According to the second form, the guide pins provided in the other of the blade presser member and the plural first blades slide along the guide slots provided in either of the blade presser member and the plural first blades. Therefore, when the plural first blades is moved by the moving mechanism, the first blades can be translated in a desired direction while preventing the plural first blades from performing rotary motion.
According to a fourth form, in the second or third form, the first moving mechanism includes a rotating member used to rotate the ring member in a circumferential direction; and the rotating member includes a ring portion fixed to the ring member, and a lever portion adapted to rotate the ring portion in the circumferential direction.
According to the fourth form, as the lever portion is operated by an actuator or by hand, the ring portion can be rotated in the circumferential direction. Since the ring portion is fixed to the ring member, the ring member rotates along with rotation of the ring portion. Consequently, the slide slots or slide pins provided in/on the ring member slide with respect to the slide pins or slide slots provided on/in the plural first blades, making it possible to translate the plural first blades.
According to a fifth form, in the fourth form, either of the plate main body and the ring member includes a support slot formed along a rotation direction of the ring member; and another of the plate main body and the ring member includes a support pin slidably engaged with the support slot.
According to the fifth form, the support pin provided on the other of the plate main body and the ring member is slidably engaged with the support slot provided in either of the plate main body and the ring member. As the support pin gets engaged with the support slot, the ring member is supported by the plate main body. Since the support slot is formed along the rotation direction of the ring member, the ring member can be rotated when the support pin slides along the support slot.
According to a sixth form, in any one of the first to fifth forms, an inner peripheral edge of each of the plural first blades is formed into an arc shape and is overlapped with other first blades, forming a substantially circular inner peripheral edge.
According to the sixth form, when the plural first blades perform translational movement in the radial direction of the first opening, reducing the diameter of the opening, the inner peripheral edges of the plural first blades can maintain a substantially circular shape.
According to a seventh form, in any one of the first to sixth forms, the regulation plate further comprises: plural second blades placed at a position shifted from the plural first blades in a direction orthogonal to the radial direction of the first opening and used to narrow the diameter of the first opening; and a second moving mechanism adapted to translate the plural second blades in the radial direction of the first opening.
According to the seventh form, the regulation plate includes formed by the plural first blades and an opening having a second diameter formed by the plural second blades. By appropriately adjusting sizes of the first diameter and second diameter, it is possible to more appropriately adjust the electric current passing through the opening in the regulation plate.
According to an eighth form, in the seventh form, the plural first blades and the plural second blades are arranged such that a straight line joining a center of an opening formed by the first blades and a center of an opening formed by the second blades is orthogonal to the radial direction of the openings.
According to the eighth form, the first blades and the second blades are arranged such that the center of the opening formed by the first blades and the center of the opening formed by the second blades will coincide each other. Therefore, when positioning the regulation plate in a plating bath, there is no need to position the center of the opening formed by the plural first blades and the center of the opening formed by the plural second blades separately. Consequently, even when high accuracy is required of the center position of the opening in the regulation plate, the regulation plate can be positioned easily.
A ninth form provides a regulation plate used to adjust an electric current between an anode and a substrate to be plated. The regulation plate comprises: a first plate main body provided with a first rim forming a first opening adapted to allow passage of an electric current and plural first blades used to narrow a diameter of the first opening; and a second plate main body provided with a second rim forming a second opening adapted to allow passage of an electric current and plural second blades used to narrow a diameter of the second opening. The first plate main body and the second plate main body are coupled together such that a straight line joining a center of an opening formed by the plural first blades and a center of an opening formed by the plural second blades is orthogonal to the radial direction of the openings.
According to the ninth form, the regulation plate includes the opening having a first diameter formed by the plural first blades and the opening having a second diameter formed by the plural second blades. By appropriately adjusting sizes of the first diameter and second diameter, it is possible to more appropriately adjust the electric current passing through the opening in the regulation plate. Also, the first blades and the second blades are arranged such that the center of the opening formed by the first blades and the center of the opening formed by the second blades will coincide each other. Therefore, when positioning the regulation plate in a plating bath, there is no need to position the center of the opening formed by the plural first blades and the center of the opening formed by the plural second blades separately. Consequently, even when high accuracy is required of the center position of the opening in the regulation plate, the regulation plate can be positioned easily.
According to a tenth form, in any one of the seventh to ninth forms, the diameter of the opening formed by the plural first blades and the diameter of the opening formed by the plural second blades are configured to be adjustable independently of each other.
According to the tenth form, the diameter of the opening defined by the plural first blades and the diameter of the opening defined by the plural second blades can be made different from each other. This makes it possible to decrease the diameters of the openings in stages according to the characteristics or processing conditions of the substrate, such as reducing the diameter of the opening defined by the blades closer to the substrate and increasing the diameter of the opening defined by the blades farther from the substrate.
An eleventh form provides a plating apparatus. The plating apparatus comprises: an anode holder configured to hold an anode; a substrate holder placed opposite the anode holder and configured to hold a substrate; an anode mask mounted integrally on the anode holder and provided with a second opening adapted to allow passage of an electric current flowing between the anode and the substrate; and any of the regulation plates described above, wherein the anode mask includes an adjustment mechanism adapted to adjust a diameter of the second opening.
According to the eleventh form, the diameter of the second opening of the anode mask can be adjusted for each of a first substrate and second substrate. This makes it possible to curb reduction in in-plane uniformity due to influence of a terminal effect when the first substrate and second substrate differ from each other in characteristics or processing conditions. Specifically, when the second substrate is plated under conditions in which the influence of the terminal effect appears prominently, by reducing the diameter of the second opening, it is possible to concentrate an electric field on a central portion of the substrate and thereby increase film thickness in the central portion of the substrate. Also, if the diameter of the first opening in the regulation plate is reduced, the film deposition rate on the periphery of the substrate can be slowed down. Thus, if both the diameter of the first opening in the regulation plate and the diameter of the second opening of the anode mask are adjusted, the in-plane uniformity on the substrate W can be further improved.
A twelfth form provides a plating method. The plating method comprises: placing an anode holder in a plating bath, where the anode holder is integrally provided with an anode mask having a first opening adapted to allow passage of an electric current flowing between an anode and a substrate; placing a substrate holder adapted to hold a first substrate in the plating bath; placing a regulation plate between the anode mask and the substrate, where the regulation plate includes a second opening and third opening adapted to allow passage of the electric current flowing between the anode and the substrate; plating the first substrate by adjusting a diameter of the first opening to a first diameter; placing a substrate holder adapted to hold a second substrate in the plating bath; and plating the second substrate by adjusting a diameter of the first opening to a second diameter smaller than the first diameter and by changing the diameters of the second opening and third opening in the regulation plate.
According to the twelfth form, the diameter of the first opening in the anode mask can be adjusted for each of the first substrate and second substrate. This makes it possible to curb reduction in in-plane uniformity due to influence of a terminal effect when the first substrate and second substrate differ from each other in characteristics or processing conditions. Specifically, when the second substrate is plated under conditions in which the influence of the terminal effect appears prominently, by reducing the diameter of the first opening, it is possible to concentrate an electric field on a central portion of the substrate and thereby increase film thickness in the central portion of the substrate. Also, by changing the diameters of the second opening and third opening in the regulation plate, the film deposition rate on the periphery of the substrate can be slowed down, making it possible to improve the in-plane uniformity on the substrate W.
An embodiment of the present invention will be described below with reference to the drawings. In the drawings described below, same or equivalent components are denoted by the same reference numerals, and redundant description thereof will be omitted.
As shown in
The anode holder 20 holding the anode 21 and substrate holder 40 holding the substrate W are immersed in the plating solution Q in the plating treatment bath 52 and installed there facing each other such that the anode 21 and a surface-to-be-plated W1 of the substrate W will be substantially parallel to each other. A voltage is applied by a plating power supply 59 to the anode 21 and substrate W immersed in the plating solution Q in the plating treatment bath 52. Consequently, the metal ions are reduced on the surface-to-be-plated W1 of the substrate W, forming a film on the surface-to-be-plated W1.
The plating treatment bath 52 has a plating solution supply port 56 for use to supply the plating solution Q into the bath. The plating solution discharge bath 54 has a plating solution discharge port 57 for use to discharge the plating solution Q overflowing from the plating treatment bath 52. The plating solution supply port 56 is located at a bottom of the plating treatment bath 52 while the plating solution discharge port 57 is located at a bottom of the plating solution discharge bath 54.
When supplied to the plating treatment bath 52 through the plating solution supply port 56, the plating solution Q overflows from the plating treatment bath 52, gets over the partition wall 55, and flows into the plating solution discharge bath 54. After flowing into the plating solution discharge bath 54, the plating solution Q is discharged through the plating solution discharge port 57, and impurities are removed by a filter and the like of a plating solution circulation unit 58. The plating solution Q with the impurities removed therefrom is supplied to the plating treatment bath 52 through the plating solution supply port 56 by the plating solution circulation unit 58.
The anode holder 20 includes an anode mask 25 adapted to adjust an electric field between the anode 21 and substrate W. The anode mask 25 is a substantially plate-like member made, for example, of a dielectric material and is installed on a front face of the anode holder 20. The front face of the anode holder 20 here is a face on the side facing the substrate holder 40. That is, the anode mask 25 is placed between the anode 21 and substrate holder 40. The anode mask 25 has an opening 25a (which is an example of a second opening) in an approximate central portion thereof, where an electric current flowing between the anode 21 and substrate W passes through the opening 25a. Preferably the opening 25a is smaller in diameter than the anode 21. As described later, the diameter of the opening 25a in the anode mask 25 is configured to be adjustable.
The anode mask 25 has an anode mask mount 25b on its outer circumference to mount the anode mask 25 integrally on the anode holder 20. Note that the position of the anode mask 25 can be between the anode holder 20 and substrate holder 40, but preferably the anode mask 25 is closer to the anode holder 20 than the intermediate position between the anode holder 20 and substrate holder 40. Also, for example, the anode mask 25 may be placed on the front face of the anode holder 20 without being mounted on the anode holder 20. However, when the anode mask 25 is attached to the anode holder 20 as with the present embodiment, the position of the anode mask 25 relative to the anode holder 20 is fixed, making it possible to prevent displacement between the position of the anode 21 and position of the opening 25a.
Preferably the anode 21 held by the anode holder 20 is an insoluble anode. When the anode 21 is an insoluble anode, the anode 21 does not dissolve even when the plating process progresses, and the shape of the anode 21 remains unchanged. Consequently, since the positional relationship (distance) between the anode mask 25 and anode 21 does not change, it is possible to prevent changes in the electric field between the anode 21 and substrate W, which would be caused by changes in the positional relationship between the anode mask 25 and a surface of anode 21.
The plating apparatus 10 further includes a regulation plate 60 adapted to adjust the electric field between the anode 21 and substrate W. The regulation plate 60 is a substantially flat-plate member made, for example, of a dielectric material and is installed between the anode mask 25 and substrate holder 40 (substrate W). The regulation plate 60 includes an opening 60a (which is an example of a first opening) adapted to allow passage of the electric current flowing between the anode 21 and substrate W. Preferably the opening 60a is smaller in diameter than the substrate W. As described later, the diameter of the opening 60a in the regulation plate 60 is configured to be adjustable.
Preferably the regulation plate 60 is closer to the substrate holder 40 than the intermediate position between the anode holder 20 and substrate holder 40. The closer to the substrate holder 40 the regulation plate 60 is placed, the more accurately the film thickness on the periphery of the substrate W can be controlled by adjusting the diameter of the opening 60a in the regulation plate 60.
A paddle 18 is installed between the regulation plate 60 and substrate holder 40 to stir the plating solution Q near the surface-to-be-plated W1 of the substrate W. The paddle 18 is a substantially rod-shaped member and is installed in the plating treatment bath 52, extending in a vertical direction. One end of the paddle 18 is fixed to a paddle drive unit 19. The paddle 18 is moved by the paddle drive unit 19 horizontally along the surface-to-be-plated W1 of the substrate W, thereby stirring the plating solution Q.
Next, the anode mask 25 shown in
As shown in
As shown in
The aperture blades 27 are used in conjunction, for example, to manually increase and decrease the diameter of the opening 25a. Also, the aperture blades 27 may be configured to be driven together by means of pneumatic pressure or an electric driving force. The adjustment mechanism which uses the aperture blades 27 features the capability to make the opening 25a variable in a comparatively wide range. Also, when the substrate is circular, desirably the opening 25a in the anode mask 25 is circular. However, with the opening 25a whose diameter is variable in a comparatively wide range, it is mechanically difficult to maintain a completely circular shape in an entire range of the opening 25a from minimum diameter to maximum diameter. Generally, when the opening adapted to allow the passage of the electric current flowing between the anode 21 and substrate W is not completely circular, an azimuth distribution in an electric field becomes nonuniform and consequently the shape of the opening may be transferred to a thickness distribution of a plating film formed on the periphery of the substrate W. However, since the anode mask 25 is mounted integrally on the anode holder 20, allowing a sufficient distance from the substrate, the influence on the plating film thickness distribution can be minimized even when the opening is not completely circular.
Next, the regulation plate 60 shown in
As shown in
As shown in
The blade body 70 is located on a front side of the rim 64 of the regulation plate 60 and is provided with plural first blades 71 used to narrow the diameter of the opening 60a. Note that according to the present embodiment, the front side of the regulation plate 60 corresponds to the plane opposed to the substrate holder 40 shown in
The ring member 80 is configured to translate the plural first blades 71 in the radial direction of the opening 60a. The ring member 80 is placed along the rim 64 of the regulation plate 60. According to the present embodiment, the ring member 80 is placed along an inner circumferential surface of the rim 64 of the regulation plate 60. However, this is not restrictive, and the ring member 80 may be placed, for example, on a front side of the rim 64 of the regulation plate 60.
The blade presser member 90 is placed on a front side of the blade body 70 (on a side opposite the ring member 80). The rotating member 100 is placed on a rear side of the plate main body 61 and integrated with the ring member 80 as described later. Members making up regulation plate 60 will be described in detail below.
Four projections 104 are provided on a circumference of the ring portion 101, and a support slot 103 is formed in each of the projections 104 along the circumferential direction of the ring portion 101. As described later, the support slots 103 are slidably supported by support pins fixed to the pin holes 65 in the plate main body 61 shown in
A slide pin 72 configured to slide along a slide slot 81 in the ring member 80 shown in
Also, guide pins 73 configured to slide along guide slots 91 in the blade presser member 90 shown in
The blade presser member 90 is placed such that a rear side of the blade presser member 90 will be put in contact with the front side of the blade body 70. Therefore, when performing translational movement in the radial direction of the opening 60a, the first blades 71 of the blade body 70 perform translational movement in contact with the blade presser member 90. To reduce abrasion of the blade presser member 90 and first blades 71, preferably the blade presser member 90 is made, for example, of a low-friction resin such as PTFE.
Next, a mechanism for translating the first blade 71 shown in
As shown in
When the lever portion 102 of the rotating member 100 moves in the direction of arrow A1 or A2, i.e., in the circumferential direction of the ring portion 101, the non-illustrated ring member 80 coupled to the ring portion 101 also rotates in the circumferential direction. For example, when the lever portion 102 moves in the direction of arrow A1 (clockwise in
Also, for example, when the lever portion 102 moves in the direction of arrow A2 (counterclockwise in
The plural first blades 71 perform translational movement in the radial direction similarly to one another. Therefore, the plural first blades can move in the radial direction while maintaining an angular relationship among the first blades 71. Consequently, a perfectly circular shape formed by the inner peripheral edges of the plural first blades 71 can be maintained better than when plural aperture blades rotate around a predetermined axis, reducing the diameter of the opening as with an aperture mechanism of a camera.
Four support pins 105 are provided on the plate main body 61. The support pins 105 slidably engage with the support slots 103 provided in the projections 104 on the ring portion 101. Consequently, when the lever portion 102 is operated, the ring portion 101 is guided to rotate in the circumferential direction along the support slots 103.
As shown in
The lever portion 102 may be operated, for example, automatically by a mechanical actuator or manually by an operator. Also, the lever portion 102 can be fixed at any position between the pair of stoppers 67.
As described above, the regulation plate 60 according to the present embodiment allows the diameter of the opening 60a to be adjusted by narrowing the diameter of the opening 60a using the plural first blades 71. This makes it possible to curb reduction in in-plane uniformity due to influence of a terminal effect when the first substrate and second substrate differ from each other in characteristics or processing conditions. Specifically, in plating the substrate under conditions in which the influence of the terminal effect appears prominently, by reducing the diameter of the opening a in the regulation plate 60, the film deposition rate on the periphery of the substrate can be slowed down, making it possible to improve the in-plane uniformity on the substrate. Also, since the first blades 71 are configured to perform translational movement, the plural first blades 71 can move in the radial direction while maintaining an angular relationship among the first blades 71. Therefore, a perfectly circular shape formed by the inner peripheral edges of the plural first blades 71 can be maintained better than when plural aperture blades rotate around a predetermined axis, reducing the diameter of the opening as with an aperture mechanism of a camera.
Note that according to the present embodiment, the first blades 71 have the slide pins 72 while the ring member 80 has the slide slots 81. However, this is not restrictive, and the ring member 80 may have slide pins 72 and the first blades 71 may have corresponding slide slots 81. Even when the first blades 71 and ring member 80 are configured in this way, as the ring member 80 rotates in the circumferential direction, the slide pins 72 slide in the slide slots 81, allowing the first blades 71 to move in the radial direction.
According to the present embodiment, the first blades 71 have the guide pins 73 and the blade presser member 90 have the guide slots 91. However, this is not restrictive, and the blade presser member 90 may have the guide pins 73 and the first blades 71 may have corresponding guide slots 91. Even when the first blades 71 and blade presser member 90 are configured in this way, as the first blades 71 are moved by the ring member 80, the guide pins 73 slide in the guide slots 91, making it possible to prevent circumferential movement and rotary motion of the first blades 71.
According to the present embodiment, the projections 104 provided with the support slots 103 are formed on the ring portion 101 of the rotating member 100 and the support pins 105 are fixed to the plate main body 61. However, this is not restrictive, and the ring portion 101 of the rotating member 100 may have support pins 105 and the plate main body 61 may have corresponding support slots 103. Even when the rotating member 100 and plate main body 61 are configured in this way, as the ring portion 101 is swung by the lever portion 102, the support pins 105 slide in the support slots 103, allowing the ring portion 101 to rotate in the circumferential direction.
Furthermore, according to the present embodiment, the regulation plate 60 includes only the blade body 70 (plural first blades 71) as a means of reducing the diameter of the opening 60a. However, the regulation plate 60 may include plural second blades other than the plural first blades 71, and a mechanism for translating the plural second blades. In this case, the plural second blades are placed at a position shifted from the plural first blades 71 in a direction orthogonal to the radial direction of the opening 60a. The mechanism for translating the plural second blades is identical with the above-mentioned mechanism for translating the plural first blades 71, and consequently the plural second blades perform translational movement in the radial direction of the opening 60a. Concrete examples will be described below with reference to drawings.
As shown in
The first plate main body 61A includes an opening portion 69A used to expose a handle 105A of a rotating member 100A to the outside. Also, the second plate main body 61B includes an opening portion 69B used to expose a handle 105B of a rotating member 100B to the outside. The handle 105A exposed from the opening portion 69A and the handle 105B exposed from the opening portion 69B can be operated independently of each other by any actuator or by hand. This makes it possible to translate the plural first blades 71A shown in
The first plate main body 61A has a first opening 169A in an approximate central portion thereof to allow passage of an electric current. Also, the second plate main body 61B has a second opening 169B in an approximate central portion thereof to allow passage of an electric current. The first plate main body 61A and second plate main body 61B are coupled together in such a way that a center of the first opening 169A and a center of the second opening 169B will be concentric. In other words, the first plate main body 61A and second plate main body 61B are coupled together in such a way that a straight line joining the center of the first opening 169A and the center of the second opening 169B will be orthogonal to radial directions of the respective openings.
The first plate main body 61A and second plate main body 61B are coupled together in such a way that a center of an opening formed by the plural first blades 71A shown in
In this way, the regulation plate 60 provided with the plural first blades 71A and plural second blades 71B allows the diameter of the opening 60a to be narrowed by both the plural first blades 71A and plural second blades 71B. In this case, the plural first blades 71A and plural second blades 71B allow the film deposition rate on the periphery of the substrate to be further slowed down. This makes it possible to improve the in-plane uniformity on the substrate whose film thicknesses tends to increase on the periphery.
When installing plural conventional regulation plates in a plating bath, it is necessary to position the center of an opening with respect to each of the plural regulation plates, taking a lot of trouble. In contrast, when plural first blades 71A and plural second blades 71B can be installed in a common regulation plate 60, the center of the opening formed by the first blades 71A and the center of the opening formed by the second blades 71B are fixed relatively. Therefore, when positioning the regulation plate 60 in a plating bath, there is no need to position the center of the opening formed by the plural first blades 71A and the center of the opening formed by the plural second blades 71B separately. Consequently, even when high accuracy is required of the center position of the opening in the regulation plate 60, the regulation plate 60 can be positioned easily.
Also, since the blade body 70A of the regulation plate 60 is made up of the plural first blades 71A, the shape of the opening of the blade body 70A is not perfectly circular in a strict sense. Consequently, it is difficult to completely remove variations in an electric field applied to the substrate W, where the variations are caused by the shape of the opening. However, since the plural second blades 71B are provided, electric field variations caused by the opening shape formed by the plural first blades 71A and electric field variations caused by the opening shape formed by the plural second blades 71B cancel out each other, reducing the electric field variations and making it possible to bring the plating film formed on the substrate W close to a perfect circle.
Furthermore, in the regulation plate 60, as shown in
Also, in the regulation plate 60 provided with the plural first blades 71A and plural second blades 71B, the diameter of the opening 60A defined by the plural first blades 71A and the diameter of the opening 60B defined by the plural second blades 71B can be made different from each other. This makes it possible to decrease the diameters of the openings in stages according to the characteristics or processing conditions of the substrate, such as reducing the diameter of the opening defined by the blades closer to the substrate and increasing the diameter of the opening defined by the blades farther from the substrate.
Next, description will be given of the process of plating the substrate W using the plating apparatus 10 shown in
By adjusting the diameter of at least the opening 25a in the anode mask 25 according to the characteristics of the substrates W or conditions for processing the substrates W, the plating apparatus 10 of the present embodiment can curb the reduction in the in-plane uniformity of the plating film on the substrates W.
Specifically, when the resist aperture ratio of the second substrate is lower than the resist aperture ratio of the first substrate, as described above, even if a plating film is formed on the second substrate, variation in the electrical resistance value between the central portion of the second substrate and the electrical contact is smaller than in the case of the first substrate whose resist aperture ratio is comparatively high. Consequently, even if a plating film is formed to some extent on the second substrate, the influence of the terminal effect on the second substrate remains large. Therefore, when the first substrate and second substrate are plated by keeping the conditions other than the resist aperture ratios of the substrates equal, the film thickness of the second substrate becomes larger in a peripheral portion of the substrate and relatively smaller in the central portion the substrate than the film thickness of the first substrate. Thus, the diameter of the opening 25a in the anode mask 25 is set smaller when the second substrate is plated using the plating apparatus 10 than when the first substrate is plated. This makes it possible to increase the film thickness in the central portion of the second substrate. Consequently, the reduction in in-plane uniformity due to the influence of the terminal effect can be curbed on both the first substrate and second substrate.
Also, when a seed layer of the second substrate is thinner than a seed layer of the first substrate, the terminal effect on the second substrate becomes prominent as described above. Therefore, when the first substrate and second substrate are plated by keeping the conditions other than the thickness of the seed layer equal, the film thickness of the second substrate becomes larger in the peripheral portion of the substrate and relatively smaller in the central portion the substrate than the film thickness of the first substrate. Thus, the diameter of the opening 25a in the anode mask 25 is set smaller when the second substrate is plated using the plating apparatus 10 than when the first substrate is plated. This makes it possible to increase the film thickness in the central portion of the second substrate. Consequently, the reduction in in-plane uniformity due to the influence of the terminal effect can be curbed on both the first substrate and second substrate.
Furthermore, when the second substrate is plated using a plating solution with a lower electrical resistance value than the plating solution used for the first substrate, the terminal effect on the second substrate becomes prominent as described above. Therefore, when the first substrate and second substrate are plated by keeping the conditions other than the electrical resistance value equal, the film thickness of the second substrate becomes larger in the peripheral portion of the substrate and relatively smaller in the central portion the substrate than the film thickness of the first substrate. Thus, the diameter of the opening 25a in the anode mask 25 is set smaller when the second substrate is plated using the plating apparatus 10 than when the first substrate is plated. This makes it possible to increase the film thickness in the central portion of the second substrate. Consequently, the reduction in in-plane uniformity due to the influence of the terminal effect can be curbed on both the first substrate and second substrate.
Furthermore, by adjusting the diameter of the opening 60a in the regulation plate 60 in addition to adjusting the diameter of the opening 25a in the anode mask 25, the plating apparatus 10 of the present embodiment can improve the in-plane uniformity of the plating film on the substrate W.
The regulation plate 60 is placed at a position closer to the substrate W than to the anode mask 25. Consequently, a plating current passing through the opening 60a in the regulation plate 60 becomes less prone to spread to the periphery of the substrate W. Thus, if the diameter of the opening 60a in the regulation plate 60 is decreased, the film thickness on the periphery of the substrate W can be decreased, and if the diameter of the opening 60a in the regulation plate 60 is increased, the film thickness on the periphery of the substrate W can be increased.
Preferably the diameter of the opening 60a in the regulation plate 60 is adjusted as appropriate according to the film thickness distribution on the substrate W, which is changed by adjusting the diameter of the opening 25a in the anode mask 25. Therefore, in plating a second substrate differing from a first substrate in characteristics or processing conditions, the diameter of the opening 25a in the anode mask 25 is adjusted to be smaller or larger than when the first substrate is processed and the diameter of the opening 60a in the regulation plate 60 is changed as appropriate. When the regulation plate 60 has plural first blades 71A and plural second blades 71B such as shown in
Next, a concrete description will be given of changes in profiles of plating films on substrates W, where the profiles are changed by changing the diameter of the opening 25a in the anode mask 25 and the diameter of the opening 60a in the regulation plate 60. Examples in which the regulation plate 60 shown in
As illustrated in
When the substrate W with a low resist aperture ratio is plated with the diameter of the opening 25a set to 270 mm and with the diameter of the opening 60a set to 276 mm (hereinafter this condition will be referred to as condition E), the film thickness in the central portion of the substrate is small and the film thicknesses on the periphery of the substrate is large. This means that the film thickness on the periphery of the substrate has been increased under the influence of the terminal effect. In contrast, when the substrate W with a low resist aperture ratio is plated with the diameter of the opening 25a set to 220 mm and with the diameter of the opening 60a set to 276 mm (hereinafter this condition will be referred to as condition F), since the diameter of the opening 25a is smaller under condition F than under condition E, the film thickness in the central portion of the substrate is larger. Also, when the substrate W with a low resist aperture ratio is plated with the diameter of the opening 25a set to 220 mm and with the diameter of the opening 60a set to 274 mm (hereinafter this condition will be referred to as condition D), since the diameter of the opening 60a is smaller under condition D than under condition F, the film thicknesses on the periphery of the substrate is smaller.
As shown in
As illustrated in
When the substrate W with a thin seed layer is plated with the diameter of the opening 25a set to 270 mm and with the diameter of the opening 60a set to 276 mm (hereinafter this condition will be referred to as condition E), the film thickness in the central portion of the substrate is small and the film thicknesses on the periphery of the substrate is large. This means that the film thickness on the periphery of the substrate has been increased under the influence of the terminal effect. In contrast, when the substrate W with a thin seed layer is plated with the diameter of the opening 25a set to 220 mm and with the diameter of the opening 60a set to 276 mm (hereinafter this condition will be referred to as condition F), since the diameter of the opening 25a is smaller under condition F than under condition E, the film thickness in the central portion of the substrate is larger. Also, when the substrate W with a thin seed layer is plated with the diameter of the opening 25a set to 220 mm and with the diameter of the opening 60a set to 274 mm (hereinafter this condition will be referred to as condition D), since the diameter of the opening 60a is smaller under condition D than under condition F, the film thicknesses on the periphery of the substrate is smaller.
As shown in
As illustrated in
When the substrate W is plated in a plating solution having a comparatively low electrical resistance with the diameter of the opening 25a set to 270 mm and with the diameter of the opening 60a set to 276 mm (hereinafter this condition will be referred to as condition E), the film thickness in the central portion of the substrate is small and the film thicknesses on the periphery of the substrate is large. This means that the film thickness on the periphery of the substrate has been increased under the influence of the terminal effect. In contrast, when the substrate W is plated in a plating solution having a comparatively low electrical resistance with the diameter of the opening 25a set to 220 mm and with the diameter of the opening 60a set to 276 mm (hereinafter this condition will be referred to as condition F), since the diameter of the opening 25a is smaller under condition F than under condition E, the film thickness in the central portion of the substrate is smaller. Also, when the substrate W is plated in a plating solution having a comparatively low electrical resistance with the diameter of the opening 25a set to 220 mm and with the diameter of the opening 60a set to 274 mm (hereinafter this condition will be referred to as condition D), since the diameter of the opening 60a is smaller under condition D than under condition F, the film thicknesses on the periphery of the substrate is smaller.
As shown in
As shown in
Even if the influence of the terminal effect is excluded, the plating film tends to become thick on the periphery of the substrate W because the electric flux spreading outward between the anode mask 25 and substrate W concentrates on the periphery of the substrate W. Adjustment of plating film thickness in a comparatively narrow region on the periphery of the substrate W such as described above is achieved by the opening adjustment portion 63 of the regulation plate 60. The regulation plate 60, which is located close to the substrate W, can directly shield electric fields on the peripheral portion of the substrate W and adjust the plating film thickness even by a comparatively small change in an aperture diameter.
An embodiment of the present invention has been described above, but the embodiment described above is intended to facilitate understanding of the present invention and is not meant to limit the present invention. The present invention can be modified and improved without departing from the spirit and scope of the present invention. Needless to say, the present invention includes equivalents thereof. Also, the components described in the appended claims and in the specification may be used in any combination or any of the components may be omitted as long as at least some of the problems described above can be solved or as long as at least some of the advantageous effects described above can be achieved. For example, in the embodiments described above, the plural aperture blades 27 are used as a mechanism for adjusting the diameter of the opening 25a in the anode mask 25, and the plural first blades 71A and plural second blades 71B are used as a mechanism for adjusting the diameter of the opening 60a in the regulation plate 60. However, the diameter of the opening 25a in the anode mask 25 may be adjusted using the plural first blades 71A and plural second blades 71B and the opening 60a in the regulation plate 60 may be adjusted using the plural aperture blades 27. Also, not only the plural aperture blades 27 and the plural first blades 71A and plural second blades 71B, but also an adjustment mechanism of another form may be adopted.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-248380 | Dec 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/086021 | 12/5/2016 | WO | 00 |
