Fluid delivery system and method for electroplating workpiece

Abstract

A fluid delivery system for an electroplating system is disclosed, comprising: a box suitable for accommodating a fluid; a first fluid conveyor having a first fluid outlet for conveying the fluid into the box, a second fluid conveyor having a second fluid outlet, and a third fluid conveyor having a third fluid outlet, the second fluid conveyor and the third fluid conveyor being used to convey a pressurized fluid into the box in opposite facing directions, the box having an axis along which a workpiece can move relative to the box along the axis between the second fluid outlet and the third fluid outlet, the second fluid conveyor being suitable for conveying the pressurized fluid out of the second fluid outlet to exert a first repulsive force and a second repulsive force on the workpiece offset from the axis toward the second fluid conveyor by a first distance and a second distance, to move the workpiece toward the third fluid conveyor, wherein the first repulsive force is greater than the second repulsive force, and the first distance is greater than the second distance.

Description

Technical Field

[0001] The present invention relates to a fluid delivery system used in a box, in particular to a processing box in an electroplating system, and a method for electroplating a workpiece. Background Art

[0002] In a conventional electroplating machine, a plurality of workpiece carriers can pass through and move relative to a housing containing a treatment solution (e.g., an electroplating solution). Each workpiece carrier can be releasably engaged with a corresponding workpiece to be electroplated. The workpiece carriers can be continuously moved through the housing, i.e., in a straight line one after another, thereby continuously moving the workpieces through the housing. The workpieces to be electroplated are generally rectangular and planar in shape. When the workpieces engage with and are carried by the workpiece carriers, the workpieces are vertically oriented, and the relative main surfaces of the workpieces face sideways. Therefore, an electroplating machine is referred to as a vertical continuous electroplating machine.

[0003] The cathode rod is fixed relative to the housing of the electroplating machine, and each of the workpiece carriers is electrically connected to the cathode rod via a corresponding sliding contact so as to be electrically connected to the cathode rod during movement of the workpiece carrier through and relative to the housing. A plurality of anode plates, each powered by a respective power source, are disposed within the housing and fixed relative to the housing. Thus, when the workpieces are moved by the workpiece carriers through the electroplating solution in the housing, they are affected by the electric field between the cathode rod and the anode plates, causing metal in the electroplating solution to be deposited on the workpieces.

[0004] As is well known, the electroplating tank in a continuous electroplating machine can be as long as 30 to 40 meters, and the effective coverage area of ​​such an electroplating machine can be as short as the width of the workpiece. Since the conductivity of the workpiece depends primarily on the uniformity of the thickness of the plating applied to the workpiece during the electroplating process, it is important to ensure that the major surface of the workpiece is not in physical contact with any other components in the tank. However, in conventional electroplating machines, it is difficult to avoid disturbances as each workpiece moves through the tank, because during electroplating, the fluid jet (e.g., the jet of the electroplating solution) ejected from the nozzle operates in a net momentum conservation manner at any point along the jet axis, and therefore applies less force to the workpiece regardless of the position of the workpiece. Even if the workpiece is held on the centerline by guides or rollers in the tank, these guides or rollers inevitably come into sliding contact with the workpiece at certain points, thereby adversely affecting the quality of electroplating.

[0005] Therefore, the object of the present invention is to provide a fluid delivery system for an electroplating machine and an electroplating method, wherein the above-mentioned disadvantages are alleviated or at least provide a useful alternative for business and the public. In particular, it is found that the above-mentioned disadvantages can be at least alleviated by further improvements and innovations based on existing automatic electroplating systems. Summary of the invention

[0006] According to a first aspect of the present invention, a fluid delivery system for an electroplating system is provided, which at least includes a box body, the box body is suitable for accommodating a fluid, a first fluid conveyor, the first fluid conveyor having a first fluid outlet for conveying the fluid into the box body, a second fluid conveyor having a second fluid outlet and a third fluid conveyor having a third fluid outlet, for conveying pressurized fluid into the box body in opposite directions, the box body having an axis, and a workpiece can move relative to the box body between the second fluid outlet and the third fluid outlet along the axis, wherein the second fluid conveyor is suitable for conveying the pressurized fluid from the second fluid outlet to apply a first repulsive force on the workpiece offset from the axis toward the second fluid conveyor by a first distance, so that the workpiece moves toward the third fluid conveyor, wherein the second fluid conveyor is suitable for conveying the pressurized fluid from the second fluid outlet to apply a second repulsive force on the workpiece offset from the axis toward the second fluid conveyor by a second distance, so that the workpiece moves toward the third fluid conveyor, wherein the first repulsive force is greater than the second repulsive force.

[0007] According to a second aspect of the present invention, a method for electroplating at least one workpiece is provided, comprising the steps of (a) delivering fluid from a first fluid outlet of a first fluid conveyor to a housing, (b) delivering pressurized fluid from a second fluid outlet of a second fluid conveyor and from a third fluid outlet of a third fluid conveyor to the housing in opposite directions, (c) moving the workpiece relative to the housing along an axis between the second fluid outlet and the third fluid outlet, (d) applying a first repulsive force to the workpiece offset from the axis toward the second fluid conveyor by a first distance so as to move the workpiece toward the third fluid conveyor, and (e) applying a second repulsive force to the workpiece offset from the axis toward the second fluid conveyor by a second distance so as to move the workpiece toward the third fluid conveyor, wherein the first repulsive force is greater than the second repulsive force and the first distance is greater than the second distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0009] Figure 1 is a perspective view of a fluid delivery system according to an embodiment of the present invention;

[0010] Figure 2 yes Figure 1 a side view of the fluid delivery system shown;

[0011] Figure 3 yes Figure 1 a partial end view of the fluid delivery system shown;

[0012] Figure 4a yes Figure 1 an end view of the fluid delivery system shown;

[0013] Figure 4b yes Figure 1 another end view of the fluid delivery system shown;

[0014] Figure 5a is a front view of a nozzle of a fluid delivery system according to an embodiment of the present invention;

[0015] Figure 5b is along Figure 5a A cross-sectional view of the nozzle taken along line FF;

[0016] Figure 5c is a schematic side view of the nozzle of FIG5A;

[0017] Figure 5d is a schematic perspective view of the nozzle of FIG. 5A ;

[0018] Figure 5e is a perspective view of the nozzle of FIG. 5A ;

[0019] Figure 6 is a schematic perspective view showing the connection between the nozzle and the pressurizing nozzle;

[0020] Figure 7a is a schematic diagram showing a workpiece significantly offset from a central axis of movement through a process box;

[0021] Figure 7b is a schematic diagram showing a workpiece with a small offset from the central axis;

[0022] Figure 7c is a schematic diagram showing a workpiece aligned within a central axis;

[0023] Figure 8 is a graph of the repulsive force versus the gap distance between the nozzle and the workpiece at two different flow rates;

[0024] Figure 9a is a schematic diagram showing physical contact between a nozzle outlet and a workpiece when there is no flow from the nozzle;

[0025] Figure 9b is a schematic diagram showing a small gap distance between a nozzle outlet and a workpiece when the nozzle delivers a small flow rate;

[0026] Fig.9c is a schematic diagram showing a large gap distance between a nozzle outlet and a workpiece when the nozzle delivers a large flow rate; and

[0027] Fig.10 is a graph showing the repulsive force of three different configurations of nozzle outlets. DETAILED DESCRIPTION

[0028] A schematic diagram of a vertical continuous electroplating machine according to an embodiment of the present invention is shown in FIG. Figures 1 to 4b shown and is usually denoted as 10.

[0029] The electroplating machine 10 includes a tank 12 for containing an electroplating solution. A plurality of workpieces 14 preferably together form a continuous and rollable material that is continuously movable in sequence through and relative to the tank 12. Each workpiece 14 to be plated is releasably engaged so as to physically and electrically connect with a workpiece carrier 15 to establish physical and electrical connection therewith.

[0030] The electroplating machine 10 includes a fluid delivery system 100. The fluid delivery system 100 includes two rows of opposing nozzles 110a, 110b for delivering electroplating solution into the tank 12, the nozzles 110a being fixedly spaced apart from each other. Similarly, the nozzles 110b are also fixedly spaced apart from each other. The workpieces 14 are continuously movable through the tank 12 in a sequence between the nozzles 110a, 110b, such that the first major surface of each workpiece 14 faces the outlet of the nozzle 110a, and the second opposing major surface of each workpiece 14 faces the outlet of the nozzle 110b.

[0031] During operation of the electroplating machine 10, the workpiece 14 may move along the central axis 16 while oscillating substantially perpendicular to the axis. For example, the workpiece 14 may oscillate between a first position where the workpiece 14 is coaxial with the axis 16 and a second position where the workpiece 14 is offset from the axis 16, which is highly undesirable because the workpiece 14 inevitably contacts some physical objects within the tank 12, particularly the nozzles 110a, 110b. This undesirably affects the electroplating performance.

[0032] The fluid delivery system 100 also includes two rows of nozzles, namely a row of second nozzles 120 and a row of third nozzles 130, for compressing the electroplating solution to a higher pressure and delivering the pressurized electroplating solution into the tank 12. The nozzles 120 and 130 are preferably positioned on opposite sides of the workpiece 14 and deliver the pressurized electroplating solution in opposite directions toward each other and toward opposite major surfaces of the workpiece 14.

[0033] The structure of the nozzles 120 and 130 is now described in detail with reference to FIGS. 5A to 5E , each nozzle 120 includes a fluid inlet 121 for receiving the electroplating solution and a fluid outlet 122 for delivering the electroplating solution to the tank 12, the fluid inlet 121 having a circular cross-section, and the fluid outlet 122 having an annular area. The nozzle 120 also includes a flow path 123 for fluidly connecting the fluid inlet 121 and the fluid outlet 122. The cross-sectional area of ​​the flow path 123 converges from the larger cross-sectional area of ​​the fluid inlet 121 to the smaller cross-sectional area of ​​the fluid outlet 122. First, the electroplating solution is introduced into the nozzle 120 through the fluid inlet 121 at a first speed, and is discharged through the fluid outlet 122 at a second speed higher than the first speed after passing through the internal flow path 123.

[0034] The fluid outlet 122 also includes an annular opening 124, i.e., an annular space at the end of the flow path 123. The annular opening 124 can be defined by an outer periphery 125 and an inner periphery 126. The annular opening 124 does not have to be arranged in an annular shape, and the outer periphery 125 and the inner periphery 126 can be arranged in different shapes. For example, the outer periphery 125 and the inner periphery 126 can be individually selected from any trigonometry, such as a circle, a triangle, a polygon, or even any irregular shape.

[0035] The annular opening 124 may extend through a flow path 123 formed between the fluid inlet 121 and the fluid outlet 122. In particular, the annular channel may be formed by a cylindrical stopper member 127 positioned along the flow path 123. The stopper member 127 stabilizes the pressure along the flow path 123 and increases the pressure of the pressurized fluid at the fluid outlet 122. In order to maintain a stable flow, the stopper member 127 is preferably disposed at a central portion of the flow path 123. That is, if the nozzle body 120 and the stopper member 127 are both cylindrical, the nozzle body 120 and the stopper member 127 are concentrically arranged.

[0036] refer to Figure 6 In an exemplary embodiment shown in FIG. 1 , the first nozzle 110a and the second nozzle 120 are connected to the common fluid pipe 140 upstream, while the first nozzle 110b ( Figure 6 The second nozzle 120 and the third nozzle 130 are connected to another common fluid pipe 150. The diameters of the second nozzle 120 and the third nozzle 130 are larger than the diameters of the first nozzles 110a and 110b. The second nozzle 120 and the third nozzle 130 are closer to the workpiece 14 than the first nozzles 110a and 110b. Therefore, the flow rate at the fluid outlet 122 of the second nozzle 120 and the flow rate at the fluid outlet of the third nozzle 130 will be greater than the flow rate at the outlet of the nozzles 110a and 110b.

[0037] For example, fluid streams are introduced through inlets 142 and 152 of fluid pipes 140 and 150, respectively. Fluid streams with lower speeds are discharged through outlets of first nozzles 110A and 110b, respectively. Fluid streams with higher speeds are discharged through outlets of second and third nozzles 120 and 130. Preferably, the second nozzle 120 and the third nozzle 130 are each located between the two first nozzles 110a and 110b spaced apart from each other by a minimum distance.

[0038] Reference Figures 7a to 7c , the fluid enters the fluid inlet 121 at a relatively low velocity with a high static pressure. Subsequently, the fluid is accelerated to a higher velocity by the pressure drop (due to Bernoulli's theorem) and leaves the fluid outlet 122 through the annular opening area 128 (i.e., 2πrt) formed between the circular flange of the fluid outlet 122 and the workpiece 14. In theory, the final static pressure of the fluid leaving the fluid outlet 122 must be equal to the pressure of the external fluid in the housing 12, so the pressure of the fluid upstream of the annular opening 124 is higher than the pressure of the external fluid, and this pressure difference creates a "cushion" between them. Therefore, the cushion layer exerts a repulsive force on the workpiece 14, which depends on the pressure difference between the fluid escaping at the fluid outlet 122 and the external fluid pressure.

[0039] The inventors have also devised through their own research that the repulsive force applied to the workpiece 14 is inversely related to the corresponding gap thickness t between the fluid outlet 122, 132 and the workpiece 14. The disturbance of the workpiece 14 from the axis 16 to one of the nozzles 120, 130 will reduce the annular area 128 and in turn increase the fluid velocity through the annular opening. Based on Bernoulli's theorem, the upstream pressure will increase with the square of the provided velocity and also increase inversely with the square of the annular area 128. Therefore, the closer the workpiece 14 is positioned relative to the fluid outlet 122, the greater the reduction in the area of ​​the annular opening 128, and the greater the repulsive force applied to the workpiece 14.

[0040] In use, the workpiece 14 can move along the axis 16 and deflect from the axis 16 due to the flow from the first nozzles 110a, 110b. The workpiece 14 can move along the axis 16 between the second fluid nozzle 120 and the third fluid nozzle 130 and deflect from the axis 16 due to the flow of fluid delivered by the first nozzles 110a, 110b. Figure 7a , the workpiece 14 having a larger offset d1 from the axis 16, i.e., a smaller gap t, is subjected to a repulsive force F1 by the pressurized fluid delivered from the second fluid outlet 122 and movable toward the third fluid outlet 132. Alternatively, as Figure 7bAs shown, the workpiece 14 having a small offset d2 from the axis 16, i.e., a large gap t, is exerted with a nominal repulsive force F2 by the pressurized fluid delivered from the second fluid outlet 122 and movable toward the third fluid outlet 132. If the workpiece 14 is positioned substantially aligned with the axis 16, i.e., without offset, as shown in FIG. 7C , the pressurized fluid delivered from the second fluid outlet 122 will not exert any additional force on the workpiece 14 or at most a negligible force.

[0041] In addition, the inventors have also designed that the repulsive force applied to the workpiece 14 is related to the flow rate of the nozzles 120 and 130. Figure 8 , which shows the repulsive force applied to the workpiece 14 at different gap thicknesses between the nozzles 120 , 130 and the workpiece 14 . Generally, the greater the flow rate of the pressurized flow sprayed to the workpiece 14 , the greater the repulsive force applied to the main surface of the workpiece 14 .

[0042] Now refer to Figure 9a , 9b 9c, which are used for three different configurations, wherein the second and third nozzles 120, 130 operate at different flow rates. If the nozzle 120 provides zero flow, the distance between the nozzle outlet and the workpiece 14 is negligible, and can even be as low as zero distance (see FIG. 1 ) due to the spray momentum of the first nozzle 110b in the opposite direction. Figure 9a If the nozzle 120 provides a smaller flow rate, the effective distance between the nozzle outlet and the workpiece 14 is smaller, for example, 2 mm (see Figure 9b Finally, if the nozzle 120 provides a larger flow rate, the effective distance between the nozzle outlet and the workpiece 14 is larger, for example 4 mm (see Fig.9c ).

[0043] The second and third nozzles 120, 130 should be spaced apart from each other at a desired gap distance. If the second and third nozzles 120, 130 are spaced apart from each other by a small distance, the repulsive force exerted on the workpiece 14 by one nozzle, such as 120, will be too great and push the workpiece 14 past the axis 16 and toward the other nozzle 130. If the second and third nozzles 120, 130 are spaced apart from each other by too large a distance, the repulsive force exerted on the workpiece 14 by one nozzle 120 will be negligible and insufficient to push the workpiece 14 toward the axis 16 and compensate for the deviation. Most preferably, the second and third nozzles 120, 130 should be disposed between gap distances slightly wider than the thickness of the workpiece 14 so that deviation of the workpiece 14 from the axis 16 will be compensated by the pressurized flows of the fluid outlets 122, 132 from two opposite directions.

[0044] Fig.10, where the performance of two outlets 122A, 122B with stop members 127 is compared to the performance of outlet 122C without stop members 127 (control experiment). In general, if the stop member 127 is removed from the fluid outlet 122, the performance of the outlet 122 is significantly reduced.

[0045] It should be understood that the above merely illustrates examples in which the present invention may be implemented, and that various modifications and / or changes may be made thereto without departing from the concept of the present invention.

[0046] It should also be understood that certain features of the present invention described in the context of separate embodiments for clarity may be provided in combination in a single embodiment. Conversely, for brevity, various features of the present invention described in the context of a single embodiment may also be provided individually or in any suitable sub-combination.

Claims

1. A fluid delivery system for an electroplating system, comprising: at least one tank adapted to contain a fluid, a first fluid conveyor, a second fluid conveyor and a third fluid conveyor, the first fluid conveyor having a first fluid outlet for conveying the fluid into the housing, the second fluid conveyor having a second fluid outlet, the third fluid conveyor having a third fluid outlet, the second fluid conveyor and the third fluid conveyor being used to convey pressurized fluid into the housing in opposite facing directions, the housing having an axis, the workpiece being movable relative to the housing along the axis between the second fluid outlet and the third fluid outlet, Wherein, the first fluid conveyors are arranged in two rows opposite to each other, wherein, when the workpiece moves between the second fluid outlet and the third fluid outlet along the axis relative to the box, the first main surface of the workpiece faces the second fluid outlet, and the second main surface of the workpiece opposite to the first main surface faces the third fluid outlet, and the second fluid outlet and the third fluid outlet are both closer to the workpiece than the first fluid outlet, wherein the workpiece can be moved continuously in sequence through the housing between the two rows of opposite first fluid conveyors such that the first major surface of the workpiece faces the first fluid outlet and the second major surface of the workpiece faces the opposite first fluid outlet, wherein the second fluid conveyor is adapted to convey the pressurized fluid from the second fluid outlet to exert a first repulsive force on the workpiece offset a first distance from the axis toward the second fluid conveyor, so as to move the workpiece toward the third fluid conveyor, wherein the second fluid conveyor is adapted to convey the pressurized fluid from the second fluid outlet to exert a second repulsive force on the workpiece offset a second distance from the axis toward the second fluid conveyor, so as to move the workpiece toward the third fluid conveyor, The first repulsive force is greater than the second repulsive force, and the first distance is greater than the second distance.

2. The fluid delivery system according to claim 1, wherein: The pressure of the pressurized fluid at the second fluid outlet and / or the third fluid outlet is inversely related to the distance between the second fluid outlet and / or the third fluid outlet and the workpiece.

3. The fluid delivery system according to claim 1, wherein: Pressurized fluid is delivered to the workpiece at a first velocity offset from the axis by the first distance, and pressurized fluid is delivered to the workpiece at a second velocity offset from the axis by the second distance, wherein the first velocity is higher than the second velocity.

4. The fluid delivery system according to claim 1, wherein: The second fluid conveyor and the third fluid conveyor each further include a fluid inlet through which the fluid is introduced at a relatively low velocity and is conveyed to the tank at a relatively high velocity through the second fluid outlet and / or the third fluid outlet, respectively.

5. The fluid delivery system according to claim 1, wherein: The distance between the second fluid outlet and the workpiece is inversely related to the repulsive force exerted on the workpiece by the fluid exiting from the second fluid outlet.

6. The fluid delivery system according to claim 4, wherein: The second fluid conveyor and / or the third fluid conveyor each further includes a stopper member extending along a flow path formed between the fluid inlet and the fluid outlet and located at a central portion of the flow path.

7. The fluid delivery system according to claim 6, wherein: The stop member is adapted to stabilize pressure along the flow path and increase the pressure of the pressurized fluid at the fluid outlet.

8. The fluid delivery system according to claim 1, wherein: The second fluid outlet and / or the third fluid outlet each comprise an annular opening.

9. The fluid delivery system according to claim 8, wherein: The annular opening is formed by an outer periphery and an inner periphery.

10. The fluid delivery system according to claim 9, wherein: The outer periphery and the inner periphery have different shapes.

11. The fluid delivery system of claim 1, further comprising a plurality of groups of the second fluid delivery devices and the third fluid delivery devices, each group being fixedly spaced apart from one another.

12. The fluid delivery system according to claim 1, wherein: The workpiece is spaced apart from the second fluid outlet and / or the third fluid outlet by a minimum distance.

13. The fluid delivery system according to claim 1, wherein: The diameters of the second fluid conveyor and the third fluid conveyor are larger than the diameter of the first fluid conveyor.

14. The fluid delivery system according to claim 1, wherein: The pressure of the pressurized fluid at the second fluid outlet and / or the third fluid outlet is greater than the external pressure of the fluid contained in the tank.

15. The fluid delivery system of claim 1, wherein: The fluid is an electroplating solution.

16. A method of electroplating at least one workpiece, comprising the steps of: (a) delivering the fluid from the first fluid outlets of the two oppositely arranged rows of first fluid delivery devices into the box; (b) delivering pressurized fluid from the second fluid outlet of the second fluid delivery device and from the third fluid outlet of the third fluid delivery device into the housing in oppositely facing directions, (c) moving the workpiece relative to the housing along an axis between the second fluid outlet and the third fluid outlet so that a first main surface of the workpiece faces the second fluid outlet, a second main surface of the workpiece opposite to the first main surface faces the third fluid outlet, and the second fluid outlet and the third fluid outlet are both closer to the workpiece than the first fluid outlet, (d) moving the workpiece in sequence through the housing between the two opposing rows of first fluid conveyors with the first major surface of the workpiece facing the first fluid outlet and the second major surface of the workpiece facing the opposing first fluid outlet, (e) applying a first repulsive force to the workpiece offset a first distance from the axis toward the second fluid transporter to move the workpiece toward the third fluid transporter, and (f) applying a second repulsive force to the workpiece offset a second distance from the axis toward the second fluid conveyor to move the workpiece toward the third fluid conveyor, The first repulsive force is greater than the second repulsive force, and the first distance is greater than the second distance.

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